共查询到20条相似文献，搜索用时 15 毫秒
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David W. Londe R. Dwayne Elmore Craig A. Davis Samuel D. Fuhlendorf Torre J. Hovick Barney Luttbeg Jimmy Rutledge 《The Journal of wildlife management》2021,85(1):121-134
The influence of weather on wildlife populations has been documented for many species; however, much of the current literature has focused on the effects of weather within a season and consists of short-term studies. The use of long-term datasets that cover a variety of environmental conditions will be essential for assessing possible carry-over effects of weather experienced in one season on behavior and fitness in subsequent seasons. In this study, we evaluated the effects of weather variables measured over multiple temporal scales on the reproductive performance and behavior of greater prairie-chickens (Tympanuchus cupido) in Osage County, Oklahoma, USA, from 2011–2019. Considering weather over a range of temporal extents allowed us to determine the relative importance of short-term weather events, such as daily temperature and precipitation, versus more chronic shifts in weather such as persistent drought on the reproductive performance of greater prairie-chickens. We used an information-theoretic model building approach to develop models describing the effects of daily weather variables and drought conditions on daily nest survival, nest incubation start dates, and clutch size. Daily nest survival was primarily influenced by conditions experienced during incubation with daily nest success declining in years with wetter than average springs and during extreme precipitation events. Daily nest survival also declined under higher maximum daily temperatures, especially in years with below-average rainfall. Greater prairie-chickens began nesting earlier and had smaller clutch sizes for initial nests and renests in years with warmer temperatures prior to the nesting season. Additionally, incubation of nests started later in drought years, indicating carry-over effects in greater prairie-chicken reproductive behaviors. Our work shows that if the weather in the Great Plains becomes more variable, with increasing frequency of drought and extreme precipitation events, wildlife species that inhabit these grassland landscapes will likely experience changes in reproduction, potentially influencing future populations. © 2020 The Wildlife Society. 相似文献
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Kalysta Adkins Charlotte L. Roy David E. Andersen Robert G. Wright 《The Journal of wildlife management》2019,83(6):1415-1426
Both the abundance of greater prairie-chickens (Tympanuchus cupido pinnatus) and the area of grassland enrolled in the Conservation Reserve Program (CRP) in northwestern Minnesota, USA, have recently declined. Although wildlife conservation is a stated objective of the CRP, the impact of the CRP on greater prairie-chicken populations has not been quantified. To address that information need, we evaluated the association between greater-prairie chicken lek density (leks/km2), the number of males at leks (males/lek), and CRP enrollments in the context of landscape structure and composition in northwestern Minnesota. Using data from standardized prairie-chicken surveys and land cover in 17 41-km2 survey blocks during 2004–2016, we used a mixed-effect model and a layered approach in an information-theoretic framework at multiple spatial scales to identify covariates related to prairie-chicken abundance. At the landscape scale, lek density was best explained by the amount of CRP grassland and wetland, grassland and wetland with long-term conservation goals (state, federal, and The Nature Conservancy owned); other wetlands managed with variable or no continuity in conservation goals; the contiguity of grasslands; and the number of patches of grasslands and wetlands in each survey block each year. Increasing the amount of CRP grassland in 41-km2 survey blocks by 1 km2 (2.4%) resulted in a corresponding increase of 6% in lek density. At the lek scale, the number of males per lek was best explained by the amount of CRP grassland and other grassland, CRP wetland and other wetland, forests, developed areas, shrubland, and the contiguity of CRP grassland. Increasing the amount of CRP grassland in the 2-km breeding-cycle habitat radius around a lek by 25% (3 km2) corresponded to a 5% increase in males per lek. Our results suggest that both increasing the quantity of grassland CRP and wetland CRP enrollments and aggregating CRP grassland enrollments may increase greater prairie-chicken abundance. © 2019 The Wildlife Society. 相似文献
