Microtopography-induced ecohydrological effects alter plant community structure

Abstract

Microtopography affects radiation, reflection, and hydrological processes, thereby forming different microhabitats. This study aimed to determine how these processes influence the plot-scale ecosystem (similar to 0.1-1000 m(2)). Soil was sampled at 0-10 cm and 10-25 cm on depressions, gentle and steep slopes, and gullies on an artificial hillslope. Moisture, temperature, ammonium, nitrate, and plant-available phosphorus (P) were measured. Plant species distributions were evaluated using quadrats and plant nitrogen (N) and P were quantified. Resource richness, evenness, and diversity were compared for all microtopographies. Seasonal dynamics of moisture, nitrate, and available phosphorus indicate that leaching processes shape resource heterogeneity at the plot-scale. Soil nutrient levels widely differed among microtopographies during the non-growing season, but these differences decreased during the growing season. Elevated soil nitrate (but not available P) increased plant nitrate and N:P ratios on steep slopes. Higher soil available P on steep slopes was associated with an increase in the relative abundance of legumes, and subsequently stimulated the accumulation of soil N. The hydrological pathway contributed towards shaping plant community structure by regulating soil resource distribution across micro topographies. In conclusion, this study demonstrated that slight differences in microtopography (e.g., gentle versus steep slopes) alter the soil environment and plant community; therefore, sampling and treatments should be implemented under similar microtopographic conditions to avoid heterogeneity, even at such small scales.

Keywords

Microtopography; Resource heterogeneity; Resource diversity; Ecohydrology; Plant community

Published in

Geoderma
2020, Volume: 362, article number: 114119Publisher: ELSEVIER

SLU Authors

• Kardol, Paul

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Soil Science


Publication identifier

DOI: https://doi.org/10.1016/j.geoderma.2019.114119

Permanent link to this page (URI)

https://res.slu.se/id/publ/104659