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Freeman MT, Coulson B, Short JC, Ngcamphalala CA, Makola MO, McKechnie AE. Evolution of avian heat tolerance: The role of atmospheric humidity. Ecology 2024; 105:e4279. [PMID: 38501232 DOI: 10.1002/ecy.4279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 11/12/2023] [Accepted: 01/19/2024] [Indexed: 03/20/2024]
Abstract
The role of atmospheric humidity in the evolution of endotherms' thermoregulatory performance remains largely unexplored, despite the fact that elevated humidity is known to impede evaporative cooling capacity. Using a phylogenetically informed comparative framework, we tested the hypothesis that pronounced hyperthermia tolerance among birds occupying humid lowlands evolved to reduce the impact of humidity-impeded scope for evaporative heat dissipation by comparing heat tolerance limits (HTLs; maximum tolerable air temperature), maximum body temperatures (Tbmax), and associated thermoregulatory variables in humid (19.2 g H2O m-3) versus dry (1.1 g H2O m-3) air among 30 species from three climatically distinct sites (arid, mesic montane, and humid lowland). Humidity-associated decreases in evaporative water loss and resting metabolic rate were 27%-38% and 21%-27%, respectively, and did not differ significantly between sites. Decreases in HTLs were significantly larger among arid-zone (mean ± SD = 3.13 ± 1.12°C) and montane species (2.44 ± 1.0°C) compared to lowland species (1.23 ± 1.34°C), with more pronounced hyperthermia among lowland (Tbmax = 46.26 ± 0.48°C) and montane birds (Tbmax = 46.19 ± 0.92°C) compared to arid-zone species (45.23 ± 0.24°C). Our findings reveal a functional link between facultative hyperthermia and humidity-related constraints on evaporative cooling, providing novel insights into how hygric and thermal environments interact to constrain avian performance during hot weather. Moreover, the macrophysiological patterns we report provide further support for the concept of a continuum from thermal specialization to thermal generalization among endotherms, with adaptive variation in body temperature correlated with prevailing climatic conditions.
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Affiliation(s)
- Marc T Freeman
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria, South Africa
- DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Bianca Coulson
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria, South Africa
- DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - James C Short
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria, South Africa
- DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Celiwe A Ngcamphalala
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Mathome O Makola
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria, South Africa
- DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Andrew E McKechnie
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria, South Africa
- DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
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2
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Ratz T, Chechi TS, Dimopoulou AI, Sedlmair SD, Tuni C. Heatwaves inflict reproductive but not survival costs to male insects. J Exp Biol 2024; 227:jeb246698. [PMID: 38436413 DOI: 10.1242/jeb.246698] [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: 08/31/2023] [Accepted: 02/27/2024] [Indexed: 03/05/2024]
Abstract
Climate change is having a dramatic effect on the environment, with rising global temperatures and more frequent extreme climatic events, such as heatwaves, that can hamper organisms' biological functions. Although it is clear that sudden and extreme temperatures can damage reproductive processes, there is limited understanding of the effects of heatwaves on male mating behaviour and reproductive success. We tested for the effects of heat stress induced by ecologically relevant heatwaves (33°C and 39°C for five consecutive days) on the mating behaviour, reproductive success, body mass and survival of male field crickets Gryllus bimaculatus, paired with untreated females. We predicted life-history and reproductive costs would increase with increasing heatwave intensity. Consistent with our expectations, males exposed to the highest heatwave temperature produced the fewest offspring, while having to increase courtship effort to successfully mate. Males also gained relatively more weight following heatwave exposure. Given that we found no difference in lifetime survival, our results suggest a potential trade-off in resource allocation between somatic maintenance and reproductive investment. Taken together, our findings indicate that sublethal effects of heatwaves could reduce the growth and persistence of animal populations by negatively impacting reproductive rates. These findings highlight the need for considering thermal ecologies, life history and behaviour to better understand the consequences of extreme climatic events on individuals and populations.
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Affiliation(s)
- Tom Ratz
- Department of Biology, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstraße 190, 8057 Zürich, Switzerland
| | - Tejinder Singh Chechi
- Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
| | - Aliki-Ioanna Dimopoulou
- Department of Biology, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
| | - Stephanie Daniela Sedlmair
- Department of Biology, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
| | - Cristina Tuni
- Department of Biology, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy
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3
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Bahlai CA. Forecasting insect dynamics in a changing world. CURRENT OPINION IN INSECT SCIENCE 2023; 60:101133. [PMID: 37858790 DOI: 10.1016/j.cois.2023.101133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 10/04/2023] [Accepted: 10/13/2023] [Indexed: 10/21/2023]
Abstract
Predicting how insects will respond to stressors through time is difficult because of the diversity of insects, environments, and approaches used to monitor and model. Forecasting models take correlative/statistical, mechanistic models, and integrated forms; in some cases, temporal processes can be inferred from spatial models. Because of heterogeneity associated with broad community measurements, models are often unable to identify mechanistic explanations. Many present efforts to forecast insect dynamics are restricted to single-species models, which can offer precise predictions but limited generalizability. Trait-based approaches may offer a good compromise that limits the masking of the ranges of responses while still offering insight. Regardless of the modeling approach, the data used to parameterize a forecasting model should be carefully evaluated for temporal autocorrelation, minimum data needs, and sampling biases in the data. Forecasting models can be tested using near-term predictions and revised to improve future forecasts.
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Affiliation(s)
- Christie A Bahlai
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA; Environmental Science and Design Research Institute, Kent State University, Kent, OH 44242, USA.
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4
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Legge S, Rumpff L, Garnett ST, Woinarski JCZ. Loss of terrestrial biodiversity in Australia: Magnitude, causation, and response. Science 2023; 381:622-631. [PMID: 37561866 DOI: 10.1126/science.adg7870] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/08/2023] [Indexed: 08/12/2023]
Abstract
Australia's biota is species rich, with high rates of endemism. This natural legacy has rapidly diminished since European colonization. The impacts of invasive species, habitat loss, altered fire regimes, and changed water flows are now compounded by climate change, particularly through extreme drought, heat, wildfire, and flooding. Extinction rates, already far exceeding the global average for mammals, are predicted to escalate across all taxa, and ecosystems are collapsing. These losses are symptomatic of shortcomings in resourcing, law, policy, and management. Informed by examples of advances in conservation practice from invasive species control, Indigenous land management, and citizen science, we describe interventions needed to enhance future resilience. Many characteristics of Australian biodiversity loss are globally relevant, with recovery requiring society to reframe its relationship with the environment.
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Affiliation(s)
- Sarah Legge
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
- Fenner School of Society and the Environment, The Australian National University, Acton, Canberra, Australian Capital Territory, Australia
| | - Libby Rumpff
- School of Agriculture, Food and Ecosystem Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Stephen T Garnett
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
| | - John C Z Woinarski
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
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5
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Pigot AL, Merow C, Wilson A, Trisos CH. Abrupt expansion of climate change risks for species globally. Nat Ecol Evol 2023; 7:1060-1071. [PMID: 37202503 DOI: 10.1038/s41559-023-02070-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 04/14/2023] [Indexed: 05/20/2023]
Abstract
Climate change is already exposing species to dangerous temperatures driving widespread population and geographical contractions. However, little is known about how these risks of thermal exposure will expand across species' existing geographical ranges over time as climate change continues. Here, using geographical data for approximately 36,000 marine and terrestrial species and climate projections to 2100, we show that the area of each species' geographical range at risk of thermal exposure will expand abruptly. On average, more than 50% of the increase in exposure projected for a species will occur in a single decade. This abruptness is partly due to the rapid pace of future projected warming but also because the greater area available at the warm end of thermal gradients constrains species to disproportionately occupy sites close to their upper thermal limit. These geographical constraints on the structure of species ranges operate both on land and in the ocean and mean that, even in the absence of amplifying ecological feedbacks, thermally sensitive species may be inherently vulnerable to sudden warming-driven collapse. With higher levels of warming, the number of species passing these thermal thresholds, and at risk of abrupt and widespread thermal exposure, increases, doubling from less than 15% to more than 30% between 1.5 °C and 2.5 °C of global warming. These results indicate that climate threats to thousands of species are expected to expand abruptly in the coming decades, thereby highlighting the urgency of mitigation and adaptation actions.
