Influences of shale gas well-pad development on land use and vegetation biomass in a shale gas mining area.

It is not clear how shale gas mining would affect land use change and vegetation biomass in the villages and farmlands where was substantially influenced by human activities around the well-pads of the shale gas mining areas in Sichuan Province. Using remote sensing and image interpretation in 2012 and 2017 and in situ vegetation investigation data in 2017, we analyzed the changes of land use and biomass in well-drilling fields and buffer zones and further examined the extent affected by well-drilling and subsequently vegetation biomass loss. The results showed that shale gas mining had converted 93.81 hm2 of land to mining land from 2012 to 2017, among which almost half (48.6%) was dry land (about 45.61 hm2), 17.2% forest land (16.13 hm2), 11.0% residential land (10.28 hm2), and 11.1% shrubland (10.39 hm2). The extent affected by well-drilling ranged from 0 to 50 m at the early stage, which decreased at the stage of stable gas production. As a result of well-drilling, over 2477.53 t of vegetation biomass was lost, of which 71.6% being accounted for by the well-drilling fields and the remaining (28.4%) being caused by road construction and temporary land use. Direct occupation of dry land and forested land by shale gas well-pads mainly caused land use changes and biomass losses in this shale gas mining area. Our results have implications for ecological environment management and shale gas sustainable mining in this area.