Kelum Manamendra-Arachchi

Endangered anurans in a novel forest in the highlands of Sri Lanka

Abstract Context. Lands without agricultural or urban use embedded within agricultural and urban regions now account for ∼35% of Earth’s terrestrial extent. Although created by human disturbances, these ‘novel ecosystems’, usually poor in native flora and often dominated by alien species, do not require human intervention for their maintenance. Given their large and increasing area, however, their ability to support native – and especially threatened – faunas warrants investigation. With 20 species already extinct and 47 of its 91 extant species assessed as Endangered or Critically Endangered, Sri Lanka’s amphibian fauna is in trouble. The 18 anurans (12 of these Endangered) occurring above 1500 m in the island’s central mountains are at particular risk from drastic declines in the extent and quality of habitat. Habitat restoration, however, is retarded by successional vegetation being arrested at least in the decadal time-frame by alien invasive species, creating a ‘novel ecosystem’. Aim. To investigate whether such an ecosystem is able to support native anurans with a species richness and abundance comparable to that of neighbouring tropical montane cloud forest. Methods. We surveyed 110 transects (each 20 m × 2 m) across three neighbouring locations covering three microhabitat-types, and recorded 552 specimens. One-way analyses of variance and post hoc, pair-wise Tukey’s tests were performed to test for differences in species richness and abundance among the three microhabitat types. Key result. Of the 15 anuran species occurring in the neighbouring primary forest, 12 (eight of them Endangered) had established populations in the novel ecosystem (a former tea plantation), with abundances comparable to (or in some cases exceeding) those in primary forest. Conclusion. Even young secondary forest dominated by alien plant species, in which native vegetation is almost wholly absent, can provide adequate habitat for most threatened highland anurans in Sri Lanka. Implications. (1) Even if florally poor and dominated by alien species, novel ecosystems may present potential conservation opportunities for previously threatened faunas. (2) Threatened anurans exclusively dependent on primary forest and unable to utilise secondary-growth forest should receive greater conservation attention and be prioritised for in situ conservation measures. (3) Given their large and increasing extent globally, novel ecosystems should be considered as part of the area of occupancy of species able to complete their life cycles in them when assessed for conservation purposes, rather than being arbitrarily discarded as ‘degraded’.

A new frog species from rapidly dwindling cloud forest streams of Sri Lanka— Lankanectes pera (Anura, Nyctibatrachidae)

The monotypic genus Lankanectes, considered an evolutionary long branch with Indias Nyctibatrachus as its sister lineage, is represented by L. corrugatus, a species widely distributed within the wet zone of Sri Lanka up to 1500 m asl, where it inhabits a variety of lotic and lentic habitats. Here, following an integrative taxonomic approach using DNA-based phylogenies, morphology, morphometry, and ecological niche models, we describe a new species-Lankanectes pera sp. nov. The new species is distinguished from its sister species mainly by its tuberculated throat and absence of dark patches on venter, throat, manus and pes. The uncorrected genetic distances between the two Lankanectes species for a fragment of the non-coding mitochondrial 16S rRNA gene is 3.5-3.7%. The new species has a very restricted climatic distribution with a total predicted area of only 360 km2 (vs. 14,120 km2 for L. corrugatus). Unlike L. corrugatus, which prefers muddy substrates and marshy areas, the new species is observed inhabiting only pristine streams flowing through canopy covered montane forests in the highest reaches of the Knuckles Mountain range. The specialized new species will need immediate conservation attention due to its restricted distribution (montane isolate), specialized habit of inhabiting clear mountain streams, and small population size.

An integrative taxonomic review of the South Asian microhylid genus Uperodon

Based on a recent molecular phylogenetic study, the South Asian microhylid genus Uperodon (subfamily Microhylinae) currently comprises of 12 valid species that are largely restricted to India and Sri Lanka. Considering the revised generic-level status of its various members, here we review the taxonomy of all known species in this genus and clarify their nomenclatural status and geographical distribution, by integrating evidence from genetics, adult and tadpole morphology, breeding ecology, and bioacoustics. Our molecular analyses of a mitochondrial 16S rRNA gene fragment combined with external and internal morphological studies also revealed a distinct new species in the genus. This species, formally described as Uperodon rohani sp. nov., is endemic to Sri Lanka and widely distributed at lower elevations in the island. For nomenclatural stability of various previously known members, the following actions are also undertaken: (1) redescription of the poorly-defined species Ramanella anamalaiensis Rao (= Uperodon anamalaiensis) and Hylaedactylus montanus Jerdon (= Uperodon montanus); (2) neotype designation for Ramanella anamalaiensis Rao (= Uperodon anamalaiensis), Ramanella minor Rao, Ramanella mormorata Rao (= Uperodon mormorata), and Ramanella triangularis rufeventris Rao; (3) lectotype designation for Callula variegata Stoliczka (= Uperodon variegatus); and (4) synonymization of Ramanella minor Rao with Uperodon anamalaiensis.