Table 20. Continued. Artiodactyla Cervus mariannus Sus barbatus Native species Non-volant species Large fruit bats Small fruit bats Microchiroptera All natives Introduced species All species Distributions (after Heaney et al. 1987): LEYTE restricted to Leyte; MIND restricted to Mindanao faunal region; PHIL widespread in oceanic Philippines; WIDE occurring outside of oceanic Philippines, t Introduced commensal species. typically have low population densities and thus require larger areas to sustain viable populations. We believe it likely that the absence of pigs and deer on Maripipi stems from natural extinction. However, it is certainly possible that both species may have become extinct through relatively recent hunting pressures. Small mammals with restricted elevational ranges also appear to be susceptible to extinction on small islands, presumably because of narrower ecological tolerances. On Leyte, Batomys salomonseni was restricted to high-elevation forest, where it was the most frequently trapped species (table 1). However, it was rare in similar habitat on Biliran and was absent from Maripipi. The distribution of Apomys littoralis is suggestive of similar limitations. The situation for the widespread Philippine native rat, Rattus everetti, provides an interesting contrast. In surveys on Leyte (this study, table 1 ) and Luzon (Rickart et al, 1 99 1 , this species was common in habitats ranging from lowland dipterocarp forest to high-elevation mossy forest. Perhaps because of this broad ecological tolerance, it has survived on Maripipi, where more specialized species have not. Ecological factors may also explain the distributional limitations of small fruit bats among these islands. Of the species that were common on Leyte and Biliran, Haplonycterisfischeri and Ptenochirus minor were conspicuous in that they were almost never encountered outside of forested habitats. This inability to tolerate disturbance may be associated with their apparent absence from Maripipi. Netting and Trapping Success Our field work on Leyte served as a basis for formulating several general predictions concerning patterns of variation in species richness and abundance of small mammals in Southeast Asia (Heaney et al, 1 989). Subsequent studies generally have supported these predictions (Heaney & Rickart, 1 990; Heaney et al, 1 99 1 ; Rickart et al, 1 99 1 , and we believe that data from Biliran and Maripipi can be used to further test their generality. The relevant predictions from Heaney et al. (1989) derived from our studies on Leyte and Negros are (1) in forested habitats, species richness and relative abundance of fruit bats should be highest in the lowlands and decline with increasing elevation, (2) species richness of fruit bats should be lower in agricultural areas, where geographically widespread species should predominate, (3) non-volant mammals should not exhibit highest species richness in lowland forest, (4) abundance of non-volant mammals should increase with elevation, and (5) endemic species of fruit bats and non-volant mammals should occur in primary forest, whereas non-endemics should predominate in disturbed habitats. Data on species richness of small fruit bats on Biliran and Maripipi (table 5) generally support predictions 1 and 2. Species richness was highest at the lowest elevation forested sites (sites B2 and Ml) and declined with elevation to reach lowest values in mossy forest. On both islands there was also an indication of a decline in relative abunrickart ET AL: MAMMALS OF LEYTE, BILIRAN, AND MARIPIPI ISLANDS 57