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Přidalová MS, Hamerlík L, Novikmec M, Slobodníková V, Veselská M, Bitušík P, Svitok M. Diversity and distribution of chironomids in Central European ponds. Ecol Evol 2024; 14:e11354. [PMID: 38711486 PMCID: PMC11070637 DOI: 10.1002/ece3.11354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 04/12/2024] [Indexed: 05/08/2024] Open
Abstract
Ponds are common freshwater habitats in the European landscape that substantially contribute to local and regional biodiversity. Chironomids often dominate invertebrate communities in ponds but are usually disregarded in ecological studies due to relatively complicated taxonomy and identification issues. We present a comprehensive overview of the chironomid diversity in 246 ponds spanning a wide range of conditions extending from the Pannonian Plain to the Carpathians. Altogether, we recorded 225 taxa including 192 species from six subfamilies (Podonominae, Tanypodinae, Diamesinae, Prodiamesinae, Orthocladiinae and Chironominae). However, the chironomid taxa inventory is far from complete and about 16% of the total diversity of pond-dwelling chironomids remains undetected. Chironomid alpha diversity showed a significant unimodal pattern along the elevation gradient with the highest number of taxa per pond expected around 790 m a.s.l. Gamma diversity also peaked in mid-elevations (600-800 m), and the common chironomid taxa partitioned the 2100-m long altitudinal gradient relatively evenly. The heterogeneity of chironomid communities among ponds measured as beta diversity was significantly higher in elevations below 800 m. Temperature and the proportion of surrounding forests significantly influenced alpha diversity of chironomid communities, while urban land cover and pond size had no significant effect. Ponds with a mean annual air temperature of approximately 4.8°C and a low proportion of surrounding forests are expected to harbour the most diverse chironomid communities. Our study showed that chironomids represent a very diverse and often exceptionally rich group of pond-dwelling macroinvertebrates. Given the high diversity and broad range of occupied niches, chironomids should not be overlooked in pond ecology studies. On the contrary, they should be considered a potential model group.
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Affiliation(s)
| | - Ladislav Hamerlík
- Department of Biology and EcologyMatej Bel UniversityBanská BystricaSlovakia
- Institute of ZoologySlovak Academy of SciencesBratislavaSlovakia
| | - Milan Novikmec
- Department of Biology and General EcologyTechnical University in ZvolenZvolenSlovakia
| | | | - Marta Veselská
- Department of Biology and General EcologyTechnical University in ZvolenZvolenSlovakia
| | - Peter Bitušík
- Department of Biology and EcologyMatej Bel UniversityBanská BystricaSlovakia
| | - Marek Svitok
- Department of Biology and General EcologyTechnical University in ZvolenZvolenSlovakia
- Department of Forest Ecology, Faculty of Forestry and Wood SciencesCzech University of Life Sciences PraguePragueCzech Republic
- Plant Science and Biodiversity CenterSlovak Academy of SciencesBratislavaSlovakia
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Wang H, Chen J, Qiu M, Shi Z, Zhang S, Dong G, Ma S, Ai T, Ren G, Chen F. Climate change drove the route shift of the ancient Silk Road in two distinct ways. Sci Bull (Beijing) 2024; 69:1153-1160. [PMID: 38433030 DOI: 10.1016/j.scib.2024.02.025] [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: 11/23/2023] [Revised: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 03/05/2024]
Abstract
Although climate change has convincingly been linked to the evolution of human civilization on different temporal scales, its role in influencing the spatial patterns of ancient civilizations has rarely been investigated. The northward shift of the ancient Silk Road (SR) route from the Tarim Basin (TB) to the Junggar Basin during ∼420-850 CE provides the opportunity to investigate the relationship between climate change and the spatial evolution of human societies. Here, we use a new high-resolution chironomid-based temperature reconstruction from arid China, combined with hydroclimatic and historical datasets, to assess the possible effects of climate fluctuations on the shift of the ancient SR route. We found that a cooling/drying climate in the TB triggered the SR route shift during ∼420-600 CE. However, a warming/wetting climate during ∼600-850 CE did not inhibit this shift, but instead promoted it, because of the favorable climate-induced geopolitical conflicts between the Tubo Kingdom and the Tang Dynasty in the TB. Our findings reveal two distinct ways in which climate change drove the spatial evolution of human civilization, and they demonstrate the flexibility of societal responses to climate change.
