Changes in ecosystem service values strongly influenced by human activities in contrasting agro-ecological environments

• Published in: Ecological processes Vol. 10; no. 1; pp. 1 - 18
• Main Authors: Berihun, Mulatu Liyew, Tsunekawa, Atsushi, Haregeweyn, Nigussie, Tsubo, Mitsuru, Fenta, Ayele Almaw
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 22-07-2021; Springer Nature B.V; SpringerOpen
• Subjects: Acacia decurrens; Agriculture; Agro-ecologies; Cultivated lands; Drought prone; Earth and Environmental Science; Ecological effects; Ecosystem management; Ecosystem services; Ecosystems; Environment; Erosion control; Evaluation; Expansion; Food production; Human influences; Introduced species; Invasive plants; Invasive species; Land cover; Land use; Land use/land cover; Natural vegetation; Plant cover; Plantations; Planting; Population growth; Provisioning; Rangelands; Strategic management; Sustainable use; Vegetation; Vegetation cover; Watersheds; Nigeria; Aba Nigeria; United States > US; Farming practices; Upper Blue Nile basin; Land use/land cover; Plantations; Drought prone; Ecosystem services; Agro-ecologies
• ISSN: 2192-1709; 2192-1709
• DOI: 10.1186/s13717-021-00325-1

Background
Evaluating the impacts of land-use/land-cover (LULC) changes on ecosystem service values (ESVs) is essential for sustainable use and management of ecosystems. In this study, we evaluated the impact of human activity driven LULC changes on ESVs over the period 1982–2016/17 in contrasting agro-ecological environments: Guder (highland), Aba Gerima (midland), and Debatie (lowland) watersheds of the Upper Blue Nile basin, Ethiopia.
Results
During the study period, the continuous expansion of cultivated land at the expense of natural vegetation (bushland, forest, and grazing land) severely reduced the total ESV by about US$ 58 thousand (35%) in Aba Gerima and US$ 31 thousand (29%) in Debatie watersheds. In contrast, the unprecedented expansion of plantations, mainly through the planting of
Acacia decurrens
, led, from 2006, to a ESV rebound by about US$ 71 thousand (54%) in Guder watershed, after it had decreased by about US$ 61 thousand (32%) between 1982 and 2006. The reduction in natural forest area was the major contributor to the loss of total ESV in the study watersheds, ranging from US$ 31 thousand (63%) in Debatie to US$ 96.9 thousand (70%) in Guder between 1982 and 2016/17. On an area-specific basis, LULC changes reduced the average ESV from US$ 560 ha
−1
year
−1
(1982) in Guder to US$ 306 ha
−1
year
−1
(2017) in Debatie watersheds. Specific ESVs such as provisioning (mainly as food production) and regulating services (mainly as erosion control and climate regulation) accounted for most of the total ESVs estimated for the study watersheds.
Conclusions
In most cases, the total and specific ESVs of the watersheds were negatively associated with the population growth, which in turn was positively associated with the expansion of cultivated land over the study period. In Guder, however, ESVs were positively associated with population growth, especially after 2012. This is mainly due to the expansion of
Acacia decurrens
plantations. Our results suggest, therefore, that future policy measures and directions should focus on improving vegetation cover through planting multipurpose trees such as
Acacia decurrens
to prevent future loss of ESV in the midland and lowland regions of the Upper Blue Nile basin and beyond. However, caution must be taken during plantation of invasive species as they may have undesirable consequences.