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Journal: Conservation biology : the journal of the Society for Conservation Biology


The IUCN Red List categories and criteria are the most widely used framework for assessing the relative extinction risk of species. The criteria are based on quantitative thresholds relating to the size, trends and structure of species' distributions and populations. However, data on these parameters are sparse and uncertain for many species and unavailable for others, potentially leading to their misclassification, or classification as Data Deficient. Here we propose an approach combining data on land-cover change and species-specific habitat preferences, population abundance and dispersal distance to estimate key parameters (extent of occurrence, maximum area of occupancy, population size and trend, and degree of fragmentation) and hence IUCN Red List categories. We demonstrate the applicability of our approach for non-pelagic birds and terrestrial mammals globally (∼15,000 species), generating predictions fairly consistent with published Red List assessments, but more optimistic overall. We predict 4.2% of species (467 birds and 143 mammals) to be more threatened than currently assessed, and 20.2% of Data Deficient species (10 birds and 114 mammals) to be at risk of extinction. However, incorporating the habitat fragmentation sub-criterion reduced these predictions 1.5-2.3% and 6.4-14.9% (depending on the quantitative definition of fragmentation) of threatened and Data Deficient species respectively, highlighting the need for improved guidance to Red List assessors on applying this aspect of the Red List criteria. Our approach can be used to complement traditional methods of estimating parameters for Red List assessments. Furthermore, it can readily provide an early warning system to identify species potentially warranting changes in their extinction risk category based on periodic updates of land cover information. Given that our method relies on optimistic assumptions about species distribution and abundance, all species predicted to be more at risk than currently evaluated should be prioritized for reassessment. This article is protected by copyright. All rights reserved.


A key measure of humanity’s global impact is by how much it has increased species extinction rates. Familiar statements are that these are 100-1000 times pre-human or background extinction levels. Estimating recent rates is straightforward, but establishing a background rate for comparison is not. Previous researchers chose an approximate benchmark of 1 extinction per million species per year (E/MSY). We explored disparate lines of evidence that suggest a substantially lower estimate. Fossil data yield direct estimates of extinction rates, but they are temporally coarse, mostly limited to marine hard-bodied taxa, and generally involve genera not species. Based on these data, typical background loss is 0.01 genera per million genera per year. Molecular phylogenies are available for more taxa and ecosystems, but it is debated whether they can be used to estimate separately speciation and extinction rates. We selected data to address known concerns and used them to determine median extinction estimates from statistical distributions of probable values for terrestrial plants and animals. We then created simulations to explore effects of violating model assumptions. Finally, we compiled estimates of diversification-the difference between speciation and extinction rates for different taxa. Median estimates of extinction rates ranged from 0.023 to 0.135 E/MSY. Simulation results suggested over- and under-estimation of extinction from individual phylogenies partially canceled each other out when large sets of phylogenies were analyzed. There was no evidence for recent and widespread pre-human overall declines in diversity. This implies that average extinction rates are less than average diversification rates. Median diversification rates were 0.05-0.2 new species per million species per year. On the basis of these results, we concluded that typical rates of background extinction may be closer to 0.1 E/MSY. Thus, current extinction rates are 1,000 times higher than natural background rates of extinction and future rates are likely to be 10,000 times higher. Estimación de la Tasa Normal de Extinción de Especies.

Concepts: Conservation biology, Approximation, Plant, Normal distribution, Speciation, Extinction, Species, Evolution


