The mid-domain effect of mountainous plants is determined by community life form and family flora on the Loess Plateau of China

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.

Plant Allometric Growth Enhanced by the Change in Soil Stoichiometric Characteristics With Depth in an Alpine Meadow Under Climate Warming

“…First, for the plant growth indices, regression analysis software in the SPSS 23.0 software was used to explore the relationship between plant biomass indices (aboveground biomass, belowground biomass, and total biomass) and other plant growth indices (density, height, frequency, and coverage) in CK and W treatments, and the optimal equation was selected from the following conventional functions: exponential, linear, logarithmic, quadratic polynomial, and power functions ( Xu et al, 2021a , b ). The selection criteria had two conditions: (1) the determination coefficient of R 2 value was the largest and (2) the significance test of the p- value was the smallest and less than 0.05 ( Xu et al, 2021a , b ). The optimal fitting plots were drawn with Origin 9.1 software (OriginLab Corp., Hampton, MA, United States).…”

Precipitation and potential evapotranspiration determine the distribution patterns of threatened plant species in Sichuan Province, China

“…The MDE was introduced to address the complexity of climatic and non-climatic factors on richness patterns 21 , 22 , 42 . Some studies supported the MDE in other regions of China 23 , 25 . However, the MDE was found to be the least expressed variable in the richness pattern of threatened species (Fig.…”

“…Further, the MDE states that the diversity in species richness in mountain domains is independent of any environmental gradients and that it represents a "null model" for diversity patterns 21,22 . Some studies have validated the effect of the MDE in the mountains of China [23][24][25] . In the present paper, the effects of temperature, precipitation, PET, DIST, and the MDE responsible for the richness pattern of threatened plants in Sichuan Province were examined.…”

From vegetation ecology to vegetation science: current trends and perspectives

“…The study of vegetation and its changes along elevational gradients remains not only a popular but also a challenging research topic in vegetation ecology (Willig et al 2003, Sundqvist et al 2013) since these gradients can be used as research systems to understand vegetation responses to environmental changes. Vegetation compositional and structural heterogeneity related to elevational gradients has been repeatedly analyzed for tree species, usually on a single gradient (e.g., Vázquez G & Givnish 1998, Kappelle & van Xu et al 2021, Zhao et al 2022.…”