% pubman genre = article
@article{item_3361748,
title = {{Deriving observation distances for camera trap distance sampling}},
author = {Zuleger, Annika M. and Holland, Ruben and K{\"u}hl, Hjalmar S.},
language = {eng},
issn = {0141-6707; 1365-2028},
doi = {10.1111/aje.12959},
publisher = {Wiley Blackwell},
year = {2022},
abstract = {{Camera trap distance sampling (CTDS)o is a recently developed survey method to estimate animal abundance from camera trap data for unmarked populations. It re-quires the estimation of camera-animal observation distances, which previously was done by comparing animal positions to reference labels at predefined intervals. Here, we test a photogrammetry approach to derive camera-animal observation distances. We applied both, the reference label and photogrammetry approaches to five un-gulate species varying widely in body size (Giraffa camelopardalis, Equus grevyi, Oryx dammah, Kobus megaceros and Eudorcas thomsonii) and one ground-dwelling bird spe-cies (Numida meleagris) inhabiting a large enclosure and estimated their density with CTDS. Both procedures provided highly correlated observation distances ($\varrho${\textequals} 0.99, p{\textless} 0.001). A paired t test revealed a minor but significantly higher mean of the photo-grammetry approach (MD {\textequals} 0.28 m, p{\textless} 0.001). This, however, seems negligible as for analyses, distances were grouped in intervals of 2 to 5 metres. In general, estimated animal abundance was close to the true number of individuals in the enclosure for both approaches, with the exception of zebra, whose density was underestimated. The photogrammetry approach offers an alternative approach for deriving camera-animal observation distances and is particularly useful for application in open habi-tats, with little occlusion of animals.}},
abstract = {{Le distance sampling par pi{\`e}ge photographique (Camera trap distance sampling ou {\textless}br{\textgreater}CTDS en anglais) est une technique de recensement d{\'e}velopp{\'e}e r{\'e}cemment qui {\textless}br{\textgreater}permet d{\textquoteright}estimer l{\textquoteright}effectif de populations animales non marqu{\'e}es avec des pi{\`e}ges {\textless}br{\textgreater}photographiques. Cette technique requiert l{\textquoteright}estimation de la distance entre le pi{\`e}ge {\textless}br{\textgreater}photographique et l{\textquoteright}animal observ{\'e}, ce qui {\'e}tait pr{\'e}c{\'e}demment obtenu en comparant {\textless}br{\textgreater}la position de l{\textquoteright}animal {\`a} des points de r{\'e}f{\'e}rence plac{\'e}s {\`a} des intervalles pr{\'e}d{\'e}finis. {\textless}br{\textgreater}Ici nous testons une approche de photogramm{\'e}trie pour estimer les distances entre les pi{\`e}ges photographiques et les animaux observ{\'e}s. Nous avons appliqu{\'e} les deux approches, points de r{\'e}f{\'e}rence et photogramm{\'e}tries, {\`a} cinq esp{\`e}ces d{\textquoteright}ongul{\'e}s de {\textless}br{\textgreater}tailles diff{\'e}rentes (Giraffa camelopardalis, Equus grevyi, Oryx dammah, Kobus megaceros {\textless}br{\textgreater}et Eudorcas thomsonii) ainsi qu{\textquoteright}une esp{\`e}ce d{\textquoteright}oiseau (Numida meleagris) vivant dans {\textless}br{\textgreater}un espace cl{\^o}tur{\'e} et avons estim{\'e} leur densit{\'e}s de populations avec le CTDS. Les {\textless}br{\textgreater}deux m{\'e}thodes ont fourni des distances d{\textquoteright}observations fortement corr{\'e}l{\'e}es ($\varrho$ {\textequals} {\textless}br{\textgreater}0.99, p {\textless} 0.001). Un t-test jumel{\'e} a r{\'e}v{\'e}l{\'e} une moyenne l{\'e}g{\`e}rement plus {\'e}lev{\'e}e et {\textless}br{\textgreater}significative pour la technique de photogramm{\'e}trie (MD {\textequals} 0.28 m, p {\textless} 0.001). Celle-ci {\textless}br{\textgreater}est n{\'e}anmoins n{\'e}gligeable dans la mesure o{\`u}, pour les analyses, les distances {\'e}taient {\textless}br{\textgreater}group{\'e}es dans des intervalles allant de 2 {\`a} 5 m{\`e}tres. En r{\`e}gle g{\'e}n{\'e}rale, les estimations {\textless}br{\textgreater}d{\textquoteright}abondances {\'e}taient proche du nombre r{\'e}el d{\textquoteright}individus dans l{\textquoteright}enclos, et ce pour les {\textless}br{\textgreater}deux techniques, avec l{\textquoteright}exception des z{\`e}bres pour lesquels les densit{\'e}s {\'e}taient sous- {\textless}br{\textgreater}estim{\'e}es. La technique de photogramm{\'e}trie offre une alternative pour d{\'e}river les {\textless}br{\textgreater}distances entre les pi{\`e}ges photographiques et les animaux observ{\'e}s et pourrait {\^e}tre {\textless}br{\textgreater}particuli{\`e}rement utile dans des habitats ouverts o{\`u} les animaux sont peu cach{\'e}s.}},
journal = {{African Journal of Ecology}},
volume = {60},
number = {3},
pages = {423--432},
}