title: Balancing sample accumulation and DNA degradation rates to optimize noninvasive genetic sampling of sympatric carnivores.
abstract: Noninvasive genetic sampling, or noninvasive DNA sampling (NDS), can be an effective monitoring approach for elusive, wide-ranging species at low densities. However, few studies have attempted to maximize sampling efficiency. We present a model for combining sample accumulation and DNA degradation to identify the most efficient (i.e. minimal cost per successful sample) NDS temporal design for capture-recapture analyses. We use scat accumulation and faecal DNA degradation rates for two sympatric carnivores, kit fox (Vulpes macrotis) and coyote (Canis latrans) across two seasons (summer and winter) in Utah, USA, to demonstrate implementation of this approach. We estimated scat accumulation rates by clearing and surveying transects for scats. We evaluated mitochondrial (mtDNA) and nuclear (nDNA) DNA amplification success for faecal DNA samples under natural field conditions for 20 fresh scats/species/season from <1-112 days. Mean accumulation rates were nearly three times greater for coyotes (0.076 scats/km/day) than foxes (0.029 scats/km/day) across seasons. Across species and seasons, mtDNA amplification success was ≥95% through day 21. Fox nDNA amplification success was ≥70% through day 21 across seasons. Coyote nDNA success was ≥70% through day 21 in winter, but declined to <50% by day 7 in summer. We identified a common temporal sampling frame of approximately 14 days that allowed species to be monitored simultaneously, further reducing time, survey effort and costs. Our results suggest that when conducting repeated surveys for capture-recapture analyses, overall cost-efficiency for NDS may be improved with a temporal design that balances field and laboratory costs along with deposition and degradation rates.
authors.affiliation: Department of Fish and Wildlife Sciences, University of Idaho, 875 Perimeter Drive MS1136, Moscow, ID, 83844-1136, USA.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Lonsinger
authors.affiliation: United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Logan, UT, 84322-5230, USA.|Department of Wildland Resources, Utah State University, Logan, UT, 84322-5230, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Gese
authors.affiliation: Department of Wildland Resources, Utah State University, Logan, UT, 84322-5230, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Dempsey
authors.affiliation: Department of Wildland Resources, Utah State University, Logan, UT, 84322-5230, USA.
authors.forename: Bryan M
authors.initials: BM
authors.lastname: Kluever
authors.affiliation: Department of Statistical Science, University of Idaho, 875 Perimeter Drive MS1104, Moscow, ID, 83844-1104, USA.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Johnson
authors.affiliation: Department of Fish and Wildlife Sciences, University of Idaho, 875 Perimeter Drive MS1136, Moscow, ID, 83844-1136, USA.
authors.forename: Lisette P
authors.initials: LP
authors.lastname: Waits
mesh_terms: D000818:Animals; D002335:Carnivora / Q000145:classification* / Q000235:genetics*; D003362:Cost-Benefit Analysis; D004247:DNA / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000737:chemistry*; D012621:Seasons; D013048:Specimen Handling / Q000191:economics / Q000379:methods*; D014589:Utah
chemical_list: D004247:DNA
keywords: Canis latrans; DNA degradation; Vulpes macrotis; genotyping error; noninvasive genetic sampling; scat deposition