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Affiliation(s)
- Alex L Pigot
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London, UK.
| | - Cory Merow
- Eversource Energy Center and Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Adam Wilson
- Department of Geography, University at Buffalo, Buffalo, NY, USA
| | - Christopher H Trisos
- African Climate and Development Initiative, University of Cape Town, Cape Town, South Africa
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6
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Boult VL. Forecast-based action for conservation. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2023; 37:e14054. [PMID: 36661067 DOI: 10.1111/cobi.14054] [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: 07/21/2022] [Revised: 11/23/2022] [Accepted: 12/21/2022] [Indexed: 05/30/2023]
Abstract
Extreme weather events pose an immediate threat to biodiversity, but existing conservation strategies have limitations. Advances in meteorological forecasting and innovation in the humanitarian sector provide a possible solution-forecast-based action (FbA). The growth of ecological forecasting demonstrates the huge potential to anticipate conservation outcomes, but a lack of operational examples suggests a new approach is needed to translate forecasts into action. FbA provides such a framework, formalizing the use of meteorological forecasts to anticipate and mitigate the impacts of extreme weather. Based on experience from the humanitarian sector, I suggest how FbA could work in conservation, demonstrating key concepts using the theoretical example of heatwave impacts on sea turtle embryo mortality, and address likely challenges in realizing FbA for conservation, including establishing a financing mechanism, allocating funds to actions, and decision-making under uncertainty. FbA will demand changes in conservation research, practice, and governance. Researchers must increase efforts to understand the impacts of extreme weather at more immediate and actionable timescales and should coproduce forecasts of such impacts with practitioners. International conservation funders should establish systems to fund anticipatory actions based on uncertain forecasts.
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Affiliation(s)
- Victoria L Boult
- Department of Meteorology, University of Reading, Reading, UK
- National Centre for Atmospheric Science, Reading, UK
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7
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Tulloch AIT, Jackson MV, Bayraktarov E, Carey AR, Correa-Gomez DF, Driessen M, Gynther IC, Hardie M, Moseby K, Joseph L, Preece H, Suarez-Castro AF, Stuart S, Woinarski JCZ, Possingham HP. Effects of different management strategies on long-term trends of Australian threatened and near-threatened mammals. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2023; 37:e14032. [PMID: 36349543 DOI: 10.1111/cobi.14032] [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: 01/05/2022] [Revised: 08/16/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Monitoring is critical to assess management effectiveness, but broadscale systematic assessments of monitoring to evaluate and improve recovery efforts are lacking. We compiled 1808 time series from 71 threatened and near-threatened terrestrial and volant mammal species and subspecies in Australia (48% of all threatened mammal taxa) to compare relative trends of populations subject to different management strategies. We adapted the Living Planet Index to develop the Threatened Species Index for Australian Mammals and track aggregate trends for all sampled threatened mammal populations and for small (<35 g), medium (35-5500 g), and large mammals (>5500 g) from 2000 to 2017. Unmanaged populations (42 taxa) declined by 63% on average; unmanaged small mammals exhibited the greatest declines (96%). Populations of 17 taxa in havens (islands and fenced areas that excluded or eliminated introduced red foxes [Vulpes vulpes] and domestic cats [Felis catus]) increased by 680%. Outside havens, populations undergoing sustained predator baiting initially declined by 75% but subsequently increased to 47% of their abundance in 2000. At sites where predators were not excluded or baited but other actions (e.g., fire management, introduced herbivore control) occurred, populations of small and medium mammals declined faster, but large mammals declined more slowly, than unmanaged populations. Only 13% of taxa had data for both unmanaged and managed populations; index comparisons for this subset showed that taxa with populations increasing inside havens declined outside havens but taxa with populations subject to predator baiting outside havens declined more slowly than populations with no management and then increased, whereas unmanaged populations continued to decline. More comprehensive and improved monitoring (particularly encompassing poorly represented management actions and taxonomic groups like bats and small mammals) is required to understand whether and where management has worked. Improved implementation of management for threats other than predation is critical to recover Australia's threatened mammals.
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Affiliation(s)
- Ayesha I T Tulloch
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Queensland, Australia
| | - Micha V Jackson
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Queensland, Australia
| | - Elisa Bayraktarov
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Queensland, Australia
- Research, Specialised and Data Foundations, Digital Solutions, Griffith University, Nathan, Queensland, Australia
| | - Alexander R Carey
- Saving our Species Program, Department of the Environment, Sydney, New South Wales, Australia
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
| | - Diego F Correa-Gomez
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Queensland, Australia
| | - Michael Driessen
- Conservation Science Section, Natural Resources and Environment Tasmania, Hobart, Tasmania, Australia
| | - Ian C Gynther
- Department of Environment and Science, Moggill, Queensland, Australia
- Biodiversity and Geosciences Program, Queensland Museum, South Brisbane, Queensland, Australia
| | - Mel Hardie
- Department of Environment, Land, Water and Planning, Melbourne, Victoria, Australia
| | - Katherine Moseby
- Arid Recovery, Roxby Downs, South Australia, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Liana Joseph
- Australian Wildlife Conservancy, Subiaco East, Western Australia, Australia
| | - Harriet Preece
- Department of Environment and Science, Dutton Park, Queensland, Australia
| | - Andrés Felipe Suarez-Castro
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Queensland, Australia
- Australian Rivers Institute, Griffith University, Nathan, Queensland, Australia
| | - Stephanie Stuart
- Saving our Species Program, Department of the Environment, Sydney, New South Wales, Australia
| | - John C Z Woinarski
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
| | - Hugh P Possingham
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Queensland, Australia
- The Nature Conservancy, Arlington, Virginia, USA
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8
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Hector TE, Gehman ALM, King KC. Infection burdens and virulence under heat stress: ecological and evolutionary considerations. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220018. [PMID: 36744570 PMCID: PMC9900716 DOI: 10.1098/rstb.2022.0018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
As a result of global change, hosts and parasites (including pathogens) are experiencing shifts in their thermal environment. Despite the importance of heat stress tolerance for host population persistence, infection by parasites can impair a host's ability to cope with heat. Host-parasite eco-evolutionary dynamics will be affected if infection reduces host performance during heating. Theory predicts that within-host parasite burden (replication rate or number of infecting parasites per host), a key component of parasite fitness, should correlate positively with virulence-the harm caused to hosts during infection. Surprisingly, however, the relationship between within-host parasite burden and virulence during heating is often weak. Here, we describe the current evidence for the link between within-host parasite burden and host heat stress tolerance. We consider the biology of host-parasite systems that may explain the weak or absent link between these two important host and parasite traits during hot conditions. The processes that mediate the relationship between parasite burden and host fitness will be fundamental in ecological and evolutionary responses of host and parasites in a warming world. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
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Affiliation(s)
- T. E. Hector
- Department of Biology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
| | - A.-L. M. Gehman
- Hakai Institute, End of Kwakshua Channel, Calvert Island, BC Canada, V0N 1M0,Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC Canada, V6T 1Z4
| | - K. C. King
- Department of Biology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
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Bruno L, Nappo MA, Ferrari L, Di Lecce R, Guarnieri C, Cantoni AM, Corradi A. Nipah Virus Disease: Epidemiological, Clinical, Diagnostic and Legislative Aspects of This Unpredictable Emerging Zoonosis. Animals (Basel) 2022; 13:ani13010159. [PMID: 36611767 PMCID: PMC9817766 DOI: 10.3390/ani13010159] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023] Open
Abstract
Nipah virus (NiV) infection is a viral disease caused by a Henipavirus, belonging to the Paramyxoviridae family, responsible for a zoonosis. The course of the disease can be very serious and lead to death. NiV natural hosts are fruit bats (also known as megabats) belonging to the Pteropodidae family, especially those of the Pteropus genus. Natural infection in domestic animals has been described in farming pigs, horses, domestic and feral dogs and cats. Natural NiV transmission is possible intra-species (pig-to-pig, human-to-human) and inter-species (flying bat-to-human, pig-to-human, horse-to-human). The infection can be spread by humans or animals in different ways. It is peculiar how the viral transmission modes among different hosts also change depending on the geographical area for different reasons, including different breeding methods, eating habits and the recently identified genetic traits/molecular features of main virus proteins related to virulence. Outbreaks have been described in Malaysia, Singapore, Bangladesh, India and the Philippines with, in some cases, severe respiratory and neurological disease and high mortality in both humans and pigs. Diagnosis can be made using different methods including serological, molecular, virological and immunohistochemical methods. The cornerstones for control of the disease are biosecurity (via the correct management of reservoir and intermediate/amplifying hosts) and potential vaccines which are still under development. However, the evaluation of the potential influence of climate and anthropogenic changes on the NiV reservoir bats and their habitat as well as on disease spread and inter-specific infections is of great importance. Bats, as natural reservoirs of the virus, are responsible for the viral spread and, therefore, for the outbreaks of the disease in humans and animals. Due to the worldwide distribution of bats, potential new reports and spillovers are not to be dismissed in the future.
