Tim-Hee Chen is an assistant professor at the Wildlife Conservation Institute of Pingtung University of Science and Technology, Taiwan
Because of illegal poaching and smuggling, the number of snake-eating turtles and chai coffin turtles seized and sheltered in Taiwan in the past ten years has exceeded 10,000, and the final disposal of these rescued and conserved turtles is a difficult problem for relevant units. In the past, different disposal plans have been proposed, including the establishment of long-term containment and seed preservation centers, the transfer of long-term shelters to domestic and foreign non-governmental institutions for long-term shelter, the experimental use of commercial artificial breeding, the provision of research and use by academic institutions, the release of wisdom in cooperation with religious groups, the release of wild people back into the natural environment to supplement or the reconstruction of wild populations. However, since the snake-eating turtle and the chai coffin turtle are considered endangered nursery turtles, all conservation or protection measures should focus on the survival of wild populations, and under the long-term heavy containment pressure, it is necessary and urgent to evacuate the shelter animals with too high density or too many people, and it is still necessary to consider whether it is in line with the general direction of the conservation of wild populations.
Snake-eating turtles and wood-coffin turtles are at risk of death, predation or poaching. Image source: Tim Chan.
Wilding of wild turtles for conservation purposes is a complex and expensive process! If the purpose is only to dispose of the animals that are seized and seized, of course it is another matter. Recently, in order to relocate more than 1,000 tortoises at a training base, the U.S. Marine Corps is expected to spend 50 million US dollars (NT$1.5 billion) and monitor for 30 years to ensure that the tortoises can adapt to the new environment and successfully establish a population with ecological functions after relocation. It's easy to get the animals out, but it's a long way to confirm the success of the wild releases! Often we can only see a few successful cases, and more cases of failure or no monitoring and evaluation. Wild animals are often considered "Set free", but most of the wild release process is only "Let go", and what happens in the wild environment is not clear. The Let got process is often packaged as a carnival event with slogans, but the actual results after wild releases are often the presentation of hard and long cruel facts.
<h1>Wild release in situ vs field release in situ</h1>
Returning wildlife to their habitat is certainly the best option, but many realities limit the likelihood that the wild turtles can return home safely, unless the causes of their population decline have been ruled out or effectively controlled, such as illegal poaching and habitat degradation. At present, when Taiwan shelters and preserves turtles to be released back into the natural environment, in the case of unsolved poaching threats, choosing to return to unsafe original habitats is not the best choice, the chance of repeated poaching is very high, it is easy to become a waste of limited resources, and the actual benefits to the conservation of wild populations are limited. The option of wild placement in a private ecological farm or a religious group nursery is not easy to ensure for a long time that the type of private land use and the disposition of ownership will not change, and the risk of poaching will not be reduced by private land, which can only be regarded as another type of shelter, not a long-term solution.
The morphology of wild turtles varies greatly, and it is not easy to determine their origin by their appearance. Image source: Tim Chan.
Many fear that ex-situ releases will create genetically mixed doubts that have long been an insoluble problem; animals seized in ports or at sea are highly unlikely to trace their origins. Island-wide poaching has made it impossible to sample and analyze the population differentiation of wild snake-eating turtle populations; the so-called population differentiation is mainly to analyze the differences in gene frequency between different populations, and it is not practical to use phenotype or genotype to determine the source of individuals. Turtles in different regions of Taiwan will have obvious morphological differences, but these differences are much more affected by environmental factors than the variation of genetic composition. The distribution of snake-eating turtles is relatively low due to human interference, but the chai coffin turtle population in Taiwan has long been not a natural distribution; the wild often finds that the edge of the dorsal carapace is drilled and released by the chai coffin turtle, and many existing groups are artificially introduced, not naturally distributed, and it has long been impossible to determine the trend of natural differentiation. Taiwan has long allowed the release of spotted turtles caught or artificially bred in the wild, and it is not unusual for chai coffin turtles and snake-eating turtles to appear in the booths of guandu palaces in the past.
When the original habitat cannot be determined or the threat of poaching cannot be ruled out, or even if the original habitat has been destroyed or disappeared, translocation is an inevitable choice. Ex situ wild release measures are also one of the important means of turtle conservation, for the habitat disappeared or deteriorated population for resettlement, increase the number of threatened populations or increase genetic diversity and population reconstruction and other cases of the use of turtles for wild release or reintroduction, including the original habitat of the human use of development (such as new town development, military facilities, solar power generation facilities, road construction), endangered population reconstruction, seizure and shelter and rescue and recovery of individual wild release, etc., but due to the different reasons and purposes and methods of wild release, Actual results vary widely. Most of the wild release measures have not been tracked and evaluated, and the actual results cannot be determined.
The tortoise release program for the purpose of conservation is mainly to enable wild animals to adapt, survive, survive and survive in the safe and suitable habitat selected in advance, and to establish a stable range of activities, and finally to maintain a naturally reproducible and ecologically functional population. If the animals after wild release cannot adapt to the new environment, in addition to not surviving, they will often quickly leave the expected wild release range, increasing the chance of accidental death and poaching. Taking the box turtle in the eastern United States as an example, the suitable habitat area for the long-term stability of the wild release population is about 500 hectares, and there are not many ideal wild release sites that can meet the conditions, and the assessment, operation and monitoring of animal wild release need to be more cautious.
<h1>Soft wild play vs hard wild put</h1>
Snake-eating turtles that have not been temporarily stocked in captivity have migrated over long distances. Image source: Tim Chan.