Ingestion of marine debris can have lethal and sublethal effects on sea turtles and other wildlife. Although researchers have reported on ingestion of anthropogenic debris by marine turtles and implied incidences of debris ingestion have increased over time, there has not been a global synthesis of the phenomenon since 1985. Thus, we analyzed 37 studies published from 1985 to 2012 that report on data collected from before 1900 through 2011. Specifically, we investigated whether ingestion prevalence has changed over time, what types of debris are most commonly ingested, the geographic distribution of debris ingestion by marine turtles relative to global debris distribution, and which species and life-history stages are most likely to ingest debris. The probability of green (Chelonia mydas) and leatherback turtles (Dermochelys coriacea) ingesting debris increased significantly over time, and plastic was the most commonly ingested debris. Turtles in nearly all regions studied ingest debris, but the probability of ingestion was not related to modeled debris densities. Furthermore, smaller, oceanic-stage turtles were more likely to ingest debris than coastal foragers, whereas carnivorous species were less likely to ingest debris than herbivores or gelatinovores. Our results indicate oceanic leatherback turtles and green turtles are at the greatest risk of both lethal and sublethal effects from ingested marine debris. To reduce this risk, anthropogenic debris must be managed at a global level. Análisis Global de la Ingesta de Residuos Antropogénicos por Tortugas Marinas.

Concepts: Ingestion, Sea turtles, Costa Rica, Kemp's Ridley, Hawksbill turtle, Green turtle, Leatherback turtle, Sea turtle


United States and Canadian governments have responded to legal requirements to reduce human-induced whale mortality via vessel strikes and entanglement in fishing gear by implementing a suite of regulatory actions. We analyzed the spatial and temporal patterns of mortality of large whales in the Northwest Atlantic (23.5°N to 48.0°N), 1970 through 2009, in the context of management changes. We used a multinomial logistic model fitted by maximum likelihood to detect trends in cause-specific mortalities with time. We compared the number of human-caused mortalities with U.S. federally established levels of potential biological removal (i.e., species-specific sustainable human-caused mortality). From 1970 through 2009, 1762 mortalities (all known) and serious injuries (likely fatal) involved 8 species of large whales. We determined cause of death for 43% of all mortalities; of those, 67% (502) resulted from human interactions. Entanglement in fishing gear was the primary cause of death across all species (n = 323), followed by natural causes (n = 248) and vessel strikes (n = 171). Established sustainable levels of mortality were consistently exceeded in 2 species by up to 650%. Probabilities of entanglement and vessel-strike mortality increased significantly from 1990 through 2009. There was no significant change in the local intensity of all or vessel-strike mortalities before and after 2003, the year after which numerous mitigation efforts were enacted. So far, regulatory efforts have not reduced the lethal effects of human activities to large whales on a population-range basis, although we do not exclude the possibility of success of targeted measures for specific local habitats that were not within the resolution of our analyses. It is unclear how shortfalls in management design or compliance relate to our findings. Analyses such as the one we conducted are crucial in critically evaluating wildlife-management decisions. The results of these analyses can provide managers with direction for modifying regulated measures and can be applied globally to mortality-driven conservation issues. Evaluación del Manejo para Mitigar Efectos Antropogénicos sobre Ballenas Mayores.

Concepts: Likelihood function, Logistic function, Regulation, Logistic map, Anthropogenic, Sustainability, Whale, Mortality rate


The rise of the Internet as a trade platform has resulted in a shift in the illegal wildlife trade. As a result of increased scrutiny that illegal wildlife trade is receiving, there are concerns that the online trade will move onto the darkweb. In this preliminary study, we provide a baseline of illegal wildlife trade on the darkweb. We downloaded and archived 9,852 items from the darkweb, then searched these based on a list of 121 keywords associated with illegal online wildlife trade, including 30 keywords associated with illegally traded elephant ivory on the surface web. Results were compared with known illegally traded items, specifically cannabis, cocaine and heroin. Of these 121 keywords, only four resulted in hits, of which only one was potentially linked to illegal wildlife trade. This sole case was the sale and discussion of Echinopsis pachanoi (San Pedro cactus), which has hallucinogenic properties. This negligible level of activity on the darkweb, compared to the open and burgeoning trade on the surface web, may indicate a lack of successful enforcement against illegal wildlife trade on the surface web, although other hypothesis are considered and explored. This article is protected by copyright. All rights reserved.

