Mexican Wolf Research Articles

APPLYING CLINICALLY PROVEN HUMAN TECHNIQUES FOR CONTRACEPTION AND FERTILITY TO ENDANGERED SPECIES AND ZOO ANIMALS: A REVIEW

Reversible contraception that does not alter natural behavior is a critical need for managing zoo populations. In addition to reversible contraception, other fertility techniques perfected in humans may be useful, such as in vitro fertilization (IVF) or oocyte and embryo banking for endangered species like amphibians and Mexican wolves (Canis lupus baileyi). Furthermore, the genetics of human fertility can give a better understanding of fertility in more exotic species. Collaborations were established to apply human fertility techniques to the captive population. Reversible vasectomy might be one solution for reversible contraception that does not alter behavior. Reversible approaches to vasectomy, avoiding secondary epididymal disruption, were attempted in South American bush dogs (Speothos venaticus), chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla), Przewalski's horse (Equus przewalski poliakov), and Sika deer (Cervus nippon) in a variety of zoos around the world. These techniques were first perfected in > 4,000 humans before attempting them in zoo animals. In vitro fertilization with gestational surrogacy was used to attempt to break the vicious cycle of hand rearing of purebred orangutans, and egg and ovary vitrification in humans have led to successful gamete banking for Mexican wolves and disappearing amphibians. The study of the human Y chromosome has even explained a mechanism of extinction related to global climate change. The best results with vasectomy reversal (normal sperm counts, pregnancy, and live offspring) were obtained when the original vasectomy was performed "open-ended," so as to avoid pressure-induced epididymal disruption. The attempt at gestational surrogacy for orangutans failed because of severe male infertility and the lack of success with human ovarian hyperstimulation protocols. Vitrification of oocytes is already being employed for the Amphibian Ark Project and for Mexican wolves. Vasectomy can be a reversible contraception option in zoo animals, even in endangered species. Ongoing use of gamete and embryo freezing may salvage vanishing species.

Developing Metapopulation Connectivity Criteria from Genetic and Habitat Data to Recover the Endangered Mexican Wolf

Restoring connectivity between fragmented populations is an important tool for alleviating genetic threats to endangered species. Yet recovery plans typically lack quantitative criteria for ensuring such population connectivity. We demonstrate how models that integrate habitat, genetic, and demographic data can be used to develop connectivity criteria for the endangered Mexican wolf (Canis lupus baileyi), which is currently being restored to the wild from a captive population descended from 7 founders. We used population viability analysis that incorporated pedigree data to evaluate the relation between connectivity and persistence for a restored Mexican wolf metapopulation of 3 populations of equal size. Decreasing dispersal rates greatly increased extinction risk for small populations (<150-200), especially as dispersal rates dropped below 0.5 genetically effective migrants per generation. We compared observed migration rates in the Northern Rocky Mountains (NRM) wolf metapopulation to 2 habitat-based effective distance metrics, least-cost and resistance distance. We then used effective distance between potential primary core populations in a restored Mexican wolf metapopulation to evaluate potential dispersal rates. Although potential connectivity was lower in the Mexican wolf versus the NRM wolf metapopulation, a connectivity rate of >0.5 genetically effective migrants per generation may be achievable via natural dispersal under current landscape conditions. When sufficient data are available, these methods allow planners to move beyond general aspirational connectivity goals or rules of thumb to develop objective and measurable connectivity criteria that more effectively support species recovery. The shift from simple connectivity rules of thumb to species-specific analyses parallels the previous shift from general minimum-viable-population thresholds to detailed viability modeling in endangered species recovery planning.

Resistance and Common Ground as Functions of Mis/aligned Attitudes

Writing scholars interested in stakeholder attitudes need ways to reconstruct them from archives because (a) interview/survey studies are not always feasible (particularly in historical work) and (b) the question/answer format of these studies may exclude key attitudes that emerge in unprompted expressions of opinion. Accordingly, this article argues for filter theory—a pragmatic model of interpretive attitudes—as an effective hermeneutic for archival reception studies. Complementing a previous study of administrative attitudes about the Mexican Wolf Blue Range Reintroduction Project, the present study applies filter theory to a sample of ranchers’ written opinions about the Project. The main findings are as follows: Ranchers and administrators differentially value resident rights versus Project goals; ranchers warrant resistance to the Project based on these misaligned attitudes; nonetheless, both groups value the ideal of a balanced environment and evidence collected on the ground. These findings suggest the need to redefine rhetorical resistance and common ground as arguments warranted by mis/alignments between groups’ interpretive attitudes. They also indicate revisions to initial recommendations for extending rhetorical common ground in the Project.

Socioecological systems along the US/Mexico border

Socioecological systems along the US/Mexico border

Anthropogenic impacts to the recovery of the Mexican gray wolf with a focus on trapping-related incidents

Concerns regarding the potential negative impacts of regulated furbearer trapping to reintroduced Mexican gray wolves (Canis lupus baileyi), led to an executive order prohibiting trapping in the New Mexico, USA, portion of the Blue Range Wolf Recovery Area. This ban was to last for 6 months and required an evaluation of the risk posed to wolves by traps and snares legally permitted in New Mexico. We reviewed potential threats to wolves in the Blue Range Wolf Recovery Area, including threats associated with regulated furbearer trapping. One hundred Mexican gray wolf mortalities have been documented during the reintroduction effort (1998–2011). Of those mortalities with a known cause, >81% were human-caused resulting from illegal shooting (n = 43), vehicle collisions (n = 14), lethal removal by the United States Fish and Wildlife Service (USFWS; n = 12), non-project-related trapping (n = 2), project-related trapping (n = 1), and legal shooting by the public (n = 1). Ten wolves died due to unknown causes. The remaining 17 mortalities were a result of natural causes (e.g., starvation, disease). An additional 23 wolves were permanently, but non-lethally, removed from the wild by the USFWS. Of 13 trapping incidents in New Mexico that involved non-project trappers (i.e., trappers not associated with USFWS or U.S. Department of Agriculture-Wildlife Services), 7 incidents are known to have resulted in injuries to wolves: 2 wolves sustained injuries severe enough to result in leg amputations and 2 additional wolves died as a result of injuries sustained. Foothold traps with rubber-padded jaws and properly set snares may reduce trap-related injuries to Mexican gray wolves; however, impacts caused by trapping are overshadowed by other anthropogenic impacts (e.g., illegal shooting, non-lethal permanent removal, and vehicle collisions). © 2013 The Wildlife Society.

Intestinal Rupture in a Mexican Gray Wolf (Canis lupus baileyi) in Association with Ingestion of a Diazinon-Impregnated Cattle Ear Tag

A free-ranging Mexican gray wolf (Canis lupus baileyi) suffered intestinal rupture following ingestion of an insecticidal cattle ear tag. Subsequent organophosphate toxicosis as a cause of the rupture was speculated. Insecticidal ear tags could represent a poisoning risk in canids and other wildlife scavengers.

An Account of the Taxonomy of North American Wolves From Morphological and Genetic Analyses

AbstractThe available scientific literature was reviewed to assess the taxonomic standing of North American wolves, including subspecies of the gray wolf, Canis lupus. The recent scientific proposal that the eastern wolf, C. l. lycaon, is not a subspecies of gray wolf, but a full species, Canis lycaon, is well-supported by both morphological and genetic data. This species' range extends westward to Minnesota, and it hybridizes with gray wolves where the two species are in contact in eastern Canada and the Upper Peninsula of Michigan, Wisconsin, and Minnesota. Genetic data support a close relationship between eastern wolf and red wolf Canis rufus, but do not support the proposal that they are the same species; it is more likely that they evolved independently from different lineages of a common ancestor with coyotes. The genetic distinctiveness of the Mexican wolf Canis lupus baileyi supports its recognition as a subspecies. The available genetic and morphometric data do not provide clear support for the recognition of the Arctic wolf Canis lupus arctos, but the available genetic data are almost entirely limited to one group of genetic markers (microsatellite DNA) and are not definitive on this question. Recognition of the northern timber wolf Canis lupus occidentalis and the plains wolf Canis lupus nubilus as subspecies is supported by morphological data and extensive studies of microsatellite DNA variation where both subspecies are in contact in Canada. The wolves of coastal areas in southeastern Alaska and British Columbia should be assigned to C. lupus nubilus. There is scientific support for the taxa recognized here, but delineation of exact geographic boundaries presents challenges. Rather than sharp boundaries between taxa, boundaries should generally be thought of as intergrade zones of variable width.

