Long-term population monitoring of the Critically Endangered Grenada Dove (Leptotila wellsi) on Grenada, West Indies

Bonnie L. Rusk

Abstract


Abstract The Grenada Dove (Leptotila wellsi) is an IUCN-listed Critically Endangered species endemic to the island of Grenada, West Indies. Long-term population monitoring was carried out episodically between 1987 and 2007 using territory (spot) map­ping. Changes in distribution were also noted through 2016. The most recent population estimate of 136 individuals is based on territorial mapping of 68 males (assuming a 1:1 sex ratio) in 2007, representing a 25% decline from 182 individuals estimated immediately prior to Hurricane Ivan in 2003–2004. The species is limited almost exclusively to two areas in the southwest and on the west coast, with only a few individuals found outside these areas. Major threats include habitat loss and degradation due to residential and commercial development, small-scale agriculture, and fire. The impacts of these threats have been compound­ed by the impacts of extreme weather events such as Hurricane Ivan in 2004, and a high incidence of introduced mammalian predators.

Keywords abundance, endangered, endemic, Grenada Dove, Leptotila wellsi

 

Resumen Monitoreo poblacional a largo plazo de la En Peligro Crítico Paloma de Granada (Leptotila wellsi) en Granada, Caribe Insular—La Paloma de Granada (Leptotila wellsi) es catalogada por la UICN como una especie endémica y En Peligro Crítico en la isla de Granada, en el Caribe Insular. El monitoreo a largo plazo de la población se llevó a cabo de forma episódica entre 1987 y 2007 utilizando el mapeo de territorios (sitios). También se observaron los cambios en la distribución a lo largo de 2016. El esti­mado poblacional más reciente de 136 individuos está basado en el mapeo territorial de 68 machos (asumiendo una proporción de sexos de 1:1) en 2007, lo que representa una disminución del 25% de los 182 individuos estimados inmediatamente antes del huracán Iván en 2003–2004. La especie está limitada casi exclusivamente a dos áreas en el suroeste y la costa oeste, con sólo unos pocos individuos fuera de las mismas. Las principales amenazas incluyen la pérdida y degradación del hábitat para el desa­rrollo urbanístico y comercial, la agricultura a pequeña escala y el fuego. Los efectos de estas amenazas han sido agravados por los impactos de eventos climáticos extremos como el huracán Iván en 2004 y una alta incidencia de mamíferos depredadores.

Palabras clave abundancia, amenazada, endémica, Leptotila wellsi, Paloma de Granada

 

Résumé Surveillance à long terme de la population de la Colombe de Grenade (Leptotila wellsi) En danger critique sur Gre­nade, Antilles—La Colombe de Grenade (Leptotila wellsi) est une espèce endémique à Grenade, dans les Antilles, étiqueté En danger critique par l’UICN. Une étude à long terme de la population a été effectuée épisodiquement entre 1987 et 2007 en utili­sant la cartographie de territoire par secteur. Les changements dans la distribution de la colombe ont également été observés en 2016. L’estimation de la population la plus récente de 136 individus est basée sur une cartographie territoriale de 68 mâles (en supposant un ratio sexuel de 1 : 1) en 2007, ce qui représente une baisse de 25% par rapport à les 182 individus estimés im­médiatement avant l’ouragan Ivan en 2003-2004. L’espèce est limitée presque exclusivement à deux zones dans le sud-ouest et sur la côte ouest de Grenade, avec seulement quelques individus trouvés en dehors de ces zones. Les menaces principales com­prennent la perte et la dégradation de l’habitat pour le développement résidentiel et commercial, l’agriculture à petite échelle, et le feu. Les effets de ces menaces ont été aggravés par les impacts des calamités météorologiques tels que l’ouragan Ivan en 2004 et une forte incidence de mammifères prédateurs introduits.

Mots clés abondance, Colombe de Grenade, en danger, endémique, Leptotila wellsi


Keywords


Abundance; Endangered; Endemic; Grenada Dove; Leptotila wellsi

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