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Kojima LV, Kohl MT, Rainwater TR, Parrott BB, Tuberville TD. Association of size, climatic factors, and mercury body burdens with movement behavior in American alligators. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:170859. [PMID: 38365032 DOI: 10.1016/j.scitotenv.2024.170859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 02/18/2024]
Abstract
Animal movement behavior provides insight into organismal and ecological function. These functions are often disturbed by anthropogenic influences, such as urbanization and habitat fragmentation, yet the effects of long-term exposures to environmental contaminants on movement have yet to be examined. The long lifespans and broad diets of crocodilians often lead to bioaccumulation of persistent contaminants and confer a marked vulnerability to consequent physiological effects. In this study, we investigate the relationships between blood concentrations of mercury (Hg), a widespread contaminant with well characterized neurotoxicity, and movement patterns in free living, naturally exposed American alligators (Alligator mississippiensis). We sampled adult male alligators from two former nuclear cooling reservoirs with different Hg contamination histories and placed GPS transmitters on a subset of individuals from each reservoir (13 total). Data collected over the ensuing two years were analyzed using a linear mixed effects framework combined with AICc model selection to resolve the relationships linking seasonal alligator movement (daily activity (s) and daily distance (m)) and home range to climate conditions, individual traits, and blood Hg concentrations (mg/kg; wet weight). We found that climate conditions, alligator size (snout-vent-length), and blood Hg concentrations all influence alligator daily activity but do not contribute to alligator daily movement (distance). Furthermore, we found that blood Hg concentrations were strongly correlated with seasonal home range size where individuals with elevated Hg had larger home ranges in spring, fall, and winter. These findings provide insight into how climate, anthropogenic contaminants, and individual traits relate to alligator movement patterns across seasons.
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Affiliation(s)
- Laura V Kojima
- Savannah River Ecology Laboratory, University of Georgia, P.O. Drawer E, Aiken, SC 29802, USA; Odum School of Ecology, University of Georgia, 140 E Green St, Athens, GA 30602, USA.
| | - Michel T Kohl
- Warnell School of Forestry and Natural Resources, University of Georgia, 180 E Green St, Athens, GA 30602, USA.
| | - Thomas R Rainwater
- Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC, USA; Tom Yawkey Wildlife Center, Georgetown, SC, USA
| | - Benjamin B Parrott
- Savannah River Ecology Laboratory, University of Georgia, P.O. Drawer E, Aiken, SC 29802, USA; Odum School of Ecology, University of Georgia, 140 E Green St, Athens, GA 30602, USA.
| | - Tracey D Tuberville
- Savannah River Ecology Laboratory, University of Georgia, P.O. Drawer E, Aiken, SC 29802, USA.
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Harman RR, Kim TN. Differentiating spillover: an examination of cross-habitat movement in ecology spillover in ecology. Proc Biol Sci 2024; 291:20232707. [PMID: 38351801 PMCID: PMC10865012 DOI: 10.1098/rspb.2023.2707] [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: 12/05/2023] [Accepted: 01/11/2024] [Indexed: 02/16/2024] Open
Abstract
Organisms that immigrate into a recipient habitat generate a movement pattern that affects local population dynamics and the environment. Spillover is the pattern of unidirectional movement from a donor habitat to a different, adjacent recipient habitat. However, ecological definitions are often generalized to include any cross-habitat movement, which limits within- and cross-discipline collaboration. To assess spillover nomenclature, we reviewed 337 studies within the agriculture, disease, fisheries and habitat fragmentation disciplines. Each study's definition of spillover and the methods used were analysed. We identified four descriptors (movement, habitat type and arrangement, and effect) used that differentiate spillover from other cross-habitat movement patterns (dispersal, foray loops and edge movement). Studies often define spillover as movement (45%) but rarely measure it as such (4%), particularly in disease and habitat fragmentation disciplines. Consequently, 98% of studies could not distinguish linear from returning movement out of a donor habitat, which can overestimate movement distance. Overall, few studies (12%) included methods that matched their own definition, revealing a distinct mismatch. Because theory shows that long-term impacts of the different movement patterns can vary, differentiating spillover from other movement patterns is necessary for effective long-term and inter-disciplinary management of organisms that use heterogeneous landscapes.
