Forests in mountainous regions cover more than 9 million square kilometres of the Earth’s surface, comprising 23% of the world’s total forest cover (Price et al. 2010). Mountain Forests play a disproportionate role for global ecosystem services; for example, they provide 60–80% of the world’s freshwater resources despite covering only 24% of the Earth’s surface (Viviroli et al. 2007). They provide goods and services crucial for livelihoods of both highland and lowland human communities (Price et al. 2010).
Climate change in mountain ecosystems has a particularly high potential to cause severe declines in provisioning of ecosystem services (Beniston, 2003, Nogues-Bravo et al. 2007). Combined with their location in a region forming a tipping element in the Earth’s climate system and having low economic resilience, Himalayan nations are particularly prone to severe consequences of climate change (Xu et a. 2009). This is true for Bhutan, one of the least developed land-locked mountainous countries with about 38% of the rural population living below the poverty line (10th Five Year Plan (FYP), GNH Commission 2008).
Forests are the dominant land use type in Bhutan, comprising 70% of the country’s area. Bhutan has committed to maintaining at least 60% forest cover in perpetuity (Constitution, Kingdom of Bhutan). The high forest cover, however, has to be interpreted with care: There is no country-wide forest inventory on the condition of the areas which were classified as forest. Results and experiences from all over the world underline the fact that forest cover alone is an insufficient indicator for sound and sustainable forest management and conservation. This is corroborated for Bhutan by numerous reports on degradation of forests in areas adjacent to villages and also on a lack of tree regeneration after commercial logging (e.g. Moktan 2008, Wangchuk 2003). This holds particularly true for specific forest types, like forests with Quercus semecarpifolia, where overutilization even led to a ban of the use of oak wood as fuelwood.
Climate change effects on plant communities are predicted to result in species range shifts, with concomitant changes in ecosystem services (Lenoir et al. 2008, Pucko et al. 2011), occurring through catastrophic regime shifts (sensu Scheffer and Carpenter 2003) or altered disturbance regimes (e.g. Westerling et al. 2006, Kurz et al. 2008). Such altered disturbance regimes like increased fire frequencies and intensities, increased storm frequencies, altered population dynamics of biotic disturbance agents and novel stressors like invasive species put strong threats to the resilience to Himalayan forests. Warming trends in the Himalayas are reported to be stronger than for other regions (IPCC 2007) and show a consistent trend for the last century (Yao et al. 2006). Isotope (δ18O) chronologies in Nepal suggest an increasing aridity over the past two centuries in the Himalayas (Sano et al 2011). Cook et al. (2010) developed a Monsoon Asia Drought Atlas with spatial information on megadroughts – annual or supra-annual monsoon failures in South Asia together with coarse scale climate proxies related to these events. These works underline the potential importance of future drought phenomena on ecosystems and livelihoods in this region. Drought is one of the major causes for climate change induced tree mortality (Adams et al. 2009). Drought stress is likely to synergistically increase the risk of biotic disturbances like bark beetles in coniferous forests as well as the frequency and intensity of forest fires (Westerling et al. 2006).
Developing and adopting a strategy for increasing the resilience against climate change risks is a major determinant for the future consequences of climate change on livelihoods (e.g. Lobell et al. 2008). Particularly for countries like Bhutan with very steep, erodible terrain and low economic resilience, this holds also true for forests. Potential changes in disturbance regimes need to be characterized and knowledge of how to increase resilience of the different forest ecosystems is critically important. This includes better understanding of stress tolerances, including belowground functional biodiversity associated with the main tree species.
With the proposed project, the potential for climate adaptation and mitigation measures in Bhutanese forests will be determined and concrete activities will be initiated to increase the resilience of forests to future changes (e.g. increase species diversity in early successional monospecific forests). With anticipated changes in climate and related stress responses, including increased competition for water and reduced production of defensive compounds in trees, susceptibility to other synergistic disturbances, such as fire, pathogens, and insects, is also likely to increase. Interactions among these are likely to create feedback relationships by which both rates of ecosystem change are accelerated and novel (or unprecedented) trajectories of change created (Aber et al. 2001). Understanding these synergistic interactions, future potential susceptibilities, and the likelihood of alternate pathways of change is therefore central to this project.
Forest restoration strategies and activities for increasing carbon stocks as well as combating species losses, particularly on degraded lands, will be developed using innovative participative tools. Bamboo species have recently been identified as plants with particularly high climate change adaptation potential and have been included in carbon trade markets (e.g. China). In Bhutan, 31 bamboo native species are found. They often naturally dominate the understory of forests. The potential of these species for climate change adaptation and ecosystem restoration, protection against erosion and buildup of carbon storage will be characterized in this project.
A strong focus on capacity building will guarantee long term sustainability of inputs and ownership of knowledge and activities. The project will provide information for the Forest Carbon Partnership Facility (FCPC) process in Bhutan. The Watershed Management Division which is a partner in this project was mandated to apply for the membership. The process will be facilitated through results from work packages 1, 2 and 3 and will be directly aided by work package 5 and 6.