1
|
Svenning JC, Buitenwerf R, Le Roux E. Trophic rewilding as a restoration approach under emerging novel biosphere conditions. Curr Biol 2024; 34:R435-R451. [PMID: 38714176 DOI: 10.1016/j.cub.2024.02.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2024]
Abstract
Rewilding is a restoration approach that aims to promote self-regulating complex ecosystems by restoring non-human ecological processes while reducing human control and pressures. Rewilding is forward-looking in that it aims to enhance functionality for biodiversity, accepting and indeed promoting the dynamic nature of ecosystems, rather than fixating on static composition or structure. Rewilding is thus especially relevant in our epoch of increasingly novel biosphere conditions, driven by strong human-induced global change. Here, we explore this hypothesis in the context of trophic rewilding - the restoration of trophic complexity mediated by wild, large-bodied animals, known as 'megafauna'. This focus reflects the strong ecological impacts of large-bodied animals, their widespread loss during the last 50,000 years and their high diversity and ubiquity in the preceding 50 million years. Restoring abundant, diverse, wild-living megafauna is expected to promote vegetation heterogeneity, seed dispersal, nutrient cycling and biotic microhabitats. These are fundamental drivers of biodiversity and ecosystem function and are likely to gain importance for maintaining a biodiverse biosphere under increasingly novel ecological conditions. Non-native megafauna species may contribute to these effects as ecological surrogates of extinct species or by promoting ecological functionality within novel assemblages. Trophic rewilding has strong upscaling potential via population growth and expansion of wild fauna. It is likely to facilitate biotic adaptation to changing climatic conditions and resilience to ecosystem collapse, and to curb some negative impacts of globalization, notably the dominance of invasive alien plants. Finally, we discuss the complexities of realizing the biodiversity benefits that trophic rewilding offers under novel biosphere conditions in a heavily populated world.
Collapse
Affiliation(s)
- Jens-Christian Svenning
- Center for Ecological Dynamics in a Novel Biosphere (ECONOVO), Department of Biology, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark.
| | - Robert Buitenwerf
- Center for Ecological Dynamics in a Novel Biosphere (ECONOVO), Department of Biology, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark
| | - Elizabeth Le Roux
- Center for Ecological Dynamics in a Novel Biosphere (ECONOVO), Department of Biology, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark; Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, Mammal Research Institute, University of Pretoria, Pretoria 0028, South Africa
| |
Collapse
|
2
|
Britnell JA, Kerley GIH, Antwis R, Shultz S. A grazer's niche edge is associated with increasing diet diversity and poor population performance. Ecol Lett 2024; 27:e14357. [PMID: 38193626 DOI: 10.1111/ele.14357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/09/2023] [Accepted: 12/05/2023] [Indexed: 01/10/2024]
Abstract
The core-periphery hypothesis predicts niche cores should be associated with greater survivorship, reproductive output and population performance rates than marginal habitats at niche edges. However, there is very little empirical evidence of whether niche centrality influences population trends in animals. Using the Cape mountain zebra (Equus zebra zebra) as a model system, we evaluated whether niche centrality is associated with population trends, resource availability and diet across a core-periphery gradient. Population growth rates and density progressively declined towards niche peripheries. Niche peripheries were resource-poor and Cape mountain zebra consumed more phylogenetically diverse diets dominated by non-grass families. In core habitats they consumed grass-rich diets and female reproductive success was higher. This combination of spatial niche modelling and functional ecology provides a novel evaluation of how bottom-up resource limitation can shape species distributions, population resilience and range change and can guide conservation management.
Collapse
Affiliation(s)
- J A Britnell
- School of Earth and Environmental Sciences, University of Manchester, Manchester, UK
- North of England Zoological Society (Chester Zoo), Upton-by-Chester, UK
| | - G I H Kerley
- Centre for African Conservation Ecology, Nelson Mandela University, Gqeberha, South Africa
| | | | - S Shultz
- School of Earth and Environmental Sciences, University of Manchester, Manchester, UK
| |
Collapse
|
3
|
Tóth Z, Bartók R, Nagy Z, Szappanos VR. The relative importance of social information use for population abundance in group-living and non-grouping prey. J Theor Biol 2023; 575:111626. [PMID: 37758120 DOI: 10.1016/j.jtbi.2023.111626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/07/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023]
Abstract
Predator-prey relationships are fundamental components of ecosystem functioning, within which the spatial consequences of prey social organization can alter predation rates. Group-living (GL) species are known to exploit inadvertent social information (ISI) that facilitates population persistence under predation risk. Still, the extent to which non-grouping (NG) prey can benefit from similar processes is unknown. Here we built an individual-based model to explore and compare the population-level consequences of ISI use in GL and NG prey. We differentiated between GL and NG prey only by the presence or absence of social attraction toward conspecifics that drives individual movement patterns. We found that the extent of the benefits of socially acquired predator information in NG highly depends on the prey's ability to detect nearby predators, prey density and the occurrence of false alarms. Conversely, even moderate probabilities of ISI use and predator detection can lead to maximal population-level benefits in GL prey. This theoretical work provides additional insights into the conditions under which ISI use can facilitate population persistence irrespective of prey social organisation.
Collapse
Affiliation(s)
- Zoltán Tóth
- Department of Zoology, Plant Protection Institute, Centre for Agricultural Research, HUN-REN, Budapest, Hungary; University of Debrecen, Debrecen, Hungary.
| | | | | | | |
Collapse
|
4
|
Martin EC, Hansen BB, Herfindal I, Lee AM. The role of seasonal migration in spatial population synchrony. Ecology 2023; 104:e4158. [PMID: 37632351 DOI: 10.1002/ecy.4158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/03/2023] [Accepted: 07/29/2023] [Indexed: 08/28/2023]
Abstract
Spatially synchronized population dynamics are common in nature, and understanding their causes is key for predicting species persistence. A main driver of synchrony between populations of the same species is shared environmental conditions, which cause populations closer together in space to be more synchronized than populations further from one another. Most theoretical and empirical understanding of this driver considers resident species. For migratory species, however, the degree of spatial autocorrelation in the environment may change across seasons and vary by their geographic location along the migratory route or on a nonbreeding ground, complicating the synchronizing effect of the environment. Migratory species show a variety of different strategies in how they disperse to and aggregate on nonbreeding grounds, ranging from completely shared nonbreeding grounds to multiple different ones. Depending on the sensitivity to environmental conditions off the breeding grounds, we can expect that migration and overwintering strategies will impact the extent and spatial pattern of population synchrony on the breeding grounds. Here, we use spatial population-dynamic modeling and simulations to investigate the relationship between seasonal environmental autocorrelation and migration characteristics. Our model shows that the effects of environmental autocorrelation experienced off the breeding ground on population synchrony depend on the number and size of nonbreeding grounds, and how populations migrate in relation to neighboring populations. When populations migrated to multiple nonbreeding grounds, spatial population synchrony increased with increasing environmental autocorrelation between nonbreeding grounds. Populations that migrated to the same place as near neighbors had higher synchrony at short distances than populations that migrated randomly. However, synchrony declined less across increasing distances for the random migration strategy. The differences in synchrony between migration strategies were most pronounced when the environmental autocorrelation between nonbreeding grounds was low. These results show the importance of considering migration when studying spatial population synchrony and predicting patterns of synchrony and population viability under global environmental change. Climate change and habitat loss and fragmentation may cause range shifts and changes in migratory strategies, as well as changes in the mean and spatial autocorrelation of the environment, which can alter the scale and patterns observed in spatial population synchrony.
Collapse
Affiliation(s)
- Ellen C Martin
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, Trondheim, Norway
| | - Brage Bremset Hansen
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Terrestrial Ecology, Norwegian Institute for Nature Research, Trondheim, Norway
| | - Ivar Herfindal
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, Trondheim, Norway
- The Gjaerevoll Centre for Biodiversity Foresight Analyses, Norwegian University of Science and Technology, Trondheim, Norway
| | - Aline Magdalena Lee
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, Trondheim, Norway
- The Gjaerevoll Centre for Biodiversity Foresight Analyses, Norwegian University of Science and Technology, Trondheim, Norway
| |
Collapse
|
5
|
Rossiter P. Setting the record straight on rinderpest vaccination. Vet Rec 2023; 193:332. [PMID: 37861169 DOI: 10.1002/vetr.3591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
|
6
|
David-Barrett T. Human group size puzzle: why it is odd that we live in large societies. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230559. [PMID: 37593705 PMCID: PMC10427830 DOI: 10.1098/rsos.230559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 07/21/2023] [Indexed: 08/19/2023]
Abstract
Human groups tend to be much larger than those of non-human primates. This is a puzzle. When ecological factors do not limit primate group size, the problem of coordination creates an upper threshold even when cooperation is guaranteed. This paper offers a model of group coordination towards behavioural synchrony to spell out the mechanics of group size limits, and thus shows why it is odd that humans live in large societies. The findings suggest that many of our species' evolved social behaviours and culturally maintained social technologies emerged as solutions to this problem.
