Geographical gradients in the population dynamics of North American prairie ducks.
Geographical gradients in the population dynamics of North American prairie ducks.
复制标题
北美草原鸭种群动态的地理梯度。
DOI：
--
复制
发表时间：
2008
影响因子：
4.8
通讯作者：
Kevin M. Podruzny
中科院分区：
文献类型：
--
作者：
B. Saether;Magnar Lillegård;V. Grøtan;M. Drever;S. Engen;T. Nudds;Kevin M. Podruzny
1.种群动态中的地理梯度可能是由于资源的空间变化影响动态的确定性组成部分（即承载能力、小密度下的特定增长率或密度调节的强度）或由于环境随机性效应的空间变化而发生的。为了评估这些，我们使用了一个分层贝叶斯方法来估计参数表征确定性成分和随机影响的8种鸭（绿头鸭，北方针尾鸭，蓝翅鸭，gadwall，北方铲，美国威金，帆布背和红头鸭（Anas platyrhynchos，A. acuta、尖叶拟谷盗A. discors，A. strepera，A. clypeata、盾叶甲A. americana、Aythya valisineria和Ay.美洲，分别）在北美大草原繁殖，然后测试这些参数是否随纬度变化。2.我们还研究了湿地的可用性，春季温度和冬季降水量的时间变化对人口动态的影响，以确定人口动态的地理梯度是否与环境效应的大尺度变化有关。人口的变异性，作为衡量的人口波动的方差的承载能力K，除canvasback的所有物种随纬度下降。人口变异性的这种下降是由密度依赖性，承载能力和过程方差的强度的纬度梯度的组合，其中的细节因物种而异。3.环境协变量对种群动态的影响也随纬度而变化，特别是绿头鸭，北方针尾鸭和北方铲。然而，环境协变量解释的过程方差的比例，与野鸭除外，往往是小的。4.因此，在草原野鸭种群动态的地理梯度导致纬度梯度的确定性和随机成分，并可能受到空间差异的湿地类型和形状，农业实践和扩散过程的分布。5.这些结果表明，未来的管理，这些物种可以通过实施收获模式，明确占人口丰度的密度效应和环境随机性的空间变化得到改善。
1. Geographic gradients in population dynamics may occur because of spatial variation in resources that affect the deterministic components of the dynamics (i.e. carrying capacity, the specific growth rate at small densities or the strength of density regulation) or because of spatial variation in the effects of environmental stochasticity. To evaluate these, we used a hierarchical Bayesian approach to estimate parameters characterizing deterministic components and stochastic influences on population dynamics of eight species of ducks (mallard, northern pintail, blue-winged teal, gadwall, northern shoveler, American wigeon, canvasback and redhead (Anas platyrhynchos, A. acuta, A. discors, A. strepera, A. clypeata, A. americana, Aythya valisineria and Ay. americana, respectively) breeding in the North American prairies, and then tested whether these parameters varied latitudinally. 2. We also examined the influence of temporal variation in the availability of wetlands, spring temperature and winter precipitation on population dynamics to determine whether geographical gradients in population dynamics were related to large-scale variation in environmental effects. Population variability, as measured by the variance of the population fluctuations around the carrying capacity K, decreased with latitude for all species except canvasback. This decrease in population variability was caused by a combination of latitudinal gradients in the strength of density dependence, carrying capacity and process variance, for which details varied by species. 3. The effects of environmental covariates on population dynamics also varied latitudinally, particularly for mallard, northern pintail and northern shoveler. However, the proportion of the process variance explained by environmental covariates, with the exception of mallard, tended to be small. 4. Thus, geographical gradients in population dynamics of prairie ducks resulted from latitudinal gradients in both deterministic and stochastic components, and were likely influenced by spatial differences in the distribution of wetland types and shapes, agricultural practices and dispersal processes. 5. These results suggest that future management of these species could be improved by implementing harvest models that account explicitly for spatial variation in density effects and environmental stochasticity on population abundance.