Background: Species diversity is an important indicator of
ecosystem productivity and trophic structure. The distribution of birds in
different habitats depends largely on the availability of critical resources.
Birds contribute substantially to the overall species richness of West African
forests, currently recognised as biodiversity hotspots of global importance.
Birds mirror changes in other biodiversity (for example, other animals and
plants) and are highly responsive and sensitive to environmental change, making
them very useful in studies designed to address the effects of human and other
environmental disturbances on community stability and productivity.
Aim: The study assessed the abundance and diversity of
sunbird species at Ngel Nyaki forest reserve, Taraba State, Nigeria. during and
after peak periods of flowering of key bird-visited tree species.
Methods: The study was conducted at Ngel Nyaki Forest
Reserve. The line transect method was used to assess sunbird species abundance
and distribution. A pair of Nikon binoculars (8 x 10) was used to confirm the
identity of birds located by eye. Mist-nets placed strategically in places of
high abundance and diversity of floral resources were used to capture and
identify sunbird species that eluded observers during focal observations.
Nineteen (19) transects cutting across two distinct habitat classes were used
to record the abundance and diversity of sunbird species. Data were analysed
using SPSS version 15.0 (2013) and Excel. Specific analyses include: An
Independent sample T-test was used to compare the differences in diversity
between the two habitat classes.
Results: A total of 3,035 individuals from 11 species, drawn
from 8 genera in the Nectrinidae family, were sighted and recorded during 1680
minutes (28 hrs) of focal observation. Sixteen (16) Afro-tropical tree species
were sampled for interactions between sunbird species and their floral
resources. Ninety-nine (99) individuals of 8 sunbird species were captured
after about 209 hours and 4 minutes of trapping. Bird traps revealed three
species that were not seen during focal observations. Results indicated that
the reserve accounts for about 46.2 % of the total species of sunbirds in
Nigeria and about 36.4% in the West African sub-region. The distribution and
relative abundance of C. venustrus at the edge compared to the fragment may
also be an indication of its sensitivity and vulnerability to fragmented
landscapes such as the riparian fragments of Ngel Nyaki.
Conclusion: Although a greater total number of individual
sunbirds of various species were sighted in the Core forest than in the
riparian fragments, sunbird species diversity did not differ significantly
between the two habitat classes. Floral
resources and flowering phenology appear to be major drivers in the
distribution and abundance of sunbird species at Ngel Nyaki Forest Reserve.
Author(s) Details
Charles Ayuk Nsor
Department of Biological Sciences, Gombe State University, Gombe, Nigeria.
Hazel M. Chapman
School of Biological Sciences, University of Canterbury, Christchurch, New
Zealand.
William Godsoe
Bio-Protection Centre, Lincoln University, Lincoln, New Zealand.
Amina Haruna Aliyu
Department of Biological Sciences, Gombe State University, Gombe, Nigeria.
Please see the book here:- https://doi.org/10.9734/bpi/rpbs/v6/5936
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