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排序方式: 共有433条查询结果,搜索用时 15 毫秒
271.
In 2001, the New Jersey Department of Environmental Protection (NJDEP) adopted rules specifically protecting vernal pool habitat for the first time. Vernal pools are small isolated temporary bodies of water that provide critical breeding habitat for a number of amphibian species. To implement these rules and ultimately afford vernal pools protection, the NJDEP first needed to assemble a statewide database of vernal pool locations. In response, the Rutgers University Center for Remote Sensing and Spatial Analysis (CRSSA) was funded to develop a cost effective technique to map vernal pool locations statewide. The objective of CRSSA's mapping effort was to develop a complete potential vernal pool database to be able to identify individual isolated vernal pools as well as areas of high local density, or 'hotspots'. CRSSA used visual interpretation of leaf-off color infrared digital orthophotography in a computerized GIS environment to identify and map over 13,000 potential vernal pools. Using the 1m scale imagery, we determined the minimum detectable pool size to be on the order of 0.02 ha in size. Subsequent field checking has revealed a 12% error of commission that was due to our inclination towards erring on the side of inclusion in mapping many water features as potential vernal pools. For a vernal pool to receive regulated protection, it must be 'certified' that it serves as habitat for obligate or facultative vernal pool amphibian species. To aid in these efforts, CRSSA developed an interactive internet mapping site to assist NJDEP and its citizen volunteer corps in locating and navigating to their survey areas and to facilitate the on-line submittal of survey observations. 相似文献
272.
Ecological niche suitability model with an application in Taojiang land use planning 总被引:4,自引:0,他引:4
EcologicalnichesuitabilitymodelwithanapplicationinTaojianglanduseplanningOuyangZhiyun;WeismanJason;WangRusong(ResearchCenterf... 相似文献
273.
Roitberg BD Gillespie DR Quiring DM Alma CR Jenner WH Perry J Peterson JH Salomon M VanLaerhoven S 《Die Naturwissenschaften》2005,92(9):431-434
Evolutionary and ecological transitions from carnivorous to omnivorous feeding may be constrained by the ability of the animal
to cope with disparate types of foods, even if preadaptations for such behaviour exist. The omnivorous true bug, Dicyphus hesperus (Hemiptera: Miridae) requires both animals (small, soft-bodied insects) and plants in its diet and obtains the majority of
its dietary and metabolic water from plant feeding. Serrations on the lateral margins of the mandibular stylets wear with
age, and this wear is exacerbated when the insects feed on plants compared to those provided free water and no plants. D. hesperus that feed on plants attack fewer prey but consumed similar amounts of prey tissue compared to individuals that were provided
free water. Although others have shown mandible wear for plant-chewing animals we show for the first time that plant feeding
can impose similar wear on plant-piercing animals as well. 相似文献
274.
Michel Jan Niklas Cathy Trudinger Jason Lowe Ben Matthews Brd Romstad Christiano Pires de Campos Natalia Andronova 《Environmental Science & Policy》2005,8(6):614
This paper evaluates the influence of different policy-related and scientific choices on the calculated regional contributions to global climate change (the “Brazilian Proposal”). Policy-related choices include the time period of emissions, the mix of greenhouse gases and different indicators of climate change impacts. The scientific choices include historical emissions and model representations of the climate system. We generated and compared results of several simple climate models. We find that the relative contributions of different nations to global climate change—from emissions of greenhouse gases alone—are quite robust, despite the varying model complexity and differences in calculated absolute changes. For the default calculations, the average calculated contributions to the global mean surface temperature increase in 2000 are about 40% from OECD, 14% from Eastern Europe and Former Soviet Union, 24% from Asia and 22% from Africa and Latin America. Policy-related choices, such as time period of emissions, climate change indicator and gas mix generally have larger influence on the results than scientific choices. More specifically, choosing a later attribution start date (1990 instead of 1890) for historical emissions, decreases the contributions of regions that started emitting early, such as the OECD countries by 6 percentage points, whereas it increases the contribution of late emitters such as Asia by 8 percentage points. However, only including the fossil CO2 emissions instead of the emissions of all Kyoto gases (fossil and land use change), increases the OECD contributions by 21 percentage points and decreases the contribution of Asia by 14 percentage points. 相似文献
275.
