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Goh G, Vesterdorf K, Fuller A, Blache D, Maloney SK. Optimal sampling interval for characterisation of the circadian rhythm of body temperature in homeothermic animals using periodogram and cosinor analysis. Ecol Evol 2024; 14:e11243. [PMID: 38601852 PMCID: PMC11004550 DOI: 10.1002/ece3.11243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 03/19/2024] [Accepted: 03/25/2024] [Indexed: 04/12/2024] Open
Abstract
Core body temperature (T c) is a critical aspect of homeostasis in birds and mammals and is increasingly used as a biomarker of the fitness of an animal to its environment. Periodogram and cosinor analysis can be used to estimate the characteristics of the circadian rhythm of T c from data obtained on loggers that have limited memory capacity and battery life. The sampling interval can be manipulated to maximise the recording period, but the impact of sampling interval on the output of periodogram or cosinor analysis is unknown. Some basic guidelines are available from signal analysis theory, but those guidelines have never been tested on T c data. We obtained data at 1-, 5- or 10-min intervals from nine avian or mammalian species, and re-sampled those data to simulate logging at up to 240-min intervals. The period of the rhythm was first analysed using the Lomb-Scargle periodogram, and the mesor, amplitude, acrophase and adjusted coefficient of determination (R 2) from the original and the re-sampled data were obtained using cosinor analysis. Sampling intervals longer than 60 min did not affect the average mesor, amplitude, acrophase or adjusted R 2, but did impact the estimation of the period of the rhythm. In most species, the period was not detectable when intervals longer than 120 min were used. In all individual profiles, a 30-min sampling interval modified the values of the mesor and amplitude by less than 0.1°C, and the adjusted R 2 by less than 0.1. At a 30-min interval, the acrophase was accurate to within 15 min for all species except mice. The adjusted R 2 increased as sampling frequency decreased. In most cases, a 30-min sampling interval provides a reliable estimate of the circadian T c rhythm using periodogram and cosinor analysis. Our findings will help biologists to select sampling intervals to fit their research goals.
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Affiliation(s)
- Grace Goh
- School of Human SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Kristine Vesterdorf
- School of Human SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Andrea Fuller
- Brain Function Research Group, School of Physiology, Faculty of Health SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
| | - Dominique Blache
- School of Agriculture and EnvironmentThe University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Shane K. Maloney
- School of Human SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
- Brain Function Research Group, School of Physiology, Faculty of Health SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
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2
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Geiser F, Ruf T. Long-term survival, temperature, and torpor patterns. Sci Rep 2023; 13:6673. [PMID: 37095170 PMCID: PMC10126141 DOI: 10.1038/s41598-023-33646-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/17/2023] [Indexed: 04/26/2023] Open
Abstract
Mammalian and avian torpor is highly effective in reducing energy expenditure. However, the extent of energy savings achieved and thus long-term survival appear to differ between species capable of multiday hibernation and species restricted to daily heterothermy, which could, however, be due to thermal effects. We tested how long-term survival on stored body fat (i.e. time to lean body mass), crucial for overcoming adverse periods, is related to the pattern of torpor expressed under different ambient temperatures (Ta: 7 °C typical of hibernation, 15 and 22 °C typical of daily torpor) in the small marsupial hibernator the pygmy-possum (Cercartetus nanus). Possums expressed torpor at all Tas and survived without food for 310 days on average at Ta 7 °C, 195 days at Ta 15 °C, and 127 days at Ta 22 °C. At Ta 7 and 15 °C, torpor bout duration (TBD) increased from < 1-3 to ~ 5-16 days over 2 months, whereas at Ta 22 °C, TBD remained at < 1 to ~ 2 days. At all Tas daily energy use was substantially lower and TBD and survival times of possums much longer (3-12 months) than in daily heterotherms (~ 10 days). Such pronounced differences in torpor patterns and survival times even under similar thermal conditions provide strong support for the concept that torpor in hibernators and daily heterotherms are physiologically distinct and have evolved for different ecological purposes.
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Affiliation(s)
- Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, 2351, Australia
| | - Thomas Ruf
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Savoyenstrasse 1, 1160, Vienna, Austria.
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3
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Welman S, Jastroch M, Mzilikazi N. Obligatory homeothermy of mesic adapted African striped mice, Rhabdomys pumilio, is governed by seasonal basal metabolism and year-round "thermogenic readiness" of brown adipose tissue. J Exp Biol 2022; 225:275893. [PMID: 35694963 DOI: 10.1242/jeb.243860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 06/08/2022] [Indexed: 11/20/2022]
Abstract
Small mammals undergo thermoregulatory adjustments in response to changing environmental conditions. Whereas small heterothermic mammals can employ torpor to save energy in the cold, homeothermic species must increase heat production to defend normothermia through the recruitment of brown adipose tissue (BAT). Here, we studied thermoregulatory adaptation in an obligate homeotherm, the African striped mouse (Rhabdomys pumilio), captured from a subpopulation living in a mesic, temperate climate with marked seasonal differences. Basal metabolic rate (BMR), non-shivering thermogenesis (NST) and summit metabolic rate (MSUM) increased from summer to winter, with NST and MSUM already reaching maximal rates in autumn, suggesting seasonal preparation to the cold. Typical of rodents, cold-induced metabolic rates positively correlate with BAT mass. Analysis of cytochrome c oxidase (COX) activity and UCP1 content, however, demonstrate that thermogenic capacity declines with BAT mass. This resulted in seasonal differences in NST being driven by changes in BMR. The increase in BMR is supported by a comprehensive anatomical analysis of metabolically active organs, revealing increased mass proportions in the cold season. The thermoregulatory response of R. pumilio is associated with the maintenance of body weight throughout the year (48.3±1.4 g), contrasting large summer-winter mass reductions often observed in Holarctic rodents. Collectively, bioenergetic adaptation of this Afrotropical rodent involves seasonal organ adjustments influencing BMR, combined with a constant thermogenic capacity dictated by trade-offs in thermogenic properties of BAT. Arguably, this high degree of plasticity was a response to unpredictable cold spells throughout the year. Consequently, the reliance on such a resource intensive thermoregulatory strategy may expose more energetic vulnerability in changing environments of food scarcity and extreme weather conditions due to climate change, with major ramifications for survival of the species.