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Kalysta Adkins Charlotte L. Roy Robert G. Wright David E. Andersen 《The Journal of wildlife management》2021,85(1):27-40
The Conservation Reserve Program (CRP) has the potential to influence the distribution and abundance of grasslands in many agricultural landscapes, and thereby provide habitat for grassland-dependent wildlife. Greater prairie-chickens (Tympanuchus cupido pinnatus) are a grassland-dependent species with large area requirements and have been used as an indicator of grassland ecosystem function; they are also a species of conservation concern across much of their range. Greater prairie-chicken populations respond to the amount and configuration of grasslands and wetlands in agriculturally dominated landscapes, which in turn can be influenced by the CRP; however, CRP enrollments and enrollment caps have declined from previous highs. Therefore, prioritizing CRP reenrollments and new enrollments to achieve the greatest benefit for grassland-dependent wildlife seems prudent. We used models relating either lek density or the number of males at leks to CRP enrollments and the resulting landscape structure to predict changes in greater prairie-chicken abundance related to changes in CRP enrollments. We simulated 3 land-cover scenarios: expiration of existing CRP enrollments, random, small-parcel (4,040 m2) addition of CRP grasslands, and strategic, large-parcel (80,000 m2) addition of CRP grasslands. Large-parcel additions were the average enrollment size in northwestern Minnesota, USA, within the context of a regional prairie restoration plan. In our simulations of CRP enrollment expirations, the abundance of greater prairie-chickens declined when grassland landscape contiguity declined with loss of CRP enrollments. Simulations of strategic CRP enrollment with large parcels to increase grassland contiguity more often increased greater prairie-chicken abundance than random additions of the same area in small parcels that did not increase grassland contiguity. In some cases, CRP enrollments had no or a negative predicted change in greater prairie-chicken abundance because they provided insufficient grassland contiguity on the landscape, or increased cover-type fragmentation. Predicted greater prairie-chicken abundance increased under large-parcel and small-parcel scenarios of addition of CRP grassland; the greatest increases were associated with large-parcel additions. We suggest that strategic application of the CRP to improve grassland contiguity can benefit greater prairie-chicken populations more than an opportunistic approach lacking consideration of the larger landscape context. Strategic implementation of the CRP can benefit greater prairie-chicken populations in northwestern Minnesota, and likely elsewhere in landscapes where grassland continuity may be a limiting factor. © 2020 The Wildlife Society. 相似文献
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不同类型镉积累水稻细胞镉化学形态及亚细胞和分子分布 总被引：14，自引：0，他引：14
利用水培试验结合亚细胞组分分级分离和凝胶过滤等技术,研究了水稻根和叶中镉的化学结合形态及其亚细胞和分子分布,比较了低镉积累品种“广源占No.3”和高镉积累品种 “珍桂矮”的差异.结果表明：随着营养液中镉浓度的升高,根和叶亚细胞镉含量显著上升,大部分镉积累在细胞壁（FⅠ）和细胞可溶部分（FⅢ）.高镉积累品种“珍桂矮”根和叶中可溶部分镉含量显著高于低镉积累品种“广源占No.3”.根和叶各种形态镉中,以氯化钠提取态占优势,其次是醋酸提取态,盐酸提取态镉含量最低.与“广源占No.3”相比,“珍桂矮”中迁移性较强的去离子水和乙醇提取态镉比例较高.凝胶过滤结果表明,两种类型的水稻可溶部分镉的出峰位置与样品流份中可溶性蛋白的出峰位置大致相同.可溶部分中的镉大多与分子量为3kD的物质结合,属于植物鳌合肽（PCs）或低分子量物质.“广源占No.3” 根系中镉与PCs配合的组分（Cd-PCs）含量远小于“珍桂矮”.“广源占No.3”细胞可溶部分较低的镉含量以及根系中较少的Cd-PCs形成量,降低了镉的移动及其向地上部转运的可能性. 相似文献
