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Conserving the Endemic Birds of the Upper Guinea
Forest under Current and Future Climates
*Christopher Ilori and Deborah Ogunsola
University of Greenwich, UK and Apple Tree
International College, The Gambia
*Email for correspondence:
christopherilori@yahoo.co.uk
Abstract
That the World is currently experiencing biodiversity
loss as a result of land-use and climate change is no
longer a debate. These changes, whether in isolation or
in combination, will have an impact on the distributions
of species. Given this, it is becoming increasingly
important to assess the distributions of species across
landscapes. This study aims to produce habitat
suitability maps for current and future distributions of
the endemic bird species in the Upper Guinea forest of
West Africa using GIS and a predictive species
distribution model. For current distributions, data
spanning 50 years (1950 – 2000) were obtained from
WorldClim’s data portal. Models were developed for
future distributions from the Intergovernmental Panel
for Climate Change’s HadCM3 climate model for 2 time
steps (2020 and 2050). Environmental layers were also
used to examine the effects of different relevant
predictors. The study revealed that vegetation was the
most important determining variable for bird
distributions in the Upper Guinea forest. It was also
found that precipitation-based variables played more
significant role than temperature-based variables for
most of the modelled species. Realized and fundamental
niches can be identified for species relocation to
minimise biodiversity loss. Human disturbances will
continue to lead to the destruction of vegetation cover,
which currently serves as the major distribution
determinant for the majority of the bird species, future
modelling should therefore be enhanced by including
vegetation projection.
Keywords: Species distribution model, Upper Guinea
forest, biodiversity loss, species relocation, climate
model
Understanding the variation of tree growth in an
African mountain forest
Badru Mugerwa 1 *, Douglas Sheil 1, 2,3 and Julius Bunny
Lejju 4
1 Institute of Tropical Forest Conservation, Mbarara University
of Science and Technology, P.O. Box 44, Kabale, Uganda
2 School of Environment, Science and Engineering, Southern
Cross University, P.O. Box 157, Lismore NSW 2480, Australia.
3
Centre for International Forestry Research, P.O. Box 0113
BOCBD, Bogor 16000, Indonesia
4 Department of Biology, Mbarara University of Science and
Technology, P.O. Box 1410 Mbarara, Uganda
*Email for correspondence:mugerwa@itfc.org or
b.mugerwa@gmail.com
Abstract
A strong negative relationship between climate change and
tropical forest growth has been reported. However, models
for predicting the responses of tropical forests’ growth to
climatic changes rarely consider the relationships between
the local site characteristics and tree growth. We examined
the variation of tree growth rates in Bwindi Impenetrable
National Park. We attempted to understand and explain
the relationships between tree growth and thirteen
site/tree characteristics. We used a three-year growth data
set for 3067 trees and tree ferns belonging to 99 species
from six 1-ha permanent sample plots (PSPs). All stems
measured ≥10 cm diameter at breast height. Tree growth
rates varied significantly among PSPs. Average tree growth
rate was 0.29cm/yr. Single factor general linear models
(GLM) with a Gaussian error distribution and identity link
identified species as the best predictor of tree growth
among the considered predictor variables. A significant
positive variation of tree growth among species, tree size
classes, slope position, crown form, crown position, climber
infestation and tree diameter was observed. On the other
hand, tree growth varied significantly negatively with forest
undergrowth, past human disturbance, competition for
light, competition for all growth resources and altitude.
Surprisingly, tree growth did not show a significant
relationship with tree basal area. GLMs further
demonstrated that a significant negative interaction
between species, competition for light and altitude best
explained variation of tree growth. This means that as
altitude increases, competition for light also increases
leading to reduced tree growth. Tree growth rates were
significantly associated with both tree and local site
characteristics. Our results suggest that these should be
considered in managing tropical rainforest’s growth to
mitigate climate change impacts through REDD+ and other
mechanisms. Local tree/site characteristics should also be
incorporated in models for predicting the responses of
tropical forests to climatic changes.
Keywords: Bwindi, climate change, forest productivity,
REDD+, tree growth, local forest and site characteristics.
TAAG First African Student’s Conference, Nairobi. 2-4 July, 2013 17