Argali Abundance in the Afghan Pamir Using Capture–Recapture Modeling From Fecal DNA

Abstract

: Estimating population size in a mark‐recapture framework using DNA obtained from remotely collected genetic samples (e.g., feces) has become common in recent years but rarely has been used for ungulates. Using DNA extracted from fecal pellets, we estimated the size of an argali (Ovis ammon) population that was believed to be isolated from others within the Big Pamir Mountains, Afghanistan, an area where access was difficult and expensive. We used closed‐capture models to estimate abundance, and Pradel models to examine closure assumptions, both as implemented in Program MARK. We also made visual counts of argali in the Big Pamirs, allowing comparison of count indices of abundance with modeled estimates. Our model‐averaged estimate for female argali in the Big Pamir was 172 (95% CI = 117–232), which was about 23% higher than our best assessment using uncorrected visual counts. However, mark‐recapture models suggested that males were not a closed population; thus, we were unable to provide a meaningful estimate of overall population size. Males either suffered much higher mortality than females during the sampling period, or, more likely, males moved in and out of the Big Pamir area. Although information from DNA did not provide a clear overall population estimate, it suggested that the Big Pamir was not isolated from other argali populations, which could not have been confirmed with visual observations alone. Estimating argali population size using mark‐recapture models and fecal DNA is feasible but may be too expensive for frequent monitoring of large and remote populations. Our study demonstrates the importance of sex identification and separate abundance estimation for each sex, especially if movement ecology differs by sex.

Blood meal analysis of tabanid fly after it biting the rare Sumatran rhinoceros

“…Peer reviewer with the advent of polymerase chain reaction (PCR)-based technology [1][2][3][4][5] . This advancement had truly escalated the field of conservation biology particularly when dealing with rare and elusive, endangered, or cryptic fauna [1][2][3][5][6][7][8] .…”

“…This advancement had truly escalated the field of conservation biology particularly when dealing with rare and elusive, endangered, or cryptic fauna [1][2][3][5][6][7][8] .…”

Sampling designs matching species biology produce accurate and affordable abundance indices

“…Many study sites are large (10,000s of km 2 ) and include areas difficult to access, due to vegetation types, terrain, or insecure political situations. Sampling in these areas is logistically difficult or unsafe, and when using small cells sizes, the projects can become prohibitively expensive (Kendall et al, 2009;Harris et al, 2010;Sawaya et al, 2012).…”

“…Wildlife biologists often rely on photographs or DNA in a capture-mark-recapture (CMR) framework to estimate the abundances of sparsely distributed animals inhabiting expansive, heavily vegetated and inaccessible terrain (Karanth & Nichols, 1998;Boulanger et al, 2002;Harris et al, 2010; Kindberg et al, 2011). At issue is how to sample effectively and economically under such conditions.…”

Edge Effect on Density Estimates of a Radiotracked Population of Yellow‐Necked Mice

“…One of them is to ensure a reliable laboratory protocol with careful errorchecking for DNA sample analysis, because genotyping errors like allelic drop-out and false alleles can severely compromise population estimation (Waits & Leberg 2000, Creel et al 2003, Lukacs & Burnham 2005). Another one is that it may be difficult to obtain a sufficiently large sample size and a sufficiently high detection probability with a feasible effort (Ebert et al 2009, Harris et al 2010.…”