Gilman E.,Hawaii Pacific University |
Chaloupka M.,University of Queensland |
Read A.,Duke University |
Dalzell P.,Western Pacific Regional Fishery Management Council |
And 2 more authors.
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2012
Declines in absolute abundance and altered size distributions from size-selective removals of market species of pelagic apex predators in tuna fisheries alters evolutionary characteristics of populations and ecosystem processes and stability. Pelagic fishing at seamounts, where hyperstability of pelagic predators may occur, can exacerbate declining abundance and have high bycatch of species groups that are highly vulnerable to overexploitation. Generalized additive mixed Poisson regression models (GAMMs) were fitted to Hawaii longline tuna fishery observer data to determine temporal trends in standardized catch rates, an index for local, relative abundance. Temporal trends in expectile length distributions were determined through geoadditive expectile GAMMs. Significant declining trends in relative abundance in this fishery were observed for tunas, sharks and billfish. A decline in seabird standardized catch rate occurred concurrently with the uptake of seabird bycatch mitigation technology. Changed spatial distribution of fishing effort and increased use of wider circle hooks likely contributed to a declining sea turtle standardized catch rate. Tuna and billfish mean lengths significantly increased over the time series due to entire distributions of length classes having shifted towards larger fish. Larger tunas comprised a larger proportion of the catch due to fewer small tunas being caught, and to a lesser extent because mean lengths of larger size classes increased. Conversely, billfish largest length classes experienced the largest increases in average lengths. Changes in spatial and seasonal distributions of fishing effort, increased use of wider circle hooks, and possibly increasing purse seine selective removals of juvenile tunas, may have contributed to increased selectivity for larger fish. Significant differences in standardized catch rates and length distributions at a shallow seamount vs. the open ocean confirms the aggregating effect of seamounts on pelagic predators, including juvenile market species of pelagic fish and species groups relatively vulnerable to overexploitation. Wider circle hooks significantly improved valuable tuna standardized catch rates, but also increased unwanted shark and reduced valuable billfish standardized catch rates. © 2012 John Wiley & Sons, Ltd..
Godefroid S.,National Botanic Garden of Belgium |
Godefroid S.,Vrije Universiteit Brussel |
Godefroid S.,Roosevelt University |
Piazza C.,Conservatoire botanique national de Corse |
And 18 more authors.
Biological Conservation | Year: 2011
Reintroduction of native species has become increasingly important in conservation worldwide for recovery of rare species and restoration purposes. However, few studies have reported the outcome of reintroduction efforts in plant species. Using data from the literature combined with a questionnaire survey, this paper analyses 249 plant species reintroductions worldwide by assessing the methods used and the results obtained from these reintroduction experiments. The objectives were: (1) to examine how successful plant species reintroductions have been so far in establishing or significantly augmenting viable, self-sustaining populations in nature; (2) to determine the conditions under which we might expect plant species reintroductions to be most successful; (3) to make the results of this survey available for future plant reintroduction trials. Results indicate that survival, flowering and fruiting rates of reintroduced plants are generally quite low (on average 52%, 19% and 16%, respectively). Furthermore, our results show a success rate decline in individual experiments with time. Survival rates reported in the literature are also much higher (78% on average) than those mentioned by survey participants (33% on average). We identified various parameters that positively influence plant reintroduction outcomes, e.g., working in protected sites, using seedlings, increasing the number of reintroduced individuals, mixing material from diverse populations, using transplants from stable source populations, site preparation or management effort and knowledge of the genetic variation of the target species. This study also revealed shortcomings of common experimental designs that greatly limit the interpretation of plant reintroduction studies: (1) insufficient monitoring following reintroduction (usually ceasing after 4 years); (2) inadequate documentation, which is especially acute for reintroductions that are regarded as failures; (3) lack of understanding of the underlying reasons for decline in existing plant populations; (4) overly optimistic evaluation of success based on short-term results; and (5) poorly defined success criteria for reintroduction projects. We therefore conclude that the value of plant reintroductions as a conservation tool could be improved by: (1) an increased focus on species biology; (2) using a higher number of transplants (preferring seedlings rather than seeds); (3) taking better account of seed production and recruitment when assessing the success of reintroductions; (4) a consistent long-term monitoring after reintroduction. © 2010 Elsevier Ltd.
Holetschek J.,Botanic Garden and Botanical Museum Berlin Dahlem |
Droge G.,Botanic Garden and Botanical Museum Berlin Dahlem |
Guntsch A.,Botanic Garden and Botanical Museum Berlin Dahlem |
Berendsohn W.G.,Botanic Garden and Botanical Museum Berlin Dahlem
Plant Biosystems | Year: 2012
Within the context of the Global Biodiversity Information Facility (GBIF), the Biological Collections Access Service (BioCASe) has been set up to foment data provision by natural history content providers. Products include the BioCASe Protocol and the PyWrapper software, a web service allowing to access rich natural history data using complex schemas like ABCD (Access to Biological Collection Data). New developments include the possibility to produce DarwinCore-Archive files using PyWrapper, in order to facilitate the indexing of large datasets by aggregators such as GBIF. However, BioCASe continues to be committed to distributed data access and continues to provide the possibility to directly query the web service for up-to-date data directly from the provider's database. ABCD provides comprehensive coverage of natural history data, and has been extended to cover DNA collections (ABCD-DNA) and geosciences (ABCD-EFG, the extension for geosciences). BioCASe also developed web portal software that allows to access and display rich data provided by special interest networks. We posit that the XML-based networking approach using a highly standardised data definition such as ABCD continues to be a valuable approach towards mobilising natural history information. Some suggestions are made regarding further improvements of ABCD. © 2012 Copyright Taylor and Francis Group, LLC.