Why are caribou declining in the oil sands?

Why are caribou declining in the oil sands? Peer-review ed le tte r Conservation of woodland caribou (Rangifer tarandus caribou; hereafter caribou) is challenging in A lberta’s rapidly developing oil sands region. In the Decem ber issue (Front Ecol Environ 2011; 9 [1 0 ]: 5 4 6 -5 1 ), Wasser et al. made two unexpected claims: (1) caribou conservation is less urgent than previously thought because numbers are stable and well above provincial estimates, and (2) stress caused by hum an activity, and no t wolf (Canis lupus) predation, is the proxim ate cause of caribou decline. W e th ink the conclusions made by Wasser et al. are flawed, thereby obfuscating their m anage­ m ent recom m endations. C aribou popu la tion estim ates obtained by Wasser et al. could be biased (artificially high) because of genotyping error such as th a t caused by allelic dropout, where there is preferential am plification of one of the two alleles at a locus (Schwartz and M onfort 2008). Wasser et al. reported a very high allelic dropout, and even low levels of genotyping error (1-5% ) can cause severe overestim ation of abundance (up to 5.5 times; Creel et al. 2003; McKelvey and Schw artz 2004). A lth o u g h adopting some measures to screen against genotyping errors, Wasser et al. did no t report if they tested for or removed errors, nor did they use captu re-m ark-recapture estimators tha t explicitly incorporate genotyping error (Lukacs and B urnham 2005). Wasser et al. indicated caribou pop­ ulations may no t he in rapid decline because they detected no significant change in caribou population size between 2006 and 2009. Estimating population change over short time intervals is unreliable when confi­ dence limits are as wide as their 2006 estimate. Long-term data collected on caribou vital rates (female sur­ vival and recruitm ent) in the oil sands region suggest drastic declines in the East Side of the A thabasca a I ’ 0 1 ,2