Utility of Satellite Telemetry and GPS Tracking in Wildlife Conservation

Introduction

Satellite telemetry and GPS tracking are relatively new technologies being used in the field of conservation biology. Prior to the development of these techniques, information regarding the movements, behaviors and life histories of wildlife populations were inferred from eyewitness accounts and observations, and the data collected was often extremely biased (James, Ottensmeyer & Myers, 2005, Gredzens et al., 2014). Management and conservation decisions were based on sparse, incomplete pools of knowledge. Telemetry allows scientists to study wildlife populations with minimal interference, and track animal movements from afar. As the human population continues to expand, it often finds itself in contention with wildlife populations for habitat, resources and space. Conserving large chunks of habitat for wildlife has become more difficult with increased human demands for land and natural resources. Tracking migration routes and natural ranges of wild animals using GPS and satellite telemetry allows conservationists to identify critical habitats necessary for the survival of specific wildlife species. Identifying these habitats will allow scientists to educate the local human populations on strategies to coexist with the wildlife around them, conserve necessary natural resources and utilize expendable natural resources from these areas in a way that creates minimal harm. Understanding the impacts of GPS and satellite telemetry tracking of wildlife populations on conservation biology is essential in assessing how these technologies have contributed to more efficient ecological and biological conservation efforts around the world.

The Mechanics of Satellite Telemetry and GPS Tracking

To study wildlife populations using satellite telemetry or GPS tracking, individuals from a given population are captured and fitted with a GPS collar or satellite tracking device. The individuals are then re-released back into the wild, and their movements are studied using data from the tracking device. One of the most widely used systems is Argos. The individual’s location is transmitted to at least two active satellites above the Earth’s atmosphere, and this data is transferred to Argos Worldwide Tracking and Environmental Monitoring Service stations on the ground in the form of latitude and longitude data points (Higuchi, 2012). The data is then used to infer movement patterns and habitat use.

Great Blue Heron, Prime Hook Wildlife Refuge, Delaware
Great Blue Heron, Prime Hook Wildlife Refuge, Delaware | Source

Impacts of Telemetry on Mitigating Habitat Loss

Habitat Identification

One major challenge facing conservation biologists is identifying critical habitats, and determining which habitats are vital to the survival of wildlife populations. It is becoming increasingly difficult to conserve large chunks of natural land, and habitat loss is one of the major threats to modern wildlife. It is vital that conservation efforts target habitat that is ideal for wildlife populations. The most efficient conservation strategies are based on telemetry evidence of which habitats wildlife selects, rather than informed speculation (Onorato et al., 2011). Using telemetry data to determine critical habitats for wildlife ensures that the proper habitats will be marked for conservation, and resources used to full effect. Habitat identification can be challenging because of international boarders, inaccessibility and vastness of area (Tancell et al., 2013 & Schofield et al., 2013). Telemetry allows scientists to remotely monitor animal movements over large areas and document time spent in specific areas.

A study performed by Tancell et al. (2013) used satellite transmitters to track wandering albatross (Diomedia exulans) to determine which foraging habitats were critical to the species during their chick-rearing season. Since the birds spend the majority of the rearing season at sea, this data was previously unknown. The transmitters showed that the albatross’ speed slowed and turning rate increased in specific areas. This behavior is congruent with foraging, so the areas where the albatross’ movements displayed these characteristics were identified as feeding grounds. Previously, it had been widely accepted that the albatross primarily foraged in waters near the shoreline, but the data from this study showed that foraging grounds in off shore areas were of more importance than those near the coast (Tancell et al., 2013). Satellite telemetry allowed for the identification of previously unrecognized critical habitat, and due to the vastness of area and remoteness of these locations, it is unlikely that this data could have been collected without this technology.