Collapse
|
7
|
Kiffney PM, Lisi PJ, Liermann M, Naman SM, Anderson JH, Bond MH, Pess GR, Koehler ME, Buhle ER, Buehrens TW, Klett RS, Cram JM, Quinn TP. Colonization of a temperate river by mobile fish following habitat reconnection. Ecosphere 2023. [DOI: 10.1002/ecs2.4336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Affiliation(s)
- P. M. Kiffney
- Fish Ecology, Northwest Fisheries Science Center National Marine Fisheries Service, NOAA Seattle Washington USA
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA
| | - P. J. Lisi
- Washington Department of Fish and Wildlife Olympia Washington USA
| | - M. Liermann
- Fish Ecology, Northwest Fisheries Science Center National Marine Fisheries Service, NOAA Seattle Washington USA
| | - S. M. Naman
- Department of Zoology University of British Columbia Vancouver British Columbia Canada
- Fisheries and Oceans Canada Freshwaer Ecosystems Section Cultus Lake British Columbia Canada
| | - J. H. Anderson
- Washington Department of Fish and Wildlife Olympia Washington USA
| | - M. H. Bond
- Fish Ecology, Northwest Fisheries Science Center National Marine Fisheries Service, NOAA Seattle Washington USA
| | - G. R. Pess
- Fish Ecology, Northwest Fisheries Science Center National Marine Fisheries Service, NOAA Seattle Washington USA
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA
| | | | - E. R. Buhle
- Affiliate, Northwest Fisheries Science Center National Marine Fisheries Service, NOAA Seattle Washington USA
- Mount Hood Environmental Sandy Oregon USA
| | - T. W. Buehrens
- Washington Department of Fish and Wildlife Ridgefield Washington USA
| | - R. S. Klett
- Colville Indian Tribes Nespelem Washington USA
| | - J. M. Cram
- Washington Department of Fish and Wildlife Wenatchee Washington USA
| | - T. P. Quinn
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA
| |
Collapse
|
8
|
Burton-Roberts R, Cordes LS, Slotow R, Vanak AT, Thaker M, Govender N, Shannon G. Seasonal range fidelity of a megaherbivore in response to environmental change. Sci Rep 2022; 12:22008. [PMID: 36550171 PMCID: PMC9780231 DOI: 10.1038/s41598-022-25334-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
For large herbivores living in highly dynamic environments, maintaining range fidelity has the potential to facilitate the exploitation of predictable resources while minimising energy expenditure. We evaluate this expectation by examining how the seasonal range fidelity of African elephants (Loxodonta africana) in the Kruger National Park, South Africa is affected by spatiotemporal variation in environmental conditions (vegetation quality, temperature, rainfall, and fire). Eight-years of GPS collar data were used to analyse the similarity in seasonal utilisation distributions for thirteen family groups. Elephants exhibited remarkable consistency in their seasonal range fidelity across the study with rainfall emerging as a key driver of space-use. Within years, high range fidelity from summer to autumn and from autumn to winter was driven by increased rainfall and the retention of high-quality vegetation. Across years, sequential autumn seasons demonstrated the lowest levels of range fidelity due to inter-annual variability in the wet to dry season transition, resulting in unpredictable resource availability. Understanding seasonal space use is important for determining the effects of future variability in environmental conditions on elephant populations, particularly when it comes to management interventions. Indeed, over the coming decades climate change is predicted to drive greater variability in rainfall and elevated temperatures in African savanna ecosystems. The impacts of climate change also present particular challenges for elephants living in fragmented or human-transformed habitats where the opportunity for seasonal range shifts are greatly constrained.
Collapse
Affiliation(s)
- Rhea Burton-Roberts
- grid.7362.00000000118820937School of Natural Sciences, Bangor University, Bangor, Gwynedd UK
| | - Line S. Cordes
- grid.7362.00000000118820937School of Ocean Sciences, Bangor University, Bangor, Gwynedd UK
| | - Rob Slotow
- grid.16463.360000 0001 0723 4123School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Abi Tamim Vanak
- grid.16463.360000 0001 0723 4123School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa ,grid.464760.70000 0000 8547 8046Centre for Biodiversity and Conservation, Ashoka Trust for Research in Ecology and the Environment, Bangalore, India
| | - Maria Thaker
- grid.34980.360000 0001 0482 5067Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India
| | - Navashni Govender
- grid.463628.d0000 0000 9533 5073Conservation Management, Kruger National Park, South African National Parks, Private Bag X402, Skukuza, 1350 South Africa ,grid.412139.c0000 0001 2191 3608School of Natural Resource Management, Nelson Mandela University, Private Bag X6531, George, 6530 South Africa
| | - Graeme Shannon
- grid.7362.00000000118820937School of Natural Sciences, Bangor University, Bangor, Gwynedd UK
| |
Collapse
|
9
|
Watson F, Becker MS, Smit D, Droge E, Mukula T, Martens S, Mwaba S, Christianson D, Creel S, Brennan A, M'soka J, Gaylard A, Simukonda C, Nyirenda M, Mayani B. Predation strongly limits demography of a keystone migratory herbivore in a recovering transfrontier ecosystem. Ecol Evol 2022; 12:e9414. [PMID: 36262265 PMCID: PMC9575999 DOI: 10.1002/ece3.9414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 08/19/2022] [Accepted: 08/23/2022] [Indexed: 11/20/2022] Open
Abstract
Large herbivore migrations are imperiled globally; however the factors limiting a population across its migratory range are typically poorly understood. Zambia's Greater Liuwa Ecosystem (GLE) contains one of the largest remaining blue wildebeest (Connochaetes taurinus taurinus) migrations, yet the population structure, vital rates, and limiting factors are virtually unknown. We conducted a long‐term demographic study of GLE wildebeest from 2012 to 2019 of 107 collared adult females and their calves, 7352 herd observations, 12 aerial population surveys, and concurrent carnivore studies. We applied methods of vital rate estimation and survival analysis within a Bayesian estimation framework. From herd composition observations, we estimated rates of fecundity, first‐year survival, and recruitment as 68%, 56%, and 38% respectively, with pronounced interannual variation. Similar rates were estimated from calf‐detections with collared cows. Adult survival rates declined steadily from 91% at age 2 years to 61% at age 10 years thereafter dropping more sharply to 2% at age 16 years. Predation, particularly by spotted hyena, was the predominant cause of death for all wildebeest ages and focused on older animals. Starvation only accounted for 0.8% of all unbiased known natural causes of death. Mortality risk differed substantially between wet and dry season ranges, reflecting strong spatio‐temporal differences in habitat and predator densities. There was substantial evidence that mortality risk to adults was 27% higher in the wet season, and strong evidence that it was 45% higher in the migratory range where predator density was highest. The estimated vital rates were internally consistent, predicting a stable population trajectory consistent with aerial estimates. From essentially zero knowledge of GLE wildebeest dynamics, this work provides vital rates, age structure, limiting factors, and a plausible mechanism for the migratory tendency, and a robust model‐based foundation to evaluate the effects of potential restrictions in migratory range, climate change, predator–prey dynamics, and poaching.
Collapse
Affiliation(s)
- Fred Watson
- California State University Monterey BaySeasideCaliforniaUSA,Zambian Carnivore ProgrammeMfuweZambia
| | - Matthew S. Becker
- Zambian Carnivore ProgrammeMfuweZambia,Conservation Biology and Ecology Program, Department of EcologyMontana State UniversityBozemanMontanaUSA
| | - Daan Smit
- Zambian Carnivore ProgrammeMfuweZambia
| | - Egil Droge
- Zambian Carnivore ProgrammeMfuweZambia,Wildlife Conservation Research Unit, The Recanati‐Kaplan Centre, Department of ZoologyUniversity of OxfordOxfordUK
| | - Teddy Mukula
- Zambian Carnivore ProgrammeMfuweZambia,African Parks Zambia, Liuwa Plain National ParkKalaboZambia,Worldwide Fund for NatureLusakaZambia
| | | | - Shadrach Mwaba
- Zambian Carnivore ProgrammeMfuweZambia,Worldwide Fund for NatureLusakaZambia
| | - David Christianson
- Zambian Carnivore ProgrammeMfuweZambia,Department of Ecosystem Science and ManagementUniversity of WyomingLaramieWyomingUSA
| | - Scott Creel
- Zambian Carnivore ProgrammeMfuweZambia,Conservation Biology and Ecology Program, Department of EcologyMontana State UniversityBozemanMontanaUSA,Institutionen för Vilt, Fisk och Miljö, Sveriges LantbruksuniversitetUmeåSweden
| | | | - Jassiel M'soka
- Zambian Carnivore ProgrammeMfuweZambia,U.S. Agency for International DevelopmentLusakaZambia
| | - Angela Gaylard
- African Parks Zambia, Liuwa Plain National ParkKalaboZambia
| | - Chuma Simukonda
- Zambia Department of National Parks and WildlifeChilangaZambia
| | | | | |
Collapse
|
10
|
Torney CJ, Laxton M, Lloyd‐Jones DJ, Kohi EM, Frederick HL, Moyer DC, Mrisha C, Mwita M, Hopcraft JGC. Estimating the abundance of a group‐living species using multi‐latent spatial models. Methods Ecol Evol 2022. [DOI: 10.1111/2041-210x.13941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Colin J. Torney
- School of Mathematics and Statistics University of Glasgow Glasgow UK
| | - Megan Laxton
- School of Mathematics and Statistics University of Glasgow Glasgow UK
| | - David J. Lloyd‐Jones
- FitzPatrick Institute of African Ornithology DST‐NRF Centre of Excellence University of Cape Town Cape Town South Africa
| | - Edward M. Kohi
- Conservation Information Monitoring Unit Tanzania Wildlife Research Institute Arusha Tanzania
| | | | - David C. Moyer
- Integrated Research Center The Field Museum of Natural History Chicago IL USA
| | - Chediel Mrisha
- Ministry of the Natural Resources and Tourism Dodoma Tanzania
| | - Machoke Mwita
- Conservation Information Monitoring Unit Tanzania Wildlife Research Institute Arusha Tanzania
| | - J. Grant C. Hopcraft
- Institute of Biodiversity Animal Health & Comparative Medicine University of Glasgow Glasgow UK
| |
Collapse
|
11
|
Gortázar C, Fernandez-de-Simon J. One tool in the box: the role of hunters in mitigating the damages associated to abundant wildlife. EUR J WILDLIFE RES 2022. [DOI: 10.1007/s10344-022-01578-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
12
|
