Impacts of road on plant invasions in the Middle Mountain region of central Nepal

Biological invasion is triggered by human development activities such as the construction and expansion of road networks.Road verges serve as important habitats and corridors for the distribution of invasive alien plant species(IAPS)between geographically distant habitats.However,the trajectory of plant invasion and the data regarding the impact of roads on IAPS distribution are relatively poor in Nepal.Here,we surveyed two road types(main roads and feeder road)in the Middle Mountain region of central Nepal in order to investigate how different road types are driving the dispersal of IAPS along road verges and the adjacent natural habitats.Systematic sampling was conducted at ca 2.5 km intervals along the roads.At each sampling site,paired plots(25 m×4 m)were sampled:one adjacent to and along the road,and another 20 m away and parallel to it in the interior habitat.Our results revealed that the main road verges had a higher cover(33%)and a larger number of IAPS(14 species)than the feeder road(25%;10 species).The IAPS cover and richness were significantly higher along verges than in the adjacent interior habitats for both road types,indicating that roads are contributing as corridors for the dispersal of IAPS in the Middle Mountain areas of central Nepal.Further,elevation,tree canopy,and disturbances(grazing/mowing/trampling)were found to be the key factors that determine spatial distribution of IAPS along road verges.We emphasize that regular monitoring of vegetation along the road verges can help with the early detection and control of potential IAPS in the region before they become problematic.

The potential drivers in forming avian biodiversity hotspots in the East Himalaya Mountains of Southwest China

Little has been published to describe or interpret Asian biodiversity hotspots,including those in the East Himalayan Mountains of Southwest China(HMSC),thus making necessary a review of the current knowledge.The Pliocene and Pleistocene geological and glacial histories of the Asian continent differ from those of Europe and North America,suggesting different mechanisms of speciation and extinction,and,thus,different responses to climate changes during the Quaternary glaciations.This short review summarizes potential drivers in shaping and maintaining high species richness and endemism of birds in the HMSC.The geographical location at the junction of different biogeographical realms,the wide range of habitats and climates along the extensive elevational range,the complex topography and the distinct geological history of this region have probably contributed to the evolution of an exceptionally species-rich and endemic-rich,specialized montane avian fauna.The Mountain systems in the HMSC may have provided refugia where species survived during the glacial periods and barriers for preventing species dispersal after the glacial periods.More studies are required to further test this refugia hypothesis by comparing more cold-tolerent and warm-tolerent species.

Facies analysis and palaeoecology of the Jurassic Spiti Shale Formation in the Spiti area,Northern India

The Spiti Shale Formation is a widely distributed stratigraphic unit of the passive northern margin of the Indian craton,deposited between the Callovian and earliest Cretaceous.The siliciclastic strata are dominated by dark-grey to black argillaceous silt.As the formation has undergone intense tectonic stress involving folding and faulting,it is very difficult to document a complete section.In the type area,the Spiti Valley,six sections have been measured that document parts of the three informal members of the formation,the Lower,Middle,and Upper members.Despite its uniform appearance,eight facies/biofacies types could be distinguished,ranging from the anoxic shale facies,with ammonites and belemnites as the only faunal elements,to the dysoxic Malayomaorica and Bositra biofacies,and the oxic to anoxic offshore shelf facies,which are characterized by low-diversity macrobenthos associations.Other facies are the condensed glauconiticphosphoritic mudrock facies and the Fe-oolitic siltstone facies(both characterized by sediment starvation),the aerated argillaceous silt-sandstone facies,and the tide-influenced nearshore shelf facies.The benthic macrofauna represents four bivalve-dominated associations all characterized by a very low to low species diversity.They are the Bositra buchii,the Australobuchia spitiensis,the Palaeonucula cuneiformis-Pruvostiella hermanni-Indogrammatodon egertonianus,and the Malayomaorica sp.-Australobuchia spitiensis-Retroceramus haasti association.Sediments and macrobenthic associations indicate that the Spiti Shale Formation represents outer to inner shelf environments,which for much of the time were subjected to upwelling and anoxic to dysoxic conditions.Distinct shallowing at the top characterizes the transition to the overlying Lower Cretaceous Giumal Formation.