Current Extinction Risk Research Articles

Red-list of Italian bryophytes. 2. Mosses

The paper provides the first comprehensive, region-wide assessment of mosses, evaluated according to IUCN’s Guidelines for Application of IUCN Red List Criteria at Regional Level. The IUCN Red List criteria were applied to 961 Italian moss taxa to assess their current extinction risk and to highlight the major threats affecting the Italian moss flora. Overall, 246 moss taxa assessed in this study are assigned to a risk category and, therefore, considered threatened in Italy, with a percentage of 28.6%. One species is considered Regionally Extinct and 15 species Possibly Extinct at regional level. A further 5.8% are categorized as Near Threatened, 10.6% as Data Deficient and 56.0% as Least Concern. Most threats are co-occurring, indicating that many taxa are subjected to a set of correlated adverse processes. The main IUCN major threats identified were Climate Change and Natural System Modifications (mostly dams and water management and use). Considering the overall Italian bryophyte flora, 330 taxa (246 mosses, 83 liverworts, and 1 hornwort) are considered threatened with extinction at Italian level (29.0% mid-point value), five species are classified as RE and 18 as CR(PE); moreover, 84 taxa are NT (6.6%) and 130 are considered as DD (10.3%).

Using genome-wide data to ascertain taxonomic status and assess population genetic structure for Houston toads (Bufo [= Anaxyrus] houstonensis)

The Houston toad (Bufo [= Anaxyrus] houstonensis) is an endangered amphibian with a small geographic range. Land-use changes have primarily driven decline in B. houstonensis with population supplementation predominant among efforts to reduce its current extinction risk. However, there has been historic uncertainty regarding the evolutionary and conservation significance of B. houstonensis. To this end, we used 1170 genome-wide nuclear DNA markers to examine phylogenetic relationships between our focal taxon, representatives of the Nearctic B. americanus group, and B. nebulifer, a sympatric Middle American species. Phylogenetic analyses indicate B. houstonensis is a taxon that is distinct from B. americanus. We corroborated such genetic distinctiveness with an admixture analysis that provided support for recent reproductive isolation between B. americanus and B. houstonensis. However, ABBA-BABA tests for ancient admixture indicated historic gene flow between Nearctic species while no signal of historic gene flow was detected between Nearctic and Middle-American species. We used an admixture analysis to recognize four Management Units (MU) based on observed genetic differentiation within B. houstonensis and recommend captive propagation, population supplementation, and habitat restoration efforts specific to each MU. Our results re-affirm the evolutionary novelty of an endangered relict.

Using the Fossil Record to Understand Extinction Risk and Inform Marine Conservation in a Changing World.

Understanding the long-term effects of ongoing global environmental change on marine ecosystems requires a cross-disciplinary approach. Deep-time and recent fossil records can contribute by identifying traits and environmental conditions associated with elevated extinction risk during analogous events in the geologic past and by providing baseline data that can be used to assess historical change and set management and restoration targets and benchmarks. Here, we review the ecological and environmental information available in the marine fossil record and discuss how these archives can be used to inform current extinction risk assessments as well as marine conservation strategies and decision-making at global to local scales. As we consider future research directions in deep-time and conservationpaleobiology, we emphasize the need for coproduced research that unites researchers, conservation practitioners, and policymakers with the communities for whom the impacts of climate and global change are most imminent.

Red List of lichenized fungi in Bulgaria

The first Red List assessment of lichenized fungi reported from Bulgaria is presented. The IUCN Red List criteria were applied to 138 species to assess their current extinction risk and to highlight the main threats for them. Our results revealed that six species are Regionally Extinct (RE), 23 species are Critically Endangered (CR), 20 species are Endangered (EN), 13 species are Vulnerable (VU), 11 species are Near Threatened (NT), 58 species are Least Concern (LC), and seven species are Data Deficient (DD). The most important floristic regions for lichen conservation are the Pirin Mts (26 species), the Balkan Range (25), the Rila Mts (25), the Rhodopes (20), Mt. Vitosha (16), Mt. Strandzha (16), and the Black Sea coast (15). The main threats are development of tourism and recreation activities that destroy habitats (60 species affected), air pollution (55), climate change (53), development of tourism and recreation areas (41), harvesting trees and other woody vegetation (unintentional effects) (27), ecosystem modifications that convert or degrade habitats (18), and development of housing and urban areas (14). The information provided in this Red List will assist to further develop the national conservation strategy for Bulgaria.

