Modelling future range shift gaps in a biodiversity hotspot : a case study of critically endangered plants in Madagascar

Yesuf, Gabriel Unugabo (2018) Modelling future range shift gaps in a biodiversity hotspot : a case study of critically endangered plants in Madagascar. (PhD thesis), Kingston University, .

Abstract

The synergy between climate and land use land cover change is expected to influence species distribution at local and regional scales in tropical regions. However, robust quantification of species responses and species-specific dispersal rates is lacking for most of Sub-Saharan Africa. This project aims to model range-shift gaps for 84 endangered or critically endangered plant species due to environmental change in Madagascar. To achieve this deforestation and forest degradation rates were quantified from Landsat imagery using sub-pixel analysis in two intervals (i.e, 1994-2002 and 2002-2014). Next, intensity analysis was used to determine processes of LULCC at eco-regional scale, while morphological spatial pattern analysis was applied for the determination of protected areas connectivity. Furthermore, species distribution models were constructed using hierarchical Bayesian modelling approach that included corridor connectivity and uncertainties in the derived predictions of species distribution under current and future scenarios. Finally, six spatial indices that quantified vulnerabilities, species range-shifts and displacement were derived from these predictions. The results showed differentiation in rates of deforestation and forest degradation across eco-regions. On average plant species' range were predicted to shift by approximately 300 km under future scenarios with and without connectivity. Corridor connectivity will facilitate more species upward displacements under low emission scenarios compared to high emission scenarios. Eastern humid forest were identified as 'range shift hotspots' and will be characterised by substantial species' range contractions in future scenarios. Biodiveristy in the region will experience novel threats from climate and land use cover change. Conservationist need to adapt on-going intervention programmes to prepare for the potential risks of species extinctions due to environmental change through the integration of spatial conservation planning concepts in policy formulation.

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