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Affiliation(s)
- Shaun Welman
- Department of Zoology, Nelson Mandela University, Gqeberha, South Africa
| | - Martin Jastroch
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden.,Institute for Diabetes and Obesity, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany
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4
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Reher S, Rabarison H, Nowack J, Dausmann KH. Limited Physiological Compensation in Response to an Acute Microclimate Change in a Malagasy Bat. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.779381] [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
Rapid environmental changes are challenging for endothermic species because they have direct and immediate impacts on their physiology by affecting microclimate and fundamental resource availability. Physiological flexibility can compensate for certain ecological perturbations, but our basic understanding of how species function in a given habitat and the extent of their adaptive scope is limited. Here we studied the effect of acute, experimental microclimate change on the thermal physiology of two populations of the widespread Malagasy bat, Macronycteris commersoni. Populations of this species are found roosting under contrasting conditions, i.e., in a constant hot and humid cave or below foliage unprotected from fluctuations in ambient conditions. We exposed free-ranging individuals of each population to the respective opposite condition and thus to novel microclimate within an ecologically realistic scope while measuring metabolic rate and skin temperature. Cave bats in forest setting had a limited capacity to maintain euthermia to the point that two individuals became hypothermic when ambient temperature dropped below their commonly experienced cave temperature. Forest bats on the other hand, had difficulties to dissipate heat in the humid cave set-up. The response to heat, however, was surprisingly uniform and all bats entered torpor combined with hyperthermia at temperatures exceeding their thermoneutral zone. Thus, while we observed potential for flexible compensation of heat through “hot” torpor, both populations showed patterns suggestive of limited potential to cope with acute microclimate changes deviating from their typically occupied roosts. Our study emphasizes that intraspecific variation among populations could be misleading when assessing species’ adaptive scopes, as variation may arise from genetic adaptation, developmental plasticity or phenotypic flexibility, all of which allow for compensatory responses at differing time scales. Disentangling these mechanisms and identifying the basis of variation is vital to make accurate predictions of species’ chances for persisting in ever rapidly changing habitats and climates.
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5
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Jolly CJ, Dickman CR, Doherty TS, van Eeden LM, Geary WL, Legge SM, Woinarski JCZ, Nimmo DG. Animal mortality during fire. GLOBAL CHANGE BIOLOGY 2022; 28:2053-2065. [PMID: 34989061 DOI: 10.1111/gcb.16044] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 12/04/2021] [Indexed: 06/14/2023]
Abstract
Earth's rapidly warming climate is propelling us towards an increasingly fire-prone future. Currently, knowledge of the extent and characteristics of animal mortality rates during fire remains rudimentary, hindering our ability to predict how animal populations may be impacted in the future. To address this knowledge gap, we conducted a global systematic review of the direct effects of fire on animal mortality rates, based on studies that unequivocally determined the fate of animals during fire. From 31 studies spanning 1984-2020, we extracted data on the direct impacts of fire on the mortality of 31 species from 23 families. From these studies, there were 43 instances where direct effects were measured by reporting animal survival from pre- to post-fire. Most studies were conducted in North America (52%) and Oceania (42%), focused largely on mammals (53%) and reptiles (30%), and reported mostly on animal survival in planned (82%) and/or low severity (70%) fires. We found no studies from Asia, Europe or South America. Although there were insufficient data to conduct a formal meta-analysis, we tested the effect of fire type, fire severity, fire regime, animal body mass, ecological attributes and class on survival. Only fire severity affected animal mortality, with a higher proportion of animals being killed by high than low severity fires. Recent catastrophic fires across the globe have drawn attention to the plight of animals exposed to wildfire. Yet, our systematic review suggests that a relatively low proportion of animals (mean predicted mortality [95% CI] = 3% [1%-9%]) are killed during fire. However, our review also underscores how little we currently know about the direct effects of fire on animal mortality, and highlights the critical need to understand the effects of high severity fire on animal populations.
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Affiliation(s)
- Chris J Jolly
- Institute for Land, Water and Society, School of Environmental Science, Charles Sturt University, Albury, New South Wales, Australia
| | - Chris R Dickman
- National Environmental Science Program Threatened Species Recovery Hub, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Tim S Doherty
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Lily M van Eeden
- Department of Environment Land, Water and Planning, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia
| | - William L Geary
- Department of Environment, Land, Water and Planning, Biodiversity Strategy and Knowledge Branch, Biodiversity Division, East Melbourne, Victoria, Australia
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
| | - Sarah M Legge
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
- Centre for Biodiversity and Conservation Science, University of Queensland, St Lucia, Queensland, Australia
- Fenner School of Environment and Society, The Australian National University, Australian Capital Territory, Canberra, Australia
| | - John C Z Woinarski
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
- School of Ecosystem and Forest Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Dale G Nimmo
- Institute for Land, Water and Society, School of Environmental Science, Charles Sturt University, Albury, New South Wales, Australia
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6
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During MAD, Smit J, Voeten DFAE, Berruyer C, Tafforeau P, Sanchez S, Stein KHW, Verdegaal-Warmerdam SJA, van der Lubbe JHJL. The Mesozoic terminated in boreal spring. Nature 2022; 603:91-94. [PMID: 35197634 PMCID: PMC8891016 DOI: 10.1038/s41586-022-04446-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 01/19/2022] [Indexed: 12/26/2022]
Abstract
The Cretaceous-Palaeogene mass extinction around 66 million years ago was triggered by the Chicxulub asteroid impact on the present-day Yucatán Peninsula1,2. This event caused the highly selective extinction that eliminated about 76% of species3,4, including all non-avian dinosaurs, pterosaurs, ammonites, rudists and most marine reptiles. The timing of the impact and its aftermath have been studied mainly on millennial timescales, leaving the season of the impact unconstrained. Here, by studying fishes that died on the day the Mesozoic era ended, we demonstrate that the impact that caused the Cretaceous-Palaeogene mass extinction took place during boreal spring. Osteohistology together with stable isotope records of exceptionally preserved perichondral and dermal bones in acipenseriform fishes from the Tanis impact-induced seiche deposits5 reveal annual cyclicity across the final years of the Cretaceous period. Annual life cycles, including seasonal timing and duration of reproduction, feeding, hibernation and aestivation, vary strongly across latest Cretaceous biotic clades. We postulate that the timing of the Chicxulub impact in boreal spring and austral autumn was a major influence on selective biotic survival across the Cretaceous-Palaeogene boundary.
