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Staufer M, Burgstaller S, Horvath A, Landler L. Temporal and spatial variations in local sex ratios in a suburban population of the European green toad Bufotes viridis. BMC Ecol Evol 2023; 23:6. [PMID: 36932330 PMCID: PMC10024452 DOI: 10.1186/s12862-023-02106-0] [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: 04/03/2022] [Accepted: 02/23/2023] [Indexed: 03/19/2023] Open
Abstract
BACKGROUND Sex ratios of animal populations are important factors of population demographics. In pond-breeding amphibians, the operational sex ratio (OSR) among the breeding population is usually male-biased. Also, in European green toads (Bufotes viridis), males usually outnumber females at breeding sites, while the sex ratio of the total adult population (ASR) is assumed to be balanced. It has been suggested that sex-specific breeding behavior causes male-predominance at the breeding sites. We used a dataset of 5 years of street patrols to test this hypothesis. For this we analyzed local sex ratios of green toads in terrestrial habitats and at two artificial breeding ponds. We expected temporal and/or spatial changes of local sex ratios which would indicate sex dependent differences in breeding behavior. RESULTS Overall observed ASR among 2111 green toads, counted in the course of street patrols from 2016 to 2020, was slightly male-biased (ASR = 0.56, annual ASRs = 0.49-0.63). Based on the data of 1631 toads (920 males, 711 females) captured within a radius of 300 m around nine main breeding sites, temporal and spatial variations in local ASRs were evaluated. Resulting values were compared to the calculated OSR at two artificial breeding ponds in 2021 (645 adult: 553 males, 92 females). Estimates predict more equally distributed females and males prior to the main breeding season. During breeding season, males predominated at both breeding sites (B1: 0.83, B2: 0.89), whereas females are estimated to outnumber males in terrestrial habitats. Proportions of females highly significantly increased with advancing time of the year and increasing distance to the breeding sites. While males tended to accumulate in proximity to water bodies, females dispersed soon after breeding to more distant areas. CONCLUSIONS Observed sex ratios in the studied green toad population changed with time and sampling site, deviating from the population-wide sex ratio. Expanding sampling effort in amphibian conservation assessments in time and space, i.e., outside the main breeding season and away from the breeding sites, would be important to encompass such variations.
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Affiliation(s)
| | - Stephan Burgstaller
- Institute of Zoology, Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Strasse 33, 1180, Vienna, Austria
| | - András Horvath
- Institute of Zoology, Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Strasse 33, 1180, Vienna, Austria
| | - Lukas Landler
- Institute of Zoology, Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Strasse 33, 1180, Vienna, Austria.
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Terrell VCK, Maerz JC, Engbrecht NJ, Stiles RM, Crawford BA, Lannoo MJ. Breeding Population Dynamics of Threatened Crawfish Frogs Inform Targets for Habitat Management. ICHTHYOLOGY & HERPETOLOGY 2023. [DOI: 10.1643/h2022031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
| | - John C. Maerz
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602
| | - Nathan J. Engbrecht
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Terre Haute, Indiana 47809
| | - Rochelle M. Stiles
- Department of Biology, Indiana State University, Terre Haute, Indiana 47809
| | - Brian A. Crawford
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602
| | - Michael J. Lannoo
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Terre Haute, Indiana 47809
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Crawford BA, Maerz JC, Terrell VC, Moore CT. Population viability analysis for a pond-breeding amphibian under future drought scenarios in the southeastern United States. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Barrile GM, Chalfoun AD, Estes‐Zumpf WA, Walters AW. Wildfire influences individual growth and breeding dispersal, but not survival and recruitment in a montane amphibian. Ecosphere 2022. [DOI: 10.1002/ecs2.4212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Gabriel M. Barrile
- Wyoming Cooperative Fish and Wildlife Research Unit, Program in Ecology, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | - Anna D. Chalfoun