Studies performed by Shofield et al. (2013) and Onorato et al. (2011) demonstrate how telemetry is useful in helping scientists understand why a certain habitat is selected by a species. Schofield et al. (2013) studied the movements of loggerhead turtles (Caterra caterra) using satellite telemetry. The data collected allowed scientists to identify the characteristics of critical foraging habitats, such as depth and temperature. This data was then used to make conservation recommendations for several sites in the Mediterranean Sea. Onorato et al. (2011) used telemetry to study the Florida panther (Puma concolor coryi), and found that in addition to the previously recognized forested habitat required by the species, open and edge habitats were also of importance for hunting purposes. The use of telemetry to study animals that are either inaccessible, like the loggerhead turtle, or wary of human disturbance, like the Florida panther, provides vital information on the habitat selection of these species, as well as the characteristics that make these habitats important.

Prioritizing Habitats for Conservation

Identifying critical habitats is the first step in prioritizing habitats for conservation. To optimize both resources and conservation benefits, selecting habitats for conservation is ideally performed in a triage fashion. The most vital habitats must be identified and then conservation efforts must be allocated based on site importance. Since resources are limited, “it is important to ensure that governments and environmental agencies select optimal sites for regulation” (Schofield et al., 2013, p.842). The previously mentioned study performed on loggerhead turtles by Schofield et al. (2013) found that 65 percent of the turtle population used foraging sites concentrated in a specific area, and 33 percent of these sites either overlapped or were in proximity to already protected areas. Expanding protected areas to include these sites would protect a significant portion of the population with limited management efforts (Schofield et al., 2013). These sites were highlighted for immediate conservation.

Leatherback turtles (Dermochelys coriacea) were studied using telemetry by James, Ottensmeyer & Myers (2005), and the data showed that previous conservation efforts had been focusing on non-critical habitats. The key foraging areas identified in the study fell outside of the areas that had traditionally received the most management attention. Recommendations for the re-prioritization of critical foraging sites were given in light of the new data. Telemetry data proved to be a vital tool in identifying critical habitats, and making conservation recommendations that would best benefit the species being studied.

Perching songbird at Blackwater Wildlife Refuge, Maryland
Perching songbird at Blackwater Wildlife Refuge, Maryland | Source

Telemetry and Mitigating Genetic Degradation and Preserving Ecological Structure

Connecting Populations and Promoting Genetic Diversity

Habitat loss results in decreased numbers of individuals within a population, which results in decreased genetic diversity. Lower genetic variation can lead to increased population sensitivity to disease, decreased individual fitness and flexibility in coping with environmental challenges, decreased average fitness of a population and lowered resilience and long-term adaptability (Castellblanco-Martinez et al., 2013). Preserving genetic diversity and connecting sub-populations of a species is vitally important to preserving the fitness of that species. Satellite telemetry and GPS tracking can be used to monitor animal movements and identify barriers between sub-populations. Once these barriers are identified, measures can be implemented to connect breeding populations. For example, Onorato et al. (2011) showed that the Florida panthers living in protected areas were moderately isolated from panthers living outside of these areas, reducing gene flow between the two populations. The authors proposed conserving a corridor connecting the two populations to ensure that gene flow did not degenerate further. Another study performed by Castellblanco-Martinez et al., (2013) used satellite telemetry to track Antillean manatees (Trichechus manatus manatus) to determine movements, home ranges and high use areas for conservation. It was found that many manatee populations in the Caribbean region were isolated from one another, putting them at risk for genetic degeneration. As a result of this data, Castellblanco-Martinez et al. (2013) suggested movement corridors be conserved to promote intermingling of colonies and facilitate genetic exchange.

In addition to preserving movement corridors, wildlife passes can also be built to facilitate gene flow between populations. Usually wildlife passes are built over roads or other infrastructure that is creating a potential barrier for wildlife. A study performed by Colchero et al. (2011) used data from GPS tracking to determine how a road running through the Mayan forest in Mexico was affecting the local jaguar (Panthera onca) population. The study found that jaguars avoided the road where even low levels of human activity were present, and the scientists were able to identify a one kilometer strip of road where the jaguars crossed most frequently. This area was the location in which the authors suggested a wildlife pass be built. Using telemetry and tracking to determine ideal locations for wildlife passes is important because it “provide[s] direct evidence of the exact locations animals are using as crossings” (Colchero et al., 2011, p.164). Wildlife passes are an important tool used to facilitate gene flow and maintain genetic diversity.