Mwampeta SB, Wilton CM, Mkasanga IJ, Bled F, Masinde LM, Røskaft E, Ranke PS, Fyumagwa R, Belant JL. Efficacy of spotlights and thermal cameras to detect lions
Panthera leo
and spotted hyenas
Crocuta crocuta
depends on species and management regime. WILDLIFE BIOLOGY 2022. [DOI: 10.1002/wlb3.01030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Stanslaus B. Mwampeta
- Dept of Biology, Norwegian Univ. of Science and Technology (NTNU) Realfagbygget Trondheim Norway
- Global Wildlife Conservation Center, State Univ. of New York College of Environmental Science and Forestry Syracuse NY USA
| | | | - Imani J. Mkasanga
- Global Wildlife Conservation Center, State Univ. of New York College of Environmental Science and Forestry Syracuse NY USA
| | - Florent Bled
- Carnivore Ecology Laboratory, Forest and Wildlife Research Center, Mississippi State Univ. MS USA
| | | | - Eivin Røskaft
- Dept of Biology, Norwegian Univ. of Science and Technology (NTNU) Realfagbygget Trondheim Norway
| | - Peter S. Ranke
- Centre for Biodiversity Dynamics, Dept. of Biology, Norwegian Univ. of Science and Technology (NTNU) Realfagbygget Trondheim Norway
| | | | - Jerrold L. Belant
- Global Wildlife Conservation Center, State Univ. of New York College of Environmental Science and Forestry Syracuse NY USA
| |
Collapse
|
13
|
Ectoparasite load of small mammals in the Serengeti Ecosystem: effects of land use, season, host species, age, sex and breeding status. Parasitol Res 2022; 121:823-838. [PMID: 35122139 PMCID: PMC8858283 DOI: 10.1007/s00436-022-07439-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 01/11/2022] [Indexed: 11/03/2022]
Abstract
Ectoparasite load in small mammals can be influenced by both environmental conditions and host species characteristics. However, the nature of these influences is poorly understood in many ecosystems. We used zero-inflated negative binomial (ZINB) regression models with a log link function to assess variation in ectoparasite load among 19 small mammal host species across different land uses (protection in a park, pastoralism and agriculture), habitat types, seasons, age classes, sexes and breeding statuses. We collected 4258 ectoparasites from 612 individual belonging to 19 different species of small mammals. The average ectoparasite load per individual was higher in the pastoral and agricultural lands than in the National Park. Ectoparasite load varied among species and was the highest for the four common and generalist small mammal species (Aethomys sp., Arvicanthis niloticus, Mastomys natalensis, and Gerbilliscus vicinus), most notably in the disturbed pastoral and agricultural lands. It was also higher in the dry than the wet season and for adult males than adult females. These patterns partly reflect the greater mobility of small mammals in the drier conditions; in addition the large body size and home range of males increase the likelihood of encountering parasites. Human disturbance was associated with elevated ectoparasitic load among the small mammals and hence elevated risk of transmission of ectoparasites to humans. As a result, understanding the effect of habitat disturbance on ectoparasite load and its link to zoonotic disease risk should be an important conservation goal and public health priority. Moreover, effective pest control strategies should consider variation in ectoparasite load with land use, habitat type, season and species characteristics.
Collapse
|
14
|
Lee PC, Moss CJ, Njiraini N, Poole JH, Sayialel K, Fishlock VL. Cohort consequences of drought and family disruption for male and female African elephants. Behav Ecol 2021. [DOI: 10.1093/beheco/arab148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Cohort effects, reflecting early adversity or advantage, have persisting consequences for growth, reproductive onset, longevity, and lifetime reproductive success. In species with prolonged life histories, cohort effects may establish variation in age-sex structures, while social structure may buffer individuals against early adversity. Using periods of significant ecological adversity, we examined cohort effects for male and female elephants (Loxodonta africana) over almost 50 years in Amboseli, Kenya. Mortality spiked during severe droughts with highest mortality among calves under 2 years and females over 40 years. Deaths of oldest females resulted in social disruption via matriarch turnover, with potential impacts on resource acquisition for survivors. We predicted that survivors of high mortality and social challenges would have altered life-history trajectories, with later age at first reproduction and reduced age-specific fertility for females and slow transitions to independence and late-onset of potential mating or musth among males. Contrary to expectations, there were no persisting early drought effects on female age at first conception while matriarch loss around puberty accelerated reproductive onset. Experience of an early life drought did not influence age-specific reproductive rates once females commenced reproduction. Males who survived an early drought exhibited complex consequences: male age at family independence was later with larger peer cohort size, but earlier with drought in year of independence (13.9 vs 14.6 years). Early drought had no effect on age at first musth, but male reproductive onset was weakly associated with the number of peers (negative) and age at independence (positive).
Collapse
Affiliation(s)
- Phyllis C Lee
- Amboseli Trust for Elephants, Langata, Nairobi, Kenya
- Behaviour & Evolution Research Group, Psychology, Faculty of Natural Sciences, University of Stirling, Stirling, UK
| | | | | | - Joyce H Poole
- ElephantVoices, Buskhellinga 3, 3236 Sandefjord, Norway
| | | | - Vicki L Fishlock
- Amboseli Trust for Elephants, Langata, Nairobi, Kenya
- Centre for Ecology and Conservation, College of Life & Environmental Sciences, University of Exeter, UK
| |
Collapse
|
15
|
Marshal JP, Tshabalala T, Parrini F. Selection of Vegetation Greenness by Nyala Antelopes on a Resource Productivity Gradient. AFRICAN JOURNAL OF WILDLIFE RESEARCH 2021. [DOI: 10.3957/056.051.0193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Jason P. Marshal
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, 2050 South Africa
| | - Thulani Tshabalala
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, 2050 South Africa
| | - Francesca Parrini
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, 2050 South Africa
| |
Collapse
|
16
|
Finch N, Pople A, McLeod SR, Wallace G. Advances in aerial survey methods for macropods in New South Wales and Queensland. ECOLOGICAL MANAGEMENT & RESTORATION 2021. [DOI: 10.1111/emr.12486] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
17
|
Nhleko ZN, Ahrens R, Ferreira SM, McCleery RA. Poaching is directly and indirectly driving the decline of South Africa's large population of white rhinos. Anim Conserv 2021. [DOI: 10.1111/acv.12720] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zoliswa N. Nhleko
- Interdisciplinary Program in Ecology University of Florida Gainesville FL USA
- Savanna Node Scientific Services SANParks Skukuza South Africa
| | - Robert Ahrens
- Fisheries and Aquatic Sciences Program University of Florida Gainesville FL USA
- Fisheries Research and Monitoring Division NOAA Pacific Islands Fisheries Science Center Honolulu HI USA
| | - Sam M. Ferreira
- Savanna Node Scientific Services SANParks Skukuza South Africa
| | - Robert A. McCleery
- Department of Wildlife Ecology and Conservation University of Florida Gainesville FL USA
| |
Collapse
|
18
|
Kardos M, Luikart G. The Genetic Architecture of Fitness Drives Population Viability during Rapid Environmental Change. Am Nat 2021; 197:511-525. [DOI: 10.1086/713469] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
19
|
Morrison TA, Merkle JA, Hopcraft JGC, Aikens EO, Beck JL, Boone RB, Courtemanch AB, Dwinnell SP, Fairbanks WS, Griffith B, Middleton AD, Monteith KL, Oates B, Riotte-Lambert L, Sawyer H, Smith KT, Stabach JA, Taylor KL, Kauffman MJ. Drivers of site fidelity in ungulates. J Anim Ecol 2021; 90:955-966. [PMID: 33481254 DOI: 10.1111/1365-2656.13425] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 11/28/2020] [Indexed: 01/26/2023]
Abstract
While the tendency to return to previously visited locations-termed 'site fidelity'-is common in animals, the cause of this behaviour is not well understood. One hypothesis is that site fidelity is shaped by an animal's environment, such that animals living in landscapes with predictable resources have stronger site fidelity. Site fidelity may also be conditional on the success of animals' recent visits to that location, and it may become stronger with age as the animal accumulates experience in their landscape. Finally, differences between species, such as the way memory shapes site attractiveness, may interact with environmental drivers to modulate the strength of site fidelity. We compared inter-year site fidelity in 669 individuals across eight ungulate species fitted with GPS collars and occupying a range of environmental conditions in North America and Africa. We used a distance-based index of site fidelity and tested hypothesized drivers of site fidelity using linear mixed effects models, while accounting for variation in annual range size. Mule deer Odocoileus hemionus and moose Alces alces exhibited relatively strong site fidelity, while wildebeest Connochaetes taurinus and barren-ground caribou Rangifer tarandus granti had relatively weak fidelity. Site fidelity was strongest in predictable landscapes where vegetative greening occurred at regular intervals over time (i.e. high temporal contingency). Species differed in their response to spatial heterogeneity in greenness (i.e. spatial constancy). Site fidelity varied seasonally in some species, but remained constant over time in others. Elk employed a 'win-stay, lose-switch' strategy, in which successful resource tracking in the springtime resulted in strong site fidelity the following spring. Site fidelity did not vary with age in any species tested. Our results provide support for the environmental hypothesis, particularly that regularity in vegetative phenology shapes the strength of site fidelity at the inter-annual scale. Large unexplained differences in site fidelity suggest that other factors, possibly species-specific differences in attraction to known sites, contribute to variation in the expression of this behaviour. Understanding drivers of variation in site fidelity across groups of organisms living in different environments provides important behavioural context for predicting how animals will respond to environmental change.
