Les formigues com a indicador biològic de la qualitat dels prats del Parc Natural de la Zona Volcànica de la Garrotxa

Abstract

Semi-natural grasslands are habitats that have not been sown by the hand of man, they show an important species richness, they have a great ecological and productive importance and, in addition, they show notable environmental functions. Only 2% of the Parc Natural de la Zona Volcànica de la Garrotxa (PNZVG) is constituted by semi-natural grasslands, moreover, they can quickly evolve depending on environmental changes and/or management, therefore, it is highly recommended to keep the information about its conservation state updated. One of the most used groups of invertebrates as a biologic indicator and that comply all the features to be a good bioindicator is the group of ants, because they are very important at an ecologic level, they carry out many functions inside the ecosystem, ants’ diversity in the world is high, they are found in abundance in most terrestrial ecosystems, they are relatively sedentary, they are sensitive to environmental change and are easily sampled, classified and identified. Thus, in order to study the conservation state of grasslands in more detail, our aim here is to verify if the ant community is a good biological indicator to determine the semi-natural grasslands’ floristic quality of the PNZVG and, at the same time, to study the ant community at functional group levels. The results show that up to 28 species have been identified in the semi-natural grasslands of the PNZVG. The results obtained on ants diversity and the other community variables in regards to the floristic quality of the semi-natural grasslands are not significant, although we could intuit a tendency to have more ant richness and diversity in higher semi-natural grasslands floristic quality. In functional group terms, in the semi-natural grasslands of the PNZVG there are 46% of disturbance bio indicator species, 43% of maturity bio indicator species and 11% of cryptic species, meaning that the disturbance and maturity indicators are even because they are managed by grazing or haymaking and, therefore, they are under the influence of a certain disturbance. The use of the ant community as a bio indicator of the semi-natural grasslands’ floristic quality of the PNZVG should confirm or refute over time when we make use of the methodology in a monitoring program for 1-3 years