Spatial heterogeneity of plant community composition and diversity on phytogenic mounds caused by water erosion

ABSTRACT

Background

A phytogenic mound is a special microtopography that forms under a perennial plant canopy in erosion-affected areas. These mounds result in spatial microenvironmental heterogeneity and thus are important factors in determining plant community composition.

Aims

We assessed whether and how plant composition and diversity differed on different parts of mounds in water erosion-affected areas and evaluated which environmental variables were related to the compositional difference.

Methods

We compared plant community composition and diversity on the upslope (UP) and downslope (DN) parts of mounds and inter-canopy surfaces (IS) along four slope gradients.

Results

On slopes < 46.6%, vegetation cover, biomass, density and diversity of plant communities did not significantly differ between UP and DN. However, these plant community attributes were higher UP than in IS and DN on steeper slopes (> 46.6%). On such slopes phanerophytes and chamaephytes occurred only UP. Sediment accumulation, light intensity, soil moisture, and surface hardness were significantly correlated with the community composition on mounds, while soil N, P and K showed a weak relationship.

Conclusion

Only the UP of mounds on steep slopes maintained high plant diversity in water erosion-affected areas, which is especially important for shaping plant community patterns on seriously eroded slopes where plant colonisation is limited.

KEYWORDS:

• Phytogenic mound
• plant community
• sediment accumulation
• soil erosion
• vegetation patches

Acknowledgements

Acknowledge the assistance of the Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation and Ansai Ecological Experimental Station for Soil and Water Conservation, CAS.

Disclosure statement

The data and findings presented in this manuscript have not been published nor are under consideration for publication anywhere else. All persons entitled to authorship have been so named and all authors have seen and agreed to the submitted version of the manuscript.

Supplemental material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the China Postdoctoral Science Foundation [2018M643689]; Shaanxi Natural Science Foundation Program [2019JM-460]; and National Natural Science Foundation of China [41401306].

Notes on contributors

Huadong Du

Huadong Du is interested in plant adaptations to soil erosion disturbance.

Benyan Ning

Benyan Ning studies plant-environment interactions and the evaluation of vegetation restoration benefits.

Juying Jiao

Juying Jiao focuses on slope erosion and sediment production processes, and the vegetation restoration on the Loess Plateau.

Yichen Cao

Yichen Cao studies plant-environment interactions and the effects of soil erosion on native plant population dynamics.