Bruce E. Young

International Union for Conservation of Nature, Vaud, Switzerland

Are you Bruce E. Young?

Claim your profile

Publications (34)288.17 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Recognizing the imperiled status of biodiversity and its benefit to human well-being, the world's governments committed in 2010 to take effective and urgent action to halt biodiversity loss through the Convention on Biological Diversity's “Aichi Targets”. These targets, and many conservation programs, require monitoring to assess progress toward specific goals. However, comprehensive and easily understood information on biodiversity trends at appropriate spatial scales is often not available to the policy makers, managers, and scientists who require it. We surveyed conservation stakeholders in three geographically diverse regions of critical biodiversity concern (the Tropical Andes, the African Great Lakes, and the Greater Mekong) and found high demand for biodiversity indicator information but uneven availability. To begin to address this need, we present a biodiversity “dashboard” – a visualization of biodiversity indicators designed to enable tracking of biodiversity and conservation pe
    PLoS ONE 11/2014; 9(11):e112046. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: New tools and approaches are becoming available for wildlife conservation managers to help support climate adaptation activities, but few studies have documented how practitioners have applied these tools and perceive their utility. We surveyed the literature and users of the NatureServe Climate Change Vulnerability Index (CCVI), a tool that is widely used in North America to assess species' vulnerability to climate change, to characterize 1) how the tool has been used; 2) the objectives addressed by projects using the tool; 3) novel approaches that might be useful to other users; 4) how the results contributed to climate change adaptation planning; and 5) needed improvements recognized by users of the tool. Responses from 25 CCVI users, representing state agencies and natural heritage programs, conservation organizations, and universities, combined with published reports from 20 CCVI assessments, indicated that the CCVI has been applied to large numbers of species from diverse taxonomic groups. Results from these assessments have been used to communicate about climate change vulnerability, select species to be prioritized for management, inform management decisions, identify monitoring needs, and inform land-acquisition decisions. Users of the CCVI have developed novel ways to address uncertainty in climate and species natural-history data, involve stakeholders, evaluate migratory species, address specific management questions, and combine outputs with the results of parallel spatial analyses. To address user needs, future iterations of the tool should address climate exposure in the full life cycle of migratory species; better examine species dependent on specific vegetation microhabitats; and improve treatment of the effects of climate on diseases, parasites, and natural enemies. © 2014 The Wildlife Society.
    Wildlife Society Bulletin 11/2014; · 0.95 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 1.Despite efforts in data collection, missing values are commonplace in life-history trait databases. Because these values typically are not missing randomly, the common practice of removing missing data not only reduces sample size, but also introduces bias that can lead to incorrect conclusions. Imputing missing values is a potential solution to this problem. Here, we evaluate the performance of four approaches for estimating missing values in trait databases (K-nearest neighbour (kNN), multivariate imputation by chained equations (mice), missForest and Phylopars), and test whether imputed datasets retain underlying allometric relationships among traits.2.Starting with a nearly complete trait dataset on the mammalian order Carnivora (using four traits), we artificially removed values so that the percent of missing values ranged from 10 to 80%. Using the original values as a reference, we assessed imputation performance using normalized root mean squared error. We also evaluated whether including phylogenetic information improved imputation performance in kNN, mice, and missForest (it is a required input in Phylopars). Finally, we evaluated the extent to which the allometric relationship between two traits (body mass and longevity) was conserved for imputed datasets by looking at the difference (bias) between the slope of the original and the imputed datasets or datasets with missing values removed.3.Three of the tested approaches (mice, missForest and Phylopars), resulted in qualitatively equivalent imputation performance, and all had significantly lower errors than kNN. Adding phylogenetic information into the imputation algorithms improved estimation of missing values for all tested traits. The allometric relationship between body mass and longevity was conserved when up to 60% of data were missing, either with or without phylogenetic information, depending on the approach. This relationship was less biased in imputed datasets compared to datasets with missing values removed, especially when more than 30% of values were missing.4.Imputations provide valuable alternatives to removing missing observations in trait databases as they produce low errors and retain relationships among traits. Although we must continue to prioritize data collection on species traits, imputations can provide a valuable solution for conducting macroecological and evolutionary studies using life-history trait databases.This article is protected by copyright. All rights reserved.
    Methods in Ecology and Evolution 07/2014; · 5.92 Impact Factor