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Affiliation(s)
- Haipeng Wang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Jianhui Chen
- MOE Key Laboratory of Western China's Environmental Systems, Lanzhou University, Lanzhou 730000, China.
| | - Menghan Qiu
- MOE Key Laboratory of Western China's Environmental Systems, Lanzhou University, Lanzhou 730000, China
| | - Zhilin Shi
- Institute of Dunhuang Studies, School of History & Culture, Lanzhou University, Lanzhou 730000, China
| | - Shengda Zhang
- School of Geography and Remote Sensing, Guangzhou University, Guangzhou 510000, China
| | - Guanghui Dong
- MOE Key Laboratory of Western China's Environmental Systems, Lanzhou University, Lanzhou 730000, China
| | - Shuai Ma
- MOE Key Laboratory of Western China's Environmental Systems, Lanzhou University, Lanzhou 730000, China
| | - Tao Ai
- Xinjiang Institute of Cultural Relics and Archaeology, Ürümqi 830011, China
| | - Guan Ren
- Archaeology of Northern Ethnicity Institute, Renmin University of China, Beijing 100872, China
| | - Fahu Chen
- ALPHA, State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; MOE Key Laboratory of Western China's Environmental Systems, Lanzhou University, Lanzhou 730000, China
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Cao Y, Peng J, Zhou S, Chen X. Impacts of climate warming and atmospheric deposition on recent shifts in chironomid communities in two alpine lakes, eastern China. ENVIRONMENTAL RESEARCH 2024; 246:118133. [PMID: 38191047 DOI: 10.1016/j.envres.2024.118133] [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: 08/24/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 01/10/2024]
Abstract
Climate warming and atmospheric deposition are altering alpine lake ecosystems at unprecedented rates, whereas their direct and indirect effects on primary consumer communities are unclear. This study presents sedimentary multi-proxy records including chironomids, diatoms, elements and stable isotopes of carbon and nitrogen in 210Pb-dated cores from two alpine lakes located above the timberline in the Taibai Mountain, eastern China. Before ∼2000 CE, chironomid communities were co-dominated by Heterotrissocladius marcidus-type and Micropsectra atrofasciata-type in the two lakes. Thereafter, Tanytarsus glabrescens-type increased rapidly to be a dominant species. Redundancy analyses (RDAs) revealed that chironomid fauna shifts were significantly correlated with rising diatom concentrations in both lakes, declining Ti content in the upstream lake and δ13C depletion in the downstream lake. Although temperature, precipitation and δ15N were not significant explanatory variables in RDAs, climate warming and atmospheric deposition likely promoted terrestrial and aquatic primary production, indicated by synchronous increases in organic matter contents and diatom concentrations in the two sediment cores. Since diatoms contain essential polyunsaturated fatty acids that are essential for chironomids, rising diatom concentrations can promote food quantity and quality. In addition, increased primary production would create organic substrates for chironomid larvae. Recent shifts in chironomid fauna driven by indirect effects of global warming and atmospheric deposition might be a widespread phenomenon in alpine lakes, probably triggering regime shifts in headwater lake ecosystems.
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Affiliation(s)
- Yanmin Cao
- College of Resources and Environment, South-Central Minzu University, Wuhan, 430074, China; School of Geography and Environmental Science, University of Southampton, Southampton, SO17 1BJ, UK; Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan, 430078, China.
