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Species Recovery (species + recovery)
Selected AbstractsReducing threats to species: threat reversibility and links to industryCONSERVATION LETTERS, Issue 4 2010Laura R. Prugh Abstract Threats to species' persistence are typically mitigated via lengthy and costly recovery planning processes that are implemented only after species are at risk of extinction. To reduce overall threats and minimize risks to species not yet imperiled, a proactive and broad-scale framework is needed. Using data on threats to imperiled species in Canada to illustrate our approach, we link threats to industries causing the harm, thus providing regulators with quantitative data that can be used directly in cost-benefit and risk analyses to broadly reduce threat levels. We then show how ranking the ease of threat abatement and reversal assists prioritization by identifying threats that are easiest to mitigate as well as threats that are possible to abate but nearly impossible to reverse. This new framework increases the usefulness of widely available threat data for preventative conservation and species recovery. [source] Priorities and paradigms: directions in threatened species recoveryCONSERVATION LETTERS, Issue 3 2009Sue V. Briggs Abstract Recovering threatened species is a key challenge for conservation managers, policy makers, and researchers. This article describes a practical framework for assigning priorities for recovery of threatened species according to cost-effectiveness of recovery strategies for species groups. The framework has the following steps: (1) determine the conservation goal,persistence in the wild of the largest number of threatened species with the funds available; (2) assign threatened species to species recovery groups according to their characteristics and threats,small-population species that require actions at sites and declining-population species that require actions across landscapes; (3) identify the recovery strategies and their component actions for the species groups; (4) cost the recovery strategies for the species groups; (5) determine the cost-effectiveness of the recovery strategies for the species groups,the number of species recovered divided by the cost of the strategies; (6) assign priorities to the recovery strategies according to their cost-effectiveness; (7) allocate funds to the recovery strategies that maximize the number of threatened species recovered for the funds available; and (8) undertake the funded recovery strategies and actions. The framework is illustrated with an example. [source] The future of stock enhancements: lessons for hatchery practice from conservation biologyFISH AND FISHERIES, Issue 2 2002Culum Brown Abstract The world's fish species are under threat from habitat degradation and over-exploitation. In many instances, attempts to bolster stocks have been made by rearing fish in hatcheries and releasing them into the wild. Fisheries restocking programmes have primarily headed these attempts. However, a substantial number of endangered species recovery programmes also rely on the release of hatchery-reared individuals to ensure long-term population viability. Fisheries scientists have known about the behavioural deficits displayed by hatchery-reared fish and the resultant poor survival rates in the wild for over a century. Whilst there remain considerable gaps in our knowledge about the exact causes of post-release mortality, or their relative contributions, it is clear that significant improvements could be made by rethinking the ways in which hatchery fish are reared, prepared for release and eventually liberated. We emphasize that the focus of fisheries research must now shift from husbandry to improving post-release behavioural performance. In this paper we take a leaf out of the conservation biology literature, paying particular attention to the recent developments in reintroduction biology. Conservation reintroduction techniques including environmental enrichment, life-skills training, and soft release protocols are reviewed and we reflect on their application to fisheries restocking programmes. It emerges that many of the methods examined could be implemented by hatcheries with relative ease and could potentially provide large increases in the probability of survival of hatchery-reared fish. Several of the necessary measures need not be time-consuming or expensive and many could be applied at the hatchery level without any further experimentation. [source] Population size, weight distribution and food in a persistent population of the rare medicinal leech, Hirudo medicinalisFRESHWATER BIOLOGY, Issue 8 2008J. M. ELLIOTT Summary 1. It is important for species recovery and conservation management projects to know the minimum viable population size for rare and endangered species, such as the medicinal leech, Hirudo medicinalis. Therefore, using a catch-removal method, this study estimated every two years (1986, 1988, 1990, 1992) the total number of medicinal leeches in a tarn in the English Lake District, and the number of mature adults in the population. 2. Four samples were taken each year in June and July, when water temperatures exceeded 20 °C. Population size was estimated both by maximum likelihood and regression methods. All leeches were weighed alive and size groups were separated by polymodal frequency analysis. A small sample of the blood meal in each leech gut was taken before the leeches were returned to the tarn, and was used to estimate the proportion of mammalian and non-mammalian blood in the meals. 