As humans continue to change the landscape, migratory connectivity becomes increasingly important. Understanding the affects of proposed zoning changes or infrastructure projects must take into account migratory routes, breeding-wintering population dynamics, and the cascading effects of disrupting one or more of these areas. Considerations include:
- Direct impacts like fatal collisions with infrastructure
- Indirect effects like increased vulnerability imposed by seasonal interactions
Collision of aerial migrants with buildings (particularly windows) and other structures is a worldwide problem (approximately one billion annual birds kills in the United States alone). Resident urban species rarely strike buildings, and migratory songbirds are disproportionately affected.
- January, 2001 5,000 red-winged blackbirds collide with buildings and are killed in Arkansas
- Night-migrating birds become “trapped” by the bright lights of cities and die from collision or exhaustion
- Consequences of collision mortality is not fully known because we do not know where individuals breed
- Impacts could be diffused throughout the entire range of a species, or may be focused on a handful of populations
- Understanding where, when, and how birds migrate can help us to plan infrastructure and know when to keep the lights off
A side-effect of urbanization is pollution. Many cities around the world have poor infrastructure and few regulations to deal with human and industrial waste, particularly in developing and undeveloped regions (e.g. Tamilnadu, India and Accra, Ghana).
- Water pollution can damage habitat and lead to severe mortality among waterbirds and aquatic animals
- Some migrant animals (e.g. great white cranes and salmon) will reject outright polluted or otherwise human-altered environments. Ultimately, this reduces breeding success for the population and can cause mortality
- Knowing where migratory populations are coming from and going to will help us elucidate population impacts from pollution, long-term toxicity, and how pollutants are moved from urban environments to other locales
Vehicular collisions & roadway-induced habitat fragmentation
While the effects of infrastructure and pollution appear to be localized, roadways are ubiquitous and widespread. Vehicular strikes with wildlife may cause significant damage to migratory populations as well as to humans involved in these accidents.
- Habitat quality near roads is poor
- Culverts may be impassable to migratory fish
- Wildlife passages for ungulates are often avoided in favor of traditional migratory corridors
- Migratory connectivity can help us know where to place wildlife corridors and reserves that protect important habitat for migratory populations
- Governments must account for migratory pathways and address the stress of roads and traffic on wildlife populations.
- A highway proposed for the Serengeti would severely disrupt wildebeest migratory route
- Belford, D.A. and W.R. goud. 1989. an evaluation of trout passage through six highway culverts in Montana. North American Journal of Fisheries Management 9: (4) 437-445.
- Bernardino, F.S. Jr., G.H. Dalrymple. 1992. Seasonal activity and road mortality of the snakes of the Pa-hay-okee wetlands of Everglades National Park, USA. Biological Conservation 62: (2) 71-75.
- Boadi, K.O. and M. Kuitunen. 2002. Urban waste pollution in th Korle Lagoon, Accra, Ghana. The Environmentalist 22: (4) 301-309.
- Dahle, B., E. Reimers, and J.E. Colman. 2008. Reindeer (Rangifer tarandus) avoidance of a highway as revealed by lichen measurements. European Journal of Wildlife Research 54: (1) 27-35.
- DeMaynadier, P.G., and M.L. Hunter, Jr. 2000. Road effects on amphibian movements in a forested landscape. Natural Areas Journal 20: (1) 56-65.
- Evans, M.I., P. Symens, and C.W.T. pilcher. 1993. Short-term damage to coastal bird populations in Saudi Arabia and Kuwait following the 1991 Gulf War marine pollution. Marine Pollution Bulletin 27: 157-161.
- Foppen, R. and R. Reijnen. 1994. The effects of car traffic on breeding bird populations in woodland. II. Breeding dispersal of male willow warblers (Phylloscopus trochilus) in relations to the proximity of a highway. Journal of Applied Ecology 31: 95-101.
- Forman, R.T.T. and R.D. Deblinger. 2000. The ecological road-effect zone of a Massachusetts (U.S.A.) suburban highway. Conservation Biology 14: (1) 36-46.
- Gagnon, J.W., T.C. Theimer, s. Boe, N.L. Dodd, and R.E. Schweinsburf. 2007. Traffic volume alters elk distribution and highway crossings in Arizona. The Journal of Wildlife Management 71: (7) 2318-2323.
- Guyot, G. and J. Clobert. 1997. Conservation measures for a population of Hermann’s tortoise Testudo hermanni in southern France bisected by a major highway. Biological Conservation 79: (2-3) 259-256.
- Hager, S.B., H. Trudell, K.J. McKay, S.M. Crandall, and L. Mayer. 2008. Bird density and mortality at windows. The Wilson Journal of Ornithology 120 (3): 550-564.
- Klem, D. 2010. Avian mortality at windows: the second largest human source of bird mortality on earth. Proceedings of the Fouth International Partners in Flight Conference: Tundra to Tropics : 244-251.
- Mohanraj, R., M. Sathishkumar, P.A. Azeez, and R. Sivakumar. 2000. Pollution status of wetlands in urban Coimbatore, Tamilnadu, India. Bulletin of Environmental Contamination and Toxicology 64: (5) 638-643.
- Ogden, L.J.E. 1996. Collision course: the hazards of lighted structures and windows to migrating birds. Fatal Light Awareness Program (FLAP). Accessed 3 Oct 11.
- Robinson, S.K. and D.S. Wilcove. 1994. Forest fragmentation in the temperate zone and its effects on migratory songbirds. Bird Conservation International 4: 233-249.
- Saunders, R.L. and J.B. Spraugue. 1967. Effects of copper-zinc minimg pollution on a spawning migration of Atlantic salmon. Water Research 1: (6) 419-432.
- C-F. 1970. Changes in fish populations and migration in relation to increased sewage pollution in Little Patuxent River, Maryland. Chesapeake Science 11: 91) 34-41.
- Yosef, R. 2009. Highways as flyways: time and energy optimization in migratory Levant sparrowhawk. Journal of Arid Environments 73: (1) 139-141.