Study

Control of Scot's broom (Cytisus scoparius (L.) Link.): the relative conservation merits of pulling versus cutting

  • Published source details Ussery J.G. & Krannitz P.G. (1998) Control of Scot's broom (Cytisus scoparius (L.) Link.): the relative conservation merits of pulling versus cutting. Northwest Science, 72, 268-273.

Summary

Over the last 150 years in the pacific northwest of Canada and USA, agricultural and urban development has led to the loss of most Garry oak Quercus garryana ecosystems. These ecosystems are biologically rich and characterized by a mosaic of woodlands, meadows, grasslands and open rocky areas. Overgrazing by domestic and feral livestock has impaired Garry oak regeneration and this, coupled with fire suppression, has enabled non-native plant species such as Scot's broom Cytisus scoparius and orchard grass (or cock's-foot) Dactylis glomerata to take over. In British Columbia, only 1-5% of original Garry oak ecosystems are left and much of this has been strongly modified by invasive species.

A study was undertaken to investigate how the method and timing of the removal of the invasive shrub, Scot's broom, affected the level of site disturbance and subsequent broom regeneration from seed and resprouting in areas of remnant Garry oak meadow communities in Victoria, British Columbia.

Study site: The study was undertaken in remnant, high conservation value, Garry oak Quercus garryana meadow communities at the southern tip of Vancouver Island around the town of Victoria, southwest British Columbia.

Manual uprooting versus cutting: Manual uprooting versus cutting of invasive broom Cytisus scoparius was compared at two time periods, in May when the shrub was in flower, and in July just prior to seed dispersal. Pulled and cut material was removed from site for disposal.

Soil disturbance, trampling & seedling regeneration: Soil disturbance, trampling, and seedling regeneration were significantly higher in plots where broom plants were uprooted as compared to plots where broom plants were cut at the base. The amount of trampling damage to meadow plants was higher in July than in May, howevr, in July the trampled plants comprised mostly exotic grasses, while in May these included flowering and fruiting stalks of native plants such as common camas Camassia quamash.

Resprouting of cut broom stems: Resprouting of cut broom stems was observed in only seven (9%) of the 75 broom stems cut and all of these died-back within one year.

Conclusions: These results suggest that the preferred broom removal strategy in Garry oak meadow communities of high conservation value is to cut broom after native herbaceous species have flowered and set seed. This approach will minimize damage to native vegetation and should reduce the amount of broom seedling regeneration in the longterm if cutting is regularly repeated.


Note: If using or referring to this published study, please read and quote the original paper. Please do not quote as a www.conservationevidence.com case as this is for previously unpublished work only.

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust