From dense swards to biodiverse roughs

Summary

For golf courses to support biodiversity and ecological functions such as pollination services, there is a need to convert rough areas into more diverse vegetation. In most cases, this transition is hampered by low seed input and highly competitive grass vegetation under high nutrient conditions.

Methods and strategies to overcome these limitations are needed. This project comprised field experiments at Oslo GK and in four other species-poor grasslands in Norway, plus a demo trial at Sigtuna GK, Sweden. These involved a set of treatments to reduce the competitive dominance of grasses (cutting frequency, hay removal, nitrogen immobilisation by sawdust application, seeding of the hemiparasitic species Rhinantus minor) in 2017, and addition of seeds of regional seed mixtures in 2018 to overcome seed limitation.

In 2020, some of the seeded species had established and some had started to flower, but there were large differences between locations and some differences between treatments. Apart from seeding, removal of cut hay was the single most important management measure to improve plant diversity. Whether the vegetation was cut once or twice was not as important at this stage. Addition of sawdust had no major effect on results. Establishment of Rhinanthus was not successful on most sites, but reduced rough density and improved playing quality at Oslo GK.

Seedling establishment was good in many plots, but the transition from seedling to flowering plants was difficult at four of the five locations. The most likely reason is asymmetric competition, as dense grass was negative for seedling survival. In addition to measures to reduce grass dominance such as cutting and hay removal, a good strategy for sites with dense grass cover is to interseed the more competitive species, e.g. Leuchantemum vulgare, Achillea millefolium and Lotus corniculatus, from the regional species pool.

Three years is a very short time to reduce grass dominance and obtain substantial changes in species composition. Despite that, we found preliminary effects on flower resources and pollinator abundance two years after seeding and three years after initiation of treatments. Contributions to flowering abundance came partly from seeded species, but also from the development of existing species and spontaneous establishment. Treatments to ease establishment of seeded species were also positive for development of species present before seeding.


Golfbaner kan ha en viktig rolle i å fremme biologisk mangfold og økologiske funksjoner i landskapet. Mange golfbaner har imidlertid produktiv jord. Et av de viktigste tiltakene for å etablere mangfoldig vegetasjon og skaffe ressurser for pollinatorer er å redusere produktiviteten. Målet for prosjektet er å skaffe kunnskap om hvordan slåtteregime, tilsetninger av karbon i jord, såing av blomsterengfrø, og såing av halvparasittiske planter kan brukes til å redusere konkurransen fra gress og øke det biologiske mangfoldet i rough. Forsøk vil bli gjennomført hos Oslo GK og demonstrasjonsfelt etablert hos Herning GK og Sigtuna GK (2017 -2020). Lokale frøblandinger vil bli sådd, og utvikling av botanisk sammensetning og forekomst av pollinatorer fulgt for de ulike behandlingene. Kunnskapen om de metodene vil hjelpe golfklubber med å ta gode valg for å fremme biologisk mangfold og god spillekvalitet. Resultatene vil bli presentert gjennom feltdager, populærartikler, en informasjonsvideo og en vitenskapelig artikkel.

 

Contact
Hans Martin Hanslin

Hans Martin Hanslin, The Norwegian Institute of Bioeconomy Research (NIBIO), Department of Urban Greening and Environmental Engineering, Særheim Research Centre, Postvn. 213, N-4353 Klepp St., Tel: + 47 90 50 12 79. E-mail: hans.martin.hanslin@nibio.no

FACTS
Category: Multifunctional golf facilities
Status: Finished
Project period: 2017-2020

Fundings (kSEK)

 

2017

2018

2019

2020

Total

STERF

175

200

200

200

775

Other sources

1002

1091

1085

 1196

4374

Total

1177

1291

1285

1396

5149

Objective

The aim is to provide knowledge of management strategies to enhance diversity of flowering plants and pollinators in roughs to be used in further development of multifunctional golf courses.

Specific objectives are

  • To study specific effects of sward cutting frequency, biomass removal and soil carbon addition on rough productivity and establishment of seeded target species.
  • To critically test the use of hemiparasitic Rhinanthus minor as a method to diversify roughs.
  • To assess whether cutting combined with temporal nitrogen immobilisation by incorporating carbon sources in soil improves establishment of seeded species relative to cutting only.
  • To quantify the effects of diversification measures on pollinator visiting rates and composition of the pollinator community, and relate these to the provision of resources for pollinators.
  • To evaluate how management treatments have filtering effects on sown species depending on their specific germination and establishment traits.
  • To explore the effect of management regimes on the playability of the roughs

 

Short video, talking about how to use cutting regimes, soil amendments, seed addition and hemiparasitic plants to reduce grass dominance and improve biodiversity in your roughs.