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Affiliation(s)
- Luigi Bruno
- Department of Prevention, Azienda Sanitaria Locale (A.S.L.) Napoli 3 Sud, 80053 Castellammare di Stabia, Italy
- Correspondence: (L.B.); (L.F.)
| | - Maria Anna Nappo
- Department of Prevention, Azienda Sanitaria Locale (A.S.L.) Napoli 3 Sud, 80053 Castellammare di Stabia, Italy
| | - Luca Ferrari
- Department of Veterinary Science, University of Parma, 43126 Parma, Italy
- Correspondence: (L.B.); (L.F.)
| | - Rosanna Di Lecce
- Department of Veterinary Science, University of Parma, 43126 Parma, Italy
| | - Chiara Guarnieri
- Department of Veterinary Science, University of Parma, 43126 Parma, Italy
| | - Anna Maria Cantoni
- Department of Veterinary Science, University of Parma, 43126 Parma, Italy
| | - Attilio Corradi
- Department of Veterinary Science, University of Parma, 43126 Parma, Italy
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10
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Predicted impacts of climate change and extreme temperature events on the future distribution of fruit bat species in Australia. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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11
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Czenze ZJ, Noakes MJ, Wojciechowski MS. Home is where the heat is: Thermoregulation of European bats inhabiting artificial roosts and the threat of heat waves. J Appl Ecol 2022. [DOI: 10.1111/1365-2664.14230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Zenon J. Czenze
- Centre for Behavioural and Physiological Ecology University of New England Armidale NSW Australia
| | - Matthew J. Noakes
- Department of Vertebrate Zoology and Ecology Nicolaus Copernicus University Toruń Poland
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12
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The Impacts of Drought on the Health and Demography of Eastern Grey Kangaroos. Animals (Basel) 2022; 12:ani12030256. [PMID: 35158580 PMCID: PMC8833700 DOI: 10.3390/ani12030256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/12/2022] [Accepted: 01/20/2022] [Indexed: 02/01/2023] Open
Abstract
Simple Summary Eastern grey kangaroos, like most wildlife, are facing an increasingly uncertain future under rapid climate change. How individuals and populations cope with extreme climatic events will influence their capacity to adapt and persist. Here, we analyzed how drought impacted eastern grey kangaroo populations by focusing on their body condition, demography, activity rates at water points, and the likelihood of parasitic infections. We found that body condition was lower as environmental conditions became more extreme and that fewer males in the population were observed. The proportion of juveniles within the population increased as more favorable conditions returned. Kangaroos with poor body conditions were more likely to become hosts to ticks, while higher parasite egg burdens in scats occurred in autumn. Our study has shown that the impacts eastern grey kangaroos face during climatic events such as drought can be severe and may have long-term consequences. Abstract Extreme climatic events such as droughts and floods are expected to become more intense and severe under climate change, especially in the southern and eastern parts of Australia. We aimed to quantify the relationship between body condition scores (BCS), demography, activity rate, and parasitic infections of eastern grey kangaroos on a large conservation property under different climate extremes by employing camera traps established at artificial water points (AWPs). The survey period included a severe drought, broken by a significant flooding event. Climatic and environmental conditions were documented using remotely sensed indices of moisture availability and vegetation productivity. These conditions were found to affect all health and population parameters measured. BCS, juvenile proportions, and sex ratios were most correlated with 6-month lags in climatic conditions, while the activity rate of kangaroos at AWPs was most correlated with vegetation productivity. Ticks were mostly found on individuals with a poorer BCS, while the concentration of parasitic eggs in feces was higher in autumn than in spring. Our study offers a glimpse into some of the environmental drivers of eastern grey kangaroo populations and their health, information that may become increasingly important in today’s climate. It further emphasizes the importance of this knowledge for wildlife conservation efforts appropriate to managing the impact of climate change alongside other threats.
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13
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Czenze ZJ, Freeman MT, Kemp R, van Jaarsveld B, Wolf BO, McKechnie AE. Efficient Evaporative Cooling and Pronounced Heat Tolerance in an Eagle-Owl, a Thick-Knee and a Sandgrouse. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.799302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Avian evaporative cooling and the maintenance of body temperature (Tb) below lethal limits during heat exposure has received more attention in small species compared to larger-bodied taxa. Here, we examined thermoregulation at air temperatures (Tair) approaching and exceeding normothermic Tb in three larger birds that use gular flutter, thought to provide the basis for pronounced evaporative cooling capacity and heat tolerance. We quantified Tb, evaporative water loss (EWL) and resting metabolic rate (RMR) in the ∼170-g Namaqua sandgrouse (Pterocles namaqua), ∼430-g spotted thick-knee (Burhinus capensis) and ∼670-g spotted eagle-owl (Bubo africanus), using flow-through respirometry and a stepped Tair profile with very low chamber humidities. All three species tolerated Tair of 56–60°C before the onset of severe hyperthermia, with maximum Tb of 43.2°C, 44.3°C, and 44.2°C in sandgrouse, thick-knees and eagle-owls, respectively. Evaporative scope (i.e., maximum EWL/minimum thermoneutral EWL) was 7.4 in sandgrouse, 12.9 in thick-knees and 7.8 in eagle-owls. The relationship between RMR and Tair varied substantially among species: whereas thick-knees and eagle-owls showed clear upper critical limits of thermoneutrality above which RMR increased rapidly and linearly, sandgrouse did not. Maximum evaporative heat loss/metabolic heat production ranged from 2.8 (eagle-owls) to 5.5 (sandgrouse), the latter the highest avian value yet reported. Our data reveal some larger species with gular flutter possess pronounced evaporative cooling capacity and heat tolerance and, when taken together with published data, show thermoregulatory performance varies widely among species larger than 250 g. Our data for Namaqua sandgrouse reveal unexpectedly pronounced variation in the metabolic costs of evaporative cooling within the genus Pterocles.
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14
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D'Amelio PB, Ferreira AC, Fortuna R, Paquet M, Silva LR, Theron F, Doutrelant C, Covas R. Disentangling climatic and nest predator impact on reproductive output reveals adverse high-temperature effects regardless of helper number in an arid-region cooperative bird. Ecol Lett 2021; 25:151-162. [PMID: 34787354 PMCID: PMC9299450 DOI: 10.1111/ele.13913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/04/2021] [Accepted: 09/29/2021] [Indexed: 01/20/2023]
Abstract
Climate exerts a major influence on reproductive processes, and an understanding of the mechanisms involved and which factors might mitigate adverse weather is fundamental under the ongoing climate change. Here, we study how weather and nest predation influence reproductive output in a social species, and examine whether larger group sizes can mitigate the adverse effects of these factors. We used a 7‐year nest predator‐exclusion experiment on an arid‐region cooperatively breeding bird, the sociable weaver. We found that dry and, especially, hot weather were major drivers of nestling mortality through their influence on nest predation. However, when we experimentally excluded nest predators, these conditions were still strongly associated with nestling mortality. Group size was unimportant against nest predation and, although positively associated with reproductive success, it did not mitigate the effects of adverse weather. Hence, cooperative breeding might have a limited capacity to mitigate extreme weather effects.
