Data from: Tiny niches and translocations: the challenge of identifying suitable recipient sites for small and immobile species

Assisted colonisation, one form of species translocation, has been proposed as a tool for helping species to track suitable conditions in a changing climate. There are considerable practical challenges associated with it, including predicting where to place translocated individuals. This problem may be particularly big for small and immobile species, where small-scale micro-environmental conditions de-couple them from environmental conditions as projected in large-scale climate models.
To investigate this problem we developed a survey-based model to predict the occurrence of our target species, the fruticose terricolous arctic-alpine lichen, Flavocetraria nivalis, within the Cairngorm Mountains.
We then undertook an experimental translocation of this species. A second model, using variables that were significant in the survey-based model, was only fair at predicting the initial pattern of survival at the recipient site.
However, model fit of the translocation survival model improved over time as the distribution of surviving individuals more accurately reflected the distribution of suitable environmental conditions. In addition, model predictive power increased with the addition of data on micro-climatic conditions at recipient plots.
Synthesis and applications. Our results demonstrate that, for species which respond strongly to local environmental conditions, are immobile and, to some extent, decoupled from larger-scale climates, it may be difficult to build a priori accurate predictive models of habitat suitability. In these cases, a combination of modelling and expert judgement, along with the movement of substantial numbers of transplants, may be the appropriate options for maximising the success of assisted colonisation.

辅助定植（assisted colonisation）作为物种易位（species translocation）的一种形式，已被提议作为协助物种在气候变化背景下追踪适宜生境的技术手段。该方法面临诸多实际挑战，其中包括如何确定易位个体的投放位点。这一问题对于体型微小且无法移动的物种尤为突出，因为这类物种的局域微环境条件与大尺度气候模型所预测的环境条件相互脱钩。

为探究该问题，我们开发了基于调查的模型，以预测目标物种——枝状土生北极-高山地衣雪黄髓衣（Flavocetraria nivalis）在凯恩戈姆山脉（Cairngorm Mountains）内的发生情况。

随后我们开展了该物种的实验性易位。基于调查模型中具有统计学显著性的变量所构建的第二个模型，仅能较为一般地预测接收位点的初始存活模式。

然而，随着存活个体的分布更精准地匹配适宜生境的分布，易位存活模型的拟合优度随时间推移逐步提升。此外，加入接收样地的微气候数据后，模型的预测能力得到显著增强。

综合与应用。我们的研究结果表明，对于强烈响应局域环境条件、无法移动且在一定程度上与大尺度气候脱钩的物种而言，构建先验准确的生境适宜性预测模型可能颇具难度。在此类场景下，结合建模与专家判断，辅以大量移植个体的迁移，或许是最大化辅助定植成功率的可行方案。