Human-Altered Tree-Based Habitats and Their Value in Conserving Bird and Bat Diversity in Northeast Luzon, The Philippines - Smallholder Tree Growing for Rural Development and Environmental Services - page 333

16.1 Introduction

Traditionally, ecologists and conservationists have focused their attention on wil-
derness areas, such as large undisturbed protected forest areas, in their attempt to
conserve tropical biodiversity (Bruner et al. 2001). However, while deforestation
continues, there is concern that the remaining forest areas will not be large enough
to conserve the original tropical forest species diversity (O'Riordan and Stoll-
Kleeman 2002).
Consequently, more attention has been given in recent years to the role of
human-altered landscapes and off-park conservation in sustaining tropical biodiver-
sity (Hughes et al. 2002; Petit and Petit 2003; McNeely 2004; Atta-Krah et al.
2004; McNeely and Schroth 2006). Agroforestry and other tree-based land use
systems are considered highly relevant within this context as they may offer a suit-
able habitat for a range of forest species (McNeely and Schroth 2006). Moreover,
these systems also provide economic benefits in terms of local livelihoods and
farmers' income, and environmental services such as watershed protection and car-
bon sequestration. The integrated ecosystem approach advocated by the Convention
on Biological Diversity seeks such combinations of rural development and the con-
servation of ecosystem services and biodiversity (Garrity 2004; McNeely 2004;
McNeely and Schroth 2006).
Within a Southeast Asian context, relatively few studies have been published on
biodiversity in human-altered landscapes (Peh et al. 2006) though recently a
number of studies compare forest bird species richness between various agro-
ecosystems and natural forest (Thiollay 1995; Waltert et al. 2004; Peh et al. 2005,
2006; Sodhi et al. 2005; Marsden et al. 2006; Round et al. 2006). To our knowledge
no study has yet been published on birds and bats in agro-ecosystems in the
Philippines.

16.1.1 Deforestation and Threatened Biodiversity in the Philippines

The Philippines has lost most of its original forest since 1900 (Kummer 1992). The
current forest cover (FAO 2007) is 71,620 km 2 (24 percent of land area) with an
annual deforestation rate of 2.1 percent in the period 2000-2005 (see also Chapter
1, this volume). Geographic isolation and specific local circumstances drove a proc-
ess of local evolution which resulted in large numbers of endemic species restricted
to islands and island groups in the Philippines (Heaney 1986). Of the world's plant
and vertebrate species, 1.9 percent is endemic to (one of) the 7,100 islands of the
Philippines (Myers et al. 2000). Endemism levels within the Philippines vary from
31 percent of all bird species (Kennedy et al. 2000) to 78 percent of currently
known amphibian species (IUCN and Conservation International and NatureServe
2006). As Philippine endemic species primarily evolved in forest they are consid-
ered to be forest specialists and as such vulnerable to deforestation. The loss of origi-
nal habitat, in combination with the high proportion of global biodiversity restricted