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1.
Diet of pine martens in a coastal Atlantic oakwood in western Scotland was assessed over a period of two years (1996-8) in the context of strong potential competition from a diverse guild of other predators also largely dependent on preferred small rodent prey. Analysis of prey remains in fresh droppings showed that despite the potential for competition, martens still preyed extensively on small mammals and birds, preying preferentially on voles and particularly Microtus agrestis L. Invertebrates were also important dietary items, with high intake of beetles (and particularly Geotrupes sp.) from March to September. Predation on birds and intake of earthworms were highest over the winter period; fruits (bramble and rowan berries) were also important over the autumn and (ivy berries) late winter. The diet described is similar to that recorded in other studies, with no significant shifts due to potential competition from other predatory birds and mammals on the same species-poor prey base. However, marten activity in the area was subject to sudden seasonal decline in both sign and sightings and it seems possible that the animals may be making gross range shifts in periods of relative scarcity of high quality foods, moving substantial distances to track local availability of preferred prey.  相似文献   

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On 17 Utah juniper ( Juniperus osteosperma [Torrey] L.) sites studied in Utah, Gymnosporangium inconspicuum was the most common rust fungus, followed in frequency and severity by G. nelsoni, G. kernianum, and G. speciosum . The incidence of G. kernianum was correlated with moderate temperatures and greater than average precipitation. True mistletoe, Phoradendron juniperinum Engelm., was present on seven sites. Incidence of foliage diseases of the mold-mildew type was low on sites with low spring and summer temperatures and high on sites with high summer and fall precipitation. Wood rot was common, and incidence seemed to be correlated with low winter temperatures and low soil nitrate but not with annual precipitation. Needle blight, shoot dieback, and needle cast symptoms were common and considered of abiotic origin. Their nonparasitic nature was indicated by lack of association with pathogenic organisms and the positive correlation of their incidence with winter injury and summer drought factors. Needle blight was also positively correlated with high soil salinity but negatively with high soil calcium regardless of salinity. A nonparametric model was developed that accurately predicted the frequency of the mold-mildew type diseases of J. osteosperma based on measured environmental site factors.  相似文献   

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The interaction between Southwestern dwarf mistletoe, Arceuthobium vaginatum subspecies cryptopodum , infestation and defoliation by the pandora moth, Coloradia pandora pandora , on the Kaibab Plateau in Arizona was evaluated. Heavy defoliation of ponderosa pine, Pinus ponderosa , in 1979 and 1981 resulted in mortality of individual trees in areas of heavy dwarf mistletoe infestation. Postmortem evaluation of ponderosa pines indicated that dead trees had a significantly higher dwarf mistletoe rating than did nearby paired live trees. Of 25 tree pairs evaluated, only two live trees had higher dwarf mistletoe ratings than the paired dead tree. Mean dwarf mistletoe ratings were: live trees 2.9, dead trees 4.6 (6 class dwarf mistletoe rating system). Implications for management of the pandora moth are discussed.     相似文献   

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From October 2003 through April 2006, we collected 565 fleas incidental to a distribution survey of mammals in southwestern South Dakota. Sixty-one specimens, representing 18 species of mammals, possessed 20 species of fleas. The geographic distributions of these flea species revealed 8 new records for the Black Hills and its adjacent grasslands. Four species— Megarthroglossus divisus, Stenoponia americana, Odontopsyllus dentatus, and Amaradix euphorbi —constitute new records for South Dakota, thus increasing the state’s known flea fauna to 42 species. Hunters, trappers, and field biologists should be aware that serosurveillance during the 1990s revealed the presence of sylvatic plague and tularemia in the Black Hills area. Desde octubre de 2003 hasta abril de 2006, colectamos 565 pulgas de manera incidental durante un estudio de la distribución de mamíferos en el suroeste del estado de Dakota del Sur. Los 61 especímenes, que representaban 18 especies de mamíferos, albergaban 20 especies de pulgas. Sus distribuciones geográficas revelaron 8 nuevos registros para las Colinas Negras (Black Hills) y las praderas adyacentes. Cuatro de estas especies ( Megarthroglossus divisus, Stenoponia americana, Odontopsyllus dentatus y Amaradix euphorbi ) constituyen nuevos registros para Dakota del Sur. Esto aumenta el número de especies de pulgas conocidas del estado a 42 especies. Los cazadores, tramperos y biólogos de campo deben estar conscientes de que la vigilancia serológica durante la década de los 1990 reveló la presencia de la plaga silvática y la tularemia en el área de las Colinas Negras.  相似文献   

