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Pablo M. Vergara Luis O. Meneses Audrey A. Grez Madelaine S. Quiroz Gerardo E. Soto Christian G. Pérez-Hernández Paola A. Diaz Ingo J. Hahn Andrés Fierro 《Landscape Ecology》2017,32(2):279-293
Context
Interactions between landscape-scale processes and fine-grained habitat heterogeneity are usually invoked to explain species occupancy in fragmented landscapes. In variegated landscapes, however, organisms face continuous variation in micro-habitat features, which makes necessary to consider ecologically meaningful estimates of habitat quality at different spatial scales.Objectives
We evaluated the spatial scales at which forest cover and tree quality make the greatest contribution to the occupancy of the long-horned beetle Microplophorus magellanicus (Coleoptera: Cerambycidae) in a variegated forest landscape.Methods
We used averaged data of tree quality (as derived from remote sensing estimates of the decay stage of single trees) and spatially independent pheromone-baited traps to model the occurrence probability as a function of multiple cross-scale combinations between forest cover and tree quality (with scales ranging between 50 and 400 m).Results
Model support and performance increased monotonically with the increasing scale at which tree quality was measured. Forest cover was not significant, and did not exhibit scale-specific effects on the occurrence probability of M. magellanicus. The interactive effect between tree quality and forest cover was stronger than the independent (additive) effects of tree quality and particularly forest cover. Significant interactions included tree quality measured at spatial scales ≥200 m, but cross-scale interactions occurred only in four of the seven best-supported models.Conclusions
M. magellanicus respond to the high-quality trees available in the landscape rather than to the amount of forest per se. Conservation of viable metapopulations of M. magellanicus should consider the quality of trees at spatial scales >200 m.13.
即使是最有进取心的养猪生产者也会忽视水质对猪生产性能的影响。尽管水质检验表明猪场水质仍在可接受的范围内,但水管内积聚起的水藻、细 相似文献
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Eight Toggenburg wether goats were fed either Coastal bermudagrass (Cynodon dactylon) or orchardgrass (Dactylis glomerata)-alfalfa (Medicago sativa) hay (57:43%) in a reversal design. Four markers were used to study the movement of different digesta fractions: erbium for large particles greater than 1,700 microns; ytterbium for medium particles less than 1,700 microns and greater than 500 microns; chromium for small particles less than 500 microns and greater than 32 microns; and cobalt to follow liquid passage. Fecal samples were collected every 4 h for 6 d. The excretion curves obtained for every marker in each animal were used for model selection. One-compartment gamma age-dependent models (gamma 2, 3 and 4 age-dependent), two-compartment (gamma 2 and gamma 3 age-dependent, age-independent) models and a biexponential model were fitted to the data. Residual sums of squares and the Davidson and MacKinnon test were used to select the most appropriate models. These procedures indicated that the models best describing the movement of different digesta fractions through the gastrointestinal tract of goats, in this experiment, were the biexponential model for liquids, gamma 2 two-compartment model for small and medium particles and gamma 3 two-compartment model for large particles. To accurately describe the behavior of different components of digesta in the digestive tract, different mathematical models are required. In general, models that describe the movement of large particles have higher orders of age-dependency than models that describe the passage of liquids or small particles. 相似文献
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J. Quiroz A.M. Martinez L. Zaragoza R. Perezgrovas J.L. Vega-Pla J.V. Delgado 《Livestock Science》2008,116(1-3):156-161
The Tzotziles, a Mayan native group located in Chiapas, Southern Mexico, have sheep breeding as one of their principal means of subsistence. Sheep were introduced in the Americas by the Spaniards in the first half of the XVI Century. Three populations of sheep from Chiapas—Café, Chamula and Chiapas—were typed with 27 microsatellites. Genetic distances were calculated for three Iberian breeds, Spanish Merino, Churra, two Canary Islands breeds, Canaria and Palmera, and the French Mutton Merino (Precoce). In the case of Chiapas sheep most of the markers showed Hardy–Weinberg equilibrium and the fixation index of Fst (0.095) showed a moderate level of genetic differentiation. The three distinct sheep subpopulations (Café, Chamula and Chiapas) are genetically differentiated inside the Chiapas sheep population. These breeds could be historically related to Spanish sheep populations, but have diverged significantly as a result of genetic drift and selection. 相似文献
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Pettersson Jan Quiroz Andres Fahad Ahmed Elham 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(2):135-140
