Perceptual trap

In a 2004 article discussing source–sink dynamics, James Battin did not distinguish between high-quality habitats that are preferred or avoided, labelling both "sources."[2] The latter scenario, in which a high-quality habitat is avoided, was first recognised as an important phenomenon in 2007 by Gilroy and Sutherland,[3] who described them as "undervalued resources." The term "perceptual trap" was first proposed by Michael Patten and Jeffrey Kelly in a 2010 article.[1] Hans Van Dyck[4] argues that the term is misleading because perception is also a major component in other cases of trapping.

Animals use discrete environmental cues to select habitat.[5] A perceptual trap occurs if change in an environmental cue leads an organism to avoid a high-quality habitat.[1] It differs, therefore, from simple habitat avoidance, which may be a correct decision given the habitat's quality.[1] The concept of a perceptual trap is related to that of an ecological trap, in which environmental change causes preference towards a low-quality habitat.[1] There is expected to be strong natural selection against ecological traps, but not necessarily against perceptual traps, as Allee effects may restrict a population’s ability to establish itself.[1]

Patten and Kelly[1] propose that a perceptual trap is acting on populations of the lesser prairie chicken

To support the concept of a perceptual trap, Patten and Kelly[1] cited a study of the lesser prairie chicken (Tympanuchus pallidicinctus). The species' natural environment, shinnery oak grassland, is often treated with the herbicide tebuthiuron to increase grass cover for cattle grazing.[1] Herbicide treatment resulted in less shrub cover, a habitat cue that caused female lesser prairie-chickens to avoid the habitat in favour of untreated areas. However, females who nested in herbicide-treated areas achieved comparable nesting successes and clutch sizes to those in untreated areas.[1] Patten and Kelly suggest that the adverse effects of tebuthiuron treatment on nesting success are countered by various effects, such as greater nest concealment through increased grass cover.[1] Therefore, female birds are erroneously avoiding a high-quality habitat. Patten and Kelly[1] also cited as a possible perceptual trap the cases of the spotted towhee (Pipilo maculatus) and rufous-crowned sparrow (Aimophila ruficeps), which tend to avoid habitat fragments, even though birds nesting in habitat fragments achieve increased nesting success due to a reduction in snake predation.[6]

• Source–sink dynamics
• Ecological trap
• Type I and type II errors