Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Leaf colonization by aquatic invertebrates in a tropical stream: are there differences between native species and Eucalyptus grandis (Hill ex Maiden) in the rainy and dry seasons?

Abstract

The objective of the present study was to verify if there are differences in the colonization of invertebrates between the leaves of native and exotic species in the rainy and dry seasons. Senescent leaves were collected from a riparian forest along a stream and dried in a greenhouse at 60±5°C for 48 h. After drying, the plant material was added to litter bags randomly arranged in the stream. Two experimental treatments were used: (1) Eucalyptus grandis (non-native) and Lithraea molleoides (native species); and (2) Eucalyptus grandis (non-native) and Maytenus aquifolium (native species). The results showed that colonization mainly began on the 14th day and continued until the 28th day. Greater invertebrate abundances were found on the native leaves in the dry season and on the non-native leaves in the rainy season. Regarding taxonomic richness, the highest values were found starting on day 21 and there was a difference in the rainy season between native and non-native species, which did not occur in the dry season. According to a statistical analysis, in the rainy season the abundance of invertebrates was higher for the non-native species compared to the native species. On the other hand, there was a negative effect of the rainy season on richness. For both experiments, the main effect of the days did not influence the richness. There was an interaction effect between time of year and days of observation; in the rainy season, it is expected that there will be a significant linear increase in abundance over the days.