The impact of interactions between the earthworms Eisenia foetida and Lumbricus terrestris and the plants Cucurbita pepo and Cucurbita maxima on the uptake of weathered p,p'-DDE from soil was determined. Although some combinations of earthworm and plant species caused significant changes in the p,p'-DDE burden in both organisms, the effects were species specific. Contaminant bioconcentration in C. pepo was increased slightly by E. foetida and by 3-fold when the plant was grown with L. terrestris. E. foetida had no effect on the contaminant BCF by C. maxima, but L. terrestris caused a 2-fold reduction in p,p'-DDE uptake by the plant. Contaminant levels in E. foetida and L. terrestris were unaffected by C. pepo. When grown with C. maxima, the concentration of p,p'-DDE decreased by approximately 4-fold and 7-fold in E. foetida and L. terrestris, respectively. The data suggest that the prediction of contaminant bioavailability should consider interactions among species. 相似文献
276.
In the present study, we investigated the contribution of methylsulfonyl metabolite derived from 1,2,4-trichlorobenzene (1,2,4-TCB) on the delta-aminolevulinic acid (ALA) synthetase induction by the parent compound in rats. The time courses of increasing of hepatic microsomal total cytochrome P450 content after a single i.p. administration of 1,2,4-TCB (1.36 mmol/kg), and 2,3,5- and 2,4,5-trichlorophenyl methyl sulfones (2,3,5- and 2,4,5-TCPSO2Mes) (50 micromol/kg each) were in parallel with those of increasing of the total heme content in liver microsomes. 1,2,4-TCB significantly increased the heme oxygenase activity, but 2,3,5- and 2,4,5-TCPSO2Mes did not. On the other hand, 1,2,4-TCB and 2,3,5-TCPSO2Me markedly enhanced the ALA synthetase activity. No change was observed in this enzyme activity after the administration of 2,4,5-TCPSO2Me. After the administration of 1,2,4-TCB to the rats treated with DL-buthionine-(S,R)-sulfoximine (BSO) and to the non-BSO-treated rats, the concentrations of both 2,3,5- and 2,4,5-TCPSO2Mes were significantly lower in liver of the BSO-treated rats than in liver of the non-BSO-treated rats. Additionally, the 1,2,4-TCB did not elevate the ALA synthetase activity in the BSO-treated rats. On the other hand, the administration of 2,3,5-TCPSO2Me to BSO-treated rats resulted in induction of ALA synthetase. The results strongly suggest that the methyl sulfone derived from 1,2,4-TCB, i.e., 2,3,5-TCPSO2Me, contributes highly to the induction of the ALA synthetase activity by the parent compound. 相似文献
277.
In the terrestrial environment, standardized protocols are available for measuring the exposure and effects of contaminants to invertebrates, but none currently exist for vertebrates. In an effort to address this, we proposed that developing lizard embryos may be used as a terrestrial vertebrate model. Lizard eggs may be particularly susceptible to soil contamination and in ovo exposure may affect hatchling size, mortality, as well as thyroid function. Toxicant-induced perturbations of thyroid function resulting from in ovo chemical exposure may result in toxicity during the critical perinatal period in reptiles. Fertilized Eastern fence lizard (Sceloporus undulatus) eggs were placed in cadmium (Cd)-spiked expanded perlite (0, 1.48, 14.8, 148, 1480, 14 800 μg Cd/g, nominal concentrations), artificially incubated at 28 °C, and examined daily for mortality. Whole lizard hatchlings as well as failed hatches were homogenized in ethanol and the homogenate was divided for Cd body residue analysis and thyroid hormone (triiodothyronine (T3) and thyroxine (T4)) analyses. Acute mortality was observed in the two highest doses (1480 and 14 800 μg Cd/g). Cadmium body residues showed a higher internal concentration with increasing exposure concentration indicating uptake of Cd. There was a decrease in T3:T4 ratio at the highest surviving dose (148 μg Cd/g), however, there were no differences observed in hatchling size measured as weight and snout-vent length, or in whole body thyroid hormone levels. In summary, this study has shown Cd amended to a solid phase representing soil (perlite) can traverse the thin, parchment-like shell membrane of the fence lizard egg and bioaccumulate in lizard embryos. We believe this study is a good first step in investigating and evaluating this species for use as a model. 相似文献
278.
