Biodiversity In Ecosystems

Biodiversity is the life variation, including variation among genes, species and functional traits. Therefore, it includes all species of plants, animals and micro-organisms that interact in an ecosystem (Vandermeer & Perfecto 1995). Biodiversity is measured as richness, evenness and heterogeneity among different life forms (Cardinale 2012).

Biodiversity performs in many ecological functions like primary production, nutrient cycles, decomposition. In addition, biodiversity provides many ecological services. In the case of natural ecosystems, biodiversity generates and maintain the soil, maintain hydrological cycles, purifying water and air, recycle of nutrients, detoxifying pollutants, regulate climate, and controls flooding and diseases.

Although, in modern agriculture exist a extreme vulnerability associated with genetic uniformity. Polycultures, agroforestry and traditional cropping systems are genetically diverse. Genetic diversity is important due to confer partial resistance to pests and pathogens and allows to exploit different kind of soil and micro-climates for other uses (Brush, 1982). Some studies show that the yield of commercial crops is increased by intraspecific genetic. The stability of crop yield can be increased by the genetic diversity. It can facilitate rotations minimizing crop damage caused by disease and pests due to the increase of the ecosystem diversity. Also, rotation and multiple cropping systems are strategies for monocultures (Altieri, 1999). In addition, the diversity of tree species increases production of wood in plantations and the diversity of plant species in grasslands enhances the production of fodder. The resistance to invasion increase with the plant biodiversity. Moreover, the diversity of plant species increases carbon of the soil, biomass production, nutrient mineralization and soil organic matter. Therefore, impacts on biodiversity can have strong effects on ecosystem services (Cardinale, 2012).

Traditional agroforestry system, contain many trees minimizing nutrient leaching and soil erosion and restore key nutrients (Marten, 1986). Rustic agroforests have the

The stability of the insect community depends in the trophic link, in the diversity of the agroecosystems and in the time that the diversity has remain undisturbed (Southwood & Way 1970). Also, the weeds influence the abundance and the diversity of insect, supporting arthropods that can suppress pest populations. Therefore, with a mosaic structure can lead to the creation of many habitats for a beneficial arthropodes species (Altieri 1994). For instance, ant species richness and equitability are used as indicators of environmental change in disturbed landscapes, presenting lower species diversity in ecosystems disturbed by agriculture (Graham et al. 2009).

This study will be focused on different species richness across several types of cacao management systems in Indonesia. The management intensity affects the richness of the species. Therefore, this study presented seven different types of management systems which is expected to have a different effect in the three different taxa (bids, ants and trees) and in the dependency of forest. Regarding this, we expected that:

1. Specie richness is lower in ecosystems with management intensity in cacao landscapes.

2. Differences in taxonomic groups are affected different by intensity of management. Birds are more affected by management intensification than