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Treatment study plot layout showing plot boundaries, two seismic lines, territories of one species, and some measurements used in analyses, all to scale. The plot is 350 m × 350 m. The vertical striped line (L) is the linear seismic line referred to in the text, while the horizontal one is the avoidance line (A). The seismic lines are subdivided into black and white segments that were used to quantify the degree of overlap of territories and seismic lines. If only edges of the territories overlapped the seismic lines, fewer “hits” of the black segments occurred. The dots in the center of the territories are the GIS-calculated centroids. The lines from the centroids to the linear and avoidance lines are the GIS-calculated minimum distances to the closest edges of the respective lines.
Source publication
Millions of kilometres of seismic lines have been created for hydrocarbon exploration in the boreal forest and their impact on songbirds is unknown. I conducted a replicated before–after control–impact (BACI) field experiment in southern Northwest Territories to evaluate the impact of 6 m wide seismic lines on songbirds. Territories of all birds on...
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... intersecting lines were cleared through each treat- ment plot. Each plot had one linear and one avoidance line cut at right angles, centered on the plot (Fig. 2). Lines were cleared 50 m beyond the study plots. This equates to a line density of 5.7 km per square kilometre of habitat, a moder- ate coverage of seismic lines. Intersection of two lines in a patch of forest, such as in this experiment, is common even when lower densities of seismic lines are present, as shown in Fig. 1 of Bayne et ...
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... spot mapping summary sheets (i.e., a computer was not used to draw minimum con- vex polygons). Territory centroids were calculated in the geographic information system (GIS) using a modified ver- sion of Centroid.Ave (http://arcscripts.esri.com). A territory was considered ''in'' if the centroid was within the plot boundary (e.g., territory 6 in Fig. 2 was ''in'' for count- Treatment study plot layout showing plot boundaries, two seismic lines, territories of one species, and some measurements used in analyses, all to scale. The plot is 350 m  350 m. The ver- tical striped line (L) is the linear seismic line referred to in the text, while the horizontal one is the avoidance line ...
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... index measure of the number of territories overlapping seismic lines was obtained using the GIS. Each cutline was arbitrarily subdivided into 6 m  6 m squares spaced every 10 m along the line's length (Fig. 2). The number of territo- ries intersecting each square (''hits'') was counted, by spe- cies. Using this technique, rather than simply counting a territory as overlapping or not, prevented bias for the territo- ries that barely contacted the seismic line. Territories cen- tered over the seismic line scored the most hits, and successively ...
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... was counted, by spe- cies. Using this technique, rather than simply counting a territory as overlapping or not, prevented bias for the territo- ries that barely contacted the seismic line. Territories cen- tered over the seismic line scored the most hits, and successively fewer hits applied to territories whose centers were farther from the line (Fig. 2). Without this technique, territories that barely touched the seismic lines (likely from chance when they were hand drawn) would have been weighted equally to those actually overlapping the seismic lines. Since I drew territories without foreknowledge of the seismic line location, this happened multiple times. Overlap numbers from a ...
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... areas within the study is valid, but the absolute area of each species' full territory is probably underestimated by the spot mapping technique, as only the singing territory would have been outlined (e.g., Mazerolle and Hobson 2004). No territories marked as ''partial'' were used in any area calculations or comparisons (e.g., territory 6 in Fig. 2 would be ...
Citations
... In comparison with polygonal disturbances created by wildfires and forestry, the geographic footprint of linear features is small; however, as they are widespread (>600,000 km; Pasher et al., 2013) and occur at high densities (up to 40 km/km 2 ; Stern et al., 2018), they have significant effects on forest fragmentation, contributing to 80% of forest edges (Pattison et al., 2016). Linear features impact the distribution and abundance of lichens, nonvascular and vascular plants (Finnegan, MacNearney, et al., 2018;MacDonald et al., 2020), as well as the distribution and movements of invertebrates and vertebrates (Machtans, 2006;Riva et al., 2018). Notably, linear features have had significant effects on the distribution and movements of large boreal mammals (Dickie et al., 2020;Dyer et al., 2002;, causing cascading impacts on predator-prey dynamics (DeMars & Boutin, 2018;Mumma et al., 2018). ...