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Affiliation(s)
- Melanie A D During
- Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands. .,Subdepartment of Evolution and Development, Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
| | - Jan Smit
- Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Dennis F A E Voeten
- Subdepartment of Evolution and Development, Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.,European Synchrotron Radiation Facility, Grenoble, France
| | | | - Paul Tafforeau
- European Synchrotron Radiation Facility, Grenoble, France
| | - Sophie Sanchez
- Subdepartment of Evolution and Development, Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.,European Synchrotron Radiation Facility, Grenoble, France
| | - Koen H W Stein
- Royal Belgian Institute of Natural Sciences, Directorate 'Earth and History of Life', Brussels, Belgium.,Earth System Science-AMGC, Vrije Universiteit Brussel, Brussels, Belgium
| | | | - Jeroen H J L van der Lubbe
- Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.,School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
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7
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Grigg G, Nowack J, Bicudo JEPW, Bal NC, Woodward HN, Seymour RS. Whole-body endothermy: ancient, homologous and widespread among the ancestors of mammals, birds and crocodylians. Biol Rev Camb Philos Soc 2021; 97:766-801. [PMID: 34894040 PMCID: PMC9300183 DOI: 10.1111/brv.12822] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/25/2021] [Accepted: 11/29/2021] [Indexed: 12/31/2022]
Abstract
The whole‐body (tachymetabolic) endothermy seen in modern birds and mammals is long held to have evolved independently in each group, a reasonable assumption when it was believed that its earliest appearances in birds and mammals arose many millions of years apart. That assumption is consistent with current acceptance that the non‐shivering thermogenesis (NST) component of regulatory body heat originates differently in each group: from skeletal muscle in birds and from brown adipose tissue (BAT) in mammals. However, BAT is absent in monotremes, marsupials, and many eutherians, all whole‐body endotherms. Indeed, recent research implies that BAT‐driven NST originated more recently and that the biochemical processes driving muscle NST in birds, many modern mammals and the ancestors of both may be similar, deriving from controlled ‘slippage’ of Ca2+ from the sarcoplasmic reticulum Ca2+‐ATPase (SERCA) in skeletal muscle, similar to a process seen in some fishes. This similarity prompted our realisation that the capacity for whole‐body endothermy could even have pre‐dated the divergence of Amniota into Synapsida and Sauropsida, leading us to hypothesise the homology of whole‐body endothermy in birds and mammals, in contrast to the current assumption of their independent (convergent) evolution. To explore the extent of similarity between muscle NST in mammals and birds we undertook a detailed review of these processes and their control in each group. We found considerable but not complete similarity between them: in extant mammals the ‘slippage’ is controlled by the protein sarcolipin (SLN), in birds the SLN is slightly different structurally and its role in NST is not yet proved. However, considering the multi‐millions of years since the separation of synapsids and diapsids, we consider that the similarity between NST production in birds and mammals is consistent with their whole‐body endothermy being homologous. If so, we should expect to find evidence for it much earlier and more widespread among extinct amniotes than is currently recognised. Accordingly, we conducted an extensive survey of the palaeontological literature using established proxies. Fossil bone histology reveals evidence of sustained rapid growth rates indicating tachymetabolism. Large body size and erect stature indicate high systemic arterial blood pressures and four‐chambered hearts, characteristic of tachymetabolism. Large nutrient foramina in long bones are indicative of high bone perfusion for rapid somatic growth and for repair of microfractures caused by intense locomotion. Obligate bipedality appeared early and only in whole‐body endotherms. Isotopic profiles of fossil material indicate endothermic levels of body temperature. These proxies led us to compelling evidence for the widespread occurrence of whole‐body endothermy among numerous extinct synapsids and sauropsids, and very early in each clade's family tree. These results are consistent with and support our hypothesis that tachymetabolic endothermy is plesiomorphic in Amniota. A hypothetical structure for the heart of the earliest endothermic amniotes is proposed. We conclude that there is strong evidence for whole‐body endothermy being ancient and widespread among amniotes and that the similarity of biochemical processes driving muscle NST in extant birds and mammals strengthens the case for its plesiomorphy.
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Affiliation(s)
- Gordon Grigg
- School of Biological Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Julia Nowack
- School of Biological and Environmental Sciences, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool, L3 3AF, U.K
| | | | | | - Holly N Woodward
- Oklahoma State University Center for Health Sciences, Tulsa, OK, 74107, U.S.A
| | - Roger S Seymour
- School of Biological Sciences, University of Adelaide, Adelaide, SA, 5005, Australia
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8
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Levesque DL, Nowack J, Boyles JG. Body Temperature Frequency Distributions: A Tool for Assessing Thermal Performance in Endotherms? Front Physiol 2021; 12:760797. [PMID: 34721082 PMCID: PMC8551754 DOI: 10.3389/fphys.2021.760797] [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: 08/18/2021] [Accepted: 09/07/2021] [Indexed: 12/25/2022] Open
Abstract
There is increasing recognition that rather than being fully homeothermic, most endotherms display some degree of flexibility in body temperature. However, the degree to which this occurs varies widely from the relatively strict homeothermy in species, such as humans to the dramatic seasonal hibernation seen in Holarctic ground squirrels, to many points in between. To date, attempts to analyse this variability within the framework generated by the study of thermal performance curves have been lacking. We tested if frequency distribution histograms of continuous body temperature measurements could provide a useful analogue to a thermal performance curve in endotherms. We provide examples from mammals displaying a range of thermoregulatory phenotypes, break down continuous core body temperature traces into various components (active and rest phase modes, spreads and skew) and compare these components to hypothetical performance curves. We did not find analogous patterns to ectotherm thermal performance curves, in either full datasets or by breaking body temperature values into more biologically relevant components. Most species had either bimodal or right-skewed (or both) distributions for both active and rest phase body temperatures, indicating a greater capacity for mammals to tolerate body temperatures elevated above the optimal temperatures than commonly assumed. We suggest that while core body temperature distributions may prove useful in generating optimal body temperatures for thermal performance studies and in various ecological applications, they may not be a good means of assessing the shape and breath of thermal performance in endotherms. We also urge researchers to move beyond only using mean body temperatures and to embrace the full variability in both active and resting temperatures in endotherms.
