Forest loss and treeless matrices cause the functional impoverishment of sapling communities in old‐growth forest patches across tropical regions

Abstract

1. Landscape-level disturbances, such as forest loss, can profoundly alter the functional composition and diversity of biotic assemblages. In fact, the landscape-moderated functional trait selection (LMFTS) hypothesis states that landscape-level disturbances may act as environmental filters that select a set of species with disturbance-adapted attributes while causing the loss of species with disturbance-sensitive attributes, ultimately compromising ecosystem functioning. However, the impact of landscape patterns on the functional composition and diversity of tropical regenerating trees (saplings) is unknown.2. Using a multiscale approach to identify the best spatial scale (i.e. the scale of effect), we tested the effect of forest cover, matrix openness and forest patch density (fragmentation) on functional composition and functional diversity of tree saplings in old-growth forest patches (n = 59) in three Mexican rainforest regions with different degree of deforestation. For 368 species and ~23,000 individuals, we compiled information from global and national databases on six functional traits related to seed dispersal and plant establishment and calculated their community abundance-weighted mean (CWM) and three complementary functional diversity indices.3. Forest loss and matrix openness reduced functional richness and evenness, but only in the two most deforested regions. Overall, fragmentation had contrasting effects on functional diversity and composition, but correlated negatively with some functional traits in the most deforested region. Importantly, in the regions with high-to-intermediate degree of deforestation, functional composition experienced major changes: maximum height, seed mass, fruit size and wood density decreased, and SLA increased, in forest patches surrounded by open matrices in highly deforested and fragmented landscapes. This caused a shift of community traits towards more disturbed-adapted attributes.

Variations in mitragynine content in the naturally growing Kratom (Mitragyna speciosa) population of Thailand

“…Although SPAD and SLA have been reported to be highly correlated with higher MG content at the seedling stage ( Zhang et al., 2022 ), the relationship was not significant for the mature trees sampled in our study ( Table 2 ). Additionally, SLA has been reported to be positively related with growth elsewhere, with higher values indicating a greater leaf ability to absorb sunlight for photosynthesis ( Arasa-Gisbert et al., 2022 ).…”

Accounting for trait variability and coordination in predictions of drought‐induced range shifts in woody plants

“…At the landscape scale, addressing the interaction of habitat configuration (e.g. fragmentation) with dispersal and resource‐use traits represents a powerful approach to capture the effects of disturbance legacies on the functional reorganization of communities (Arasa‐Gisbert et al ., 2022).…”

Indirect effects of habitat amount mediated by habitat configuration determine bat diversity at the landscape-scale in Peninsular Malaysia

“…The detrimental effects of habitat loss – a reduction in the habitat amount – on biodiversity have been widely acknowledged in the literature (Arasa-Gisbert et al 2022; Caro et al 2022; Sánchez-Bayo & Wyckhuys 2019). However, the effects of fragmentation are still widely debated (Miller-Rushing et al 2019).…”