Calcareous grassland (or alkaline grassland) is an ecosystem associated with thin basicsoil, such as that on chalk and limestonedownland.[1] Plants on calcareous grassland are typically short and hardy, and include grasses and herbs such as clover. Calcareous grassland is an important habitat for insects, particularly butterflies and ants,[2] and is kept at a plagioclimax by grazinganimals, usually sheep and sometimes cattle. Rabbits used to play a part but due to the onset of myxomatosis their numbers decreased so dramatically that they no longer have much of a grazing effect.
The machair forms a different kind of calcareous grassland, where fertile low-lying plains are formed on ground that is calcium-rich due to shell sand (pulverised sea shells).
Gibson, C.W.D. (1995). Chalk grasslands on former arable land: a review. Bioscan (UK) Ltd, Oxford.
Gibson, C.W.D. & Brown, V.K. (1991). The nature and rate of development of calcareous grassland in southern Britain. Biological Conservation, 58, 297-316.
Mugnai M, Frasconi Wendt C, Balzani P, Ferretti G, Dal Cin M, Masoni A, Frizzi F, Santini G, Viciani D, Foggi B, Lazzaro L. (2021). Small-scale drivers on plant and ant diversity in a grassland habitat through a multifaceted approach. PeerJ 9:e12517 https://doi.org/10.7717/peerj.12517
