Predicting the current and future distribution of pine woodland specialist plants in the Cairngorms National Park

Abstract

The Caledonian pine forests of Scotland have declined significantly over the past century largely due to clearance for timber, fuel and grazing land. Approximately 1% of these native pinewoods remain from their historic extent, with a stronghold in the Cairngorms National Park. Creeping Lady’s-Tresses Goodyera repens (L.) R. Br., One-Flowered Wintergreen Moneses uniflora (L.) A. Gray and Twinflower Linnaea borealis L. favour this habitat, meaning that the clearance of pine woodland has resulted in widespread declines. There are multiple plantation schemes underway in the Cairngorms to reforest the Highlands, such as Cairngorms Connect, partly with the intent of assisting the recovery of pine woodland specialists. This study uses Maximum Entropy modelling (MaxEnt) to create species distribution models (SDMs), firstly to predict the current distribution for these species; thus, enabling land managers in the Cairngorms to target surveys with the hope of finding new populations. Secondly, future distribution models are created using different emissions scenarios to predict the regions of maximum habitat suitability for the study species, with the aim of visualising where pine woodland should be planted to ensure long-term habitat viability. The results showed that there are regions in the north and east of the Cairngorms which have the highest habitat suitability, currently and in the future. The creation of habitat corridors between these two regions should be a priority to prevent isolation between populations of pine woodland specialists. The high emissions pathway could increase the likelihood of isolation by significantly decreasing the habitat suitability between the most suitable areas.