Impact of habitat alteration on amphibian diversity and species composition in a lowland tropical rainforest in Northeastern Leyte, Philippines

Abstract

Syrus cesar pacle Decena * , carlo Aguirre Avorque, ian christopher pacle Decena, pol Delbert Asis & Bryan pacle the impact of anthropogenic habitat alteration on amphibians was investigated, employing an investigative focus on leaf-litter and semi-aquatic species across different habitat alteration types. The habitat alteration types which include primary forest, selectively logged primary forest, secondary forest, abandoned farm areas and pasture (this represents a gradient of habitat alteration ranging from least altered to most altered, respectively) also encompass two habitat types: stream and terrestrial. Species assemblage was compared between habitat alteration types and habitat types, where a total 360 leaf-litter and semi-aquatic amphibians were observed (15 species, 6 families). It was found that amphibian abundance was significantly higher in both forest and stream habitat, and species richness did not differ with respect to habitat alteration type. It was determined, however, that species richness was highly dependent on habitat type (significantly higher in stream habitat). Meanwhile, diversity (Shannon-Wiener) was significantly higher in both forest and stream habitat, and species composition differed markedly between habitat alteration types for stream strip plots. forest habitat exhibited domination by forest specialist species, while altered habitat (abandoned farm areas and pasture) exhibited domination by open-habitat specialist species. Additionally, strong relationships were found between species composition and abundance, as well as richness and diversity (within the measured habitat structures and observed microclimatic conditions). Analyses determined that the higher abundance of leaf-litter and semi-aquatic amphibians was best explained by higher DBH (1.3 m from the ground) and lower temperature and the higher species richness was best explained by higher understorey density. Additionally, higher diversity was associated with increasing understorey density, tree density and temperature. In general, the assemblage of leaf-litter and semi-aquatic amphibians in the lowland tropical rainforest in northeastern Leyte was affected by habitat alteration, highlighting the ongoing importance of conservation efforts. Though the Philippines is commonly known as one of the most important biodiversity hotspots on Earth 1 , there is undoubtedly cause for concern, since southeast Asia has the highest relative rate of deforestation of any major tropical region 2. In the Philippines, an average of 162,000 ha of forests are cleared per year 3 and consequently, the remaining primary forest of the country represents approximately only 3% 1 of land area. This decline of the country's forest is commonly attributed to logging, urbanization and agricultural expansion, as well as other peripheral factors such as shifting cultivation, unorganized encroachment on forest lands, squatting, migration to upland forested areas, and government-sponsored settlement schemes 3,4. Deforestation due to these humaninduced acti...

The City in the Tropics: Lizard Community Structure and Spatial Resource Use Along an Habitat Gradient of the Dahomey Gap (West Africa)

“…The species richness reduction from forest to urban areas may also be interpreted as an effect of habitat loss on forest-specialists (Turner 1996;Lea et al 2003;Edwards et al 2013;Decena et al 2020). Indeed, studies from tropical Africa have revealed that forest loss (by slash-and-burn shifting cultivations or by direct tree cutting) at the local scale produced a considerable reduction in the species richness of lizards (Akani et al 2018).…”

Impact of Land Use Conversion on Carbon Stocks and Selected Peat Physico-chemical Properties in the Leyte Sab-a Basin Peatland, Philippines

“…All the standing live trees with a DBH of ≥ 5 cm inside the plot were counted and measured in terms of DBH and height. The height of the tree was visually determined through the use of a 2-m long calibrated pole (Madeira et al, 2009, Decena et al, 2020. In addition, each of the tree individuals sampled were identi ed up to species level whenever possible using the pictorial Handbook on Peat Swamp Flora of Agusan Marsh, Mindanao of The same procedures in the identi cation were also applied to understorey/grasses.…”

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“…Changes in habitat characteristics are also linked to habitat alteration, and these changes are expected to have an impact on amphibian diversity (Vallan 2002). A number of habitat components and characteristics have been shown to affect amphibian diversity and distribution, such as canopy cover, leaf litter cover, understory density, temperature and rainfall, elevational gradient, and forest patch (Urbina-Cardona et al 2006; Laurencio and Fitzgerald 2010; Russildi et al 2016; Decena et al 2020). The loss or reduction in canopy cover can substantially result in the decline in species, especially those rainforest specialist amphibians, since canopy cover provides necessary habitat conditions (Cortés-Gómez et al 2013).…”