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，已被提议作为帮助物种追踪气候变化下适宜生境的工具。该方法面临诸多实际挑战，其中包括如何预判易位个体的投放点位。对于体型微小且无法移动的物种而言，这一问题尤为突出：这类物种的生存紧密依赖小型微环境条件，却与大尺度气候模型所预测的宏观环境条件存在明显脱钩。

为探究该问题，我们构建了基于野外调查的模型，以预测凯恩戈姆山脉（Cairngorm Mountains）内目标物种——枝状陆生北极-高山地衣（fruticose terricolous arctic-alpine lichen）雪黄扁枝衣（Flavocetraria nivalis）的分布位点。随后我们开展了该物种的实验性易位研究。我们构建的第二个模型采用了基于调查模型中具有统计学显著性的变量，但其仅能较为一般地预测接收样地的初始存活格局。然而，随着存活个体的分布愈发贴合适宜生境的分布特征，易位存活模型的拟合优度随时间推移逐步提升。此外，通过补充接收样地的微气候数据，模型的预测能力得到进一步增强。

综合与应用：我们的研究结果表明，对于那些对局部环境条件响应强烈、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颇具挑战。针对此类情况，将建模与专家判断相结合，并开展大规模移植操作，或可成为最大化辅助定植成功率的适宜方案。