Concepts: Hordenine, All rights reserved, Copyright, Echinopsis lageniformis, Echinopsis peruviana, Psychedelic drug, Echinopsis pachanoi, Echinopsis


That at least some aspects of nature possess intrinsic value is considered by some an axiom of conservation. Others consider nature’s intrinsic value superfluous or anathema. This range of views among mainstream conservation professionals potentially threatens the foundation of conservation. One challenge in resolving this disparity is that disparaging portrayals of nature’s intrinsic value appear rooted in misconceptions and unfounded presumptions about what it means to acknowledge nature’s intrinsic value. That acknowledgment has been characterized as vacuous, misanthropic, of little practical consequence to conservation, adequately accommodated by economic valuation, and not widely accepted in society. We reviewed the philosophical basis for nature’s intrinsic value and the implications for acknowledging that value. Our analysis is rooted to the notion that when something possesses intrinsic value it deserves to be treated with respect for what it is, with concern for its welfare or in a just manner. From this basis, one can only conclude that nature’s intrinsic value is not a vacuous concept or adequately accommodated by economic valuation. Acknowledging nature’s intrinsic value is not misanthropic because concern for nature’s welfare (aside from its influence on human welfare) does not in any way preclude also being concerned for human welfare. The practical import of acknowledging nature’s intrinsic value rises from recognizing all the objects of conservation concern (e.g., many endangered species) that offer little benefit to human welfare. Sociological and cultural evidence indicates the belief that at least some elements of nature possess intrinsic value is widespread in society. Our reasoning suggests the appropriateness of rejecting the assertion that nature’s intrinsic value is anathema to conservation and accepting its role as an axiom. Evaluar si el Valor Intrínseco de la Naturaleza es un Axioma o un Anatema para la Conservación.

Concepts: Morality, Intrinsic value, Logic, Ethics, Value theory, Endangered species, Sociology, Meaning of life


Large marine protected areas (MPAs), each hundreds of thousands of square kilometers, have been set up by governments around the world over the last decade as part of efforts to reduce ocean biodiversity declines, yet their efficacy is hotly debated. The Chagos Archipelago MPA (640,000 km(2) ) (Indian Ocean) lies at the heart of this debate. We conducted the first satellite tracking of a migratory species, the green turtle (Chelonia mydas), within the MPA and assessed the species' use of protected versus unprotected areas. We developed an approach to estimate length of residence within the MPA that may have utility across migratory taxa including tuna and sharks. We recorded the longest ever published migration for an adult cheloniid turtle (3979 km). Seven of 8 tracked individuals migrated to distant foraging grounds, often ≥1000 km outside the MPA. One turtle traveled to foraging grounds within the MPA. Thus, networks of small MPAs, developed synergistically with larger MPAs, may increase the amount of time migrating species spend within protected areas. The MPA will protect turtles during the breeding season and will protect some turtles on their foraging grounds within the MPA and others during the first part of their long-distance postbreeding oceanic migrations. International cooperation will be needed to develop the network of small MPAs needed to supplement the Chagos Archipelago MPA. Uso de los Patrones de Migración a Larga Distancia de una Especie en Peligro de Extinción para Informar a la Planeación de la Conservación del Área Marina Protegida más Grande.

Concepts: Biodiversity, Turtle soup, Leatherback turtle, Bird migration, Marine Protected Area, Protected area, Coral reef, Human migration


Hybridization between endangered species and more common species is a significant problem in conservation biology because it may result in extinction or loss of adaptation. The historical reduction in abundance and geographic distribution of the American plains bison (Bison bison bison) and their recovery over the last 125 years is well documented. However, introgression from domestic cattle (Bos taurus) into the few remaining bison populations that existed in the late 1800s has now been identified in many modern bison herds. We examined the phenotypic effect of this ancestry by comparing weight and height of bison with cattle or bison mitochondrial DNA (mtDNA) from Santa Catalina Island, California (U.S.A.), a nutritionally stressful environment for bison, and of a group of age-matched feedlot bison males in Montana, a nutritionally rich environment. The environmental and nutritional differences between these 2 bison populations were very different and demonstrated the phenotypic effect of domestic cattle mtDNA in bison over a broad range of conditions. For example, the average weight of feedlot males that were 2 years of age was 2.54 times greater than that of males from Santa Catalina Island. In both environments, bison with cattle mtDNA had lower weight compared with bison with bison mtDNA, and on Santa Catalina Island, the height of bison with cattle mtDNA was lower than the height of bison with bison mtDNA. These data support the hypothesis that body size is smaller and height is lower in bison with domestic cattle mtDNA and that genomic integrity is important for the conservation of the American plains bison. Efectos Fenotípicos del ADN Mitocondrial de Ganado en el Bisonte Americano.

