The migration has been going for almost two months now. Her legs are tired, the sun beats down, the rain seems a far off dream. Yet, she still puts one foot in front of the other. What for? The sweet grass that comes with the rains, that provide the nourishment her calf needs to grow and survive. Bodies are pressed together, a pulsating artery in the savanna of animals rushing in a anticipation to get the plains. The risks are evident.She has seen the crocodiles writhe in the water, their jaws snapping at legs rushing by. She will cross the river, perhaps avoiding death. Once passed the river, there are still many dangers she will face; exhaustion, dehydration, hunger, or an unlucky encounter with an opportunistic predator. However, instinct and the pull of the herd is strong and she will continue her migration: even if it kills her.
The migration of 1.3 million wildebeest in the Serengeti-Mara Ecosystem is arguably one of the most awe-inspiring sights. Throngs of herbivores travel across vast distances in an effort to follow the rains and the grass. But why is knowing why and how an animal moves important?
A central question in ecology: animal movement
With strings attached to their legs, John James Audubon, became the first person to record the return of migratory birds in the following spring in the early 1800s. Charles Darwin discussed the idea of ‘home areas’ for many species. The idea of animal movement ecology is not new. However, the importance of this discipline is gaining more recognition.
Often, there is little data on where, why and how species move. However, this information is critical to making management decisions. Perhaps a better way to answer the question of why studying animal movement is important is to explore just a few of the studies of this arm of ecology and how the data has bettered conservation decisions.
Planning for fisheries
Bycatch, whereby other sea creatures are caught in commercial fish nets, is a serious problem around the world. Populations of leatherback turtles have plummeted by 90% over recent decades from fishery mortality, habitat loss and the unsustainable harvest of their eggs. A study into their migrations from Costa Rica showed that the turtles travelled to the South Pacific Gyre. It had been previously assumed that the leatherback turtle population migration had a highly dispersed pattern. This information was used to identify areas of potential fisheries bycatch and set up dynamic and temporary closure for fishing of the migration route to prevent fishery mortality.
Planning for habitat change
Lisovski et al (2016) demonstrated how studying migratory shorebirds in East Asian–Australasian Flyway could help to conserve a threatened species in a changing environment. Using geolocators, the feeding and resting sites of the migratory Sanderlings were tracked. Five key areas were identified in China for potential conservation or special protection sites as it was shown that the Sanderlings were using the coast of the Yellow Sea as stopover sites. The data was also highlighted as a source of information of how the species will respond to changes in the Flyway habitats.
Predicting poaching hotspots
There have been multiple studies that have used animal movement data to help predict potential poaching hotspots. Explaining the spatial distribution of species affected by poaching can help to manage and protect vulnerable populations. With populations of elephants plummeting in Africa by 100,000 individuals and costing $25 million in lost tourism revenue per annum, studies to better protect this iconic species are desperately needed. A study of elephant movement in the Zambezi Valley in Zimbabwe using geographic information systems (GIS) showed that hot spots for poaching of elephants were typically close to water sources and dense vegetation cover. This data could be used to implement anti-poaching initiatives in the areas identified as poaching hotspots.
Revealing new migration routes and managing for development
A ground-breaking study into the migration of Burchell’s zebra in Namibia and Botswana in Africa revealed the longest migration of a terrestrial mammal in 2014. GPS readings from collars attached to the zebras showed a migration that spanned from Namibia to the south of Botswana that was not driven my water or resource availability, but by a genetic or, perhaps, cultural reason for the 500 km migration. The study highlighted the need for animal movement knowledge before development of roads, fences or settlements that could impede the migration. Furthermore, the study provided evidence in supporting the proposed Kavango-Zambezi Transfrontier Conservation Area that covered the migration route.
Reducing human-wildlife conflict
One of the main uses of monitoring animal movement is to facilitate the reduction of human-wildlife conflict. Studies into ranging patterns and movement of animals are crucial in areas where the human population is growing and encroaching on wildlife habitat. By tracking wild dogs and dingoes in Australia, McNeill et al (2016) collected information on home ranges of these animals using GPS collars. It was found that wild dogs and dingoes are often found within an urban-bushland matrix in close proximity to humans. Dingoes and wild dogs pose a risk to human health and safety. However, by tracking their movements for the first time, management efforts could be decided to relocate dingo populations out of urban areas to decrease human-wildlife conflict.
Migratory effects on other wildlife
Animal movements are part of numerous and nested interactions with other species. By researching the movement of certain species, the life history of other species can be delineated. Lee et al (2016) conducted a study that showed that lions were selecting migrating wildebeest and zebra as the prey items instead of giraffe calves, which has a significant effect on giraffe population dynamics. This study highlighted that the decline of migratory populations will have serious consequences on other species population dynamics.
Setting hunting quotas
When ungulate populations increase beyond their normative values, serious habitat destruction can accrue. In researching the migratory patterns of male red deer in the Western Carpathians in Slovakia, Kropil et al (2015) were able to suggest hunting options in the region. With data from Konopka and Kastier 2013 which showed that red deer populations were 57% higher than normal and were damaging the forest, Kropil et al (2015) could suggest areas hunting quotas in the winter feeding grounds of the red deer.
It is often assumed that we know where animals travel. What is clear is that we know very little about the journeys of the species on our planet. However, the snapshot of studies covered here has shown how we can use animal movement data to reduce human-wildlife conflict, assign protected areas and understand the life histories of so many species. Perhaps we should follow their journeys and our path to protecting the world’s species may become a little clearer.