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Conservation Decisions (conservation + decision)
Selected AbstractsConfronting Uncertainty and Missing Values in Environmental Value Transfer as Applied to Species ConservationCONSERVATION BIOLOGY, Issue 5 2010SONIA AKTER conservación de especies; error de transferencia; incertidumbre; transferencia de valor ambiental; valores de no uso Abstract:,The nonuse (or passive) value of nature is important but time-consuming and costly to quantify with direct surveys. In the absence of estimates of these values, there will likely be less investment in conservation actions that generate substantial nonuse benefits, such as conservation of native species. To help overcome decisions about the allocation of conservation dollars that reflect the lack of estimates of nonuse values, these values can be estimated indirectly by environmental value transfer (EVT). EVT uses existing data or information from a study site such that the estimated monetary value of an environmental good is transferred to another location or policy site. A major challenge in the use of EVT is the uncertainty about the sign and size of the error (i.e., the percentage by which transferred value exceeds the actual value) that results from transferring direct estimates of nonuse values from a study to a policy site, the site where the value is transferred. An EVT is most useful if the decision-making framework does not require highly accurate information and when the conservation decision is constrained by time and financial resources. To account for uncertainty in the decision-making process, a decision heuristic that guides the decision process and illustrates the possible decision branches, can be followed. To account for the uncertainty associated with the transfer of values from one site to another, we developed a risk and simulation approach that uses Monte Carlo simulations to evaluate the net benefits of conservation investments and takes into account different possible distributions of transfer error. This method does not reduce transfer error, but it provides a way to account for the effect of transfer error in conservation decision making. Our risk and simulation approach and decision-based framework on when to use EVT offer better-informed decision making in conservation. Resumen:,El valor de no uso (o pasivo) de la naturaleza es importante pero su cuantificación con muestreos pasivos consume tiempo y es costosa. En ausencia de estimaciones de estos valores, es probable que haya menos inversión en acciones de conservación que generen beneficios de no uso sustanciales, tal como la conservación de especies nativas. Para ayudar a superar decisiones respecto a la asignación de dólares para conservación que reflejan la carencia de estimaciones de los valores de no uso, estos valores pueden ser estimados indirectamente por la transferencia de valor ambiental (TVA). La transferencia de valor ambiental utiliza datos existentes o información de un sitio de estudio de tal manera que el valor monetario estimado de un bien ambiental es transferido a otro sitio. Un reto mayor en el uso de TVA es la incertidumbre sobre la señal y el tamaño del error (i.e., el porcentaje en que el valor transferido excede al valor actual) que resulta de la transferencia de estimaciones directas de los valores de no uso de un sitio de estudio a uno político, el sitio adonde el valor es transferido. Una TVA es más útil si el marco de toma de decisiones no requiere información muy precisa y cuando la decisión de conservación está restringida por tiempo y recursos financieros. Para tomar en cuenta la incertidumbre en el proceso de toma de decisiones, se puede seguir una decisión heurística que guie el proceso de decisión e ilustre sobre las posibles ramificaciones de la decisión. Para tomar en cuenta la incertidumbre asociada con la transferencia de valores de un sitio a otro, desarrollamos un método de riesgo y simulación que utiliza simulaciones Monte Carlo para evaluar los beneficios netos de las inversiones de conservación y que considera posibles distribuciones diferentes de la transferencia de error. Este método no reduce el error de transferencia, pero proporciona una manera para considerar el efecto del error de transferencia en la toma de decisiones de conservación. Nuestro método de riesgo y simulación y el marco de referencia basado en decisones sobre cuando utilizar TVA permiten la toma de decisiones en conservación más informadas. [source] Assessing the Effectiveness of Reserve Acquisition Programs in Protecting Rare and Threatened SpeciesCONSERVATION BIOLOGY, Issue 6 2006WILL R. TURNER Lake Wales Ridge (Florida); especies en peligro; índice de protección; Lista Roja IUCN; matorral Abstract:,Measuring the effectiveness of reserve networks is essential to ensure that conservation objectives such as species persistence are being met. We devised a new approach for measuring the effectiveness of land conservation in protecting rare and threatened species and applied it to an ecosystem of global significance. We compiled detailed global distributional data for 36 rare and threatened plants and animals found in the Lake Wales Ridge ecosystem in central Florida (U.S.A.). For each species, we developed a set of protection indices based in part on criteria used to categorize species for the World Conservation Union's Red List. We calculated protection indexes under three different conservation scenarios: a past scenario, which assumed recent, major land-acquisition efforts never occurred; a current scenario, which assumed no additional areas are saved beyond what is currently protected; and a targeted scenario, which assumed all of the remaining areas targeted for protection are eventually acquired. This approach enabled us to quantify the progress, in terms of reduced risk of extinction, that