Does Regular Harvesting Increase Plant Diversity in Buffer Strips Separating Agricultural Land and Surface Waters?

Abstract

Vegetated buffer strips are often established in agricultural landscapes as an "edge of the field" mitigation measure against diffuse nutrient pollution of the aquatic environment. Harvesting of the vegetation has been suggested as a possible management strategy to prevent build-up of excessive amounts of nutrients in buffer soils and, at the same time, harvesting can have a positive effect on the diversity of the vegetation. However, the response of the vegetation to harvesting likely depends on taxonomic and functional characteristics. In the present study, we explored effects of harvesting frequency (by comparing harvesting once, twice, and four times per year to an unharvested control) on the taxonomic and functional trait composition of four different types of plant communities in buffer strips in Denmark. We found that one to two harvests per year mediated an increase in the diversity of the vegetation in low diversity buffer strips dominated by tall and productive herbs (tall herb fringe), whereas the diversity remained unchanged in buffer strips dominated by grasses as well as in more diverse buffer strips with rich fen and wet meadow species. We also found that harvesting changed the compositional patterns in the tall herb fringe community, with an increasing abundance of grasses and a declining abundance of tall herb species, in particular at a high harvesting frequency. Concomitant with these taxonomic changes, we observed changes in the trait composition of the community. The abundance of tall species declined in the tall herb fringe and in the tall grass community. Similarly, the abundance of productive species (as indicated by high Ellenberg N and Ellenberg R values) declined in the tall herb fringe (in areas harvested four times per year). We conclude that low frequency harvesting is a promising management strategy to increase plant diversity in buffer strips with an initially low diversity and high productivity and that harvesting over time can mediate a shift in compositional patterns toward less productive species.

Researcher effects on the biological structure and edaphic conditions of field sites and implications for management

“…For instance, reduced human activity during the COVID‐19 lockdowns led to increased abundance of important fish species (e.g., Siganus argenteus , Scolopsis ghanam ) on shallow coral reefs along the northern Gulf of Aqaba (China et al, 2021). Additionally, harvesting plants can defoliate habitat, alter plant community composition, and impact nutrient processing rates (Hille et al, 2018; Jabłońska et al, 2021). Soil coring and soil pits may also adversely affect environmental processes.…”

Researcher effects on the biological structure and edaphic conditions of field sites and implications for management

“…For instance, collecting and interacting with wild animals can have adverse effects on their populations and behaviors (Ikin 2011;China et al 2021;Lewis et al 2022). Additionally, harvesting plants can defoliate habitat, alter plant community composition, and impact nutrient processing rates (Hille et al 2018;Jabłońska et al 2021). Soil coring and soil pits may also adversely affect environmental processes.…”

Riparian Land Use and Hydrological Connectivity Influence Nutrient Retention in Tropical Rivers Receiving Wastewater Treatment Plant Discharge

“…Several retention mechanisms described in the literature are coupled with the presence of riparian areas. For instance, riparian plant communities can strongly affect retention performance by influencing runoff hydrology, evapotranspiration, nutrient uptake, aquatic metabolism, and soil nutrient recycling (Lupon et al, 2015;Dodds et al, 2017;Hille et al, 2018). The riparian corridor structure, in turn, shapes overall stream morphology and nutrient attenuation by controlling the distribution of sediments, habitat patches, water flow, transient storage, and redox conditions (Pinay et al, 2018).…”