Collapse
Affiliation(s)
- Thomas A Morrison
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Jerod A Merkle
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | - J Grant C Hopcraft
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Ellen O Aikens
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
| | - Jeffrey L Beck
- Department of Ecosystem Science and Management, University of Wyoming, Laramie, WY, USA
| | - Randall B Boone
- Department of Ecosystem Science and Sustainability and the Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, USA
| | | | - Samantha P Dwinnell
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | - W Sue Fairbanks
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, USA
| | - Brad Griffith
- U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Arthur D Middleton
- Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Kevin L Monteith
- Wyoming Cooperative Fish and Wildlife Research Unit, University of Wyoming, Laramie, WY, USA.,Department of Zoology and Physiology & Haub School of Environment and Natural Resources, University of Wyoming, Laramie, WY, USA
| | - Brendan Oates
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | - Louise Riotte-Lambert
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Hall Sawyer
- Western Ecosystems Technology, Inc, Laramie, WY, USA
| | - Kurt T Smith
- Department of Ecosystem Science and Management, University of Wyoming, Laramie, WY, USA
| | - Jared A Stabach
- Smithsonian Conservation Biology Institute, Conservation Ecology Center, National Zoological Park, Front Royal, VA, USA
| | | | - Matthew J Kauffman
- U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| |
Collapse
|
20
|
Morin A, Chamaillé-Jammes S, Valeix M. Climate Effects on Prey Vulnerability Modify Expectations of Predator Responses to Short- and Long-Term Climate Fluctuations. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2020.601202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Climate changes affect the distribution and abundance of organisms, often via changes in species interactions. Most animals experience predation, and a number of models have investigated how climate fluctuations can influence predator–prey dynamics by affecting prey abundance through changes in resource availability. However, field studies have shown that prey vulnerability is a key feature determining the outcome of predator–prey interactions, which also varies with climatic conditions, via changes in prey body condition or in habitat characteristics (e.g. vegetation cover). In this theoretical work, we explore, with large mammals of African savannas in mind, how the interplay between climate-induced changes in prey abundance and climate-induced changes in prey vulnerability affects the immediate and long-term responses of predator populations. We account for prey body condition and habitat effects on prey vulnerability to predation. We show that predictions on how predator abundance responds to climate fluctuations differ depending on how climate influences prey vulnerability (habitat characteristics vs. prey body condition). We discuss how species traits influence the relative importance of the different sources of vulnerability. For example, our results suggest that populations of cursorial predators (such as spotted hyaenas) are expected to fare better than populations of ambush predators (such as African lions) in African ecosystems that will be characterised by an aridification. This study highlights the importance of understanding, and accounting for, the vulnerability factors associated to a given predator–prey pair, and improves our comprehension of predator–prey relationships in a changing climate.
Collapse
|
21
|
Handler KS, Subalusky AL, Kendall CJ, Dutton CL, Rosi EJ, Post DM. Temporal resource partitioning of wildebeest carcasses by scavengers after riverine mass mortality events. Ecosphere 2021. [DOI: 10.1002/ecs2.3326] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Katherine S. Handler
- Department of Ecology and Evolutionary Biology Yale University New Haven Connecticut06511USA
| | - Amanda L. Subalusky
- Department of Ecology and Evolutionary Biology Yale University New Haven Connecticut06511USA
- Department of Biology University of Florida Gainesville Florida32611USA
| | - Corinne J. Kendall
- North Carolina Zoo Asheboro North Carolina27205USA
- North Carolina State University Raleigh North Carolina27607USA
| | - Christopher L. Dutton
- Department of Ecology and Evolutionary Biology Yale University New Haven Connecticut06511USA
- Department of Biology University of Florida Gainesville Florida32611USA
| | - Emma J. Rosi
- Cary Institute of Ecosystem Studies Millbrook New York12545USA
| | - David M. Post
- Department of Ecology and Evolutionary Biology Yale University New Haven Connecticut06511USA
| |
Collapse
|
22
|
Gutiérrez R, Córdova-Lepe F, Moreno-Gómez FN, Velásquez NA. Persistence and size of seasonal populations on a consumer-resource relationship depends on the allocation strategy toward life-history functions. Sci Rep 2020; 10:21401. [PMID: 33293662 PMCID: PMC7722923 DOI: 10.1038/s41598-020-77326-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/27/2020] [Indexed: 11/09/2022] Open
Abstract
The long-term ecological dynamics of a population inhabiting a seasonal environment is analyzed using a semi-discrete or impulsive system to represent the consumer-resource interaction. The resource corresponds to an incoming energy flow for consumers that is allocated to reproduction as well as to maintenance in each non-reproductive season. The energy invested in these life-history functions is used in reproductive events, determining the size of the offspring in each reproductive season. Two long-term dynamic patterns are found, resulting in either the persistence or the extinction of the population of consumers. In addition, our model indicates that only one energy allocation strategy provides an optimal combination between individual consumption and long-term population size. The current study contributes to the understanding of how the individual-level and the population-level are interrelated, exhibiting the importance of incorporating phenotypic traits in population dynamics.
Collapse
Affiliation(s)
- Rodrigo Gutiérrez
- Doctorado en Modelamiento Matemático Aplicado, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile. .,Laboratorio de Comunicación Animal, Departamento de Biología y Química, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile. .,Facultad de Ciencias Básicas, Departamento de Matemática, Física y Estadística, Universidad Católica del Maule, Talca, Chile.
| | - Fernando Córdova-Lepe
- Doctorado en Modelamiento Matemático Aplicado, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile.,Facultad de Ciencias Básicas, Departamento de Matemática, Física y Estadística, Universidad Católica del Maule, Talca, Chile
| | - Felipe N Moreno-Gómez
- Doctorado en Modelamiento Matemático Aplicado, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile.,Laboratorio de Bioacústica y Ecología del Comportamiento Animal, Departamento de Biología y Química, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile
| | - Nelson A Velásquez
- Doctorado en Modelamiento Matemático Aplicado, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile.,Laboratorio de Comunicación Animal, Departamento de Biología y Química, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile
| |
Collapse
|
23
|
Pays O, Blanchard P, Chamaillé‐Jammes S, Valeix M, Loveridge AJ, Macdonald DW, Périquet S, Meer E, Duncan P, Mtare G, Fritz H. Disentangling the roles of bottom‐up and top‐down drivers in the trade‐off between food acquisition and safety in prey with multiple predators. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Olivier Pays
- LETG‐Angers UMR 6554 CNRS Université d'Angers Angers France
- LTSER France Zone Atelier CNRS Hwange Dete Zimbabwe
- REHABS International Research Laboratory CNRS‐Université Lyon 1‐Nelson Mandela University George South Africa
| | - Pierrick Blanchard
- Laboratoire Evolution et Diversité Biologique UMR 5174 CNRS ENSFEA Université Paul Sabatier Toulouse III Toulouse France
| | - Simon Chamaillé‐Jammes
- LTSER France Zone Atelier CNRS Hwange Dete Zimbabwe
- CEFE Univ. MontpellierCNRSEPHEIRDUniversité Paul Valéry Montpellier 3 Montpellier France
- Mammal Research Institute Department of Zoology & Entomology University of Pretoria Pretoria South Africa
| | - Marion Valeix
- LTSER France Zone Atelier CNRS Hwange Dete Zimbabwe
- CNRSUniversité LyonUniversité Lyon 1Laboratoire de Biométrie et Biologie Evolutive UMR 5558 Villeurbanne France
- Wildlife Conservation Research Unit (WildCRU) Zoology Department Oxford UniversityRecanati‐Kaplan Centre Abingdon UK
| | - Andrew J. Loveridge
- Wildlife Conservation Research Unit (WildCRU) Zoology Department Oxford UniversityRecanati‐Kaplan Centre Abingdon UK
| | - David W. Macdonald
- Wildlife Conservation Research Unit (WildCRU) Zoology Department Oxford UniversityRecanati‐Kaplan Centre Abingdon UK
| | - Stéphanie Périquet
- CNRSUniversité LyonUniversité Lyon 1Laboratoire de Biométrie et Biologie Evolutive UMR 5558 Villeurbanne France
| | | | - Patrick Duncan
- LTSER France Zone Atelier CNRS Hwange Dete Zimbabwe
- Centre d'Etudes Biologiques de Chizé UMR 7372 CNRS‐Université de la Rochelle Beauvoir‐sur‐Niort France
| | - Godfrey Mtare
- Parks and Wildlife Management Authority Harare Zimbabwe
| | - Hervé Fritz
- LTSER France Zone Atelier CNRS Hwange Dete Zimbabwe
- REHABS International Research Laboratory CNRS‐Université Lyon 1‐Nelson Mandela University George South Africa
- CNRSUniversité LyonUniversité Lyon 1Laboratoire de Biométrie et Biologie Evolutive UMR 5558 Villeurbanne France
- Sustainability Research Unit Nelson Mandela University George South Africa
| |
Collapse
|
24
|
Staver AC, Hempson GP. Seasonal dietary changes increase the abundances of savanna herbivore species. SCIENCE ADVANCES 2020; 6:6/40/eabd2848. [PMID: 33008899 PMCID: PMC7852399 DOI: 10.1126/sciadv.abd2848] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/14/2020] [Indexed: 06/11/2023]
Abstract
African savannas are home to the world's last great megafaunal communities, but despite ongoing population declines, we only poorly understand the constraints on savanna herbivore abundances. Seasonal diet shifts (except migration) have received little attention, despite a diversity of possible dietary strategies. Here, we first formulate two theoretical models that predict that both mixed feeding and migratory grazing increase population sizes. These predictions are borne out in comprehensive data across African savanna parks: Mixed feeders are the most abundant herbivores in Africa, alongside a few migratory grazer populations. Overall, clear mixed-feeder dominance may reflect a historical pattern or may instead mirror a general global decline in specialists. Regardless, mixed feeders dominate the savannas of the present and future.
