232 research outputs found

    Evaluating the Potential Effectiveness of Compensatory Mitigation Strategies for Marine Bycatch

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    Conservationists are continually seeking new strategies to reverse population declines and safeguard against species extinctions. Here we evaluate the potential efficacy of a recently proposed approach to offset a major anthropogenic threat to many marine vertebrates: incidental bycatch in commercial fisheries operations. This new approach, compensatory mitigation for marine bycatch (CMMB), is conceived as a way to replace or reduce mandated restrictions on fishing activities with compensatory activities (e.g., removal of introduced predators from islands) funded by levies placed on fishers. While efforts are underway to bring CMMB into policy discussions, to date there has not been a detailed evaluation of CMMB's potential as a conservation tool, and in particular, a list of necessary and sufficient criteria that CMMB must meet to be an effective conservation strategy. Here we present a list of criteria to assess CMMB that are tied to critical ecological aspects of the species targeted for conservation, the range of possible mitigation activities, and the multi-species impact of fisheries bycatch. We conclude that, overall, CMMB has little potential for benefit and a substantial potential for harm if implemented to solve most fisheries bycatch problems. In particular, CMMB is likely to be effective only when applied to short-lived and highly-fecund species (not the characteristics of most bycatch-impacted species) and to fisheries that take few non-target species, and especially few non-seabird species (not the characteristics of most fisheries). Thus, CMMB appears to have limited application and should only be implemented after rigorous appraisal on a case-specific basis; otherwise it has the potential to accelerate declines of marine species currently threatened by fisheries bycatch

    Multi-scale effects of nestling diet on breeding performance in a terrestrial top predator inferred from stable isotope analysis

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    This is the final version of the article. Available from the publisher via the DOI in this record.Inter-individual diet variation within populations is likely to have important ecological and evolutionary implications. The diet-fitness relationships at the individual level and the emerging population processes are, however, poorly understood for most avian predators inhabiting complex terrestrial ecosystems. In this study, we use an isotopic approach to assess the trophic ecology of nestlings in a long-lived raptor, the Bonelli's eagle Aquila fasciata, and investigate whether nestling dietary breath and main prey consumption can affect the species' reproductive performance at two spatial scales: territories within populations and populations over a large geographic area. At the territory level, those breeding pairs whose nestlings consumed similar diets to the overall population (i.e. moderate consumption of preferred prey, but complemented by alternative prey categories) or those disproportionally consuming preferred prey were more likely to fledge two chicks. An increase in the diet diversity, however, related negatively with productivity. The age and replacements of breeding pair members had also an influence on productivity, with more fledglings associated to adult pairs with few replacements, as expected in long-lived species. At the population level, mean productivity was higher in those population-years with lower dietary breadth and higher diet similarity among territories, which was related to an overall higher consumption of preferred prey. Thus, we revealed a correspondence in diet-fitness relationships at two spatial scales: territories and populations. We suggest that stable isotope analyses may be a powerful tool to monitor the diet of terrestrial avian predators on large spatio-temporal scales, which could serve to detect potential changes in the availability of those prey on which predators depend for breeding. We encourage ecologists and evolutionary and conservation biologists concerned with the multi-scale fitness consequences of inter-individual variation in resource use to employ similar stable isotope-based approaches, which can be successfully applied to complex ecosystems such as the Mediterranean.Funding for this work was provided by projects CGL2007-64805 and CGL2010-17056 from the ‘‘Ministerio de Ciencia e Innovacio´n, Gobierno de Espan˜ a’’, the ‘‘A`rea d’Espais Naturals de la Diputacio´ de Barcelona’’, and Miquel Torres S.A. Fieldwork in France was carried out within the framework of the second National Action Plan for Bonelli’s eagle from the ‘‘Ministe`re franc¸ais de l’E´cologie, de L’E´nergie, du De´veloppement Durable et de la Mer’’ and coordinated by the DREAL LR ‘‘Direction Re´gionale de l’Environnement, de l’Ame´nagement et du Logement-Languedoc-Roussillon’’. J. Resano-Mayor was supported by a predoctoral grant from the ‘‘Departamento de Educacio´n, Gobierno de Navarra; Plan de Formacio´n y de I+D 2008–2009’’, and M. Moleo´n by a postdoctoral grant from the ‘‘Ministerio de Educacio´n, Gobierno de Espan˜ a; Plan Nacional de I+D+i 2008–2011’’. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Aging and Health