3. Both methods of estimation produced similar values, increasing confidence in the population estimates. Values for the total population in June and July varied among years from 248 to 288, the maximum value being only 16% higher than the minimum. Values for the number of mature leeches varied from 48 to 58 (19,20% of the total population), and this was an estimate of the effective population size. 4. There were four size groups. The largest mature leeches (live weight >5 g) in group IV formed only 1% of the population, and the smallest (0.02,0.5 g) in group I 14,17%. Most leeches were in two overlapping groups of immature (64,67% of population) and mature (18%) leeches with size ranges of 0.4,3.4 g and 2.5,5 g respectively. The percentage of leeches in each size group was very consistent among years. Blood meals were found in 38,44% of the leeches in group I, 45,50% in group II, 70,75% in group III, and 100% in group IV, but mammalian blood was present only in larger mature leeches (>3.5 g). 5. Medicinal leeches were first detected in the tarn in 1980 and are still present in 2007, so the population has persisted for at least 27 years. Compared with minimum viable population sizes for other species, including many endangered species, values for this medicinal leech population are extremely low, but may be typical of some rare freshwater invertebrates in isolated habitats. [source] The ED strategy: how species-level surrogates indicate general biodiversity patterns through an ,environmental diversity' perspectiveJOURNAL OF BIOGEOGRAPHY, Issue 8 2004D. P. Faith Abstract Biodiversity assessment requires that we use surrogate information in practice to indicate more general biodiversity patterns. ,ED' refers to a surrogates framework that can link species data and environmental information based on a robust relationship of compositional dissimilarities to ordinations that indicate underlying environmental variation. In an example analysis of species and environmental data from Panama, the environmental and spatial variables that correlate with an hybrid multi-dimensional scaling ordination were able to explain 83% of the variation in the corresponding Bray Curtis dissimilarities. The assumptions of ED also provide the rationale for its use of p-median optimization criteria to measure biodiversity patterns among sites in a region. M.B. Araújo, P.J. Densham & P.H. Williams (2004, Journal of Biogeography31, 1) have re-named ED as ,AD' in their evaluation of the surrogacy value of ED based on European species data. Because lessons from previous work on ED options consequently may have been neglected, we use a corroboration framework to investigate the evidence and ,background knowledge' presented in their evaluations of ED. Investigations focus on the possibility that their weak corroboration of ED surrogacy (non-significance of target species recovery relative to a null model) may be a consequence of Araújo et al.'s use of particular evidence and randomizations. We illustrate how their use of discrete ED, and not the recommended continuous ED, may have produced unnecessarily poor species recovery values. Further, possible poor optimization of their MDS ordinations, due to small numbers of simulations and/or low resolution of stress values appears to have provided a possible poor basis for ED application and, consequently, may have unnecessarily favoured non-corroboration results. Consideration of Araújo et al.'s randomizations suggests that acknowledged sampling biases in the European data have not only artefactually promoted the non-significance of ED recovery values, but also artefactually elevated the significance of competing species surrogates recovery values. We conclude that little credence should be given to the comparisons of ED and species-based complementarity sets presented in M.B. Araújo, P.J. Densham & P.H. Williams (2004, Journal of Biogeography31, 1), unless the factors outlined here can be analysed for their effects on results. We discuss the lessons concerning surrogates evaluation emerging from our investigations, calling for better provision in such studies of the background information that can allow (i) critical examination of evidence (both at the initial corroboration and re-evaluation stages), and (ii) greater synthesis of lessons about the pitfalls of different forms of evidence in different contexts. [source] Variation in the impact of exotic grasses on native plant composition in relation to fire across an elevation gradient in HawaiiAUSTRAL ECOLOGY, Issue 5 2000Carla M. D'Antonio Abstract The impact that an exotic species can have on the composition of the community it enters is a function of its abundance, its particular species traits and characteristics of the recipient community. In this study we examined species composition in 14 sites burned in fires fuelled by non-indigenous C4 grasses in Hawaii Volcanoes National Park, Hawaii. We considered fire intensity, time since fire, climatic zone of site, unburned grass cover, unburned native cover and identity of the most abundant exotic grass in the adjacent unburned site as potential predictor variables of the impact of fire upon native species. We found that climatic zone was the single best variable for explaining variation in native cover among burned sites and between burned and unburned pairs. Fire in the eastern coastal lowlands had a very small effect on native plant cover and often stimulated native species regeneration, whereas fire in the seasonal submontane zone consistently caused a decline in native species cover and almost no species were fire tolerant. The dominant