Projected Landscape Impacts from Oil and Gas Development Scenarios in the Permian Basin, USA.

Projecting landscape impacts from energy development is essential to land management decisions. We forecast landscape alteration resulting from oil and gas well-pad construction across the economically important Permian Basin of Texas and New Mexico, USA, by projecting current landscape trends through 2050. We modeled three landscape-impact scenarios (low, medium, and high) using recent (2008-2017) trends in well-pad construction and energy production. The results of low-, medium-, and high-impact scenarios suggest that ~60,000, ~180,000, and ~430,000 new well pads could be constructed, potentially causing ~1000, ~2800, and ~6700 km2 of new direct landscape alteration. Almost two-thirds of all new well pads will be constructed within the geologic boundaries of the Delaware and Midland Basins. This translates into a 40, 120, and 300% increase in direct landscape alteration compared with direct alteration from existing well pads. We found that indirect effects (from edges) could increase by twofold, and that the ratio between indirect and direct alteration could decline by half as alteration intensifies and overlaps with existing alteration. The Chihuahuan Desert occupies the largest portion of the study area, and is projected to experience the largest area of alteration from future well-pad construction in the Permian Basin; the degree of direct alteration could increase by 70, 200, and 500% in this desert region, under low-, medium-, and high-impact scenarios. These scenarios can be used to design proactive conservation strategies to reduce landscape impacts from future oil and gas development.

Phylogenetic structure of Holbrookia lacerata (Cope 1880) (Squamata: Phrynosomatidae): one species or two?

Species delimitation attempts to match species-level taxonomy with actual evolutionary lineages. Such taxonomic conclusions are typically, but not always, based on patterns of congruence across multiple data sources and methods of analyses. Here, we use this pluralistic approach to species delimitation to help resolve uncertainty in species boundaries of phrynosomatid sand lizards of the genus Holbrookia. Specifically, the Spot-tailed Earless Lizard (H. lacerata) was historically divided into a northern (H. l. lacerata) and southern (H. l. subcaudalis) subspecies based on differences in morphology and allopatry, but no research has been conducted evaluating genetic differences between these taxa. In this study, patterns in sequence data derived from two genes, one nuclear and one mitochondrial, for 66 individuals sampled across 18 counties in Texas revealed three strongly supported, reciprocally monophyletic lineages, each comprised of individuals from a single geographic region. Distinct genetic variation evident across two of these regions corresponds with differences in morphology, differences in environmental niche, and lines up with the presumed geographic barrier, the Balcones Escarpment, which is the historical subspecies boundary. The combined evidence from genetics, morphology and environmental niche is sufficient to consider these subspecies as distinct species with the lizards north of the Balcones Escarpment retaining the name Holbrookia lacerata, and those south of the Balcones Escarpment being designated as Holbrookia subcaudalis.

An Improved Approach for Forecasting Ecological Impacts from Future Drilling in Unconventional Shale Oil and Gas Plays.

Directional well drilling and hydraulic fracturing has enabled energy production from previously inaccessible resources, but caused vegetation conversion and landscape fragmentation, often in relatively undisturbed habitats. We improve forecasts of future ecological impacts from unconventional oil and gas play developments using a new, more spatially-explicit approach. We applied an energy production outlook model, which used geologic and economic data from thousands of wells and three oil price scenarios, to map future drilling patterns and evaluate the spatial distribution of vegetation conversion and habitat impacts. We forecast where future well pad construction may be most intense, illustrating with an example from the Eagle Ford Shale Play of Texas. We also illustrate the ecological utility of this approach using the Spot-tailed Earless Lizard (Holbrookia lacerata) as the focal species, which historically occupied much of the Eagle Ford and awaits a federal decision for possible Endangered Species Act protection. We found that ~17,000-45,500 wells would be drilled 2017‒2045 resulting in vegetation conversion of ~26,485-70,623 ha (0.73-1.96% of pre-development vegetation), depending on price scenario ($40-$80/barrel). Grasslands and row crop habitats were most affected (2.30 and 2.82% areal vegetation reduction). Our approach improves forecasts of where and to what extent future energy development in unconventional plays may change land-use and ecosystem services, enabling natural resource managers to anticipate and direct on-the-ground conservation actions to places where they will most effectively mitigate ecological impacts of well pads and associated infrastructure.

Comparison of Recent Oil and Gas, Wind Energy, and Other Anthropogenic Landscape Alteration Factors in Texas Through 2014.