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Affiliation(s)
- D L Levesque
- School of Biology and Ecology, University of Maine, Orono, ME, United States
| | - J Nowack
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - J G Boyles
- Cooperative Wildlife Research Laboratory, Center for Ecology, and School of Biological Sciences, Southern Illinois University, Carbondale, IL, United States
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9
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Nimmo DG, Carthey AJR, Jolly CJ, Blumstein DT. Welcome to the Pyrocene: Animal survival in the age of megafire. GLOBAL CHANGE BIOLOGY 2021; 27:5684-5693. [PMID: 34404117 DOI: 10.1111/gcb.15834] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/11/2021] [Accepted: 07/17/2021] [Indexed: 06/13/2023]
Abstract
Planet Earth is entering the age of megafire, pushing ecosystems to their limits and beyond. While fire causes mortality of animals across vast portions of the globe, scientists are only beginning to consider fire as an evolutionary force in animal ecology. Here, we generate a series of hypotheses regarding animal responses to fire by adopting insights from the predator-prey literature. Fire is a lethal threat; thus, there is likely strong selection for animals to recognize the olfactory, auditory, and visual cues of fire, and deploy fire avoidance behaviours that maximize survival probability. If fire defences are costly, it follows that intraspecific variation in fire avoidance behaviours should correspond with variation in fire behaviour and regimes. Species and populations inhabiting ecosystems that rarely experience fire may lack these traits, placing 'fire naive' populations and species at enhanced extinction risk as the distribution of fire extends into new ecosystem types. We outline a research agenda to understand behavioural responses to fire and to identify conservation interventions that could be used to overcome fire naivety.
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Affiliation(s)
- Dale G Nimmo
- Institute of Land, Water and Society, School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Albury, New South Wales, Australia
| | - Alexandra J R Carthey
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Chris J Jolly
- Institute of Land, Water and Society, School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Albury, New South Wales, Australia
| | - Daniel T Blumstein
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
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10
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Andersen AN. Faunal responses to fire in Australian tropical savannas: Insights from field experiments and their lessons for conservation management. DIVERS DISTRIB 2020. [DOI: 10.1111/ddi.13198] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Alan N. Andersen
- Research Institute for the Environment and Livelihoods Charles Darwin University Darwin NT Australia
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11
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Nowack J, Levesque DL, Reher S, Dausmann KH. Variable Climates Lead to Varying Phenotypes: “Weird” Mammalian Torpor and Lessons From Non-Holarctic Species. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00060] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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12
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Turbill C, McAllan BM, Prior S. Thermal energetics and behaviour of a small, insectivorous marsupial in response to the interacting risks of starvation and predation. Oecologia 2019; 191:803-815. [DOI: 10.1007/s00442-019-04542-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 10/22/2019] [Indexed: 11/27/2022]
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13
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Abstract
Abstract
Tachyglossus aculeatus (Shaw, 1792) is a monotreme commonly called the short-beaked echidna. Although considered Australia’s most common native mammal because of its continent-wide distribution, its population numbers everywhere are low. It is easily distinguished from all other native Australian mammals because of its spine-covered body, hairless beak, and unique “rolling” gait. The five subspecies, one of which is found in Papua New Guinea, show variations in fur density, spine diameter, length, and number of grooming claws. The Kangaroo Island short-beaked echidna Tachyglossus aculeatus multiaculeatus is listed as “Endangered” but all other Tachyglossus are listed as “Least Concern” in the 2016 International Union for Conservation of Nature and Natural Resources Red List.
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Affiliation(s)
- Peggy D Rismiller
- Pelican Lagoon Research & Wildlife Centre, Penneshaw, South Australia, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Frank Grutzner
- The Environment Institute, The University of Adelaide, Adelaide, South Australia, Australia
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14
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Simms A, Scott M, Watson S, Leonard S. Attenuated post-fire fauna succession: the effects of surrounding landscape context on post-fire colonisation of fauna. WILDLIFE RESEARCH 2019. [DOI: 10.1071/wr18131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
After fire, immigration from outside burnt areas is important for the recovery of faunal communities. However, for recovery to occur, the matrix around the fire must support source populations of immigrants. Therefore, the landscape context of fires may be a critical determinant of the species pool available for (re)colonisation, hence post-fire community composition. Increasingly, fires occur in fragmented systems, and there is limited knowledge of how the surrounding landscape interacts with post-fire community recovery.
Aim
The present study aimed to examine how landscape context influences faunal communities after large wildfires.
Methods
Three reserves burnt by wildfire were examined ~18 months before the study in the Mallee region of south-eastern Australia. In all cases the burnt area consisted of natural mallee woodland. Two fires occurred within a matrix of extensive natural vegetation, while the third fire burnt >80% of a reserve situated within a highly fragmented, largely agricultural landscape. Birds, reptiles and mammals were surveyed at 90 sites inside and outside the fire boundaries, and relationships of species occurrence to reserve location, burnt versus unburnt status and distance from fire edge were all examined.
Key results
Post-fire faunal communities reflected the species in the surrounding unburnt landscape. Notably, open habitat specialists, invasive species and species that can persist in small habitat patches were prominent within the fragmented system. Post-fire fauna communities were also influenced by variation of the natural vegetation surrounding the fire. The occurrence of species with low dispersal ability (i.e. reptiles) was influenced by local (patch scale) vegetation structure.
2Conclusions
The landscape context of fires is a major driver of the composition of post-fire faunal communities. Our results highlight the potential loss of species sensitive to fragmentation from fire-prone natural vegetation within modified landscapes, and that a reduced pool of potential immigrants leads to ‘attenuated succession’, compromising recovery of the pre-fire community.
