Complex Plant Cover

a plant cover formed of two or several plant associations that replace one another regularly in a small area. The formation of a complex plant cover results primarily from the heterogeneity of soil and ground-water conditions (mainly the water and salt cycle of soils), which is caused predominantly by microrelief conditions (complex plant cover of deserts) or by the uneven action of the vegetation itself on an area that was initially somewhat homogeneous (complex plant cover of marshes). Complex plant covers are classified according to the character of their structure; there are mosaic covers, zone covers, and transitional covers between the two. Sometimes (mainly when mapping vegetation on a small scale) a combination of plant associations that alternate regularly under conditions of mesorelief and even of macrorelief is called a complex plant cover. Although complex plant covers are found in all plant zones, they are especially characteristic of tundras, semideserts, and the northern parts of deserts.