دانلود رایگان مقاله اقلیم های جدید: مسیرهای تغییر اقلیم فراتر از مرزهای سیستم مدیریت دانش جنگل های بریتیش کلمبیا

ABSTRACT

The non-stationary climates of the 21st century are compelling forest managers to seek non-local species, provenances, and silvicultural regimes that are better suited to the anticipated future climates of their operating areas. Ideally, forest managers can source this information from climate analogs within their jurisdictions, but the emergence of unfamiliar climates is a distinct possibility with particular challenges. Here, we present an assessment of the emergence of mid-21st-century climates with no analog in the 20th-century climates of British Columbia (BC), and the extent to which these novel climates are described by climate analogs elsewhere in North America. We use a recently developed linear method of novel climate detection in parallel with Random Forest classification to evaluate the robustness of novel climate inferences. Our results suggest that a majority of the province’s area will remain free of novel climates over this time period, and therefore that BC’s ecological knowledge system, the Biogeoclimatic Ecosystem Classification, can remain the dominant source of climate analogs for mid-21st-century forest management planning horizons. Nevertheless, we detected a robust pattern of climates that are novel to BC in mid-21st-century climate projections at low elevations in the coastal, southern interior, and northeastern regions of the province. There appears to be potential to inform forest management in some of these novel climates with analogs from adjacent states and provinces. We demonstrate that extrapolations into novel climates typically understate the magnitude of climate change and modeling uncertainty, creating a false impression of robust predictions in locations where model performance is poorest. By identifying portions of their landscapes that are prone to emergence of novel climates, forest managers can avoid management errors and prioritize the search for analogs beyond the boundaries of their knowledge systems.

4.4. The limits to adaptation in unfamiliar climates

The accumulation of local ecosystem management regimes, and an understanding of the range of conditions over which they could be successfully applied, was one of the defining accomplishments of 20thcentury forest management. This structuring of ecological knowledge into climatic and edaphic classes based on the concept of ecological equivalence is exemplified by BEC, which provides a framework to define limits to the spatial transferability of management regimes, genetic resources, and natural resources legislation. Climate change undermines a core underpinning of this knowledge base—that the future will resemble the past on the timescales over which forests are managed. Climate analogs can assist forest managers with redeploying their hard-won knowledge across the changing climates of their land base, and with sourcing non-local management strategies for the locally unfamiliar climates of the 21st century. However, a distinct problem of managing ecosystems in a non-stationary climate is that predicted ecosystem responses, and the applicability of knowledge derived from climate analogs, cannot be verified except by waiting for events to unfold (Rastetter, 1996), at which point the predictions are moot. In addition, the future state of local climates is subject to many uncertainties stemming from global climate models (Deser et al., 2012; Knutti and Sedláček, 2012). These factors constrain the time horizon over which forest managers can place confidence in guidance from climate analogs.