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81.
Juan C. Alonso Carlos Palacín Javier A. Alonso Carlos A. Martín 《Behavioral ecology and sociobiology》2009,63(12):1705-1715
Radio tracking of 142 males captured at 44 leks in Spain showed that partial migration of great bustard males in summer is
a widespread behaviour in many Iberian populations, in contrast to their previously assumed sedentariness. A variable number
of males migrated immediately after mating to summering areas with lower temperatures and human population densities and more
trees and rainfall levels than the breeding sites. Birds selected there fields with trees and sunflower crops which provided
shade during the hottest midday hours and protective cover against predators. Males breeding in areas with higher July temperatures
had a higher tendency to migrate, and males from hotter, southern regions migrated longer distances than those from milder,
northern regions and showed a preferred northward direction. These results confirmed various predictions from the weather
sensitivity hypothesis, suggesting that summer migration of great bustard males represents primarily an adaptation to escape
the summer heat of most breeding areas in central and southern Iberia. The hypothesis that males migrated to benefit from
higher food availability at the summering areas could not be rejected by our results. Finally, migrating males also gained
more tranquillity during the post-breeding moult due to the lower human population density at the summering areas. Summer
migration of Iberian great bustard males may thus be interpreted as a form of behavioural thermoregulation which has not been
described for other Palaearctic populations of this species or for other bird species breeding in temperate latitudes. 相似文献
82.
83.
Guiomar Rotllant Francisco Javier Moyano Mireia Andrés Alicia Estévez Manuel Díaz Enric Gisbert 《Marine Biology》2010,157(10):2215-2227
The effect of food deprivation on larval performance of the spider crab Maja brachydactyla was studied in terms of survival, moulting capacity, size, weight and enzymatic activities. Five feeding treatments that
differed in the initial age of first feeding larvae (fed from hatching, 2, 4 and 6 days post-hatching and unfed) were tested
for 20 days. Newly hatched larvae kept without food supply lasted for 10 days and did not moult; with 50% survival observed
at 6 days post-hatching. Larvae (zoea I stage) were only able to tolerate 2 days of food deprivation after the onset of exogenous
feeding without their performance being compromised. Multivariate analyses suggest that digestive enzyme activities may be
good indicators of the nutritional condition of larvae. 相似文献
84.
85.
Petra Quillfeldt Javier Martínez Janos Hennicke Katrin Ludynia Anja Gladbach Juan F. Masello Samuel Riou Santiago Merino 《Die Naturwissenschaften》2010,97(9):809-817
Whereas some bird species are heavily affected by blood parasites in the wild, others reportedly are not. Seabirds, in particular,
are often free from blood parasites, even in the presence of potential vectors. By means of polymerase chain reaction, we
amplified a DNA fragment from the cytochrome b gene to detect parasites of the genera Plasmodium, Leucocytozoon, and Haemoproteus in 14 seabird species, ranging from Antarctica to the tropical Indian Ocean. We did not detect parasites in 11 of these species,
including one Antarctic, four subantarctic, two temperate, and four tropical species. On the other hand, two subantarctic
species, thin-billed prions Pachyptila belcheri and dolphin gulls Larus scoresbii, were found infected. One of 28 thin-billed prions had a Plasmodium infection whose DNA sequence was identical to lineage P22 of Plasmodium relictum, and one of 20 dolphin gulls was infected with a Haemoproteus lineage which appears phylogenetically clustered with parasites species isolated from passeriform birds such as Haemoproteus lanii, Haemoproteus magnus, Haemoproteus fringillae, Haemoproteus sylvae, Haemoproteus payevskyi, and Haemoproteus belopolskyi. In addition, we found a high parasite prevalence in a single tropical species, the Christmas Island frigatebird Fregata andrewsi, where 56% of sampled adults were infected with Haemoproteus. The latter formed a monophyletic group that includes a Haemoproteus line from Eastern Asian black-tailed gulls Larus crassirostris. Our results are in agreement with those showing that (a) seabirds are poor in hemosporidians and (b) latitude could be a
determining factor to predict the presence of hemosporidians in birds. However, further studies should explore the relative
importance of extrinsic and intrinsic factors on parasite prevalence, in particular using phylogenetically controlled comparative
analyses, systematic sampling and screening of vectors, and within-species comparisons. 相似文献
86.
