Guillemain M.,Office National de la Chasse et de la Faune Sauvage |
Devineau O.,Fundacion Charles Darwin |
Hearn R.,Wildfowl and Wetlands Trust |
King R.,Wildfowl and Wetlands Trust |
Grantham M.,British Trust for Ornithology
Journal of Ornithology | Year: 2011
Although knowledge of ring recovery rate is of crucial importance to establish demographic parameters, such as survival probability, this information is generally unknown for the dabbling ducks. The almost single existing value from the North American Mallard (Anas platyrhynchos) is thus generally applied to other species or geographic areas, even though this assumption may be strongly misleading. In the study reported here, we have relied on a proxy for actual ring recovery rate, namely, the proportion of rings fitted each year that were eventually reported, to test for differences between duck species (Mallard and Teal Anas crecca) and between countries [England (UK) and France] for Teal. Potential trends over time (1952-2005) were also assessed. Ring recovery rate was found to have sharply decreased and at a similar rate over time in both species in France, and in both countries for Teal (e. g. from 22. 7% in 1952 to 7. 2% in 1992 for the British Teal). Teal rings were, however, reported more frequently than Mallard ones, and Teal rings were more frequently reported in the UK than in France. In recent years, a phone number for reporting the information has been included on the bird mark, with the immediate result of a doubling in the recovery rate in France. Adaptations to current ringing procedures that would improve ring reporting would appear to be necessary in the future if researchers are to keep ringing as a valuable source of information for bird demography studies. © 2010 Dt. Ornithologen-Gesellschaft e.V.
Van Driesche R.G.,University of Massachusetts Amherst |
Carruthers R.I.,U.S. Department of Agriculture |
Center T.,U.S. Department of Agriculture |
Hoddle M.S.,University of California at Riverside |
And 44 more authors.
Biological Control | Year: 2010
Of the 70 cases of classical biological control for the protection of nature found in our review, there were fewer projects against insect targets (21) than against invasive plants (49), in part, because many insect biological control projects were carried out against agricultural pests, while nearly all projects against plants targeted invasive plants in natural ecosystems. Of 21 insect projects, 81% (17) provided benefits to protection of biodiversity, while 48% (10) protected products harvested from natural systems, and 5% (1) preserved ecosystem services, with many projects contributing to more than one goal. In contrast, of the 49 projects against invasive plants, 98% (48) provided benefits to protection of biodiversity, while 47% (23) protected products, and 25% (12) preserved ecosystem services, again with many projects contributing to several goals. We classified projects into complete control (pest generally no longer important), partial control (control in some areas but not others), and " in progress," for projects in development for which outcomes do not yet exist. For insects, of the 21 projects discussed, 62% (13) achieved complete control of the target pest, 19% (4) provided partial control, and 43% (9) are still in progress. By comparison, of the 49 invasive plant projects considered, 27% (13) achieved complete control, while 33% (16) provided partial control, and 49% (24) are still in progress. For both categories of pests, some projects' success ratings were scored twice when results varied by region. We found approximately twice as many projects directed against invasive plants than insects and that protection of biodiversity was the most frequent benefit of both insect and plant projects. Ecosystem service protection was provided in the fewest cases by either insect or plant biological control agents, but was more likely to be provided by projects directed against invasive plants, likely because of the strong effects plants exert on landscapes. Rates of complete success appeared to be higher for insect than plant targets (62% vs 27%), perhaps because most often herbivores gradually weaken, rather than outright kill, their hosts, which is not the case for natural enemies directed against pest insects. For both insect and plant biological control, nearly half of all projects reviewed were listed as currently in progress, suggesting that the use of biological control for the protection of wildlands is currently very active. © 2010 Elsevier Inc.
Feeding habits of two pelagic fish thunnus albacares and Acanthocybium solandri from the galapagos marine reserve [Hábitos alimentarios de dos peces pelágicos thunnus albacares y Acanthocybium solandri de la reserva marina de galápagos]
Baque-Menoscal J.,Fundacion Charles Darwin |
Paez-Rosas D.,Secretaria Nacional de Educacion Superior |
Paez-Rosas D.,San Francisco de Quito University |
Paez-Rosas D.,National Polytechnic Institute of Mexico |
And 2 more authors.