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Effective and targeted conservation action requires detailed information about species, their distribution, systematics and ecology as well as the distribution of threat processes which affect them. Knowledge of reptilian diversity remains surprisingly disparate, and innovative means of gaining rapid insight into the status of reptiles are needed in order to highlight urgent conservation cases and inform environmental policy with appropriate biodiversity information in a timely manner. We present the first ever global analysis of extinction risk in reptiles, based on a random representative sample of 1500 species (16% of all currently known species). To our knowledge, our results provide the first analysis of the global conservation status and distribution patterns of reptiles and the threats affecting them, highlighting conservation priorities and knowledge gaps which need to be addressed urgently to ensure the continued survival of the world’s reptiles. Nearly one in five reptilian species are threatened with extinction, with another one in five species classed as Data Deficient. The proportion of threatened reptile species is highest in freshwater environments, tropical regions and on oceanic islands, while data deficiency was highest in tropical areas, such as Central Africa and Southeast Asia, and among fossorial reptiles. Our results emphasise the need for research attention to be focussed on tropical areas which are experiencing the most dramatic rates of habitat loss, on fossorial reptiles for which there is a chronic lack of data, and on certain taxa such as snakes for which extinction risk may currently be underestimated due to lack of population information. Conservation actions specifically need to mitigate the effects of humaninduced habitat loss and harvesting, which are the predominant threats to reptiles.
    Biological Conservation 01/2013; 157:372-385. · 3.79 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Effective and targeted conservation action requires detailed information about species, their distribution, systematics and ecology as well as the distribution of threat processes which affect them. Knowledge of reptilian diversity remains surprisingly disparate, and innovative means of gaining rapid insight into the status of reptiles are needed in order to highlight urgent conservation cases and inform environmental policy with appropriate biodiversity information in a timely manner. We present the first ever global analysis of extinction risk in reptiles, based on a random representative sample of 1500 species (16% of all currently known species). To our knowledge, our results provide the first analysis of the global conservation status and distribution patterns of reptiles and the threats affecting them, highlighting conservation priorities and knowledge gaps which need to be addressed urgently to ensure the continued survival of the world’s reptiles. Nearly one in five reptilian species are threatened with extinction, with another one in five species classed as Data Deficient. The proportion of threatened reptile species is highest in freshwater environments, tropical regions and on oceanic islands, while data deficiency was highest in tropical areas, such as Central Africa and Southeast Asia, and among fossorial reptiles. Our results emphasise the need for research attention to be focussed on tropical areas which are experiencing the most dramatic rates of habitat loss, on fossorial reptiles for which there is a chronic lack of data, and on certain taxa such as snakes for which extinction risk may currently be underestimated due to lack of population information. Conservation actions specifically need to mitigate the effects of human induced habitat loss and harvesting, which are the predominant threats to reptiles.
    Biological Conservation 01/2013; 157:372-385. · 3.79 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: The Andes-Amazon basin of Peru and Bolivia is one of the most data-poor, biologically rich, and rapidly changing areas of the world. Conservation scientists agree that this area hosts extremely high endemism, perhaps the highest in the world, yet we know little about the geographic distributions of these species and ecosystems within country boundaries. To address this need, we have developed conservation data on endemic biodiversity (~800 species of birds, mammals, amphibians, and plants) and terrestrial ecological systems (~90; groups of vegetation communities resulting from the action of ecological processes, substrates, and/or environmental gradients) with which we conduct a fine scale conservation prioritization across the Amazon watershed of Peru and Bolivia. We modelled the geographic distributions of 435 endemic plants and all 347 endemic vertebrate species, from existing museum and herbaria specimens at a regional conservation practitioner's scale (1:250,000-1:1,000,000), based on the best available tools and geographic data. We mapped ecological systems, endemic species concentrations, and irreplaceable areas with respect to national level protected areas. Results: We found that sizes of endemic species distributions ranged widely (< 20 km 2 to > 200,000 km
    12/2012;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Andes-Amazon basin of Peru and Bolivia is one of the most data-poor, biologically rich, and rapidly changing areas of the world. Conservation scientists agree that this area hosts extremely high endemism, perhaps the highest in the world, yet we know little about the geographic distributions of these species and ecosystems within country boundaries. To address this need, we have developed conservation data on endemic biodiversity (~800 species of birds, mammals, amphibians, and plants) and terrestrial ecological systems (~90; groups of vegetation communities resulting from the action of ecological processes, substrates, and/or environmental gradients) with which we conduct a fine scale conservation prioritization across the Amazon watershed of Peru and Bolivia. We modelled the geographic distributions of 435 endemic plants and all 347 endemic vertebrate species, from existing museum and herbaria specimens at a regional conservation practitioner's scale (1:250,000-1:1,000,000), based on the best