Edaphic macrofauna as a bioindicator in semiarid ecosystems of the Santa Elena Peninsula, Ecuador

Abstract

The effect of the intensity of land use on soil macroinvertebrate communities was investigated, as well as the sampling moment and the functionality of macrofaunistic indicators, under semi-arid conditions in the province of Santa Elena; an area in the process of desertification and located in the coastal region of Ecuador. Two sampling moments at the beginning of the rainy season and two land use systems, a Regenerated Tropical Dry Forest (BSTr) and a Short Cycle Crop (CCC) were evaluated. Macroinvertebrates were collected according to the TSBF methodology, and their richness, diversity and abundance were determined, as well as the functional indicator Detritivores/No Detritivores. The statistical analysis through the Stats package of R Core Team, mainly contemplated the non-parametric Kruskal-Wallis test. No significant differences were found between the sampling times, which made it possible to consider both samplings as one within the study period. The lower values ​​of richness, diversity and abundance of the edaphic macrofauna, as well as the substantial decrease of the entire food web in the CCC with respect to the BSTr, responded to the negative impact of intense soil management and the lack of plant cover. The result of the Detritivores/No Detritivores indicator, with close proportions between its components in both use systems and with a lower value in the BSTr, indicated an instability in the edaphic environment mainly due to the semiarid conditions in the region.