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Mark-oliver Rödel - One of the best experts on this subject based on the ideXlab platform.
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The effect of geographic range and climate on Extinction Risk in the deep-time amphibian fossil record
Palaeogeography Palaeoclimatology Palaeoecology, 2020Co-Authors: Melanie Tietje, Mark-oliver Rödel, Martin SchobbenAbstract:Abstract Geographic range is of crucial importance concerning the Extinction Risk of species. However, our understanding of how the influence of this trait on Extinction Risk has varied through Earth history and across different climate regimes is still rather unexplored. This is especially true for taxa that are currently of strong interest in conservation biology, displaying a strong mismatch between paleontological studies and modern efforts to quantify the Extinction Risk of threatened species. We herein calculated a continuous measure for the connection of geographic range and Extinction Risk in the deep-time amphibian fossil record. Furthermore, we evaluated the impact of climate on this connection, using two climate proxies derived from oxygen isotope data (global relative temperature change and variations in the latitudinal temperature gradient). We show that geographic ranges tended to be larger during times of comparatively small latitudinal temperature gradients. Moreover, the strength of geographic range influencing Extinction Risk fluctuated temporally, but remained positive at all times. The variation in range size impact on Extinction Risk showed a strong connection with the latitudinal temperature gradient. Our findings indicate that geographic range persists as a factor influencing species’ Extinction Risk through all times. However, geographic range seemed less important during times of higher environmental variability. Reasons might be the restriction of species ranges due to environmental constraints, causing ranges to become more similar and therefore lose relative importance in buffering for Extinction Risk, while other factors gain in importance. Simultaneously, similar ranges might be more prone to alteration by e.g. conservation biases (related to sedimentary deposition and fossilization) in relation to their real range size, resulting in a smaller signal-to-noise ratio, potentially affecting the correlation strength. We show that trait-Extinction Risk dynamics can vary in their intensity, and that specifically the observed impact of geographic range on Extinction Risk can vary with climatic changes.
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Evaluating the predicted Extinction Risk of living amphibian species with the fossil record.
Ecology letters, 2018Co-Authors: Melanie Tietje, Mark-oliver RödelAbstract:Bridging the gap between the fossil record and conservation biology has recently become of great interest. The enormous number of documented Extinctions across different taxa can provide insights into the Extinction Risk of living species. However, few studies have explored this connection. We used generalised boosted modelling to analyse the impact of several traits that are assumed to influence Extinction Risk on the stratigraphic duration of amphibian species in the fossil record. We used this fossil-calibrated model to predict the Extinction Risk for living species. We observed a high consensus between our predicted species durations and the current IUCN Red List status of living amphibian species. We also found that today's Data Deficient species are mainly predicted to experience short durations, hinting at their likely high threat status. Our study suggests that the fossil record can be a suitable tool for the evaluation of current taxa-specific Red Listing status.
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Contradicting habitat type-Extinction Risk relationships between living and fossil amphibians
Royal Society open science, 2017Co-Authors: Melanie Tietje, Mark-oliver RödelAbstract:Trait analysis has become a crucial tool for assessing the Extinction Risk of species. While some Extinction Risk-trait relationships have been often identical between different living taxa, a temp...
Melanie Tietje - One of the best experts on this subject based on the ideXlab platform.