Revista de Biologia Marina y Oceanografia | Year: 2012
This study analyzed the trophic niche of two pelagic species that inhabit the Galapagos Marine Reserve, with the aim of understanding the interactions between these predators and other species. From June to October of 2009, 238 stomachs of Thunnus albacares and 151 of Acanthocybium solandri were analyzed from 4 specific sites of the Archipelago. Prey diversity reached an asymptotic level at 11 and 100 stomachs respectively. A total of 28 prey were found in T. albacores, in which the Humboldt squid Dosidicus gigas (36.68%) was the numerically most represented, whereas 11 prey were found in A. solandri in which the flying fish Prognichthys tringa and D. gigas were the two main prey items representing 40% of the diet. In terms of weight and frequency of occurrence, the most important prey were the squids Histioteuthis heteropsis (8.75%) and D. gigas (63.41%) for T. albacares and Trachurus sp. (19.86%) and Prognichthys tringa (1.19%) for A. solandri. The index of relative importance (IIR) confirmed the importance of these items in the diet of both predators. The trophic breadth level classifies T. albacares as a specialist - and A. solandri as a generalist predator (Levin = 0.17 and 0.65, respectively). These results suggest important differences in feeding habits in the two apparently sympatric species, which allows them to minimize interactions between species and to maintain their sympatric presence in this region.
Devineau O.,Center dEcologie Fonctionnelle et Evolutive |
Guillemain M.,Office National de la Chasse et de la Faune Sauvage |
Johnson A.R.,Tour du Valat |
Lebreton J.-D.,Fundacion Charles Darwin
Wildlife Biology | Year: 2010
The impact of waterfowl harvest on the dynamics of duck populations remains incompletely understood. While wide-scale monitoring and management programs have been set up in North America, far less has been done in Europe where populations and harvest are essentially managed at country level with a sole focus on population size. Hence, comparing North American waterfowl populations with European waterfowl populations could be useful in suggesting flyway-scale management options in Europe. In our paper, we analyse historical capture-recapture-recoveries data for the European teal Anas crecca crecca and we compare the computed survival and harvest rates to those obtained from a North American recovery data set for the green-winged teal Anas crecca carolinensis, its sister taxon. During 1960-1976, the annual probability of survival was slightly lower in Europe (average over sexes: 0.485 ± 0.101) than in North America (0.545 ± 0.010 for both sexes). Assuming a 30 ring reporting rate, our estimate of the annual harvest rate was about three times higher in Europe (average over sexes: 0.178 ± 0.051) than in North America (average over sexes: 0.071 ± 0.014). Although the European population increased over the study period and continues to do so, such a hunting pressure may potentially reduce our flexibility in managing this population due to uncertainties such as environmental changes, and have deleterious effects in the long term. We use our results to discuss waterfowl research and management in Europe. Initiating studies to estimate ring reporting rate would be an essential first step to properly evaluate the impact of harvest on the dynamics of the teal population in Europe. © 2010 Wildlife Biology.
Lucking R.,The Field Museum |
Tehler A.,Naturhistoriska Riksmuseet |
Bungartz F.,Fundacion Charles Darwin |
Rivas Plata E.,The Field Museum |
And 2 more authors.
American Journal of Botany | Year: 2013
Premise ofthe study: This study elucidates the phylogenetic position of a unique taxon of Graphidaceae occurring on rock in coastal desert areas, assessing its importance for our understanding of the evolution of the largest family of tropical lichenized fungi. Methods: We used maximum likelihood and Bayesian approaches to reconstruct a three-gene phylogeny of Graphidaceae and a Bayesian molecular clock approach to estimate divergence dates for major clades, as well as Bayesian ancestral ecogeography state analysis.Key results: The new genus Redonographa represents a new subfamily, Redonographoideae, sister to subfamily Graphidoideae. Redonographa is exclusively saxicolous and restricted to the American Pacific coast from California to central Chile, including Galapagos. It contains four species: Redonographa chilensis comb. nov., R. saxiseda comb. nov., R. saxorum comb. nov., and R. galapagoensis sp. nov. The genus Gymnographopsis, with a similar ecogeography but differing in excipular carbonization and chemistry, is also included in Redonographoideae, with the species G. chilena from Chile and G. latispora from South Africa. Molecular clock analysis indicates that Redonographoideae diverged from Graphidoideae about 132 million years ago (Ma) in the Early Cretaceous.Conclusions: The divergence date for subfamilies Redonographoideae and Graphidoideae coincides with the early breakup of Gondwana and ancient origin of the Atacama Desert. However, the common ancestor of Redonographoideae plus Graphidoideae was reconstructed to be tropical-epiphytic. Thus, even if Redonographoideae is subtropical-saxicolous, the hypothesis that Graphidoideae evolved from a subtropical-saxicolous ancestor is not supported. © 2013 Botanical Society of America.