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Affiliation(s)
- Pietro B D'Amelio
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa.,Centre d'Ecologie Fonctionnelle et Evolutive, CEFE, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, 34293, France
| | - André C Ferreira
- Centre d'Ecologie Fonctionnelle et Evolutive, CEFE, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, 34293, France.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, 4485-661, Portugal.,CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, 4485-661, Portugal
| | - Rita Fortuna
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, 4485-661, Portugal.,CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, 4485-661, Portugal.,Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4099-002, Porto, Portugal
| | - Matthieu Paquet
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, SE-75007, Sweden
| | - Liliana R Silva
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, 4485-661, Portugal.,CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, 4485-661, Portugal
| | - Franck Theron
- Centre d'Ecologie Fonctionnelle et Evolutive, CEFE, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, 34293, France.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, 4485-661, Portugal.,CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, 4485-661, Portugal
| | - Claire Doutrelant
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa.,Centre d'Ecologie Fonctionnelle et Evolutive, CEFE, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, 34293, France
| | - Rita Covas
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, 4485-661, Portugal.,CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, 4485-661, Portugal
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15
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Honey R, McLean C, Murray BR, Webb JK. Insulated nest boxes provide thermal refuges for wildlife in urban bushland during summer heatwaves. JOURNAL OF URBAN ECOLOGY 2021. [DOI: 10.1093/jue/juab032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
In urban bushland, the installation of nest boxes is widely used to compensate for the loss of natural tree hollows. However, current nest box designs may not provide thermal refuges for wildlife during summer heatwaves, particularly if internal temperatures exceed the upper critical temperatures of wildlife. We investigated whether the addition of roofing insulation to nest boxes deployed for sugar gliders (Petaurus breviceps) and squirrel gliders (Petaurus norfolcensis) in urban bushland would reduce internal nest box temperatures during summer heatwaves. We measured temperatures of 44 insulated and 47 uninsulated nest boxes during one of the hottest summers on record (2018–2019) in the Lake Macquarie region of NSW, Australia, a period during which several prolonged heatwaves occurred. Over the 90-day study, maximum temperatures were, on average, 3.1°C lower in insulated boxes than in uninsulated boxes. The addition of insulation significantly lowered nest box temperatures regardless of aspect (north or south facing) or day of measurement. Temperatures exceeded the upper critical temperature (35.1°C) of gliders more frequently in uninsulated nest boxes (28% of days) than in insulated nest boxes (8% days). Although the addition of insulation to nest boxes lowered their internal temperatures, during heatwaves spanning 23 days, nest box temperatures exceeded the upper critical temperatures of gliders on 58% and 23% of days in uninsulated and insulated nest boxes respectively. These findings underscore the importance of retaining natural hollows in urban bushland to provide thermally suitable refuges for wildlife during extreme heat events.
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Affiliation(s)
- Reannan Honey
- School of Life Sciences, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Chris McLean
- School of Life Sciences, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Brad R Murray
- School of Life Sciences, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Jonathan K Webb
- School of Life Sciences, University of Technology Sydney, Broadway, NSW 2007, Australia
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16
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Czenze ZJ, Smit B, Jaarsveld B, Freeman MT, McKechnie AE. Caves, crevices and cooling capacity: Roost microclimate predicts heat tolerance in bats. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13918] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Zenon J. Czenze
- South African Research Chair in Conservation Physiology South African National Biodiversity Institute Pretoria South Africa
- Mammal Research Institute, Department of Zoology and Entomology University of Pretoria Pretoria South Africa
| | - Ben Smit
- Department of Zoology and Entomology Rhodes University Makhanda South Africa
| | - Barry Jaarsveld
- South African Research Chair in Conservation Physiology South African National Biodiversity Institute Pretoria South Africa
- Mammal Research Institute, Department of Zoology and Entomology University of Pretoria Pretoria South Africa
| | - Marc T. Freeman
- South African Research Chair in Conservation Physiology South African National Biodiversity Institute Pretoria South Africa
- Mammal Research Institute, Department of Zoology and Entomology University of Pretoria Pretoria South Africa
| | - Andrew E. McKechnie
- South African Research Chair in Conservation Physiology South African National Biodiversity Institute Pretoria South Africa
- Mammal Research Institute, Department of Zoology and Entomology University of Pretoria Pretoria South Africa
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17
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Bourne AR, Ridley AR, Spottiswoode CN, Cunningham SJ. Direct and indirect effects of high temperatures on fledging in a cooperatively breeding bird. Behav Ecol 2021. [DOI: 10.1093/beheco/arab087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Abstract
High temperatures and low rainfall consistently constrain reproduction in arid-zone bird species. Understanding the mechanisms underlying this pattern is critical for predicting how climate change will influence population persistence and to inform conservation and management. In this study, we analyzed Southern Pied Babbler Turdoides bicolor nestling survival, daily growth rate and adult investment behavior during the nestling period over three austral summer breeding seasons. High temperatures were associated with lower body mass, shorter tarsi, and reduced daily growth rates of nestlings. Our piecewise structural equation models suggested that direct impacts of temperature had the strongest influence on nestling size and daily growth rates for both 5-day-old and 11-day-old nestlings, followed by temperature-related adjustments to provisioning rates by adults. Rainfall and group size influenced the behavior of provisioning adults but did not influence nestling growth or survival. Adjustments to adult provisioning strategies did not compensate for direct negative effects of high air temperatures on nestling size or daily growth rates. Detailed mechanistic data like these allow us to model the pathways by which high temperature causes nest failure. In turn, this could allow us to design targeted conservation action to effectively mitigate climate effects.
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Affiliation(s)
- Amanda R Bourne
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
| | - Amanda R Ridley
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Hackett Drive, Crawley, Perth WA, Australia
| | - Claire N Spottiswoode
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Susan J Cunningham
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
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18
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Genomic Approaches for Conservation Management in Australia under Climate Change. Life (Basel) 2021; 11:life11070653. [PMID: 34357024 PMCID: PMC8304512 DOI: 10.3390/life11070653] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 12/28/2022] Open
Abstract
Conservation genetics has informed threatened species management for several decades. With the advent of advanced DNA sequencing technologies in recent years, it is now possible to monitor and manage threatened populations with even greater precision. Climate change presents a number of threats and challenges, but new genomics data and analytical approaches provide opportunities to identify critical evolutionary processes of relevance to genetic management under climate change. Here, we discuss the applications of such approaches for threatened species management in Australia in the context of climate change, identifying methods of facilitating viability and resilience in the face of extreme environmental stress. Using genomic approaches, conservation management practices such as translocation, targeted gene flow, and gene-editing can now be performed with the express intention of facilitating adaptation to current and projected climate change scenarios in vulnerable species, thus reducing extinction risk and ensuring the protection of our unique biodiversity for future generations. We discuss the current barriers to implementing conservation genomic projects and the efforts being made to overcome them, including communication between researchers and managers to improve the relevance and applicability of genomic studies. We present novel approaches for facilitating adaptive capacity and accelerating natural selection in species to encourage resilience in the face of climate change.
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19
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Kearney MR, Jusup M, McGeoch MA, Kooijman SALM, Chown SL. Where do functional traits come from? The role of theory and models. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13829] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Michael R. Kearney
- School of BioSciences Faculty of Science The University of Melbourne Melbourne Vic. Australia
| | - Marko Jusup
- Tokyo Tech World Hub Research Initiative Institute of Innovative Research Tokyo Institute of Technology Tokyo Japan
| | - Melodie A. McGeoch
- Department of Ecology Environment and Evolution School of Life Sciences La Trobe University Melbourne Vic. Australia
| | | | - Steven L. Chown
- Securing Antarctica's Environmental Future School of Biological Sciences Monash University Melbourne Vic. Australia
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20
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Noakes MJ, McKechnie AE, Brigham RM. Interspecific variation in heat tolerance and evaporative cooling capacity among sympatric temperate-latitude bats. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that interspecific variation in chiropteran heat tolerance and evaporative cooling capacity is correlated with day-roost microclimates, using three vespertilionid bats that occur sympatrically during summer in Saskatchewan, Canada. We predicted that hoary bats (Lasiurus cinereus (Palisot de Beauvois, 1796); ∼22 g) would have higher heat tolerance than little brown bats (Myotis lucifugus (Le Conte, 1831); ∼7 g) and silver-haired bats (Lasionycteris noctivagans (Le Conte, 1831); ∼13 g), as the latter two species roost in tree crevices or cavities that are more thermally buffered than the foliage roosts of hoary bats. We measured core body temperature (Tb; passive integrated transponder tags), evaporative water loss, and resting metabolic rate (flow-through respirometry) while exposing individuals to a stepped profile of increasing air temperature (Ta) from ∼30 °C in ∼2 °C increments. Experiments were terminated when individuals became hyperthermic (Tb ≈ 42.5 °C), with maximum Ta (Ta,max) ranging from 42.0 to 49.7 °C. As predicted, hoary bats had the highest heat tolerance and evaporative cooling capacity, reaching Ta,max ∼2.4 and 1.2 °C higher than little brown and silver-haired bats, respectively. Our results are consistent with the hypothesis that heat tolerance of bats is correlated with roost microclimates, although interspecific variation in body mass and phylogeny may confound these conclusions.
