Data from: Exotic species enhance response diversity to land-use change but modify functional composition

Two main mechanisms may buffer ecosystem functions despite biodiversity loss. First, multiple species could share similar ecological roles, thus providing functional redundancy. Second, species may respond differently to environmental change (response diversity). However, ecosystem function would be best protected when functionally redundant species also show response diversity. This linkage has not been studied directly, so we investigated whether native and exotic pollinator species with similar traits (functional redundancy) differed in abundance (response diversity) across an agricultural intensification gradient. Exotic pollinator species contributed most positive responses, which partially stabilized overall abundance of the pollinator community. However, although some functionally redundant species exhibited response diversity, this was not consistent across functional groups and aggregate abundances within each functional group were rarely stabilized. This shows functional redundancy and response diversity do not always operate in concert. Hence, despite exotic species becoming increasingly dominant in human-modified systems, they cannot replace the functional composition of native species.

尽管存在生物多样性丧失的情况，仍有两种主要机制可对生态系统功能起到缓冲保护作用。其一，多个物种可共享相似的生态位功能，从而形成功能冗余（functional redundancy）；其二，不同物种对环境变化的响应模式存在差异，即响应多样性（response diversity）。然而，当具备功能冗余的物种同时表现出响应多样性时，生态系统功能才能得到最佳保护。这一关联尚未被直接研究，因此我们开展了相关调查，以探究在农业集约化梯度下，具备相似功能性状（即功能冗余）的本土与外来传粉者物种，其种群丰度随该梯度的变化模式（即响应多样性）是否存在差异。研究结果显示，外来传粉者物种展现出最多的正向响应，这在一定程度上稳定了传粉者群落的总丰度。然而，尽管部分具备功能冗余的物种表现出了响应多样性，但这一现象在不同功能群间并不一致，且每个功能群内的总丰度也极少能得到稳定。这表明功能冗余与响应多样性并非总能协同发挥作用。因此，尽管外来物种在人为改造的生态系统中日益占据主导地位，但它们无法替代本土物种的功能组成。