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Affiliation(s)
- Rachel R. Harman
- Department of Entomology, Kansas State University, 123 W. Waters Hall, Manhattan, KS 66506, USA
| | - Tania N. Kim
- Department of Entomology, Kansas State University, 123 W. Waters Hall, Manhattan, KS 66506, USA
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Humphries NE, Fuller DW, Schaefer KM, Sims DW. Highly active fish in low oxygen environments: vertical movements and behavioural responses of bigeye and yellowfin tunas to oxygen minimum zones in the eastern Pacific Ocean. MARINE BIOLOGY 2024; 171:55. [PMID: 38226137 PMCID: PMC10787700 DOI: 10.1007/s00227-023-04366-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 11/24/2023] [Indexed: 01/17/2024]
Abstract
Oxygen minimum zones in the open ocean are predicted to significantly increase in volume over the coming decades as a result of anthropogenic climatic warming. The resulting reduction in dissolved oxygen (DO) in the pelagic realm is likely to have detrimental impacts on water-breathing organisms, particularly those with higher metabolic rates, such as billfish, tunas, and sharks. However, little is known about how free-living fish respond to low DO environments, and therefore, the effect increasing OMZs will have cannot be predicted reliably. Here, we compare the responses of two active predators (bigeye tuna Thunnus obesus and yellowfin tuna Thunnus albacares) to DO at depth throughout the eastern Pacific Ocean. Using time-series data from 267 tagged tunas (59,910 days) and 3D maps of modelled DO, we find that yellowfin tuna respond to low DO at depth by spending more time in shallower, more oxygenated waters. By contrast, bigeye tuna, which forage at deeper depths well below the thermocline, show fewer changes in their use of the water column. However, we find that bigeye tuna increased the frequency of brief upward vertical excursions they performed by four times when DO at depth was lower, but with no concomitant significant difference in temperature, suggesting that this behaviour is driven in part by the need to re-oxygenate following time spent in hypoxic waters. These findings suggest that increasing OMZs will impact the behaviour of these commercially important species, and it is therefore likely that other water-breathing predators with higher metabolic rates will face similar pressures. A more comprehensive understanding of the effect of shoaling OMZs on pelagic fish vertical habitat use, which may increase their vulnerability to surface fisheries, will be important to obtain if these effects are to be mitigated by future management actions. Supplementary Information The online version contains supplementary material available at 10.1007/s00227-023-04366-2.
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Affiliation(s)
- Nicolas E. Humphries
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB UK
| | - Daniel W. Fuller
- Inter-American Tropical Tuna Commission, La Jolla, San Diego, CA USA
| | - Kurt M. Schaefer
- Inter-American Tropical Tuna Commission, La Jolla, San Diego, CA USA
| | - David W. Sims
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB UK
- Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton, Waterfront Campus, Southampton, SO14 3ZH UK
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De Wysiecki AM, Barnett A, Cortés F, Wiff R, Merlo PJ, Jaureguizar AJ, Awruch CA, Trobbiani GA, Irigoyen AJ. The essential habitat role of a unique coastal inlet for a widely distributed apex predator. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230667. [PMID: 37830021 PMCID: PMC10565395 DOI: 10.1098/rsos.230667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023]
Abstract
Essential habitats support specific functions for species, such as reproduction, feeding or refuge. For highly mobile aquatic species, identifying essential habitats within the wider distribution range is central to understanding species ecology, and underpinning effective management plans. This study examined the movement and space use patterns of sevengill sharks (Notorynchus cepedianus) in Caleta Valdés (CV), a unique coastal habitat in northern Patagonia, Argentina. Seasonal residency patterns of sharks were evident, with higher detectability in late spring and early summer and lower during autumn and winter. The overlap between the residency patterns of sharks and their prey, elephant seals, suggests that CV functions as a seasonal feeding aggregation site for N. cepedianus. The study also found sexual differences in movement behaviour, with males performing abrupt departures from CV and showing increased roaming with the presence of more sharks, and maximum detection probability at high tide. These movements could be related to different feeding strategies between sexes or mate-searching behaviour, suggesting that CV may also be essential for reproduction. Overall, this study highlights the importance of coastal sites as essential habitats for N. cepedianus and deepens our understanding of the ecological role of this apex predator in marine ecosystems.