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The effect of geographic range and climate on Extinction Risk in the deep-time amphibian fossil record
Palaeogeography Palaeoclimatology Palaeoecology, 2020Co-Authors: Melanie Tietje, Mark-oliver Rödel, Martin SchobbenAbstract:Abstract Geographic range is of crucial importance concerning the Extinction Risk of species. However, our understanding of how the influence of this trait on Extinction Risk has varied through Earth history and across different climate regimes is still rather unexplored. This is especially true for taxa that are currently of strong interest in conservation biology, displaying a strong mismatch between paleontological studies and modern efforts to quantify the Extinction Risk of threatened species. We herein calculated a continuous measure for the connection of geographic range and Extinction Risk in the deep-time amphibian fossil record. Furthermore, we evaluated the impact of climate on this connection, using two climate proxies derived from oxygen isotope data (global relative temperature change and variations in the latitudinal temperature gradient). We show that geographic ranges tended to be larger during times of comparatively small latitudinal temperature gradients. Moreover, the strength of geographic range influencing Extinction Risk fluctuated temporally, but remained positive at all times. The variation in range size impact on Extinction Risk showed a strong connection with the latitudinal temperature gradient. Our findings indicate that geographic range persists as a factor influencing species’ Extinction Risk through all times. However, geographic range seemed less important during times of higher environmental variability. Reasons might be the restriction of species ranges due to environmental constraints, causing ranges to become more similar and therefore lose relative importance in buffering for Extinction Risk, while other factors gain in importance. Simultaneously, similar ranges might be more prone to alteration by e.g. conservation biases (related to sedimentary deposition and fossilization) in relation to their real range size, resulting in a smaller signal-to-noise ratio, potentially affecting the correlation strength. We show that trait-Extinction Risk dynamics can vary in their intensity, and that specifically the observed impact of geographic range on Extinction Risk can vary with climatic changes.
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Evaluating the predicted Extinction Risk of living amphibian species with the fossil record.
Ecology letters, 2018Co-Authors: Melanie Tietje, Mark-oliver RödelAbstract:Bridging the gap between the fossil record and conservation biology has recently become of great interest. The enormous number of documented Extinctions across different taxa can provide insights into the Extinction Risk of living species. However, few studies have explored this connection. We used generalised boosted modelling to analyse the impact of several traits that are assumed to influence Extinction Risk on the stratigraphic duration of amphibian species in the fossil record. We used this fossil-calibrated model to predict the Extinction Risk for living species. We observed a high consensus between our predicted species durations and the current IUCN Red List status of living amphibian species. We also found that today's Data Deficient species are mainly predicted to experience short durations, hinting at their likely high threat status. Our study suggests that the fossil record can be a suitable tool for the evaluation of current taxa-specific Red Listing status.
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Contradicting habitat type-Extinction Risk relationships between living and fossil amphibians
Royal Society open science, 2017Co-Authors: Melanie Tietje, Mark-oliver RödelAbstract:Trait analysis has become a crucial tool for assessing the Extinction Risk of species. While some Extinction Risk-trait relationships have been often identical between different living taxa, a temp...
Nicholas K. Dulvy - One of the best experts on this subject based on the ideXlab platform.
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Rethinking Trade-Driven Extinction Risk in Marine and Terrestrial Megafauna
Current biology : CB, 2016Co-Authors: Loren Mcclenachan, Andrew B. Cooper, Nicholas K. DulvyAbstract:Summary Large animals hunted for the high value of their parts (e.g., elephant ivory and shark fins) are at Risk of Extinction due to both intensive international trade pressure and intrinsic biological sensitivity. However, the relative role of trade, particularly in non-perishable products, and biological factors in driving Extinction Risk is not well understood [1–4]. Here we identify a taxonomically diverse group of >100 marine and terrestrial megafauna targeted for international luxury markets; estimate their value across three points of sale; test relationships among Extinction Risk, high value, and body size; and quantify the effects of two mitigating factors: poaching fines and geographic range size. We find that body size is the principal driver of Risk for lower value species, but that this biological pattern is eliminated above a value threshold, meaning that the most valuable species face a high Extinction Risk regardless of size. For example, once mean product values exceed US$12,557 kg −1 , body size no longer drives Risk. Total value scales with size for marine animals more strongly than for terrestrial animals, incentivizing the hunting of large marine individuals and species. Poaching fines currently have little effect on Extinction Risk; fines would need to be increased 10- to 100-fold to be effective. Large geographic ranges reduce Risk for terrestrial, but not marine, species, whose ranges are ten times greater. Our results underscore both the evolutionary and ecosystem consequences of targeting large marine animals and the need to geographically scale up and prioritize conservation of high-value marine species to avoid Extinction.
