Road-Edge Effects on Herpetofauna in a Lowland Amazonian Rainforest

Avorque

et al. 2020

Sci Rep

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...

Section: Discussionsupporting

confidence: 89%

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

Avorque

et al. 2020

Sci Rep

“…Based on our literature review, we determined that specific taxa would be affected by road noise, light, temperature change or other effects at different widths and thus we chose 100 m (small carnivores and rodents, [39]; birds, [14], amphibians [14, 40]), 500 m (mid-sized carnivores, [41] and 1000 m (ungulates [39, 42]) from roads to account for impacts of forest loss and edge effects due to roads on various species. While we recognized that tropical ecosystems and species may vary in their response to traffic on roads, research on specific distances affecting tropical species is relatively rare.…”

Section: Methodsmentioning

confidence: 99%

The road to deforestation: Edge effects in an endemic ecosystem in Sumatra, Indonesia

et al. 2019

Worldwide, roads are a main driver of deforestation and degradation as they increase forest access along the forest edge. In many tropical areas, unofficial roads go unreported and unrecorded, resulting in inaccurate estimates of intact forested areas. This is the case in central Sumatra, which boasts populations of critically endangered Sumatran elephants ( Elephas maximus sumatrensis ), tigers ( Panthera tigris sumatrae ) and other endemic flora and fauna that make the area globally unique. However, maps do not reflect the reality of forest loss in the area. Here we present new maps from 2002 and 2016 of digitized and ground-truthed roads in one of Sumatra’s unique lowland tropical protected areas, Tesso Nilo National Park. Using our newly created roads dataset, we examine the distribution of forest with respect to distance to roads. Our data show >2,400 km of roads within the national park in 2016 –nearly a 10-fold increase from roads known in 2002. Most forest (82–99%) within Tesso Nilo falls within 100 m, 500 m, and 1000 m of road edges. Length of road increased 157% and road density increased from 1.06 km/km 2 to 2.63 km/km 2 from 2002–2016. Our results suggest that this endemic ecosystem is facing substantial threat from roads and their associated impacts. Without swift management action, such as road closures and increased enforcements by park management, this ecosystem, and its endemic wildlife, could be lost. It is imperative that protected areas worldwide more rigorously consider roads and road effects on ecosystem fragmentation in their conservation plans.

Tropical Conservation Science

“…Demand for expanding road networks has been concomitant with mass production of automobiles, and the pervasiveness of impacts of roads on biodiversity has long been recognized (Coffin, 2007;Stoner, 1925Stoner, , 1936. Roads fragment the landscape by creating edge effects and inhibiting dispersal or movement and expose animals to traffic collisions and mortality as well as alter assemblage composition (Coffin, 2007;Laurance, Goosem, & Laurance, 2009;Maynard, Aall, Saenz, Hamilton, & Kwiatkowski, 2016). This in turn can affect ecological and evolutionary dynamics by reducing effective population size, skewing sex ratios, and reducing genetic diversity (Balkenhol & Waits, 2009).…”

Section: Introductionmentioning

confidence: 99%

Seasonal Activity and Species Habitat Guilds Influence Road-Kill Patterns of Neotropical Snakes

Sosa

Schalk

2016

Animal road mortality is the product of multiple factors. We sought to examine the impact of roads on Bolivian biodiversity by quantifying road mortality in a community of tropical snakes and examine variation in road-kills in the context of extrinsic (seasonal effects) and intrinsic factors (habitat guild, sex). From 2007 to 2011, we surveyed the old Santa Cruz-Cochabamba highway and local dirt roads in Florida Province, Santa Cruz Department, Bolivia. We observed 1,444 snake road-kills comprised at least 32 species from 21 genera and 4 families. Nearly one fifth (18.4%) of road-killed species are endemic to the region. A temporal peak in road mortality was observed in February in the middle of the rainy season and was lowest in July coinciding with the dry season. Male snakes were more frequently killed than females and male mortality peaked during the mid to late rainy season. Habitat guild had a significant influence on the species occurrence during the road surveys; roadkills of terrestrial snakes were observed more frequently compared with fossorial, arboreal, semi-arboreal, and semi-aquatic species. The impact of roads on Bolivian biodiversity, including snakes, is expected to increase, as road networks in the region continue to expand. Documenting additional interspecific and intraspecific variation in vulnerabilities to road mortality is needed to better understand the long-term impacts of roads on population persistence as well as inform the design and implementation of mitigation efforts.