4 
Bulletin ofihcHANHS 29(3) 
ARTICLES 
ECOLOGICAL MONITORING: ITS 
IMPORTANCE FOR THE 
CONSERVATION OF BIOLOGICAL 
DIVERSITY IN THE EASTERN ARC 
FORESTS 
The Eastern Arc forests of Tanzania have been classified 
as one ol the 14 most threatened tropical forest hotspots 
worldwide because of their unusual concentrations of 
endemic species and the significant threats facing them 
(Myers 1990. 1991) The purpose of this paper is to 
briefly highlight the useful role that ecological 
monitoring can play as part ol a broader program ol 
activities to conserve biological diversity and to discuss 
current and planned ecological monitoring activities in 
the liasl II samba ras 
INTRODUCTION 
The Eastern Are Mountains (Figure I) arc. for their 
M/e. the richest site biologically in Tanzania Although 
the closed forests ol the Eastern Are Mountains cover 
less Ilian 2% (1.81X1 sq km) ol the land surface of 
i 
KENYA 
mainland Tanzania, these lorests contain approximately 
18% of all plants. 43* of all butterflies. 22* of all 
amphibians and reptiles, 26* of all birds, and 24* of 
all mammals found in mainland Tanzania (N'ewmark 
in prep ) Possibly even more importantly, these forests 
contain one of the highest proportions ol endemic 
species of any region in A Inca Approximately 25% 
of plant species. 82% of linyphiid spider species, 39% 
of butterflies species. 66% ot herpetofauna species. 
28% of montane bird species, and 7% of mammals 
species are endemic to the Eastern Arc mountains 
(Ncwmark in prep > Furthermore, the Eastern Arc 
forests contain the majority of the globally endangered, 
vulnerable, and rare mammal and bird species and 
subspecies found ;n mainland Tanzania (Ncwmark, in 
prep ) 
As a result of their unusual diversity and endemism, 
there has been considerable interest both nationally and 
internationally in conserving the biological diversity 
of the Eastern Are Mountains A number of projects 
have been implemented (c.g.. East Usambara Forest 
Catchment Project. East Usambara Agriculture and 
Conservation Projects, and proposed Ambangulu 
Conservation Project) and protected areas (e g . 
Udzungwa National Park and proposed Amani Nature 
Reserve) established in the last 10 years to conserve 
biological diversity in the Eastern Arc forests The long- 
term success of these projects and protected areas is 
dependent upon reducing human pressures upon the 
forests, increasing the effectiveness of forest manage- 
ment. and developing a more complete 
understanding of the ecological 
dynamics of these forests. Ecological 
monitoring is central to particularly 
p w these latter two requirements 
Ai/wni'iM " 1 
TANZANIA 
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North Parc f 
South P.irc^^ 
Wc*l Uutmhura 
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MAFIA 
The Eastern Arc Mountains of Tanzania and Kenya (Ml Kilimanjaro is 
not on eastern Arc Mountian) ( from Cordeiro, in press) 
BROAD-SCALE STRATEGIES 
FOR CONSERVING 
BIOLOGICAL DIVERSITY 
Biological diversity is the natural 
variation in genes, populations, species, 
communities, cco-systems. and 
landscapes (Wilson 1988) This 
variation changes both through space 
and time In addition, this variation is 
a result of the interaction of organisms 
with their environment of which such 
ecological and evolutionary processes 
as predation, competition, nutricni 
cycling, energy flows, succession, 
pollination, disturbance, dispersal, and 
movement are particularly important 
Thus the conservation of biological 
diversity requires not only conserving 
the spatial and temporal dimensions of 
biological diversity but also maintaining 
the ecological and evolutionary 
processes upon which this natural 
variation is dependent. 