Linear features are pervasive across the boreal forest of Canada, negatively impacting several wildlife species. Understanding how wildlife responds to different types and characteristics of linear features is necessary for coordinated landscape restoration. Currently, linear feature restoration is focused on recovering threatened woodland caribou (Rangifer tarandus) which may have unintended impacts on other boreal species like moose (Alces alces). Understanding how moose respond to different linear features can help ensure restoration is targeted and effective. We used GPS data from seven moose collected between 2008 and 2010 to investigate response to linear features and to determine how moose response was influenced by characteristics of linear features like the surrounding habitat and regeneration. At the landscape scale, moose selected areas closer to seismic lines when they were in areas with lower densities of seismic lines and higher densities of harvest blocks and wild-fires. This response was stronger during winter. Moose selected areas closer to pipelines when they were in areas with lower densities of other linear features, harvest blocks, and wildfires and were indifferent to roads at the population-level. At the fine scale, during winter, moose selected areas closer to seismic lines regardless of vegetation height or the surrounding habitat, but were indifferent to seismic lines during summer, and were indifferent to roads and pipelines during summer and winter. Combined, our results suggest that there are characteristics of seismic lines which make them attractive to moose regardless of the regeneration height on the seismic lines, providing further evidence that effective linear feature restoration will need to address the fact that linear features increase landscape permeability and provide forage for multiple boreal wildlife species. Our results also further illustrate the importance of considering how linear feature restoration efforts focused on caribou may shift the distribution of other boreal wildlife species. Ultimately, conservation efforts for threatened species should recognize that conservation efforts focused on one species may have unintended consequences for interacting species.
... The ovenbird is an area-sensitive forest interior species that is abundant in mature eastern forests and tends to be less abundant near forest edges (Bayne and Dale 2011, Wilson et al. 2012, Porneluzi et al. 2020. Several researchers have reported decreased abundance of area-sensitive forest specialists near corridor edges compared to interior forest (Rich et al. 1994, Machtans 2006). The eastern towhee and chestnut-sided warbler are early successional species commonly associated with young forest or edge habitat but differ in foraging strategy and location within the forest profile. ...
... Higher territory density is generally associated with higher quality habitat (Ortega and Capen 2002, Ingelfinger and Anderson 2004, Perot and Villard 2009), whereas territory proximity to corridor edge may indicate attractant, avoidant, or neutral behavioral responses (Villard et al. 2007). Proportion of territories that cross and span corridors is a measure of whether the corridor functions as a barrier to movement or is readily incorporated into the territory (Bayne et al. 2005a, b;Machtans 2006). ...
... Given the low crossing frequency of all species, our results indicate that even narrow forest roads (~5 m wide) appear to be a fragmenting feature for the forest birds we investigated; however, barrier effects were greatest for the forest interior ovenbird, which was least likely of all focal species to cross either corridor type. Ovenbirds exhibit similar behavior in the boreal forests of western Canada where they rarely cross narrow corridors such as 6-8-m-wide seismic lines (Bayne et al. 2005a, b;Machtans 2006) but incorporate low-impact seismic lines (2-3 m wide) into their territories (Bayne et al. 2005a). ...
