Quantifying habitat impacts of natural gas infrastructure to facilitate biodiversity offsetting

Abstract

Habitat degradation through anthropogenic development is a key driver of biodiversity loss. One way to compensate losses is “biodiversity offsetting” (wherein biodiversity impacted is “replaced” through restoration elsewhere). A challenge in implementing offsets, which has received scant attention in the literature, is the accurate determination of residual biodiversity losses. We explore this challenge for offsetting gas extraction in the Ustyurt Plateau, Uzbekistan. Our goal was to determine the landscape extent of habitat impacts, particularly how the footprint of “linear” infrastructure (i.e. roads, pipelines), often disregarded in compensation calculations, compares with “hub” infrastructure (i.e. extraction facilities). We measured vegetation cover and plant species richness using the line-intercept method, along transects running from infrastructure/control sites outward for 500 m, accounting for wind direction to identify dust deposition impacts. Findings from 24 transects were extrapolated to the broader plateau by mapping total landscape infrastructure network using GPS data and satellite imagery. Vegetation cover and species richness were significantly lower at development sites than controls. These differences disappeared within 25 m of the edge of the area physically occupied by infrastructure. The current habitat footprint of gas infrastructure is 220 ± 19 km2 across the Ustyurt (total ∼ 100,000 km2), 37 ± 6% of which is linear infrastructure. Vegetation impacts diminish rapidly with increasing distance from infrastructure, and localized dust deposition does not conspicuously extend the disturbance footprint. Habitat losses from gas extraction infrastructure cover 0.2% of the study area, but this reflects directly eliminated vegetation only. Impacts upon fauna pose a more difficult determination, as these require accounting for behavioral and demographic responses to disturbance by elusive mammals, including threatened species. This study demonstrates that impacts of linear infrastructure in regions such as the Ustyurt should be accounted for not just with respect to development sites but also associated transportation and delivery routes.

FORUM: Perverse incentives risk undermining biodiversity offset policies

“…Developers overselling their offset gains may reinforce this false confidence in offsets (Jones et al . ).…”

Integrating spatially realistic infrastructure impacts into conservation planning to inform strategic environmental assessment

“…Several technical challenges and assumptions need to be dealt with so that SCP outputs are useful for SEA. For reasons of simplicity rather than technical constraints, conservation prioritizations typically assume that threats only have direct impacts (Eigenbrod, Hecnar, & Fahrig, 2009;Jones, Bull, Milner-Gulland, Esipov, & Suttle, 2014), that impacts do not vary across taxa (e.g., Kujala, Whitehead, Morris, & Wintle, 2015;Laurance et al, 2014), and that biodiversity no longer persists in impacted sites (e.g., Bunton et al 2015;Grantham et al, 2008). Historically, diffuse impacts were also poorly dealt with in EIA (Drayson, Wood, & Thompson, 2017).…”

Quantifying the conservation gains from shared access to linear infrastructure

“…Recognition of the cumulative impacts of linear infrastructure (Raiter et al 2014) means researchers are now beginning to explore the environmental impacts of large transportation networks, which can be substantial (e.g., Jones et al 2014). For example, the impacts of roads and rail linking mines to markets can be as large as or larger than the direct impacts from the associated mines (Majer 2014).…”