The impact of logging and secondary succession on the below-ground system of a cloud forest in Mexico.

Abstract

AbstractAlthough the process of secondary succession in tropical montane cloud forest (TMCF) has been studied in some detail, very little is known about the consequences of changes in vegetation composition on nutrient budgets and biodiversity below ground. In this chapter we present a conceptual model of how changes in the organic matter provided by the tree community in different stages of secondary succession might mediate the linkage between above-ground and below-ground biodiversities. This model is based on evidence from a study on the litter composition, topsoil nutrient concentration and soil macroinvertebrate fauna in two pristine and two recently logged sites, as well as three successional chronosequences (15-100-year-old forests) of TMCF in Oaxaca, Mexico. Results suggest that low intensity selective logging compromises the close interdependence between the composition, spatial structure and function of above-ground and below-ground biodiversities. The homogenization of the organic matter input to the soil that follows the colonization of pines in disturbed forests may threaten the conservation of the spatial structuring of above- and below-ground communities and possibly the conservation of their high biodiversity. In the absence of further information, conservation measures should pay particular attention to the native species of worm Ramiellona willsoni that seem not to be able to re-establish in secondary forest and to the release of P to the soil that results from continuous disturbance. The persistence of late-successional tree species in these forests may partly be associated with their ability to compete in the noticeably phosphorus-poor soils of mature forests.