Implications
Post-fire colonists reflect the surrounding landscapes species pool, such that reserves surrounded by fragmented or otherwise low quality habitat are at risk of attenuated succession after fire. Landscape context should be incorporated into conservation planning in fire-prone ecosystems, including consideration of surrounding habitat quality and connectivity and protecting long unburnt vegetation.
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15
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Nimmo DG, Avitabile S, Banks SC, Bliege Bird R, Callister K, Clarke MF, Dickman CR, Doherty TS, Driscoll DA, Greenville AC, Haslem A, Kelly LT, Kenny SA, Lahoz‐Monfort JJ, Lee C, Leonard S, Moore H, Newsome TM, Parr CL, Ritchie EG, Schneider K, Turner JM, Watson S, Westbrooke M, Wouters M, White M, Bennett AF. Animal movements in fire‐prone landscapes. Biol Rev Camb Philos Soc 2018; 94:981-998. [DOI: 10.1111/brv.12486] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/08/2018] [Accepted: 11/14/2018] [Indexed: 01/14/2023]
Affiliation(s)
- Dale G. Nimmo
- School of Environmental Science Institute for Land, Water and Society, Charles Sturt University Albury New South Wales 2640 Australia
| | - Sarah Avitabile
- Department of Ecology, Environment and Evolution, School of Life Sciences La Trobe University Bundoora Victoria 3086 Australia
| | - Sam C. Banks
- Research Institute for the Environment and Livelihoods, College of Engineering, IT and the Environment, Charles Darwin University Casuarina Northern Territory 0810 Australia
| | - Rebecca Bliege Bird
- Department of Anthropology Pennsylvania State University University Park PA 16802 U.S.A
| | - Kate Callister
- Department of Ecology, Environment and Evolution, School of Life Sciences La Trobe University Bundoora Victoria 3086 Australia
| | - Michael F. Clarke
- Department of Ecology, Environment and Evolution, School of Life Sciences La Trobe University Bundoora Victoria 3086 Australia
- Research Centre for Future Landscapes, La Trobe University Bundoora Victoria 3086 Australia
| | - Chris R. Dickman
- School of Life and Environmental Sciences University of Sydney Sydney New South Wales 2006 Australia
| | - Tim S. Doherty
- School of Life and Environmental Sciences Centre for Integrative Ecology (Burwood campus), Deakin University Geelong Victoria 3220 Australia
| | - Don A. Driscoll
- School of Life and Environmental Sciences Centre for Integrative Ecology (Burwood campus), Deakin University Geelong Victoria 3220 Australia
| | - Aaron C. Greenville
- School of Life and Environmental Sciences University of Sydney Sydney New South Wales 2006 Australia
| | - Angie Haslem
- Department of Ecology, Environment and Evolution, School of Life Sciences La Trobe University Bundoora Victoria 3086 Australia
| | - Luke T. Kelly
- School of Ecosystem and Forest Sciences The University of Melbourne Parkville Victoria 3010 Australia
| | - Sally A. Kenny
- Victorian Department of Environment, Land Water & Planning Arthur Rylah Institute for Environmental Research 123 Brown St, Heidelberg Victoria 3081 Australia
| | - José J. Lahoz‐Monfort
- School of Ecosystem and Forest Sciences The University of Melbourne Parkville Victoria 3010 Australia
| | - Connie Lee
- School of Life and Environmental Sciences Centre for Integrative Ecology (Burwood campus), Deakin University Geelong Victoria 3220 Australia
| | - Steven Leonard
- Department of Ecology, Environment and Evolution, School of Life Sciences La Trobe University Bundoora Victoria 3086 Australia
| | - Harry Moore
- School of Environmental Science Institute for Land, Water and Society, Charles Sturt University Albury New South Wales 2640 Australia
| | - Thomas M. Newsome
- School of Life and Environmental Sciences University of Sydney Sydney New South Wales 2006 Australia
| | - Catherine L. Parr
- School of Environmental Sciences University of Liverpool Liverpool L69 3GP U.K
- Department of Zoology & Entomology University of Pretoria Pretoria 0002 South Africa
- School of Animal, Plant and Environmental Sciences University of the Witwatersrand Wits 2050 South Africa
| | - Euan G. Ritchie
- School of Life and Environmental Sciences University of Sydney Sydney New South Wales 2006 Australia
| | | | - James M. Turner
- School of Environmental Science Institute for Land, Water and Society, Charles Sturt University Albury New South Wales 2640 Australia
| | - Simon Watson
- Department of Ecology, Environment and Evolution, School of Life Sciences La Trobe University Bundoora Victoria 3086 Australia
| | - Martin Westbrooke
- School of Environmental Science Federation University Ballarat Victoria 3350 Australia
| | - Mike Wouters
- Fire & Flood Management, Department for Environment and Water Adelaide South Australia 5000 Australia
| | - Matthew White
- School of Ecosystem and Forest Sciences The University of Melbourne Parkville Victoria 3010 Australia
| | - Andrew F. Bennett
- Department of Ecology, Environment and Evolution, School of Life Sciences La Trobe University Bundoora Victoria 3086 Australia
- Research Centre for Future Landscapes, La Trobe University Bundoora Victoria 3086 Australia
- Victorian Department of Environment, Land Water & Planning Arthur Rylah Institute for Environmental Research 123 Brown St, Heidelberg Victoria 3081 Australia
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16
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Geiser F, Stawski C, Doty AC, Cooper CE, Nowack J. A burning question: what are the risks and benefits of mammalian torpor during and after fires? CONSERVATION PHYSIOLOGY 2018; 6:coy057. [PMID: 30323932 PMCID: PMC6181253 DOI: 10.1093/conphys/coy057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/11/2018] [Accepted: 10/08/2018] [Indexed: 06/08/2023]
Abstract
Although wildfires are increasing globally, available information on how mammals respond behaviourally and physiologically to fires is scant. Despite a large number of ecological studies, often examining animal diversity and abundance before and after fires, the reasons as to why some species perform better than others remain obscure. We examine how especially small mammals, which generally have high rates of energy expenditure and food requirements, deal with fires and post-fire conditions. We evaluate whether mammalian torpor, characterised by substantial reductions in body temperature, metabolic rate and water loss, plays a functional role in survival of mammals impacted by fires. Importantly, torpor permits small mammals to reduce their activity and foraging, and to survive on limited food. Torpid small mammals (marsupials and bats) can respond to smoke and arouse from torpor, which provides them with the possibility to evade direct exposure to fire, although their response is often slowed when ambient temperature is low. Post-fire conditions increase expression of torpor with a concomitant decrease in activity for free-ranging echidnas and small forest-dwelling marsupials, in response to reduced cover and reduced availability of terrestrial insects. Presence of charcoal and ash increases torpor use by captive small marsupials beyond food restriction alone, likely in anticipation of detrimental post-fire conditions. Interestingly, although volant bats use torpor on every day after fires, they respond by decreasing torpor duration, and increasing activity, perhaps because of the decrease in clutter and increase in foraging opportunities due to an increase in aerial insects. Our summary shows that torpor is an important tool for post-fire survival and, although the physiological and behavioural responses of small mammals to fire are complex, they seem to reflect energetic requirements and mode of foraging. We make recommendations on the conditions during management burns that are least likely to impact heterothermic mammals.