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Lance B. McNew Thomas J. Prebyl Brett K. Sandercock 《The Journal of wildlife management》2012,76(1):38-47
We investigated the site occupancy dynamics of greater prairie-chickens at Konza Prairie Biological Station, a protected site in northeastern Kansas that is managed for ecological research. We surveyed the site during mid-Mar to mid-May, 1981–2008, and recorded detections of birds in a grid of 6.3 ha survey plots (n = 187 plots). We used multiseason occupancy models to estimate the probabilities of occupancy (ψ) and detection (p), and tested whether land cover in woody vegetation, and land use with prescribed fire or grazing management influenced the dynamic processes of site colonization and local extinction. Probability of detection per site was consistently <1 and varied among years (p = 0.12–0.82). Site occupancy of prairie-chickens declined 40% over the study period from a high of ψ = 0.19 ± 0.02 SE in 1981 to a low of 0.11 ± 0.03 in 2008, despite protection from disturbance at leks and losses to harvest. We found that different sets of environmental factors impacted the probabilities of colonization and local extinction. Probability of colonization for an unoccupied site was negatively associated with the proportion of site occupied by woodland cover (β = −1.25), and was lower for grazed sites (β = −0.62). In contrast, probability of local extinction was affected by a weak interaction between grazing and average frequency of prescribed fire (β = −1.01), but model-averaged slope coefficients were not statistically different than 0. To conserve prairie-chickens, we recommend prairies be managed with combinations of prescribed fire and grazing that maintain a heterogeneous mosaic of prairie habitats, while preventing woody encroachment. To assess biotic responses to land management practices, field sampling should be based on occupancy models or similar techniques that account for imperfect detection. © 2011 The Wildlife Society. 相似文献
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Jonathan D. Lautenbach David A. Haukos Joseph M. Lautenbach Christian A. Hagen 《The Journal of wildlife management》2021,85(8):1699-1710
Across portions of the western Great Plains in North America, natural fire has been removed from grassland ecosystems, decreasing vegetation heterogeneity and allowing woody encroachment. The loss of fire has implications for grassland species requiring diverse vegetation patches and structure or patches that have limited occurrence in the absence of fire. The lesser prairie-chicken (Tympanuchus pallidicinctus) is a declining species of prairie-grouse that requires heterogeneous grasslands throughout its life history and fire has been removed from much of its occupied range. Patch-burn grazing is a management strategy that re-establishes the fire-grazing interaction to a grassland system, increasing heterogeneity in vegetation structure and composition. We evaluated the effects of patch-burn grazing on lesser prairie-chicken space use, habitat features, and vegetation selection during a 4-year field study from 2014–2017. Female lesser prairie-chickens selected 1- and 2-year post-fire patches during the lekking season, ≥4-year post-fire patches during the nesting season, and year-of-fire and 1-year post-fire patches during post-nesting and nonbreeding seasons. Vegetation selection during the lekking season was not similar to available vegetation in selected patches, suggesting that lesser prairie-chickens cue in on other factors during the lekking season. During the nesting season, females selected nest sites with greater visual obstruction, which was available in ≥4-year post-fire patches; during the post-nesting season, females selected sites with 15–25% bare ground, which was available in the year-of-fire, 1-year post-fire, and 2-year post-fire patches; and during the nonbreeding season they selected sites with lower visual obstruction, available in the year-of-fire and 1-year post-fire patches. Because lesser prairie-chickens selected all available time-since-fire patches during their life history, patch-burn grazing may be a viable management tool to restore and maintain lesser prairie-chicken habitat on the landscape. © 2021 The Wildlife Society. 相似文献
