Year of Publication
Arts and Sciences
Bachelors of Science
AS HUMANITY continues to grow and expand, we inevitably encroach on wildlife habitat. This can create conflict between humans and wildlife. Human wildlife conflict usually occurs when humans are near areas where wildlife typically reside. A prime example is a farmer coming into conflict with animals that predate their seeds or livestock. The most common response to this problem in many areas is lethal control to prevent economic loss (Dickman 2010). This seems like an immediate resolution of the conflict in the human’s perspective, but this action can have many adverse effects. This killing may result in negative social outcry, as well as harmful ecosystem effects if poisons are used (Massei et al. 2010). Another way to reduce this conflict while reducing these adverse effects is through translocation. Translocation is the movement of animals from one area to another by humans (Massei et al. 2010; IUCN 2013). Specifically, mitigation translocation is the movement of animals from their environment due to the continuous encroachment of humans through development projects, newly built neighborhoods, or other anthropocentric reasons (IUCN 2013; Germano et al. 2015). Mitigation translocations have become more common as humans proceed to expand into natural land (Nowak et al. 2002; IUCN 2013; Germano et al. 2015). Translocation is also used for other reasons, including the conservation of threatened species or declining populations (IUCN 2013).
Translocations have been used across many taxa. They are widely used to reduce human conflict with large mammals such as grizzly bears (Ursus arctos), cheetahs (Acinonyx jubatus), and leopards (Panthera pardus fusca) usually having little success. Translocated animals experienced higher mortality, higher stress, or homing behaviors that led to more conflict with humans (Athreya et al. 2011; Boast et al. 2016; Milligan et al. 2018). Translocation has been used in conservation practice to supplement declining populations in red-cockaded woodpeckers (Picoides borealis) with some success. Translocated birds were found in potential breeding groups and were found to contribute to the overall population after one year (Herbez et al. 2011). They have even been used in many species of insects and freshwater fish as they face problems such as climate change and invasive species (Cochran-Biederman et al. 2015; Bellis et al. 2019). Reptiles are used in translocations for both conservation and mitigation of human conflict. However, reviews on translocation of herpetofauna show success rates are low and the results of most translocations are unable to be determined due to the lack of scientific data surrounding them (Dodd and Seigel 1991; Germano and Bishop 2009).
However, there are many problems with the practice of translocation. Many translocation events occur without monitoring the animals before or after translocation. Consequently, the success of these projects is unknown without data to prove the translocation was beneficial to both the animals and humans involved (Dodd and Seigel 1991; Germano et al. 2015; Sullivan et al. 2015). While more scientific data on translocations will be helpful to understand how human wildlife conflict is changed, it will also help to improve future mitigation and conservation-based translocations. (IUCN 2013; Milligan et al. 2018).
Snakes are often the subject of mitigation translocations as they are feared and seen as dangerous. Rattlesnakes are especially a target group among reptiles as they pose a potential risk to humans with their venomous bite. Although the mortality from venomous snakes is only estimated at 5-7 deaths a year in North America, the estimated envenomations per year can climb close to 4,000 (Kasturiratne et al. 2008). Translocations may be a better solution than killing snakes as they can be helpful in reducing both deaths and envenomations, while reducing negative ecological effects (Corbit and Hayes 2022). Translocation methods are quite variable in snakes. Studies differ in the distance they are translocated and are usually classified as short or long-distance translocation (SDT or LDT). They also differ in the different types of groups being used, while some studies compare the same snakes before and after translocation, others compare two different groups of snakes one translocated and one not translocated (Reinert and Rupert 1999; Kelley et al. 2022). While translocation is seen as a preferred method of relieving conflict without killing, there have been many studies that find translocations of venomous snakes to be highly disruptive and sometimes lethal to the animals involved. In a translocation study involving the Timber Rattlesnake (Crotalus horridus), translocated snakes experienced home ranges up to 10 times larger, daily movements 3 times longer, and significantly higher mortality rates as compared to resident snakes (Reinert and Rupert 1999). Many other translocation studies have found similar results using Crotalus atrox, Vipera berus, Pseudonaja affinis, and Crotalus adamanteus (Nowak et al. 2002; Nash et al. 2018; Wolfe et al. 2018; Kelley et al. 2022).
The Eastern Black-Tailed Rattlesnake (Crotalus ornatus) is a medium sized, venomous species of rattlesnake found in the northern Chihuahuan desert (Emerson et al. 2022). Little is known about the effects of translocation on C. ornatus. Most information is based on the name of its former conspecific, the Northern Black-Tailed Rattlesnake (Crotalus molossus) which were found to be distinct in 2012. (Anderson and Greenbaum 2012; Emerson et al. 2022).
This study assesses the effects of translocation on the spatial and thermal ecology of C. ornatus. We compared 3 male translocated C. ornatus with 3 resident C. ornatus over a 4-month period in the active season. Snakes were located with radio transmitters and internal body temperatures were taken with WeePits. Past studies led us to hypothesize that translocated snakes would have larger home ranges, poorer body conditions, and reduced survival rates as compared to resident snakes. This study is the first known on translocation in C. ornatus and one of few studying spatial ecology in the species. The results of this study will help to understand the effects of translocation, for mitigation and conservation on rattlesnakes, help to contribute to the overall understanding of translocation, and guide future research on the subject.
Coffman, Jacob A., "Effects of Translocation on Eastern Black-Tailed Rattlesnakes (Crotalus ornatus) in the Northern Chihuahuan Desert" (2023). Lewis Honors College Thesis Collection. 17.
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