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Affiliation(s)
- Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
| | - Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Anna C Doty
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, USA
| | - Christine E Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia
| | - Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
- School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool, UK
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17
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Chmura HE, Glass TW, Williams CT. Biologging Physiological and Ecological Responses to Climatic Variation: New Tools for the Climate Change Era. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00092] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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18
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Nowack J, Stawski C, Körtner G, Geiser F. Physiological and behavioral responses of an arboreal mammal to smoke and charcoal-ash substrate. Physiol Behav 2018; 184:116-121. [DOI: 10.1016/j.physbeh.2017.11.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/08/2017] [Accepted: 11/16/2017] [Indexed: 10/18/2022]
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19
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Geiser F, Stawski C, Wacker CB, Nowack J. Phoenix from the Ashes: Fire, Torpor, and the Evolution of Mammalian Endothermy. Front Physiol 2017; 8:842. [PMID: 29163191 PMCID: PMC5673639 DOI: 10.3389/fphys.2017.00842] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/09/2017] [Indexed: 12/02/2022] Open
Affiliation(s)
- Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
| | - Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
| | - Chris B Wacker
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia
| | - Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, Australia.,Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
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20
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Williams CT, Buck CL, Sheriff MJ, Richter MM, Krause JS, Barnes BM. Sex-Dependent Phenological Plasticity in an Arctic Hibernator. Am Nat 2017; 190:854-859. [PMID: 29166160 DOI: 10.1086/694320] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Hibernation provides a means of escaping the metabolic challenges associated with seasonality, yet the ability of mammals to prolong or reenter seasonal dormancy in response to extreme weather events is unclear. Here, we show that Arctic ground squirrels in northern Alaska exhibited sex-dependent plasticity in the physiology and phenology of hibernation in response to a series of late spring snowstorms in 2013 that resulted in the latest snowmelt on record. Females and nonreproductive males responded to the >1-month delay in snowmelt by extending heterothermy or reentering hibernation after several days of euthermy, leading to a >2-week delay in reproduction compared to surrounding years. In contrast, reproductive males neither extended nor reentered hibernation, likely because seasonal gonadal growth and development and subsequent testosterone release prevents a return to torpor. Our findings reveal intriguing differences in responses of males and females to climatic stressors, which can generate a phenological mismatch between the sexes.
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21
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Welman S, Tuen AA, Lovegrove BG. Searching for the Haplorrhine Heterotherm: Field and Laboratory Data of Free-Ranging Tarsiers. Front Physiol 2017; 8:745. [PMID: 29018365 PMCID: PMC5623056 DOI: 10.3389/fphys.2017.00745] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 09/12/2017] [Indexed: 01/26/2023] Open
Abstract
The observation of heterothermy in a single suborder (Strepsirrhini) only within the primates is puzzling. Given that the placental-mammal ancestor was likely a heterotherm, we explored the potential for heterothermy in a primate closely related to the Strepsirrhini. Based upon phylogeny, body size and habitat stability since the Late Eocene, we selected western tarsiers (Cephalopachus bancanus) from the island of Borneo. Being the sister clade to Strepsirrhini and basal in Haplorrhini (monkeys and apes), we hypothesized that C. bancanus might have retained the heterothermic capacity observed in several small strepsirrhines. We measured resting metabolic rate, subcutaneous temperature, evaporative water loss and the percentage of heat dissipated through evaporation, at ambient temperatures between 22 and 35°C in fresh-caught wild animals (126.1 ± 2.4 g). We also measured core body temperatures in free-ranging animals. The thermoneutral zone was 25-30°C and the basal metabolic rate was 3.52 ± 0.06 W.kg-1 (0.65 ± 0.01 ml O2.g-1.h-1). There was no evidence of adaptive heterothermy in either the laboratory data or the free-ranging data. Instead, animals appeared to be cold sensitive (Tb ~ 31°C) at the lowest temperatures. We discuss possible reasons for the apparent lack of heterothermy in tarsiers, and identify putative heterotherms within Platyrrhini. We also document our concern for the vulnerability of C. bancanus to future temperature increases associated with global warming.
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Affiliation(s)
- Shaun Welman
- School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Andrew A. Tuen
- Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, Kota Samarahan, Malaysia
| | - Barry G. Lovegrove
- School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
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22
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Pettett CE, Johnson PJ, Moorhouse TP, Hambly C, Speakman JR, Macdonald DW. Daily energy expenditure in the face of predation: hedgehog energetics in rural landscapes. ACTA ACUST UNITED AC 2017; 220:460-468. [PMID: 28148819 DOI: 10.1242/jeb.150359] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 11/17/2016] [Indexed: 02/05/2023]
Abstract
Failure to balance daily energy expenditure (DEE) with energy intake can have an impact on survival and reproduction, and therefore on the persistence of populations. Here we study the DEE of the European hedgehog (Erinaceus europaeus), which is declining in the UK. We hypothesise that there is a gradient of suitable habitat for hedgehogs in rural areas, which is a result of fewer food resources, a higher risk from predation by badgers (Meles meles) and colder ambient temperatures, as distance to the nearest building increases. We used the doubly labelled water method to obtain 44 measurements of DEE from hedgehogs on four predominately arable sites, to determine the energetic costs associated with proximity to buildings, on sites with and without badgers. The mean±s.e.m. DEE was 508.9±34.8 kJ day-1 DEE increased the further a hedgehog was from buildings during the study, possibly as they ranged larger distances on arable land, supporting the hypothesis that hedgehogs select villages owing to the lower energy demands in comparison to arable farmland. Hedgehogs had an approximately 30% lower DEE on sites with badgers. We speculate that on badger-occupied sites, hedgehogs may restrict movement and foraging in response to a threat from predation and thus have reduced DEE. Therefore, hedgehogs may also seek refuge in villages where the perceived threat of predation is lower and foraging is unrestricted. In a broader context, we demonstrate that individual differences in DEE can aid in understanding habitat selection in a patchily distributed species.
