Spatial distribution of termite mounds in a Tabuleiro Forest, northern Espírito Santo

Abstract

The Termites are insects that belong to the order Isoptera and have the habit of living in colonies, which are divided into social classes (castes). These animals ate detritivorous, assuming an important role in nutrient cycling, and have great importance for several ecological processes. The distribution of its colonies in the environment may vary due to variations in the soil type, concentrations of nutrients and depth, climatic changes and deforestation. Termite colonies can have three basic patterns of spatial distribution in the environment: random, clustered or uniform. The aim of this study was to analyze the spatial distribution of termite mounds in a Tabuleiro Forest. We hypothesized that the pattern of distribution of termite mounds would be classified as uniform. This study was conducted at the Vale Nature Reserve, located in Linhares (ES). One quadrant was defined, with a total area of 2.88 ha. The found termite mounds were counted, georeferenced and classified as actives and inactives. Georeferenced termite mounds, were plotted in one graph grid, whose size of grid was based on the total sample area divided by the total number of termite mounds. The spatial distribution of termite mounds was verified by the Poisson distribution. A total of 281 termite mounds were found, with 189 active and 92 inactive. The Poisson index was 0.91 which is very close to 1 and different from 0.5, suggesting a uniform distribution and supporting the proposed hypothesis. The spatial distribution of termite mounds in a particular geographic area is influenced by physical and, mainly, biological factors. Termites survive better in wet soils (non-sandy) once they lose water very easily, given that their body surface is covered by a very thin layer of chitin. The spatial distribution of termite mounds located in Vale Nature Reserve, may probably be related to environmental variables.