Ecological and socio-cultural potential of human modified forest landscapes in conservation of tree species diversity : the case of Vhembe biosphere reserve, South Africa

Abstract

This thesis aimed at evaluating the potential ecological and socio-cultural values of Human Modified Forest Landscapes (HMFL) in comparison to the State-protected Indigenous Forests (SIF). This was crucial in light of the increasing human domination, deforestation, and fragmentation of landscapes, and the consequent alarming rate of global biodiversity loss. At the same time, there is growing scepticism on the performance of protected areas as a standalone strategy for biodiversity conservation. However, the proponents of protected areas still pursue the expansion of its coverage to half of the earth surface, aptly known as the “Half Earth” (HE) movement. HE proponents presume that resource use-behavior is determined by ecological abundance of resources, and view local people as a threat to biodiversity. In parallel, the opponents of the HE conservation option advocate for the New Conservation Science (NCS) and denounce the scientific basis of protected areas as a denial to the remarkable resilience of nature and the exclusion or restriction of local people to their cultural landscape as unethical. NCS proponents argue that effective management of Human Modified Forest Landscapes (HMFL), that embraces culture/Traditional Socio-Ecological Knowledge (TSEK), is more important for biodiversity than protecting relatively intact forest ecosystems that exclude local people. Studies have shown that there is a higher compliance rate by traditional society to social norms that govern cultural protected forests, than to rules imposed on state indigenous forests. There is currently no consensus about whether HMFL or SIF is a better option for biodiversity conservation; hence, the need for this study. Furthermore, although there is a claim by previous studies on the positive link between the Vhavenda people’s culture and surrounding ecosystems in the Vhembe Biosphere Reserve (VBR), South Africa, there has not been a systemic evaluation of the potential of HMFLs for conservation of tree species diversity from a socio-ecological perspective. The study was conducted in two Forest Reserves (FRs) of the Eastern Soutpansberg forest landscape, which are part of VBR; namely Mafhela Reserve (MFR) and Thathe Vondo Forest Reserve (TVFR). MFR is relatively more simplified or fragmented by disturbance than the complex TVFR. First, tree-based traditional land use regimes of the two FRs were categorized into two major groups: (i) Human modified forest landscape (HMFL), under the custody of traditional authorities that comprises highly disturbed Common Resource Use Zones (CRUZ), intermediately disturbed Trees Along Streams and Rivers (TATR) and minimally disturbed Culturally Protected (sacred) Forest Areas (CPA) and (ii) State-protected Indigenous Forests (SIF). Four independent studies were conducted to address the aim of the study (Chapters 2-5). Using landscape moderation insurance and Intermediate Disturbance Hypothesis (IDH) as a framework, the study assessed the difference in the resilience of local assemblage along a land use intensity gradient. Univariate and multivariate statistical techniques, including various ordination diagrams, were used to analyse the beta (β)–diversity (Jaccard dissimilarity matric on presence/absence data) and the difference in species richness in HMFL. This study showed that land use disturbance affects mean beta (β)–diversity in an ecological contrasting manner between the simplified MFR and a complex TVFR. In MFR, while the species richness along a land use gradient response did not conform to the predication of IDH, the species composition changed along the land use gradient. In contrast, the local assemblages in TVFR showed that, while the species richness conformed to IDH, the species composition was more resilient to change. However, resilience does not mean the absence of dynamism in local assemblages. Even in the absence of human disturbance, the local neighbourhood effect together with biotic and abiotic elements, may still incur small scale changes in species composition. In order to evaluate the efficiency of the protected area for the conservation of rare species, responses of different facets of beta (β)–diversity, using the Hellinger Distance Matrix and species abundance distribution, were used. This was crucial to disentangle the conservation value of alternative options of conservation for rare species, such as canopy and sub-canopy trees of a wide geographic range and endemic species, from the overall biodiversity value. The result showed that SIFs in the two FRs differed in their efficiency of protecting rare species, in comparison with each of the land use regimes of the HMFLs. In MFR, all land use regimes lost species richness, became more uneven, and the dominance of trees declined and was replaced by shrubs along the land use gradient in comparison with SIF. In contrast, SIF in TVFR was not exceptionally efficient compared to others, except with intensively disturbed CRUZ, where the decline of the relative abundance of rare species was observed. Almost all land uses in both FRs retained some endemic trees that were either rare or absent in SIF. Using ecological assessment and ethnobotanical techniques, the study also tested the ecological appearance hypothesis of whether an ecological abundance of resources can sufficiently explain the use-behaviour of traditional society for various forest and tree species’ utilities. Both parametric and non-parametric tests were used to analyze the data gathered from 135 households. The result from the two communities (two villages from each FR) of the Vhavenda people revealed the homogeneity of cultural values pertaining to resource use-behaviour, although they reside in ecologically different forest landscape conditions. The use-value of habitats increases with the increase of the land use intensity gradient in the multifunctional landscape as defined by cultural norms and taboos, with SIF as an exception. Despite its presumed strict protection status, SIF had the same use-value as with open access CRUZ. Almost no forest resource harvesting was reported from CPA. Moreover, abundance of species did not sufficiently explain the use-value of species. The findings show that culture plays a more predominant role in explaining use-behavior than an abundance of resources. The study further compared the compliance behaviour of local communities towards rules that govern CPA and SIF. The findings showed that compliance behaviour of local people to CPA was a social norm while non-compliance to SIF appeared to be a new norm. On average, an individual holds about four out of the seven perceived local values that motivated the need to conserve forest and tree species diversity. These include the need to protect forests and trees of outstanding utility values, watershed protection, and cultural values (identity and symbolic value), protection of endangered species, and wildlife habitat, in descending order. This shows that, unlike the dichotomy of value orientations between HE and NCS proponents, local people held a continuum of biocentric and anthropocentric value orientation in managing their landscapes. Almost all of the participants in the study showed their willingness to take part in conservation. The study suggests that SIFs become more vulnerable to non-compliance when the necessity of resources for rural livelihoods arise due to misalignment of the rules to local values, social norms, and taboos; not because of ignorance. Based on the findings of the study, the potential of HMFLs for the conservation of tree species diversity over the effectiveness and efficiency of protected areas depends on the prevalent socio-ecological context. It demands context-specific policies that are informed by interdisciplinary science using complimentary theories and models rather than a mere dichotomy of conservation based on ideological options of NCS and HE. The claim by the NCS on the remarkable resilience of nature is an oversimplification of a complex and non-linear response of local assemblages to disturbance that might misinform future conservation strategies. Equally, the expansion of protected areas of the HE option, with the presumption that local people are threats to biodiversity, may be deemed to fail. Instead, inclusive policy reform that integrates local peoples’ cultural values and TSEK, either for restoration or conservation of biodiversity, depending on the existing landscape context, plays a significant role. An improved landscape complexity improves the resilience of local species diversity.