Effects of Selective Logging on the Diversity and Abundance of Flowering and Fruiting Understory Plants in a Central Amazonian Forest

Functional Diversity Changes after Selective Thinning in a Tropical Mountain Forest in Southern Ecuador

Background: The impact of selective thinning on forest diversity has been extensively studied in temperate and boreal regions. However, in the tropics, knowledge is still poor regarding the impacts of this silvicultural treatment on functional diversity, especially in tropical mountain forests, which are considered to be highly biodiverse ecosystems and also endangered by human activities. By evaluating the changes on functional diversity by using different indicators, hypothesizing that selective thinning significantly affects (directly or indirectly) tropical mountain forests, this work promotes sustainable ecosystem use. Methods: A total of 52 permanent plots of 2500 m2 each were installed in a primary mountain forest in the San Francisco Biological Reserve to assess the impact of this silvicultural treatment. Selective thinning can be defined as a controlled process, in which trees that compete with ecologically and/or valuable timber species are progressively removed to stimulate the development of profitable ones, called potential crop trees (PCT). In doing so, the best specimens remain in the forest stand until their final harvest. After PCT selection, 30 plots were chosen for the intervention, while 22 plots served as control plots. The thinning intensity fluctuated between 4 and 56 trees ha−1 (average 18.8 ± 12.1 stems ha−1). Functional Diversity (FD) indices, including the community weighted mean (CWM), were determined based on six traits using the FD package implemented in R software. The difference between initial and final conditions of functional richness (FRic), functional divergence (FDiv), functional evenness (FEve), functional dispersion (FDis), and Rao quadratic entropy (RaoQ) was modeled using linear mixed models (LMM). As fixed factors, we used all the predictors inherent to structural and ecological forest conditions before and after the selective thinning and as a random variable, we used the membership to nested sampling units. Results: Functional Richness (FRic) showed significant changes after selective thinning, the other indexes (FEve, FDis, FDiv, RaoQ) were only influenced by predictors related to ecological conditions and characteristics of the community.

The influence of logging upon the foraging behaviour and diet of the endangered Bornean banteng

Logging causes soil compaction and alters the vegetation structure and plant diversity, and ungulates must adapt to modified conditions if they are to survive. We investigated the impact of logging upon the foraging ecology of the Bornean banteng using camera traps and botanical surveys. General linear models were used to explore the effects of site characteristics and plant diversity upon foraging duration, and plant specimens were identified to confirm dietary preferences. Foraging events were recorded over 40,168 nights in five forests. Foraging duration significantly decreased in open areas depauperate in species richness (F=7.82, p=<0.01); however, it increased with elevation (F=3.46, p=0.05). Their diet comprised eight invasive species (Mikania cordata and Chromolaena odorata, Cyperus difformis, Fimbristylis littoralis and Scleria sp., Desmodium triflorum, Eleusine indica and Selaginella sp.), which are characteristic of disturbed forest and fast to establish. Logging creates ideal conditions for these plants, which are preferentially selected by bantengs. Whilst logging may increase forage, the disturbances logging causes to the bantengs and the ensuing poaching may counteract any positive benefits. Developing forest management strategies that incorporate conservation of the bantengs may in turn encourage more favourable conditions for emergent timber species and also conserve this endangered wild cattle species.

The response of avian feeding guilds to tropical forest disturbance

Anthropogenic habitat disturbance is a major threat to tropical forests and understanding the ecological consequences of this disturbance is crucial for the conservation of biodiversity. There have been many attempts to determine the ecological traits associated with bird species' vulnerability to disturbance, but no attempt has been made to synthesize these studies to show consensus. We analyzed data from 57 published studies (covering 1214 bird species) that investigated the response of tropical bird assemblages to moderate forest disturbance (e.g., selective logging). Our results show that the mean abundance of species from six commonly reported feeding guilds responded differently to disturbance and that species' ecological traits (body size, local population size, and geographic range size) and evolutionary relationships may influence responses in some guilds. Granivore abundance increased significantly and insectivore and frugivore abundance decreased significantly following disturbance. These general conclusions were robust to the effects of ecological traits and phylogeny. Responses of carnivores, nectarivores, and omnivores were less clear, but analyses that accounted for phylogeny indicated that these guilds declined following disturbance. In contrast to the other guilds, the reported responses of carnivores and nectarivores differed among regions (Asia vs. Neotropics) and were influenced by the sampling protocols used in different studies (e.g., time since disturbance), which may explain the difficulty in detecting general responses to disturbance in these guilds. Overall, general patterns governed the responses of species to habitat disturbance, and the differential responses of guilds suggested that disturbance affects trophic organization and thus ecosystem functioning.