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Extinction Risk and bottlenecks in the conservation of charismatic marine species
Conservation Letters, 2012Co-Authors: Loren Mcclenachan, Andrew B. Cooper, Kent Carpenter, Nicholas K. DulvyAbstract:The oceans face a biodiversity crisis, but the degree and scale of Extinction Risk remains poorly characterized. Charismatic species are most likely to garner greatest support for conservation and thus provide a best-case scenario of the status of marine biodiversity. We summarize Extinction Risk and diagnose impediments to successful conservation for 1,568 species in 16 families of marine animals in the movie Finding Nemo. Sixteen percent (12–34%) of those that have been evaluated are threatened, ranging from 9% (7–28%) of bony fishes to 100% (83–100%) of marine turtles. A lack of scientific knowledge impedes analysis of threat status for invertebrates, which have 1,000 times fewer conservation papers than do turtles. Legal protection is severely deficient for sharks and rays; only 8% of threatened species in our analysis are protected. Extinction Risk among wide-ranging taxa is higher than most terrestrial groups, suggesting a different conservation focus is required in the sea.
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Methods of assessing Extinction Risk in marine fishes.
Fish and Fisheries, 2004Co-Authors: Nicholas K. Dulvy, Jim R. Ellis, Nicholas B. Goodwin, Alastair Grant, John D. Reynolds, Simon JenningsAbstract:The decline and disappearance of species from large parts of their former geographical range has become an important issue in fisheries ecology. There is a need to identify which species are at Risk of Extinction. The available approaches have been subject to considerable debate – particularly when applied to commercially exploited species. Here we have compiled methods that have been used or may be used for assessing threat status of marine organisms. We organize the methods according to the availability of data on the natural history, ecology and population biology of species. There are three general approaches to inferring or assessing Extinction Risk: (i) correlative approaches based on knowledge of life histories and ecology; (ii) time-series approaches that examine changes in abundance; and (iii) demographic approaches based on age- or stage-based schedules of vital rates and fisheries reference points. Many methods are well suited to species that are highly catchable and/or have relatively low productivity, but theory is less well developed for assessing Extinction Risk in species exhibiting narrow geographical distributions or ecological specialization. There is considerable variation in both definitions of Extinction Risk and the precision and defensibility of the available Risk assessment methods, so we suggest a two-tiered approach for defining and assessing Extinction Risk. First, simple methods requiring a few easily estimated parameters are used to triage or rapidly assess large numbers of populations and species to identify potentially vulnerable populations or species. Second, the populations and species identified as vulnerable by this process can then be subject to more detailed and rigorous population analysis explicitly considering sources of error and uncertainty.
Alan Hastings - One of the best experts on this subject based on the ideXlab platform.
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Extinction Risk depends strongly on factors contributing to stochasticity
Nature, 2008Co-Authors: Brett A Melbourne, Alan HastingsAbstract:The Risk that a natural population can become extinct is a fundamental biological process, and is central to our understanding of biodiversity and evolution. But Brett Melbourne and Alan Hastings contend that existing mathematical models of Extinction Risk ascribe variability in population numbers to the wrong processes. In work that combines a new mathematical theory with experimental data, they show that different kinds of random-ness in the life of an animal combine in such a way that the Risk of Extinction is many times higher than previously thought possible, and that estimated Risks of Extinction for endangered species need to be raised. Extinction is a fundamental process in biological systems, and is central to our understanding of biodiversity and evolution. The use of mathematics linked to experiments on insect populations shows that different kinds of randomness in the life of an animal combine together in such a way that the Risk of Extinction is many times higher than previously thought possible. Extinction Risk in natural populations depends on stochastic factors that affect individuals, and is estimated by incorporating such factors into stochastic models1,2,3,4,5,6,7,8,9. Stochasticity can be divided into four categories, which include the probabilistic nature of birth and death at the level of individuals (demographic stochasticity2), variation in population-level birth and death rates among times or locations (environmental stochasticity1,3), the sex of individuals6,8 and variation in vital rates among individuals within a population (demographic heterogeneity7,9). Mechanistic stochastic models that include all of these factors have not previously been developed to examine their combined effects on Extinction Risk. Here we derive a family of stochastic Ricker models using different combinations of all these stochastic factors, and show that Extinction Risk depends strongly on the combination of factors that contribute to stochasticity. Furthermore, we show that only with the full stochastic model can the relative importance of environmental and demographic variability, and therefore Extinction Risk, be correctly determined. Using the full model, we find that demographic sources of stochasticity are the prominent cause of variability in a laboratory population of Tribolium castaneum (red flour beetle), whereas using only the standard simpler models would lead to the erroneous conclusion that environmental variability dominates. Our results demonstrate that current estimates of Extinction Risk for natural populations could be greatly underestimated because variability has been mistakenly attributed to the environment rather than the demographic factors described here that entail much higher Extinction Risk for the same variability level.