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Affiliation(s)
- Agustín M. De Wysiecki
- Centro para el Estudio de Sistemas Marinos, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Puerto Madryn, Chubut, Argentina
| | - Adam Barnett
- Marine Data Technology Hub, James Cook University, Townsville, Queensland, Australia
- Biopixel Oceans Foundation, Cairns, Queensland, Australia
| | - Federico Cortés
- Instituto Nacional de Investigación y Desarrollo Pesquero, Mar del Plata, Buenos Aires, Argentina
| | - Rodrigo Wiff
- Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, Santiago, Chile
- Instituto Milenio en Socio-Ecología Costera (SECOS), Santiago, Chile
| | - Pablo J. Merlo
- Centro para el Estudio de Sistemas Marinos, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Puerto Madryn, Chubut, Argentina
| | - Andrés J. Jaureguizar
- Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC), La Plata, Buenos Aires, Argentina
- Instituto Argentino de Oceanografía (IADO), Bahía Blanca, Buenos Aires, Argentina
- Universidad Provincial del Sudoeste (UPSO), Coronel Pringles, Buenos Aires, Argentina
| | - Cynthia A. Awruch
- Centro para el Estudio de Sistemas Marinos, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Puerto Madryn, Chubut, Argentina
- Fisheries and Aquaculture, Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, Tasmania, Australia
| | - Gastón A. Trobbiani
- Centro para el Estudio de Sistemas Marinos, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Puerto Madryn, Chubut, Argentina
| | - Alejo J. Irigoyen
- Centro para el Estudio de Sistemas Marinos, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Puerto Madryn, Chubut, Argentina
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Marco-Tresserras J, López-Iborra GM. Nesting Ecology of European Hedgehogs ( Erinaceus europaeus) in Urban Areas in Southeast Spain: Nest Habitat Use and Characteristics. Animals (Basel) 2023; 13:2453. [PMID: 37570262 PMCID: PMC10417487 DOI: 10.3390/ani13152453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/23/2023] [Accepted: 07/26/2023] [Indexed: 08/13/2023] Open
Abstract
Appropriate nesting sites are needed for the presence of European hedgehogs (Erinaceus europaeus) in an area, along with food availability. However, little attention has been paid to them in the literature. This study aimed at analysing, for the first time, the environmental characteristics of nesting sites chosen by hedgehogs, their spatial distribution and the effect of sex and season on them in two types of urban parks in southeastern Spain. A total of 31 hedgehogs were equipped with GPS devices, and 130 hedgehog nests were located and described. Both sexes had a similar number of nests; however, the spatial distribution of the male nests was larger, and they changed nests more frequently than females. The environment around the nests and hosting structures used also differed between the sexes, with males using a higher variety of nesting structures available and females being more selective. The differences in topography and habitat composition of the two urban parks also affected hedgehog nesting ecology, especially in reference to artificial elements like cat feeders. Further studies of nest locations at a microhabitat level are needed to contribute to a better understanding of a hedgehog's requirements, fostering the design of more effective conservation strategies.
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Lubitz N, Daly R, Filmalter JD, Sheaves M, Cowley PD, Naesje TF, Barnett A. Context drives movement patterns in a mobile marine predator. MOVEMENT ECOLOGY 2023; 11:28. [PMID: 37226200 DOI: 10.1186/s40462-023-00390-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/06/2023] [Indexed: 05/26/2023]
Abstract
Intra-specific variability in movement behaviour occurs in all major taxonomic groups. Despite its common occurrence and ecological consequences, individual variability is often overlooked. As a result, there is a persistent gap in knowledge about drivers of intra-specific variability in movement and its role in fulfilling life history requirements. We apply a context-focused approach to bull sharks (Carcharhinus leucas), a highly mobile marine predator, incorporating intra-specific variability to understand how variable movement patterns arise and how they might be altered under future change scenarios. Spatial analysis of sharks, acoustically tagged both at their distributional limit and the centre of distribution in southern Africa, was combined with spatial analysis of acoustically tagged teleost prey and remote-sensing of environmental variables. The objective was to test the hypothesis that varying resource availability and magnitude of seasonal environmental change in different locations interact to produce variable yet predictable movement behaviours across a species' distribution. Sharks from both locations showed high seasonal overlap with predictable prey aggregations. Patterns were variable in the centre of distribution, where residency, small- and large-scale movements were all recorded. In contrast, all animals from the distributional limit performed 'leap-frog migrations', making long-distance migrations bypassing conspecifics in the centre of distribution. By combining multiple variables related to life history requirements for animals in different environments we identified combinations of key drivers that explain the occurrence of differing movement behaviours across different contexts and delineated the effects of environmental factors and prey dynamics on predator movement. Comparisons with other taxa show striking similarities in patterns of intra-specific variability across terrestrial and marine species, suggesting common drivers.
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Affiliation(s)
- Nicolas Lubitz
- Marine Data Technology Hub, College of Science and Engineering, James Cook University, Townsville City, QLD, Australia.
- Biopixel Oceans Foundation, Cairns, QLD, Australia.
| | - Ryan Daly
- Oceanographic Research Institute, Marine Parade, PO Box 10712, 4056, Durban, South Africa
- South African Institute for Aquatic Biodiversity (SAIAB), Private Bag, 1015, 6140, Makhanda, South Africa
| | - John D Filmalter
- South African Institute for Aquatic Biodiversity (SAIAB), Private Bag, 1015, 6140, Makhanda, South Africa
| | - Marcus Sheaves
- Marine Data Technology Hub, College of Science and Engineering, James Cook University, Townsville City, QLD, Australia
| | - Paul D Cowley
- South African Institute for Aquatic Biodiversity (SAIAB), Private Bag, 1015, 6140, Makhanda, South Africa
| | - Tor F Naesje
- Norwegian Institute for Nature Research, P.O. Box 5685, NO- 7485, Torgarden, Trondheim, Norway
| | - Adam Barnett
- Marine Data Technology Hub, College of Science and Engineering, James Cook University, Townsville City, QLD, Australia
- Biopixel Oceans Foundation, Cairns, QLD, Australia
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When host populations move north, but disease moves south: Counter-intuitive impacts of climate change on disease spread. THEOR ECOL-NETH 2023. [DOI: 10.1007/s12080-022-00551-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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