Preserving Migration Routes

Migration routes can be difficult to study due to the large distances covered in a relatively short period of time. Many migratory animals will stop several times during migration to feed and rest. Identification of important stopover sites is critical to ensuring successful migration. Satellite telemetry allows for the study of detailed migration routes, seasonal differences in migratory patterns, locations of important sites and the identification of conservation issues (Higuchi, 2012, Chevallier et al., 2011). Over the past century, there has been a steep decline in migratory bird populations, possibly due to a lack of suitable stopover sites along migratory routes (Chevallier et al., 2011). A tracking study performed by Chevallier et al. (2011) followed the migration of Black Storks (Ciconia nigra). By analyzing the amount of time the birds spent at specific sites along the migratory route, the authors identified several important stopover sites. Interestingly, there was some variation in which sites the birds stopped at, suggesting that the storks lack strong site fidelity, and thus the characteristics of optimal sites for conservation were more important than the specific sites themselves. Optimal stopover sites provided abundant access to food and water while ensuring as much protection from predation and other risks as possible, so sites for conservation were chosen based on these characteristics (Chevallier et al., 2011). Using the telemetry data, the authors were able to protect the migration route of the storks by conserving six critical stopover sites.

Preserving Ecological Communities and Structure

For ecosystems to function properly and for species to flourish within any community, it is essential that the structure of that community be preserved. The complex relationships between species within an ecological community is a delicate balance necessary to the health and longevity of the entire system. A study performed by Cozzi et al. (2013) used GPS tracking to examine how natural and man-made barriers affected trophic structure among large carnivores in Northern Botswana. African lions, spotted hyenas (Crocuta crocuta), African wild dogs (Lycaon pictus) and cheetahs (Acinonyx jubatus) were fitted with GPS collars, and there movements and interactions were studied for a four year period. It was found that the barriers altered their natural movement patterns, and disrupted the spatial distribution and relationships between co-occurring species by excluding some species, but not others, from sections of habitat. This affected the ecological balance within the community (Cozzi et al., 2013). The data from the tracking study was then used to make suggestions for increased permeability of the barriers. Without tracking, the subtle changes in how the barriers affected the ecological structure of the community would have been extremely difficult, if not impossible, to discern.

Prime Hook Wildlife Refuge, Delaware
Prime Hook Wildlife Refuge, Delaware | Source

Telemetry and Mitigating Human-Wildlife Conflict

Commercial Activities and Expansion of Infrastructure

Human expansion is often in direct conflict with wildlife (Panzacchi, Van Moorter & Strand, 2013, Dickson & Smith, 2013). Habitat is often destroyed to expand infrastructure, and the harvesting of natural resources can pose myriad threats to wildlife in areas surrounding this activity. Telemetry is a useful tool in determining how human activities affect wildlife populations. The fragmentation of migration routes by human infrastructure can have a devastating effect on wildlife populations. As Panzacchi, Van Moorter and Strand note, “the ongoing expansion of human-dominated areas and the rapid development of transportation infrastructure interfere with the persistence of large-scale animal movements; many of the most spectacular migrations worldwide have either disappeared, or are in steep decline” (2013, p.16). The Norwegian reindeer population, for example, used to be comprised of two to three large groups, but is now fragmented into more than 23 small subpopulations, and several highly important migration corridors have been lost over the past century (Panzacchi, Van Moorter & Strand, 2013). Panzacchi, Van Moorter and Strand (2013) studied the migration of wild reindeer (Rangifer tarandus tarandus) in Norway by fitting individuals with GPS collars and tracking their movements. A cabin-lined road bisects the reindeers’ migration route, and this study sought to determine how the road affects the behavior of the reindeer during migration. Additional development for the area has been proposed, so assessing the impact of the road on the natural migration of the reindeer is an important factor in hypothesizing how further development may affect the population. The study found that the road delayed spring migration to calving grounds because the reindeer would spend up to five days finding a safe area to cross. Movement patterns were highly disturbed by the traffic and increased human activity due to vacationers. During fall migration, when there is less human activity, the migration route is much less disturbed. Overall, the authors found that “the planned construction of a large number of recreational cabins in the migration corridor has the potential to threaten the migration and obstruct the access to the calving ground” and suggest that the relatively narrow migration corridor not be disturbed or developed further (Panzacchi, Van Moorter & Strand, p. 15).

