Determinants of litter decomposition rates in a tropical forest: functional traits, phylogeny and ecological succession

Abstract

Plant litter decomposition is one of the most important processes in terrestrial ecosystems, as it is a key factor in nutrient cycling. Decomposition rates depend on environmental factors, but also plant traits, as these determine the character of detritus. We measured litter decomposition rate for 57 common tree species displaying a variety of functional traits within four sites in primary and four sites in secondary tropical forest in Madang Province, Papua New Guinea. The phylogenetic relationships between these trees were also estimated using molecular data. The leaves collected from different tree species were dried for two days, placed into detritus bags and exposed to ambient conditions for two months. Nitrogen, carbon and ash content were assessed as quantitative traits and used together with a phylogenetic variance– covariance matrix as predictors of decomposition rate. The analysis of the tree species composition from 96 quadrats located along a successional gradient of swidden agriculture enabled us to determine successional preferences for individual species. Nitrogen content was the only functional trait measured to be significantly positively correlated with decomposition rate. Controlling for plant phylogeny did not influence our conclusions, but including phylogeny demonstrated that the mainly early successional family Euphorbiaceae is characterized by a particularly high decomposition rate. The acquisitive traits (high nitrogen content and low wood density) correlated with rapid decomposition were characteristic for early successional species. Decomposition rate thus decreased from early successional to primary forest species. However, the decomposition of leaves from the same species was significantly faster in primary than in secondary forest stands, very probably because the high humidity of primary forest environments keeps the decomposing material wetter.

Impact of an invasive alien plant on litter decomposition along a latitudinal gradient

“…Similarly, stem traits such as low stem‐specific density (SSD) also (indirectly) relate to fast leaf litter decomposition (Szefer et al. ). The species‐level link between leaf traits and litter decomposition has also been shown to translate to the community level, with community‐weighted mean (CWM) traits relating to decomposition rates of the community litter (Garnier et al.…”

“…In an increasingly globalized world, the number of alien plant species invading plant communities continues to rise (van Kleunen et al 2015). One major concern is that invasive alien species will lead to significant changes in functioning of the invaded ecosystem (e.g., Dassonville et al 2008, Py sek et al 2012.…”

“…More specifically, leaf traits associated with fast growth and resource acquisition, such as high leaf nutrient concentrations, high specific leaf area (SLA), low leaf dry matter content (LDMC) as well as leaf toughness and thickness, have been shown to directly relate to faster leaf litter decomposition rates (Allison and Vitousek 2004, Wright et al 2004, Kazakou et al 2006, Orwin et al 2010. Similarly, stem traits such as low stemspecific density (SSD) also (indirectly) relate to fast leaf litter decomposition (Szefer et al 2017). The species-level link between leaf traits and litter decomposition has also been shown to translate to the community level, with community-weighted mean (CWM) traits relating to decomposition rates of the community litter (Garnier et al 2004, Quested et al 2007, Finerty et al 2016, Garc ıa-Palacios et al 2017.…”

Recovery of decomposition rates and decomposer invertebrates during rain forest restoration on disused pasture

“…Decomposition rates have been shown by several previous studies to be greatly reduced when tropical forests are converted to anthropogenic pasture or agricultural use (Lorenzo et al., ; Paudel et al., ; Szefer et al., ). Our study similarly revealed reduced decomposition rates in anthropogenic pasture compared to forest.…”

“…(); (3) Szefer et al. (); (4) Paudel et al. (); (5) Barlow, Gardner, Ferreira & Peres, (); (6) Xuluc‐Tolosa, Vester, Ramırez‐Marcial, Castellanos‐Albores & Lawrence (); (7) Ewel (); (8) Mendoza, Gallardo, Turrion, Pando & Acenolaza (); (9) Ostertag, Marin‐Spiotta, Silver & Schulten (); (10) Vasconcelos & Laurance (); (11) Barajas‐Guzmán & Alvarez‐Sánchez (); (12) Gove et al.…”