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Affiliation(s)
- Matthew J. Noakes
- Department of Vertebrate Zoology and Ecology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Toruń, Poland
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, Gauteng, 0002, South Africa
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Andrew E. McKechnie
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria, Gauteng, 0001, South Africa
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, Gauteng, 0002, South Africa
| | - R. Mark Brigham
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
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21
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Seasonal Variability of Trends in Regional Hot and Warm Temperature Extremes in Europe. ATMOSPHERE 2021. [DOI: 10.3390/atmos12050612] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Extremely hot or warm weather over the course of the year may have significant impacts on many aspects of human life, the economy, and the natural environment. Until now a thorough assessment of changes of extreme heat or warm events in Europe was hindered by the number of metrics employed, time periods examined, and most studies being conducted in the summer season only. Here, we employ the Extremity Index (EI) to investigate long-term trends in extremely hot or warm days in Europe over the course of the year, with a special focus on their frequency, spatial extent, and intensity. An extreme temperature event (ETE) is defined as a day with an unusually high temperature for a given location and season, even if such a temperature would not be considered extremely high in an absolute sense. The research is conducted in five spatial domains that together cover a large portion of Europe. The period of the most recent 70 years is considered. In all examined regions, mainly significant increasing trends since 1950 are evident for seasonal EI; therefore, also for ETE frequency, intensity, and spatial range. Yet, every region is characterized by its own event pattern, and trends across the continent strongly vary geographically and seasonally. Our study highlights that examined trends of temperature extremes are accelerating and in the last 40 years the rate of change has been even more than three times greater than in the entire study period. The greatest changes were noted for the summer season in Central Europe and Eastern Europe for the most recent 40-year period.
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22
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Animal Harms and Food Production: Informing Ethical Choices. Animals (Basel) 2021; 11:ani11051225. [PMID: 33922738 PMCID: PMC8146968 DOI: 10.3390/ani11051225] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/17/2021] [Accepted: 04/20/2021] [Indexed: 12/14/2022] Open
Abstract
Simple Summary Consideration of animal welfare in food choices has become an influential contemporary theme. Traditional animal welfare views about food have been largely restricted to direct and intentional harms to livestock in intensive animal agriculture settings. However, many harms to animals arising from diverse food production practices in the world are exerted indirectly and unintentionally and often affect wildlife. Here we apply a qualitative analysis of food production by considering the breadth of harms caused by different food production systems to wild as well as domestic animals. Production systems are identified that produce relatively few and relatively many harms. The ethical implications of these findings are discussed for consumers concerned with the broad animal welfare impacts of their food choices. Abstract Ethical food choices have become an important societal theme in post-industrial countries. Many consumers are particularly interested in the animal welfare implications of the various foods they may choose to consume. However, concepts in animal welfare are rapidly evolving towards consideration of all animals (including wildlife) in contemporary approaches such as “One Welfare”. This approach requires recognition that negative impacts (harms) may be intentional and obvious (e.g., slaughter of livestock) but also include the under-appreciated indirect or unintentional harms that often impact wildlife (e.g., land clearing). This is especially true in the Anthropocene, where impacts on non-human life are almost ubiquitous across all human activities. We applied the “harms” model of animal welfare assessment to several common food production systems and provide a framework for assessing the breadth (not intensity) of harms imposed. We considered all harms caused to wild as well as domestic animals, both direct effects and indirect effects. We described 21 forms of harm and considered how they applied to 16 forms of food production. Our analysis suggests that all food production systems harm animals to some degree and that the majority of these harms affect wildlife, not livestock. We conclude that the food production systems likely to impose the greatest overall breadth of harms to animals are intensive animal agriculture industries (e.g., dairy) that rely on a secondary food production system (e.g., cropping), while harvesting of locally available wild plants, mushrooms or seaweed is likely to impose the least harms. We present this conceptual analysis as a resource for those who want to begin considering the complex animal welfare trade-offs involved in their food choices.
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23
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McKechnie AE, Rushworth IA, Myburgh F, Cunningham SJ. Mortality among birds and bats during an extreme heat event in eastern South Africa. AUSTRAL ECOL 2021. [DOI: 10.1111/aec.13025] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Andrew E. McKechnie
- South African Research Chair in Conservation Physiology South African National Biodiversity Institute P.O. Box 754 Pretoria0001South Africa
- DSI‐NRF Centre of Excellence at the FitzPatrick Institute Department of Zoology and Entomology University of Pretoria PretoriaSouth Africa
| | - Ian A. Rushworth
- Ezemvelo KZN Wildlife Pietermaritzburg KwaZulu‐NatalSouth Africa
| | - Ferdi Myburgh
- Ezemvelo KZN Wildlife Pietermaritzburg KwaZulu‐NatalSouth Africa
| | - Susan J. Cunningham
- FitzPatrick Institute of African Ornithology DSI‐NRF Centre of Excellence University of Cape Town Rondebosch South Africa
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24
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Danner RM, Coomes CM, Derryberry EP. Simulated heat waves reduce cognitive and motor performance of an endotherm. Ecol Evol 2021; 11:2261-2272. [PMID: 33717453 PMCID: PMC7920763 DOI: 10.1002/ece3.7194] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 12/07/2020] [Accepted: 12/22/2020] [Indexed: 11/19/2022] Open
Abstract
Heat waves cause mass mortality of animals, including humans, across the globe annually, which has drawn new attention to how animals cope with high air temperatures. Recent field research has explored behavioral responses to high air temperatures, which can influence reproductive success and mortality.Less well studied are the effects of high air temperatures on cognition, which may underlie behavioral changes. Specifically, it is poorly known if cognitive declines occur at high temperatures, and if cognitive and motor components of behavior are similarly affected.We tested how well zebra finches (Taeniopygia guttata castanotis), a model for cognition research, performed two learned foraging tasks (color association and detour-reaching) at mild (22°C) and high (43 and 44°C) air temperatures that occur naturally in their range. We habituated birds to the trial conditions and temperatures on days preceding the test trials and at the trial temperature for 30 min immediately prior to each test trial. Trials lasted less than 10 min. At high air temperatures, zebra finches exhibited heat dissipation behaviors during most tasks, suggesting thermoregulatory challenge.Cognitive performance declined at high air temperatures in two of three measures: Color association was unaffected, but birds missed more food rewards, and did more unproductive behaviors. Motor performance declined at high temperatures on the color association task, including longer times to complete the task, move between food rewards, and process individual seeds. Performance declines varied among components of behavior and among individuals.We combined our behavioral data with existing climate data and predicted that in the austral summer of 2018-2019, zebra finches experienced air temperatures that caused cognitive and motor declines in our captive birds in 34% and 45% of their Australian range, respectively.This study provides novel experimental evidence that high air temperatures cause cognitive and motor performance decline in birds. Further, our results provide insights to how those declines might affect bird ecology and evolution. First, differences in declines among behavioral components may allow identification of behaviors that are most susceptible to decline in the wild. Second, variation in performance declines and heat dissipation behaviors among individuals suggests variability in heat tolerance, which could lead to differential fitness in the wild. Last, these results suggest that high air temperatures cause cognitive declines in the wild and that understanding cognition could help refine predictive models of population persistence.
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Affiliation(s)
- Raymond M. Danner
- Department of Biology and Marine BiologyUniversity of North Carolina WilmingtonWilmingtonNCUSA
| | - Casey M. Coomes
- Department of Ecology and Evolutionary BiologyTulane UniversityNew OrleansLAUSA
- Department of Ecology and Evolutionary BiologyUniversity of TennesseeKnoxvilleTNUSA
| | - Elizabeth P. Derryberry
- Department of Ecology and Evolutionary BiologyTulane UniversityNew OrleansLAUSA
- Department of Ecology and Evolutionary BiologyUniversity of TennesseeKnoxvilleTNUSA
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25
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Fuller A, Mitchell D, Maloney SK, Hetem RS, Fonsêca VFC, Meyer LCR, van de Ven TMFN, Snelling EP. How dryland mammals will respond to climate change: the effects of body size, heat load and a lack of food and water. J Exp Biol 2021; 224:224/Suppl_1/jeb238113. [PMID: 33627465 DOI: 10.1242/jeb.238113] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Mammals in drylands are facing not only increasing heat loads but also reduced water and food availability as a result of climate change. Insufficient water results in suppression of evaporative cooling and therefore increases in body core temperature on hot days, while lack of food reduces the capacity to maintain body core temperature on cold nights. Both food and water shortage will narrow the prescriptive zone, the ambient temperature range over which body core temperature is held relatively constant, which will lead to increased risk of physiological malfunction and death. Behavioural modifications, such as shifting activity between night and day or seeking thermally buffered microclimates, may allow individuals to remain within the prescriptive zone, but can incur costs, such as reduced foraging or increased competition or predation, with consequences for fitness. Body size will play a major role in predicting response patterns, but identifying all the factors that will contribute to how well dryland mammals facing water and food shortage will cope with increasing heat loads requires a better understanding of the sensitivities and responses of mammals exposed to the direct and indirect effects of climate change.