Collapse
Affiliation(s)
- A Carla Staver
- Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA.
| | - Gareth P Hempson
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
- South African Environmental Observation Network (SAEON), Ndlovu Node, Phalaborwa Gate, Kruger National Park, South Africa
| |
Collapse
|
25
|
Aikens EO, Monteith KL, Merkle JA, Dwinnell SPH, Fralick GL, Kauffman MJ. Drought reshuffles plant phenology and reduces the foraging benefit of green-wave surfing for a migratory ungulate. GLOBAL CHANGE BIOLOGY 2020; 26:4215-4225. [PMID: 32524724 DOI: 10.1111/gcb.15169] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
To increase resource gain, many herbivores pace their migration with the flush of nutritious plant green-up that progresses across the landscape (termed "green-wave surfing"). Despite concerns about the effects of climate change on migratory species and the critical role of plant phenology in mediating the ability of ungulates to surf, little is known about how drought shapes the green wave and influences the foraging benefits of migration. With a 19 year dataset on drought and plant phenology across 99 unique migratory routes of mule deer (Odocoileus hemionus) in western Wyoming, United States, we show that drought shortened the duration of spring green-up by approximately twofold (2.5 weeks) and resulted in less sequential green-up along migratory routes. We investigated the possibility that some routes were buffered from the effects of drought (i.e., routes that maintained long green-up duration irrespective of drought intensity). We found no evidence of drought-buffered routes. Instead, routes with the longest green-up in non-drought years also were the most affected by drought. Despite phenological changes along the migratory route, mule deer closely followed drought-altered green waves during migration. Migrating deer did not experience a trophic mismatch with the green wave during drought. Instead, the shorter window of green-up caused by drought reduced the opportunity to accumulate forage resources during rapid spring migrations. Our work highlights the synchronization of phenological events as an important mechanism by which climate change can negatively affect migratory species by reducing the temporal availability of key food resources. For migratory herbivores, climate change poses a new and growing threat by altering resource phenology and diminishing the foraging benefit of migration.
Collapse
Affiliation(s)
- Ellen O Aikens
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
- Program in Ecology, University of Wyoming, Laramie, WY, USA
| | - Kevin L Monteith
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
- Haub School of Environment and Natural Resources, University of Wyoming, Laramie, WY, USA
| | - Jerod A Merkle
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | - Samantha P H Dwinnell
- Haub School of Environment and Natural Resources, University of Wyoming, Laramie, WY, USA
| | | | - Matthew J Kauffman
- U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| |
Collapse
|
26
|
Lachish S, Brandell EE, Craft ME, Dobson AP, Hudson PJ, MacNulty DR, Coulson T. Investigating the Dynamics of Elk Population Size and Body Mass in a Seasonal Environment Using a Mechanistic Integral Projection Model. Am Nat 2020; 196:E23-E45. [PMID: 32673097 DOI: 10.1086/708723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Environmentally mediated changes in body size often underlie population responses to environmental change, yet this is not a universal phenomenon. Understanding when phenotypic change underlies population responses to environmental change is important for obtaining insights and robust predictions of population dynamics in a changing world. We develop a dynamic integral projection model that mechanistically links environmental conditions to demographic rates and phenotypic traits (body size) via changes in resource availability and individual energetics. We apply the model to the northern Yellowstone elk population and explore population responses to changing patterns of seasonality, incorporating the interdependence of growth, demography, and density-dependent processes operating through population feedback on available resources. We found that small changes in body size distributions can have large impacts on population dynamics but need not cause population responses to environmental change. Environmental changes that altered demographic rates directly, via increasing or decreasing resource availability, led to large population impacts in the absence of substantial changes to body size distributions. In contrast, environmentally driven shifts in body size distributions could occur with little consequence for population dynamics when the effect of environmental change on resource availability was small and seasonally restricted and when strong density-dependent processes counteracted expected population responses. These findings highlight that a robust understanding of how associations between body size and demography influence population responses to environmental change will require knowledge of the shape of the relationship between phenotypic distributions and vital rates, the population status with regard to its carrying capacity, and importantly the nature of the environmentally driven change in body size and carrying capacity.
Collapse
|
27
|
Weeber J, Hempson GP, February EC. Large herbivore conservation in a changing world: Surface water provision and adaptability allow wildebeest to persist after collapse of long-range movements. GLOBAL CHANGE BIOLOGY 2020; 26:2841-2853. [PMID: 32069369 DOI: 10.1111/gcb.15044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 12/24/2019] [Accepted: 02/01/2020] [Indexed: 06/10/2023]
Abstract
Large herbivores, particularly wide-ranging species, are extensively impacted by land use transformation and other anthropogenic barriers to movement. The adaptability of a species is, therefore, crucial to determining whether populations can persist in ever smaller subsets of their historical home ranges. Access to water, by drinking or from forage moisture, is an essential requirement, and surface water provision is thus a long-established, although controversial, conservation practice. In the arid Kgalagadi Transfrontier Park (KTP), South Africa, surface water provision in the 1930s facilitated the establishment of a sedentary wildebeest (Connochaetes taurinus) population in a region historically accessed only in the wet season, via now collapsed long-distance movements. Here, we investigate the behaviour and diet of this wildebeest population, and how these relate to water in the landscape, to better understand the process of transitioning from a mobile to sedentary population. Data from 26 monthly surveys reveal that wildebeest distributions are shaped by water availability and salinity, shade, forage, season and possibly predator detectability. Areas with saline or no water are used predominantly in the wet season when forage moisture is high. Wet season movements beyond the study area mean the timing of wildebeest grazing in these regions matches historical timing. Grass utilization field data suggest that the KTP grazer population experiences forage deficits during the dry season, when ~80% of grass tufts are grazed and C:N and crude protein levels decline. Nonetheless, dung isotope data show that wildebeest meet their crude protein intake requirements during the dry season, likely by consuming unprecedentedly high levels of browse (>33%). While restoring the full historical range and movements of most large herbivore populations is not possible, these findings highlight that understanding the behavioural and dietary adaptability of a species can augment 'next best' efforts to conserve viable populations while home ranges contract.
Collapse
Affiliation(s)
- Joshua Weeber
- Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
- Department of Environmental and Geographical Sciences, University of Cape Town, Cape Town, South Africa
| | - Gareth P Hempson
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
- South African Environmental Observation Network (SAEON), Ndlovu Node, Phalaborwa Gate, South Africa
| | - Edmund C February
- Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
28
|
Kasiringua E, Procheş Ş, Kopij G. Long-Term Population Dynamics of African Ungulates in Waterberg Plateau National Park, Namibia. POLISH JOURNAL OF ECOLOGY 2020. [DOI: 10.3161/15052249pje2019.67.4.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Evert Kasiringua
- Discipline of Geography, University of KwaZulu-Natal, Westville Campus, PB X54001, Durban 4000, South Africa
| | - Şerban Procheş
- Discipline of Geography, University of KwaZulu-Natal, Westville Campus, PB X54001, Durban 4000, South Africa
| | - Grzegorz Kopij
- Department of Integrated Environmental Science, University of Namibia, Ogongo Campus, Private Bag 5520 Oshakati, Namibia
| |
Collapse
|
29
|
Jessop TS, Ariefiandy A, Forsyth DM, Purwandana D, White CR, Benu YJ, Madsen T, Harlow HJ, Letnic M. Komodo dragons are not ecological analogs of apex mammalian predators. Ecology 2020; 101:e02970. [DOI: 10.1002/ecy.2970] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 10/03/2019] [Accepted: 12/04/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Tim S. Jessop
- School of Life and Environmental Sciences Centre for Integrative Ecology Deakin University Waurn Ponds Victoria 3220 Australia
| | | | - David M. Forsyth
- New South Wales Department of Primary Industries Vertebrate Pest Research Unit Orange New South Wales 2800 Australia
| | | | - Craig R. White
- School of Biological Sciences Monash University Clayton Victoria 3800 Australia
| | | | - Thomas Madsen
- School of Life and Environmental Sciences Centre for Integrative Ecology Deakin University Waurn Ponds Victoria 3220 Australia
| | - Henry J. Harlow
- Department of Physiology and Zoology University of Wyoming Laramie Wyoming 82071 USA
| | - Mike Letnic
- School of Biological, Earth and Environmental Sciences Centre for Ecosystem Science University of New South Wales Kensington New South Wales 2033 Australia
| |
Collapse
|
30
|
Kidwai Z, Jimenez J, Louw CJ, Nel H, Marshal JP. Using N-mixture models to estimate abundance and temporal trends of black rhinoceros (Diceros bicornis L.) populations from aerial counts. Glob Ecol Conserv 2019. [DOI: 10.1016/j.gecco.2019.e00687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
|
31
|
Omotoriogun TC, Tende T, Adeiza ZO, Onoja JD, Karau S, Mwansat GS, Ottosson U, Manu SA. Large mammals and wetland utilisation: A case study in Yankari Game Reserve, Nigeria. Afr J Ecol 2019. [DOI: 10.1111/aje.12638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Taiwo C. Omotoriogun
- A. P. Leventis Ornithological Research Institute University of Jos Jos Nigeria
- Biotechnology Unit, Department of Biological Sciences Elizade University Ilara‐Mokin Nigeria
| | - Talatu Tende
- A. P. Leventis Ornithological Research Institute University of Jos Jos Nigeria
| | - Zainab O. Adeiza
- A. P. Leventis Ornithological Research Institute University of Jos Jos Nigeria
- Department of Biological Sciences Baze University Abuja Nigeria
| | - Joseph D. Onoja
- A. P. Leventis Ornithological Research Institute University of Jos Jos Nigeria
- Nigerian Conservation Foundation Lekki, Lagos Nigeria
| | - Shomboro Karau
- A. P. Leventis Ornithological Research Institute University of Jos Jos Nigeria
- National Centre for Remote Sensing Jos Nigeria
| | - Georgina S. Mwansat
- A. P. Leventis Ornithological Research Institute University of Jos Jos Nigeria
| | - Ulf Ottosson
- A. P. Leventis Ornithological Research Institute University of Jos Jos Nigeria
| | - Shiiwua A. Manu
- A. P. Leventis Ornithological Research Institute University of Jos Jos Nigeria
| |
Collapse
|
32
|
Dutton CL, Subalusky AL, Hill TD, Aleman JC, Rosi EJ, Onyango KB, Kanuni K, Cousins JA, Staver AC, Post DM. A 2000-year sediment record reveals rapidly changing sedimentation and land use since the 1960s in the Upper Mara-Serengeti Ecosystem. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 664:148-160. [PMID: 30739850 DOI: 10.1016/j.scitotenv.2019.01.421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/29/2019] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Abstract
The Mara River basin is a trans-boundary basin of international importance. It forms the headwaters of the Nile River and serves as the primary dry season water source for an estimated 1.1 million rural people and the largest remaining overland migration of 1.4 million wildebeest in the Serengeti-Mara Ecosystem. Changes throughout the basin are impacting the quantity and quality of the Mara River, yet the historical context of environmental conditions in the basin is not well known. We collected sediment cores throughout the wetland at the mouth of the Mara River, and we used isotopic dating methods and a suite of analyses to examine historical patterns of sediment quantity and source, mercury contamination, and carbon and nutrient loading. Our results show that ecological conditions in the Mara River basin were fairly stable over paleoecological time scales (2000-1000 years before present), but there has been a period of rapid change in the basin over the last 250 years, particularly since the 1960s. A shift in the source and quantity of sediments in the river began in the late 1700s and became much more pronounced in the 1950s and 1960s, coincident with increasing mercury concentrations. The quantity of sediment from the Upper Mara increased, particularly since 1960, but the proportion of total sediment from this region decreased as the Talek and Middle Mara portions of the basin began producing more sediment. The decadal oscillation in sediment accumulation was congruent with known periods of extreme precipitation events. Carbon and nitrogen loading also increased since the 1960s, and the shift in the isotopic ratio of nitrogen provides evidence for increased anthropogenic loading. Altogether, these data likely reflect patterns of change also experienced in other basins throughout East Africa.
