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ABSTRACT We recorded telemetry locations from 1,129 radiotagged turkeys (Meleagris gallopavo intermedia) on 4 study areas in the Texas Panhandle and southwestern Kansas, USA, from 2000 to 2004. Analyses of telemetry locations indicated both sexes selected riparian vegetative zones. Females did not select grazed or nongrazed pastures for daily movements. However, females did select nongrazed pastures for nest sites on 2 study areas and males selected for grazed pastures at one study area during the breeding season. We compared nest sites (n = 351) to random sites using logistic regression, which indicated height of visual obstruction, percent canopy cover, and percent bare ground provided the highest predictive power (P ≤ 0.003) for characteristics describing nest-site selection. Nest-site vegetative characteristics between vegetative zones differed primarily in composition: upland zone nest sites had more (P ≤ 0.001) shrubs and riparian zone nest sites had more (P ≤ 0.001) grass. There were no differences in measured nest site vegetative characteristics between pasture types, but there were differences between available nesting cover in grazed and nongrazed pastures. Random plots in grazed pastures had less grass cover (P ≤ 0.001) and more bare ground (P = 0.002). Because of cattle impacts on average grass height and availability, grazing would likely have the highest impact on nesting in riparian zones due to turkey use of grass as nesting cover. An appropriate grazing plan to promote Rio Grande turkey nesting habitat would include grazing upland zones in the spring, when it likely has little impact on nesting-site selection, and grazing riparian zones following breeding season completion. Grazing at light to moderate intensities with periods of rest did not affect male turkey pasture use and may have continued to maintain open areas used by male turkeys for displaying purposes.  相似文献   
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The amino acid sequence in a hypertensin   总被引:5,自引:0,他引:5       下载免费PDF全文
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The distributions of a wide range of taxonomic groups are expanding polewards   总被引:11,自引:1,他引:10  
Evidence is accumulating of shifts in species' distributions during recent climate warming. However, most of this information comes predominantly from studies of a relatively small selection of taxa (i.e., plants, birds and butterflies), which may not be representative of biodiversity as a whole. Using data from less well‐studied groups, we show that a wide variety of vertebrate and invertebrate species have moved northwards and uphill in Britain over approximately 25 years, mirroring, and in some cases exceeding, the responses of better‐known groups.  相似文献   
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We isolated 13 polymorphic microsatellite markers from the satin bowerbird, Ptilonorhynchus violaceus from a genomic library enriched in (AAGG)n repetitive elements and characterized them in 20 individuals. The number of alleles ranged from two to 18 per locus with the observed heterozygosity ranging from 0.15 to 1.00. These markers will be useful for analysing questions concerning parentage, population genetic structure and models of speciation.  相似文献   
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We isolated 10 polymorphic microsatellite markers for the silky short‐tailed bat, Carollia brevicauda, from genomic libraries enriched for (AAGG)n repetitive elements. The number of alleles ranged from six to 25 per locus with the observed heterozygosity ranging from 0.29 to 0.95. These markers will be useful for analysis of questions concerning population genetic structure and models of speciation. Results of cross‐species amplification in Carollia castanea and Carollia perspicillata are also reported.  相似文献   
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Abstract: The physiological impacts and fitness costs of parasitism by an introduced ectoparasitic fly, Philornis downsi (Muscidae), were studied in nestlings of Darwin's Small Ground Finch, Geospiza fuliginosa (Geospizinae), on the Galápagos Archipelago. Whole blood haemoglobin (Hb) concentration was used to measure host response to ectoparasitism due to its high repeatability and validity, as well as for its key role in aerobic activities that affect fitness, such as flight capacity and nestling begging intensity. Increased numbers of ectoparasitic larvae of P. downsi were strongly correlated with lower Hb levels in nestlings in the absence of blood parasites. Furthermore, immature red blood cell counts were negatively correlated with Hb level and positively correlated with P. downsi intensity. Nestlings with high levels of parasitism suffered higher mortality, which varied with clutch size. Our results provide evidence that endemic Galápagos bird populations are physiologically compromised by P. downsi and experience substantial fitness costs due to ectoparasitism.  相似文献   
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We isolated 10 polymorphic microsatellite markers for the skink Mabuya affinis from genomic libraries enriched for (AAGG)n and (AAAG)n repetitive elements. The number of alleles ranged from eight to 13 per locus with the observed heterozygosity ranging from 0.60 to 0.92. These markers will be useful for analysis of questions concerning population genetic structure and models of speciation.  相似文献   
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