DOI: 10.5061/dryad.k6djh9w8t
title: Constructing a database of alien plants in the Himalayas to test patterns structuring diversity

description: Differences in the number of alien plant species in different locations
 may reflect climatic and other controls that similarly affect native
 species and/or propagule pressure accompanied by delayed spread from the
 point of introduction. We set out to examine these alternatives for
 Himalayan plants, in a phylogenetic framework. We build a database of
 alien plant distributions for the Himalayas. Focusing on the
 well-documented regions of Jammu & Kashmir (west) and Bhutan
 (east) we compare alien and native species for (1) richness patterns, (2)
 the degree of phylogenetic clustering, (3) the extent to which
 species-poor regions are subsets of species-rich regions and (4)
 continental and climatic affinities/source. We document 1470 alien species
 (at least 600 naturalised), which comprise ~14% of the vascular plants
 known from the Himalayas. Alien plant species with tropical affinities
 decline in richness with elevation and species at high elevations form a
 subset of those at lower elevations, supporting location of introduction
 as an important driver of alien plant richness patterns. Separately,
 elevations that are especially rich in native plant species are also rich
 in alien plant species, suggesting an important role for climate (high
 productivity) in determining both native and alien richness. We find no
 support for the proposition that variance in human disturbance or numbers
 of native species correlate with alien distributions. Results imply an
 ongoing expansion of alien species from low-elevation sources, some of
 which are highly invasive.
description: # Constructing a database of alien plants in the Himalayas to test
 patterns structuring diversity ## Description of the dataset The dataset
 contains two files. File-1 (word file) contains a list of 31 regional
 floras and 93 research articles which were reviewed comprehensively for
 information on the distribution and elevational ranges of all alien plant
 species reported from the Himalayas. File-2 (Excel file) contains details
 of all the alien species. To harmonise taxonomy across sources, we
 assessed all species names against the updated list of botanical names
 available from www.worldfloraonline.org (World Flora Online) and resolved
 every taxon to species level. Any species whose native distribution
 extends into the Himalayan region is considered as a native, whereas a
 species whose native range is elsewhere is considered as alien. Native and
 alien distributional ranges of all species were validated from various
 online sources including the Invasive Species Compendium
 (www.cabi.org/isc), the Global Invasive Species Database
 (http://www.iucngisd.org/gisd/), and the USDA-GRIN
 (https://npgsweb.ars-grin.gov/). A complete dataset of alien species along
 with the hyperlinks to the sources are provided for each species in the
 file. Species were classified as cultivated (species that are cultivated
 by humans for food or ornaments) or naturalised (a species that does not
 require human assistance to reproduce and maintain itself in its natural
 environment). Note that many cultivated species may also be naturalised,
 but we prioritise cultivated over naturalised in this compilation. We also
 listed each species as invasive (species considered to have harmful
 impacts) as classified by the Global Invasive Species databases (hence not
 necessarily invasive in the Himalayas). To assess source regions we
 recorded the native range of alien species to the continents (Africa,
 Australia, Europe, North America, and South America). Tropical Asia and
 Temperate Asia were not separated because the Himalayas act as a boundary
 between these two regions and species distributions have been assigned too
 crudely to classify them unambiguously. Plant species were also classified
 into three biogeographic categories, i.e., tropical, temperate, and
 cosmopolitan, based on the centre of species diversity within each genus.
 These data are unavailable for 525 species (&lt;5%, 378 native species,
 147 alien species) which we excluded from relevant analyses. ##
 Description of the variables in the data 1. Synonyms: The columns contain
 names of species which are currently treated as synonyms of botanical
 names reported in the column Species. All species names reported in the
 published literature were checked for their latest taxonomic status at
 www.worldfloraonline.org (World Flora Online) and all synonyms were placed
 in a separate cell against the currently accepted names of the species. 2.
 Species: The column contains all currently accepted names of alien plant
 species reported in the published literature from the Himalayas. Blank
 cells mean no synonyms reported for the species in the Himalayas. 3.
 Authority: The column contains the author's name of the currently
 accepted botanical name of alien plant species in the Himalayas. 4.
 Family: Family of the species. 5. Genus: Genus of the species. 6. Life
 form: Life forms of the species include Trees, Shrubs, Herbs, Woody and
 herbaceous Climbers, Palms, and Bamboo. 7. Habit: This column includes the
 nature of the alien species including Naturalised, Invasive, Cultivated,
 and Unknown. 8. Affinity: This column includes the climatic affinity of
 the species such as Tropical, Temperate, Cosmopolitan, and Unknown. 9.
 Names of the continents: These columns show the native range of the alien
 species in the Himalayas. The 1 represents that the species is native to
 the continent and the black cell shows either the absence or non-native
 presence of the species in the continent. 10. Names of geographic regions
 in the Himalayas: These columns represent the presence of species within
 the sic geographic regions of the Himalayas, i.e., Arunachal Pradesh,
 Bhutan, Nepal, Uttarakhand, Himachal Pradesh, and Jammu and Kashmir. The 1
 represents the presence of species in the geographic region whereas blank
 means the absence of species in the respective geographic region. 11.
 Lower Limit: Lowest elevation of the species in the Himalayas. Blank cell
 means elevational range not reported for the species in the Himalayas. 12.
 Upper Limit: Highest elevation of the species in the Himalayas. Blank cell
 means elevational range not reported for the species in the Himalayas. 13.
 Range: Range of elevational range of the species in the Himalayas in
 meters. Blank cell means elevational range not reported for the species in
 the Himalayas. 14. URL: The column contains hyperlinks to the original
 sources showing the distribution status of the species. 15. Common name:
 The column shows common names of the species in the Himalayas or
 elsewhere. Blanck cells mean common names are not available for the
 species.