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Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Peromyscus maniculatus and related small rodents have been examined for ectoparasites in the tundra region of the Rocky Mountain National Park 1974–1979. One hundred and ninety-four P. maniculatus were examined from two tundra sites. Flea infestation rates were 1.9 fleas per mouse examined and 4.1 fleas per infested mouse. Species taken in significant numbers were Monopsyllus thambus (51 percent), Peromyscopsylla hesperomys (34 percent), Malaraeus euphorbi (9 percent), and Catallagia calisheri (4 percent). Peromyscus maniculatus host/flea relationships in the tundra are compared with those in other life zones in the park.    相似文献   

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Eighteen pine marten ( Martes americana ) stomachs and 29 intestinal tracts, collected between October 1983 and March 1984 from northern Colorado, were examined for food items. Voles ( Microtus spp.) occurred most frequently, followed by shrews ( Sorex spp.), insects, and vegetative matter.  相似文献   

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《Journal of Natural History》2012,46(3-4):205-222
The study describes habitat use and temporal occurrence of calling males for an austral anuran assemblage in the Neotropics, southern Brazil. Three study sites (S1 – a permanent river and a stream, S2 – a dam and backwater, S3 – two permanent ponds periodically connected) were sampled between August 2005 and July 2006. The site S3 presented the richest and most diverse assemblage and habitat use within studied sites, and was partitioned by species groups. Richness and abundance of calling males for overall assemblage were seasonal, concentrated in spring and summer and correlated with photoperiod. Temperature, rainfall and air humidity were not correlated with the richness and abundance of calling males. Photoperiod also explained the calling seasons when species were analyzed individually. Habitat use and temporal occurrence were complementary in the partitioning of breeding resources, explaining species coexistence.  相似文献   

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Ponderosa pine conelets in 10 stands on the Coconino and Kaibab national forests were observed periodically from July 1982 until they matured in September 1983. Abortion, ponderosa pine cone beetles ( Conophthorus ponderosae Hopkins), and ponderosa pine coneworms ( Dioryctria sp., probably Auranticella [Grote]) were the significant mortality factors. Cattle, tip moths, and squirrels rarely destroyed conelets or cones.  相似文献   

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During 1995-1997 we conducted a white pine blister rust (WPBR) disease survey in white pines of the Intermountain West. Incidence of WPBR in white pines was 59% overall, 73% in the northern Rocky Mountains, 55% in the middle Rocky Mountains, and 67% in the Sierra Nevada sample stands. Intensity within infected stands averaged 35% and ranged from 2% to 100%. Southward spread of the disease along the western slopes of the Rocky Mountains appears to have slowed or stopped, and the disease was found at the northern and western edges of, but not within, the Great Basin region. Smaller-diameter trees infected with WPBR sustained more severe damage than larger-diameter trees. Mortality and top kill caused by WPBR were very low across the entire study area, but incidence and intensity of the disease appear to have increased substantially in the northern and middle Rocky Mountains since the 1960s.  相似文献   

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Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} A review of the ecological distribution and successional roles of lodgepole pine and trembling aspen in the Southern Rocky Mountains suggests that the two species have different strategies for occupying disturbed sites. Lodgepole pine’s easily dispersed seeds and faster growth from seed in unsuppressed conditions allows it to colonize severe burns, even from remote seed sources. Aspen appears to compensate for ineffective development from seed by vegetative reproduction from durable root stocks, which promotes geographic persistence. Such persistence is achieved by the maintenance of a forest structure conducive to light surface fires, which stimulate suckering and retard conifer invasion, and by the accumulation of soil organic matter, which improves site nutrient retention and water availability.    相似文献   

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We surveyed bats using echolocation calls near inactive mines in the western Great Basin from 2003 to 2007. We identified 14 species of bats during our surveys, with Myotis lucifugus and Lasionycteris noctivagans found at 9 sites and Myotis evotis and Tadarida brasiliensis at 7 sites; all other species were found at less than one-half of the sites. Euderma maculatum, a state-protected species in Nevada, was recorded at 2 sites. Our work provides information that will be useful in managing bat habitat, especially with regard to mining activities.  相似文献   

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