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Affiliation(s)
- Carly E Pettett
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Oxfordshire OX13 5QL, UK
| | - Paul J Johnson
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Oxfordshire OX13 5QL, UK
| | - Tom P Moorhouse
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Oxfordshire OX13 5QL, UK
| | - Catherine Hambly
- Energetics Research Group, Zoology Department, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - John R Speakman
- Energetics Research Group, Zoology Department, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Oxfordshire OX13 5QL, UK
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23
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Stawski C, Hume T, Körtner G, Currie SE, Nowack J, Geiser F. Post-fire recovery of torpor and activity patterns of a small mammal. Biol Lett 2017; 13:rsbl.2017.0036. [PMID: 28515330 DOI: 10.1098/rsbl.2017.0036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/25/2017] [Indexed: 11/12/2022] Open
Abstract
To cope with the post-fire challenges of decreased availability of food and shelter, brown antechinus (Antechinus stuartii), a small marsupial mammal, increase the use of energy-conserving torpor and reduce activity. However, it is not known how long it takes for animals to resume pre-fire torpor and activity patterns during the recovery of burnt habitat. Therefore, we tested the hypothesis that antechinus will adjust torpor use and activity after a fire depending on vegetation recovery. We simultaneously quantified torpor and activity patterns for female antechinus from three adjacent areas: (i) the area of a management burn 1 year post-fire, (ii) an area that was burned 2 years prior, and (iii) a control area. In comparison to shortly after the management burn, antechinus in all three groups displayed less frequent and less pronounced torpor while being more active. We provide the first evidence that only 1 year post-fire antechinus resume pre-fire torpor and activity patterns, probably in response to the return of herbaceous ground cover and foraging opportunities.
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Affiliation(s)
- Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia
| | - Taylor Hume
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia
| | - Gerhard Körtner
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia
| | - Shannon E Currie
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia.,Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia.,Research Institute of Wildlife Ecology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna, Savoyenstrasse 1, 1160 Vienna, Austria
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale 2351, New South Wales, Australia
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24
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More functions of torpor and their roles in a changing world. J Comp Physiol B 2017; 187:889-897. [PMID: 28432393 PMCID: PMC5486538 DOI: 10.1007/s00360-017-1100-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/26/2016] [Accepted: 02/26/2017] [Indexed: 02/06/2023]
Abstract
Increased winter survival by reducing energy expenditure in adult animals is often viewed as the primary function of torpor. However, torpor has many other functions that ultimately increase the survival of heterothermic mammals and birds. In this review, we summarize new findings revealing that animals use torpor to cope with the conditions during and after natural disasters, including fires, storms, and heat waves. Furthermore, we suggest that torpor, which also prolongs longevity and was likely crucial for survival of mammals during the time of the dinosaur extinctions, will be advantageous in a changing world. Climate change is assumed to lead to an increase in the occurrence and intensity of climatic disasters, such as those listed above and also abnormal floods, droughts, and extreme temperatures. The opportunistic use of torpor, found in many heterothermic species, will likely enhance survival of these challenges, because these species can reduce energy and foraging requirements. However, many strictly seasonal hibernators will likely face the negative consequences of the predicted increase in temperature, such as range contraction. Overall, available data suggest that opportunistic heterotherms with their flexible energy requirements have an adaptive advantage over homeotherms in response to unpredictable conditions.
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25
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Abstract
In 1803, the French anatomist Étienne Geoffroy Saint-Hilaire decided that the newly described echidna and platypus should be placed in a separate order, the monotremes, intermediate between reptiles and mammals. The first physiological observations showed monotremes had low body temperatures and metabolic rates, and the consensus was that they were at a stage of physiological development intermediate between "higher mammals" and "lower vertebrates." Subsequent studies demonstrated that platypuses and echidnas are capable of close thermoregulation in the cold although less so under hot conditions. Because the short-beaked echidna Tachyglossus aculeatus, may show very large daily variations in body temperature, as well as seasonal hibernation, it has been suggested that it may provide a useful model of protoendotherm physiology. Such analysis is complicated by the very significant differences in thermal relations between echidnas from different climates. In all areas female echidnas regulate Tb within 1°C during egg incubation. The lactation period is considered to be the most energetically expensive time for most female mammals but lactating echidnas showed no measurable difference in field metabolic rate from non-lactating females, while the lactation period is more than 200 days for Kangaroo Island echidnas but only 150 days in Tasmania. In areas with mild winters echidnas show reduced activity and shallow torpor in autumn and early winter, but in areas with cold winters echidnas enter true hibernation with Tb falling as low as 4.5°C. Monotremes do not possess brown adipose tissue and maximum rates of rewarming from hibernation in echidnas were only half those of marmots of the same mass. Although echidnas show very large seasonal variations in fat stores associated with hibernation there is no relationship between plasma leptin and adiposity. Leptin levels are lowest during post-reproductive fattening, supporting suggestions that in evolutionary terms the anorectic effects of leptin preceded the adiposity signal. BMR of platypuses is twice that of echidnas although maximum metabolism is similar. High levels of thyroid hormones in platypuses may be driving metabolism limited by low body temperature. Monotremes show a mosaic of plesiomorphic and derived features but can still inform our understanding of the evolution of endothermy.