conservationists have made in protecting target species. It also revealed the limited success these land-acquisition efforts have had in reducing those extinction risks associated with loss of habitat or small geographic ranges. Many species of the Lake Wales Ridge will remain at high risk of extinction even if planned land-acquisition efforts are completely successful. By calculating protection indexes with and without each site for all imperiled species, we also quantified the contribution of each protected area to the conservation of each species, enabling local conservation decisions to be made in the context of a larger (global) perspective. The protection index approach can be adapted readily to other ecosystems with multiple rare and threatened species. Resumen:,La cuantificación de la efectividad de las redes de reservas es esencial para asegurar que objetivos, como la persistencia de especies, se cumplan. Diseñamos un nuevo método para medir la efectividad de la conservación de tierras en la protección de especies raras y amenazadas y lo aplicamos a un ecosistema de importancia global. Compilamos datos detallados de la distribución global de 36 especies raras y amenazadas de plantas y animales que se encuentran en el ecosistema de la Lake Wales Ridge en el centro de Florida (E.U.A.). Para cada especie desarrollamos un conjunto de índices de protección basado parcialmente en criterios utilizados para clasificar especies para la Lista Roja de la Unión Mundial para la Naturaleza. Calculamos los índices de protección bajo tres escenarios de conservación distintos: un escenario pasado, que asumía que los esfuerzos recientes de adquisición de tierras nunca ocurrieron; un escenario actual, que asumía que no se protegen áreas adicionales a las ya conservadas; y un escenario deseado, que asumía que todas las áreas consideradas para ser protegidas son adquiridas eventualmente. Este método nos permitió cuantificar el progreso, en términos de la reducción del riesgo de extinción, en la protección de las especies obtenido por conservacionistas. También reveló el éxito limitado de los esfuerzos de adquisición de tierras en la disminución de los riesgos de extinción asociados con la pérdida de hábitat o con rangos geográficos pequeños. Se pronosticó que muchas especies de la Lake Wales Ridge permanecerán en alto riesgo aun si los esfuerzos de adquisición de tierra planificados son completamente exitosos. Al calcular los índices de protección con y sin cada sitio para todas las especies en peligro, también cuantificamos la contribución de cada área protegida a la conservación de cada especie, lo que permite que las decisiones de conservación se tomen en el contexto de una perspectiva mayor (global). El método del índice de protección se puede adaptar fácilmente a otros ecosistemas con múltiples especies raras y amenazadas. [source] Empirical comparison of density estimators for large carnivoresJOURNAL OF APPLIED ECOLOGY, Issue 1 2010Martyn E. Obbard Summary 1. Population density is a critical ecological parameter informing effective wildlife management and conservation decisions. Density is often estimated by dividing capture,recapture (C,R) estimates of abundance () by size of the study area, but this relies on the assumption of geographic closure , a situation rarely achieved in studies of large carnivores. For geographically open populations is overestimated relative to the size of the study area because animals with only part of their home range on the study area are available for capture. This bias (,edge effect') is more severe when animals such as large carnivores range widely. To compensate for edge effect, a boundary strip around the trap array is commonly included when estimating the effective trap area (). Various methods for estimating the width of the boundary strip are proposed, but / estimates of large carnivore density are generally mistrusted unless concurrent telemetry data are available to define. Remote sampling by cameras or hair snags may reduce study costs and duration, yet without telemetry data inflated density estimates remain problematic. 2. We evaluated recently developed spatially explicit capture,recapture (SECR) models using data from a common large carnivore, the American black bear Ursus americanus, obtained by remote sampling of 11 geographically open populations. These models permit direct estimation of population density from C,R data without assuming geographic closure. We compared estimates derived using this approach to those derived using conventional approaches that estimate density as /. 3. Spatially explicit C,R estimates were 20,200% lower than densities estimated as /. AICc supported individual heterogeneity in capture probabilities and home range sizes. Variable home range size could not be accounted for when estimating density as /. 4.Synthesis and applications. We conclude that the higher densities estimated as / compared to estimates from SECR models are consistent with positive bias due to edge effects in the former. Inflated density estimates could lead to management decisions placing threatened or endangered large carnivores at greater risk. Such decisions could be avoided by estimating density by SECR when bias due to geographic closure violation cannot be minimized by study design. [source] Winter selection of landscapes by woodland caribou: behavioural response to geographical gradients in habitat attributesJOURNAL OF APPLIED ECOLOGY, Issue 5 2008Daniel Fortin Summary 1Understanding animal,habitat relationships is central to the development of strategies for wildlife management and conservation. The availability of habitat attributes often changes along latitudinal and longitudinal axes, and animals may respond to those changes by adjusting their selection. We evaluated whether landscape selection by forest-dwelling woodland caribou Rangifer tarandus caribou varied along geographical gradients in habitat attributes. 