Tropical Rainforests and Agroforests under Global Change

Book excerpt: not only for land use systems that depend on the regular supply of rain or irrigation water but also for the future development of natural rainforests as drought stress has been shown to a?ect tree growth and species composition in old-growth forests (Wright 1991, Walsh and Newbery 1999, Engelbrecht et al. 2007). A drought experiment conducted in a cacao agroforestry plantation showed that this plantation was surprisingly resilient to an induced drought of more than a year (Schwendenmann et al. 2009). However, droughts can have a strong impact on household incomes from agriculture, they strongly a?ect the vulnerability to poverty and thus have to be analyzed as important exogenous shocks to households, forcing them to adjust their behaviour and develop strategies to cope with these problems. The stability of rainforest margins is a critical factor in the protection of tropical rainforests (Tscharntke et al. 2007). At present, however, rainf- est margins in many parts of the tropics are far from stable, both in soc- economic and in ecological terms. For example, protected areas may attract, rather than repel, human settlement, which may be due to international donor investment in national conservation programs (Wittemeyer et al. 2008). An alternative hypothesis is that protected areas might be compromised if leakage takes place, that is, if impacts that would take place inside the restricted area are displaced to a nearby, undisturbed area (Ewers and Rodrigues 2008).