| | - Jia Peng
- Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan, 430078, China
| | - Siqi Zhou
- College of Resources and Environment, South-Central Minzu University, Wuhan, 430074, China
| | - Xu Chen
- School of Geography and Environmental Science, University of Southampton, Southampton, SO17 1BJ, UK; Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan, 430078, China
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Åhlén D, Peacock M, Brodin Y, Hambäck PA. Wetland productivity determines trade-off between biodiversity support and greenhouse gas production. Ecol Evol 2023; 13:e10619. [PMID: 37869431 PMCID: PMC10587742 DOI: 10.1002/ece3.10619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 09/13/2023] [Accepted: 10/04/2023] [Indexed: 10/24/2023] Open
Abstract
Establishing wetlands for nutrient capture and biodiversity support may introduce trade-offs between environmentally beneficial functions and detrimental greenhouse gas emissions. Investigating the interaction of nutrient capture, primary production, greenhouse gas production and biodiversity support is imperative to understanding the overall function of wetlands and determining possible beneficial synergistic effects and trade-offs. Here, we present temporally replicated data from 17 wetlands in hemi-boreal Sweden. We explored the relationship between nutrient load, primary producing algae, production of methane and nitrous oxide, and emergence rates of chironomids to determine what factors affected each and how they related to each other. Chironomid emergence rates correlated positively with methane production and negatively with nitrous oxide production, where water temperature was the main driving factor. Increasing nutrient loads reduced methanogenesis through elevated nitrogen concentrations, while simultaneously enhancing nitrous oxide production. Nutrient loads only indirectly increased chironomid emergence rates through increased chlorophyll-a concentration, via increased phosphorus concentrations, with certain taxa and food preference functional groups benefitting from increased chlorophyll-a concentrations. However, water temperature seemed to be the main driving factor for chironomid emergence rates, community composition and diversity, as well as for greenhouse gas production. These findings increase our understanding of the governing relationships between biodiversity support and greenhouse gas production, and should inform future management when constructing wetlands.
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Affiliation(s)
- David Åhlén
- Department of Ecology, Environment and Plant SciencesStockholm UniversityStockholmSweden
| | - Mike Peacock
- Department of Aquatic Sciences and AssessmentSwedish University of Agricultural SciencesUppsalaSweden
- Department of Geography and Planning, School of Environmental SciencesUniversity of LiverpoolLiverpoolUK
| | - Yngve Brodin
- Department of ZoologyThe Swedish Museum of Natural HistoryStockholmSweden
| | - Peter A. Hambäck
- Department of Ecology, Environment and Plant SciencesStockholm UniversityStockholmSweden
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de Melo DB, Dolbeth M, Paiva FF, Molozzi J. Extreme drought scenario shapes different patterns of Chironomid coexistence in reservoirs in a semi-arid region. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 821:153053. [PMID: 35038537 DOI: 10.1016/j.scitotenv.2022.153053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/27/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Semi-arid regions are particularly prone to extreme climate events such as droughts, which result in drastic fluctuations in the water volume of aquatic ecosystems, including artificial ones. As these climate extremes intensify, species must adapt, however, not all species can persist under new climate regimes in such a short period of time. In this study, we evaluated how fluctuations in the water levels of reservoirs, caused by drought, affect Chironomidae diversity patterns in a semi-arid region. We studied six reservoirs (256 sites) in two basins in Northeastern Brazil, exposed to different levels of anthropic impact. Sampling was carried out in 2014, 2015 (both extremely dry years) and 2019. A dead water volume was attained during the extreme drought in 2015, consequently affecting the reservoir and resulting in a low diversity, abundance, and functional redundancy of the Chironomidae assemblages. Despite precipitation increases in 2019, some reservoirs continued to be water deficient. These drastic water fluctuations led to different patterns in Chironomidae taxonomic and functional diversity, which were also influenced by anthropic stressors. Thus, the most impacted basin presented lower diversity, with some species and trait turnover between reservoirs. The opposite trend was observed in the least impacted basin. Overall, taxonomic and functional diversity decreased with decreasing water volume, resulting in a community dominated by small-medium sized individuals with multivoltine cycles and hemoglobin and diapause resistant forms, conferring higher tolerance to water stress. The drought and consequent water volume fluctuations throughout the years seemed to exacerbate the water quality due to pre-existing exposure to anthropic impacts (e.g., domestic discharge, fishing activity, agriculture, livestock). This resulted in biotic homogenization, with an observed loss of taxa and traits. This study reinforced the need to implement habitat conservation and water quality improvement strategies to prevent further ecosystem damage in the face of climate change uncertainty.
