Leaf functional traits predict shade tolerant tree performance in cloud forest restoration plantings

Abstract

Abstract Restoration of tropical montane cloud forest (TMCF) landscapes is urgently required. Assisting the regeneration of endangered and shade tolerant tree species is essential for both the recovery of this vulnerable group and of ecological processes. However, there is limited species‐specific information regarding tree performance under different disturbance conditions with which to implement effective interventions. We assessed the performance of shade tolerant tree seedlings in restoration plantings under different disturbance settings and determined whether leaf mass area (LMA) and leaf dry mass content (LDMC)—functional traits typically associated with resource capture or stress tolerance—could serve as predictors of survival and growth among species. Since conservative leaf morphological traits can maximize survival, we expected species with higher LMA and LDMC to present higher survival. For a set of eight native cloud forest species, a total of 2,202 seedlings were planted in four pastures, five secondary forests and three forests subjected to traditional selective logging, in TMCF landscapes in Eastern Mexico. Seedling survival was high after 3 years: 62% in pastures, 80% in secondary forests and 88% in logged forests. Growth rates were lowest in pastures, followed by secondary forests and highest in logged forests. LMA was a strong predictor of seedling survival in all of the environments; tree species with higher LMA presented greater survival. LDMC was related to seedling survival in the three environments, although to a lesser extent than LMA. In the pastures, higher LMA and LDMC were linked to lower growth. Synthesis and applications. This study supports the potential of shade tolerant tree species in restoration efforts to assist the recovery of this important functional group and to accelerate succession across altered environments. Our results support the notion that conservative leaf functional traits are linked to a higher probability of survival, not only in the shaded understorey, but also under high solar radiation in transformed habitats. Leaf mass area (LMA) in particular is a reliable predictor of seedling survival for shade tolerant species. Species selection based on LMA could thus improve restoration initiative outcomes: tree species with high LMA present higher survival probability and can be introduced into pastures, secondary forests and selectively logged forests.