In addition to recreational activities, commercial activities also have the potential to disturb wildlife. GPS tracking and telemetry can be used to identify habitats where the pursuit of commercial activities may create more harm than it is worth. The South Beaufort Sea, for example, has been identified as an area with high oil and gas potential (Dickson & Smith, 2013). It is also a critical habitat for king and common eiders (Somateria spectabilis and Somateria mollissima). To determine if the areas identified for resource harvesting overlapped with eider habitat, Dickson and Smith (2013) used GPS tracking to monitor the movements of 51 birds over a five year period. The site studied in the Beaufort Sea is used by almost the entire Canadian eider population and is the final staging area prior to breeding, meaning that the conditions encountered there carry over to influence reproduction. The findings showed that areas marked for oil and gas exploration significantly overlapped with critical eider habitat, and authors warn that if there were to be a spill in the area it could be “catastrophic” for the eider population (Dickson & Smith, 2013, p. 777). The authors also identified the risks of further oil exploration in the eider habitat. These included oil spills, disturbance due to air traffic, bird collisions with machinery, changes to invertebrate community structure and abundance (the birds’ main food source) and degradation of foraging habitat. The authors suggest that the area not be explored further for oil and gas because the risk to the eider population is too great (Dickson & Smith, 2013). The precise movement patterns and habitat use identified by GPS tracking would not have been possible to discern without this technology, and the risks to the eider population would not have been identified prior to drilling. In this way, telemetry is a powerful tool that can be used in assessing the risks of commercial activities before they begin, and before large sums of money have been invested in specific ventures.

Co-existence

One of the major challenges in conservation biology is creating strategies for successful coexistence between humans and wildlife. GPS tracking and satellite telemetry can be used to study wildlife movements and human-wildlife interactions to help mitigate potential conflicts. Valeix et al. (2012) used telemetry to track African lions living in a wildlife preserve bordered by pastures used by farmers for raising livestock. In Africa, conflict between humans and large carnivores is a prevalent conservation issue. Farmers will often retaliate against large carnivores for the loss of livestock. Data from the study showed that the majority of livestock killed by lions had strayed from the herd. The authors suggested more effective management of herds to reduce lion-human conflict. Effectively using livestock enclosures, not leaving livestock unattended at night and proper husbandry practices would likely deter lions from attacking (Valeix et al., 2012). The telemetry data allowed scientists to determine the time of day lions were most likely to attack, as well as where livestock were at the most risk, and make suggestions to reduce conflict accordingly.

A study performed by Coleman et al. (2013) tracked both humans and grizzly bears (Ursus arctos horribilis) in Yellowstone National Park to determine if areas with restricted human access were effective in reducing the chance of interactions between humans and bears. In addition to human mortality risk associated with grizzly bear encounters, the authors note that “human presence can alter wildlife behavior and ultimately change foraging patterns, modify intra- and interspecific interactions, increase physiological stress, reduce survival, decrease reproductive output and lead to habituation” (Coleman et al., 2013, p. 1311). Decreasing interactions between grizzly bears and humans benefits both species. The GPS data showed that the bears were twice as likely to venture into human recreational areas when bear management areas opened to human activity. Restricting human access to bear management areas decreases the risk of human-bear interaction and increase foraging opportunities for the bears, who will often become defensive if they perceive that their prey is threatened (Coleman et al., 2013).

Conclusion

Although GPS tracking and satellite telemetry have only been used in wildlife conservation studies for a couple decades, these technologies have made significant contributions to the field. Conservation biology would further benefit from telemetry studies that use larger sample pools and track individuals for longer periods of time. Data that was previously unknowable due to geographical restrictions, range size and behavioral changes due to human presence is now attainable. Telemetry has proved to be an invaluable tool in habitat identification, risk assessment, the preservation of ecological structure and many other facets of the field of conservation biology.

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