The wild release methods of many wild animals can be divided into hard wild release (direct wild release) and soft wild release (progressive wild release); animals temporarily keep the soft wild release in the wild release site before wild release, which can reduce the distance of movement in the early stage of wild release and shorten the time to establish the range of activities. Studies related to the wild release of tortoises have found that wild release animals often have a tendency to leave the wild release site without direction in the early stage of wild release (about 1 month), resulting in wild release individuals staying away from suitable and safe habitat environment, resulting in a decline in survival rate and unable to track and monitor. The death of wild animals is often related to the distance from the field release site and the use of an unsuitable winter environment, reducing the opportunity for long-distance movement in the early stage of wild release, ensuring that the wild animal can stay in a suitable and protected range, which is one of the key factors in judging the success or failure of the wild release plan.
Snake-eating turtles that have not been temporarily released in captivity and directly released have moved more than 1.2 kilometers in a year, and continue to move directionlessly even for several years after wild release. After a few days to several weeks of captivity at the wild release site, the distance of movement after the wild release and the chance of staying away from the wild release site will be significantly reduced. The distance of 1.2 km after the release represents the range away from most of the wild release sites, which may have crossed adjacent valleys, ridges or roads, or even entered the range of agricultural land or frequent human activities.
Snake-eating turtles become turtles. Photograph: Zhong Chaoren.
The actual benefits of the temporary captivity of aquatic or semi-aquatic turtles in the wild release site are limited, and the distance of movement after wild release is related to the continuity of the spatial distribution of suitable water habitats. In the case of the semi-aquatic chai coffin turtle, its population composition and spatial use are typically metapopulation, which will be seasonally migrated between different waters; if the wild release site is selected away from other suitable water environments, the farther away the migration distance using the land environment after release, the lower the chance of returning to the field release site, and the higher the risk of death. If the wild release site is close to other ponds, mud, ditches, grass and other environments that can be used for staying, the distance of movement after wild release will be closer, and the chance of returning to the field release point will increase and the time to establish a stable activity range will be shorter.
Snake-eating turtles released in the wild during the active season can move more than 500 meters within a month after the wild release. Image source: Tim Chan.
Terrestrial species (such as snake-eating turtles) are directly released before adapting to the new environment, and long-distance linear migration away from the wild release point often occurs in a short period of time after the wild release, which is related to the animal's unfamiliarity with the new environment or loyalty to the original habitat site; the wild animal is not familiar with the spatial positioning information (such as landmarks), the spatial distribution of the available hiding points, the supply of food resources and the risk of predation in the new environment, and the environmental information such as the loyalty to the specific area has not yet been established, and the positioning and movement cannot be clearly defined. Or constantly search for the original environmental signals; the native individual often shows a more clear and directional movement pattern within the familiar range of activity. Native individuals who have usually adapted to the environment will be more efficient in the use of environmental resources than individuals in the field, especially before adapting to the hot environment, the body temperature regulation, activity, and metabolic rate are affected.
Wild animals should not be just a "let go" release process, you need to shorten the time spent on handling as much as possible, if you need to transport long distances, you can use night transportation to avoid the urgency caused by high temperatures during the day. After temporarily retaining and captivity at the wild release site, not only can the urgency caused by the handling process be reduced, the animal can be familiar with the temperature changes and environmental signals of the new environment for a long time, and after the wild release, it will often stay near the wild release site to explore, and then slowly leave the wild release site, and the opportunity to quickly leave will be reduced.
Wild season is important!
Empirically, it is believed that wild release at the peak of the turtle season will have more opportunities to adapt to the new environment and have a higher chance of survival, but this is not the case. During the active season, the animals will often quickly leave the wild release site, and the chance of staying in a safe place is low. Snake-eating turtles and chai coffin turtles released in the wild before winter are staying near the wild release point for the first year to survive the winter; the chance of being repeatedly captured and found in the vicinity of the wild release site is significantly higher than that of the wild animals released in the active season. The seasonal selection of animal wild release considers the actual needs and purpose of wild release, and should not only be held in conjunction with the event or released according to fate.
In addition to the soft wild release in temporary captivity, the method of shortening the initial migration distance and reducing the range of activities can also be used to force the suspension of activity. In temperate or subtropical zones, the forced suspension of activity soft wild release is carried out before wintering in the late stage of the active season, forcing animals to find a suitable winter environment near the wild release site in the short term before the temperature drops and stops the activity, and there will be a longer period of adaptation to the environmental information near the wild release site after the activity is stopped, which can reduce the chance of long-distance migration of wild release individuals. However, it is necessary to assess whether the new environment of wild release can provide accessibility to safe and suitable winter crossing sites for wild animals, so as to avoid death or predation during winter crossing.
Juveniles of the wood-coffin turtle. Image credit: Skink Chen (CC BY-NC-ND 2.0)
Hunting for sheltered animals shouldn't just be Let go animals! If the purpose of wild release also has the added value of conservation, from the location and season selection, the wild release process needs to be evaluated and planned, and more importantly, the safety of wild animals needs to be ensured, and through conservation patrols, animals that are difficult to regain their lives are not repeatedly poached, and monitoring and evaluation are needed, and efforts to investigate, rescue and shelter should not be wasted!
The tracking and monitoring of wild animals should be regarded as a long companionship process, and the problems that may be encountered in each case are not the same, and they need to be corrected through continuous discovery and adjustment, which may be poaching, disease, predation, cliff fall, road killing, etc., and even malnutrition, which cannot be a perfect ending. No tracking, monitoring, and evaluation doesn't mean nothing happens; but without trying, the animals that are seized cannot safely return to their natural environment.
※ The author of this article, Chen Tianxi, is an assistant professor at the Wildlife Conservation Institute of Pingtung University of Science and Technology in Taiwan, and the article is reproduced from Chen Tianxi's Facebook.