Climatic Disequilibrium Threatens Conservation Priority Forests

Brian Huntley,Jonathan Bennie,Judy R.M Allen,Paul A Miller,Yvonne C Collingham,Andrew J Suggitt

doi:10.1111/conl.12349

Abstract

AbstractWe test the hypothesis that climatic changes since 1800 have resulted in unrealized potential vegetation changes that represent a “climatic debt” for many ecosystems. Caledonian pinewoods, an EU priority forest type, are used as a model system to explore potential impacts of two centuries of climatic change upon sites of conservation importance and surrounding landscapes. Using methods that estimate topographic microclimate, current and preindustrial climates were estimated for 50 m grid cells and simulations made using a dynamic vegetation model. Core Caledonian pinewood areas are now less suitable for growth of pine and more favorable for oak than in 1800, whereas landscapes as a whole are on average more favorable for both. The most favorable areas for pine are now mainly outside areas designated to conserve historical pinewoods. A paradigm shift is needed in formulating conservation strategies to avoid catastrophic losses of this habitat, and of many others globally with trees or other long‐lived perennials as keystone species.

Highlights

Biodiversity conservation strategies often focus upon site-based conservation of habitats characterized by their vegetation composition (e.g., EU Habitats and Species Directive; Council of the European Union 1992)
The greatest relative decrease was in the Rhidorroch pinewoods of the northernmost landscape, whereas the largest relative increase was for the Rannoch landscape, the most southerly site with the highest mean simulated P. sylvestris aNPP
At Black Wood of Rannoch, mean aNPP of the 5% of 50 m grid cells with the highest P. sylvestris aNPP values was only marginally lower for present than preindustrial conditions, indicating that small areas within the Special Areas of Conservation (SACs) remain favourable for P. sylvestris

Summary

Introduction

Biodiversity conservation strategies often focus upon site-based conservation of habitats characterized by their vegetation composition (e.g., EU Habitats and Species Directive; Council of the European Union 1992). Numerous studies have addressed species’ potential responses to projected future climatic changes, and the implications of these responses for biodiversity conservation strategies (e.g., Araujo et al 2004; Hole et al 2011; Bagchi et al 2013). Rapid climatic change, began two centuries ago in some regions, driven by increases in greenhouse gas concentrations since 1750 (Hartmann et al 2013). These climatic changes have elicited various species’ responses, including geographical range shifts (Parmesan 2006; Mason et al 2015). To-date, potential vegetation responses to historical climatic changes have received little attention. Given the inertia of plant communities, most of which are dominated by long-lived species (Smith 1965), and the importance of relatively infrequent disturbance events in facilitating such communities’ responses to climatic change (Bradshaw & Zackrisson 1990; Prentice et al 1991), it is possible that much of Earth’s vegetation has accumulated a climatic debt

Methods

Results

Conclusion