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    Aging is a major risk factor for chronic diseases, which in turn can provide information about the aging of a biological system. This publication serves as an introduction to systems biology and its application to biological aging. Key pathways and processes that impinge on aging are reviewed, and how they contribute to health and disease during aging is discussed. The evolution of this situation is analyzed, and the consequences for the study of genetic effects on aging are presented. Epigenetic programming of aging, as a continuation of development, creates an interface between the genome and the environment. New research into the gut microbiome describes how this interface may operate in practice with marked consequences for a variety of disorders. This analysis is bolstered by a view of the aging organism as a whole, with conclusions about the mechanisms underlying resilience of the organism to change, and is expanded with a discussion of circadian rhythms in aging

    Population viability and conservation strategies for the Eurasian Black Vulture (Aegypius monachus) in Southeast Europe

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    The Eurasian Black Vulture is a globally threatened raptor that in Southeast Europe only occurs in an isolated population in Greece. We examined the population viability for the species under demographic fluctuations and conservation scenarios. The current population showed no possibility of extinction for the next 100 years. However, simulated scenarios showed that the most important factor affecting the viability of the species was medium and high poisoning, leading to 94.8% and 100% probability of extinction, respectively. Furthermore, high reduction of supplementary feeding highlighted an 18.6% extinction possibility. Also, a high increase of wind farms in the area may result in 17.4% extinction possibility. Additionally, the non-establishment of the feeding station in 1987 in the study area would have resulted in an extinction risk of 7%. The species can be translocated to the Olympus National Park by releasing 80 juveniles over 10 years. The implementation of the conservation scenarios concerning the establishment of a supplementary feeding site network, and the reintroduction of the Eurasian Black Vulture in its historic range, along with the elimination of threats posed by poisoning, low food availability, and wind farms would increase the probability of the species persistence and allow the population to become a source for dispersal across Southeast Europe

    Ecological Drivers of Brown Pelican Movement Patterns and Reproductive Success in the Gulf of Mexico

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    The effects of environmental change on vast, inaccessible marine ecosystems are often difficult to measure and detect. As accessible and highly visible apex predators in marine environments, seabirds are often selected as indicators for studying the effects of disturbance at lower trophic levels, although data are restricted both temporally and spatially. For example, studies of seabirds have historically been limited to the breeding season, with limited data being available throughout the remainder of the annual cycle. Additionally, understanding of habitat associations and behavior of seabirds in the marine environment comes primarily from pelagic seabirds, whose habitat year-round is generally in remote marine areas removed from anthropogenic development, while similar data from nearshore seabirds are less common. Such data gaps limit our understanding or life-history traits among seabirds, one of the most imperiled avian groups globally, and subsequently our ability to inform conservation and marine spatial planning. My goal was to examine ecological relationships of diet, breeding biology, and movement patterns of a nearshore tropical seabird, the Eastern brown pelican, in the Gulf of Mexico, one of the most anthropogenically developed marine ecosystems worldwide. While my results supported previous findings that nutritional conditions are a key driver of seabird reproductive success and recruitment, they differ in suggesting that prey availability and delivery rates are more important to reproductive rates than energetic value of prey species. Since direct measurement of reproductive rates is time-consuming and difficult to collect, I also tested an integrated measure of nutritional stress during development, feather corticosterone, as a predictor of nestling survival and fledging rates. Corticosterone predicted 94% of inter-colony variation in fledging success and was also correlated with post-fledging survival, making it a powerful tool for measuring demographic patterns in this species. To measure adult movement patterns, I deployed bird-borne biologgers to collect highly accurate spatial data from pelicans throughout the annual cycle. I found that individual breeders quickly returned to normal behavior after capture and tagging. GPS tracking also indicated that pelicans were highly mobile, ranging over large areas during the breeding season and migrating up to 2,500 kilometers during non-breeding. Movement patterns were influenced by local conspecific competition during both breeding and migration, such that birds from larger colonies moved longer distances year-round compared to those from smaller colonies. I also found a high degree of spatial, temporal, and individual variation in exposure to surface pollutants across the population. I recorded a high degree of individual variation in movement, which interacted with pollutant exposure to create a complex and varying distribution of risk throughout the northern Gulf metapopulation of brown pelicans. Understanding the factors driving this variation will inform future monitoring, conservation, and mitigation efforts for this species

