Julia Gómez-Catasús, L. Carrascal, V. Moraleda, José Colsa, Fernando Garcés, C. Schuster
{"title":"影响电线上鸟类碰撞死亡率差异低估的因素:加那利群岛的案例研究","authors":"Julia Gómez-Catasús, L. Carrascal, V. Moraleda, José Colsa, Fernando Garcés, C. Schuster","doi":"10.13157/arla.68.1.2021.ra5","DOIUrl":null,"url":null,"abstract":"Carcass counts notably underestimate avian collision rates due to three main bias sources: imperfect detection, carcass removal by scavengers and carcass dispersion in unsearched areas. We assessed these sources of bias at electric lines of two Canary Islands, Lanzarote and Fuerteventura, quantifying the factors influencing them. We also carried out a cost-effectiveness assessment of carcass search done perpendicularly to electric line axis. We surveyed 230km of three types of electric lines (high-voltage, medium voltage and telephone lines) during three periods (July 2015, November-December 2015 and March 2016) searching for collision fatalities (N = 431), recording the species, the carcass distance from the electric line, mean cable height, carcass detection distance and decomposition state. In addition, we carried out a disappearance rate experiment to estimate carcass removal by scavengers. A generalised least squares model was used to analyse dispersion distance of carcass from electric lines, in relation to species body mass, mean cable height and line typology. Detection probability functions were fitted to estimate carcass detectability, incorporating body mass, decomposition state and habitat structure as covariates. A Generalised Mixed-Effects model was carried out to analyse carcass disappearance in relation to time elapsed since carcass placement, carcass size, season and island. Dispersion distance decreased with body mass and increased with cable height, being further at high-voltage lines. Overall, detection probability was 0.134, increasing with carcass size, decreasing with decomposition state and being lower in rocky areas which offered a significant challenge when walking through rough terrain. Disappearance rates differed between islands probably due to differences in avian scavenger abundance, increased with time elapsed and decreased with bird size. This study provides correction factors to obtain unbiased estimates of avian mortality rates within sparsely vegetated landscapes. Moreover, it identifies a 27m threshold distance at which the cost-effectiveness of searching for carcasses is optimised.—Gomez-Catasus, J., Carrascal, L.M., Moraleda, V., Colsa, J., Garces, F. & Schuster, C. (2021). Factors affecting differential underestimates of bird collision fatalities at electric lines: a case study in the Canary Islands. Ardeola, 68: 71-94.","PeriodicalId":55571,"journal":{"name":"Ardeola-International Journal of Ornithology","volume":"19 1","pages":"71-94"},"PeriodicalIF":1.4000,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"13","resultStr":"{\"title\":\"Factors Affecting Differential Underestimates of Bird Collision Fatalities at Electric Lines: A Case Study in the Canary Islands\",\"authors\":\"Julia Gómez-Catasús, L. Carrascal, V. Moraleda, José Colsa, Fernando Garcés, C. Schuster\",\"doi\":\"10.13157/arla.68.1.2021.ra5\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Carcass counts notably underestimate avian collision rates due to three main bias sources: imperfect detection, carcass removal by scavengers and carcass dispersion in unsearched areas. We assessed these sources of bias at electric lines of two Canary Islands, Lanzarote and Fuerteventura, quantifying the factors influencing them. We also carried out a cost-effectiveness assessment of carcass search done perpendicularly to electric line axis. We surveyed 230km of three types of electric lines (high-voltage, medium voltage and telephone lines) during three periods (July 2015, November-December 2015 and March 2016) searching for collision fatalities (N = 431), recording the species, the carcass distance from the electric line, mean cable height, carcass detection distance and decomposition state. In addition, we carried out a disappearance rate experiment to estimate carcass removal by scavengers. A generalised least squares model was used to analyse dispersion distance of carcass from electric lines, in relation to species body mass, mean cable height and line typology. Detection probability functions were fitted to estimate carcass detectability, incorporating body mass, decomposition state and habitat structure as covariates. A Generalised Mixed-Effects model was carried out to analyse carcass disappearance in relation to time elapsed since carcass placement, carcass size, season and island. Dispersion distance decreased with body mass and increased with cable height, being further at high-voltage lines. Overall, detection probability was 0.134, increasing with carcass size, decreasing with decomposition state and being lower in rocky areas which offered a significant challenge when walking through rough terrain. Disappearance rates differed between islands probably due to differences in avian scavenger abundance, increased with time elapsed and decreased with bird size. This study provides correction factors to obtain unbiased estimates of avian mortality rates within sparsely vegetated landscapes. Moreover, it identifies a 27m threshold distance at which the cost-effectiveness of searching for carcasses is optimised.