Conservation genomics of the Mexican Wolf

Conservation genomics of the Mexican Wolf

Consensus on Criteria for Potential Areas for Wolf Reintroduction in Mexico

Given the conflict with human interests that in many cases results in the extirpation of large carnivores, acceptance of their reintroduction is a considerable challenge. By the 1980s Mexican wolves (Canis lupus) were extinct in the wild. In 1998 a population was reintroduced in the Blue Range Mountains of New Mexico (U.S.A.). Efforts to reintroduce the species in Mexico have been ongoing since the late 1980s. Four teams working independently identified 6 areas in northern Mexico in the historic range of Mexican wolves, where reintroductions could potentially be successful. Each team used different methods and criteria to identify the areas, which makes it difficult to prioritize among these areas. Therefore, members of the different teams worked together to devise criteria for use in identifying priority areas. They identified areas with high, intermediate, and low potential levels of conflict between wolves and humans. Areas with low potential conflict had larger buffers (i.e., distance from human settlement to areas suitable for wolves) around human settlements than high- and intermediate-conflict areas and thus were thought most appropriate for the first reintroduction. High-conflict areas contained habitat associated with wolf presence, but were closer to human activity. The first reintroduction of Mexican wolves to Mexico occurred in October 2011 in one of the identified low-conflict areas. The identification of suitable areas for reintroduction represents a crucial step in the process toward the restoration of large carnivores. Choice of the first reintroduction area can determine whether the reintroduction is successful or fails. A failure may preclude future reintroduction efforts in a region or country.

The effect of zoo visitors on the behaviour and faecal cortisol of the Mexican wolf ( Canis lupus baileyi)

The effect of zoo visitors on the behaviour and physiological responses of the Mexican wolf has not been documented but is worthy of investigation since it is a critically endangered native species and most of the population live in zoos. The effect of the number of visitors was assessed in 12 wolves (five males and seven females) in three zoos of central Mexico. Each wolf was observed for a total of 72 h on Saturdays, Sundays, Mondays and Tuesdays (6 h/day) during a three-week period. Scan sampling was used to obtain individual time budgets. A faecal sample was collected on the following morning of each observation day from 10 wolves to determine cortisol level (RIA). A repeated measures analysis of variance revealed that there was an effect of day on the proportion of time lying ( P < 0.01), eating ( P < 0.01) and in locomotion ( P < 0.01). Wolves spent less time lying on Saturdays and Sundays (0.2980 ± 0.012 and 0.3266 ± 0.012, respectively) than on Mondays and Tuesdays (0.3821 ± 0.012 and 0.4075 ± 0.012, respectively), as well as less time eating on weekend days (Saturdays 0.1214 ± 0.015, Sundays 0.0556 ± 0.015) than in the other 2 days (Mondays 0.816 ± 0.015 and Tuesdays 0.0915 ± 0.015). Mean faecal cortisol was 203.7 ng/g of DM and ranged from 113.10 to 314.48 ng/g. There was an effect of day on the faecal cortisol response ( P < 0.01) with wolves having higher cortisol response on Sundays (242.50 ng/g ± 8.48) compared to the other 3 days (Saturdays 192.71 ± 8.48, Mondays 170.73 ng/g ± 7.80, Tuesdays 183.82 ng/g ± 8.48). This is the first study that measures faecal cortisol of Mexican wolves. These results indicate that the amount of visitors in zoos influence the behaviour and adrenal activity of these animals which could be undesirable for ex situ conservation efforts of this endangered species.