Collapse
Affiliation(s)
- Christopher L Dutton
- Yale University, Department of Ecology and Evolutionary Biology, 165 Prospect St, New Haven, CT 06511, USA.
| | - Amanda L Subalusky
- Cary Institute of Ecosystem Studies, 2801 Sharon Turnpike, Millbrook, NY 12545, USA
| | - Troy D Hill
- South Florida Natural Resources Center, National Park Service, 950 N. Krome Avenue, Homestead, FL 33030, USA
| | - Julie C Aleman
- Yale University, Department of Ecology and Evolutionary Biology, 165 Prospect St, New Haven, CT 06511, USA
| | - Emma J Rosi
- Cary Institute of Ecosystem Studies, 2801 Sharon Turnpike, Millbrook, NY 12545, USA
| | | | - Kanuni Kanuni
- WWF-Tanzania, Plot No. 350, Regent Estate Mikocheni, Dar es Salaam, Tanzania
| | - Jenny A Cousins
- WWF-UK, The Living Planet Centre, Rufford House, Brewery Rd, Woking GU21 4LL, UK
| | - A Carla Staver
- Yale University, Department of Ecology and Evolutionary Biology, 165 Prospect St, New Haven, CT 06511, USA
| | - David M Post
- Yale University, Department of Ecology and Evolutionary Biology, 165 Prospect St, New Haven, CT 06511, USA
| |
Collapse
|
33
|
Veldhuis MP, Ritchie ME, Ogutu JO, Morrison TA, Beale CM, Estes AB, Mwakilema W, Ojwang GO, Parr CL, Probert J, Wargute PW, Hopcraft JGC, Olff H. Cross-boundary human impacts compromise the Serengeti-Mara ecosystem. Science 2019; 363:1424-1428. [DOI: 10.1126/science.aav0564] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 02/28/2019] [Indexed: 01/08/2023]
Abstract
Protected areas provide major benefits for humans in the form of ecosystem services, but landscape degradation by human activity at their edges may compromise their ecological functioning. Using multiple lines of evidence from 40 years of research in the Serengeti-Mara ecosystem, we find that such edge degradation has effectively “squeezed” wildlife into the core protected area and has altered the ecosystem’s dynamics even within this 40,000-square-kilometer ecosystem. This spatial cascade reduced resilience in the core and was mediated by the movement of grazers, which reduced grass fuel and fires, weakened the capacity of soils to sequester nutrients and carbon, and decreased the responsiveness of primary production to rainfall. Similar effects in other protected ecosystems worldwide may require rethinking of natural resource management outside protected areas.
Collapse
Affiliation(s)
| | - Mark E. Ritchie
- Syracuse University, 107 College Place, Syracuse, NY 13244, USA
| | - Joseph O. Ogutu
- University of Hohenheim, Fruwirthstrasse 23, 70599 Stuttgart, Germany
| | | | | | - Anna B. Estes
- Pennsylvania State University, University Park, PA 16802, USA
- The Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | | | - Gordon O. Ojwang
- University of Groningen, Nijenborg 7, 9747AG Groningen, Netherlands
- Directorate of Resource Surveys and Remote Sensing, P.O. Box 47146-00100, Nairobi, Kenya
| | - Catherine L. Parr
- University of Liverpool, Liverpool L69 3GO, UK
- University of the Witwatersrand, Wits 2050, Johannesburg, South Africa
- University of Pretoria, Pretoria 0002, South Africa
| | | | - Patrick W. Wargute
- Directorate of Resource Surveys and Remote Sensing, P.O. Box 47146-00100, Nairobi, Kenya
| | | | - Han Olff
- University of Groningen, Nijenborg 7, 9747AG Groningen, Netherlands
| |
Collapse
|
34
|
Torney CJ, Lloyd‐Jones DJ, Chevallier M, Moyer DC, Maliti HT, Mwita M, Kohi EM, Hopcraft GC. A comparison of deep learning and citizen science techniques for counting wildlife in aerial survey images. Methods Ecol Evol 2019. [DOI: 10.1111/2041-210x.13165] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Colin J. Torney
- School of Mathematics and StatisticsUniversity of Glasgow Glasgow UK
| | - David J. Lloyd‐Jones
- FitzPatrick Institute of African OrnithologyDST‐NRF Centre of ExcellenceUniversity of Cape Town Rondebosch South Africa
| | - Mark Chevallier
- School of Mathematics and StatisticsUniversity of Glasgow Glasgow UK
| | - David C. Moyer
- Integrated Research CenterThe Field Museum of Natural History Chicago Illinois
| | | | - Machoke Mwita
- Tanzania Wildlife Research Institute Arusha Tanzania
| | | | - Grant C. Hopcraft
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of Glasgow Glasgow UK
| |
Collapse
|
35
|
Mann DH, Groves P, Gaglioti BV, Shapiro BA. Climate-driven ecological stability as a globally shared cause of Late Quaternary megafaunal extinctions: the Plaids and Stripes Hypothesis. Biol Rev Camb Philos Soc 2019; 94:328-352. [PMID: 30136433 PMCID: PMC7379602 DOI: 10.1111/brv.12456] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 07/14/2018] [Accepted: 07/19/2018] [Indexed: 01/24/2023]
Abstract
Controversy persists about why so many large-bodied mammal species went extinct around the end of the last ice age. Resolving this is important for understanding extinction processes in general, for assessing the ecological roles of humans, and for conserving remaining megafaunal species, many of which are endangered today. Here we explore an integrative hypothesis that asserts that an underlying cause of Late Quaternary megafaunal extinctions was a fundamental shift in the spatio-temporal fabric of ecosystems worldwide. This shift was triggered by the loss of the millennial-scale climate fluctuations that were characteristic of the ice age but ceased approximately 11700 years ago on most continents. Under ice-age conditions, which prevailed for much of the preceding 2.6 Ma, these radical and rapid climate changes prevented many ecosystems from fully equilibrating with their contemporary climates. Instead of today's 'striped' world in which species' ranges have equilibrated with gradients of temperature, moisture, and seasonality, the ice-age world was a disequilibrial 'plaid' in which species' ranges shifted rapidly and repeatedly over time and space, rarely catching up with contemporary climate. In the transient ecosystems that resulted, certain physiological, anatomical, and ecological attributes shared by megafaunal species pre-adapted them for success. These traits included greater metabolic and locomotory efficiency, increased resistance to starvation, longer life spans, greater sensory ranges, and the ability to be nomadic or migratory. When the plaid world of the ice age ended, many of the advantages of being large were either lost or became disadvantages. For instance in a striped world, the low population densities and slow reproductive rates associated with large body size reduced the resiliency of megafaunal species to population bottlenecks. As the ice age ended, the downsides of being large in striped environments lowered the extinction thresholds of megafauna worldwide, which then increased the vulnerability of individual species to a variety of proximate threats they had previously tolerated, such as human predation, competition with other species, and habitat loss. For many megafaunal species, the plaid-to-stripes transition may have been near the base of a hierarchy of extinction causes whose relative importances varied geographically, temporally, and taxonomically.
Collapse
Affiliation(s)
- Daniel H. Mann
- Department of Geosciences and Institute of Arctic BiologyUniversity of AlaskaFairbanksAK 99775USA
| | - Pamela Groves
- Institute of Arctic BiologyUniversity of AlaskaFairbanksAK 99775USA
| | | | - Beth A. Shapiro
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaSanta CruzCA 95064USA
| |
Collapse
|
36
|
Nkwabi AK, Metzger K, Beyers R, Magige F, Mduma SAR, Hopcraft JGC, Sinclair ARE. Bird community responses to changes in vegetation caused by increasing large mammal populations in the Serengeti woodlands. WILDLIFE RESEARCH 2019. [DOI: 10.1071/wr18001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
The increase in density of large tree species, Vachellia robusta and V. tortilis, in the Serengeti Ecosystem of Tanzania has resulted in a decline of small tree species Senegalia senegal, V. hockii, Commiphora spp. This change has occurred since the late 1970s, a consequence of an increase in wildebeest following the extirpation of rinderpest, which reduced the dry grass fuel for fires, resulting in low fire frequencies. Change in tree species raises the question of whether there are indirect consequences for the avifauna that depend on the large trees for food and nesting.
