Vegetation Composition and Ecological Benefits of Home Gardens in the Meegahakiula Region of Sri Lanka

Abstract

Clearing of natural ecosystems and land degradation due to unsustainable agricultural practices are becoming threats to the sustainability and productivity of agricultural systems in Sri Lanka. Tropical home gardens can be identified as an alternative, which provide economic and socio-cultural benefits to the subsistence farmers. These home gardens generate income as well as serve as a source of nutrition to the households. Along with the economic value, home gardens are known for their high species diversity. The broad objective of this study was to quantify the species diversity of perennials and annuals by determining the species composition of 30 home gardens in the Meegahakiula region of Sri Lanka. These 30 home gardens were selected randomly from three slope categories according to topographical arrangement as steep (> 30% slope), moderate (10 – 30% slope) and flat land (< 10% slope). The Shannon Weiner and Margalef indices were calculated in order to ascertain the levels of diversity of perennial and annual species in these home gardens. The relative importance value was calculated separately for perennial species and annual species. The Shannon Weiner index of perennial species was similar to that of the natural forest in Kerala, India and home gardens in Indonesia. Five major perennial species categories and six important annual species were identified in home gardens. There was a greater distribution of annuals in home gardens in the flat land category while the home gardens with moderate and steep land category had a distribution of perennial species. INTRODUCTION