Glimmers of hope in large carnivore recoveries

In the face of an accelerating extinction crisis, scientists must draw insights from successful conservation interventions to uncover promising strategies for reversing broader declines. Here, we synthesize cases of recovery from a list of 362 species of large carnivores, ecologically important species that function as terminal consumers in many ecological contexts. Large carnivores represent critical conservation targets that have experienced historical declines as a result of direct exploitation and habitat loss. We examine taxonomic and geographic variation in current extinction risk and recovery indices, identify conservation actions associated with positive outcomes, and reveal anthropogenic threats linked to ongoing declines. We find that fewer than 10% of global large carnivore populations are increasing, and only 12 species (3.3%) have experienced genuine improvement in extinction risk, mostly limited to recoveries among marine mammals. Recovery is associated with species legislation enacted at national and international levels, and with management of direct exploitation. Conversely, ongoing declines are robustly linked to threats that include habitat modification and human conflict. Applying lessons from cases of large carnivore recovery will be crucial for restoring intact ecosystems and maintaining the services they provide to humans.

High-Quality Reference Genome for an Arid-Adapted Mammal, the Banner-Tailed Kangaroo Rat (Dipodomys spectabilis)

Kangaroo rats in the genus Dipodomys are found in a variety of habitat types in western North America, including deserts, arid and semiarid grasslands, and scrublands. Many Dipodomys species are experiencing strong population declines due to increasing habitat fragmentation, with two species listed as federally endangered in the United States. The precarious state of many Dipodomys populations, including those occupying extreme environments, make species of this genus valuable subjects for studying the impacts of habitat degradation and fragmentation on population genomic patterns and for characterizing the genomic bases of adaptation to harsh conditions. To facilitate exploration of such questions, we assembled and annotated a reference genome for the banner-tailed kangaroo rat (Dipodomys spectabilis) using PacBio HiFi sequencing reads, providing a more contiguous genomic resource than two previously assembled Dipodomys genomes. Using the HiFi data for D. spectabilis and publicly available sequencing data for two other Dipodomys species (Dipodomys ordii and Dipodomys stephensi), we demonstrate the utility of this new assembly for studies of congeners by conducting inference of historic effective population sizes (Ne) and linking these patterns to the species’ current extinction risk statuses. The genome assembly presented here will serve as a valuable resource for population and conservation genomic studies of Dipodomys species, comparative genomic research within mammals and rodents, and investigations into genomic adaptation to extreme environments and changing landscapes.

Red list of threatened vascular plants in Italy

Italy has a rich natural heritage, which is dangerously under pressure. In recent years, there is an increased awareness of the crucial role of plants in ecosystem functioning and in providing ecosystem services. Consequently, an updated Red List of the Italian vascular flora was compiled in this work, at the request of the Ministry for Environment, Land and Sea Protection, with the scientific support of the Italian Botanical Society. The IUCN Red List criteria were applied to 2,430 Italian native vascular plant taxa to assess their current extinction risk and to highlight the major threats affecting the Italian flora. Our results revealed that 54 taxa (2.2% of the assessed taxa) are extinct or possibly extinct at regional level, while 590 taxa (24.3%) were assigned to a risk category. Moreover, 404 taxa (16.6%) were categorized as Data Deficient. The Italian vascular flora is primarily threatened by habitat modifications due to anthropic disturbance and, especially, to agriculture, tourism and residential development. Coastal areas and lowlands, where anthropogenic impacts and ecosystem destruction are more pronounced, host the greatest number of extinct or declining taxa. Our results represent an important baseline to establish conservation priorities, legislative choices and intervention strategies on a national scale.

Range area matters, and so does spatial configuration: predicting conservation status in vertebrates

The current rapid loss of biodiversity globally calls for improved tools to predict conservation status. Conservation status varies among taxa and is influenced by intrinsic species’ traits and extrinsic factors. Among these predictors, the most consistently recognized and widely available is geographic range area. However, ranges of equal area can have diverse spatial configurations that reflect variation in threatening processes and species’ characteristics (e.g. dispersal ability), and can affect local and regional population dynamics. The aim of this study is to assess if and how the spatial configuration of a species’ range relates to its conservation status. We obtained range maps and two descriptors of conservation status: extinction risk and population trend, from the IUCN for 11 052 species of amphibians, non‐marine birds and terrestrial mammals distributed across the World. We characterized spatial configuration using descriptors of shape and fragmentation (fragment number and size heterogeneity) and used regression analysis to evaluate their role in explaining current extinction risk and population trend. The most important predictor of conservation status was range area, but our analyses also identified shape and fragmentation as valuable predictors. We detected complex relationships, revealed by multiple interaction terms, e.g. more circular shapes were negatively correlated with population trend, and heterogeneity was positively correlated with extinction risk for small range areas but negatively for bigger ranges. Considering descriptors of spatial configuration beyond size improves our understanding of conservation status among vertebrates. The metrics we propose are relatively easy to define (although values can be sensitive to data quality), and unlike other correlates of status, like species’ traits, are readily available for many species (all of those with range maps). We argue that considering spatial configuration predictors is a straightforward way to improve our capacity to predict conservation status and thus, can be useful to promote more effective conservation.

