Calcareous grassland (or alkaline grassland) is an ecosystem associated with thin basic soil, such as that on chalk and limestone downland. Plants on calcareous grassland are typically short and hardy, and include grasses and herbs such as trefoil. Calcareous grassland is an important habitat for insects, particularly butterflies, and is kept at a plagioclimax by grazing animals, usually rabbits. In ecology, an ecosystem is a naturally occurring assemblage of organisms (plant, animal and other living organisms—also referred to as a biotic community or biocoenosis) living together with their environment (or biotope), functioning as a unit of sorts. ... The common (Arrhenius) definition of a base is a chemical compound that either donates hydroxide ions or absorbs hydrogen ions when dissolved in water. ... For the heavy metal band see Soil (band) Soil is the layer of minerals and organic matter, in thickness from centimetres to a metre or more, on the land surface. ... The Needles, part of the extensive Southern England Chalk Formation Chalk is a soft, white, porous form of limestone composed of the mineral calcium carbonate. ... Limey shale overlaid by limestone. ... A downland is an area of open chalk upland. ... Hardy is the name of some places in the United States of America: Hardy, Arkansas Hardy, Kentucky Hardy, Virginia Hardy is also the name of the following people: Comedian Oliver Hardy (1892-1957) Novelist and poet Thomas Hardy (1840-1928) Vice-Admiral Sir Thomas Hardy (1769-1839) Vice-Admiral Sir... In popular language grass means a short, green, ground covering or lawn, usually, but not necessarily comprised of a true grass or grasses, called turf. ... Trefoil (from Latin trifolium, three-leaved plant, French trèfle, German Dreiblatt and Dreiblattbogen) is a term in Gothic architecture given to the ornamental foliation or cusping introduced in the heads of window-lights, tracery, panellings, etc. ... For other uses of the term butterfly, see butterfly (disambiguation). ... The term climax community is an outdated ecological term for a community of plants and animals which is the result of succession, where a biological system, a community, or a soil has reached a steady state. ... Grazing is the regular consumption of part of one organism without killing it by another organism. ... Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Bilateria  Acoelomorpha  Orthonectida  Rhombozoa  Myxozoa  Superphylum Deuterostomia     Chordata (vertebrates, etc. ... Genera Pentalagus Bunolagus Nesolagus Romerolagus Brachylagus Sylvilagus Oryctolagus Poelagus Rabbits are small mammals in the family Leporidae, found in many parts of the world. ...

There are large areas of calcareous grassland in northwestern Europe, particularly areas of southern England, such as Salisbury Plain and the South Downs. World map showing location of Europe A satellite composite image of Europe Europe is geologically and geographically a peninsula, forming the westernmost part of Eurasia. ... Royal motto: Dieu et mon droit (French: God and my right) Englands location within the UK Official language English de facto Capital London de facto Largest city London Area  - Total Ranked 1st UK 130,395 km² Population  - Total (2001)  - Density Ranked 1st UK 49,138,831 377/km² Religion... This article is about the plateau in southern England; Salisbury Plain is also an area on South Georgia Island. ... Near Beachy Head The South Downs is one of the two areas of chalk downland in southern England. ...