Leaf litter arthropod responses to tropical forest restoration

Abstract

Soil and litter arthropods represent a large proportion of tropical biodiversity and perform important ecosystem functions, but little is known about the efficacy of different tropical forest restoration strategies in facilitating their recovery in degraded habitats. We sampled arthropods in four 7‐ to 8‐year‐old restoration treatments and in nearby reference forests. Sampling was conducted during the wet and dry seasons using extractions from litter and pitfall samples. Restoration treatments were replicated in 50 × 50‐m plots in four former pasture sites in southern Costa Rica: plantation – trees planted throughout the plot; applied nucleation/islands – trees planted in patches of different sizes; and natural regeneration – no tree planting. Arthropod abundance, measures of richness and diversity, and a number of functional groups were greater in the island treatment than in natural regeneration or plantation treatments and, in many cases, were similar to reference forest. Litter and pitfall morphospecies and functional group composition in all three restoration treatments were significantly different than reference sites, but island and plantation treatments showed more recovery than natural regeneration. Abundance and functional group diversity showed a much greater degree of recovery than community composition. Synthesis and applications: The less resource‐intensive restoration strategy of planting tree islands was more effective than tree plantations in restoring arthropod abundance, richness, and functional diversity. None of the restoration strategies, however, resulted in similar community composition as reference forest after 8 years of recovery, highlighting the slow rate of recovery of arthropod communities after disturbance, and underscoring the importance of conservation of remnant forests in fragmented landscapes.

Litterfall and nutrient dynamics shift in tropical forest restoration sites after a decade of recovery

“…The combined shift in the dominance of planted species (i.e., decline of N-fixing species and increase in V. guatemalensis) and the increased recruitment of unplanted species means that a decade after treatment establishment islands has similar inputs of most nutrients as the plantation and reference forest. These results in turn support the idea that applied nucleation is a viable alternative restoration strategy to plantationstyle planting that accelerates recovery of litterfall nutrient cycling and may promote a more diverse composition of litter over the long term, which could in turn affect the composition and diversity of soil invertebrates in our plots (Cole et al 2016). Both the island and plantations treatments successfully restored most litterfall nutrient inputs level after a decade, but applied nucleation does so at a lower cost than a traditional plantation, as the cost of purchasing, planting, and clearing tree seedlings is scaled to the number of tree seedlings planted.…”

Tree functional diversity affects litter decomposition and arthropod community composition in a tropical forest

“…However, interactions between arthropods and litter can be highly species‐specific (Hättenschwiler & Gasser ) and changes in tree species composition or diversity are likely to be accompanied by changes in forest floor arthropod communities (Cole et al . ).…”

“…The mineralization of organic matter is enhanced by arthropod species richness (Nielsen et al 2011, Ashford et al 2013, and previous work demonstrates that litter arthropod diversity is related to the concentrations of specific nutrients (Sayer et al 2010, Ashford et al 2013. However, interactions between arthropods and litter can be highly species-specific (H€ attenschwiler & Gasser 2005) and changes in tree species composition or diversity are likely to be accompanied by changes in forest floor arthropod communities (Cole et al 2016).…”

Invertebrate DNA metabarcoding reveals changes in communities across mine site restoration chronosequences

“…Current monitoring for invertebrates uses morphospecies and taxonomic minimalism to address constraints associated with morphology‐based identification, such as time and expertise required (Beattle & Oliver ; Pik et al ; Cole et al ). However, morphospecies may not be the most ideal solution especially in cases where organisms have polymorphic life stages or variable phenotypes (e.g.…”