Managing climate change effects on relic forest ecosystems: A program for Lebanese Cedar

Abstract

The effect of climate change on forests varies with the geographical zone and climatic conditions of countries and regions. While climatic records for the Western Mediterranean show slight trends towards warmer and drier conditions over the last century, parts of the Eastern Mediterranean have experienced cooler and wetter conditions. Mediterranean forests are likely to be impacted by these changes, which could reduce their mitigation potential. If climate change occurs faster than new ecosystem structure and function can be developed, then the historical relationships between animal, plant and climatic conditions may not be reestablished and biological diversity will be reduced. During the last three decades, an expansion of the geographic range of major forest insect pests, caused by increased winter temperatures, have been observed worldwide. In Lebanon, changes in climatic conditions are linked with an altitudinal shift in bioclimatic zones. Cedar forest reserves, typical of the Montane-Mediterranean zone, recognized worldwide for their biological, cultural, historical and social value have been facing major threats. An alarming indicator appeared in these forests in the late 1990s where a web-spinning sawfly affected 70% of one of the largest populations of Cedar (Cedrus libani A.) forests in Lebanon. The newly-discovered insect, Cephalcia tannourinensis Chevin, now threatens the survival of several important Cedar forests, namely the Tannourine Cedar Forest Nature Reserve, the Hadeth El Jebbeh Forest, and the Bsharry Forest. Recognizing the value of these relic ecosystems, national stakeholders have been proactive in attracting international funds to conserve them, monitor their flora and fauna diversity and to remediate and prevent climate change effects at both national and regional levels. Although the pest management program was satisfactory, work on the sawfly's biology revealed that it would increase again rapidly unless climate change effects could be mitigated. The definition of adequate mitigation and adaptation measures requires the development of monitoring programmes integrating biotic and abiotic parameters. This article highlights the importance of these Cedar forests and the strategy adopted for managing the pest outbreak through the implementation of an integrated management program. It presents a monitoring plan for Cedar forest ecosystems under the effects of climate change.