- U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology and Program in Ecology University of Wyoming Laramie Wyoming USA
| | | | - Annika W. Walters
- U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology and Program in Ecology University of Wyoming Laramie Wyoming USA
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Zamora-Camacho FJ. The relationships between toad behaviour, antipredator defences, and spatial and sexual variation in predation pressure. PeerJ 2022; 10:e12985. [PMID: 35194533 PMCID: PMC8858576 DOI: 10.7717/peerj.12985] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/01/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Animal behaviour is under strong selection. Selection on behaviour, however, might not act in isolation from other fitness-related traits. Since predators represent outstanding selective forces, animal behaviour could covary with antipredator defences, such that individuals better suited against predators could afford facing the costs of riskier behaviours. Moreover, not all individuals undergo equivalent degrees of predation pressure, which can vary across sexes or habitats. Individuals under lower predation pressure might also exhibit riskier behaviours. METHODS In this work, I tested these hypotheses on natterjack toads (Epidalea calamita). Specifically, I gauged activity time, exploratory behaviour and boldness in standard laboratory conditions, and assessed whether they correlated with body size and antipredator strategies, namely sprint speed, parotoid gland area and parotoid gland colour contrast. Additionally, I compared these traits between sexes and individuals from an agrosystem and pine grove, since there is evidence that males and agrosystem individuals are subjected to greater predation pressure. RESULTS Sprint speed as well as parotoid gland contrast and size appeared unrelated to the behavioural traits studied. In turn, body mass was negatively related to activity time, boldness and exploration. This trend is consistent with the fact that larger toads could be more detectable to their predators, which are mostly gape unconstrained and could easily consume them. As predicted, females exhibited riskier behaviours. Nonetheless, agrosystem toads did not differ from pine grove toads in the behavioural traits measured, despite being under stronger predation pressure.
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Affiliation(s)
- Francisco Javier Zamora-Camacho
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Seville, Spain,Departamento de Biodiversidad, Ecología y Evolución, Universidad Complutense de Madrid, Madrid, Spain
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Thermal conditions predict intraspecific variation in senescence rate in frogs and toads. Proc Natl Acad Sci U S A 2021; 118:2112235118. [PMID: 34845023 DOI: 10.1073/pnas.2112235118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2021] [Indexed: 11/18/2022] Open
Abstract
Variation in temperature is known to influence mortality patterns in ectotherms. Even though a few experimental studies on model organisms have reported a positive relationship between temperature and actuarial senescence (i.e., the increase in mortality risk with age), how variation in climate influences the senescence rate across the range of a species is still poorly understood in free-ranging animals. We filled this knowledge gap by investigating the relationships linking senescence rate, adult lifespan, and climatic conditions using long-term capture-recapture data from multiple amphibian populations. We considered two pairs of related anuran species from the Ranidae (Rana luteiventris and Rana temporaria) and Bufonidae (Anaxyrus boreas and Bufo bufo) families, which diverged more than 100 Mya and are broadly distributed in North America and Europe. Senescence rates were positively associated with mean annual temperature in all species. In addition, lifespan was negatively correlated with mean annual temperature in all species except A. boreas In both R. luteiventris and A. boreas, mean annual precipitation and human environmental footprint both had negligible effects on senescence rates or lifespans. Overall, our findings demonstrate the critical influence of thermal conditions on mortality patterns across anuran species from temperate regions. In the current context of further global temperature increases predicted by Intergovernmental Panel on Climate Change scenarios, a widespread acceleration of aging in amphibians is expected to occur in the decades to come, which might threaten even more seriously the viability of populations and exacerbate global decline.
