SPATIAL ECOLOGY OF CACTUS BUGS: AREA CONSTRAINTS AND PATCH CONNECTIVITY
SPATIAL ECOLOGY OF CACTUS BUGS: AREA CONSTRAINTS AND PATCH CONNECTIVITY
复制标题
仙人掌虫子的空间生态：区域限制和斑块连通性
作者：
R. Schooley;J. Wiens
了解景观结构对细分栖息地中生物分布的影响是空间生态学和保护生物学的核心。我们研究了合适的栖息地斑块和干预基质如何影响仙人掌蝽（Chelinidea vittiger）在其天然斑块寄主植物平原仙人掌（Opuntia polyacantha）上的发生率和丰度。我们比较了 C. vittiger 在美国科罗拉多州两个具有不同基质特性的景观中的三个生命阶段的响应。斑块面积和 C. vittiger 丰度表现出我们用分位数回归估计的限制因素关系。在所有生命阶段和景观中，斑块中的 Chelinidea vittiger 密度与斑块面积呈负相关。我们的结果支持了“匹配不足假设”的预测，该假设表明对资源斑块的有限了解是丰度模式的决定因素之一。占有率和丰度的多元回归模型表明（1）解释方差的大小很大程度上取决于测量的响应变量和昆虫的生命阶段，（2）斑块连通性指标在丰度模型中比斑块中存在与不存在有更多支持，（3）在大多数丰度模型中，斑块面积与斑块连通性具有交互作用，（4）连通性的“矩阵问题”测量在包含时仅获得混合支持 具有异质矩阵的景观的丰富模型。仅包含基本集合种群模型中两个优先变量（斑块面积和斑块连通性）的模型不足以理解 C. vittiger 在斑块景观中的分布模式。
Understanding the effects of landscape structure on the distribution of or- ganisms in subdivided habitat is central to spatial ecology and conservation biology. We investigated how suitable habitat patches and the intervening matrix influenced the incidence and abundance of cactus bugs (Chelinidea vittiger) on their naturally patchy host plant, plains prickly pear (Opuntia polyacantha). We compared responses of three life stages of C. vittiger on two landscapes with different matrix properties in Colorado, USA. Patch area and abundances of C. vittiger exhibited a limiting-factor relationship that we estimated with quantile regression. Chelinidea vittiger density in patches was negatively related to patch area for all life stages and landscapes. Our results supported predictions from the "under- matching hypothesis," which suggests that limited knowledge of resource patches is one determinant of abundance patterns. Multiple regression models of occupancy and abundance indicated that (1) the amount of explained variance depended greatly on the measured response variable and on the life stage of the insect, (2) metrics of patch connectivity had more support in models of abundance than of presence-absence in patches, (3) patch area had an interactive effect with patch connectivity in most abundance models, and (4) a "matrix-matters" measure of connectivity received only mixed support when included in abundance models for a landscape with a heterogeneous matrix. A model that included only the two priority variables in basic metapopulation models (patch area and patch con- nectivity) was insufficient for understanding distribution patterns of C. vittiger in patchy landscapes.