Puerto Rican Parrots and Potential Limitations of the Metapopulation Approach to Species Conservation

Abstract

Population viability analyses for a number of endangered species have incorporated a metapopulation approach. The risk assessments of these viability analyses have indicated that some extant populations should be subdivided into numerous subgroups with exchange of individuals among them in order to

Allee effect, sexual selection and demographic stochasticity

“…Many examples of this phenomenon have been reported in the literature (e.g. Brock and White 1992, Cox et al 1993, Wilson et al 1994, Kummer 1995.…”

“…Furthermore, island species tend to be threatened and go extinct more often than mainland species (King 1978, Temple 1986, Collar et al 1994. Threatened island endemics such as the Puerto Rican parrot and the Mauritius kestrel show important signs of reproductive depression in the absence of free mate choice (Jones et al 1991, Brock and White 1992, Anonymous 1994, Wilson et al 1994). This observation suggests that the intensity of sexual selection even in these cases is sufficiently large to severely affect reproductive decisions by females.…”

“…For example, Puerto Rican parrots, Amazona 6ittata (Brock and White 1992, Anonymous 1994, Wilson et al 1994, and California condors, Gymnogyps californianus (Cox et al 1993), reproduce at a higher rate when given free choice of a mate. Similarly, in the threatened Mauritius kestrel, Falco punctatus, eggs collected from free-breeding pairs had higher hatchability than eggs collected from pairs breeding in captivity (Jones et al 1991).…”

Conspecifics can be aliens too: A review of effects of restocking practices in vertebrates

“…Hess (1996) also suggested that restocking may facilitate the spread of infectious disease between subpopulations, and may thus increase the probability of metapopulation extinction and reduce patch occupancy. For this reason, the planned subdivision of a population of endangered Puerto Rican parrots (Amazona vittata BODDAERT) was criticised (Wilson et al 1994).…”

Avian studies and research opportunities in the Luquillo Experimental Forest: A tropical rain forest in Puerto Rico

“…We find it noteworthy, however, that exotic bird species, especially psittacines common in the rural and suburban communities along the forest boundary, have yet to colonize the forest. Exotic bird species in the developed areas bordering the LEF might serve as a reservoir for diseases for forest birds, such as the parrot (for disease risk see Wilson et al, 1994). However, this possibility has not been studied.…”