2Centroids (n = 422) of track networks made by caribou in winter were recorded during aerial surveys conducted over 161 920 km2 of boreal forest in Québec, Canada. Autologistic models were estimated by comparing the characteristics of landscapes (201 km2) centred on each centroid to an equal number of randomly located landscapes, with an autocovariate controlling for the non-independence among caribou locations. 3The availability of habitat attributes varied along longitudinal and latitudinal gradients, and caribou altered their landscape selection with respect to those gradients. 4Information Theory provided substantial support for only one model. The model revealed that the probability of occurrence of caribou increased with the abundance of conifer forests over most of the study region, but this positive response gradually became negative towards the southern portion of the region. The association between caribou and lichens changed from being negative west of the study region to being positive in the eastern part. Availability of landscapes dominated by lichen decreased from west to east. Finally, caribou generally displayed an aversion to areas with high road density, a negative association that became positive in the southern part of the study region. 5Synthesis and applications. Under current legislation in Canada, the critical habitat of woodland caribou must be defined, and then protected. Our autoregressive models can help to identify landscapes to prioritize conservation efforts. The probability of occurrence of caribou was related to different landscape characteristics across their range, which implies that the typical habitat of woodland caribou differs spatially. Such behavioural plasticity could be problematic for defining critical habitat, but we showed that spatial variation in landscape selection was organized along geographical gradients. Our study illustrates how geographical trends in habitat selection can guide management and conservation decisions. [source] Current and historical factors influencing patterns of species richness and turnover of birds in the Gulf of Guinea highlandsJOURNAL OF BIOGEOGRAPHY, Issue 8 2005Catherine H. Graham Abstract Aim, The aims of this paper are to: examine how current and historical ecological factors affect patterns of species richness, endemism and turnover in the Gulf of Guinea highlands, test theoretical biogeographical predictions and provide information for making informed conservation decisions. Location, The Gulf of Guinea highlands in West Africa. Methods, We used multivariate and matrix regression models, and cluster analyses to assess the influence of current climate and current and historical isolation on patterns of richness and turnover for montane birds across the highlands. We examined three groups of birds: montane species (including widespread species), montane endemics and endemic subspecies. We applied a complementarity-based reserve selection algorithm using species richness with irreplaceability measures to identify areas of high conservation concern. Results, Environmental factors influenced richness for all groups of birds (species, endemic species and subspecies). Areas with high and consistent annual rainfall showed the highest species and endemic richness. Species clusters for all groups of birds generally differentiated three major montane regions, which are topographically isolated. Multiple mantel tests identified these same regions for endemic species and subspecies. The influence of historical isolation varied by species group; distributions of endemic montane species and subspecies were more associated with historical breaks than were all montane species, which included widespread non-endemic species. Main conclusions, Our analyses indicated important geographical structure amongst the bird assemblages in the highlands and, therefore, conservation prioritization should include mountains from within the geographical subregions identified in these analyses because these regions may harbour evolutionarily distinct populations of birds. [source] METHODS FOR JOINT INFERENCE FROM MULTIPLE DATA SOURCES FOR IMPROVED ESTIMATES OF POPULATION SIZE AND SURVIVAL RATESMARINE MAMMAL SCIENCE, Issue 3 2004Daniel Goodman Abstract Critical conservation decisions often hinge on estimates of population size, population growth rate, and survival rates, but as a practical matter it is difficult to obtain enough data to provide precise estimates. Here we discuss Bayesian methods for simultaneously drawing on the information content from multiple sorts of data to get as much precision as possible for the estimates. The basic idea is that an underlying population model can connect the various sorts of observations, so this can be elaborated into a joint likelihood function for joint estimation of the respective parameters. The potential for improved estimates derives from the potentially greater effective sample size of the aggregate of data, even though some of the data types may only bear directly on a subset of the parameters. The achieved improvement depends on specifics of the interactions among parameters in the underlying model, and on the actual content of the data. Assuming the respective data sets are unbiased, notwithstanding the fact that they may be noisy, we may gauge the average improvement in the estimates of the parameters of interest from the reduction, if any, in the standard deviations of their posterior marginal distributions. Prospective designs may be evaluated from analysis of simulated data. Here this approach is illustrated with an assessment of the potential value in various ways of merging mark-resight and carcass-survey data for the Florida manatee, as could be made possible by various modifications in the