Hurricanes increase tropical forest vulnerability to drought

Abstract

Rapid changes in climate and disturbance regimes, including droughts and hurricanes, are likely to influence tropical forests, but our understanding of the compound effects of disturbances on forest ecosystems is extremely limited. Filling this knowledge gap is necessary to elucidate the future of these ecosystems under a changing climate. We examined the relationship between hurricane response (damage, mortality, and resilience) and four hydraulic traits of 13 dominant woody species in a wet tropical forest subject to periodic hurricanes. Species with high resistance to embolisms (low P₅₀ values) and higher safety margins ( ${\text{SM}}_{P_{50}}$ ) were more resistant to immediate hurricane mortality and breakage, whereas species with higher hurricane resilience (rapid post-hurricane growth) had high capacitance and P₅₀ values and low ${\text{SM}}_{P_{50}}$ . During 26 yr of post-hurricane recovery, we found a decrease in community-weighted mean values for traits associated with greater drought resistance (leaf turgor loss point, P₅₀ , ${\text{SM}}_{P_{50}}$ ) and an increase in capacitance, which has been linked with lower drought resistance. Hurricane damage favors slow-growing, drought-tolerant species, whereas post-hurricane high resource conditions favor acquisitive, fast-growing but drought-vulnerable species, increasing forest productivity at the expense of drought tolerance and leading to higher overall forest vulnerability to drought.

Keywords: Hurricane Hugo; P50 xylem optical vulnerability curves; coastal tropical forests; cyclonic storm; forest succession; plant hydraulics; plant-climate interactions; tropical trees and palms.