Vegetation cover dynamics in Chome and Kindoroko Nature Forest Reserves: Implications for the distribution and population dynamics of endangered Rhampholeon viridis

Abstract Background: The Chome Nature Forest Reserve (CNFR) and the Kindoroko Nature Forest Reserve (KNFR) in the Pare Mountains of northern Tanzania are home to the micro-endemic green pygmy chameleon ( Rhampholeon viridis ), a forest-dependent species highly sensitive to microclimatic changes. Methods: This study assessed vegetation cover change between the two forest reserves from 2000 to 2025 and evaluated the current distribution and population dynamics of R. viridis . Forest cover dynamics (FCD) were quantified using Landsat 5 and 8 satellite imagery selected for their long temporal archive and 30 m spatial resolution suitable for detecting decadal-scale forest cover change together with Normalized Difference Vegetation Index (NDVI) analysis to discriminate forested from non-forested land cover. Field surveys using stratified transects and visual encounter methods assessed chameleon abundance, age structure, sex ratio, canopy condition, and the effects of elevation on populations. Results: Results showed severe forest loss in both reserves between 2000 and 2025. In CNFR, forest area (FA) declined from 96.15 to 28.79%, while non-forest area (NFA) expanded from 3.85 to 71.20%. Similarly, in KNFR, FA decreased from 98.64 to 26.77%, with NFA increasing from 1.35 to 73.22%. A total of 603 R. viridis individuals were recorded (358 adults and 245 juveniles). However, no significant differences in abundance were observed between reserves for either juveniles (p = 0.664) or adults (p = 1.000). The population was female-biased (198 males, 405 females), with no significant sex differences (p > 0.05). No significant effect of elevation on abundance was observed (p > 0.05); however, humidity differed significantly among zones (p = 0.001). Conclusion: These findings indicate that R. viridis populations currently persist despite substantial habitat degradation, but continued forest loss may threaten long-term population stability. The study highlights the urgent need for strengthened forest protection, habitat restoration, and long-term ecological monitoring to ensure the conservation of this micro-endemic species in the Eastern Arc Mountains.