Irruptive population dynamics appear to be widespread in large herbivore populations, but there are few empirical examples from long time series with small measurement error and minimal harvests. We analyzed an 89-year time series of counts and known removals for pronghorn (Antilocapra americana) in Yellowstone National Park of the western United States during 1918-2006 using a suite of density-dependent, density-independent, and irruptive models to determine if the population exhibited irruptive dynamics. Information-theoretic model comparison techniques strongly supported irruptive population dynamics (Leopold model) and density dependence during 1918-1946, with the growth rate slowing after counts exceeded 600 animals. Concerns about sagebrush (Artemisia spp.) degradation led to removals of >1100 pronghorn during 1947-1966, and counts decreased from approximately 700 to 150. The best models for this period (Gompertz, Ricker) suggested that culls replaced intrinsic density-dependent mechanisms. Contrary to expectations, the population did not exhibit enhanced demographic vigor soon after the termination of the harvest program, with counts remaining between 100 and 190 animals during 1967 1981. However, the population irrupted (Caughley model with a one-year lag) to a peak abundance of approximately 600 pronghorn during 1982-1991, with a slowing in growth rate as counts exceeded 500. Numbers crashed to 235 pronghorn during 1992-1995, perhaps because important food resources (e.g., sagebrush) on the winter range were severely diminished by high densities of browsing elk, mule deer, and pronghorn. Pronghorn numbers remained relatively constant during 1996-2006, at a level (196-235) lower than peak abundance, but higher than numbers following the release from culling. The dynamics of this population supported the paradigm that irruption is a fundamental pattern of growth in many populations of large herbivores with high fecundity and delayed density-dependent effects on recruitment when forage and weather conditions become favorable after range expansion or release from harvesting. Incorporating known removals into population models that can describe a wide range of dynamics can greatly improve our interpretation of observed dynamics in intensively managed populations. 相似文献
279.
Russell C. Van Horn Jason C. Buchan Jeanne Altmann Susan C. Alberts 《Behavioral ecology and sociobiology》2007,61(12):1823-1837
Group living provides benefits to individuals while imposing costs on them. In species that live in permanent social groups,
group division provides the only opportunity for nondispersing individuals to change their group membership and improve their
benefit to cost ratio. We examined group choice by 81 adult female savannah baboons (Papio cynocephalus) during four fission events. We measured how each female’s group choice was affected by several factors: the presence of
her maternal kin, paternal kin, age peers, and close social partners, her average kinship to groupmates, and her potential
for improved dominance rank. Maternal kin, paternal kin, and close social partners influenced group choice by some females,
but the relative importance of these factors varied across fissions. Age peers other than paternal kin had no effect on group
choice, and average kinship to all groupmates had the same effect on group choice as did maternal kin alone. Most females
were subordinate to fewer females after fissions than before, but status improvement did not drive female group choice; females
often preferred to remain with social superiors who were their close maternal kin, rather than improving their own social
ranks. We suggest that during permanent group fissions, female baboons prefer to remain with close maternal kin if those are
abundant enough to influence their fitness; if they have too few close maternal kin then females prefer to remain with close
paternal kin, and social bonds with nonkin might also become influential.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
280.
Prasad VK Ortiz A Stinner B McCartney D Parker J Hudgins D Hoy C Moore R 《Environmental monitoring and assessment》2005,110(1-3):141-169
Ohio is typical among the Midwestern and Eastern United States with high levels of water pollutants, the main sources being
from agriculture. In this study, we used a digital elevation model in conjunction with hydrological indices to determine the
role of landscape complexity affecting the spatial and temporal variation in pollutant levels, in one of the most impaired
headwater streams in Ohio. More than eighty five percent of the study area is dominated by agriculture. Spatial distribution
of slope (S), altitude and wetness index along with other watershed parameters such as flow direction, flow accumulation,
stream networks, flow stream orders and erosion index were used within a Geographic Information Systems framework to quantify
variation in nitrate and phosphate loads to headwater streams. Stream monitoring data for nutrient loads were used to correlate
the observed spatial and temporal patterns with hydrological parameters using multiple linear regressions. Results from the
wetness index calculated from a digital elevation model suggested a range of 0.10–16.39, with more than 35% having values
less than 4.0. A Revised Universal Soil Loss Equation (RUSLE) predicted soil loss in the range of 0.01–4.0 t/ha/yr. Nitrate
nitrogen levels in the study area paralleled precipitation patterns over time, with higher nitrate levels corresponding to
high precipitation. Atmospheric deposition through precipitation could explain approximately 35% of total nitrate levels observed
in streams. Among the different topographic variables and hydrological indices, results from the step-wise multiple regression
suggested the following best predictors, (1) elevation range and upstream flow length for nitrate, (2) flow direction and
upstream flow length for ammonia-nitrogen and slope, and (3) elevation range for phosphate levels. Differences in the landscape
models observed for nitrate, phosphate and ammonia-nitrogen in the surface waters were attributed partly to differences in
the chemical activity and source strengths of the different forms of these nutrients through agricultural management practices.
The results identify geomorphologic and landscape characteristics that influence pollutant levels in the study area. 相似文献