Aims
To determine how an increase in large mammals could influence diversity and distribution of avifauna communities in the Serengeti ecosystem woodlands.
Methods
Data used to estimate changes in density of large and small trees were measured by Point Centre Quarter (PCQ). Bird species were recorded in 19 small-tree sites and 18 large-tree sites in the Serengeti National Park. Richness of bird guilds was calculated in the two habitat complexes (small and large trees), and the ‘rarefaction’ method was used to assess the difference in richness in habitats of the study area. Mean abundance for each species was calculated over the total number of sites for each habitat and compared using the Wilcoxon Rank Sum test to examine how the abundance of avifauna changes with each habitat type.
Key results
There was an increase in the density of large trees in some areas in which they have replaced the original small trees. Such changes have resulted in greater richness of hole nesters and bark feeders, and a greater abundance of large-hole nesters and gleaner bird species.
Conclusions
Because the increase in tree density was caused by an increase in large mammals, we conclude that this increasing mammal population is indirectly increasing richness and abundance of birds using the trees.
Implications
Understanding the influence of large mammal populations on bird distributions has important conservation implications because the Serengeti ecosystem is classified as an important, endemic bird area.
Collapse
|
37
|
Cunningham CX, Johnson CN, Barmuta LA, Hollings T, Woehler EJ, Jones ME. Top carnivore decline has cascading effects on scavengers and carrion persistence. Proc Biol Sci 2018; 285:rspb.2018.1582. [PMID: 30487308 DOI: 10.1098/rspb.2018.1582] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 11/05/2018] [Indexed: 01/24/2023] Open
Abstract
Top carnivores have suffered widespread global declines, with well-documented effects on mesopredators and herbivores. We know less about how carnivores affect ecosystems through scavenging. Tasmania's top carnivore, the Tasmanian devil (Sarcophilus harrisii), has suffered severe disease-induced population declines, providing a natural experiment on the role of scavenging in structuring communities. Using remote cameras and experimentally placed carcasses, we show that mesopredators consume more carrion in areas where devils have declined. Carcass consumption by the two native mesopredators was best predicted by competition for carrion, whereas consumption by the invasive mesopredator, the feral cat (Felis catus), was better predicted by the landscape-level abundance of devils, suggesting a relaxed landscape of fear where devils are suppressed. Reduced discovery of carcasses by devils was balanced by the increased discovery by mesopredators. Nonetheless, carcasses persisted approximately 2.6-fold longer where devils have declined, highlighting their importance for rapid carrion removal. The major beneficiary of increased carrion availability was the forest raven (Corvus tasmanicus). Population trends of ravens increased 2.2-fold from 1998 to 2017, the period of devil decline, but this increase occurred Tasmania-wide, making the cause unclear. This case study provides a little-studied potential mechanism for mesopredator release, with broad relevance to the vast areas of the world that have suffered carnivore declines.
Collapse
Affiliation(s)
- Calum X Cunningham
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Christopher N Johnson
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia.,Australian Research Council Centre for Australian Biodiversity and Heritage, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Leon A Barmuta
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Tracey Hollings
- Department of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria 3084, Australia.,Centre of Excellence for Biosecurity Risk Analysis, School of Biosciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Eric J Woehler
- Birdlife Tasmania, GPO Box 68, Hobart, Tasmania, Australia
| | - Menna E Jones
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia
| |
Collapse
|
38
|
Bartzke GS, Ogutu JO, Mukhopadhyay S, Mtui D, Dublin HT, Piepho HP. Rainfall trends and variation in the Maasai Mara ecosystem and their implications for animal population and biodiversity dynamics. PLoS One 2018; 13:e0202814. [PMID: 30231048 PMCID: PMC6145597 DOI: 10.1371/journal.pone.0202814] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 08/09/2018] [Indexed: 11/19/2022] Open
Abstract
Rainfall exerts a controlling influence on the availability and quality of vegetation and surface water for herbivores in African terrestrial ecosystems. We analyse temporal trends and variation in rainfall in the Maasai Mara ecosystem of East Africa and infer their implications for animal population and biodiversity dynamics. The data originated from 15 rain gauges in the Mara region (1965–2015) and one station in Narok Town (1913–2015), in Kenya’s Narok County. This is the first comprehensive and most detailed analysis of changes in rainfall in the region of its kind. Our results do not support the current predictions of the International Panel of Climate Change (IPCC) of very likely increases of rainfall over parts of Eastern Africa. The dry season rainfall component increased during 1935–2015 but annual rainfall decreased during 1962–2015 in Narok Town. Monthly rainfall was more stable and higher in the Mara than in Narok Town, likely because the Mara lies closer to the high-precipitation areas along the shores of Lake Victoria. Predominantly deterministic and persistent inter-annual cycles and extremely stable seasonal rainfall oscillations characterize rainfall in the Mara and Narok regions. The frequency of severe droughts increased and floods intensified in the Mara but droughts became less frequent and less severe in Narok Town. The timings of extreme droughts and floods coincided with significant periodicity in rainfall oscillations, implicating strong influences of global atmospheric and oceanic circulation patterns on regional rainfall variability. These changing rainfall patterns have implications for animal population dynamics. The increase in dry season rainfall during 1935–2015 possibly counterbalanced the impacts of resource scarcity generated by the declining annual rainfall during 1965–2015 in Narok Town. However, the increasing rainfall extremes in the Mara can be expected to create conditions conducive to outbreaks of infectious animal diseases and reduced vegetation quality for herbivores, particularly when droughts and floods persist over multiple years. The more extreme wet season rainfall may also alter herbivore space use, including migration patterns.
Collapse
Affiliation(s)
- Gundula S. Bartzke
- Biostatistics Unit, Institute of Crop Science, University of Hohenheim, Stuttgart, Germany
- * E-mail:
| | - Joseph O. Ogutu
- Biostatistics Unit, Institute of Crop Science, University of Hohenheim, Stuttgart, Germany
| | | | - Devolent Mtui
- Directorate of Research, Tanzania Wildlife Research Institute, Arusha, Tanzania
| | - Holly T. Dublin
- Wasaa Conservation Centre, IUCN Eastern and Southern Africa Regional Office, Nairobi, Kenya
| | - Hans-Peter Piepho
- Biostatistics Unit, Institute of Crop Science, University of Hohenheim, Stuttgart, Germany
| |
Collapse
|
39
|
Calabrese JM, Moss Clay A, Estes RD, Thompson KV, Monfort SL. Male rutting calls synchronize reproduction in Serengeti wildebeest. Sci Rep 2018; 8:10202. [PMID: 29976996 PMCID: PMC6033926 DOI: 10.1038/s41598-018-28307-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 06/08/2018] [Indexed: 11/08/2022] Open
Abstract
Tightly synchronized reproduction in vast wildebeest herds underpins the keystone role this iconic species plays in the Serengeti. However, despite decades of study, the proximate synchronizing mechanism remains unknown. Combining a season-long field experiment with simple stochastic process models, we show that females exposed to playback of male rutting vocalizations are over three times more synchronous in their expected time to mating than a control group isolated from all male stimuli. Additionally, predictions of both mating and calving synchrony based on the playback group were highly consistent with independent data on wildebeest mating and calving synchrony, while control-based predictions were inconsistent with the data. Taken together, our results provide the first experimental evidence that male rutting vocalizations alone could account for the highly synchronized reproduction observed in Serengeti wildebeest. Given anthropogenically driven losses in many areas, a mechanistic understanding of synchrony can highlight additional risks declining wildebeest populations may face.
Collapse
Affiliation(s)
- Justin M Calabrese
- Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Road, Front Royal, VA, 22630, USA.
| | - Allison Moss Clay
- Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Road, Front Royal, VA, 22630, USA.
| | - Richard D Estes
- Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Road, Front Royal, VA, 22630, USA
| | - Katerina V Thompson
- College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD, 20742, USA
| | - Steven L Monfort
- Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Road, Front Royal, VA, 22630, USA
| |
Collapse
|
40
|
Hebblewhite M, Eacker DR, Eggeman S, Bohm H, Merrill EH. Density-independent predation affects migrants and residents equally in a declining partially migratory elk population. OIKOS 2018. [DOI: 10.1111/oik.05304] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mark Hebblewhite
- Wildlife Biology Program, Dept of Ecosystem and Conservation Sciences; W. A. Franke College of Forestry and Conservation, Univ. of Montana; 32 Campus Drive Missoula MT 59812 USA
| | - Daniel R. Eacker
- Wildlife Biology Program, Dept of Ecosystem and Conservation Sciences; W. A. Franke College of Forestry and Conservation, Univ. of Montana; 32 Campus Drive Missoula MT 59812 USA
| | - Scott Eggeman
- Wildlife Biology Program, Dept of Ecosystem and Conservation Sciences; W. A. Franke College of Forestry and Conservation, Univ. of Montana; 32 Campus Drive Missoula MT 59812 USA
| | - Holger Bohm
- Dept of Biological Sciences; Univ. of Alberta; Edmonton AB Canada
| | | |
Collapse
|
41
|
Ali AH, Kauffman MJ, Amin R, Kibara A, King J, Mallon D, Musyoki C, Goheen JR. Demographic drivers of a refugee species: large-scale experiments guide strategies for reintroductions of hirola. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:275-283. [PMID: 29222956 DOI: 10.1002/eap.1664] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 09/28/2017] [Accepted: 10/02/2017] [Indexed: 06/07/2023]
Abstract
Effective reintroduction strategies require accurate estimates of vital rates and the factors that influence them. The hirola (Beatragus hunteri) is the rarest antelope on Earth, with a global population size of <500 individuals restricted to the Kenya-Somali border. We estimated vital rates of hirola populations exposed to varying levels of predation and rangeland quality from 2012 to 2015, and then built population matrices to estimate the finite rate of population change (λ) and demographic sensitivities. Mean survival for all age classes and population growth was highest in the low-predation-high-rangeland-quality setting (λ = 1.08 ± 0.03 [mean ± SE]), and lowest in the high-predation-low-rangeland-quality setting (λ = 0.70 ± 0.22). Retrospective demographic analyses revealed that increased fecundity (the number of female calves born to adult females annually) and female calf survival were responsible for higher population growth where large carnivores were absent. In contrast, variation in adult female survival was the primary contributor to differences in population growth attributable to rangeland quality. Our analyses suggest that hirola demography is driven by a combination of top-down (predation) and bottom-up (rangeland quality) forces, with populations in the contemporary geographic range impacted both by declining rangeland quality and predation. To enhance the chances of successful reintroductions, conservationists can consider rangeland restoration to boost both the survival and fecundity of adult females within the hirola's historical range.