Recent research assessed how hydrocarbon and wind energy expansion has altered the North American landscape. Less understood, however, is how this energy development compares to other anthropogenic land use changes. Texas leads U.S. hydrocarbon production and wind power generation and has a rapidly expanding population. Thus, for ~47% of Texas (~324,000 km2), we mapped the 2014 footprint of energy activities (~665,000 oil and gas wells, ~5700 wind turbines, ~237,000 km oil and gas pipelines, and ~2000 km electrical transmission lines). We compared the footprint of energy development to non-energy-related activities (agriculture, roads, urbanization) and found direct landscape alteration from all factors affects ~23% of the study area (~76,000 km2), led by agriculture (~16%; ~52,882 km2). Oil and gas activities altered <1% of the study area (2081 km2), with 838 km2 from pipelines and 1242 km2 from well pad construction-and that the median Eagle Ford well pad is 7.7 times larger than that in the Permian Basin (16,200 vs. 2100 m2). Wind energy occupied <0.01% (~24 km2), with ~14 km2 from turbine pads and ~10 km2 from power transmission lines. We found that edge effects of widely-distributed energy infrastructure caused more indirect landscape alteration than larger, more concentrated urbanization and agriculture. This study presents a novel technique to quantify and compare anthropogenic activities causing both direct and indirect landscape alteration. We illustrate this landscape-mapping framework in Texas for the Spot-tailed Earless Lizard (Holbrookia lacerata); however, the approach can be applied to a range of species in developing regions globally.

Time Series Analysis of Energy Production and Associated Landscape Fragmentation in the Eagle Ford Shale Play.

Spatio-temporal trends in infrastructure footprints, energy production, and landscape alteration were assessed for the Eagle Ford Shale of Texas. The period of analysis was over four 2-year periods (2006-2014). Analyses used high-resolution imagery, as well as pipeline data to map EF infrastructure. Landscape conditions from 2006 were used as baseline. Results indicate that infrastructure footprints varied from 94.5 km2 in 2008 to 225.0 km2 in 2014. By 2014, decreased land-use intensities (ratio of land alteration to energy production) were noted play-wide. Core-area alteration by period was highest (3331.6 km2) in 2008 at the onset of play development, and increased from 582.3 to 3913.9 km2 by 2014, though substantial revegetation of localized core areas was observed throughout the study (i.e., alteration improved in some areas and worsened in others). Land-use intensity in the eastern portion of the play was consistently lower than that in the western portion, while core alteration remained relatively constant east to west. Land alteration from pipeline construction was ~65 km2 for all time periods, except in 2010 when alteration was recorded at 47 km2. Percent of total alteration from well-pad construction increased from 27.3% in 2008 to 71.5% in 2014. The average number of wells per pad across all 27 counties increased from 1.15 to 1.7. This study presents a framework for mapping landscape alteration from oil and gas infrastructure development. However, the framework could be applied to other energy development programs, such as wind or solar fields, or any other regional infrastructure development program. Landscape alteration caused by hydrocarbon pipeline installation in Val Verde County, Texas.

Impacts from above-ground activities in the eagle ford shale play on landscapes and hydrologic flows, La Salle County, Texas.

We assess the spatial and geomorphic fragmentation from the recent Eagle Ford Shale play in La Salle County, Texas, USA. Wells and pipelines were overlaid onto base maps of land cover, soil properties, vegetation assemblages, and hydrologic units. Changes to continuity of different ecoregions and supporting landscapes were assessed using the Landscape Fragmentation Tool (a third-party ArcGIS extension) as quantified by land area and continuity of core landscape areas (i.e., those degraded by "edge effects"). Results show decreases in core areas (8.7%; ~33,290 ha) and increases in landscape patches (0.2%; ~640 ha), edges (1.8%; ~6940 ha), and perforated areas (4.2%; ~16230 ha). Pipeline construction dominates landscape disturbance, followed by drilling and injection pads (85, 15, and 0.03% of disturbed area, respectively). An increased potential for soil loss is indicated, with 51% (~5790 ha) of all disturbance regimes occurring on soils with low water-transmission rates (depth to impermeable layer less than 50 cm) and a high surface runoff potential (hydrologic soil group D). Additionally, 88% (~10,020 ha) of all disturbances occurred on soils with a wind erodibility index of approximately 19 kt/km(2)/year (0.19 kt/ha/year) or higher, resulting in an estimated potential of 2 million tons of soil loss per year. Results demonstrate that infrastructure placement is occurring on soils susceptible to erosion while reducing and splitting core areas potentially vital to ecosystem services.