Shale gas development occurs in forests of the Appalachian Basin within breeding habitat for forest songbirds. Development requires linear infrastructure (e.g., pipelines, gas access roads) that fragments habitat and reduces core forest. Collocation is a mitigation practice that sites new pipelines adjacent to existing surface disturbance such as forest roads; it reduces core forest loss but may have associated ecological costs, defined as negative effects on native species and ecosystems. We conducted a paired sampling design between forest roads and collocated pipelines (expanded gas access roads collocated with pipelines) to evaluate ecological costs to forest songbirds in 2013 in Pennsylvania, USA. We surveyed 4 focal songbird species: 3 territorial species that varied in habitat requirements and the non‐territorial brown‐headed cowbird ( Molothrus ater ), an obligate brood parasite. We used spot mapping to survey focal species within linear corridors and the adjacent mature forest. Territory density of forest interior ovenbirds ( Seiurus aurocapilla ) was significantly lower on collocated pipelines (5.1 fewer territories per 10 ha) compared to forest road sites. We found no effect of collocation on territory density for the early successional species, eastern towhee ( Pipilo erythrophthalmus ) and chestnut‐sided warbler ( Setophaga pensylvanica ). Territories of all 3 territorial focal species crossed collocated pipeline sites less frequently than forest roads (ovenbird: 16%, eastern towhee: 14%, chestnut‐sided warbler: 31%) and the barrier effect increased with increasing corridor width. In contrast, brown‐headed cowbird abundance was 15 times greater at collocated pipelines compared to forest roads, suggesting that wider gas corridors provide enhanced access routes for cowbirds. Our study indicates the expansion of forest roads to collocated pipelines exacerbates the negative ecological effects already present with the existing road including increased edge avoidance by a forest interior species, greater barrier effects for all 3 territorial forest songbirds, and increased access for brown‐headed cowbirds into core forest. We support collocation as a mitigation strategy but emphasize restricting overall corridor width to reduce the additional ecological costs associated with this practice.
... Industrial activities and oil sands production in the Peace-Athabasca region, located principally in northeastern Alberta, are associated with the fourth largest crude oil reserves worldwide (Government of Alberta 2022). While geographical (Dyer et al. 2001(Dyer et al. , 2002Bayne et al. 2005;Machtans 2006;Jordaan 2012) and hydrological (Beck et al. 2014;Schwalb et al. 2015) effects are well documented, it is the emissions from oil sands operations and subsequent contaminant deposition, which can be detected nearly 1000 km away from the source (Schindler 2014), that underscore many major wildlife (Hodson 2013;Lundin et al. 2015;Rodríguez-Estival and Smits 2016;Fernie et al. 2018;Parrott et al. 2018) and public health (Gosselin et al. 2010) concerns.A major point of contention is the magnitude and type of airborne emissions (e.g., carbon monoxide, metals, oxides of sulfur and nitrogen, particulate matter, polycyclic aromatic compounds (PACs), ozone, and volatile organic compounds; Gosselin et al. 2010;Hodson 2013;Li et al. 2017). There is a considerable range of evidence detailing the scope, complexity, and impacts of airborne emissions emanating from oil sands development (Gosselin et al. 2010; Government of Canada 2022a), but for the purposes of this paper, we focus on the presence of heavy metals with known health impacts and commonly analyzed in the wildlife health literature (i.e., arsenic, cadmium, chromium, lead, mercury, methylmercury, and nickel). ...
Oil production activities have remained contentious in Canada due to the risk of contaminant exposure and environmental impacts. However, despite recent advances in monitoring, there is a lack of information on contaminant exposure and its associated impacts for many species at risk. The threat from contaminants to wood bison ( Bison bison athabascae) in the Peace-Athabasca region, located principally in northeastern Alberta, is of particular concern, given the small size of the at-risk herds and the potential combined impacts of various stressors, including contaminants, disease, and climate change. Here, we review the available literature on contaminants in wood bison in the Peace-Athabasca region, extracting information on objectives, study design, location, contaminants, and analytic methods. We found six articles that assessed contaminants in wood bison and showed that, in the oil sands region, the species is exposed to a multitude of chemical contaminants. In particular, heavy metals, including arsenic, cadmium, lead, and inorganic mercury, were analyzed most often in bison kidney, liver, and muscle tissue. We also provide a comparison of the type and levels of heavy metals in wood bison and moose ( Alces alces). We found that articles on wood bison were dated relative to moose (i.e., mostly pre-1990s) and that fewer heavy metals and tissue types were assessed. Lastly, we discuss the gaps in knowledge on select heavy metals in these species and the known effects on human health. Overall, our results suggest that more research and monitoring are needed to understand the threats to wood bison, interacting and cumulative effects, and potential concerns related to human health and well-being for communities that rely on wood bison as a traditional food source.
... In general, this work supports other findings that impacts from roads differ from cutlines (wide linear or 3D seismic features) and cannot be directly extrapolated (Linke et al. 2008). Whereas cutlines create greater edge per unit area than other features (Linke et al. 2008, Riva and Nielsen 2020, they may also create softer edges that are not perceived by these two species as structurally distinct to natural openings (Machtans 2006). Additionally, factors including resilience and threshold effects may contribute to the relatively weak influence of temporary development features on Dark-eyed Junco and Palm Warbler occurrence. ...
