Indication of a species in an extinction vortex: The ocellated turkey on the Yucatan peninsula, Mexico

TY - JOUR

T1 - Indication of a species in an extinction vortex: The ocellated turkey on the Yucatan peninsula, Mexico

AU - Kampichler, C.

AU - Calmé, S.

AU - Weissenberger, H.

AU - Arriaga-Weiss, S.

N1 - Reporting year: 2010

PY - 2010

Y1 - 2010

N2 - The ocellated turkey Meleagris ocellata (OT) is a large, unmistakable endemic bird of the Yucatan peninsula. The species has suffered a considerable loss of distributional area as well as local abundance between 1980 and 2000 and is classified as endangered according to Mexican norms. We applied Classification Trees and Random Forests in order to determine the factors that most closely explain the observed patterns of distribution and abundance loss, and to develop hypotheses that may guide measures for the protection of the OT. Among the most important predictors of change were variables corresponding to aspects of forest cover and variables on human population and small settlements. OT abundance in 1980, however, was by far the most important predictor for OT abundance change. This is an indication that the OT dynamics are governed by internal rather than by external factors. Medium and low abundances in 1980 inevitably led to a further decrease during the following years, which gives rise to the conclusion that the OT might find itself in an extinction vortex. We suggest the following hypothetical scenario for OT decline: migrant people from other Mexican states colonise forested regions in Yucatan; they establish small settlements; bushmeat hunting is important for their survival; the naïve OT is easy prey; huntingdtogether with beginning deforestationdreaches a certain level, and local OT abundance falls below a critical threshold; OT continues declining regardless of current social and environmental changes except where there is total protection of both the species and its habitat.

AB - The ocellated turkey Meleagris ocellata (OT) is a large, unmistakable endemic bird of the Yucatan peninsula. The species has suffered a considerable loss of distributional area as well as local abundance between 1980 and 2000 and is classified as endangered according to Mexican norms. We applied Classification Trees and Random Forests in order to determine the factors that most closely explain the observed patterns of distribution and abundance loss, and to develop hypotheses that may guide measures for the protection of the OT. Among the most important predictors of change were variables corresponding to aspects of forest cover and variables on human population and small settlements. OT abundance in 1980, however, was by far the most important predictor for OT abundance change. This is an indication that the OT dynamics are governed by internal rather than by external factors. Medium and low abundances in 1980 inevitably led to a further decrease during the following years, which gives rise to the conclusion that the OT might find itself in an extinction vortex. We suggest the following hypothetical scenario for OT decline: migrant people from other Mexican states colonise forested regions in Yucatan; they establish small settlements; bushmeat hunting is important for their survival; the naïve OT is easy prey; huntingdtogether with beginning deforestationdreaches a certain level, and local OT abundance falls below a critical threshold; OT continues declining regardless of current social and environmental changes except where there is total protection of both the species and its habitat.

U2 - 10.1016/j.actao.2010.08.004

DO - 10.1016/j.actao.2010.08.004

M3 - Article

SN - 1146-609X

VL - 36

SP - 561

EP - 568

JO - Acta Oecologica

JF - Acta Oecologica

IS - 6

ER -