Abstract:
Amphibians are sensitive to changes in the environment and are, therefore, excellent
indicators of success in restoring degraded habitats. As such, a clear understanding on how
amphibian populations respond to changes in the environment is required. In order for
conservationists to establish if the declining trends are changing, biodiversity recovery studies
are essential especially in reclaimed habitats. This study focused on the recovery of
amphibians, particularly on frogs, in reclaimed quarries of the Bamburi Cement Plant near
Mombasa whereby the diversity, species abundances and composition at different stages of
quarry re-establishment were assessed.
The study area was divided into three zones based on the 13-year interval since the
beginning of the rehabilitation process. Transect surveys and time-constrained search and size
method were used for sampling 20 randomly selected sites. Sampling was done during the
rainy and the dry seasons, with searches conducted between 900 and 1,600 hours during the
day and between 1,800 to 2,100 hours at night. Recording of basic morphological data of
collected specimens was done in the field to aid in grouping specimens before voucher
materials were preserved in 10% formalin and stored in 70% alcohol. Further identifications
and confirmations matching specimens to species were carried out using specialized
classification keys from the National Museum of Kenya.
Twelve species were encountered across the three zones, with Ptychadena anchietae
and Phrynobatrachus acridoides, respectively, the most abundant. It was also noted that
amphibian diversity across the quarries was independent of the age of ecological re-
establishment (r = -0.5). This is indicated by the higher amphibian diversity in the south and
north quarries (N = 1050 and 506 respectively) despite their relatively younger age since re-
establishment compared to the central quarry (N = 438). Lower diversity in the central quarry,
although the oldest, may be largely attributed to human disturbance. Additionally, exotic
plantations across the study area are poor in species since they are monocultures and, thus, not
heterogeneous enough to support higher anuran diversity. Since amphibians act as one of the
best measure of environmental health, rehabilitation process in the quarries need to embrace
mechanisms that support maximum biodiversity recovery such as replanting of more
indigenous tree species as opposed to only exotic monocultures.
