Habitat Heterogeneity In Habitat Diversity

Altitude is an important factor in habitat diversity since it determines changes in availability of resources, such as heat and water (Körner 2000); but it is merely a surrogate for a suite of biotic and abiotic factors that influence species richness (Rahbek 1995). The altitudinal gradient is the key factor forming different mountain habitats, and contains the variation of many direct ecological factors at large scale, such as temperature, humidity, sunlight, and soil property, influencing the distribution and structure of plant communities, as well as species biodiversity (Xu et al. 2010). Variations in plant diversity can be linked to several ecological gradients (Chawla et al. 2008), but altitudinal gradient is one of the decisive factors

Habitat heterogeneity can refer to vertical and horizontal vegetation, as well as the landscape structure in terrestrial ecosystems (Tews et al. 2004). Although the definition of heterogeneity is controversial (Li & Reynolds 1995), some authors have reported a positive effect of habitat heterogeneity on species richness (Bell et al. 2000; Bestelmeyer & Wiens 1996). It is assumed to be an important factor maintaining ecosystem biodiversity (Xu et al.

In these environments, the arthropods play important roles (mainly in and above ground) as decomposers, herbivores, granivores and predators, controlling the nutrient cycling and the energy flow through the different levels in the food chain (Crawford 1986; Polis 1991; Greenslade 1992; Ayal et al. 2007). Considering their role in natural systems, they are important model taxa for comparing communities dependent on habitat (Lassau et al. 2005), and can be used to monitor changes in the environment because of their high abundance, species richness and habitat fidelity (Andersen & Majer 2004), which, together with their diverse characteristics and ecological requirements (Wettstein & Schmid 1999) make them useful indicators of environmental