94 research outputs found
Nematode parasites of the characid freshwater fish Brycon guatemalensis in the Usumacinta River, Chiapas, Mexico
During the study of the helminth parasites of some fishes of the Usumacinta River in the locality Frontera Corozal (Frontera Echeverria), State of Chiapas, Mexico, 2 species of South American nematodes, Neocucullanus neocucullanus Travassos, Artigas et Pereira, 1928 from Brazil and Rhabdochona acuminata (Molin, 1860) from Brazil, Ecuador and Argentina were recovered from the intestine of the characid fish, Brycon guatemalensis.
Findings of these nematode species represent new host and geographical records.Fil: Caspeta Mandujano, J. M.. Universidad Autónoma de Morelos; MéxicoFil: Cabañas Carranza, G.. Universidad Nacional Autónoma de México; MéxicoFil: Maldonado Salgado, G.. Universidad Nacional Autónoma de México; MéxicoFil: Gosztonyi, Atila Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Cremonte, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentin
Benefits of protected areas for nonbreeding waterbirds adjusting their distributions under climate warming
Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993-2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTISD). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTISD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTISD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming
Mapping of mosquito (Culicidae) breeding sites using predictive geographic information methods
Application of remote sensing and other GIS methods in the subject of mapping mosquito breeding sites has not been premised accordingly. Despite the facts that the duration of field surveys would be shortened and the effectiveness of action plans would be higher with the supportance of computer modelling techniques. This work aimed to evaluate the applicability of digital elevation models and aerial photographs in the prediction of mosquito breeding sites. Relief analysis was carried out seeking depressions based on elevation models created with TIN and kriging interpolation methods. Spectral analysis was performed on aerial photographs to identify the patches of higher water content or moisture. The results show that terrain analysis can not give acceptable results due to its resolution and accuracy. Spectral analysis of normal (visible range) photographs can be a useful tool in predicting of breeding sites. On grasslands the verificitaion revealed 91% correct results
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