Context

Determining the appropriate scale at which to study species’ interactions with their environment is a great challenge.

Objective

We investigated the spatial extent at which landscape structure affects the occurrence of four species of terrestrial mammalian herbivores in the Brazilian savannas and examined whether those scales could be explained by species ecological traits and how forest habitat was operationally defined.

Methods

Using maps of forest cover, camera trapping and occupancy modelling, we determined the relations between three landscape metrics (percentage of forest cover, patch density and edge density) and the occurrence of four species. To determine the optimal scale of effect for each species, we computed landscape metrics at different spatial extents (from 0.5 to 10 km radius) from camera trap locations and for three forest maps, each using different operational definitions of a forest pixel: minimum of tree cover of 25, 50 or 75%.

Results

The occupancy models revealed scales of effect of 0.5 to 2 km with the scale of effect being similar among three of the species. However, the probability of a scale of effect being detected depended upon how forest is operationally defined, being greater when forest was defined with greater tree cover, particularly for forest-specialist species.

Conclusions

Besides biological traits, the way habitat is operationally defined shapes our ability to detect the scale of effects. Thus, it is necessary not to adopt a multi-scale approach, but also to use multiple operational definitions of habitat, considering particularities of how each species interact with their environment.

中文翻译：

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影响范围取决于森林覆盖的业务定义-来自巴西大草原陆生哺乳动物的证据

语境

确定研究物种与其环境相互作用的合适规模是一个巨大的挑战。

目的

我们调查了景观结构影响巴西热带稀树草原上四种陆生哺乳动物食草动物发生的空间范围，并研究了这些尺度是否可以通过物种生态特征来解释，以及如何对森林栖息地进行有效定义。

方法

使用森林覆盖图，相机诱捕和占用模型，我们确定了三种景观指标（森林覆盖率，斑块密度和边缘密度）与四种物种的发生之间的关系。为了确定每种物种的最佳效果规模，我们从相机陷阱位置和三张森林地图（分别使用森林像素的不同操作定义）计算了不同空间范围（半径从0.5到10 km）的景观度量。覆盖率是25％，50％或75％。

结果

占用模型表明影响范围为0.5至2 km，其中三个物种的影响范围相似。但是，检测到影响范围的可能性取决于如何对森林进行操作性定义，而当森林被定义为具有更大的树木覆盖率时，则更大，特别是对于森林专家物种而言。

结论

除生物学特性外，在操作上定义栖息地的方式还影响着我们检测影响范围的能力。因此，有必要不采用多尺度方法，而要考虑到每个物种如何与环境相互作用的特殊性，而要使用多种栖息地的操作性定义。