Plant community data from a statewide survey of paired serpentine and non-serpentine soils in California, USA

Soils derived from ultramafic parent materials (hereafter serpentine) provide habitat for unique plant communities containing species with adaptations to the low nutrient levels, high magnesium: calcium ratios, and high metal content (Ni, Zn) that characterize serpentine. Plants on serpentine have long been studied in evolution and ecology, and plants adapted to serpentine contribute disproportionately to plant diversity in many parts of the world. In 2000-2003, serpentine plant communities were sampled at 107 locations representing the full range of occurrence of serpentine in California, USA, spanning large gradients in climate. In 2009-2010, plant communities were similarly sampled at 97 locations on nonserpentine soil, near to and paired with 97 of the serpentine sampling locations. (Some serpentine locations were revisited in 2009-2010 to assess the degree of change since 2000-2003, which was minimal.) At each serpentine or nonserpentine location, a north- and a south-facing 50 m x10 m plot were sampled. This design produced 97 “sites” each consisting of four “plots” (north-south exposure, serpentine-nonserpentine soil). All plots were initially visited >3 times over 2 years to record plant diversity and cover, and a subset were revisited in 2014 to examine community change after a drought. The original question guiding the study was how plant diversity is shaped by the spatially patchy nature of the serpentine habitat. Subsequently, we investigated how climate drives plant diversity at multiple scales (within locations, between locations on the same and different soil types, and across entire regions) and at different levels of organization (taxonomic, functional, and phylogenetic).

Relationship between Diversity and Stability of a Karst Plant Community

The relationships among species diversity, functional diversity, functional redundancy, and community stability are central to community and ecosystem ecology. This paper examines plant communities at different stages of vegetation restoration in the Guizhou karst plateau to study the relationship among functional diversity, functional redundancy, and stability of plant communities. The most important results include the following. (1) Species diversity (SD), functional redundancy (FR), and stability (STB) gradually increased with restoration, and there were significant differences among the different stages; functional diversity (FD) increased at first and then decreased, and reached the highest level at the tree irrigation stage. (2) Plant height (PLH) and specific leaf area (SLA) were functional traits that affected the diversity and stability of the plant community, and PLH was positively correlated with plant community diversity and stability, while SLA was negatively correlated with plant community diversity and stability. (3) During the community recovery, FD and FR interacted to maintain stability. In the early and late stages of recovery, the effect of functional redundancy on stability was greater than that of functional diversity, but it was the opposite in the middle stages. (4) The tree irrigation stage is the likely point at which the species diversity of plant communities in karst areas reached saturation, and the growth rate of functional redundancy after species diversity saturation was greater than that before saturation.

Rotational grazing increases purple prairie clover frequency in the rangeland plant communities under semi-arid environment

Purple prairie clover (PPC, Dalea purpurea Vent.) is a grazing tolerant perennial legume with good nutritional quality and is widely distributed across North America. Deferred rotational grazing (DR) and continuous grazing (CG) are the most widespread grazing systems on North American grasslands. We conducted a 10-year grazing study to assess the effects of environmental factors and grazing on the frequency of PPC in plant communities. The results showed that the frequency of PPC decreased and then increased with increasing precipitation under CG (P<0.05), while there was no significant change under DR (P>0.05). Meanwhile, PPC frequency increased with temperature under DR (P<0.05), but did not change under CG (P>0.05). Both grazing systems and the number of grazing years had a significant effect on PPC frequency (P<0.05), and there is no interaction between those two factors (P>0.05). We found that from 2011 to 2020, the growth rate of PPC population is 18.24% and 11.69% per year under DR and CG grazing, respectively. Moreover, after 10 years of grazing, the PPC increase in DR was 22.86% higher than that of CG. Thus, selecting the DR grazing system can increase PPC and is an effective practice for coping with environmental changes.

Effects of Plant Communities on Human Physiological Recovery and Emotional Reactions: A Comparative Onsite Survey and Photo Elicitation Study

We investigated the effects on humans, in terms of skin conductance levels (SCLs) and positive and negative affect schedule (PANAS) scores, of plant communities that differed in their vegetation structure (single-layer woodland, tree-shrub-grass composite woodland, tree-grass composite woodland, and single-layer grassland) through two perceptual methods: onsite surveying and photo elicitation. The results showed that (1) the choice of perception method significantly impacted the PANAS scores of the participants but had no influence on the SCL and (2) viewing a single-layer grassland reduced the SCL (representing the physiological stress level) and improved the positive affect score. The recovery effects for the four vegetation communities were ranked in the order of single-layer grassland > tree-shrub-grass composite woodland > single-layer woodland > tree-grass composite woodland. (3) Gender and professional background significantly impacted the plant community perception methods and landscape experience, and negative affect scores were lower for male participants than for female participants. Participants without backgrounds in landscape design exhibited higher positive affect scores under photo elicitation. Based on the conclusions drawn above, the onsite survey is preferable between the two perception methods. It is recommended that in future landscape designs, combinations of plant community types should be reasonably matched through onsite perception. These research results can provide a scientific basis for the future design of landscapes based on perception experience.