Ecological traps are scenarios in which rapid environmental change leads organisms to prefer to settle in poor-quality habitats. The concept stems from the idea that organisms that are actively selecting habitat must rely on environmental cues to help them identify high-quality habitat. If either the habitat quality or the cue changes so that one does not reliably indicate the other, organisms may be lured into poor-quality habitat.
Ecological traps are thought to occur when the attractiveness of a habitat increases disproportionately in relation to its value for survival and reproduction. The result is preference of falsely attractive habitat and a general avoidance of high-quality but less-attractive habitats. For example, Indigo buntings typically nest in shrubby habitat or broken forest transitions between closed canopy forest and open field. Human activity can create 'sharper', more abrupt forest edges and buntings prefer to nest along these edges. However, these artificial sharp forest edges also concentrate the movement of predators which predate their nests. In this way, Buntings prefer to nest in highly altered habitats where their nest success is lowest.
While the demographic consequences of this type of maladaptive habitat selection behavior have been explored in the context of the sources and sinks, ecological traps are an inherently behavioral phenomenon of individuals. Despite being a behavioural mechanism, ecological traps can have far-reaching population consequences for species with large dispersal capabilities, such as the grizzly bear (Ursus arctos). The ecological trap concept was introduced in 1972 by Dwernychuk and Boag and the many studies that followed suggested that this trap phenomenon may be widespread because of anthropogenic habitat change.
As a corollary, novel environments may represent fitness opportunities that are unrecognized by native species if high-quality habitats lack the appropriate cues to encourage settlement; these are known as perceptual traps. Theoretical and empirical studies have shown that errors made in judging habitat quality can lead to population declines or extinction. Such mismatches are not limited to habitat selection, but may occur in any behavioral context (e.g. predator avoidance, mate selection, navigation, foraging site selection, etc.). Ecological traps are thus a subset of the broader phenomena of evolutionary traps.
As ecological trap theory developed, researchers have recognized that traps may operate on a variety of spatial and temporal scales which might also hinder their detection. For example, because a bird must select habitat on several scales (a habitat patch, an individual territory within that patch, as well as a nest site within the territory), traps may operate on any one of these scales. Similarly, traps may operate on a temporal scale so that an altered environment may appear to cause a trap in one stage of an organism's life, yet have positive effects on later life stages. As a result, there has been a great deal of uncertainty as to how common traps may be, despite widespread acceptance as a theoretical possibility. However, given the accelerated rate of ecological change driven by human land-use change, global warming, exotic species invasions, and changes in ecological communities resulting from species loss, ecological traps may be an increasing and highly underappreciated threat to biodiversity.
A 2006 review of the literature on ecological traps provides guidelines for demonstrating the existence of an ecological trap. A study must show a preference for one habitat over another (or equal preference) and that individuals selecting the preferred habitat (or equally preferred habitat) have lower fitness (i.e., experience lower survival or reproductive success). Since the publication of that paper which found only a few well-documented examples of ecological traps, interest in ecological and evolutionary traps has grown very rapidly and new empirical examples are being published at an accelerating rate. There are now roughly 30 examples of ecological traps affecting a broad diversity of taxa including birds, mammals, arthropods, fish and reptiles.
Because ecological and evolutionary traps are still very poorly understood phenomena, many questions about their proximate and ultimate causes as well as their ecological consequences remain unanswered. Are traps simply an inevitable consequence of the inability of evolution to anticipate novelty or react quickly to rapid environmental change? How common are traps? Do ecological traps necessarily lead to population declines or extinctions or is it possible that they may persist indefinitely? Under what ecological and evolutionary conditions should this occur? Are organisms with certain characteristics predisposed to being "trapped"? Is rapid environmental change necessary to trigger traps? Can global warming, pollution or exotic invasive species create traps? Embracing genetic and phylogenetic approaches may provide more robust answers to the above questions as well as providing deeper insight into the proximate and ultimate basis for maladaptation in general. Because ecological and evolutionary traps are predicted to add in concert with other sources of population decline, traps are an important research priority for conservation scientists. Given the rapid current rate of global environmental change, traps may be far more common than it is realized and it will be important to examine the proximate and ultimate causes of traps if management is to prevent or eliminate traps in the future.
Polarized light pollution
- ^ doi:10.1890/04-0913.
- ^ PMID 16761584.
- PMID 27677529.
- ^ doi:10.1139/z72-076.
- S2CID 2383356.
- PMID 21265448.
- S2CID 1345605.
- ISSN 0012-9658.
- ^ Horvath et al., in press as of Jan, 2013
- S2CID 25172917.
- Gilroy, J.J.; Sutherland, W.J. (2007). "Beyond ecological traps: perceptual errors and undervalued resources". Trends in Ecology and Evolution. 22 (7): 351–356. PMID 17416438.
