Grazing Vertebrates Promote Invasive Swamp Stonecrop (Crassula helmsii) Abundance

  • Published source details Dean C.E., Day J., Gozlan R.E. & Diaz A. (2015) Grazing Vertebrates Promote Invasive Swamp Stonecrop (Crassula helmsii) Abundance. Invasive Plant Science and Management, 8, 131-138


This study is summarised as evidence for the following.

Action Category

Crassula helmsii: Use grazing to control plants

Action Link
Control of Freshwater Invasive Species
  1. Crassula helmsii: Use grazing to control plants

    A replicated, controlled study in 2012–2013 on the margins of a lake in Cambridgeshire, UK (Dean et al. 2015) found that excluding grazing reduced the abundance of C. helmsii compared to grazed plots. Cover of C. helmsii in ungrazed plots decreased from approximately 95% to 60% between July 2012 and October 2013, but remained above 90% in grazed plots. The abundance and diversity of other plants was higher in ungrazed compared to grazed plots (average abundance: 97% vs 38% cover respectively; mean species diversity (Shannon-Weiner): 1.1 vs 0.88). C. helmsii also had lower proportional abundance in ungrazed compared to grazed plots (approximately 47% of total vegetation abundance vs 74%). Six 4 m2 ungrazed fenced exclosures, interspersed with six 2 m2 grazed plots, were set up in February 2012. The area was grazed by sheep in January-March 2012 and August 2012-October 2013, and by buffalo in July-December 2012. Percentage cover of C. helmsii and other plants was estimated eight times between July 2012 and October 2013.

Output references

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, terrestrial 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 17

Go to the CE Journal

Subscribe to our newsletter

Please add your details if you are interested in receiving updates from the Conservation Evidence team about new papers, synopses and opportunities.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust