Influence of elevation on bioregionalisation: A case study of the Sino‐Himalayan flora

Abstract

Aim Elevation is an important factor that influences bioregionalisation in mountainous areas, but its effects are not well known. Taking the Sino‐Himalayan flora as a case, we aimed to test the effect of elevation on bioregionalisation and provide a regionalisation scheme of the Sino‐Himalayan flora. Location The Sino‐Himalaya (East Himalaya, the Hengduan Mountains and the Yunnan Plateau in China). Taxon Angiosperms. Methods We compiled distribution data and elevation ranges of angiosperms in the Sino‐Himalaya and adjacent areas and reconstructed a species‐level phylogenetic tree of 19,313 angiosperm species. The area was divided into 398 grid cells, each 1 × 1°. Nine datasets of different elevation ranges were then used to delineate the flora of the Sino‐Himalaya and adjacent areas using the phylogenetic dissimilarity approach. Results A comparison of nine regionalisation schemes of the Sino‐Himalayan flora based on different elevation range datasets revealed that more than half of grid cells were allocated to more than one subregion. Most of these grid cells were located in areas with a wide range of elevation and/or at the boundaries between subregions. After revising the subregion allocations of eight shifting grid cells, we generated a phylogeny‐ and elevation‐based regionalisation scheme of three regions, comprising eight subregions, for the Sino‐Himalayan flora. Main conclusions By integrating phylogenetic and elevational information, the Sino‐Himalaya can be divided into three floristic regions: the Yunnan Plateau region, the Hengduan Mountains region and the East Himalaya region. Our study provides novel insights into the regionalisation of the flora and highlights the importance of incorporating elevation data in the bioregionalisation of areas with a broad elevational range.

Cryptic Species Diversification of the Pedicularis siphonantha Complex (Orobanchaceae) in the Mountains of Southwest China Since the Pliocene

“… Bayesian phylogeographical reconstruction of ancestral area of the Pedicularis siphonantha complex in the Sino-Himalayan region using the modified nrITS + ptDNA dataset (see above). Pie charts and thickness of branch represent the marginal probabilities for potential ancestral areas with each subregion ( Liu et al, 2021 ), represented by a different color. BI PPs are above branches (* = 1.00).…”

“…The concatenated nrITS and ptDNA dataset, including all samples of the P. siphonantha complex and two outgroups Pedicularis amplituba H. L. Li and Pedicularis tachanensis Bonati, was imported into BEAUti with “beast-classic package” ( Lemey et al, 2009 ). Samples were assigned to one of four subregions of the Sino-Himalayan flora following Liu et al (2021) . Taking into account the center of endemism identified by Zhang et al (2016) , two samples of Pedicularis siphonantha (D1, D2) collected from Yadong country in the middle Himalaya were assigned to subregion IIIa.…”

Biogeographic Patterns and Richness of the Meconopsis Species and Their Influence Factors across the Pan-Himalaya and Adjacent Regions

“…Most studies have shown that the Qinghai-Tibet Plateau sensu lato (QTPsl) is not a natural tectonic association, but rather comprises a "plateau platform" (i.e., Qinghai-Tibet Plateau sensu stricto; QTPss) [7,8], the Himalaya, and the Hengduan Mountains [9,10]. Together these three regions are also referred to as the pan-Himalayan region [10,11] which boasts of complex topography, diverse geomorphological types, a wide altitudinal range, and different soil textures and geological conditions. This region, where one can observe diverse habitats within a short distance, supports a variety of endemic and endangered species [11,12].…”

“…Together these three regions are also referred to as the pan-Himalayan region [10,11] which boasts of complex topography, diverse geomorphological types, a wide altitudinal range, and different soil textures and geological conditions. This region, where one can observe diverse habitats within a short distance, supports a variety of endemic and endangered species [11,12]. The pan-Himalayan region is an important biodiversity hotspot with the world's highest diversity of alpine plants, attracting extensive scientific attentions [10,13,14].…”

“…Climate variables can determine the geographic distribution patterns of plant species [22] in addition to several non-climatic factors, such as topography, soil types, and land use, which equally impact species distribution [23]. The geographical distribution of alpine plants, in particular, is sensitive to the interaction between climate and topography [11,24]. Furthermore, human disturbances in mountainous landscapes not only accelerate climate change but also cause severe habitat loss and fragmentation and support the invasion of alien species, which are often directly or indirectly related to the loss of biodiversity [18,[25][26][27].…”