Effects of Disturbance Associated with Natural Gas Extraction on the Occurrence of Three Grassland Songbirds

• Published in: Avian conservation and ecology Vol. 6; no. 1; p. 7
• Main Authors: Hamilton, Laura E., Dale, Brenda C., Paszkowski, Cynthia A.
• Format: Journal Article
• Language: English; French
• Published: Resilience Alliance 01.06.2011
• Subjects: anthropogenic disturbance; Anthus spragueii; Calcarius ornatus; Chestnut-collared Longspur; grassland; modeling; natural gas; Passerculus sandwichensis; Savannah Sparrow; Sprague's Pipit; Canada, Alberta
• ISSN: 1712-6568; 1712-6568
• DOI: 10.5751/ACE-00458-060107

Despite declines in the grassland bird guild and increasing rates of natural gas extraction on the Canadian prairies, relatively few studies have examined the effects of well sites and related infrastructure on these species. We conducted point counts on Canadian Forces Base Suffield, Alberta to investigate the effects of two well densities (high: 16 wells/2.59km super(2), low: 9 wells/2.59km super(2)) on Savannah Sparrow (Passerculus sandwichensis), Chestnut-collared Longspur (Calcarius ornatus), and Sprague's Pipit (Anthus spragueii) occurrence and abundance. Additionally, model building was employed to determine if landscape features, i.e., soil type, elevation, and topography, along with well density and anthropogenic disturbance to natural vegetation, i.e., the combined areas affected by wells, pipelines, trails, and roads, could predict the occurrence of the three species. For Savannah Sparrows, occurrence and abundance were higher in areas with high well densities compared with low well densities, reflecting the species' general tolerance of human disturbances. Chestnut-collared Longspurs were ubiquitous in the study area and abundance was not related to well density. Models for this species performed poorly and failed to predict occurrence accurately. Models for Sprague's Pipit were the strongest and showed that this species' occurrence was negatively related to anthropogenic disturbance. For all three species, landscape features had low predictive power. Our results indicate that disturbance caused by well sites and related infrastructure affect occurrence of some species and should be incorporated into conservation strategies for grassland birds, especially as undisturbed grasslands become candidates for energy development.Original Abstract: Malgre le declin des especes de la guilde des oiseaux de prairie et le taux accru d'extraction de gaz naturel dans les Prairies canadiennes, relativement peu d'etudes ont examine l'effet des sites de puits et d'infrastructures connexes sur ces especes. Nous avons effectue des denombrements par points d'ecoute sur la base des forces canadiennes Suffield, en Alberta, afin d'etudier l'effet de deux densites de puits (elevee: 16 puits/2,59 km super(2); faible: 9 puits/2,59 km super(2)) sur l'occurrence et l'abondance du Bruant des pres (Passerculus sandwichensis), du Plectrophane a ventre noir (Calcarius ornatus) et du Pipit de Sprague (Anthus spragueii). Nous avons egalement construit des modeles afin de determiner si les caracteristiques du paysage (type de sol, altitude et topographie), de meme que la densite des puits et les modifications anthropiques occasionnees a la vegetation naturelle (l'ensemble des endroits touches par les puits, pipelines, chemins et routes), permettaient de prevoir l'occurrence de ces trois especes. Chez le Bruant des pres, l'occurrence et l'abondance etaient superieures aux endroits ou la densite de puits etait elevee, conformement a la tolerance au derangement humain observee chez cette espece, en general. L'abondance du Plectrophane a ventre noir, espece ubiquiste dans notre aire d'etude, n'etait pas liee a la densite de puits. Les modeles pour cette espece ne donnaient pas de bons resultats et n'ont pas su prevoir l'occurrence avec exactitude. Quant aux modeles pour le Pipit de Sprague, ils se sont averes les plus puissants d'entre tous et ont montre que l'occurrence de cette espece etait negativement reliee aux derangements anthropiques. Chez l'ensemble des trois especes, les caracteristiques du paysage n'etaient pas de bonnes variables pour prevoir leur occurrence et leur abondance. Nos resultats indiquent que le derangement attribue aux sites de puits et aux infrastructures connexes affecte l'occurrence des certaines especes et devrait etre pris en consideration dans les strategies de conservation d'oiseaux de prairie, particulierement si des prairies vierges se retrouvent dans la mire du developpement energetique.