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 347

castaneiceps occurred in all three habitat types, with the highest density in
Gmelina forest. Two endemic open area species were recorded: threatened Anas
luzonica in shrub-land (one record only) and Amaurornis olivaceus in shrub-land
and Gmelina forest.
Shrub-land had the highest bat species richness (12 species). Gmelina forest and
homegardens had nine bat species each. Although only 44 percent of all bat species
mist-netted were fruit bats, in terms of individuals the vast majority (93 percent)
belonged to this family. Shrub-land had the highest number of Microchiroptera spe-
cies (seven) and of forest bat species (three). Homegardens and Gmelina forest had
respectively two and one forest bat species. Three (33 percent) cave roosting bat
species were recorded for Gmelina forest and four (44 percent) and eight (67 per-
cent) species for homegardens and shrub-land respectively. Gmelina forest and
homegardens shared 67 percent of all bat species and 83 percent of fruit bats
(Sørensen similarity indices), whereas Gmelina forest and shrub-land shared 67
percent of all bats and 73 percent of fruit bats. Homegardens and shrub-land only
shared 57 percent of all bat species but were very similar in fruit bat species com-
position (91 percent species shared).
The most common bat species in both Gmelina forest and homegardens was
Cynopterus brachyotis with 0.513 and 0.937 captures per net-night respectively.
This species was less common in shrub-land (0.231 captures per net-night);
Rousettus amplexicaudatus was most common here with 0.517 captures per net-
night (Table 16.3). The endemic Eonycteris robusta was observed in homegardens
and shrub-land. One individual of the threatened endemic Haplonycteris fischeri
was mist-netted in Gmelina forest. The endemic Ptenochirus jagori was common
in all three habitat types. Several endemic Rhinolophidae species were only caught
once in shrub-land. The little known endemic Myotis rufopictus (Heaney et al.
1998) was caught five times in total in all three habitat types (Table 16.3).

16.3.1 Species Accumulation Curves

The resident bird species accumulation curve nearly reached saturation for Gmelina
forest and homegardens but did still rise for shrub-land (Fig. 16.2A). For the subset
of forest species (Fig. 16.2B) the species accumulation curves were not completely
saturated for any of the three habitat types. Very few forest bird individuals were
observed in homegardens and shrub-land. Overall resident bird densities were
remarkable comparable between the three habitat types (Fig. 16.2C) with shrub-
land having slightly lower numbers of individual birds observed per point count.
Densities of forest birds however were much higher in Gmelina forest compared to
homegardens and shrub-land (Fig. 16.2D).
The bat species accumulation curves (Fig. 16.3A) did not reach complete satura-
tion for all three habitat types. For the subset of fruit bats, the species accumulation
curve reached saturation for homegardens and shrub-land but was still slightly rising
for Gmelina forest (Fig. 16.3B). Bat densities were highest in homegardens, fol-