available tools and geographic data. We mapped ecological systems, endemic species concentrations, and irreplaceable areas with respect to national level protected areas. We found that sizes of endemic species distributions ranged widely (< 20 km2 to > 200,000 km2) across the study area. Bird and mammal endemic species richness was greatest within a narrow 2500-3000 m elevation band along the length of the Andes Mountains. Endemic amphibian richness was highest at 1000-1500 m elevation and concentrated in the southern half of the study area. Geographical distribution of plant endemism was highly taxon-dependent. Irreplaceable areas, defined as locations with the highest number of species with narrow ranges, overlapped slightly with areas of high endemism, yet generally exhibited unique patterns across the study area by species group. We found that many endemic species and ecological systems are lacking national-level protection; a third of endemic species have distributions completely outside of national protected areas. Protected areas cover only 20% of areas of high endemism and 20% of irreplaceable areas. Almost 40% of the 91 ecological systems are in serious need of protection (= < 2% of their ranges protected). We identify for the first time, areas of high endemic species concentrations and high irreplaceability that have only been roughly indicated in the past at the continental scale. We conclude that new complementary protected areas are needed to safeguard these endemics and ecosystems. An expansion in protected areas will be challenged by geographically isolated micro-endemics, varied endemic patterns among taxa, increasing deforestation, resource extraction, and changes in climate. Relying on pre-existing collections, publically accessible datasets and tools, this working framework is exportable to other regions plagued by incomplete conservation data.
    BMC Ecology 01/2012; 12:1.
  • Source
    PLoS Biology 10/2010; · 12.69 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Using data for 25,780 species categorized on the International Union for Conservation of Nature Red List, we present an assessment of the status of the world's vertebrates. One-fifth of species are classified as Threatened, and we show that this figure is increasing: On average, 52 species of mammals, birds, and amphibians move one category closer to extinction each year. However, this overall pattern conceals the impact of conservation successes, and we show that the rate of deterioration would have been at least one-fifth again as much in the absence of these. Nonetheless, current conservation efforts remain insufficient to offset the main drivers of biodiversity loss in these groups: agricultural expansion, logging, overexploitation, and invasive alien species.
    Science 10/2010; 330(6010):1503-9. · 31.20 Impact Factor
  • Source
    Bruce E. Young
    [Show abstract] [Hide abstract]
    ABSTRACT: Con el fin de mejorar la precisión de nuestro conocimiento de las áreas de endemismo para aves en la vertiente oriental de los Andes en Perú y Bolivia, una de las regiones faunísticas más diversas del mundo, utilizamos modelos de distributión basados en registros de localidad y 10–12 variables ambientales no-correlacionadas para mapear las distribuciones de 115 especies. Los resultados, derivados del algoritmo de entropía máxima y de modelos deductivos, muestran tres áreas de endemismo que respaldan en general las evaluaciones anteriores de endemismo hechas en la región, pero con mucho más detalle. Las regiones como el sur-occidente de la Cordillera de Vilcabamba y el valle del Río Mapacho-Yavero en Cusco, Perú, y la Cordillera de Apolobamba en el occidente de Bolivia albergan una diversidad de especies endémicas más alta de lo que se ha reconocido anteriormente. Este resultado probablemente se debe a la característica de los modelos predictivos de controlar, en parte, el sesgo por esfuerzo de muestreo. Las áreas protegidas al nivel nacional cubren por lo menos 1.000 km2 de las distribuciones, o cuatro quintos de las distribuciones de las especies con rangos de menos de 1.000 km2, del 77% de las especies endémicas. No obstante, un análisis de la irreemplazabilidad total, que da énfasis a las localidades de las especies con los rangos más reducidos, demostró que solamente el 18% de estas áreas críticas están protegidas en la actualidad. Los mapas de escala fina de las áreas de endemismo pueden permitir la planificaión de la conservación tanto al nivel local como al nivel regional, actividades que pueden llenar los vacíos de protección actuales de muchas especies.
    The Auk 08/2009; · 2.40 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Seeking more precise knowledge of avian endemism on the east slope of the Andes in Peru and Bolivia, one of the most diverse faunal regions on Earth, we used distribution models based on locality records and 10–12 uncorrelated environmental variables to map the distributions of 115 species. Both maximum-entropy and deductive models reveal three areas of endemism, broadly supporting previous assessments of endemism in the region but showing much more detail. Regions such as the southwestern Cordillera de Vilcabamba and the Río Mapacho-Yavero valley in Cusco, Peru, and the Cordillera de Apolobamba in western Bolivia support a greater richness of endemic species than has been recognized, a result likely attributable to the ability of predictive models to partially control for biases in survey effort. National-level protected areas cover ≥1,000 km2 of the ranges, or four-fifths of the ranges of species with distributions <1,000 km2, of 77% of the endemic species. However, an analysis of summed irreplaceability, which emphasizes the locations of the most narrowly distributed endemics, showed that only 18% of these critical areas are currently protected. The fine-scale maps of endemic areas are suitable for regional and local-scale conservation planning, activities that can fill current gaps in protection of many species.