Statistical precision of diet diversity from scat and pellet analysis

Knowledge of trophic interactions is of vital importance for understanding ecological community dynamics. While techniques such as direct observation of prey consumption and stomach content analysis are suitable for some species; for wide ranging carnivores, especially those of conservation concern, analysis of matter in faecal scats or regurgitated pellets is still common practice. This study investigates sample sizes needed to predict changes in the diversity of the diet of three carnivore species (grey seals, Mexican wolves and long horned owls). Using a bootstrapping process, estimations of precision of diet diversity (i.e. the number and evenness of prey species, as measured using Simpson's index) were made with increasing sample sizes (numbers of scats/pellets sampled). Precision of diversity of diet was much greater for grey seals than for owls or wolves, largely because the number of prey items (remains of individuals of the same or different species) in a scat was much higher. When these results are used to test hypotheses to determine difference in diet diversity, the results show that changes in seal diet diversity between different areas of the North Sea could be elucidated with analysis of as few as three scats from each region. However, demonstrating differences in diet diversity between different, but related, owl species from the same area would not be possible even if the contents of >>500 pellets were analysed. This study provides tools and guidelines for sample size requirements in scat or pellet analysis for future studies, as well as indicating that in some cases – for example in grey seals – scat samples may be an efficient method of investigating changes in diet diversity, and hence niche breath, which may alter with prey availability as caused by anthropogenic pressures such as climate change and fishing.

Effect of semen collection method on sperm motility of gray wolves (Canis lupus) and domestic dogs (C. l. familiaris)

Genetic management of Mexican gray wolves includes semen banking, but due to the small number of animals in the population and handling restrictions, improvements in semen collection and cryopreservation rely on results from studies of domestic dogs. Semen collection from wolves requires anesthesia and electroejaculation, which introduce potentially important variables into species comparisons, as dog semen is typically collected manually from conscious animals. To investigate possible effects of collection method on semen quality, we compared semen collection by the traditional manual method and by electroejaculation (EE) in a group of dogs (n = 5) to collection by EE only in wolves (n = 7). Samples were divided into two aliquots: neat or diluted in Tris/egg yolk extender, with motility evaluated at intervals up to 24 h. There were no differences (P > 0.10) in sperm motility in either neat or extended samples at 24 h from EE dogs and wolves, although motility of the wolf neat samples declined more rapidly (P < 0.05). However, there were differences (P < 0.01) between EE and manually collected dog semen in motility at 24 h, in both the neat and extended samples. Therefore, general motility patterns of dog and wolf semen collected by EE were similar, especially when diluted with a Tris/egg yolk extender, but sperm collected from dogs by EE did not maintain motility as long as manually collected samples, perhaps related to the longer exposure of EE samples to more prostate fluid.

Domestic calf mortality and producer detection rates in the Mexican wolf recovery area: Implications for livestock management and carnivore compensation schemes

Conserving large carnivores throughout the world will often require that they share the landscape with livestock. Minimizing depredations and increasing tolerance by livestock producers will be critical for conservation efforts. To investigate factors influencing calf mortality and producer detection rates (i.e., number of livestock killed by predators, found by producers, and correctly classified as to cause of death), we monitored radio-tagged domestic calves at two sites in the Mexican wolf recovery area (East Eagle [EE] and Adobe Ranch [AR]). Study areas differed in grazing practices, density of predators (mountain lions, black bears, coyotes, and Mexican wolves), and amount of effort spent monitoring cattle. We radiotagged 618 calves over 3.5years, and 312 calves over 2years on the EE and AR, respectively. The overall proportion of radioed calves that died was higher on the EE (6.5%) than on the AR (1.9%). Predators (especially mountain lions) accounted for 85% of mortality on the EE and 0% on the AR. Calves selected by predators were on average 25days younger than the surviving cohort. Our results indicate that year-round calving, especially in areas with high predator densities, are subject to higher losses primarily because calves are exposed to mortality agents for longer periods of time rather than having higher natural rates of mortality. We found a significant difference in producer detection rates between study sites, likely due to differences in the intensity of monitoring cattle between sites. On the EE, the producer detected 77.5% of mortalities and on the AR, the producer detected 33% of mortalities. Our results support changing husbandry practices to limit calving to a seasonal endeavor and that performance payment may be a better compensation strategy than ex post compensation schemes.

