The Last Mile: How to Sustain Long‐Distance Migration in Mammals

Abstract

Among Earth's most stunning, yet imperiled, biological phenomena is long-distance migration (LDM). Although the understanding of how and why animals migrate may be of general interest, few sitespecific strategies have targeted ways in which to best retain such increasingly rare events. Contrasts among 29 terrestrial mammals from five continents representing 103 populations indicate that remnant long-distant migrants have poor long-term prospects. Nonetheless, in areas of low human density in the Western Hemisphere, five social and nongregarious species, all from the same region of the Rocky Mountains (U.S.A.), still experience the most accentuated of remaining New World LDMs south of central Canada. These movements occur in or adjacent to the Greater Yellowstone region, where about 75% of the migration routes for elk (Cervus elaphus), bison ( Bison bison), and North America's sole surviving endemic ungulate, pronghorn (Antilocapra americana), have already been lost. However, pronghorn still migrate up to 550 km (round-trip) annually. These extreme movements (1) necessitate use of historic, exceptionally narrow corridors (0.1-0.8 km wide) that have existed for at least 5800 years, (2) exceed travel distances of elephants ( Loxodonta africana) and zebras ( Equus burchelli), and (3) are on par with those of Asian chiru ( Pantholops hodgsoni) and African wildebeest (Connochaetes taurinus). Although conservation planners face uncertainty in situating reserves in the most biologically valued locations, the concordance between archaeological and current biological data on migration through specific corridors in these unprotected areas adjacent to the Yellowstone system highlights their retention value. It is highly likely that accelerated leasing of public lands for energy development in such regions will truncate such migrations. One landscape-level solution to conserving LDMs is the creation of a network of national migration corridors, an action in the Yellowstone region that would result in de facto protection for a multispecies complex. Tactics applied in this part of the world may not work in others, however, therefore reinforcing the value of site-specific field information on the past and current biological needs of migratory species. LaÚltima Milla: Como Sostener la Migración de Larga Distancia en Mamíferos Resumen: Entre los fenómenos biológicos más asombrosos, pero en peligro, de la Tierra está la migración de larga distancia (MLD). Aunque el entendimiento de cómo y porque migran los animales puede ser de interés general, pocas estrategias sitio-específicas han encontrado formas para retener tales eventos cada vez más raros. Los contrastes entre 29 mamíferos terrestres de cinco continentes que representar a 103 poblaciones indican que las MLD remanentes tienen perspectivas pobres a largo plazo. No obstante, enáreas con bajas densidades humanas en el Hemisferio Occidental, cinco especies sociales y no gregarias, todas de las misma región de las Montañas Rocallosas (E.U.A.) aun experimentan las MLD más acentuad...

World heritage, wilderness and large landscapes and seascapes

“…Conservation of these remaining large wilderness areas is important for many reasons. They are crucial for biodiversity because smaller areas tend to lose much of their biodiversity over time, in particular wide-ranging mammals and migratory species that need large, intact areas to persist and require wildlife corridors to travel across large landscapes (Wuerthner et al 2015, Noss et al 2012, Worboys et al 2010, Laliberte & Ripple 2004, Berger 2004, Soulé and Terborgh 1999. Larger areas are also important to maximize ecosystem services, for example to protect globally significant carbon stocks (Martin and Watson 2016) or to ensure a high quality freshwater supply (Watson et al 2016).…”

“…Adding additional wilderness areas to the World Heritage List should therefore be a priority. (Chester et al 2012, Berger 2004. The absence of large predators can change community composition, dynamics, and vegetation structure (Ripple et al 2014), which in turn can degrade a site's Outstanding Universal Value.…”

“…These phenomena are integral elements of large-scale ecological processes, making major contributions to resource fluxes, transport, predator-prey interactions and food-web structure within and among ecosystems (Bauer et al 2014) and often playing an essential role in customary livelihoods. However, they are in serious decline globally (Wilcove 2008) and are often insufficiently protected by World Heritage and other protected areas (Berger 2004).…”

“…In the Northern hemisphere, the An increasing global decline in ungulate migrations has been noted in recent years across different regions and species and was attributed to habitat loss and degradation as well as the construction of physical barriers on migration routes (Berger 2004, Bolger et al 2008, Middleton et al 2013), but more and more attention is now being paid to the impacts of climate change (Middleton et al 2013). Protection of the remaining large intact landscapes supporting animal migrations will therefore become more important in preserving this stunning and increasingly rare phenomenon of animal behaviour, which plays an essential ecological role.…”

Habitat Fragmentation by Railways as a Barrier to Great Migrations of Ungulates in Mongolia

“…Both historically and today, the Mongolian gazelle has had one of the longest migrations among terrestrial animals (Berger 2004;Teitelbaum et al 2015). Until the 1930s, this species had a distribution that occupied most of the grasslands in northern China, Mongolia, and southern Russia, but since then its distribution has been reduced to the eastern half of Mongolia and to areas close to the border between Mongolia, China, and Russia ( Fig.…”