Chemical antipredator defence is linked to higher extinction risk.

Many attributes of species may be linked to contemporary extinction risk, though some such traits remain untested despite suggestions that they may be important. Here, I test whether a trait associated with higher background extinction rates, chemical antipredator defence, is also associated with current extinction risk, using amphibians as a model system—a group facing global population declines. I find that chemically defended species are approximately 60% more likely to be threatened than species without chemical defence, although the severity of the contemporary extinction risk may not relate to chemical defence. The results confirm that background and contemporary extinction rates can be predicted from the same traits, at least in certain cases. This suggests that associations between extinction risk and phenotypic traits can be temporally stable over long periods. The results also provide novel insights into the relevance of antipredator defences for species subject to conservation concerns.

Amphibians over the edge: silent extinction risk of Data Deficient species

AbstractAimTo apply mathematical models to the task of predicting extinction risk for species currently listed as ‘Data Deficient’ (DD) by the International Union for the Conservation of Nature (IUCN). We demonstrate this approach by applying it globally to amphibians, the vertebrate group recognized as being most extinction threatened and having the largest proportion of DD species. We combine model predictions with current extinction risk knowledge to highlight regions of greatest disparity between known and predicted risk, where potential species extinctions may be overlooked.LocationGlobal.MethodsUsing global amphibian distribution data obtained from the IUCN and species trait data, we apply machine learning randomForest models to predict extinction risk of DD species from life history traits, environmental variables and habitat loss. These models are trained using data for species that have been assigned to an extinction risk category (other than DD) by the IUCN. We then combine predictions for DD species with IUCN assessment data in a GIS framework to highlight anomalies between current knowledge of amphibian extinction risk and our model predictions.ResultsWe show that DD amphibian species are likely to be more threatened with extinction than their fully assessed counterparts. Regions in South America, central Africa and North Asia are particularly at risk due to lack of species knowledge and higher extinction risk than currently recognized.Main conclusionsApplication of predictive models ranking regions and species most in need of primary research allows prioritization of limited resources in an informed context, minimizing risk of unnoticed species' extinction.

Critical‐weight‐range marsupials in northern Australia are declining: a commentary on Fisher et al. (2014) ‘The current decline of tropical marsupials in Australia: is history repeating?’

AbstractMany mammal species are declining in parts of Australia's tropical savannas, for reasons that are not yet well defined. A recent paper (Fisher et al., 2014, Global Ecology and Biogeography, 23, 181–190) suggested that the primary cause is predation by feral cats, with the main evidence presented being a purported over‐representation of small species amongst the marsupials that have contracted in range (‘small body size signifies high current extinction risk’). However, a review here of the information presented in that paper shows that no marsupial species smaller than 100 g has shown range contraction in northern Australia, and that most (15 of 17) declines are of species in the ‘critical weight range’ (35 g to 5.5 kg).

A comparison of current and reconstructed historic geographic range sizes as predictors of extinction risk in Australian mammals

Comparative studies of extinction risk in vertebrate taxa often find that a small geographic range size is the strongest predictor of a high rate of species decline. This suggests that narrowly distributed species are more vulnerable to human impacts, which may have implications for the predictive use of comparative extinction-risk models in conservation planning. However, this association is potentially circular because many species that have suffered substantial declines now have small geographic ranges, making it difficult to separate the role of range size as a predictor of extinction risk from its role as a response to human impact. Here we use data for Australian mammals to compare models of extinction risk that include current geographic range size with models that include historic range sizes reconstructed for the period before European settlement. We find that current range size is a strong predictor of a species’ IUCN Red List classification. However, when historic range sizes are used, range size is non-significant and life-history traits assume primary importance in the model. Models that include current range size also tend to underestimate levels of latent extinction risk (the discrepancy between a species’ current extinction risk and that predicted from its biological traits), giving misleading predictions of the species and regions with greatest potential for future species declines. The results suggest that there is circularity in the use of current range size to predict rates of species decline, and that species with inherently small distributions are not necessarily the most vulnerable to human impact.