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A new method for the estimation of minimum adult frog density from a large-scale audial survey. Sci Rep 2020; 10:8627. [PMID: 32451461 PMCID: PMC7248064 DOI: 10.1038/s41598-020-65560-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 04/23/2020] [Indexed: 11/08/2022] Open
Abstract
Audial surveys of anuran amphibians (frogs, toads and similar) are cost-effective and allow for the coverage of large areas, but they are usually regarded as unsuitable for population size estimations due to imperfect detection. Our study demonstrated a method for obtaining minimum adult population size estimates from vocalising anuran counts by using sex ratios, life history and vocalising behaviour parameters from other studies. We collected data from 2016 to 2018 for seven taxa on 65 plots (each 25 km2) representing the entirety of Latvia. Among taxa, average breeding waterbody audible detection probabilities ranged from 0.56 to 0.88 per plot, minimum adult frog density (MAFD) estimates were from 12.0 to 51.7 individuals per km2, but the estimated fraction of population covered by MAFD varied from 57 to 86%. The least accurate density estimates were in taxa with brief calling activity and quiet mating calls (Rana temporaria), and in taxa with a calling activity dependent on the numbers of males in a pond (Bufo bufo). Our study suggests that lek-breeders would be more suitable than explosive-breeding taxa for minimum population size estimates from audial data. The use of MAFD allowed for coarse minimum population size estimates for the entire country from the audial monitoring data, these ranged from 3.7 ± 0.5 thousand (Bombina bombina) to 1.64 ± 0.47 million (B.bufo) adults.
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Muths E, Bailey LL, Lambert BA, Schneider SC. Estimating the probability of movement and partitioning seasonal survival in an amphibian metapopulation. Ecosphere 2018. [DOI: 10.1002/ecs2.2480] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Erin Muths
- U.S. Geological Survey Fort Collins Science Center 2150 Center Avenue, Building C Fort Collins Colorado 80526 USA
| | - Larissa L. Bailey
- Department of Fish, Wildlife, and Conservation Biology Colorado State University 1474 Campus Delivery Fort Collins Colorado 80523 USA
| | - Brad A. Lambert
- Colorado Natural Heritage Program Colorado State University Fort Collins Colorado 80523‐1475 USA
| | - Scott C. Schneider
- Colorado Natural Heritage Program Colorado State University Fort Collins Colorado 80523‐1475 USA
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Mazgajska J, Mazgajski TD. Low Recapture Rate in PIT Marked Urban Populations of the Common Toad. POLISH JOURNAL OF ECOLOGY 2016. [DOI: 10.3161/15052249pje2016.64.4.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Muths E, Scherer RD, Bosch J. Evidence for plasticity in the frequency of skipped breeding opportunities in common toads. POPUL ECOL 2013. [DOI: 10.1007/s10144-013-0381-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Willson JD, Winne CT, Todd BD. Ecological and methodological factors affecting detectability and population estimation in elusive species. J Wildl Manage 2011. [DOI: 10.1002/jwmg.15] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Olivier A, Barbraud C, Rosecchi E, Germain C, Cheylan M. Assessing spatial and temporal population dynamics of cryptic species: an example with the European pond turtle. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2010; 20:993-1004. [PMID: 20597285 DOI: 10.1890/09-0801.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Within the current context of biodiversity loss a number of biodiversity indicators have been developed to help measure the state of nature and how it is changing. However, most indicators are derived from bird populations. Reptiles and amphibians could be useful ecosystem indicators, but this requires obtaining precise and unbiased population parameters. This is a particularly challenging task for these two groups of species, because individuals are extremely difficult to detect for various reasons. We illustrate the use of a sampling and analytical method that explicitly takes into account imperfect detection to assess the population dynamics of a reptile species and its temporal and spatial variation. European pond turtles (Emys orbicularis) were sampled at two different locations during a 10-year study. The two sites differed by their water management regimes and number of livestock. At each site and for each sex, the data were modeled using a robust design capture-mark-recapture framework to obtain and compare estimates of survival, temporary emigration, time-specific abundance, density, and population growth rate, while taking into account effects of individual heterogeneity, trap-response, and time on capture probabilities. Temporary emigration was higher in males (0.344 +/- 0.046) (mean +/- SE) than in females (0.228 +/- 0.071), did not differ between sites for each sex, and was mainly Markovian. Apparent adult survival was higher in females (0.966 +/- 0.031) than in males (0.864 +/- 0.024), and was negatively related to the proportion of individuals with repaired shell fractures in the population. Average density was 63.7 +/- 6.6 turtles/km2 but was higher for females (39.2 +/- 14.0 females/km2) than for males (23.5 +/- 5.7 males/km2). The population sizes of males and females decreased where long periods of artificial drought and the highest density of livestock occurred. This research highlights differences in demographic parameters according to sex and site in a turtle species, and it provides evidence that significant human-induced disturbance represents a potential risk to European pond turtle populations. The sampling and analytical approaches illustrated in this study are applicable to many other species of reptiles and amphibians, and estimated population parameters could be combined to produce population indicators useful for conservation and management.
