Regulatory Ecosystem Services of Forest Sacred Groves in comparison to Invasive vegetation in the urban and urban peripheries of a semi-arid region

Abstract

Amidst anthropogenic pressures, certain forest relics in the urban and rural landscapes have been traditionally protected for centuries as sacred forest groves in the Asian regions, despite lying outside the protected area network. In the current context of climate change and ensuing disasters, these forest groves and similar kind of vegetative landscapes within urban and rural could potentially increase the resilience and buffering capacity of the surrounding environs, besides providing ecosystem services. This study attempted to evaluate 50 Sacred Groves Stands (SGS) and 50 Prosopis juliflora Stands (PJS) comprehensively for the floral diversity, carbon stock and dynamics, carbon-fixing traits, dendrochronology of trees, soil nutrient profiles, and soil erosion - deemed to be regulating ecosystem services. Structural Equation Model (SEM) was applied to derive the photosynthetic efficiency of eight dominant trees species using vital input parameters including eco-physiological, morphological, and biochemical characterization. Revised Universal Soil Loss Equation (RUSLE) model in conjunction with ArcGIS Pro and ArcGIS 10.3 was adopted to map soil loss. Among the 8 selected tree species, Wrightia tinctoria (SEM Estimated Coefficient: 1.28) > Prosopis juliflora (1.22) > Acacia nilotica (1.21) > Albizia lebbeck (0.97) > Azadirachta indica (0.74) showed comparatively high carbon sequestering efficacy. SEM revealed species specific carbon sequestering functional traits (stomatal density, nitrogen fixing ability, RuBisCO and chlorophyll content) are evidently attributed to high carbon sequestration potential. Carbon source/sink determinations inferred through Net Ecosystem Productivity (NEP) assessments showed that mature SGS (0.06 ± 0.01 g C/m2/day) potentially acted as carbon sink, while matured PJS (-0.34 ± 0.12 g C/m2/day) as source. Soil erosion rates were significantly greater (29.5 ± 13.4 ton/ha/year) in SGS compared to PJS (7.52 ± 2.55 ton/ha/year).