- Horváth, Gábor; Kriska, György; Malik, Péter; Robertson, Bruce (2009). "Polarized light pollution: a new kind of ecological photopollution". Frontiers in Ecology and the Environment. 7 (6): 317–325. doi:10.1890/080129.
- Horváth, G; Zeil, J. (1996). "Kuwait oil lakes as insect traps". Nature. 379 (6563): 303–304. S2CID 4324524.
- Horváth, G; Bernáth, B; Molnár, G. (1998). "Dragonflies find crude oil visually more attractive than water: Multiple-choice experiments on dragonfly polarotaxis". Naturwissenschaften. 85 (6): 292–297. S2CID 12498964.
- Horváth, G; Malik, P; Kriska, G; Wildermuth, H. (2007). "Ecological traps for dragonflies in a cemetery: the attraction of Sympetrum species (Odonata: Libellulidae) by horizontally polarizing black gravestones". Freshwater Biology. 52 (9): 1700–1709.
- Kriska, G; Horváth, G; Andrikovics, S. (1998). "Why do mayflies lay their eggs en masse on dry asphalt roads? Water-imitating polarized light reflected from asphalt attracts Ephemeroptera". J Exp Biol. 201 (Pt 15): 2273–86. PMID 9662498.
- Kriska, G; Malik, P; Szivák, I; Horváth, G. (2008). "Glass buildings on river banks as "polarized light traps" for mass-swarming polarotactic caddis flies". Naturwissenschaften. 95 (5): 461–467. S2CID 40967738.
- Schwind, R. (1991). "Polarization vision in water insects and insects living on a moist substrate". J Comp Physiol A. 169 (5): 531–540. S2CID 39440345.
- Caswell, H. 2001. Matrix population models: Construction, analysis, and interpretation. 2nd edition. Sinauer. Sunderland, Mass., USA.
- Dias, P. C. (1996). "Sources and sinks in population biology". PMID 21237863.
- Diffendorfer, J. E. (1998). "Testing models of source-sink dynamics and balanced dispersal". JSTOR 3546763.
- Fretwell, S. D.; Lucas, H. L. Jr. (1969). "On territorial behavior and other factors influencing habitat distribution in birds". S2CID 83875137.
- Grinnell, J. (1917). "The Niche-Relationships of the California Thrasher". JSTOR 4072271.
- Holt, R. D. (1985). "Population-Dynamics in 2-Patch Environments — Some Anomalous Consequences of an Optimal Habitat Distribution".
- Howe, R. W.; Davis, G. J.; Mosca, V. (1991). "The Demographic Significance of Sink Populations".
- Hutchinson, G. E. (1957). "Concluding Remarks". Cold Spring Harb Symp Quant Biol. 22: 415–427.
- Johnson, D. M. (2004). "Source-sink dynamics in a temporally, heterogeneous environment". doi:10.1890/03-0508.
- Keddy, P. A. (1982). "Population Ecology on an Environmental Gradient — Cakile-Edentula on a Sand Dune". S2CID 7778352.
- Leibold, M. A.; Holyoak, M.; Chase, J. M.; Hoopes, M. F.; Holt, R. D.; Shurin, J. B.; Law, R.; Tilman, D.; Loreau, M.; et al. (2004). "The metacommunity concept: a framework for multi-scale community ecology".
- Pulliam, H. R. (1988). "Sources, sinks, and population regulation". S2CID 84423952.
- Pulliam, H. R.; Danielson, B. J. (1991). "Sources, Sinks, and Habitat Selection — a Landscape Perspective on Population-Dynamics" (PDF). S2CID 85125604. Archived from the original(PDF) on 26 March 2009. Retrieved 11 December 2010.
- Purcell, K. L.; Verner, J. (1998). "Density and reproductive success of California Towhees".
- Roberts, C. M. (1998). "Sources, sinks, and the design of marine reserve networks". Fisheries. 23 (7): 16–19. Archived from the original on 2012-04-04.
- Runge, J. P.; Runge, M. C.; Nichols, J. D. (2006). "The role of local populations within a landscape context:defining and classifying sources and sinks". S2CID 8952958.
- Thomas, C. D.; Singer, M. C.; Boughton, D. A. (1996). "Catastrophic extinction of population sources in a butterfly metapopulation". S2CID 85253063.
- Tittler, R.; Fahrig, L.; Villard, M. A. (2006). "Evidence of large-scale source-sink dynamics and long-distance dispersal among wood thrush populations". PMID 17249228.
- Watkinson, A. R.; Sutherland, W. J. (1995). "Sources, sinks and pseudo-sinks". JSTOR 5833.
- Williams, B. K., J. D. Nichols, and M. J. Conroy. 2001. Analysis and management of animal populations. Academic Press. San Diego, USA.