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Affiliation(s)
- Dalescka Barbosa de Melo
- Universidade Estadual da Paraíba, Campus I, Departamento de Biologia - Programa de Pós-graduação em Ecologia e Conservação, Av. Baraúnas, 351, Bairro Universitário, CEP: 58429-500, Campina Grande, Brazil.
| | - Marina Dolbeth
- CIIMAR- Interdisciplinary Centre of Marine and Environmental Research, Universidade do Porto, Novo Edifício do Terminal de Cruzeiros do Porto de Leixões, Matosinhos, Portugal.
| | - Franciely Ferreira Paiva
- Universidade Estadual da Paraíba, Campus I, Departamento de Biologia - Programa de Pós-graduação em Ecologia e Conservação, Av. Baraúnas, 351, Bairro Universitário, CEP: 58429-500, Campina Grande, Brazil.
| | - Joseline Molozzi
- Universidade Estadual da Paraíba, Campus I, Departamento de Biologia - Programa de Pós-graduação em Ecologia e Conservação, Av. Baraúnas, 351, Bairro Universitário, CEP: 58429-500, Campina Grande, Brazil.
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Huang J, Miao X, Wang Q, Menzel F, Tang P, Yang D, Wu H, Vogler AP. Metabarcoding reveals massive species diversity of Diptera in a subtropical ecosystem. Ecol Evol 2022; 12:e8535. [PMID: 35127039 PMCID: PMC8796913 DOI: 10.1002/ece3.8535] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 12/08/2021] [Accepted: 12/22/2021] [Indexed: 11/07/2022] Open
Abstract
Diptera is often considered to be the richest insect group due to its great species diversity and broad ecological versatility. However, data on dipteran diversity from subtropical ecosystems have hitherto been scarce, due to the lack of studies conducted at an appropriate large scale. We investigated the diversity and composition of Diptera communities on Tianmu Mountain, Zhejiang, China, using DNA metabarcoding technology, and evaluated their dynamic responses to the effects of slope aspect, season, and altitudinal zone. A total of 5,092 operational taxonomic units (OTUs) were discovered and tentatively assigned to 72 dipteran families, including 2 family records new for China and 30 family records new for the locality. Cecidomyiidae, Sciaridae, and Phoridae were the predominant families, representing 53.6% of total OTUs, while 52 families include >95% unidentified and presumed undescribed species. We found that the community structure of Diptera was significantly affected by aspect, seasonality (month) and elevation, with richer diversity harbored in north-facing than south-facing slopes, and seasonality a more profound driver of community structure and diversity than elevation. Overall, massive species diversity of Diptera communities was discovered in this subtropical ecosystem of east China. The huge diversity of potentially undescribed species only revealed by metabarcoding now requires more detailed taxonomic study, as a step toward an evolutionary integration that accumulates information on species' geographic ranges, ecological traits, functional roles, and species interactions, and thus places the local communities in the context of the growing knowledge base of global biodiversity and its response to environmental change.