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Affiliation(s)
- Stewart C. Nicol
- Biological Sciences, University of TasmaniaHobart, TAS, Australia
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26
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He T, Lamont BB. Baptism by fire: the pivotal role of ancient conflagrations in evolution of the Earth's flora. Natl Sci Rev 2017. [DOI: 10.1093/nsr/nwx041] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Fire became a defining feature of the Earth's processes as soon as land plants evolved 420 million years ago and has played a major role in shaping the composition and physiognomy of many ecosystems ever since. However, there remains a general lack of appreciation of the place of fire in the origin, evolution, ecology and conservation of the Earth's biodiversity. We review the literature on the presence of fire throughout the Earth's history following the evolution of land plants and examine the evidence for the origin and evolution of adaptive functional traits, biomes and major plant groups in relation to fire. We show that: (1) fire activities have fluctuated throughout geological time due to variations in climate, and more importantly in atmospheric oxygen, as these affected fuel levels and flammability; (2) fire promoted the early evolution and spread of major terrestrial plant groups; (3) fire has shaped the floristics, structure and function of major global biomes; and (4) fire has initiated and maintained the evolution of a wide array of fire-adapted functional traits since the evolution of land plants. We conclude that fire has been a fundamental agent of natural selection on terrestrial plants throughout the history of life on the Earth's land surface. We suggest that a paradigm shift is required to reassess ecological and evolutionary theories that exclude a role for fire, and also there is a need to review fire-suppression policies on ecosystem management and biodiversity conservation in global fire-prone regions.
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Affiliation(s)
- Tianhua He
- Department of Environment and Agriculture, Curtin University, Perth, WA 6845, Australia
| | - Byron B Lamont
- Department of Environment and Agriculture, Curtin University, Perth, WA 6845, Australia
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27
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Stawski C, Nowack J, Körtner G, Geiser F. A new cue for torpor induction: charcoal, ash and smoke. J Exp Biol 2017; 220:220-226. [DOI: 10.1242/jeb.146548] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/20/2016] [Indexed: 12/13/2022]
Abstract
ABSTRACT
Recent work has shown that the use of torpor for energy conservation increases after forest fires in heterothermic mammals, probably in response to the reduction of food. However, the specific environmental cues for this increased torpor expression remain unknown. It is possible that smoke and the novel substrate of charcoal and ash act as signals for an impending period of starvation requiring torpor. We therefore tested the hypothesis that the combined cues of smoke, a charcoal/ash substrate and food shortage will enhance torpor expression in a small forest-dwelling marsupial, the yellow-footed antechinus (Antechinus flavipes), because like other animals that live in fire-prone habitats they must effectively respond to fires to ensure survival. Activity and body temperature patterns of individuals in outdoor aviaries were measured under natural environmental conditions. All individuals were strictly nocturnal, but diurnal activity was observed shortly after smoke exposure. Overall, torpor in females was longer and deeper than that in males. Interestingly, while both males and females increased daily torpor duration during food restriction by >2-fold as anticipated, a combination of food restriction and smoke exposure on a charcoal/ash substrate further increased daily torpor duration by ∼2-fold in both sexes. These data show that this combination of cues for torpor induction is stronger than food shortage on its own. Our study provides significant new information on how a small forest-dwelling mammal responds to fire cues during and immediately after a fire and identifies a new, not previously recognised, regulatory mechanism for thermal biology in mammals.
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Affiliation(s)
- Clare Stawski
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
- Research Institute of Wildlife Ecology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna, Savoyenstrasse 1, Vienna 1160, Austria
| | - Gerhard Körtner
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
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28
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Matthews JK, Stawski C, Körtner G, Parker CA, Geiser F. Torpor and basking after a severe wildfire: mammalian survival strategies in a scorched landscape. J Comp Physiol B 2016; 187:385-393. [DOI: 10.1007/s00360-016-1039-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 09/14/2016] [Accepted: 09/30/2016] [Indexed: 11/24/2022]
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29
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Levesque DL, Nowack J, Stawski C. Modelling mammalian energetics: the heterothermy problem. ACTA ACUST UNITED AC 2016. [DOI: 10.1186/s40665-016-0022-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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30
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Nowack J, Delesalle M, Stawski C, Geiser F. Can hibernators sense and evade fires? Olfactory acuity and locomotor performance during deep torpor. Naturwissenschaften 2016; 103:73. [DOI: 10.1007/s00114-016-1396-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/27/2016] [Accepted: 07/29/2016] [Indexed: 10/21/2022]
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31
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Post-wildfire physiological ecology of an Australian microbat. J Comp Physiol B 2016; 186:937-46. [PMID: 27245066 DOI: 10.1007/s00360-016-1003-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/05/2016] [Accepted: 05/17/2016] [Indexed: 10/21/2022]
Abstract
Historical patterns of wildfires are being altered as a result of changing climate and therefore are becoming an increasingly pressing global issue. How small mammals deal physiologically with changes in landscape and food availability due to fire remains largely unknown, although recent studies on small heterothermic terrestrial mammals have shown an increase in post-fire torpor use to reduce energy and foraging requirements. However, data on the behavioural and physiological responses of bats after fires are scarce, although potentially these volant species may differ from terrestrial mammals. Therefore, we investigated the post-fire thermal biology and activity of lesser long-eared bats (Nyctophilus geoffroyi) using temperature-telemetry in Warrumbungle National Park, NSW, which experienced a devastating wildfire in 2013. The study comprised two field seasons, one in 2013 within 4 months after the fire, and one in 2015 two years after the fire to identify potential changes in behaviour and physiology. Interestingly, soon after the fire, bats showed significantly shorter torpor bout duration (11.8 ± 12.5 h) and longer normothermia duration (8.7 ± 4.6 h) in comparison to those in 2015 (torpor bout duration: 24.1 ± 23.5 h; normothermia duration: 2.5 ± 1.5 h). Insect availability was significantly (20-fold) higher in 2013 than in 2015, which was likely an important factor resulting in the short average torpor bout duration by N. geoffroyi after the fire. Our data indicate that volant bats appear to show the opposite post-fire behavioural and physiological responses to small terrestrial mammals, showing longer normothermic and active periods and shorter torpor bouts to capitalise on an increase in available post-fire resources.
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