data collection protocols in both programs. [source] Evolutionary, behavioural and molecular ecology must meet to achieve long-term conservation goalsMOLECULAR ECOLOGY, Issue 18 2009J. SCOTT KEOGH Founder populations in reintroduction programmes can experience a genetic bottleneck simply because of their small size. The influence of reproductive skew brought on by polygynous or polyandrous mating systems in these populations can exacerbate already difficult conservation genetic problems, such as inbreeding depression and loss of adaptive potential. Without an understanding of reproductive skew in a target species, and the effect it can have on genetic diversity retained over generations, long-term conservation goals will be compromised. In this issue of Molecular Ecology, Miller et al. (2009a) test how founder group size and variance in male reproductive success influence the maintenance of genetic diversity following reintroduction on a long-term scale. They evaluated genetic diversity in two wild populations of the iconic New Zealand tuatara (Fig. 1), which differ greatly in population size and genetic diversity, and compared this to genetic diversity in multiple founder populations sourced from both populations. Population viability analysis on the maintenance of genetic diversity over 400 years (10 generations) demonstrated that while the loss of heterozygosity was low when compared with both source populations (1,14%), the greater the male reproductive skew, the greater the predicted losses of genetic diversity. Importantly however, the loss of genetic diversity was ameliorated after population size exceeded 250 animals, regardless of the level of reproductive skew. This study demonstrates that highly informed conservation decisions could be made when you build on a solid foundation of demographic, natural history and behavioural ecology data. These data, when informed by modern population and genetic analysis, mean that fundamental applied conservation questions (how many animals should make up a founder population?) can be answered accurately and with an eye to the long-term consequences of management decisions. Figure 1. ,Large adult male tuatara attacking a smaller male. Photo by Jeanine Refsnider. [source] Distinctiveness in the face of gene flow: hybridization between specialist and generalist gartersnakesMOLECULAR ECOLOGY, Issue 18 2008BENJAMIN M. FITZPATRICK Abstract Patterns of divergence and polymorphism across hybrid zones can provide important clues as to their origin and maintenance. Unimodal hybrid zones or hybrid swarms are composed predominantly of recombinant individuals whose genomes are patchworks of alleles derived from each parental lineage. In contrast, bimodal hybrid zones contain few identifiable hybrids; most individuals fall within distinct genetic clusters. Distinguishing between hybrid swarms and bimodal hybrid zones can be important for taxonomic and conservation decisions regarding the status and value of hybrid populations. In addition, the causes of bimodality are important in understanding the generation and maintenance of biological diversity. For example, are distinct clusters mostly reproductively isolated and co-adapted gene complexes, or can distinctiveness be maintained by a few ,genomic islands' despite rampant gene flow across much of the genome? Here we focus on three patterns of distinctiveness in the face of gene flow between gartersnake taxa in the Great Lakes region of North America. Bimodality, the persistence of distinct clusters of genotypes, requires strong barriers to gene flow and supports recognition of distinct specialist (Thamnophis butleri) and generalist (Thamnophis radix) taxa. Concordance of DNA-based clusters with morphometrics supports the hypothesis that trophic morphology is a key component of divergence. Finally, disparity in the level of differentiation across molecular markers (amplified fragment length polymorphisms) indicates that distinctiveness is maintained by strong selection on a few traits despite high gene flow currently or in the recent past. [source] Developing recovery and monitoring strategies for the endemic Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis) in ArizonaANIMAL CONSERVATION, Issue 1 2004Kate E. Buenau An important challenge in conservation biology is extracting pertinent information from the available data for endangered species. Rarely do we have enough information to precisely determine an organism's risk of extinction and other factors that affect its management. How, then, can we use limited information to make responsible conservation decisions on controversial species such as the Mount Graham red squirrel? We used several analytical approaches to examine 15 years of abundance data for the Mount Graham red squirrel in order to propose recovery criteria and to evaluate alternative conservation strategies. We analysed the historical population dynamics using a diffusion approximation model and showed that the main threat to the population was not the overall growth rate (which may well be greater than 1) but rather the wide range of variation in annual growth rates. We used information on the distribution of growth rates and abundance to classify the species as threatened under the Endangered Species Act (ESA). We then presented a simple demographic model to examine the effects of proportional changes in vital rates on the population growth rate (,). The elasticity values obtained for Mount Graham red squirrels indicate that the population is far more sensitive to changes in survival rates (particularly adult survival) compared to reproduction. Our analyses suggest that management should focus on refining monitoring techniques, reducing sources of variability, improving the survival of adult animals and filling the gaps in the currently available data. [source] | ||||||||||