Primate extinction risk and historical patterns of speciation and extinction in relation to body mass

Body mass is thought to influence diversification rates, but previous studies have produced ambiguous results. We investigated patterns of diversification across 100 trees obtained from a new Bayesian inference of primate phylogeny that sampled trees in proportion to their posterior probabilities. First, we used simulations to assess the validity of previous studies that used linear models to investigate the links between IUCN Red List status and body mass. These analyses support the use of linear models for ordinal ranked data on threat status, and phylogenetic generalized linear models revealed a significant positive correlation between current extinction risk and body mass across our tree block. We then investigated historical patterns of speciation and extinction rates using a recently developed maximum-likelihood method. Specifically, we predicted that body mass correlates positively with extinction rate because larger bodied organisms reproduce more slowly, and body mass correlates negatively with speciation rate because smaller bodied organisms are better able to partition niche space. We failed to find evidence that extinction rates covary with body mass across primate phylogeny. Similarly, the speciation rate was generally unrelated to body mass, except in some tests that indicated an increase in the speciation rate with increasing body mass. Importantly, we discovered that our data violated a key assumption of sample randomness with respect to body mass. After correcting for this bias, we found no association between diversification rates and mass.

Latent extinction risk and the future battlegrounds of mammal conservation.

Global conservation prioritization usually emphasizes areas with highest species richness or where many species are thought to be at imminent risk of extinction. However, these strategies may overlook areas where many species have biological traits that make them particularly sensitive to future human impact but are not yet threatened because such impact is currently low. In this article, we identify such areas for the world's mammals using latent extinction risk, the discrepancy between a species' current extinction risk and that predicted from models on the basis of biological traits. Species with positive latent risk are currently less threatened than their biology would suggest, usually because they inhabit regions or habitats still comparatively unmodified by human activity. Using large new geographic, biological, and phylogenetic databases for nearly 4,000 mammal species, we map the global geographic distribution of latent risk to reveal areas where the mammal fauna is still relatively unthreatened but has high inherent sensitivity to disturbance. These hotspots include large areas such as the Nearctic boreal forests and tundra that are unrepresented in most current prioritization schemes, as well as high-biodiversity areas such as the island arc from Indonesia to the south Pacific. Incorporating latent extinction risk patterns into conservation planning could help guard against future biodiversity loss by anticipating and preventing species declines before they begin.

Evaluation of the extinction risk and of conservation alternatives for a very small insular population: the bearded vulture Gypaetus barbatus in Corsica

The bearded vulture Gypaetus barbatus is a large, long-lived osteophagus vulture whose abundance and breeding range have drastically declined during the last century, making it one of the most endangered European bird species. We evaluated the extinction risk of the bearded vulture population in Corsica (a small, isolated breeding population of 8–10 pairs), one of the last extant populations in Western Europe, and estimated its probability of extinction to be 0.165 over the next 50 years. A sensitivity analysis to assess the influence of uncertain demographic rates showed that it is critical to estimate precisely the values of pre-adult survival. Neither the type nor the parameters of density dependence acting on fecundity and survival rates influenced much the extinction risk of the Corsican population. We evaluated the effect of four realistic conservation actions that could be implemented on the Corsican bearded vulture population and rank them in terms of their respective decrease of the current extinction risk faced by this population. We found that the release of two juveniles every other year for 12 years and the increase of fecundity due to selective food provisioning would reduce by more than one-half the current extinction risk of Corsican bearded vulture population. In contrast, even substantial increases in the carrying capacity through large supplemental feeding produced very modest decreases in the extinction risk, thus calling into question the efficacy of one of the main pan-European conservation strategies for this species. Re-establishing a population network within the Mediterranean could be a potentially better strategy, though its efficacy depends on natal dispersal among populations that is currently unknown.

Nonrandom extinction and the loss of evolutionary history.

The hierarchical nature of phylogenies means that random extinction of species affects a smaller fraction of higher taxa, and so the total amount of evolutionary history lost may be comparatively slight. However, current extinction risk is not phylogenetically random. We show the potentially severe implications of the clumped nature of threat for the loss of biodiversity. An additional 120 avian and mammalian genera are at risk compared with the number predicted under random extinction. We estimate that the prospective extra loss of mammalian evolutionary history alone would be equivalent to losing a monotypic phylum.