A Recovery Program for the Natterjack Toad (Bufo calamita) in Britain

Conservation Biology - Tập 11 Số 6 - Trang 1329-1338 - 1997
Jonathan S. Denton1, Susan P. Hitchings1, Trevor J. C. Beebee1, Antony Gent2
1School of Biology, University of Sussex, Falmer, Brighton, BN1 9QG, United Kingdom
2English Nature, Northminster House, Peterborough PE1 1UA, United Kingdom

Tóm tắt

The natterjack toad (  Bufo calamita) is an endangered species in Britain and has been legally protected since 1975. This amphibian suffered a major decline during the first half of the twentieth century, due partly to habitat destruction but mostly to successional changes in its specialized biotopes and anthropogenic acidification of breeding sites. In addition to site and species protection, extensive autecological research over the past 25 years has provided the foundations for an intensive, 3‐year species recovery program funded by the statutory nature conservation organizations (English Nature and the Countryside Council for Wales). This program was based on habitat management and reintroductions to restored sites and followed similar but less intensive efforts. Management of heath and dune habitats focused on restoration and maintenance of early stages of seral succession, initially through physical clearance of invasive scrub and woodland vegetation and later by the reestablishment of grazing regimes similar to those prevalent in earlier centuries. In some cases extra breeding pools were provided to either increase or stabilize natterjack toad populations that had become reliant on one or very few pools at small sites or to promote range expansion within large habitat areas. By 1995 proactive conservation work had been carried out at 29 (69%) of the 39 sites with extant native populations, including 8 during the recovery program. Twenty reintroductions also had been attempted, including nine during the program. At least six reintroductions resulted in the foundation of expanding new populations, and an additional eight have shown initial signs of success. Conservation methods developed for Bufo calamita should provide a useful precedent for long‐term conservation of early successional habitats and species.Programa de Recuperación para el Sapo Natterjack (Bufo calamita) en Gran BretañaEl sapo Natterjack (Bufo calamita) es una especie en peligro de extinción en Gran Bretaña y esta sujeto a protección desde 1975. Este anfibio sufrió una declinación importante durante la primera mitad del siglo veinte, debido en parte a la destrucción del hábitat pero principalmente a los cambios sucesionales en sus biotopos y a la acidificación antropogénica de sitios de reproducción. Además de la protección de sitios y de la especie, extensas investigaciones autoecológicas en los últimos 25 años proporcionaron las bases para un programa intensivo de recuperación patrocinado por las organizaciones de conservación de naturaleza estatutarias (English Nature y Countryside Council for Wales). Este programa se basó en el manejo del hábitat y reintroducciones en sitios restaurados, como continuación de esfuerzos similares pero menos intensivos. El manejo de brezales y dunas se enfocó en la restauración y mantenimiento de las primeras etapas sucesionales, se inició con la remoción de hierbas y vegetación leñosa invasoras y posteriormente se restablecieron regímenes de pastoreo similares a los prevalecientes en siglos anteriores. En algunos casos se proporcionaron charcas para reproducción para incrementar o estabilizar las poblaciones o para promover la expansión del rango en áreas con hábitats extensos. Para 1995 el trabajo de conservación se había desarrollado en 29 (69%) de los 39 sitios con poblaciones nativas, incluyendo 8 durante el programa de recuperación. También se habían intentado veinte reintroducciones, incluyendo 9 durante el programa. Por lo menos 6 reintroducciones resultaron en la fundación de nuevas poblaciones y 8 más han mostrado señas iniciales de éxito. Los métodos de conservación desarrollados para Bufo calamita deben constituir un precedente útil para la conservación a largo plazo de hábitats en sucesión inicial y de especies.

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Conservation Biology

Tập 11 Số 6

1329-1338

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