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Affiliation(s)
- Andrea Fuller
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa .,Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.,Centre for Veterinary Wildlife Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa.,School of Human Sciences, Faculty of Science, University of Western Australia, Crawley 6009, WA, Australia
| | - Shane K Maloney
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa.,School of Human Sciences, Faculty of Science, University of Western Australia, Crawley 6009, WA, Australia
| | - Robyn S Hetem
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa.,School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa
| | - Vinicius F C Fonsêca
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa.,Innovation Group of Biometeorology and Animal Welfare (INOBIO-MANERA), Universidade Federal da Paraíba, Areia, 58397000, Brazil
| | - Leith C R Meyer
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa.,Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.,Centre for Veterinary Wildlife Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
| | - Tanja M F N van de Ven
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa
| | - Edward P Snelling
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa.,Centre for Veterinary Wildlife Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.,Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
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26
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Reher S, Dausmann KH. Tropical bats counter heat by combining torpor with adaptive hyperthermia. Proc Biol Sci 2021; 288:20202059. [PMID: 33434466 DOI: 10.1098/rspb.2020.2059] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Many tropical mammals are vulnerable to heat because their water budget limits the use of evaporative cooling for heat compensation. Further increasing temperatures and aridity might consequently exceed their thermoregulatory capacities. Here, we describe two novel modes of torpor, a response usually associated with cold or resource bottlenecks, as efficient mechanisms to counter heat. We conducted a field study on the Malagasy bat Macronycteris commersoni resting in foliage during the hot season, unprotected from environmental extremes. On warm days, the bats alternated between remarkably short micro-torpor bouts and normal resting metabolism within a few minutes. On hot days, the bats extended their torpor bouts over the hottest time of the day while tolerating body temperatures up to 42.9°C. Adaptive hyperthermia combined with lowered metabolic heat production from torpor allows higher heat storage from the environment, negates the need for evaporative cooling and thus increases heat tolerance. However, it is a high-risk response as the torpid bats cannot defend body temperature if ambient temperature increases above a critical/lethal threshold. Torpor coupled with hyperthermia and micro-torpor bouts broaden our understanding of the basic principles of thermal physiology and demonstrate how mammals can perform near their upper thermal limits in an increasingly warmer world.
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Affiliation(s)
- Stephanie Reher
- Functional Ecology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
| | - Kathrin H Dausmann
- Functional Ecology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
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27
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Mo M, Roache M. A review of intervention methods used to reduce flying-fox mortalities in heat stress events. AUSTRALIAN MAMMALOGY 2021. [DOI: 10.1071/am20038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Heat stress events in Australian flying-fox camps have resulted in significant numbers of flying-fox deaths. The frequency and intensity of such events have increased in recent decades, attributed to anthropogenic climate change. Evidence-based interventions are required to address this growing threat. Responders currently use different combinations of a range of intervention methods. We undertook a systematic review of heat stress interventions, which we classified as either ‘camp-scale’ or ‘individual-scale’. Camp-scale interventions included manual and automated misting of roost vegetation, whereas individual-scale interventions included spraying individual animals or removing them for intensive cooling and rehydration procedures. Our study showed that to date, evaluation of the efficacy of heat stress interventions has been largely anecdotal rather than empirical. This highlights the need for dedicated rigorous studies to evaluate the effectiveness of all the intervention methods described here. It will be especially important to understand the relationship between camp temperature and humidity levels and their influence on flying-foxes’ ability to regulate their body temperature, because high relative humidity reduces the ability of mammals to cool themselves using evaporative heat loss. The development of biophysiological measures such as temperature and humidity indices for different flying-fox species would enable meaningful interpretations of intervention trials under controlled conditions.
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Londe DW, Elmore RD, Davis CA, Fuhlendorf SD, Hovick TJ, Luttbeg B, Rutledge J. Weather Influences Multiple Components of Greater Prairie‐Chicken Reproduction. J Wildl Manage 2021. [DOI: 10.1002/jwmg.21957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- David W. Londe
- Department of Natural Resources Ecology and Management Oklahoma State University 008c Ag Hall Stillwater OK 74078 USA
| | - R. Dwayne Elmore
- Department of Natural Resources Ecology and Management Oklahoma State University 008c Ag Hall Stillwater OK 74078 USA
| | - Craig A. Davis
- Department of Natural Resources Ecology and Management Oklahoma State University 008c Ag Hall Stillwater OK 74078 USA
| | - Samuel D. Fuhlendorf
- Department of Natural Resources Ecology and Management Oklahoma State University 008c Ag Hall Stillwater OK 74078 USA
| | - Torre J. Hovick
- Range Science North Dakota State University 201A Morrill Hall Fargo ND 58108 USA
| | - Barney Luttbeg
- Department of Integrative Biology Oklahoma State University 501 Life Science West Stillwater OK 74078 USA
| | - Jimmy Rutledge
- El Coyote Ranch P.O. Box 392 Carrizo Springs TX 78834 USA
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Bourne AR, Ridley AR, McKechnie AE, Spottiswoode CN, Cunningham SJ. Dehydration risk is associated with reduced nest attendance and hatching success in a cooperatively breeding bird, the southern pied babbler Turdoides bicolor. CONSERVATION PHYSIOLOGY 2021; 9:coab043. [PMID: 34150211 PMCID: PMC8208672 DOI: 10.1093/conphys/coab043] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/26/2021] [Accepted: 06/09/2021] [Indexed: 05/12/2023]
Abstract
High air temperatures have measurable negative impacts on reproduction in wild animal populations, including during incubation in birds. Understanding the mechanisms driving these impacts requires comprehensive knowledge of animal physiology and behaviour under natural conditions. We used a novel combination of a non-invasive doubly labelled water (DLW) technique, nest temperature data and field-based behaviour observations to test effects of temperature, rainfall and group size on physiology and behaviour during incubation in southern pied babblers Turdoides bicolor, a cooperatively breeding passerine endemic to the arid savanna regions of southern Africa. The proportion of time that clutches were incubated declined as air temperatures increased, a behavioural pattern traditionally interpreted as a benefit of ambient incubation. However, we show that (i) clutches had a <50% chance of hatching when exposed to daily maximum air temperatures of >35.3°C; (ii) pied babbler groups incubated their nests almost constantly (99% of daylight hours) except on hot days; (iii) operative temperatures in unattended nests frequently exceeded 40.5°C, above which bird embryos are at risk of death; (iv) pied babblers incubating for long periods of time failed to maintain water balance on hot days; and (v) pied babblers from incubating groups lost mass on hot days. These results suggest that pied babblers might leave their nests during hot periods to lower the risk of dehydration associated with prolonged incubation at high operative temperatures. As mean air temperatures increase and extreme heat events become more frequent under climate change, birds will likely incur ever greater thermoregulatory costs of incubation, leading to compromised nest attendance and increased potential for eggs to overheat, with implications for nest success and, ultimately, population persistence.
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Affiliation(s)
- Amanda R Bourne
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Corresponding author: FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.
| | - Amanda R Ridley
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley 6009, Australia
| | - Andrew E McKechnie
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria 0184, South Africa
- DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield 0002, South Africa
| | - Claire N Spottiswoode
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Susan J Cunningham
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
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Cooper CE, Hurley LL, Deviche P, Griffith SC. Physiological responses of wild zebra finches ( Taeniopygia guttata) to heatwaves. J Exp Biol 2020; 223:jeb225524. [PMID: 32376711 DOI: 10.1242/jeb.225524] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 04/30/2020] [Indexed: 12/17/2022]
Abstract
Desert birds inhabit hot, dry environments that are becoming hotter and drier as a consequence of climate change. Extreme weather such as heatwaves can cause mass-mortality events that may significantly impact populations and species. There are currently insufficient data concerning physiological plasticity to inform models of species' response to extreme events and develop mitigation strategies. Consequently, we examine here the physiological plasticity of a small desert bird in response to hot (mean maximum ambient temperature=42.7°C) and cooler (mean maximum ambient temperature=31.4°C) periods during a single Austral summer. We measured body mass, metabolic rate, evaporative water loss and body temperature, along with blood parameters (corticosterone, glucose and uric acid) of wild zebra finches (Taeniopygia guttata) to assess their physiological state and determine the mechanisms by which they respond to heatwaves. Hot days were not significant stressors; they did not result in modification of baseline blood parameters or an inability to maintain body mass, provided drinking water was available. During heatwaves, finches shifted their thermoneutral zone to higher temperatures. They reduced metabolic heat production, evaporative water loss and wet thermal conductance, and increased hyperthermia, especially when exposed to high ambient temperature. A consideration of the significant physiological plasticity that we have demonstrated to achieve more favourable heat and water balance is essential for effectively modelling and planning for the impacts of climate change on biodiversity.