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Extinction Risk depends strongly on factors contributing to stochasticity
Nature, 2008Co-Authors: Brett A Melbourne, Alan HastingsAbstract:Extinction Risk in natural populations depends on stochastic factors that affect individuals, and is estimated by incorporating such factors into stochastic models. Stochasticity can be divided into four categories, which include the probabilistic nature of birth and death at the level of individuals (demographic stochasticity), variation in population-level birth and death rates among times or locations (environmental stochasticity), the sex of individuals and variation in vital rates among individuals within a population (demographic heterogeneity). Mechanistic stochastic models that include all of these factors have not previously been developed to examine their combined effects on Extinction Risk. Here we derive a family of stochastic Ricker models using different combinations of all these stochastic factors, and show that Extinction Risk depends strongly on the combination of factors that contribute to stochasticity. Furthermore, we show that only with the full stochastic model can the relative importance of environmental and demographic variability, and therefore Extinction Risk, be correctly determined. Using the full model, we find that demographic sources of stochasticity are the prominent cause of variability in a laboratory population of Tribolium castaneum (red flour beetle), whereas using only the standard simpler models would lead to the erroneous conclusion that environmental variability dominates. Our results demonstrate that current estimates of Extinction Risk for natural populations could be greatly underestimated because variability has been mistakenly attributed to the environment rather than the demographic factors described here that entail much higher Extinction Risk for the same variability level.
Marcel Cardillo - One of the best experts on this subject based on the ideXlab platform.
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Spatial, Phylogenetic, Environmental and Biological Components of Variation in Extinction Risk: A Case Study Using Banksia.
PloS one, 2016Co-Authors: Marcel Cardillo, Alexander SkeelsAbstract:Comparative analyses of Extinction Risk routinely apply methods that account for phylogenetic non-independence, but few analyses of Extinction Risk have addressed the possibility of spatial non-independence. We explored patterns of Extinction Risk in Banksia, a plant genus largely endemic to Australia’s southwest biodiversity hotspot, using methods to partition the variance in two response variables (threat status and range size) into phylogenetic, spatial, and independent components. We then estimated the effects of a number of biological and external predictors on Extinction Risk independently of phylogeny and space. The models explained up to 34.2% of the variation in range size and up to 9.7% of the variation in threat status, nearly all of which was accounted for by the predictors, not by phylogeny or space. In the case of Banksia, therefore, high Extinction Risk can be clearly linked with biological syndromes (such as a brief flowering period) or geographic indicators of human impact (such as extensive habitat loss), but cannot be predicted from phylogenetic relatedness or geographic proximity.
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Clarifying the relationship between torpor and anthropogenic Extinction Risk in mammals
Journal of Zoology, 2014Co-Authors: Emily Hanna, Marcel CardilloAbstract:The ability to undertake torpor has been linked with human-mediated Extinction Risk in mammals, but whether torpor serves to elevate or decrease Extinction Risk, and the mechanism by which it does so, remain controversial. We attempt to clarify the torpor – Extinction Risk association in a phylogenetic comparative analysis of 284 Australian mammal species. We show that the association is strongly mediated by body size. When body mass is included as a covariate, regression models show a negative association between the ability to undertake torpor and current threat status. This association is present in two categories of mammal species likely to be at particular Risk from introduced predators (medium-sized species and species listed as threatened by predation in the International Union for Conservation of Nature Red List), but there is no association among species not in these categories. This suggests that torpor reduces vulnerability to predators, perhaps by limiting the amount of time spent foraging. However, the association between torpor and Extinction Risk is also stronger in smaller species, which are more likely to benefit from a reduced energy budget in Australia’s low-productivity and unpredictable environment. We conclude that the ability to undertake torpor is clearly an advantage to mammal species in coping with human impacts, and that this advantage is conferred through a combination of reduced exposure to predators and reduced energy requirements.