The Contribution of the Captive Breeding in Mexican Grey Wolf (&lt;i&gt;Canis lupus baileyi&lt;/i&gt;) and Red Wolf (&lt;i&gt;Canis rufus&lt;/i&gt;)

The availability of captive breeding makes a big contribution to wildlife conservation. The zoos become a useful and scientific place for animal protection and conservation research. Moreover, some technologies, such as noninvasive endocrine monitoring, artificial insemination (AI) and semen cryopreservation are widely implemented during the captive breeding. Reintroduction programs have been established with effective managements and monitoring to ensure the wildlife survival rate, genetic purity and original biological traits. The Mexican grey wolf ( Canis lupus baileyi ) and Red Wolf ( Canis rufus ) are two successful examples of captive breeding in order to keep genetic diversity. This article has summarized these technologies which play an important role in Mexican grey wolf ( Canis lupus baileyi ) and Red Wolf ( Canis rufus ) conservation and may be influential in other species captive breeding.

Genetics and wolf conservation in the American West: lessons and challenges

Top predators are endangered throughout the world because of human persecution and habitat destruction. Plans to conserve and restore predator populations are often contentious, but few species are as problematic as the gray wolf (Canis lupus). In the United States, wolf conservation policy and management has often been schizophrenic, ranging from predator control and open hunting to reintroduction and absolute protection. Likewise, public and scientific opinion is equally divided between those who maintain that wolves are an essential part of ecosystems and provide top-down effects contrasting with those who believe wolves cannot readily coexist with humans, especially in landscapes dominated by ranching or farming. In the American West, there have been large-scale reintroductions of the gray wolf (C. lupus nubilus) in the Northern Rocky Mountains (NRMs) and the Mexican wolf (C. lupus baileyi) in the southwest, which provide important lessons for reintroduction efforts elsewhere. In this study, we specifically discuss wolf conservation in the American West in relation to critical genetic factors that affect restoration, recovery and conservation. We also discuss the natural colonization of wolves in Sweden and Norway, and discuss a synthesis of problems and solutions in the large-scale recovery of wolves.

Vitrification of oocytes from endangered Mexican gray wolves ( Canis lupus baileyi)

Careful genetic management, including cryopreservation of genetic material, is central to conservation of the endangered Mexican gray wolf. We tested a technique, previously used to vitrify human and domestic animal oocytes, on oocytes from domestic dogs as a model and from the endangered Mexican wolf. This method provided a way to conserve oocytes from genetically valuable older female Mexican wolves as an alternative to embryos for preserving female genes. Oocytes were aspirated from ovaries of 36 female dogs in December and March (0 to 65 oocytes per female) and from six female wolves (4 to 73 per female) during their physiologic breeding season, or following stimulation with the GnRH agonist deslorelin. Oocytes from dogs were pooled; half were immediately tested for viability and the remainder vitrified, then warmed and tested for viability. All oocytes were vitrified by being moved through media of increasing cryoprotectant concentration, placed on Cryotops, and plunged into liquid nitrogen. There was no difference in viability (propidium iodide staining) between fresh and vitrified, warmed dog oocytes (65.7 and 61.0%, respectively, P = 0.27). Oocyte viability after warming was similarly assessed in a subset of wolves (4 to 15 oocytes from each of three females; total 29 oocytes). Of these, 57.1% of the post-thaw intact oocytes were viable, which was 41.4% of all oocytes warmed. These were the first oocytes from a canid or an endangered species demonstrated to have maintained viability after vitrification and warming. Furthermore, our results demonstrated that vitrification of oocytes with the Cryotop technique was an option for preserving female gametes from Mexican wolves for future use in captive breeding programs, although in vitro embryo production techniques must first be developed in canids for this technique to be used.

