Spatial variation in plant species richness and diversity along human disturbance and environmental gradients in a tropical wetland
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Date
2014-11
Authors
Journal Title
Journal ISSN
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Publisher
Springer Science+Business Media Dordrecht 2014
Abstract
Human disturbance, natural environmen-
tal conditions and seed dispersal are often inferred as
important drivers of plant community richness and
diversity in wetland ecosystems. However, plant
functional groups within a plant community have
different environmental requirements and may
respond differently to human disturbance. Therefore,
the understanding of the relative importance of these
variables in determining community and functional
groups richness and diversity is important for
improved management and wise use of wetland
resources. We collected data on vegetation and envi-
ronmental conditions, human disturbance and seed
dispersal from 60 plots of 20 9 50 m, to identify
variables that potentially affect total species richness
and Shannon-Wiener diversity of the grassland plant
community at the Kilombero Valley wetland, Tanza-
nia. We further tested whether important predictor
variables for species richness and Shannon-Wiener
diversity differ among graminoid, forb and shrub
functional groups. Overall, our results suggest that environmental conditions, human disturbance and seed
dispersal determine spatial variation in species rich-
ness and Shannon-Wiener diversity of the grassland
vegetation. The total richness and Shannon-Wiener
diversity and the richness of shrubs decreased with
distance from the Kilombero River, whereas the total
Shannon-Wiener diversity and the Shannon-Wiener
diversity of graminoids decreased with the increase in
grazing intensity. Shrub species richness was related to
the spatial position of plots and decreased with total
organic carbon of soil. Current increase in human
disturbances through cattle husbandry and changes in
natural environmental conditions (e.g. through water
diversion and drainage) should be discouraged in order
to restore and sustain biodiversity of the Kilombero
wetland.
Description
Wetlands Ecology and Management, 2015; 23:395–404
Keywords
Plant functional groups, Wetland grasslands, Anthropogenic disturbance, Shannon index, Kilombero, Tanzania