Human-Altered Tree-Based Habitats and Their Value in Conserving Bird and Bat Diversity in Northeast Luzon, The Philippines

Abstract

This chapter discusses the conservation value of smallholder tree-based systems for bird and bat species in the human-altered landscape of the Cagayan Valley, Northeast Luzon. Birds and bats in village homegardens, small Gmelina arborea plantations and uncultivated shrub-land were surveyed in 11 localities, using 118 point counts for birds and 34 mist-net-lines for bats. A total of 1,093 individual birds were observed representing 58 resident bird species, including 11 species endemic to the Philippines, 15 forest bird species and one globally threatened species. A total of 409 bats were captured belonging to 16 species, including five endemics, five forest bat species and also one globally threatened species. Gmelina forest plantations held slightly more forest bird species than homegardens and surrounding shrub-land. However, the human-altered landscape fails to serve as an alternative for closed-canopy forest habitat containing only 13 percent of lowland forest birds, 15 percent of endemic lowland birds and eight percent of threatened lowland birds known to occur in the region. For bats, human-altered habitats offer slightly better conditions, containing 44 percent of all lowland bats, 42 percent of endemic bats and 29 percent of forest bats in the region. Most forest birds and bats were restricted to a narrow zone bordering contiguous forest. Reforestation through mono-culture Gmelina arborea plantations is of little direct value to bird and bat conservation but it could act as a catalyst for forest recovery. Better structured, diverse and interconnected homegardens and forest plantations potentially have higher conservation values for birds and bats.