et al. , 2002). A study in Canada found that Common Terns Sterna hirundo nested at higher densities in sites where clumps of mossy stonecrop and driftwood had been added, while they rarely nested in sites layered with gravel or with bare ground. At a site in the UK, the number of Ringed Plover Charadrius hiaticula , Oystercatcher Haematopus ostralegus and Lapwing doubled after vegetation was removed from an area of 465 m 2 (Wilson, 2005). Studies from islands have found higher abundances of birds when vegetation is removed (Akers & Allcorn, 2006), or when vegetation is sparse (Burgess & Hirons, 1992). One study found that Sooty Terns Sterna fuscata did not nest when all vegetation was cleared, but did nest when vegetation was partially cleared (Saliva & Burger, 1989). Saunders’s Gulls Saundersilarus saundersi at Shuangtaizehekou NNR, Liaoning, China, nested in areas where tall (around 1 m) dead stems of Suaeda salsa from the previous growing season had been cleared overwinter, but avoided areas where stems remained. Winter clearance of vegetation has continued at the reserve for >20 years (David Melville, pers. comm.).
Shorebirds often prefer to roost in open spaces, such as these Sharp-tailed sandpipers Calidris acuminata roosting in a salt marsh in Goolwa, South Australia. [Credit: Micha V. Jackson].
3. Factors that can affect outcomes
Water level: Water depth influences how much and what type of vegetation will grow. Some evidence suggests that bird abundance is more strongly related to the water level than it is to vegetation (Bancroft et al. , 2002), therefore water level should be considered alongside vegetation management.
4. Implementation
Manual removal: Vegetation can be cleared physically by hand or by using machinery. Heavy machinery can be used to scrape away vegetation, remove woody debris and clear vegetation, for example bulldozers (Roby et al. , 2002) or tractors (Wilson, 2005) can be used to create bare sand. Machinery may then be used to smooth bare sand surface to create attractive nesting habitat (Roby et al. , 2002).
Flooding: Vegetation can also be suppressed by flooding. Flooding benefits the macroinvertebrates in the mud, so when water is drained, they are readily available as food for
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