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Affiliation(s)
- Junhao Huang
- Department of Forestry ProtectionSchool of Forestry and BiotechnologyZhejiang A&F UniversityHangzhouChina
| | - Xiaoqian Miao
- Department of Forestry ProtectionSchool of Forestry and BiotechnologyZhejiang A&F UniversityHangzhouChina
| | - Qingyun Wang
- Department of Forestry ProtectionSchool of Forestry and BiotechnologyZhejiang A&F UniversityHangzhouChina
| | - Frank Menzel
- Senckenberg Deutsches Entomologisches InstitutMünchebergGermany
| | - Pu Tang
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Agricultural EntomologyInstitute of Insect SciencesZhejiang UniversityHangzhouChina
| | - Ding Yang
- College of Plant ProtectionChina Agricultural UniversityBeijingChina
| | - Hong Wu
- Department of Forestry ProtectionSchool of Forestry and BiotechnologyZhejiang A&F UniversityHangzhouChina
| | - Alfried P. Vogler
- Department of Life SciencesNatural History MuseumLondonUK
- Department of Life SciencesImperial College LondonAscotUK
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Nazarova LB, Frolova LA, Palagushkina OV, Rudaya NA, Syrykh LS, Grekov IM, Solovieva N, Loskutova OA. Recent shift in biological communities: A case study from the Eastern European Russian Arctic (Bol`shezemelskaya Tundra). Polar Biol 2021. [DOI: 10.1007/s00300-021-02876-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Baker NJ, Pilotto F, Jourdan J, Beudert B, Haase P. Recovery from air pollution and subsequent acidification masks the effects of climate change on a freshwater macroinvertebrate community. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 758:143685. [PMID: 33288265 DOI: 10.1016/j.scitotenv.2020.143685] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/30/2020] [Accepted: 11/07/2020] [Indexed: 06/12/2023]
Abstract
Freshwater ecosystems are dynamic, complex systems with a multitude of physical and ecological processes and stressors which drive fluctuations on the community-level. Disentangling the effects of different processes and stressors is challenging due to their interconnected nature. However, as protected areas (i.e. national parks) are less anthropogenically impacted, they are ideal for investigating single stressors. We focus on the Bavarian Forest National Park, a Long-Term Ecological Research (LTER) site in Germany, where the major stressors are climate warming, air pollution (i.e. acidification) and bark beetle infestations. We investigated the effects of these stressors on freshwater macroinvertebrates using comprehensive long-term (1983-2014) datasets comprising high-resolution macroinvertebrate and physico-chemical data from a near-natural stream. Macroinvertebrate communities have undergone substantial changes over the past 32 years, highlighted by increases in overall community abundance (+173%) and richness (+51.6%) as well as taxonomic restructuring driven by a disproportional increase of dipterans. Prior to the year 2000, regression analyses revealed a decline in sulphate deposition and subsequent recovery from historical acidification as potential drivers of the increases in abundance and richness rather than to increases in water temperature (1.5 °C overall increase). Post 2000, however, alterations to nutrient cycling caused by bark beetle infestations coupled with warming temperatures were correlated to taxonomic restructuring and disproportional increases of dipterans at the expense of sensitive taxa such as plecopterans and trichopterans. Our results highlight the challenges when investigating the effects of climate change within a multi-stressor context. Even in conservation areas, recovery from previous disturbance might mask the effects of ongoing disturbances like climate change. Overall, we observed strong community restructuring, demonstrating that stenothermal headwater communities face additional stress due to emerging competition with tolerant taxa. Conservation efforts should consider the temporal variability of communities and their recovery from disturbances to adequately identify species vulnerable to local or widespread extinction.
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Affiliation(s)
- Nathan Jay Baker
- Department of River Ecology and Conservation, Senckenberg Research Institute and Natural History Museum Frankfurt, Gelnhausen, Germany.
| | - Francesca Pilotto
- Environmental Archaeology Lab, Department of Historical, Philosophical and Religious Studies, Umeå University, Umeå, Sweden
| | - Jonas Jourdan
- Department of Aquatic Ecotoxicology, Johann Wolfgang Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Burkhard Beudert
- Department of Conservation and Research, Bavarian Forest National Park, Grafenau, Germany
| | - Peter Haase
- Department of River Ecology and Conservation, Senckenberg Research Institute and Natural History Museum Frankfurt, Gelnhausen, Germany; Faculty of Biology, University of Duisburg-Essen, Essen, Germany
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Allan ER, Bollmann S, Peremyslova E, Blouin M. Neither heat pulse, nor multigenerational exposure to a modest increase in water temperature, alters the susceptibility of Guadeloupean Biomphalaria glabrata to Schistosoma mansoni infection. PeerJ 2020; 8:e9059. [PMID: 32351792 PMCID: PMC7183749 DOI: 10.7717/peerj.9059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/04/2020] [Indexed: 12/22/2022] Open
Abstract
There are increasing concerns regarding the role global climate change will have on many vector-borne diseases. Both mathematical models and laboratory experiments suggest that schistosomiasis risk may change as a result of the effects of increasing temperatures on the planorbid snails that host schistosomes. Heat pulse/heat shock of the BS90 strain of Biomphalaria glabrata was shown to increase the rate of infection by Schistosoma mansoni, but the result was not replicable in a follow up experiment by a different lab. We characterised the susceptibility and cercarial shedding of Guadeloupean B. glabrata after infection with S. mansoni under two temperature regimes: multigenerational exposure to small increases in temperature, and extreme heat pulse events. Neither long-term, multigenerational rearing at elevated temperatures, nor transient heat pulse modified the susceptibility of Guadeloupean B. glabrata to infection (prevalence) or shedding of schistosome cercaria (intensity of infection). These findings suggest that heat pulse-induced susceptibility in snail hosts may be dependent on the strain of the snail and/or schistosome, or on some as-yet unidentified environmental co-factor.
