Alpine habitat dynamics and avian biodiversity in different land-use regimes on the eastern Tibetan Plateau

Abstract: Biodiversity–environment relationships are of core interest to both ecologists and conservationists. Ecological models have predicted local biodiversity patterns in relation to distributions of key environmental variables in space and time. Anthropogenic activities further complicate the biodiversity–environment relationships. Human disturbances can impact directly on the coexistence of species by intervening in the processes of competitive exclusion. Human land-uses modulate the habitat dynamics of natural systems and influence the biodiversity patterns therein, which is often accompanied by a legacy effect. Different conservation principles have arisen based on positive or negative perceptions of the human impacts on biodiversity. For instance, the wilderness approach advocates keeping nature pristine and undisturbed by humans. Contrarily, the cultural landscape approach puts current ecosystem structure into the context of evolution and human history, thus suggests that human-created habitats are crucial in maintaining the locally adapted species assemblage.
The goal of this dissertation was to understand the human–habitat–biodiversity interconnections through conducting an interdisciplinary study in the alpine grassland landscape of the eastern Qinghai-Tibetan Plateau, which is one center of bird endemism of Asia. The research also aimed to make science-based conservation recommendations for the protection of the Tibetan avifauna.
To disentangle human impacts on the vegetation changes of alpine pastures in eastern Tibet, I integrated oral history study, participatory GIS and remote sensing analysis of Landsat and MODIS time-series in order to detect the turning points of land-use and land-cover changes. Results showed that privatizations of livestock and pastures since 1984 triggered the recent grassland degradation. South-facing, mild-slope winter pastures located in higher altitudes were most susceptible to the degradation. With a time-lag of thirty years, the degradation turning point was detected in the year 2006. However, the non-synchronized land-use and land-cover changes confused local people’s perceptions of the causality. This finding bears implications for conservation management, which puts increasing weight on the traditional ecological knowledge (chapter 5).
To examine the species–environment relationship of the eastern Tibetan bird assemblage, I first developed a comprehensive set of habitat predictors employing advanced remote sensing technology, i.e. the unmanned aerial vehicles (UAVs). The UAV images provided fine scale (10-cm level) continuous data on land-cover, topographic and habitat heterogeneity features up to 200 m radius. Therefore, it was feasible to compare the explanatory powers of habitat predictors at four sample radii, i.e. 50 m, 100 m, 150 m and 200 m. The results showed that the spatial scale of 150 m radius leads to the highest explanation of variance (39.15%, p < 0.0001). 2D and 3D habitat predictors derived from the UAV data both have strong performances in explaining the variations of species compositions in the alpine bird community (chapter 6).
Using the UAV-derived habitat predictors, I further detected the patterns of local avian diversity distributions along different environmental gradients in the alpine grassland. By doing so, I tried to find the unimodal diversity pattern predicted by the intermediate disturbance hypothesis and the intermediate production hypothesis, as well as the linear pattern predicted by the habitat heterogeneity hypothesis. Meanwhile, species-level preferences and avoidances of habitat features were identified by performing generalized linear mix-effects models. The results showed that the widely tested ecological hypotheses are complementary in explaining the local diversity distributions. Particularly, the vertical complexity is the common feature required by the majority of the high-richness avian communities. However, a conservation focus on local diversity hotspots may obscure the requirement of habitat specialists, e.g. the white-rumped snowfinch, which is endemic to the Tibetan Plateau (chapter 7).
Finally, synthesizing the human–habitat–biodiversity relationships of the study area, I compared the avian diversity and endemism distributions in different habitat types and linked the habitat types to diverse pastoral land uses. I found that at the landscape scale, the key for conserving both the diversity and endemism is to maintain a high variety of habitat types. I argued that traditional pastoral land uses play a fundamental role in creating this landscape heterogeneity. Particularly, degraded pastures provide the unique habitat for endemic birds such as the white-rumped snowfinch and the ground tit. Meanwhile, I examined the possible impacts on bird habitats of the large-scale ecological restoration program taking place on the eastern Qinghai-Tibetan plateau. This on-going restoration adopts the wilderness approach aiming to increase shrubland and reverse the pasture degradation by minimizing anthropogenic disturbances. I concluded that the wilderness restoration policy is not likely to benefit the bird conservation in the highland region. Instead, it is advisable to integrate a cultural landscape perspective into the conservation of the eastern Tibetan bird assemblage (chapter 8).
This dissertation unveils the multiple dimensions of the human–biodiversity–environment relationships in the under-studied natural system of the Qinghai-Tibetan Plateau. It indicates that widely-tested ecological hypotheses complementarily explained the biodiversity patterns, and the overall diversity pattern is rather a synthesized phenomenon molded by multiple ecological processes. Advanced remote sensing technologies largely facilitate the scientific probing of this study, which illustrates the innovations in research tools can substantially change the way classic ecological questions being answered. For conservation managers, I suggest that the protection of overall biodiversity, endemic species, certain habitat types or the keystone habitat structure can respectively result in distinct community species compositions of the Tibetan avifauna. Overall, the study demonstrates that integrating a holistic or pluralist approach can lead to a comprehensive understanding of coupled human and natural system

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Dissertation, 2017

Klassifikation und Themen

• Klassifikation: Natürliche Ressourcen, Energie und Umwelt

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2018
• Urheber: Li, Li
• Beteiligte Personen und Organisationen: Storch, Ilse ; Bürgi, Matthias ; Albert-Ludwigs-Universität Freiburg. Fakultät für Umwelt und Natürliche Ressourcen

Weitere Informationen

• DOI: 10.6094/UNIFR/15820
• URN: urn:nbn:de:bsz:25-freidok-158209
• Rechteinformation: Kein Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 25.03.2025, 13:51 MEZ