Concepts: Beef, Cattle, Bos, Gaur, Bovinae, Extinction, American Bison, Bison


Indian Himalayan basins are earmarked for widespread dam building, but aggregate effects of these dams on terrestrial ecosystems are unknown. We mapped distribution of 292 dams (under construction and proposed) and projected effects of these dams on terrestrial ecosystems under different scenarios of land-cover loss. We analyzed land-cover data of the Himalayan valleys, where dams are located. We estimated dam density on fifth- through seventh-order rivers and compared these estimates with current global figures. We used a species-area relation model (SAR) to predict short- and long-term species extinctions driven by deforestation. We used scatter plots and correlation studies to analyze distribution patterns of species and dams and to reveal potential overlap between species-rich areas and dam sites. We investigated effects of disturbance on community structure of undisturbed forests. Nearly 90% of Indian Himalayan valleys would be affected by dam building and 27% of these dams would affect dense forests. Our model projected that 54,117 ha of forests would be submerged and 114,361 ha would be damaged by dam-related activities. A dam density of 0.3247/1000 km(2) would be nearly 62 times greater than current average global figures; the average of 1 dam for every 32 km of river channel would be 1.5 times higher than figures reported for U.S. rivers. Our results show that most dams would be located in species-rich areas of the Himalaya. The SAR model projected that by 2025, deforestation due to dam building would likely result in extinction of 22 angiosperm and 7 vertebrate taxa. Disturbance due to dam building would likely reduce tree species richness by 35%, tree density by 42%, and tree basal cover by 30% in dense forests. These results, combined with relatively weak national environmental impact assessment and implementation, point toward significant loss of species if all proposed dams in the Indian Himalaya are constructed. Efectos Potenciales del Desarrollo Hidroeléctrico Actual y Propuesto sobre la Diversidad Biológica Terrestre en el Himalaya Hindú

Concepts: Impact assessment, Hydroelectricity, Himalayas, River, Extinction, Environmental impact assessment, Biodiversity, Dam


Land use and hunting are two major pressures on biodiversity in the tropics. Yet, their combined impacts have not been systematically quantified at a large scale. We estimated the effects of both pressures on the distributions of 1,884 tropical mammal species by integrating detailed land-use maps (1992 and 2015), species-specific habitat preference data, and a hunting pressure model. We further identified geographical hotspots and coolspots of the combined impacts, indicating priority areas for mitigation or prevention of the pressures. We found that land use is the main driver reducing the distribution of all mammal species considered. Yet, hunting pressure causes considerable additional reductions in large-bodied species' distributions. Together, land use and hunting reduced the distributions of species by 41% (± 30%) on average (year 2015). Overall, we found a small overlap between the pressures (2% on average), with land use contributing more to the loss (39% on average) than hunting (4% on average). However, hunting reduced the distribution of large mammals by 29% on average, hence large mammals suffered a disproportional amount of area loss by both pressures combined. We identified hotspots of combined pressures in the Gran Chaco, the Atlantic Forest or Thailand. In contrast, the Amazon and Congo basin, the Guianas, or Borneo were identified as coolspots. We further found that, overall, both impacts increased from 1992 to 2015, with losses in distribution increasing from 38 to 41% on average across the species. To effectively protect tropical mammals, conservation policies should address both pressures simultaneously, as their effects are highly complementary. Our spatially detailed and species-specific results may support future national and global conservation agendas, including the design of post-2020 protected area targets and strategies. Article Impact Statement: Tropical mammals have lost on average 40% of their original distribution due to the combined effect of hunting pressure and human land use. This article is protected by copyright. All rights reserved.