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基于Landsat TM土地覆盖分类数据和MODIS地表温度数据,探讨京津唐城市群不同土地覆盖的地表温度(7日),并采用常用的普通线性回归(OLS)和地理加权回归(GWR)方法分别拟合土地覆盖比例与地表温度的关系.结果表明: 研究区不同土地覆盖类型的地表温度差异明显,人工表面(40.92±3.49 ℃)和耕地(39.74±3.74 ℃)的平均温度较高,林地(34.43±4.16 ℃)和湿地(35.42±4.33 ℃)的平均温度较低;土地覆盖比例与地表温度显著相关,且两者之间的定量关系存在空间非稳定性,地理位置以及周围环境影响的差异是空间非稳定性产生的主要原因;GWR模型的拟合结果优于OLS模型(RGWR2>ROLS2),并且GWR模型可以量化土地覆盖比例与地表温度两者关系的空间非稳定性特征. 相似文献
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采用双向指示种分析法(TWINSPAN)和去趋势典范对应分析法(DCCA),以三峡库区典型次级河流澎溪河上游东河为研究对象,从植物种、植物群落与环境因子之间的相互关系,研究山地河流河岸植被的空间分布规律。结果表明:河岸植物群落包括4个森林类型、11个灌丛和灌草丛类型。海拔和人为干扰对河岸带植物群落空间分布具有主导作用。河岸植物群落具有明显的沿海拔梯度变化的垂直梯度格局;沿河流纵向和侧向梯度变化,河岸植物群落具有典型的\"斑块状、片段化\"分布格局;从流域整体看,河岸植物群落具有典型的次生性特征。 相似文献
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2011年和2012年的6-8月,考察了分布于巴音布鲁克自然保护区的大天鹅(Cygnus cygnus)种群,分析了大天鹅巢址选择特征和育雏期生境选择特征。在野外共记录到了26个大天鹅巢址。与对照样方比较发现,植被高度、水深、所在水域面积、距干扰源距离和安全等级存在显著差异。进一步逻辑斯蒂回归分析表明,植被高度、水深和安全等级是影响大天鹅巢址选择的最主要的3种生境因子。采用样线法对育雏期大天鹅的生境选择进行了调查,发现大天鹅对沼泽湿地表现出正选择性,对草地表现出负选择性。样方法调查中,利用样方与对照样方比较发现,9种生境因子均存在显著差异,逻辑斯蒂回归分析表明,距干扰源距离和安全等级是影响大天鹅育雏期生境选择的最重要的两种因子。这样的选择机制有利于大天鹅更好的躲避敌害,顺利完成孵化和育雏工作。 相似文献
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Patrick E. Osborne Giles M. Foody Susana Suárez-Seoane 《Diversity & distributions》2007,13(3):313-323
Despite a growing interest in species distribution modelling, relatively little attention has been paid to spatial autocorrelation and non-stationarity. Both spatial autocorrelation (the tendency for adjacent locations to be more similar than distant ones) and non-stationarity (the variation in modelled relationships over space) are likely to be common properties of ecological systems. This paper focuses on non-stationarity and uses two local techniques, geographically weighted regression (GWR) and varying coefficient modelling (VCM), to assess its impact on model predictions. We extend two published studies, one on the presence–absence of calandra larks in Spain and the other on bird species richness in Britain, to compare GWR and VCM with the more usual global generalized linear modelling (GLM) and generalized additive modelling (GAM). For the calandra lark data, GWR and VCM produced better-fitting models than GLM or GAM. VCM in particular gave significantly reduced spatial autocorrelation in the model residuals. GWR showed that individual predictors became stationary at different spatial scales, indicating that distributions are influenced by ecological processes operating over multiple scales. VCM was able to predict occurrence accurately on independent data from the same geographical area as the training data but not beyond, whereas the GAM produced good results on all areas. Individual predictions from the local methods often differed substantially from the global models. For the species richness data, VCM and GWR produced far better predictions than ordinary regression. Our analyses suggest that modellers interpolating data to produce maps for practical actions (e.g. conservation) should consider local methods, whereas they should not be used for extrapolation to new areas. We argue that local methods are complementary to global methods, revealing details of habitat associations and data properties which global methods average out and miss. 相似文献
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Philip D. McLoughlin Douglas W. Morris Daniel Fortin Eric Vander Wal Adrienne L. Contasti 《The Journal of animal ecology》2010,79(1):4-12
1. Describing distribution and abundance is requisite to exploring interactions between organisms and their environment. Recently, the resource selection function (RSF) has emerged to replace many of the statistical procedures used to quantify resource selection by animals.
