Validation of observer and aircraft calibration for aerial surveys of animals
Validation of observer and aircraft calibration for aerial surveys of animals
复制标题
动物航空调查的观察者和飞机校准验证
DOI:
10.1111/j.1365-2028.2001.00268.x
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发表时间:
2001
影响因子:
1
通讯作者:
W. M. Khaemba
中科院分区:
文献类型:
--
作者:
W. K. Ottichilo;W. M. Khaemba
Calibration procedures to determine strip widths for use by the Department of Resource Surveys and Remote Sensing (DRSRS) in its aerial surveys are validated by statistical analysis. Tests were made for differences in observer, aircraft and between using photography (camera) and direct observation (naked eye) in the determination of strip widths on the ground. The relationship between strip widths measured on the ground and in the air was determined using regression analysis. Tests were also made for differences between population estimates reported by DRSRS and those recalculated using reported strip widths for elephant, kongoni, wildebeest and cattle. There appears to be no significant differences between observer performance and between reported and recalculated population estimates for all species except cattle. A significant difference was found between strip widths obtained by photography and those through direct observation, with photography values being 14% higher at ground level. Strip widths measured while the aircraft was in the air were highly correlated to those measured while on the ground (r = 0.97). Overall, it can be concluded that the DRSRS standardization of observers, calibration of the aircraft and calculation of population estimates were carried out correctly. Finally, it is recommended that the difference in strip widths determined from photography and through direct observation needs to be considered in the final calculation of population estimates.
Resume
L'analyse statistique valide les procedures de calibrage pour determiner la largeur des bandes a utiliser au Departement de Resource Surveys and Remote Sensing (DRSRS) lors des surveillances aeriennes. On a fait des tests de differences d'observateur, d'avion et entre l'usage de la photographie et les observations directes, a l'œil nu, pour determiner la largeur des bandes au sol. On a utilise une analyse de regression pour determiner la relation entre la largeur des bandes mesurees au sol et en l'air. On a aussi fait des tests de difference entre les estimations de population relevees par le DRSRS et celles qui etaient recalculees a partir des largeurs de bandes relevees pour les elephants, les bubales, les gnous et le betail. Il semble ne pas y avoir de difference significative entre les resultats de l'observateur et les estimations de population relevees et recalculees, pour toutes les especes sauf pour le betail. On a trouve une difference significative entre les largeurs de bandes obtenues par photographie et par observation directe, les valeurs obtenues par photographie etant 14% superieures a celles obtenues au niveau du sol. Les largeurs de bandes obtenues lorsque l'avion etant en vol etaient fortement liees a celles mesurees au sol (r = 0,97). En general, on peut conclure que les standardisations par le DRSRS des observateurs, du calibrage de l'avion et du calcul des estimations de population ont ete correctement menees. Enfin, on recommande de tenir compte de la difference entre les largeurs de bande determinees par photo et par observation directe dans le calcul final des estimations de population.