Changing fire regimes in tropical montane cloud forests: a global synthesis

Abstract

Evidence for the occurrence of ®re in montane cloud forests on both historical and modern time scales has mounted in recent years, yet understanding of ®re regimes and the in¯uence of ®re on the dynamics of these ecosystems remains poor. This chapter discusses current knowledge of the frequency, severity, causes, and impacts of ®re in montane cloud forests worldwide as re¯ected in paleoecological records, recent ®eld studies, and satellite image analyses. Synthesis of the literature suggests that both human activities and climatic¯uctuations have played important and often interlinked roles in determining historical ®re regimes in montane cloud forests. In particular, increasing human populations and land use pressures surrounding cloud forest ecosystems, combined with more rapid climate warming this century due to anthropogenic forcing, is apparently leading to dramatic intensi®cation of ®re regimes in montane cloud forest regions. These changes may be accompanied by the transformation of cloud forests to more ®re-dependent plant communities (comprising species from adjacent ecosystems with more frequent ®re) that no longer have sucient resilience to recover from ®re and re-establish the original cloud forest vegetation. Management eorts need to focus on preventing ®res ignited by people for land use purposes from spreading into adjacent cloud forest areas, as well as actively involving local people and communities in ®re management and suppression eorts. INTRODUCTIONThe role of ®re as a disturbance factor in montane cloud forests (MCFs) has been largely neglected in the ecological literature due to the historically infrequent occurrence of ®re in these typically foggy, cool, and biodiverse ecosystems. Nevertheless,

Implications of fires on carbon budgets in Andean cloud montane forest: The importance of peat soils and tree resprouting

“…These fire impacts come associated with unaccounted for biomass burning emissions that we claim to be regionally important. This is particularly true considering that increasing human populations and land use pressures surrounding cloud forest ecosystems, combined with more rapid climate warming this century, are apparently leading to an intensification of fire regimes in montane cloud forest regions (see review at Asbjornsen and Wilcke, 2008).…”

“…200-300 years) (Weaver, 1989;Olander et al, 1998) and partly due to an extrapolation of fire susceptibility from wet lowland rainforest's research, where thin barks and lack of ecological adaptation to fire (such as resprouting strategies) result in large forest die-backs even with low fire intensities. Fire is, however, an important ecological disturbance factor on both historical and modern time scales in cloud forests (Asbjornsen and Wilcke, 2008;DiPasquale et al, 2008). While fire presence per se might not retreat the treeline, fire frequency quite likely does.…”

“…Although land use activities in TMCFs vary greatly depending on socio-economic and environmental drivers, a predominant pattern common to most TMCFs is the conversion to pasture (Young and León, 2007). Once established, pastures are generally burned annually to promote new growth of grasses and to prevent invasion by shrubs and trees (Asbjornsen and Wilcke, 2008). Both climate fluctuations and human activities play interlinked roles in determining fire regimes in TMCFs, with severe drought years such as 2005, leading to generalized fire in the tropical high Andes (>2000 masl) (Román-Cuesta et al, Personal observation) and montane ecosystems in Central America (Sherman et al, 2008).…”

Terrestrially Derivedn-Alkane δD Evidence of Shifting Holocene Paleohydrology in Highland Costa Rica

“…Fires require dry fuels to spread, and, whether set by humans or nature, depend on short-term climate and weather. The relationships between human activity, climate, and fire are complex and are only beginning to be documented in neotropical highlands (Asbjornsen and Wickel, 2009;Horn and Kappelle, 2009 …”

Subalpine Vegetation Change 14 Years after Feral Animal Removal on Windward East Maui, Hawai'i

“…Our research suggests this island TMCF has been resilient to the droughts and fire regimes of the past few millennia. However, TMCFs may cross ecological thresholds with more frequent/intense disturbance and experience state changes, promoting the loss of cloud forest area (e.g., Asbjornsen and Wickel, 2009). Understanding where this threshold is located for each TMCF is a research priority.…”