Effects of Karst Forest Degradation on Pulmonate and Prosobranch Land Snail Communities in Sabah, Malaysian Borneo

Authors

  • MENNO SCHILTHUIZEN,

    Corresponding author
    1. Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Locked Bag 2073, 88999 Kota Kinabalu, Malaysia
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  • THOR-SENG LIEW,

    1. Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Locked Bag 2073, 88999 Kota Kinabalu, Malaysia
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  • BERJAYA BIN ELAHAN,

    1. Kinabatangan Orang-utan Conservation Project, P.O. Box 3109, 90734 Sandakan, Malaysia
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  • ISABELLE LACKMAN-ANCRENAZ

    1. Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Locked Bag 2073, 88999 Kota Kinabalu, Malaysia
    2. Kinabatangan Orang-utan Conservation Project, P.O. Box 3109, 90734 Sandakan, Malaysia
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‡ email schilthuizen@yahoo.com, crawlies@ums.edu.my

Abstract

Abstract: Limestone (karst) outcrops in Southeast Asia are rich in land snails. Certain groups of land snails, in particular Prosobranchia species, are restricted to limestone and show a high degree of short-range endemism. Karst habitats are, however, seriously degraded by quarrying, logging, agriculture, and burning. The effect of these disturbances on land snail fauna is unknown, so we studied paired primary and secondary forest localities on six separate limestone hills in Sabah, Malaysian Borneo. Land snails were sampled with a standard protocol and identified to species level. More than 16,000 individuals, belonging to 74 species, were recorded. In most sites, snail diversities did not differ between disturbed and undisturbed plots. However, pulmonate snails were significantly more abundant at disturbed localities than prosobranch snails, whereas abundances for both groups were similar at undisturbed sites. Because Prosobranchia contain many site-endemic species, our findings suggest that continued exposure to these disturbances will eventually lead to extinctions in this group.

Abstract

Resumen: Los afloramientos de roca caliza (karst) en el sureste de Asia son ricos en caracoles terrestres. Ciertos grupos de caracoles terrestres, particularmente especies de Prosobranchia, están restringidos a calizas y muestran un alto grado de endemismo de distribución corta. Sin embargo los hábitats karst están seriamente degradados por la explotación de canteras, la extracción de madera, la agricultura e incendios. Se desconoce el efecto de estas perturbaciones sobre la fauna de caracoles terrestres, así que estudiamos localidades pareadas de bosque primario y secundario en seis colinas separadas en Sabah, Malasia. Los caracoles fueron muestreados con un protocolo estándar e identificados a nivel de especie. Registramos más de 16,000 individuos, pertenecientes a 74 especies. En la mayoría de los sitios, la diversidad de caracoles no fue diferente en las parcelas perturbadas y no perturbadas. Sin embargo, los caracoles pulmonados fueron significativamente más abundantes que los caracoles prosobranquios en localidades perturbadas, mientras que las abundancias de ambos grupos fueron similares en sitios no perturbados. Lo anterior sugiere que la exposición continua a estas perturbaciones conducirá eventualmente a extinciones en Prosobranchia, debido a que contiene muchas especies endémicas.

Ancillary