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Affiliation(s)
- Christine Elizabeth Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia 3102, Australia
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Laura Leilani Hurley
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Pierre Deviche
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Simon Charles Griffith
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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Bat thermoregulation in the heat: Limits to evaporative cooling capacity in three southern African bats. J Therm Biol 2020; 89:102542. [PMID: 32364970 DOI: 10.1016/j.jtherbio.2020.102542] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 02/07/2020] [Accepted: 02/13/2020] [Indexed: 12/16/2022]
Abstract
High environmental temperatures pose significant physiological challenges related to energy and water balance for small endotherms. Although there is a growing literature on the effect of high temperatures on birds, comparable data are scarcer for bats. Those data that do exist suggest that roost microsite may predict tolerance of high air temperatures. To examine this possibility further, we quantified the upper limits to heat tolerance and evaporative cooling capacity in three southern African bat species inhabiting the same hot environment but using different roost types (crevice, foliage or cave). We used flow-through respirometry and compared heat tolerance limits (highest air temperature (Ta) tolerated before the onset of severe hyperthermia), body temperature (Tb), evaporative water loss, metabolic rate, and maximum cooling capacity (i.e., evaporative heat loss/metabolic heat production). Heat tolerance limits for the two bats roosting in more exposed sites, Taphozous mauritianus (foliage-roosting) and Eptesicus hottentotus (crevice-roosting), were Ta = ~44 °C and those individuals defended maximum Tb between 41 °C and 43 °C. The heat tolerance limit for the bat roosting in a more buffered site, Rousettus aegyptiacus (cave-roosting), was Ta = ~38 °C with a corresponding Tb of ~38 °C. These interspecific differences, together with a similar trend for higher evaporative cooling efficiency in species occupying warmer roost microsites, add further support to the notion that ecological factors like roost choice may have profound influences on physiological traits related to thermoregulation.
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Turner JM. Facultative hyperthermia during a heatwave delays injurious dehydration of an arboreal marsupial. J Exp Biol 2020; 223:jeb219378. [PMID: 32054679 DOI: 10.1242/jeb.219378] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/05/2020] [Indexed: 01/08/2023]
Abstract
Heatwaves negatively impact wildlife populations and their effects are predicted to worsen with ongoing global warming. Animal mass mortality at extremely high ambient temperature (Ta) is evidence for physiological dysfunction and, to aid conservation efforts, improving our understanding of animal responses to environmental heat is crucial. To address this, I measured the water loss, body temperature and metabolism of an Australian marsupial during a simulated heatwave. The body temperature of the common ringtail possum Pseudocheirus peregrinus increased passively by ∼3°C over a Ta of 29-39°C, conveying water savings of 9.6 ml h-1 When Ta crossed a threshold of 35-36°C, possums began actively cooling by increasing evaporative water loss and thermal conductance. It is clear that facultative hyperthermia is effective up to a point, but once this point is surpassed - the frequency and duration of which are increasing with climate change - body water would rapidly deplete, placing possums in danger of injury or death from dehydration.
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Affiliation(s)
- James M Turner
- Institute for Land, Water and Society, Charles Sturt University, Albury, NSW 2640, Australia
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33
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McKechnie AE, Wolf BO. The Physiology of Heat Tolerance in Small Endotherms. Physiology (Bethesda) 2020; 34:302-313. [PMID: 31389778 DOI: 10.1152/physiol.00011.2019] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Understanding the heat tolerances of small mammals and birds has taken on new urgency with the advent of climate change. Here, we review heat tolerance limits, pathways of evaporative heat dissipation that permit the defense of body temperature during heat exposure, and mechanisms operating at tissue, cellular, and molecular levels.
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Affiliation(s)
- Andrew E McKechnie
- South African Research Chair in Conservation Physiology, National Zoological Garden, South African National Biodiversity Institute, Pretoria, South Africa.,DST-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Blair O Wolf
- UNM Biology Department, University of New Mexico, Albuquerque, New Mexico
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Gunderson AR, Fargevieille A, Warner DA. Egg incubation temperature does not influence adult heat tolerance in the lizard Anolis sagrei. Biol Lett 2020; 16:20190716. [PMID: 31937216 DOI: 10.1098/rsbl.2019.0716] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Extreme heat events are becoming more common as a result of anthropogenic global change. Developmental plasticity in physiological thermal limits could help mitigate the consequences of thermal extremes, but data on the effects of early temperature exposure on thermal limits later in life are rare, especially for vertebrate ectotherms. We conducted an experiment that to our knowledge is the first to isolate the effect of egg (i.e. embryonic) thermal conditions on adult heat tolerance in a reptile. Eggs of the lizard Anolis sagrei were incubated under one of three fluctuating thermal regimes that mimicked natural nest environments and differed in mean and maximum temperatures. After emergence, all hatchlings were raised under common garden conditions until reproductive maturity, at which point heat tolerance was measured. Egg mortality was highest in the warmest treatment, and hatchlings from the warmest treatment tended to have greater mortality than those from the cooler treatments. Despite evidence that incubation temperatures were stressful, we found no evidence that incubation treatment influenced adult heat tolerance. Our results are consistent with a low capacity for organisms to increase their physiological heat tolerance via plasticity, and emphasize the importance of behavioural and evolutionary processes as mechanisms of resilience to extreme heat.
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Affiliation(s)
- Alex R Gunderson
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA 70118, USA
| | | | - Daniel A Warner
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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Ratnayake HU, Welbergen JA, van der Ree R, Kearney MR. Variation in fur properties may explain differences in heat-related mortality among Australian flying-foxes. AUST J ZOOL 2020. [DOI: 10.1071/zo20040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Fur properties play a critical role in the thermoregulation of mammals and are becoming of particular interest as the frequency, intensity, and duration of extreme heat events are increasing under climate change. Australian flying-foxes are known to experience mass die-offs during extreme heat events, yet little is known about how different fur properties affect their thermoregulatory needs. In this study, we examined the differences and patterns in fur properties among and within the four mainland Australian flying-fox species: Pteropus poliocephalus, P. alecto, P. conspicillatus, and P. scapulatus. Using museum specimens, we collected data on fur solar reflectance, fur length and fur depth from the four species across their distribution. We found that P. poliocephalus had significantly longer and deeper fur, and P. alecto had significantly lower fur solar reflectivity, compared with the other species. Across all species, juveniles had deeper fur than adults, and females of P. alecto and P. conspicillatus had deeper fur than males. The biophysical effects of these fur properties are complex and contingent on the degree of exposure to solar radiation, but they may help to explain the relatively higher mortality of P. alecto and of juveniles and females that is commonly observed during extreme heat events.
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Timmiss LA, Martin JM, Murray NJ, Welbergen JA, Westcott D, McKeown A, Kingsford RT. Threatened but not conserved: flying-fox roosting and foraging habitat in Australia. AUST J ZOOL 2020. [DOI: 10.1071/zo20086] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Conservation relies upon a primary understanding of changes in a species’ population size, distribution, and habitat use. Bats represent about one in five mammal species in the world, but understanding for most species is poor. For flying-foxes, specifically the 66 Pteropus species globally, 31 are classified as threatened (Vulnerable, Endangered, Critically Endangered) on the IUCN Red List. Flying-foxes typically aggregate in colonies of thousands to hundreds of thousands of individuals at their roost sites, dispersing at sunset to forage on floral resources (pollen, nectar, and fruit) in nearby environments. However, understanding of flying-fox roosting habitat preferences is poor, hindering conservation efforts in many countries. In this study, we used a database of 654 known roost sites of the four flying-fox species that occur across mainland Australia to determine the land-use categories and vegetation types in which roost sites were found. In addition, we determined the land-use categories and vegetation types found within the surrounding 25 km radius of each roost, representing primary foraging habitat. Surprisingly, for the four species most roosts occurred in urban areas (42–59%, n = 4 species) followed by agricultural areas (21–31%). Critically, for the two nationally listed species, only 5.2% of grey-headed and 13.9% of spectacled flying-fox roosts occurred in habitat within protected areas. Roosts have previously been reported to predominantly occur in rainforest, mangrove, wetland, and dry sclerophyll vegetation types. However, we found that only 20–35% of roosts for each of the four species occurred in these habitats. This study shows that flying-fox roosts overwhelmingly occurred within human-modified landscapes across eastern Australia, and that conservation reserves inadequately protect essential habitat of roosting and foraging flying-foxes.