Demand for petroleum products is causing habitat loss, alteration, and fragmentation of boreal forests in western Canada. Associated exploratory and extraction activities from in situ oil sands leave a network of (1) permanent polygonal features (e.g., processing facilities, extraction sites, gravel pits); (2) permanent linear features (e.g., roads, pipelines); (3) temporary polygonal features (e.g., exploratory well sites); and (4) temporary linear features, (e.g., winter roads, seismic lines). We examined the impact of these different types of disturbances on the occurrence of a generalist, the Dark-eyed Junco (Junco hyemalis) and a peatland specialist, the Palm Warbler (Setophaga palmarum) for an in situ development-lease area in northeast Alberta, Canada. Our goal was, first, to determine if energy development features have positive, negative, or neutral effects on species occurrence, beyond the amount of habitat disturbed, and second, to identify the relative impact of different types of energy features. Permanent polygonal features negatively influenced both species, decreasing the odds of occurrence for Dark-eyed Juncos by 0.63 times and 0.44 times for Palm Warblers for every 10% increase in percent area. However, permanent linear features increased odds of occurrence for Dark-eyed Juncos by 1.73 times and Palm Warblers by 3.93 times. We speculate that permanent linear features increase vegetation heterogeneity or influence insect-prey availability through edge effects. Although permanent polygonal and linear features had opposite effects (negative and positive, respectively), they had a similar relative effect on occurrence for both species. There were no effects of temporary polygonal or linear features on occurrence for either species examined here. Whereas our understanding of birds in boreal peatland forests is limited, these results are consistent with studies that suggest permanent linear features have more substantive local scale impacts than temporary disturbances.
... Companies have reduced the width of seismic lines from an average of 8 meters to <3 meters, and far greater care is taken to construct lines during periods of the year that reduce disturbance to the forest floor. Despite these advancements, research has found correlations between wildlife behavior /abundance and seismic line density (Bayne et al. 2005a, Machtans 2006, Lankau et al. 2013. While less well understood, there is evidence that changes in food availability, competition, and predation may be the mechanisms underlying these patterns (James and Stuart-Smith 2000, Machtans 2006, Lankau et al. 2013, Riva et al. 2018a). ...
... Despite these advancements, research has found correlations between wildlife behavior /abundance and seismic line density (Bayne et al. 2005a, Machtans 2006, Lankau et al. 2013. While less well understood, there is evidence that changes in food availability, competition, and predation may be the mechanisms underlying these patterns (James and Stuart-Smith 2000, Machtans 2006, Lankau et al. 2013, Riva et al. 2018a). ...
... Narrower low-impact seismic lines, or seismic lines with greater vegetation, were more likely to be included within an Ovenbird territory (Bayne et al. 2005a, Lankau et al. 2013). However, Machtans (2006) and Bayne et al. (2005b) found that ground and shrub nesting species (including the Ovenbird) showed an increase in territory size when their territory included a seismic line regardless of seismic line width. This increase in territory size was larger than the corresponding area disturbed by the seismic line, suggesting a disproportionate increase in area may be required to compensate for diminished resources on the seismic line per se. ...
Seismic lines have an extensive footprint in Canada's western boreal forest that alter habitat conditions for many species. Seismic lines exist within a range of seral states due to changing practices and regulations related to operational needs. Forest regeneration is often hindered on seismic lines as they are frequently repurposed for recreational or alternative industrial uses. The Canada Warbler (Cardellina canadensis) is a Neotropical migrant songbird that relies on Canada's boreal region for breeding habitat. As a species at risk both federally (Threatened) and provincially within Alberta (Sensitive), their response to seismic lines has been a significant gap in our understanding of human impacts on the boreal breeding grounds. We used playback surveys along seismic lines within Canada Warbler habitat to identify individual territories. Arrays of autonomous recording units (ARU) were deployed to conduct acoustic source localization (ASL) and map the locations of territorial singing events. Canada Warblers avoided seismic lines with little to no woody vegetation but were more likely to be observed near seismic lines when shrub cover on the line increased. Canada Warblers used the seismic line and the edge environment but did not select for the line when compared to its availability. Use was more evenly distributed across the seismic line as shrub density on the line increased. However, even the most overgrown seismic lines were still perceived as a feature and influenced Canada Warbler space use and behavior. For Canada Warblers, ensuring that seismic lines in old-growth deciduous forests are allowed to recover by reducing reuse of lines should mitigate population level impacts, but more work is needed to assess how population dynamics are influenced by seismic lines and other energy sector disturbances.