    Assessing the cumulative impacts of wind farms on birds

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    As governments pledge to combat climate change, wind turbines are becoming a common feature of terrestrial and marine environments. Although wind power is a renewable energy source and a means of reducing carbon emissions, there is a need to ensure that the wind farms themselves do not damage the environment. There is particular concern over the impacts of wind farms on bird populations. In this thesis I have explored how to assess the cumulative impacts of wind farms on birds. Cumulative impact assessment is a legislative requirement of environmental impact assessment but too frequently it has been tacked on to the end of assessments as an afterthought. Reasons for this are numerous but a recurring theme is the lack of clear definitions and guidance on how to perform cumulative assessments. Therefore I developed a conceptual framework to promote transparency. The core concept is that explicit definitions of impacts, actions and scales of assessment are required to reduce uncertainty in the process of assessment and improve communication between stakeholders. Only when it is clear what has been included within a cumulative assessment, is it possible to start to make comparisons between developments. I also recommend a more strategic approach to cumulative impact assessment. If birds avoid wind farms then the structures act as barriers to movement and birds must fly further to reach their destination. If the additional distance has an associated energetic cost then this will impact an individual. With data collected using surveillance radar, I investigated the impact of the Nysted offshore wind farm on a population of common eider Somateria mollissima migrating from Finland to the Wadden Sea. The impacts of the wind farm appeared trivial and it required 100 equivalent wind farms before a significant impact was detected. Using the same radar data I also constructed a model to quantify the movement process of birds in response to wind turbines and therefore provide wind farm developers with a useful tool to predict the impacts of different wind farm designs. The impacts of wind farms may be greater for birds that interact with the turbines on a daily basis than for migrating individuals. Using an energetic modelling approach I explored the impact for a suite of breeding seabirds commuting past a wind farm between their breeding and feeding areas. Impacts of flying increasing distances associated with increasing numbers of wind turbines were species-specific and costs were highest for species with high wing loadings and high daily frequency of foraging flights. However, costs of extra flight to avoid a wind farm appear much less than those imposed by low food abundance or adverse weather conditions. Finally, a spatially-explicit individual-based model was developed to assess cumulative impacts of wind turbines through collision mortality and direct and indirect habitat loss, on a population of hen harriers Circus cyaneus on Orkney. Increasing numbers of wind turbines caused declines in the hen harrier population but the population response varied according to where turbines were located. Therefore, although wind turbines impact hen harriers, it may be possible to reduce the effects by considering hen harrier ecology during the planning procedure and/or implementing mitigating measures such as rough grassland restoration in strategic locations away from turbines

    Conservation Implications of Illegal Bird Trade and Disease Risk in Peru

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    Trade in wild-caught animals as pets is a global conservation and animal-welfare concern. Illegal and poorly-regulated legal wildlife trade can threaten biodiversity, spread infectious diseases, and result in considerable animal suffering and mortality. I used illegal wildlife trade in Peru, specifically native bird trade, as a case study to explore important aspects and consequences of the trade for domestic markets. With data collected from a five-year market survey and governmental seizure records, I applied a statistical modeling approach to investigate the influence of Peru’s legal export quota system on the country’s illegal domestic bird trade. I used an infectious-disease mathematical modeling approach to analyze how illegal harvest influenced disease dynamics in a wild parrot population. Finally, I used qualitative research methods to investigate the role of non-governmental organizations (NGOs) and their members’ philosophical perspectives toward wildlife in combating illegal trade. I found that Peru had a thriving illegal trade in native birds (mostly parrots) for domestic consumers; 150 species were recorded in markets and/or seizures with over 35,250 individuals offered for sale (2007–2011). Peru’s current legal export quota system did not influence avian abundance in markets, but historic export trade did. Because authorities frequently release confiscated birds without health evaluation, infectious pathogens may be introduced into wild populations. I determined that the hypothetical release of white-winged parakeets infected with Newcastle disease would provoke a disease outbreak with considerable mortality in a susceptible population. Higher rates of illegal harvest dampened the magnitude of the outbreak, but the combined effects of high harvest and disease-induced mortality may threaten population survival. According to interviewees, Peru’s government was considered lax in combating illegal wildlife trade and as such, many NGOs supplemented the government’s efforts. The five NGOs most dedicated to decreasing illegal wildlife-pet trade in Peru had strong, dual philosophical perspectives that prioritized both wildlife populations and individual wild animals. In conclusion, there is considerable avian trafficking for Peru’s domestic consumers that (1) is independent of Peru’s export market, (2) provides a mechanism to introduce harmful infectious diseases into wild population, and (3) is combated most by dual-perspective NGOs
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