Collapse
Affiliation(s)
- Abdullahi H Ali
- Program in Ecology and Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
- National Museums of Kenya, Nairobi, Kenya
- Hirola Conservation Programme, Garissa, Kenya
| | - Matthew J Kauffman
- Program in Ecology and Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
- U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Laramie, Wyoming, 82071, USA
| | - Rajan Amin
- Conservation Programmes, Zoological Society of London, London, United Kingdom
| | - Amos Kibara
- Hirola Conservation Programme, Garissa, Kenya
| | | | - David Mallon
- IUCN SSP Antelope Specialist Group, Manchester Metropolitan University, Glossop, United Kingdom
| | | | - Jacob R Goheen
- Program in Ecology and Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| |
Collapse
|
42
|
Yeakel JD, Kempes CP, Redner S. Dynamics of starvation and recovery predict extinction risk and both Damuth's law and Cope's rule. Nat Commun 2018; 9:657. [PMID: 29440734 PMCID: PMC5811595 DOI: 10.1038/s41467-018-02822-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 01/02/2018] [Indexed: 11/09/2022] Open
Abstract
The eco-evolutionary dynamics of species are fundamentally linked to the energetic constraints of their constituent individuals. Of particular importance is the interplay between reproduction and the dynamics of starvation and recovery. To elucidate this interplay, here we introduce a nutritional state-structured model that incorporates two classes of consumers: nutritionally replete, reproducing consumers, and undernourished, nonreproducing consumers. We obtain strong constraints on starvation and recovery rates by deriving allometric scaling relationships and find that population dynamics are typically driven to a steady state. Moreover, these rates fall within a "refuge" in parameter space, where the probability of population extinction is minimized. We also show that our model provides a natural framework to predict steady state population abundances known as Damuth's law, and maximum mammalian body size. By determining the relative stability of an otherwise homogeneous population to a competing population with altered percent body fat, this framework provides a principled mechanism for a selective driver of Cope's rule.
Collapse
Affiliation(s)
- Justin D Yeakel
- School of Natural Sciences, University of California, Merced, CA, 95340, USA. .,The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM, 87501, USA.
| | | | - Sidney Redner
- The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM, 87501, USA.
| |
Collapse
|
43
|
Vogel JT, Somers MJ, Venter JA. The foraging ecology of reintroduced African wild dog in small protected areas. WILDLIFE BIOLOGY 2018. [DOI: 10.2981/wlb.00424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- John T. Vogel
- J. T. Vogel and J. A. Venter , School of Natural Resource Management, Faculty of Science, George Campus, Nelson Mandela Univ., South Africa
| | - Michael J. Somers
- M. J. Somers, Centre for Wildlife Management, Mammal Research Inst., Centre for Invasion Biology, Univ. of Pretoria, Pretoria, South Africa
| | - Jan A. Venter
- J. T. Vogel and J. A. Venter , School of Natural Resource Management, Faculty of Science, George Campus, Nelson Mandela Univ., South Africa
| |
Collapse
|
44
|
Ranjeewa AD, Pastorini J, Isler K, Weerakoon DK, Kottage HD, Fernando P. Decreasing reservoir water levels improve habitat quality for Asian elephants. Mamm Biol 2018. [DOI: 10.1016/j.mambio.2017.10.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
45
|
Tyrrell P, Russell S, Western D. Seasonal movements of wildlife and livestock in a heterogenous pastoral landscape: Implications for coexistence and community based conservation. Glob Ecol Conserv 2017. [DOI: 10.1016/j.gecco.2017.08.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
46
|
Root-Bernstein M, Galetti M, Ladle RJ. Rewilding South America: Ten key questions. Perspect Ecol Conserv 2017. [DOI: 10.1016/j.pecon.2017.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
|
47
|
Donohue JG, Piiroinen PT. Protective parenting may have population-level consequences. ECOLOGICAL COMPLEXITY 2017. [DOI: 10.1016/j.ecocom.2017.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
48
|
Soria-Díaz L, Fowler MS, Monroy-Vilchis O. Top-down and bottom-up control on cougar and its prey in a central Mexican natural reserve. EUR J WILDLIFE RES 2017. [DOI: 10.1007/s10344-017-1129-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
49
|
Subalusky AL, Dutton CL, Rosi EJ, Post DM. Annual mass drownings of the Serengeti wildebeest migration influence nutrient cycling and storage in the Mara River. Proc Natl Acad Sci U S A 2017; 114:7647-7652. [PMID: 28630330 PMCID: PMC5530641 DOI: 10.1073/pnas.1614778114] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The annual migration of ∼1.2 million wildebeest (Connochaetes taurinus) through the Serengeti Mara Ecosystem is the largest remaining overland migration in the world. One of the most iconic portions of their migration is crossing of the Mara River, during which thousands drown annually. These mass drownings have been noted, but their frequency, size, and impact on aquatic ecosystems have not been quantified. Here, we estimate the frequency and size of mass drownings in the Mara River and model the fate of carcass nutrients through the river ecosystem. Mass drownings (>100 individuals) occurred in at least 13 of the past 15 y; on average, 6,250 carcasses and 1,100 tons of biomass enter the river each year. Half of a wildebeest carcass dry mass is bone, which takes 7 y to decompose, thus acting as a long-term source of nutrients to the Mara River. Carcass soft tissue decomposes in 2-10 wk, and these nutrients are mineralized by consumers, assimilated by biofilms, transported downstream, or moved back into the terrestrial ecosystem by scavengers. These inputs comprise 34-50% of the assimilated diet of fish when carcasses are present and 7-24% via biofilm on bones after soft tissue decomposition. Our results show a terrestrial animal migration can have large impacts on a river ecosystem, which may influence nutrient cycling and river food webs at decadal time scales. Similar mass drownings may have played an important role in rivers throughout the world when large migratory herds were more common features of the landscape.
Collapse
Affiliation(s)
- Amanda L Subalusky
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511;
- Cary Institute of Ecosystem Studies, Millbrook, NY 12545
| | - Christopher L Dutton
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511
- Cary Institute of Ecosystem Studies, Millbrook, NY 12545
| | - Emma J Rosi
- Cary Institute of Ecosystem Studies, Millbrook, NY 12545
| | - David M Post
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511
| |
Collapse
|
50
|
Witt AB, Kiambi S, Beale T, Van Wilgen BW. A preliminary assessment of the extent and potential impacts of alien plant invasions in the Serengeti-Mara ecosystem, East Africa. KOEDOE: AFRICAN PROTECTED AREA CONSERVATION AND SCIENCE 2017. [DOI: 10.4102/koedoe.v59i1.1426] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
This article provides a preliminary list of alien plant species in the Serengeti-Mara ecosystem in East Africa. The list is based on broad-scale roadside surveys in the area and is supplemented by more detailed surveys of tourist facilities in the Masai-Mara National Reserve and adjoining conservancies. We encountered 245 alien plant species; significantly more than previous studies, of which 62 (25%) were considered to have established self-perpetuating populations in areas away from human habitation. These included species which had either been intentionally or accidentally introduced. Of the 245 alien plants, 212 (including four species considered to be native to the region) were intentionally introduced into gardens in the National Reserve and 51 (24%) had established naturalised populations within the boundaries of these tourism facilities. Of the 51 naturalised species, 23 (11% of the 212 alien species) were recorded as being invasive within the ecosystem, outside of lodges and away from other human habitation. Currently, the Serengeti-Mara ecosystem is relatively free of widespread and abundant invasive alien plants, with a few exceptions, but there are extensive populations outside of the ecosystem, particularly to the west, from where they could spread. We address the potential impacts of six species that we consider to pose the highest risks (Parthenium hysterophorus, Opuntia stricta, Tithonia diversifolia, Lantana camara, Chromolaena odorata and Prosopis juliflora). Although invasive alien plants pose substantial threats to the integrity of the ecosystem, this has not yet been widely recognised. We predict that in the absence of efforts to contain, or reverse the spread of invasive alien plants, the condition of rangelands will deteriorate, with severe negative impacts on migrating large mammals, especially wildebeest, zebra and gazelles. This will, in turn, have a substantial negative impact on tourism, which is a major economic activity in the area.Conservation implications: Invasive alien plants pose significant threats to the integrity of the Serengeti-Mara ecosystem and steps will need to be taken to prevent these impacts. The most important of these would be the removal of alien species from tourist facilities, especially those which are known to be naturalised or invasive, the introduction of control programmes aimed at eliminating outlier invasive plant populations to slow down the spread, and the widespread use of biological control wherever possible.
Collapse
|