... However, there is a rise of concern about environmental impacts resulting from land disturbances related to oil sands production. A number of studies have demonstrated that land disturbances can have long-term effects on the population of various species, ranging from songbirds to carnivores (Bayne et al., 2005;Dyer et al., 2001;Machtans, 2006;Nielsen et al., 2007). Therefore, the identification, mapping and monitoring of land disturbances and potential risks associated with mining activities at local and regional scales becomes a requirement for sustainable mining development (Erzurumlu and Erzurumlu, 2015). ...
Fine-scale land disturbances due to mining development modify the land surface cover and have cumulative detrimental impacts on the environment. Understanding the distribution of fine-scale land disturbances related to mining activities, such as oil well sites, in mining regions is of vital importance to sustainable mining development. For efficient mapping, automated identification and extraction of the oil well sites using high-resolution satellite images are required. In this work, we proposed the Oil Well Site extraction (OWS) Mask R-CNN based on the original Mask R-CNN (Region-based Convolutional Neural Networks), to accurately extract well sites using multi-sensor remote sensing images. For improvement of mapping efficiency, two modifications were made to Mask R-CNN: (1) replacing the backbone of Mask R-CNN with D-LinkNet, and (2) adding a semantic segmentation branch to Mask R-CNN to force the whole network to focus on the relationship between line objects and oil well sites. As imagery data were from multiple sensors (RapidEye 2/3 and WorldView 3), a pre-trained Residual Channel Attention Network (RCAN) was applied to super-resolve the images with different resolutions. Several key spatial features, such as nearby roads and area size, have also been used in the oil well site mapping process. The experimental results indicate that our OWS Mask R-CNN considerably improves the average precision (AP) and the F 1 score of Mask R-CNN from 51.26% and 25.7% to 60.93% and 61.59%, respectively.
... Effects of seismic line disturbances include altered habitat use by birds (Bayne et al., 2005;Machtans, 2006;Ashenhurst and Hannon, 2008;Lankau et al., 2013), butterflies (Riva et al., 2018a), and mammals (Dyer et al., 2001;Tigner et al., 2014;Tigner et al., 2015;Fisher and Burton, 2018;Dickie et al., 2020). Seismic lines are used as travel corridors by predators such as wolves (Latham et al., 2011;McKenzie et al., 2012;Dickie et al., 2017) thereby influencing predation rates of woodland caribou (James and Stuart-Smith, 2000;Mumma et al., 2017;DeMars and Boutin, 2018), which is a species of conservation concern (COSEWIC, 2002). ...