2. A RSF is defined by characteristics measured on resource units such that its value for a unit is proportional to the probability of that unit being used by an organism. It is solved using a variety of techniques, particularly the binomial generalized linear model.
3. Observing dynamics in a RSF – obtaining substantially different functions at different times or places for the same species – alerts us to the varying ecological processes that underlie resource selection.
4. We believe that there is a need for us to reacquaint ourselves with ecological theory when interpreting RSF models. We outline a suite of factors likely to govern ecologically based variation in a RSF. In particular, we draw attention to competition and density-dependent habitat selection, the role of predation, longitudinal changes in resource availability and functional responses in resource use.
5. How best to incorporate governing factors in a RSF is currently in a state of development; however, we see promise in the inclusion of random as well as fixed effects in resource selection models, and matched case–control logistic regression.
6. Investigating the basis of ecological dynamics in a RSF will allow us to develop more robust models when applied to forecasting the spatial distribution of animals. It may also further our understanding of the relative importance of ecological interactions on the distribution and abundance of species. 相似文献
2. A RSF is defined by characteristics measured on resource units such that its value for a unit is proportional to the probability of that unit being used by an organism. It is solved using a variety of techniques, particularly the binomial generalized linear model.
3. Observing dynamics in a RSF – obtaining substantially different functions at different times or places for the same species – alerts us to the varying ecological processes that underlie resource selection.
4. We believe that there is a need for us to reacquaint ourselves with ecological theory when interpreting RSF models. We outline a suite of factors likely to govern ecologically based variation in a RSF. In particular, we draw attention to competition and density-dependent habitat selection, the role of predation, longitudinal changes in resource availability and functional responses in resource use.
5. How best to incorporate governing factors in a RSF is currently in a state of development; however, we see promise in the inclusion of random as well as fixed effects in resource selection models, and matched case–control logistic regression.
6. Investigating the basis of ecological dynamics in a RSF will allow us to develop more robust models when applied to forecasting the spatial distribution of animals. It may also further our understanding of the relative importance of ecological interactions on the distribution and abundance of species. 相似文献
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John D. Kraft David A. Haukos Matthew R. Bain Mindy B. Rice Samantha Robinson Dan S. Sullins Christian A. Hagen James Pitman Joseph Lautenbach Reid Plumb Jonathan Lautenbach 《The Journal of wildlife management》2021,85(2):354-368
Grazing management recommendations often sacrifice the intrinsic heterogeneity of grasslands by prescribing uniform grazing distributions through smaller pastures, increased stocking densities, and reduced grazing periods. The lack of patch-burn grazing in semi-arid landscapes of the western Great Plains in North America requires alternative grazing management strategies to create and maintain heterogeneity of habitat structure (e.g., animal unit distribution, pasture configuration), but knowledge of their effects on grassland fauna is limited. The lesser prairie-chicken (Tympanuchus pallidicinctus), an imperiled, grassland-obligate, native to the southern Great Plains, is an excellent candidate for investigating effects of heterogeneity-based grazing management strategies because it requires diverse microhabitats among life-history stages in a semi-arid landscape. We evaluated influences of heterogeneity-based grazing management strategies on vegetation structure, habitat selection, and nest and adult survival of lesser prairie-chickens in western Kansas, USA. We captured and monitored 116 female lesser prairie-chickens marked with very high frequency (VHF) or global positioning system (GPS) transmitters and