Ignacio González-Fernández Victoria Bermejo Susana Elvira Javier Sanz Benjamín S. Gimeno Rocío Alonso 《Atmospheric environment (Oxford, England : 1994)》2010,44(21-22):2507-2517
Modelling ozone (O3) deposition for impact risk assessment is still poorly developed for herbaceous vegetation, particularly for Mediterranean annual pastures. High inter-annual climatic variability in the Mediterranean area makes it difficult to develop models characterizing gas exchange behaviour and air pollutant absorption suitable for risk assessment. This paper presents a new model to estimate stomatal conductance (gs) of Trifolium subterraneum, a characteristic species of dehesa pastures. The MEDPAS (MEDiterranean PAStures) model couples 3 modules estimating soil water content (SWC), vegetation growth and gs. The gs module is a reparameterized version of the stomatal component of the EMEP DO3SE O3 deposition model. The MEDPAS model was applied to two contrasting years representing typical dry and humid springs respectively and with different O3 exposures. The MEDPAS model reproduced realistically the gs seasonal and inter-annual variations observed in the field. SWC was identified as the major driver of differences across years. Despite the higher O3 exposure in the dry year, meteorological conditions favoured 2.1 times higher gs and 56 day longer growing season in the humid year compared to the dry year. This resulted in higher ozone fluxes absorbed by T. subterraneum in the humid year. High inter-family variability was found in gas exchange rates, therefore limiting the relevance of single species O3 deposition flux modelling for dehesa pastures. Stomatal conductance dynamics at the canopy level need to be considered for more accurate O3 flux modelling for present and future climate scenarios in the Mediterranean area. 相似文献
87.
ERIK GÓMEZ‐BAGGETHUN SARA MINGORRÍA VICTORIA REYES‐GARCÍA LAURA CALVET CARLOS MONTES 《Conservation biology》2010,24(3):721-729
Abstract: Researchers and conservation managers largely agree on the relevance of traditional ecological knowledge for natural resource management in indigenous communities, but its prevalence and role as societies modernize are contested. We analyzed the transmission of traditional knowledge among rural local people in communities linked to protected areas in Doñana, southwestern Spain. We studied changes in knowledge related to local practices in agriculture and livestock farming among 198 informants from three generations that cover the period in which the area transited from an economy strongly dependent on local ecosystem services to a market economy with intensified production systems. Our results suggest an abrupt loss of traditional agricultural knowledge related to rapid transformations and intensification of agricultural systems, but maintenance of knowledge of traditional livestock farming, an activity allowed in the protected areas that maintains strong links with local cultural identity. Our results demonstrate the potential of protected areas in protecting remaining bodies of traditional ecological knowledge in developed country settings. Nevertheless, we note that strict protection in cultural‐landscape‐dominated areas can disrupt transmission of traditional knowledge if local resource users and related practices are excluded from ecosystem management. 相似文献
88.
Spatio-temporal modeling of benthic biological species 总被引:1,自引:0,他引:1
The spatial and temporal distribution of the number of benthic species located in an important area under ecological stress (Puerto CALICA, Quintana Roo, Mexico) is analyzed by means of Gaussian Spatial Linear Mixed Models. Following a model-based approach we derive spatial predictions taking into account temporal variations between May 1996 and June 1999. The proposed models were evaluated in terms of their ability to detect the underlying spatial structure for further interpolation. Uncertainty in the prediction could be evaluated by using the Bayesian paradigm. The results can be used as a guide for further environmental management policies in the region. 相似文献
89.
The clearing of forests to obtain land for pasture and agriculture and the replacement of autochthonous species by other faster-growing varieties of trees for timber have both led to the loss of vast areas of forest worldwide. At present, many developed countries are attempting to reverse these effects, establishing policies for the restoration of older woodland systems. Reforestation is a complex matter, planned and carried out by experts who need objective information regarding the type of forest that can be sustained in each area. This information is obtained by drawing up feasibility models constructed using statistical methods that make use of the information provided by morphological and environmental variables (height, gradient, rainfall, etc.) that partially condition the presence or absence of a specific kind of forestation in an area. The aim of this work is to construct a set of feasibility models for woodland located in the basin of the River Liébana (NW Spain), to serve as a support tool for the experts entrusted with carrying out the reforestation project. The techniques used are multilayer perceptron neural networks and support vector machines. Their results will be compared to the results obtained by traditional techniques (such as discriminant analysis and logistic regression) by measuring the degree of fit between each model and the existing distribution of woodlands. The interpretation and problems of the feasibility models are commented on in the Discussion section. 相似文献
90.
Rodríguez-Aguilar Maribel Díaz de León-Martínez Lorena García-Luna Sofía Gómez-Gómez Alejandro González-Palomo Ana Karen Pérez-Vázquez Francisco Javier Díaz-Barriga Fernando Trujillo Joyce Flores-Ramírez Rogelio 《Environmental science and pollution research international》2019,26(25):25825-25833
Environmental Science and Pollution Research - Indoor air pollution is an important risk factor for the generation of lung diseases in developing countries. The indigenous population is... 相似文献