Ecological impacts of linear anthropogenic disturbances may be underestimated due to edge effects extending into adjacent forests. Seismic lines are the most pervasive linear disturbance associated with oil and gas development in the boreal forests of western North America. The width and orientation of seismic lines may influence microclimatic edge effects that could alter biotic responses, including tree recruitment. We examined light intensity, air temperature, relative humidity, and tree regeneration within seismic lines and adjacent forests to: (1) compare abiotic conditions between wide (6–8 m) and narrow (3–4 m) seismic lines; (2) quantify microclimatic edge effects of seismic lines of different widths and orientations; and (3) relate patterns in tree regeneration density to local patterns in the abiotic environment. We sampled interior forests and 24 seismic lines that were wide or narrow and orientated east-west or north-south in poor mesic ecosites of northeast Alberta, Canada. Microclimatic conditions in seismic line centres were generally intermediate between interior forest and well pads, with narrow seismic lines more similar to interior forest and wide seismic lines more similar to well pads. Light intensity on wide seismic line centres was at least 1.5 times higher than on narrow seismic line centres and up to 3.8 times higher than interior forest. Edge effects on light intensity extended up to 10 m into the forest adjacent to wide lines, but were restricted to the forest edge (at the interface) of narrow lines. Compared to interior forest, day temperature was up to 2.8 °C and 0.8 °C higher at edges of wide and narrow seismic lines, respectively. Relative humidity during the day was up to 7.3% and 3% lower at the edges of wide and narrow seismic lines, respectively, as compared to interior forest. At night, wide seismic line centres were up to 1.7 °C cooler and up to 8.2% more humid than narrow seismic line centres. Tree regeneration was highest where light intensity was highest (the centre of wide north-south seismic lines) and a 10-fold increase in light intensity resulted in 5.8 times more regenerating trees. This study reveals that seismic line width and orientation affect abiotic factors within the linear disturbance and up to 10 m into the adjacent forest. Edge effects on the microclimate of seismic lines were most pronounced in wider seismic lines and along north (south-facing) forest edges. These findings provide a better understanding of the abiotic factors influencing biotic responses to linear anthropogenic disturbances.
... Our results of negative seismic line relationships in both landscapes for ground and overwater nesters, corroborate other research on wildlife and seismic lines. Although relationships with seismic lines have not been examined for waterfowl until now, negative relationships have been observed with other species (Ovenbirds, Seiurus aurocapilla, Bayne et al. 2005, Machtans 2006; woodland caribou, Rangifer tarandus caribou, Dyer et al. 2001, but see Dyer et al. 2002). These patterns have been attributed to increased predation risk, with seismic lines serving as travel corridors, potentially resulting in greater predator aggregation or increased hunting success (James 1999, James and Stuart-Smith 2000, Smith 2004, Tigner 2012. ...
... Beginning around 1980, seismic line construction width was gradually reduced and now is typically ~2-3 m wide (low-impact lines), typically cut by hand or small machinery (Alberta Environment and Parks 2010). Little research has attempted to disentangle varying effects of conventional vs low-impact seismic lines (but see, Machtans 2006 andVan Rensen et al. 2015) or time since seismic line construction. Our results show that population trajectory for overwater nesters in high seismic line density segments began to increase slightly while that of ground nesters continued to decline around the time low-impact lines were implemented (Fig. A3.3), and so we suggest this change in practice could impact guilds differently but does not appear to have appreciably altered relationships with duck populations. ...
Impacts of anthropogenic disturbance on duck populations in the boreal forest is largely unknown but hypothesized to negatively influence abundance through top-down and bottom-up processes. We examined relationships between population trajectory of duck pairs and anthropogenic disturbances in the Boreal Plains ecozone of western Canada by first controlling for habitat and then assessing whether population trends were related to density of seismic lines, pipelines, roads, and well sites, and distance to agriculture to help focus conservation efforts on the most limiting changes. We also evaluated whether these relationships differed in agriculture encroached vs. unencroached landscapes; distance to agriculture was assessed in unencroached landscapes. Pair counts (1960-2007) obtained from the Waterfowl Breeding Population and Habitat Survey were pooled into nesting guilds (cavity, ground, and overwater). All anthropogenic disturbance features were time invariant. Annual moisture data was used to control for effects of annual variation in breeding season weather. Variation in relative magnitude and direction of effect size indices among anthropogenic disturbances depended on both landscape and nesting guild. Overall, majority of negative relationships occurred with seismic lines and pipelines, while distance to agriculture was positive. Population trends for ground nesters, which suggest overall declines, tended be most negative in regions with high seismic line and well pad density in encroached landscapes and with high seismic line and pipeline density in unencroached landscapes. Cavity nester population trends were generally positive throughout the study area but were lowest in unencroached landscapes farthest from agriculture. Overwater nester trends were generally lowest in encroached landscapes with high densities of seismic lines, roads, and well pads and in unencroached landscapes with high densities of seismic lines, pipelines, and roads. Although our work suggests that anthropogenic disturbances, particularly seismic and pipelines, may merit further consideration as foci for conservation, additional research is needed to quantify demographic implications.