    The Auk 07/2009; 126(3):554-565. · 2.40 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Book review of Stuart et al. (2008) "Threatened amphibians of the world".
    Alytes. 05/2009; 27(1):25-37.
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action.
    Science 11/2008; 322(5899):225-30. · 31.20 Impact Factor
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action.
    Science 10/2008; 322(5899):225-230. · 31.20 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Although open-cup nesting birds generally face increased risk of nest depredation from forest edge predators and brood parasites in fragmented temperate landscapes, little information exists to assess such risks in tropical birds. We compared nesting success of real birds' nests in large and small forest fragments to a control site in Caribbean lowland wet forest of Costa Rica. Pooling across species, nesting success was significantly greater in unfragmented forest than in either small, isolated fragments or the La Selva Biological Reserve, which is at the tip of a forest ‘peninsula’ embedded in a largely deforested landscape. Nesting success in isolated fragments did not vary according to distance from edge, suggesting that predators in fragments act throughout these forest patches. The case for increased nest predation as a plausible mechanism to explain the documented decline of forest interior bird populations in this fragmented tropical landscape is enhanced by a simple demographic model that suggests nesting success is likely too low to maintain populations at La Selva and in the fragments. The fact that the large (> 1000 ha) La Selva forest reserve is experiencing nest predation rates similar to those in much smaller fragments is cause for concern. Our results make a strong case for additional studies to document the identities of nest predators in both fragmented and unfragmented forests in such tropical forest landscapes.RESUMENA pesar de que en los paisajes fragmentados de las zonas templadas las aves que construyen nidos en la forma de un tazón abierto se enfrentan riesgos elevados de depredación de sus nidos por los depredadores que abundan en los bordes del bosque y a los parásitos de cría, existe poca información para evaluar estos riegos para las aves tropicales. Comparamos el éxito de los nidos verdaderos de las aves en grande y pequeñas parcelas de bosque a un sitio de control en el bosque húmedo de las zonas bajas en el Caribe de Costa Rica. Agrupando los resultados para todas las especies, resultó que el éxito de anidación fue significativamente menor en el bosque no fragmentado que tanto en las parcelas pequeñas de bosque como en la Reserva Biológica La Selva, que se ubica en el punto de una península de bosque rodeado por deforestación. Un modelo demográfico sencillo apoya la idea de que el aumento de depredación de nidos es un mecanismo factible para explicar la disminución de las poblaciones de las aves del interior del bosque en este paisaje tropical fragmentado. El hecho de que la gran (> 1.000 ha) reserva forestal de La Selva se experimenta una tasa de depredación de nidos similar a la de fragmentos mucho menores se preocupa. Nuestros resultados hacen hincapié a la necesidad para investigaciones adicionales con el fin de documentar las identidades de los depredadores de nidos tanto en los bosques fragmentados como en los bosques no fragmentados en los paisajes en zonas bajas de bosque húmedo.
    Biotropica 08/2008; 40(5):615 - 622. · 2.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Conservationists are increasingly relying on distribution models to predict where species are likely to occur, especially in poorly-surveyed but biodiverse areas. Modeling is challenging in these cases because locality data necessary for model formation are often scarce and spatially imprecise. To identify methods best suited to modeling in these conditions, we compared the success of three algorithms (Maxent, Mahalanobis Typicalities and Random Forests) at predicting distributions of eight bird and eight mammal species endemic to the eastern slopes of the central Andes. We selected study species to have a range of locality sample sizes representative of the data available for endemic species of this region and also that vary in their distribution characteristics. We found that for species that are known from moderate numbers (N=38–94) of localities, the three methods performed similarly for species with restricted distributions but Maxent and Random Forests yielded better results for species with wider distributions. For species with small numbers of sample localities (N=5–21), Maxent produced the most consistently successful results, followed by Random Forests and then Mahalanobis Typicalities. Because evaluation statistics for models derived from few localities can be suspect due to the poor spatial representation of the evaluation data, we corroborated these results with review by scientists familiar with the species in the field. Overall, Maxent appears to be the most capable method for modeling distributions of Andean bird and mammal species because of the consistency of results in varying conditions, although the other methods have strengths in certain situations.
    Biodiversity and Conservation 05/2008; 17(6):1353-1366. · 2.26 Impact Factor
  • Source
    Threatened Amphibians of the World, Edited by S.N. Stuart, M. Hoffmann, J.S. Chanson, N.A. Cox, R.J. Berridge, P. Ramani, Bruce Young, 01/2008: chapter Amphibians of the Neotropical Realm: pages 92-99; Lynx Edicions, Barcelona, Spain; IUCN, Gland, Switzerland; and Conservation International, Arlington, Virginia, USA..

Publication Stats

3k Citations
288.17 Total Impact Points

Top Journals

Institutions

  • 2008
    • International Union for Conservation of Nature
      Vaud, Switzerland
  • 2006–2008
    • Tulane University
      • Department of Ecology and Evolutionary Biology
      New Orleans, Louisiana, United States
  • 1213
    • Southern Illinois University Carbondale
      • Department of Zoology
      Carbondale, IL, United States