shrub, Styphelia tameiameia, in particular was fire intolerant. The number of years since fire, fire intensity and native cover in reference sites were not significantly correlated with native species cover in burned sites. The particular species of grass that carried the fire did however, have a significant effect on native species recovery. Where the African grass Melinis minutiflora was a dominant or codominant species, fire impacts were more severe than where it was absent regardless of climate zone. Overall, the impacts of exotic grass-fuelled fires on native species composition and cover in seasonally dry Hawaiian ecosystems was context specific. This specificity is best explained by differences between the climatic zones in which fire occurred. Elevation was the main physical variable that differed among the climatic zones and it alone could explain a large percentage of the variation in native cover among sites. Rainfall, by contrast, did not vary systematically with elevation. Elevation is associated with differences in composition of the native species assemblages. In the coastal lowlands, the native grass Heteropogon contortus, was largely responsible for positive changes in native cover after fire although other native species also increased. Like the exotic grasses, this species is a perennial C4 grass. It is lacking in the submontane zone and there are no comparable native species there and almost all native species in the submontane zone were reduced by fire. The lack of fire tolerant species in the submontane zone thus clearly contributes to the devastating impact of fire upon native cover there. [source] Biology, ecology and status of Iberian ibex Capra pyrenaica: a critical review and research prospectusMAMMAL REVIEW, Issue 1 2009PELAYO ACEVEDO ABSTRACT 1The Iberian ibex Capra pyrenaica is endemic to the Iberian Peninsula and of the four subspecies originally recognized, recent extinctions mean that only two now persist. Recent genetic analyses have cast doubt on the generally accepted taxonomy of the species, where four subspecies were distinguished by coat colour and horn morphology, and propose the distinction of two subspecies based on their mitochondrial DNA sequence polymorphism. These analyses make clear the need for a comprehensive revision that integrates genetic and morphological approaches resulting in a definitive description and differentiation of the subspecies. 2Studies of ibex behavioural ecology and health status are scarce and generally descriptive. They should be implemented in an integrative way, taking into account the ecological requirements of the species, current population status, the presence of other sympatric wild and domestic ungulates, and the type of hunting regime and management in their distribution areas. 3A natural expansion of the species is currently taking place. Ibexes are present and well established in all the main mountain ranges of the Spanish Iberian Peninsula, and have recently expanded their range into the north of Portugal. Other authors estimated a total population of more than 50 000 individuals 10 years ago, distributed over more than 60 000 km2, with an average population density of 2.7 ibex/km2. However, these estimates were obtained prior to the species' recovery from recent epizootics of sarcoptic mange and should be updated. Survey methods, mainly direct count-based methods, should be adjusted to suit mountainous conditions, where it is difficult to estimate accurately the surveyed surface. 4A series of threats to ibex conservation have been identified, such as population overabundance, disease prevalence and potential competition with domestic livestock and invasive ungulates, along with negative effects of human disturbance through tourism and hunting. 5Applied ecological issues focused on the proper management of populations should be prioritized, along with the identification of current threats based on empirical, ecological data obtained from populations living in various ecological conditions in different regions. [source] Inbreeding depression and founder diversity among captive and free-living populations of the endangered pink pigeon Columba mayeriANIMAL CONSERVATION, Issue 4 2004Kirsty J. Swinnerton The endemic pink pigeon has recovered from less than 20 birds in the mid-1970s to 355 free-living individuals in 2003. A major concern for the species' recovery has been the potential genetic problem of inbreeding. Captive pink pigeons bred for reintroduction were managed to maximise founder representation and minimise inbreeding. In this paper, we quantify the effect of inbreeding on survival and reproductive parameters in captive and wild populations and quantify DNA sequence variation in the mitochondrial d-loop region for pink pigeon founders. Inbreeding affected egg fertility, squab, juvenile and adult survival, but effects were strongest in highly inbred birds (F,0.25). Inbreeding depression was more apparent in free-living birds where even moderate levels of inbreeding affected survival, although highly inbred birds were equally compromised in both captive and wild populations. Mitochondrial DNA haplotypic diversity in pink pigeon founders is low, suggesting that background inbreeding is contributing to low fertility and depressed productivity in this species, as well as comparable survival of some groups of non-inbred and nominally inbred birds. Management of wild populations has boosted population growth and may be required long-term to offset the negative effects of inbreeding depression and enhance the species' survival. [source] | ||||||||||||||||||||||