... Energy sector development often occupies a relatively small footprint on landscapes, but results in a disproportionate amount of habitat fragmentation due to the increase in associated linear infrastructure (i.e., roads, transmission lines and pipelines; Bayne and Dale 2011). The resulting proliferation of edge habitats reduces suitability of impacted landscapes for area-sensitive species, as evidenced by declines in edge-avoiding birds following development of seismic lines in boreal forests (Bayne et al. 2005;Machtans 2006), and oil and gas well pads and roadways in sagebrush steppe (Gilbert and Chalfoun 2011;Mutter et al. 2015) and grasslands (Thompson et al. 2015;Nenninger and Koper 2018). Unconventional shale gas development is still relatively new to the eastern USA, and much is still unknown about the biological impacts on forest ecosystems. ...
ContextSince 2005, unconventional gas development has rapidly altered forests across the Marcellus-Utica shale basin in the central Appalachian region of the eastern United States, an area of high conservation value for biodiversity. Much is still unknown about ecological impacts of associated land cover change.Objectives
Our goal was to identify threshold responses among bird species and habitat guilds to (1) overall forest loss and fragmentation in affected landscapes, and (2) distance from anthropogenic disturbance, both related and unrelated to shale gas.Methods
We conducted 2589 bird surveys at 190 sites across this region, and quantified community-level and species-specific thresholds relating to forest cover and distance to anthropogenic disturbance, using Threshold Indicator Taxa Analysis (TITAN).ResultsForest interior species decreased abruptly in abundance and frequency of occurrence above a threshold of 17.0% overall forest loss, while early successional and synanthropic species increased abruptly above 30.5–36.5% forest loss, respectively. Broad quantile intervals around responses to distance from anthropogenic disturbance suggest these were not sharp threshold responses, but more gradual or linear responses. Among forest interior species evaluated, 48.1% increased in abundance farther from shale gas development, while 55.6% of early successional and synanthropic species decreased.Conclusions
We found evidence of avian threshold responses to overall forest loss and fragmentation in affected landscapes across the Marcellus-Utica shale region. Our results suggest that efforts to avoid shale gas development in regional core forests—particularly those still retaining ≥ 83% forest cover—can reduce negative effects on area-sensitive, forest interior dependent species.
... Energy sector disturbance often occupies a relatively small proportion of land cover, but creates a disproportionate amount of edge habitat from a proliferation of linear infrastructure (Bayne and Dale 2011). Increased edge creation from energy development degrades habitat suitability for some edgeavoiding species, as evidenced by declines in area-sensitive birds in response to seismic lines in boreal forests (Bayne et al. 2005, Machtans 2006, and oil and gas development in sagebrush steppe (Gilbert andChalfoun 2011, Mutter et al. 2015) and grasslands (Thompson et al. 2015, Nenninger andKoper 2018). ...
... less abundant near one or more types of conventional oil and gas infrastructure (Bayne et al. 2016). In particular, Ovenbirds showed negative responses to seismic lines in boreal forests (Bayne et al. 2005, Machtans 2006). In the western United States, sagebrush obligate songbirds declined with increasing densities of oil and gas well pads (Gilbert and Chalfoun 2011) and roads associated with natural gas development (Mutter et al. 2015). ...
Unconventional shale gas development is a rapidly expanding driver of forest loss and fragmentation in the central Appalachian region. We evaluated the relationship between breeding passerine abundances and distance from shale gas development at a long-term (2008-2017) study site in northern West Virginia, USA. We examined responses of 27 species within 3 habitat guilds: forest interior, early successional, and synanthropic. More than half of the species evaluated showed sensitivity to distance from unconventional shale gas infrastructure (e.g., well pads, access roads, pipelines). Five forest interior species occurred in greater abundances farther from shale gas development , whereas 3 forest interior gap specialists increased in abundance closer to shale gas. Early successional and synanthropic species, including the nest-parasitic Brown-headed Cowbird (Molothrus ater), generally occurred in greater abundances closer to shale gas infrastructure. We used interpolated distributions of 4 focal species to assess their spatial response to unconventional shale gas development over time. Our results indicate that breeding pas-serine distributions and community composition are changing with forest disturbance driven by unconventional shale gas energy development.
