The memory of spatial patterns: changes in local abundance and aggregation in a tropical forest
The memory of spatial patterns: changes in local abundance and aggregation in a tropical forest
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DOI：
10.1890/11-1004.1
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发表时间：
2012-07-01
期刊：
影响因子：
4.8
通讯作者：
Murrell, David J.
中科院分区：
文献类型：
--
作者：
Fluegge, Anton J.;Olhede, Sofia C.;Murrell, David J.
种群当前的空间格局是个体先前出生、死亡和扩散事件的结果。我们提出了一个简单的模型，然后进行比较分析，物种丰富的植物群落，以显示如何目前的空间聚集的人口可能会举行最近的人口动态信息。之前的研究表明，局部限制的种子传播往往会导致不太丰富的种群比更丰富的种群更强的聚集。与此相反，很少有人知道如何在一个物种的本地丰富的变化可能会影响个人的空间分布。如果一个物种内的聚集水平在某种程度上取决于该物种的丰度，那么丰度的变化应导致随后聚集的变化。然而，空间格局的总体变化依赖于许多个体的出生和死亡事件，死亡或出生的过剩可能会对聚集产生短期影响，这与丰度变化所预测的长期变化相反。因此，聚集的变化可能落后于丰度的变化，因此，当前的聚集可能包含有关最近种群动态的信息。使用基于个体的模拟模型与当地的扩散和密度依赖的竞争，我们表明，平均而言，最近增长的人口应该更聚集比收缩人口相同的当前本地丰度。我们测试了这一假设，从长期的热带雨林地块的个人使用的空间数据，并找到支持这种关系的树冠树木，但不是在林下植物和灌木物种。在此基础上，我们认为，目前的空间聚集是一个重要的特征，包含最近的变化信息，在当地的丰度，并可能适用于分类组的分散是有限的，种内聚集观察。
The current spatial pattern of a population is the result of previous individual birth, death, and dispersal events. We present a simple model followed by a comparative analysis for a species-rich plant community to show how the current spatial aggregation of a population may hold information about recent population dynamics. Previous research has shown how locally restricted seed dispersal often leads to stronger aggregation in less abundant populations than it does in more abundant populations. In contrast, little is known about how changes in the local abundance of a species may affect the spatial distribution of individuals. If the level of aggregation within a species depends to some extent on the abundance of the species, then changes in abundance should lead to subsequent changes in aggregation. However, an overall change of spatial pattern relies on many individual birth and death events, and a surplus of deaths or births may have short-term effects on aggregation that are opposite to the long-term change predicted by the change in abundance. The change in aggregation may therefore lag behind the change in abundance, and consequently, the current aggregation may hold information about recent population dynamics. Using an individual-based simulation model with local dispersal and density-dependent competition, we show that, on average, recently growing populations should be more aggregated than shrinking populations of the same current local abundance. We tested this hypothesis using spatial data on individuals from a long-term tropical rain forest plot, and find support for this relationship in canopy trees, but not in understory and shrub species. On this basis we argue that current spatial aggregation is an important characteristic that contains information on recent changes in local abundance, and may be applied to taxonomic groups where dispersal is limited and within-species aggregation is observed.