Simulating anthropogenic impacts to bird communities in tropical rain forests

Abstract

We used an aggregated modelling approach to simulate the impacts of anthropogenic disturbances on the long-term dynamics of faunal diversity in tropical rain forests. We restricted our study to bird communities even though the approach is more general. We developed a model called BioDiv which simulated the establishment of hypothetical bird species in a forest. Our model was based on the results of a simple matrix model which calculated the spatio-temporal dynamics of a tropical rain forest in Malaysia. We analysed the establishment of bird species in a secondary forest succession and the impacts of 60 different logging scenarios on the diversity of the bird community. Of the three logging parameters (cycle length, method, intensity), logging intensity had the most servere impact on the bird community. In the worst case the number of bird species was reduced to 23% of the species richness found in a primary forest.

Effects of mahogany (Swietenia macrophylla) logging on small mammal communities, habitat structure, and seed predation in the southeastern Amazon Basin

“…However, even low levels of timber extraction can result in damage to 40-70% of the canopy due to the construction of roads and skid trails (Johns et al, 1996;Webb, 1997). In modelling the gap environment under additive edge effects, Malcolm (1998) found disproportionate changes in gap environments even at low harvest levels, a result echoed in Kohler et al (2002), who hypothesized strong changes in bird communities even at low harvest intensities. Based on cumulative edge effects, Struhsaker (1997) concluded that the threshold level of canopy damage might be as little as 5%.…”

Assessing Sampling Biases in Logging Impact Studies in Tropical Forests

“…However, 32% of all studies were conducted >20 years after logging disturbance. The only study representing a much longer time period (> 50 years) used a theoretical rather than empirical modelling approach [38]. …”

Multicriteria evaluation of simulated logging scenarios in a tropical rain forest

“…Therefore, we cannot exclude that even small changes in the abundance of a particular species may have large impacts on the forest ecosystem as a whole, e.g. due to bird species feeding on a certain species (Köhler et al, 2002). Now we calculate for each scenario S i a score V SC1 ðS i Þ which is the average of the scaled values v 3 ðS i Þ; v 4 ðS i Þ; and v 5 ðS i Þ: This score measures the performances of the scenario S i in criterion SC1 (note that by using the average in the aggregation of indicators I 3 -I 5 we assume that each of these indicators has equal weight).…”