Abstract Experimental results indicate the existence of an inducible system that can temporarily help cereal plants to defend themselves against cereal aphids. The induction is released by volatiles emitted when aphids attack a neighbour plant individual. Similar effects are obtained with mildew attacked plants. The system shows moderate specificity and affects the allocation of biomass in the plant. 相似文献
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在农业动物产品的生产中,由于政府条例的限制和消费者的选择,选用抗生素作为促生长剂日益受到限制.用抗生素作为促生长剂越来越少.为了出口欧盟国家和其它一些海外市场,许多国家的生产商不得不放弃使用抗生素.…… 相似文献
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The effect of Fasciola hepatica parasite burden on the detection of excretory/secretory (E/S) antigens in sera and feces of experimentally infected sheep was evaluated using a double antibody-based capture enzyme-linked immunosorbent assay (ELISA). Four groups of five sheep each were used. The first three groups were infected with 50, 100 and 200 metacercariae of F. hepatica, and the fourth group remained as non-infected control. On the day of infection and weekly thereafter, serum and fecal samples were taken. ELISA detected F. hepatica E/S antigen levels in serum from the first week post-infection (wpi) and in fecal supernatant from the fourth wpi, which were significantly (p<0.05) higher than controls. F. hepatica eggs were not detected until after the eighth wpi. The correlation between absorbance of E/S antigens in serum with the fluke burden was 0.77 (p<0.0001) and in feces 0.76 (p<0.0001) at 12th wpi. The sensitivity of the assay to detect E/S antigens in serum was 86.6% and in feces 93.3%. It is concluded that the ELISA technique used in this study offers a diagnostic alternative for detecting early infections of F. hepatica in sheep. 相似文献
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Estelle Lerceteau Sophie Flipo James Quiroz Jorge Soria Vincent Pétiard Dominique Crouzilat 《Euphytica》1997,95(1):77-87
The quality of Ecuadorian cacao is presently threatened by the introduction of hybrid material. An estimation of genetic diversity
in Ecuador is required in order to avoid the loss of fine flavored cocoa. Genetic variability amongst 60 Ecuadorian genotypes
of Theobroma cacao has been evaluated using molecular and phenotypic markers. The two distance matrices derived from the molecular
and phenotypic data were found to be correlated (R2 = 0.5). Dynamic clustering analyses classified the genotypes in two or three groups depending on the markers used. The genotypes
coming from Sebasti{àn Arteaga (SA) and Balao Chico (BCH) plantations appeared related to each other suggesting a common genetic
origin. They also may be considered as a distinct group with high RFLP homozygosity. The EETP (Estací}on Experimental Tropical
Pichilingue of Ecuador) collection was comprised of more variable genotypes possessing variable heterozygosity levels. The
low heterozygous genotypes may be genetically related to SA and BCH trees, whereas the higher heterozygous genotypes may have
resulted from hybridizations between original Nacional material of Ecuador and genotypes imported from Trinidad at the beginning
of the century. Thus genetic introgression may have occurred giving rise to a range of variation between Nacional and hybrid
forms.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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M. C. Diez A. Quiroz S. Ureta-Zañartu G. Vidal M. L. Mora F. Gallardo R. Navia 《Water, air, and soil pollution》2005,163(1-4):325-339
Allophanic soil, natural and activated by acidification or calcination was used to adsorb organic recalcitrant compounds (lignin and chlorophenols) from biologically pre-treated kraft mill effluent. A synthetic non crystalline aluminosilicate like allophane coated with iron oxide (Al-Si-Fe) was used as control for comparison purposes. It was observed that the adsorption capacity of the allophanic soil increased at higher solid/solution ratio, and at lower pH values. The highest total phenolic compounds removal was obtained between pH 4.0 and 4.5 for natural and activated soil using a solid/solution ratio of 1:5, and for synthetic aluminosilicate using 300 mg in 30 mL of effluent solution. Soil activated by calcination procedure presented the highest total phenolic compounds adsorption capacity (71–85%) for untreated and aerobic or anaerobic pre-treated effluent. The specific chlorophenols analysis indicated that pentachlorophenol (PCP) was almost completely adsorbed onto the allophanic soil (> 99%), and that over 79% of the 2,3,4,6-tetrachlorophenol (TeCP) was adsorbed, independent of the biological pre-treatment type and the soil activation procedure. On the other hand, 2,4-dichlorophenol (DCP) coming from both aerobic and anaerobic treated effluent was poorly removed (24–30%) when natural soil was used for adsorption; whereas in calcinated and acidified soil DCP removal was more than 71%. 相似文献