Contributions of urban green spaces for climate change mitigation and biodiversity conservation in Dessie city, Northeastern Ethiopia

Abstract

Scientific studies about the role of urban green spaces (UGSs) in biodiversity conservation and climate change mitigation are limited in developing countries. Therefore, the aim of this study was to assess the role of UGSs in biodiversity conservation and climate change mitigation. Using a systematic sampling method a total of 137 sample plots of various sizes were laid per cluster. The analysis of variance (ANOVA) was undertaken among clusters using the Honestly Significant Difference (HSD) test at a 5% level of significance. A total of 127 woody species belonging to 58 families and 99 genera were recorded. Of the total species, 7 (5.51%), 34 species (26.77%), and 86 (67.72%) were endemic, exotic, and indigenous to Ethiopia, respectively. The presence of threatened or endangered trees in Ethiopia, such as Hagenia abyssinica and Juniperus procera in the UGSs of Dessie, indicates that UGSs could be another potential site for biodiversity conservation. The overall mean carbon stock (ton ha−1) and its total CO2 equivalent of UGSs of Dessie are 745.17 ± 170.86 and 2734.79 ± 627.06, respectively. This indicated a significant potential of UGSs to mitigate a changing climate. A statistically significant difference (p < 0.05) was revealed for the carbon stock and diversity. The highest mean biomass carbon was recorded in the urban forests (1448.14 ± 736.32 tons C ha−1) and the lowest in urban Homegarden (61.28 ± 0.231 ton C ha−1). Correlation analysis revealed a weak positive relationship (r = 0.26) between biomass carbon stock and Shannon's index. It is concluded that UGSs have an important role in mitigating climate change through carbon sequestration and biodiversity conservation. Therefore, urban plans should consider the roles of urban green space at every stage of planning.