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Affiliation(s)
- Euan R.O. Allan
- School of Veterinary Medicine, Pathobiology, St. George’s University, St. George’s, Grenada
| | - Stephanie Bollmann
- Integrative Biology, Oregon State University, Corvallis, OR, United States of America
| | - Ekaterina Peremyslova
- Integrative Biology, Oregon State University, Corvallis, OR, United States of America
| | - Michael Blouin
- Integrative Biology, Oregon State University, Corvallis, OR, United States of America
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Saulnier-Talbot É, Antoniades D, Pienitz R. Hotspots of biotic compositional change in lakes along vast latitudinal transects in northern Canada. GLOBAL CHANGE BIOLOGY 2020; 26:2270-2279. [PMID: 31995661 DOI: 10.1111/gcb.15016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/11/2019] [Accepted: 01/17/2020] [Indexed: 06/10/2023]
Abstract
Ecotones mark zones of rapid change in ecological structure at various spatial scales. They are believed to be particularly susceptible to shifts caused by environmental transformation, making them key regions for studying the effects of global change. Here, we explored the variation in assemblage structure of aquatic primary producer and consumer communities across latitudinal transects in northeastern North America (Québec-Labrador) to identify spatial patterns in biodiversity that indicated the location of transition zones across the landscape. We analyzed species richness and the cumulative rate of compositional change (expressed as beta-diversity) of diatoms and chironomids to detect any abrupt shifts in the rate of spatial taxonomic turnover. We used principal coordinates analysis to estimate community turnover with latitude, then applied piecewise linear regression to assess the position of ecotones. Statistically significant changes in assemblage composition occurred at 52 and 55°N, corresponding to the transition between closed- and open-crown forest, and to the southern onset of the forest tundra (i.e., the forest limit), respectively. The spatial distribution of ecotones was most strongly related to air temperature for chironomids and to vegetation- and soil-related chemical attributes of lake water for diatoms, including dissolved organic carbon content and water color. Lakes at mid- to high-latitudes currently face pressures from rapidly rising temperatures, accompanied by large increases in organic carbon inputs from their catchments, often leading to browning and its associated effects. The biota at the base of food webs in lakes located in transition zones are disproportionately affected by the cascading effects of these multi-factorial changes, concurrent with pronounced terrestrial greening observed in these regions. Similar patterns of biotic shifts have been observed along alpine aquatic transects, indicating the potential for widespread restructuring of cold, high-altitude and high-latitude freshwater communities due to global change.
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Affiliation(s)
- Émilie Saulnier-Talbot
- Laboratoire de paléoécologie aquatique (LPA), Département de géographie and Centre d'études nordiques (CEN: Centre for Northern Studies), Université Laval, Québec, QC, Canada
| | - Dermot Antoniades
- Laboratoire de paléoécologie aquatique (LPA), Département de géographie and Centre d'études nordiques (CEN: Centre for Northern Studies), Université Laval, Québec, QC, Canada
| | - Reinhard Pienitz
- Laboratoire de paléoécologie aquatique (LPA), Département de géographie and Centre d'études nordiques (CEN: Centre for Northern Studies), Université Laval, Québec, QC, Canada
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