Abstract
The mid-domain effect (MDE) explains altitudinal patterns of species diversity of mountainous plants at different elevations. However, its application is limited by the species life form and family flora in different layers of plant communities. To verify the MDE hypothesis at the plant community level, we chose a mountain with representative characteristics of the study area in the east of the Loess Plateau, China, such as obvious elevation (from 1324 to 2745 m) and latitude (from 36° 23′ to 39° 03′) gradients and considerable vegetation types (mainly coniferous and broad-leaved forests). We measured the life forms, families, and species diversity indices of tree, shrub, and herb communities along different elevations. We determined that the family numbers of the herb and shrub communities presented unimodal patterns across an altitudinal gradient, and the highest values occurred at intermediate elevations. The importance values of dominant families in the shrub and tree communities presented unimodal patterns, but the lowest values occurred at intermediate elevations. The species diversity indices of the herb, shrub, and tree communities conformed to unimodal change patterns following an altitudinal gradient, but the greatest diversity occurred at high, low, and intermediate elevations, respectively. At higher elevations, forbs and grasses grew well, whereas sedges grew well at lower elevations. Responses of different tree life forms to the altitudinal gradient were greater for evergreen coniferous tree species than for deciduous coniferous and deciduous broad-leaved tree species. We concluded that the MDE hypothesis of species diversity for mountainous plants is influenced greatly by the community life form and family at the plant community level in a temperate semi-arid region of the Loess Plateau, China. This conclusion tested and modified the MDE hypothesis and may be valuable for fueling prediction of biodiversity models and for the comparison with similar studies in arid and semi-arid mountainous regions.
Highlights
On the gradient patterns of species diversity due to their strong relationships with temperature, humidity, and radiation
The mid-domain effect (MDE) hypothesis of mountainous plant community needs to be further tested along altitudinal gradients and the influential factors of the hypothesis should be explored at the plant community level related to different layers of communities, those factors on life form and family flora of plant species
We made a core hypothesis that the MDE hypothesis of species diversity for mountainous plants is influenced greatly by the community life form and family flora at the plant community level and that the hydrothermal distribution status affected by latitude determined the altitudinal distribution patterns of plant community diversity on the Loess Plateau of China
Summary
On the gradient patterns of species diversity due to their strong relationships with temperature, humidity, and radiation. A warm-temperate and mid-temperate zone occur from south to north across the plateau, and a semi-arid and arid region occur from east to west; it is low in vegetation coverage, there are abundant types of vegetation on the plateau that exhibit typically community structure characteristics along diverse elevations, including grassland, bush, broad-leaved forest, mixed coniferous broad-leaved forest, coniferous forest, and subalpine meadow[38,39] These types of vegetation have distinct layers and can be divided into various communities with species possessing different life forms and belonging to different families.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
