Species Richness, Forest Structure, and Functional Diversity During Succession in the New Guinea Lowlands

Abstract

Much of the world's tropical forests have been affected by anthropogenic disturbance. These forests are important biodiversity reservoirs whose diversity, structure and function must be characterized across the successional sequence. We examined changes in structure and diversity along a successional gradient in the lowlands of New Guinea. To do this, we measured and identified all stems ≥5 cm diameter in 19 0.25 ha plots ranging in age from 3 to >50 yr since disturbance. We also measured plant functional traits related to establishment, performance, and competitive ability. In addition, we examined change in forest structure, composition, species diversity, and functional diversity through succession. By using rarefaction to estimate functional diversity, we compared changes in functional diversity while controlling for associated differences in stem and species density. Basal area and species density increased with stand age while stem density was highest in intermediate secondary forests. Species composition differed strongly between mature and secondary forests. As forests increased in basal area, community-weighted mean wood density and foliar carbon increased, whereas specific leaf area and proportion of stems with exudate decreased. Foliar nitrogen peaked in medium-aged forests. Functional diversity was highest in mature forests, even after accounting for differences in stem and species diversity. Our study represents one of the first attempts to document successional changes in New Guinea's lowland forest. We found robust evidence that as succession proceeds, communities occupy a greater range of functional trait space even after controlling for stem and species density. High functional diversity is important for ecological resiliency in the face of global change.Abstract in Melanesian pidgin is available in the online version of this article.

Changing gears during succession: shifting functional strategies in young tropical secondary forests

“…While small, the number of studies addressing similar questions has increased rapidly in recent years (e.g., Alvarez-Añorve et al 2012;Becknell and Powers 2014;Dent et al 2013;Lasky et al 2014;Lebrija-Trejos et al 2010;Lohbeck et al 2013;Whitfeld et al 2014). In general, results from the present and previous studies provide increasingly strong evidence for the validity of this hypothesis across different tropical regions.…”

“…Successional gradients are characterized by clear shifts in resources and environmental conditions, i.e., from high to low light availability, air temperature and soil moisture, and species composition, i.e., from shade-intolerant to shade-tolerant species Dent et al 2013;Lebrija-Trejos et al 2010;Norden et al 2009Norden et al , 2011a, which lend support to the idea that adaptations to resource availability shape successional patterns of community composition (Rees et al 2001;Tilman 1985). To date, the mechanisms driving these patterns in tropical secondary forests have been tested explicitly in regions that vary markedly in terms of climate, soil, landuse history, and landscape configuration (e.g., Becknell and Powers 2014;Dent et al 2013;Lohbeck et al 2013;Whitfeld et al 2014).…”

“…1a; Lebrija-Trejos et al 2010) and increases with time since abandonment ( Fig. 1b; Breugel et al 2007;Lohbeck et al 2013;Whitfeld et al 2014). To improve the interpretability of main effects and interactions, plot basal area was centered (Schielzeth 2010).…”

“…Comparative studies of plant adaptations to contrasting environmental conditions have further substantiated the importance of light and the ability to endure shade in distinguishing species from different successional stages Reich 1993, 1996;Reich et al 1995). Recent chronosequence studies in Mexico, Costa Rica, Panama, and New Guinea have corroborated that successional changes in environmental conditions, principally light availability, but also air and soil temperatures and soil pH, occur in parallel with changes in species and functional composition (Becknell and Powers 2014;Dent et al 2013;Lebrija-Trejos et al 2010;Lohbeck et al 2013;Whitfeld et al 2014).…”

Tree Association with Pometia and its Structure in Logging Concession of South Papua Forest

“…At that time, seedling establishment of benefited from the opening of canopy gap Pometia resulting from logging activities where irradiance could reach understory. Most of the early seedling establishment in tropical rainforests require the irradiance to grow (DuahGyamfi et al 2014;Goodale et al 2014;Whitfeld et al 2014). On the other hand, the absence of larger individuals of Pometia in logged forest indicated that the logged forests are still recovering from logging impact.…”