The tule elk (Cervus canadensis nannodes) is a California endemic subspecies that experienced an extreme bottleneck (potentially two individuals) in the mid-1800s. Through active management, including reintroductions, the subspecies has grown to approximately 6000 individuals spread across 22 recognized populations. The populations tend to be localized and separated by unoccupied intervening habitat, prompting targeted translocations to ensure gene flow. However, little is known about the genetic status or connectivity among adjacent populations in the absence of active translocations. We used 19 microsatellites and a sex marker to obtain baseline data on the genetic effective population sizes and functional genetic connectivity of four of these populations, three of which were established since the 1980s and one of which was established ~ 100 years ago. A Bayesian assignment approach suggested the presence of 5 discrete genetic clusters, which corresponded to the four primary populations and two subpopulations within the oldest of them. Effective population sizes ranged from 15 (95% CI 10–22) to 51 (95% CI 32–88). We detected little or no evidence of gene flow among most populations. Exceptions were a signature of unidirectional gene flow to one population founded by emigrants of the other 30 years earlier, and bidirectional gene flow between subpopulations within the oldest population. We propose that social cohesion more than landscape characteristics explained population structure, which developed over many generations corresponding to population expansion. Whether or which populations can grow and reach sufficient effective population sizes on their own or require translocations to maintain genetic diversity and population growth is unclear. In the future, we recommend pairing genetic with demographic monitoring of these and other reintroduced elk populations, including targeted monitoring following translocations to evaluate their effects and necessity.

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Spatially explicit capture-recapture (SCR) approaches using noninvasive fecal DNA (fDNA) are applied increasingly to obtain statistically robust abundance estimates for various wildlife species. But SCR has not been widely used for more gregarious species, such as elk (Cervus canadensis). Because of their heterogeneous use of the landscape and grouping behavior, elk present novel challenges to sampling efficiency and statistical assumptions. We employed fDNA SCR and a stratified random sampling approach to estimate abundance in 3 northern California tule elk (C. c. nannodes) populations concurrent with global positioning system (GPS)-telemetry monitoring of 66 elk (32 male, 34 female) in Colusa and Lake counties, California, USA, during June-August 2017-2019. We collected 1,616 fecal pellet groups from the 3 populations, resulting in 1,002 fDNA genotypes (≥19 microsatellite loci, 1 sex marker) of 425 unique individuals. Based on SCR estimates from a model incorporating both sexes, elk density ranged from 0.31 (95% CI = 0.17-0.55) elk/km 2 to 1.7 (95% CI = 1.3-2.2) elk/km 2 , translating approximately to 650 individuals (evenly split between sexes) among the 3 populations. Independent telemetry data from concurrently tracked individuals indicated that activity centers of females, but not males, were clustered on the landscape. This finding was corroborated using fDNA to infer activity centers. Comparison of SCR estimates to non-spatial estimates using physically captured individuals suggested that combined-sex SCR models were robust to spatial clustering of females in all 3 populations.

The statewide management plan discusses methods of assessing population viability. The Department is committed to funding and staffing actions to achieve the goals of the EMU plans. The Department recognizes that some of its proposed activities and species management plans may adversely affect the interests of California Tribes. The Department is committed to consulting with Tribes on fish, wildlife and plant issues, and assessing and avoiding to the extent possible adverse impacts of Department activities on tribal interests. The Department and Tribes share authority to regulate the take of elk as they move across the landscape and jurisdictional boundaries. The Department possesses regulatory authority within state boundaries and Tribes possess regulatory authority within tribal land. A Tribe maintains inherent power to regulate the take of elk by its members within its reservation. (New Mexico v. Mescalero Apache Tribe (1983) 462 U. S. 324, 332, 335). Application of the FGC to a Tribe and its members within that Tribe's reservation is limited (FGC §12300).The Department may not enforce its elk regulations against tribal members within their Tribe's reservation when doing so is preempted by federal law or would infringe on the right of self-government.Moreover, the Department is committed to providing meaningful opportunities to participate in decision-making processes that affect tribal interests.

Historically, aerial surveys have been used widely to monitor abundance of large mammals in the western United States. In California, such surveys have typically served as minimum count indices rather than true abundance estimates. Here, we evaluated the utility of aerial multiple covariate distance sampling (MCDS) to estimate abundance of three populations of tule elk (Cervus canadensis nannodes) in northern California. We also compared estimates and costs with published results from a concurrent fecal DNA spatial capture-recapture (SCR) survey. During December 2018 and 2019, we flew line transects for distance sampling of tule elk in Colusa and Lake counties. We modeled detection functions and evaluated effects of group size, canopy cover, and survey year. We averaged the top models comprising ≥0.95 of Akaike Model Weight and estimated abundance of both total and discrete populations. Detection probability increased with increasing group size and decreasing canopy cover. We estimated a two-year average total population size of N̂ = 674 elk (90% CI = 501–907) in our survey area which was similar to N̂ = 653 elk (90% CI = 573–745) from SCR estimates. Overall precision was greater (CV = 0.08; range = 0.11–0.30 by population) for SCR than for MCDS (CV = 0.18; range = 0.22–0.43 by population). Although estimates differed somewhat between methods for the individual populations, the combined estimate across the study region compared favorably. Total cost of SCR and MCDS surveys was $98,326 and $147,324, respectively. While SCR efforts were more precise and less expensive overall, our MCDS approach reduced staff time by 64% (587 person-hours) and the number of survey days by 87% (64 days). Our results suggest MCDS methods can produce reliable abundance estimates across a gradient of canopy cover, particularly when observations can be pooled across populations to decrease variance. We recommend future research to assess use of hybrid models, such as mark-recapture distance sampling or hierarchical distance sampling, to improve precision and estimation of detection probability.