Frequency of Occurrence and Population-Dynamic Consequences of Different Forms of Density-Dependent Emigration
Frequency of Occurrence and Population-Dynamic Consequences of Different Forms of Density-Dependent Emigration
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DOI：
10.1086/708156
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发表时间：
2020-05-01
影响因子：
2.9
通讯作者：
Cronin, James T.
中科院分区：
文献类型：
--
作者：
Harman, Rachel R.;Goddard, Jerome, II;Cronin, James T.
迁移是影响物种局部、区域和大尺度动态的基本过程。生态学的范式观点是移民是密度无关的（DIE）或正密度依赖的（1DDE）。然而，替代形式在生物学上是合理的，包括阴性（2DDE）、U形（uDDE）和驼峰形（hDDE）形式。我们回顾了经验文献，以评估不同形式的密度依赖性移民的频率，以及这种形式是否取决于方法。我们还开发了一个反应扩散模型来说明不同形式的DDE如何影响斑块水平的种群持续性。我们发现了145项研究，大多数代表DIE（30%）和1DDE（36%）。然而，我们也经常发现2DDE（25%）和非线性DDE（9%）的证据，包括1例uDDE和2例hDDE。非线性DDE检测可能会受到使用较少密度水平和较小密度范围的阻碍。根据我们的模型，DIE和1DDE促进稳定和持久的种群。uDDE和2DDE产生的Allee效应，减少最小补丁大小。最后，2DDE和hDDE模型产生了双稳态，允许在较低密度下建立种群。我们的结论是，移民过程中可以是一个不同的功能，密度的性质和替代DDE形式可以有重要的后果，人口动态。
Emigration is a fundamental process affecting species' local, regional, and large-scale dynamics. The paradigmatic view in ecology is that emigration is density independent (DIE) or positive density dependent (1DDE). However, alternative forms are biologically plausible, including negative (2DDE), U-shaped (uDDE), and hump-shaped (hDDE) forms. We reviewed the empirical literature to assess the frequency of different forms of density-dependent emigration and whether the form depended on methodology. We also developed a reaction-diffusion model to illustrate how different forms of DDE can affect patch-level population persistence. We found 145 studies, the majority representing DIE (30%) and 1DDE(36%). However, we also regularly found 2DDE (25%) and evidence for nonlinear DDE(9%), including one case of uDDE and two cases of hDDE. Nonlinear DDE detection is likely hindered by the use of few density levels and small density ranges. Based on our models, DIE and 1DDE promoted stable and persistent populations. uDDE and 2DDE generated an Allee effect that decreases minimum patch size. Last, 2DDE and hDDE models yielded bistability that allows the establishment of populations at lower densities. We conclude that the emigration process can be a diverse function of density in nature and that alternative DDE forms can have important consequences for population dynamics.