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A novel approach for global mammal Extinction Risk reduction
Conservation Letters, 2012Co-Authors: Moreno Di Marco, Hugh P. Possingham, Luigi Boitani, Marcel Cardillo, Kerrie A. Wilson, Simon P. Blomberg, Carlo RondininiAbstract:With one-fourth of the world's mammals threatened with Extinction and limited budget to save them, adopting an efficient conservation strategy is crucial. Previous approaches to setting global conservation priorities have assumed all species to have equal conservation value, or have focused on species with high Extinction Risk, species that may be hard to save. Here, we identify priority species for optimizing the reduction in overall Extinction Risk of the world's threatened terrestrial mammals. We take a novel approach and focus on species having the greatest recovery opportunity using a new conservation benefit metric: the Extinction Risk Reduction Opportunity (ERO). We discover that 65-87 of all threatened and potentially recoverable species are overlooked by existing prioritization approaches. We use the ERO metric to prioritize threatened species, but the potential applications are broader; ERO has the potential to integrate with every strategy that aims to maximize the likelihood of conservation success. © 2012 Wiley Periodicals, Inc.
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human population density and Extinction Risk in the world s carnivores
PLOS Biology, 2004Co-Authors: Andy Purvis, John L. Gittleman, Jon Bielby, Marcel Cardillo, Wes Sechrest, Georgina M MaceAbstract:Understanding why some species are at high Risk of Extinction, while others remain relatively safe, is central to the development of a predictive conservation science. Recent studies have shown that a species' Extinction Risk may be determined by two types of factors: intrinsic biological traits and exposure to external anthropogenic threats. However, little is known about the relative and interacting effects of intrinsic and external variables on Extinction Risk. Using phylogenetic comparative methods, we show that Extinction Risk in the mammal order Carnivora is predicted more strongly by biology than exposure to high-density human populations. However, biology interacts with human population density to determine Extinction Risk: biological traits explain 80% of variation in Risk for carnivore species with high levels of exposure to human populations, compared to 45% for carnivores generally. The results suggest that biology will become a more critical determinant of Risk as human populations expand. We demonstrate how a model predicting Extinction Risk from biology can be combined with projected human population density to identify species likely to move most rapidly towards Extinction by the year 2030. African viverrid species are particularly likely to become threatened, even though most are currently considered relatively safe. We suggest that a preemptive approach to species conservation is needed to identify and protect species that may not be threatened at present but may become so in the near future.
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Biological determinants of Extinction Risk: why are smaller species less vulnerable?
Animal Conservation, 2003Co-Authors: Marcel CardilloAbstract:It is becoming increasingly clear that species of smaller body size tend to be less vulnerable to contemporary Extinction threats than larger species, but few studies have examined the mechanisms underlying this pattern. In this paper, data for the Australian terrestrial mammal fauna are used to ask whether higher reproductive output or smaller home ranges can explain the reduced Extinction Risk of smaller species. Extinct and endangered species do indeed have smaller litters and larger home ranges for their body size than expected under a null model. In multiple regressions, however, only litter size is a significant predictor of Extinction Risk once body size and phylogeny are controlled for. Larger litters contribute to fast population growth, and are probably part of the reason that smaller species are less Extinction-prone. The effect of litter size varies between the mesic coastal regions and the arid interior of Australia, indicating that the environment a species inhabits mediates the effect of biology on Extinction Risk. These results suggest that predicting Extinction Risk from biological traits is likely to be a complex task which must consider explicitly interactions between biology and environment.