Mexican wolves, elk, and aspen in Arizona: Is there a trophic cascade?

In 1998, Mexican gray wolves ( Canis lupus baileyi) were introduced into the Blue Range Wolf Recovery Area (BRWRA) that spans adjacent portions of Arizona and New Mexico. In 2009 we selected three mixed-conifer sites on the Apache National Forest, within the BRWRA of east-central Arizona, to characterize long-term age structure of aspen ( Populus tremuloides) and to check for the possible occurrence of a tri-trophic cascade involving Mexican wolves, Rocky Mountain elk ( Cervus elaphus nelsoni), and aspen. These mixed-conifer sites included (a) a refugium site, (b) an old-growth site, and (c) a site thinned in 1991–1992. The refugium site was inaccessible to elk and cattle whereas the old-growth and thinned sites were accessible to elk, but not cattle. Age structure results indicated that aspen recruitment (i.e., the growth of sprouts/seedlings into tall saplings, poles, and eventually trees) at the refugium site had been ongoing over a period of many decades. In contrast, aspen recruitment at the old-growth and thinned sites decreased significantly ( p < 0.05) during the two most recent decades when elk populations, as indexed by annual harvest levels, were relatively “high”. From 2000 to 2008, only 2.9 Mexican wolves per 1000 elk were present on the Apache National Forest compared to 9.3 western gray wolves ( Canis lupus occidentalis) per 1000 elk in Yellowstone National Park where tri-trophic cascades involving wolves, elk, and aspen have been reported. The low number of Mexican wolves relative to their primary prey (elk) suggests that an ecologically effective density of wolves has not become established in east-central Arizona. Furthermore, the lack of recent aspen recruitment in stands accessible to elk indicates an absence, to date, of a tri-trophic cascade.

Integration of Two Newly Formed Couples of Canis lupus baileyi at Two Zoos in Mexico

Integration of Two Newly Formed Couples of Canis lupus baileyi at Two Zoos in Mexico

The importance of reproductive management and monitoring in canid husbandry and endangered‐species recovery

The importance of captive breeding has evolved as zoos themselves have evolved. Beyond allowing captive populations to be self‐sustaining, zoos can contribute to species recovery and reintroduction by improving reproductive rates and developing monitoring techniques that provide data critical to understanding reproductive processes. Several threatened canid species have recently been saved through captive‐breeding efforts in partnership with reintroduction programmes. Two of those, the Mexican grey wolf Canis lupus baileyi and the Island fox Urocyon littoralis, provide case studies. For both species, data generated during monitoring revealed important basic features of their biology and also provided critical information to managers that could be used to enhance reproductive rates. Both species are also part of reintroduction programmes that exemplify successful partnerships between the United States Fish and Wildlife Service and North American zoos.

Reproductive management in captive and wild canids: contraception challenges

Managing reproduction for Canidae species is a challenge for zoological institutions and wildlife sanctuaries. There are four basic options for contraception: separation of sexes, surgical procedures, immunological and hormonal methods. Animal managers face potential challenges for each option, and advantages and disadvantages should be taken into consideration when making a decision. This paper evaluates four common Canidae species with results from hormonal monitoring: Gray wolves Canis lupus/Mexican gray wolves Canis lupus baileyi, Maned wolves Chrysocyon brachyurus, Fennec fox Vulpes zerda and African wild dogs Lycaon pictus. Special focus is given to individuals treated with the gonadotropin‐releasing hormone (GnRH) agonist, Suprelorin®. To date there are considerably more data for African wild dogs than other canids, as extensive field observations are available for this species. Therefore, African wild dogs are more extensively covered in this paper. GnRH agonists have been designated the safest reversible method of contraception for carnivores and so continued studies are important. Results outlined below demonstrate individual dosing differences that occur not only across species but also between similar individuals. Although dosing and duration of efficacy still need further investigating, GnRH agonists are still considered to be the safest and most appropriate method available. As evident in this paper, contraception is a much‐needed tool for reproductive management.