collected landscape-scale vegetation and grazing data during 2013–2015. Vegetation structure heterogeneity increased at stocking densities ≤0.26 animal units/ha, where use by nonbreeding female lesser prairie-chickens also increased. Probability of use for nonbreeding lesser prairie-chickens peaked at values of cattle forage use values near 37% and steadily decreased with use ≥40%. Probability of use was positively affected by increasing pasture area. A quadratic relationship existed between growing season deferment and probability of use. We found that 70% of nests were located in grazing units in which grazing pressure was <0.8 animal unit months/ha. Daily nest survival was negatively correlated with grazing pressure. We found no relationship between adult survival and grazing management strategies. Conservation in grasslands expressing flora community composition appropriate for lesser prairie-chickens can maintain appropriate habitat structure heterogeneity through the use of low to moderate stocking densities (<0.26 animal units/ha), greater pasture areas, and site-appropriate deferment periods. Alternative grazing management strategies (e.g., rest-rotation, season-long rest) may be appropriate in grasslands requiring greater heterogeneity or during intensive drought. Grazing management favoring habitat heterogeneity instead of uniform grazing distributions will likely be more conducive for preserving lesser prairie-chicken populations and grassland biodiversity. © 2021 The Wildlife Society. 相似文献
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Ethan S. Lula Blake Lowrey Kelly M. Proffitt Andrea R. Litt Julie A. Cunningham Carson J. Butler Robert A. Garrott 《The Journal of wildlife management》2020,84(3):588-600
Rocky Mountain bighorn sheep (Ovis canadensis) restoration continues to be a challenge throughout western North America despite nearly a century of efforts dedicated to the species' recovery. Though bighorn sheep restoration may be constrained by several environmental factors and behavioral tendencies, areas with unrealized restoration potential may exist if novel restoration strategies are considered. We used global positioning system (GPS) location data from 27 female bighorn sheep within the southern portion of the Madison Range in southwest Montana, USA, 2015–2017, to develop and validate winter and summer habitat models, which we extrapolated throughout the entire Madison Range to identify potential seasonal habitat. We estimated potential bighorn sheep minimum population estimates within the extrapolation area by linking our top-ranked winter habitat model to population count data. During summer, female bighorn sheep selected areas characterized by rugged and steep terrain, reduced canopy cover, southwestern aspects, and ridgelines. During winter, female bighorn sheep selected areas characterized by low elevations, southwestern aspects, steep slopes, reduced canopy cover, ridgelines, high normalized difference vegetation index amplitude, and areas close to steep terrain. Predicted summer habitat was concentrated along the high-elevation ridgelines associated with steep slopes and reduced canopy cover. Predicted winter habitat occurred in a non-contiguous distribution primarily along the low-elevation, southwest-facing aspects along the western slopes of the Madison Range. Our results suggest that the Madison Range may be capable of supporting 780–1,730 animals, which is 2–4 times the number of bighorn sheep currently observed within the range. Further, our findings provide managers with a quantification of female bighorn sheep habitat and suggests that a strategy focused on establishing a metapopulation through a series of within-range translocations may enhance bighorn sheep restoration. We suggest that similar restoration opportunities may be common in other unoccupied areas of bighorn sheep historical range. © 2020 The Wildlife Society. 相似文献
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为研究渤海鱼类资源早期补充过程,本文将地理加权回归法(GWR)引入栖息地指数(HSI)模型,选取海表温度、海表盐度、水深和叶绿素a浓度4个环境因子建立基于GWR的渤海沙氏下鱵鱼仔稚鱼的HSIGWR模型.模拟发现:在2015年8月渤海的HSIGWR模型中,海表温度和叶绿素a浓度为全局变量,两者的回归系数分别为-0.027和0.006,对HSI影响较小.海表盐度和水深为局地变量,两者回归系数绝对值的平均值分别为0.075和0.129,对HSI的影响较大.其中,海表盐度在渤海中部与HSI呈负相关,负相关系数最大,为-0.3,在三湾呈微弱正相关,相关系数最大值为0.1;水深在整个渤海均与HSI呈负相关,且在三湾的负相关程度明显大于渤海中部,三湾的负相关系数最大,为-0.16.该HSIGWR模型的泊松相关系数为0.705,拟合效果较好,可为今后的鱼类栖息地环境研究提供一种新的方法. 相似文献