This could contribute to hybridization with coyotes to avoid MHC-similar mates. I found little evidence for pedigree kinship avoidance but red wolves may avoid mates with more similar MHC alleles. Finally, I evaluated red wolves’ mate choice (Chapter 6). There were also several TLR haplotypes which were correlated with disease susceptibility. Red wolves had lower immune gene variation then coyotes variation may have been maintained through positive selection at MHC genes (Chapter 5). Coyotes harbored more parasite species then wolves and may act as disease reservoirs for red wolves (Chapter 4). Next, I evaluated how immunogenetic variation influenced disease susceptibility by collecting baseline disease prevalence in red wolves and sympatric coyotes (Canis latrans), and sequencing MHC and toll-like receptor (TLR) genes. However, more inbred wolves tended to be smaller, which may have an indirect effect on reproductive success (Chapter 3). With regard to inbreeding depression, I found that red wolves were extremely inbred but their fitness was not associated with inbreeding. Although these analyses were not directly related to inbreeding, clarifying red wolf taxonomic status is vital for effective species conservation. I found evidence for an ancient red wolf origin which supports contemporary red wolf management practices (Chapter 2). I also evaluated mitochondrial DNA from ancient canid bones to inform an ongoing debate regarding the species status of red wolves. My dissertation research examined how inbreeding and immunogenetic variation influenced fitness, disease susceptibility, and mating behavior in endangered wild red wolves (Canis rufus). Given broad impacts of inbreeding and MHC variation on fitness and behavior, evaluating their effects is an important component of wildlife management. Mate choice may also be facilitated by variation at major histocompatibility complex (MHC) genes, a gene group critical for immune response and disease resistance. The negative effects of inbreeding results in the evolution of inbreeding avoidance behaviors within small populations, such behaviors may encourage individuals to select mates outside of their respective species. More broadly, we discuss the lessons learned from red wolf adaptive management that could assist other endangered species recovery efforts facing the challenge of minimizing hybridization.Inbreeding depression, the reduction in offspring fitness caused by mating among close relatives, is widespread in small populations and a major concern in conservation biology because it can affect population persistence. We conclude that the adaptive management plan was effective at reducing the introgression of coyote genes into the red wolf population, but population recovery of red wolves will require continuation of the current management plan, or alternative approaches, for the foreseeable future. The genetic composition of the wild red wolf population is estimated to include < 4% coyote ancestry from recent introgression since reintroduction. We documented substantial increases in the number of known red wolves and red wolf social groups from 1987–2004 followed by a plateau and slight decline by 2013.The number of red wolf litters exceeded hybrid litters each year and the proportion of hybrid litters per year averaged 21%. Here we review the application and results of the adaptive management efforts from 1993 to 2013 by comparing: (1) the numbers of wolves, coyotes, and hybrids captured, (2) the numbers of territorial social groups with presumed breeding capabilities, (3) the number of red wolf and hybrid litters documented each year and (4) the degree of coyote introgression into the wild red wolf gene pool. By 1999, managers recognized hybridization with invasive coyotes Canis latrans was the single greatest threat to successful recovery, and an adaptive management plan was adopted with innovative approaches for managing the threat of hybridization. From 1987?1993, 63 red wolves were released from captivity in eastern North Carolina, USA, to establish a free-ranging, non-essential experimental population. Fish and Wildlife Service (USFWS) removed the last remaining red wolves from the wild and placed them in a captive-breeding program. The endangered species recovery effort for the red wolf Canis rufus is a classic system for understanding and addressing the challenges of hybridization. While hybridization is an important evolutionary process, hybridization is also a threat formany native species. Hybridization presents a unique challenge for conservation biologists and managers.
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