Heterogeneity in quantity and quality of resources provided in the urban matrix may mitigate adverse effects of urbanization intensity on the structure of biotic communities. To assess this we quantified the spatial variation in butterfly richness and abundance along an impervious surface gradient using three measures of urban matrix quality: floral resource availability and origin (native vs. exotic plants), tree cover, and the occurrence of remnant habitat patches. Butterfly richness and abundance were surveyed in 100 cells (500 × 500 m), selected using a random‐stratified sampling design, across a continuous gradient of imperviousness in Melbourne, Australia. Sampling occurred twice during the butterfly flight season. Occurrence data were analyzed using generalized linear models at local and mesoscales. Despite high sampling completeness, we did not detect 75% of species from the regional species pool in the urban area, suggesting that urbanization has caused a large proportion of the region's butterflies to become absent or extremely rare within Melbourne's metro‐area. Those species that do remain are largely very generalist in their choice of larval host plants. Butterfly species richness and abundance declined with increasing impervious surface cover and, contrary to evidence for other taxa, there was no evidence that richness peaked at intermediate levels of urbanization. Declines in abundance appeared to be more noticeable when impervious surface cover exceeded 25%, while richness declined linearly with increasing impervious surface cover. We find evidence that the quality of the urban matrix (floral resources and remnant vegetation) influenced butterfly richness and abundance although the effects were small. Total butterfly abundance responded negatively to exotic floral abundance early in the sampling season and positively to total floral abundance later in the sampling season. Butterfly species richness increased with tree cover. Negative impacts of increased urbanization intensity on butterfly species richness and abundance may be mitigated to some extent by improving the quality of the urban matrix by enhancing tree cover and the provision of floral resources, with some evidence that native plants are more effective.

中文翻译：

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蝴蝶的丰富度和丰度沿不渗透性和基质质量的重要性梯度变化。

在城市矩阵中提供的资源数量和质量的异质性可以减轻城市化强度对生物群落结构的不利影响。为了评估这一点，我们使用三种衡量城市基质质量的指标，量化了沿不透水表面梯度的蝴蝶丰富度和丰度的空间变化：花卉资源的可用性和来源（本地植物与外来植物），树木覆盖以及残余栖息地斑块的发生。在澳大利亚墨尔本的不透水连续梯度范围内，采用随机分层抽样设计在100个细胞（500×500 m）中调查了蝴蝶的丰富度和丰度。在蝴蝶飞行季节采样两次。使用局部和中尺度的广义线性模型分析了发生数据。尽管采样完整性很高，我们没有从市区的区域物种库中检测到75％的物种，这表明城市化进程已导致该地区很大一部分蝴蝶在墨尔本都会区内变得不复存在或极为罕见。在选择幼虫寄主植物时，那些仍然存在的物种在很大程度上非常笼统。蝴蝶物种的丰富度和丰度随着不透水表面覆盖率的增加而下降，并且与其他类群的证据相反，没有证据表明丰富度在城市化的中等水平达到顶峰。当不透水的表面覆盖率超过25％时，丰度的下降似乎更为明显，而随着不透水的表面覆盖率的增加，丰富度呈线性下降。我们发现有证据表明，尽管影响很小，但城市基质（花卉资源和残余植被）的质量影响了蝴蝶的丰富度和丰度。在采样季节的早期，蝴蝶的总丰度对奇异花的丰度有负面反应，而在采样季节的后期，总蝴蝶的丰度对总花的丰度有正面反应。蝴蝶物种丰富度随树被覆盖而增加。通过增强树木的覆盖率和提供花卉资源来改善城市基质的质量，可以在一定程度上减轻城市化强度增加对蝴蝶物种丰富度和丰度的负面影响，并且有证据表明，本地植物更有效。在采样季节的早期，蝴蝶的总丰度对奇异花的丰度有负面反应，而在采样季节的后期，总蝴蝶的丰度对总花的丰度有正面反应。蝴蝶物种丰富度随树被覆盖而增加。通过增强树木的覆盖率和提供花卉资源来改善城市基质的质量，可以在一定程度上减轻城市化强度增加对蝴蝶物种丰富度和丰度的负面影响，并且有证据表明，本地植物更有效。在采样季节的早期，蝴蝶的总丰度对奇异花的丰度有负面反应，而在采样季节的后期，总蝴蝶的丰度对总花的丰度有正面反应。蝴蝶物种丰富度随树被覆盖而增加。通过增强树木的覆盖率和提供花卉资源来改善城市基质的质量，可以在一定程度上减轻城市化强度增加对蝴蝶物种丰富度和丰度的负面影响，并且有证据表明，本地植物更有效。