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Affiliation(s)
- Anthony Olivier
- Station Biologique de la Tour du Valat, Le Sambuc, 13200 Arles, France
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Muths E, Scherer RD, Lambert BA. Unbiased survival estimates and evidence for skipped breeding opportunities in females. Methods Ecol Evol 2010. [DOI: 10.1111/j.2041-210x.2010.00019.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Janin A, Léna JP, Ray N, Delacourt C, Allemand P, Joly P. Assessing landscape connectivity with calibrated cost-distance modelling: predicting common toad distribution in a context of spreading agriculture. J Appl Ecol 2009. [DOI: 10.1111/j.1365-2664.2009.01665.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Vasconcellos MM, Colli GR. Factors Affecting the Population Dynamics of Two Toads (Anura: Bufonidae) in a Seasonal Neotropical Savanna. COPEIA 2009. [DOI: 10.1643/ce-07-099] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Cvetković D, Tomašević N, Ficetola GF, Crnobrnja-Isailović J, Miaud C. Bergmann’s rule in amphibians: combining demographic and ecological parameters to explain body size variation among populations in the common toadBufo bufo. J ZOOL SYST EVOL RES 2009. [DOI: 10.1111/j.1439-0469.2008.00504.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Schmidt BR, Schaub M, Steinfartz S. Apparent survival of the salamander Salamandra salamandra is low because of high migratory activity. Front Zool 2007; 4:19. [PMID: 17803829 PMCID: PMC2020470 DOI: 10.1186/1742-9994-4-19] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 09/06/2007] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Understanding the demographic processes underlying population dynamics is a central theme in ecology. Populations decline if losses from the population (i.e., mortality and emigration) exceed gains (i.e., recruitment and immigration). Amphibians are thought to exhibit little movement even though local populations often fluctuate dramatically and are likely to go exinct if there is no rescue effect through immigration from nearby populations. Terrestrial salamanders are generally portrayed as amphibians with low migratory activity. Our study uses demographic analysis as a key to unravel whether emigration or mortality is the main cause of "losses" from the population. In particular, we use the analysis to challenge the common belief that terrestrial salamanders show low migratory activity. RESULTS The mark-recapture analysis of adult salamanders showed that monthly survival was high (> 90%) without a seasonal pattern. These estimates, however, translate into rather low rates of local annual survival of only ~40% and suggest that emigration was important. The estimated probability of emigration was 49%. CONCLUSION Our analysis shows that terrestrial salamanders exhibit more migratory activity than commonly thought. This may be due either because the spatial extent of salamander populations is underestimated or because there is a substantial exchange of individuals between populations. Our current results are in line with several other studies that suggest high migratory activity in amphibians. In particular, many amphibian populations may be characterized by high proportions of transients and/or floaters.
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Affiliation(s)
- Benedikt R Schmidt
- Zoologisches Institut, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- KARCH, Passage Maximilien-de-Meuron 6, 2000 Neuchâtel, Switzerland
| | - Michael Schaub
- Conservation Biology, Zoologisches Institut, Universität Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
- Schweizerische Vogelwarte, 6204 Sempach, Switzerland
| | - Sebastian Steinfartz
- University of Bielefeld, Department of Animal Behavior, Morgenbreede 45, 33615 Bielefeld, Germany
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BREDE EDWARDG, BEEBEE TREVORJC. Large variations in the ratio of effective breeding and census population sizes between two species of pond-breeding anurans. Biol J Linn Soc Lond 2006. [DOI: 10.1111/j.1095-8312.2006.00680.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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