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Conradie SR, Woodborne SM, Wolf BO, Pessato A, Mariette MM, McKechnie AE. Avian mortality risk during heat waves will increase greatly in arid Australia during the 21st century. CONSERVATION PHYSIOLOGY 2020; 8:coaa048. [PMID: 32523698 PMCID: PMC7271765 DOI: 10.1093/conphys/coaa048] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/15/2020] [Accepted: 05/03/2020] [Indexed: 05/05/2023]
Abstract
Intense heat waves are occurring more frequently, with concomitant increases in the risk of catastrophic avian mortality events via lethal dehydration or hyperthermia. We quantified the risks of lethal hyperthermia and dehydration for 10 Australian arid-zone avifauna species during the 21st century, by synthesizing thermal physiology data on evaporative water losses and heat tolerance limits. We evaluated risks of lethal hyperthermia or exceedance of dehydration tolerance limits in the absence of drinking during the hottest part of the day under recent climatic conditions, compared to those predicted for the end of this century across Australia. Increases in mortality risk via lethal dehydration and hyperthermia vary among the species modelled here but will generally increase greatly, particularly in smaller species (~10-42 g) and those inhabiting the far western parts of the continent. By 2100 CE, zebra finches' potential exposure to acute lethal dehydration risk will reach ~ 100 d y-1 in the far northwest of Australia and will exceed 20 d y-1 over > 50% of this species' current range. Risks of dehydration and hyperthermia will remain much lower for large non-passerines such as crested pigeons. Risks of lethal hyperthermia will also increase substantially for smaller species, particularly if they are forced to visit exposed water sources at very high air temperatures to avoid dehydration. An analysis of atlas data for zebra finches suggests that population declines associated with very hot conditions are already occurring in the hottest areas. Our findings suggest that the likelihood of persistence within current species ranges, and the potential for range shifts, will become increasingly constrained by temperature and access to drinking water. Our model adds to an increasing body of literature suggesting that arid environments globally will experience considerable losses of avifauna and biodiversity under unmitigated climate change scenarios.
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Affiliation(s)
- Shannon R Conradie
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, 2 Cussonia Ave, Brummeria, Pretoria 0184, South Africa
- DST-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Lynnwood Rd., Pretoria 0002, South Africa
| | - Stephan M Woodborne
- iThemba LABS, Johannesburg, 514 Empire Rd, Johannesburg 2193, South Africa
- Mammal Research Institute, University of Pretoria, Lynnwood Rd., Pretoria 0002, South Africa
| | - Blair O Wolf
- UNM Biology Department, University of New Mexico, Albuquerque, NM 87131, U.S.A
| | - Anaïs Pessato
- Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, 75 Pigdons Road, Waurn Ponds VIC 3216, Australia
| | - Mylene M Mariette
- Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, 75 Pigdons Road, Waurn Ponds VIC 3216, Australia
| | - Andrew E McKechnie
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, 2 Cussonia Ave, Brummeria, Pretoria 0184, South Africa
- DST-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Lynnwood Rd., Pretoria 0002, South Africa
- Corresponding author: South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, South Africa.
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Armstrong KN, Clarke S, Linke A, Scanlon A, Roetman P, Wilson J, Hitch AT, Donnellan SC. Citizen science implements the first intensive acoustics-based survey of insectivorous bat species across the Murray–Darling Basin of South Australia. AUST J ZOOL 2020. [DOI: 10.1071/zo20051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Effective land management and biodiversity conservation policy relies on good records of native species occurrence and habitat association, but for many animal groups these data are inadequate. In the Murray–Darling Basin (MDB), the most environmentally and economically important catchment in Australia, knowledge gaps exist on the occurrence and habitat associations of insectivorous bat species. We relied on the interest and effort of citizen scientists to assist with the most intensive insectivorous bat survey ever undertaken in the MDB region of South Australia. We used an existing network of Natural Resource Management groups to connect interested citizens and build on historical observations of bat species using a fleet of 30 Anabat Swift bat detectors. The survey effort more than doubled the number of bat occurrence records for the area in two years (3000 records; cf. 2693 records between 1890 and 2018; freely available through the Atlas of Living Australia). We used multinomial logistic regression to look at the relationship between three types of environmental covariates: flight space, nearest open water source and vegetation type. There were no differences in species richness among the environmental covariates. The records have been, and will continue to be, used to inform government land management policy, more accurately predict the impact of development proposals on bat populations, and update conservation assessments for microbat species. A social survey tool also showed that participation in the project led to positive behaviours, and planned positive behaviours, for improving bat habitat on private land.
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Cooper CE, Withers PC, Hurley LL, Griffith SC. The Field Metabolic Rate, Water Turnover, and Feeding and Drinking Behavior of a Small Avian Desert Granivore During a Summer Heatwave. Front Physiol 2019; 10:1405. [PMID: 31824330 PMCID: PMC6879461 DOI: 10.3389/fphys.2019.01405] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 10/31/2019] [Indexed: 11/30/2022] Open
Abstract
Global environmental change is leading to an increase in the frequency, intensity, and duration of extreme weather events, so effective environmental management requires an understanding not only of the physiological response of organisms to increased mean temperatures, but also to extreme environmental conditions. To determine the physiological consequences of heatwaves on energy and water balance of arid-adapted zebra finches (Taeniopygia guttata), we measured field metabolic rate and water turnover rate of wild, free-living finches during a heatwave (consecutive days of maximum ambient temperature of 40–45°C) and during a cooler period (maximum ambient temperature of 28°C) during a summer drought. To understand how birds accommodated their energy and water requirements, we also monitored feeding and drinking behavior of zebra finches at the study site on hot and cold days over 2.5 months during the same summer. Zebra finches can accommodate heatwaves without major impacts on field energy or water turnover, even when the heatwave is superimposed on high summer temperatures and long-term drought, so long as drinking water is available. In fact, cooler periods may pose a greater energetic challenge than heatwaves during drought, when food availability is limited, due to the increased thermoregulatory cost of maintaining a high body temperature against a thermal gradient. Zebra finches avoided or limited activity during the most thermally challenging periods of the day. Their pre-emptive feeding and drinking in preparation for hours of relative inactivity at high ambient temperature, together with a high body water content and reduced midday activity and metabolic heat production, enabled zebra finches to maintain body mass during a heatwave. Predicting upcoming periods of unfavorably high ambient temperature, together with a high body water content, may be essential for survival by desert birds of extreme ambient temperature during heatwaves.
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Affiliation(s)
- Christine Elizabeth Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, WA, Australia.,Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.,School of Biological Sciences, University of Western Australia, Perth, WA, Australia
| | - Philip Carew Withers
- School of Molecular and Life Sciences, Curtin University, Perth, WA, Australia.,School of Biological Sciences, University of Western Australia, Perth, WA, Australia
| | | | - Simon Charles Griffith
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.,School of Biological, Earth, and Environmental Sciences, University of New South Wales Sydney, Sydney, NSW, Australia
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40
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Zduniak M, Pillay N, Schradin C. Basking African striped mice choose warmer locations to heat up: evidence from a field study. J Zool (1987) 2019. [DOI: 10.1111/jzo.12687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Zduniak
- Department of Systematic Zoology Adam Mickiewicz University Poznań Poland
- School of Animal, Plant and Environmental Sciences University of the Witwatersrand Johannesburg South Africa
| | - N. Pillay
- School of Animal, Plant and Environmental Sciences University of the Witwatersrand Johannesburg South Africa
| | - C. Schradin
- School of Animal, Plant and Environmental Sciences University of the Witwatersrand Johannesburg South Africa
- IPHC, UNISTRA, CNRS Strasbourg France
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