Mapping β-Diversity and Developing Biodiversity-Friendly Tea in the Eastern Himalayas

Abstract

This dissertation promotes biodiversity conservation through two related studies. The first analyzes β-diversity mapping techniques and introduces a standardized framework that combines α- and β-diversity for conservation planning, using the Eastern Himalayas as a case study. The second study involves fieldwork in the same region. It examines traditional forest tea systems from ecological and socioeconomic perspectives. The results inform the creation of criteria for biodiversity tea certification, providing a practical tool for conservation and landscape restoration. β-diversity mapping lacks a consistent methodology. Through a systematic review of published studies, this chapter breaks the mapping process into three key steps. Result maps based on the same species show that inconsistent choices at each step produce vastly different spatial patterns, making cross-study comparisons unreliable and limiting practical use in conservation. To address this, the chapter proposes a standardized mapping method that counts the edges of species ranges. Using the standardized range-edge method developed in Chapter 1, it maps species turnover at high resolution across the Eastern Himalayas. The results reveal a clear pattern: areas of high species richness and areas of high species turnover are concentrated in different locations. Each highlights a different and complementary aspect of biodiversity. This chapter emphasizes that including both metrics in conservation planning is crucial. Building on the mapping framework outlined in Chapters 1 and 2, this chapter shifts focus to ground-level analysis. It presents vegetation surveys, household interviews, and landcover mapping at 102 sites in Xishuangbanna, Yunnan. The findings show that forest tea is not a separate landcover category but a variety of vegetation states. Cultural history and ethnic land-use traditions influence vegetation structures and management practices as much as environmental factors. Economically, forest tea yields are lower but generate higher net profits. Acoustic bird monitoring and camera-trap surveys show that complex forest tea supports bird communities similar to those in native forests. However, threatened diurnal mammals are only found in native forests, regardless of the tea field structure. These findings suggest that the conservation value of forest tea varies by taxon and vegetation structure, highlighting that developing biodiversity-friendly tea and protecting native forests should be viewed as complementary conservation strategies rather than alternatives.