—Gomez-Catasus, J., Carrascal, L.M., Moraleda, V., Colsa, J., Garces, F. & Schuster, C. 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Factors Affecting Differential Underestimates of Bird Collision Fatalities at Electric Lines: A Case Study in the Canary Islands
Carcass counts notably underestimate avian collision rates due to three main bias sources: imperfect detection, carcass removal by scavengers and carcass dispersion in unsearched areas. We assessed these sources of bias at electric lines of two Canary Islands, Lanzarote and Fuerteventura, quantifying the factors influencing them. We also carried out a cost-effectiveness assessment of carcass search done perpendicularly to electric line axis. We surveyed 230km of three types of electric lines (high-voltage, medium voltage and telephone lines) during three periods (July 2015, November-December 2015 and March 2016) searching for collision fatalities (N = 431), recording the species, the carcass distance from the electric line, mean cable height, carcass detection distance and decomposition state. In addition, we carried out a disappearance rate experiment to estimate carcass removal by scavengers. A generalised least squares model was used to analyse dispersion distance of carcass from electric lines, in relation to species body mass, mean cable height and line typology. Detection probability functions were fitted to estimate carcass detectability, incorporating body mass, decomposition state and habitat structure as covariates. A Generalised Mixed-Effects model was carried out to analyse carcass disappearance in relation to time elapsed since carcass placement, carcass size, season and island. Dispersion distance decreased with body mass and increased with cable height, being further at high-voltage lines. Overall, detection probability was 0.134, increasing with carcass size, decreasing with decomposition state and being lower in rocky areas which offered a significant challenge when walking through rough terrain. Disappearance rates differed between islands probably due to differences in avian scavenger abundance, increased with time elapsed and decreased with bird size. This study provides correction factors to obtain unbiased estimates of avian mortality rates within sparsely vegetated landscapes. Moreover, it identifies a 27m threshold distance at which the cost-effectiveness of searching for carcasses is optimised.—Gomez-Catasus, J., Carrascal, L.M., Moraleda, V., Colsa, J., Garces, F. & Schuster, C. (2021). Factors affecting differential underestimates of bird collision fatalities at electric lines: a case study in the Canary Islands. Ardeola, 68: 71-94.
期刊介绍:
Ardeola: International Journal of Ornithology is the scientific journal of SEO/BirdLife, the Spanish Ornithological Society. The journal had a regional focus when it was first published, in 1954. Since then, and particular during the past two decades, the journal has expanded its thematic and geographical scope. It is now a fully international forum for research on all aspects of ornithology. We thus welcome studies within the fields of basic biology, ecology, behaviour, conservation and biogeography, especially those arising from hypothesis-based research. Although we have a long publication history of Mediterranean and Neotropical studies, we accept papers on investigations worldwide.
Each volume of Ardeola has two parts, published annually in January and July. The main body of each issue comprises full-length original articles (Papersand Review articles) and shorter notes on methodology or stimulating findings (Short Communications). The publication language is English, with summaries, figure legends and table captions also in Spanish. Ardeolaalso publishes critical Book Reviewsand PhD-Dissertation Summaries; summarising ornithological theses defended in Spain. Finally there are two Spanish-language sections, Ornithological News; summarising significant recent observations of birds in Spain, and Observations of Rare Birds in Spain, the annual reports of the Spanish Rarities Committee.