[Landscape pattern and its functioning after ecological reconstruction in black soil of northern China]

Taken Baiquan County in Heilongjiang Province as a case, this paper studied the effects of regional ecological reconstruction on agricultural landscape pattern and its functioning in soil and water conservation, with the spatial expression and quantity identification investigated based on Geographic Information System (GIS) and field data. The landscape pattern index in class scale, transition matrix of landscape elements, macrostructure of shelter-belt networks, and spatial distribution and hydrological characteristic of reservoirs and ponds in 1989 and 2002, as well as the effects of landscape pattern and its spatial configuration change on soil and water loss were compared. The results showed that artificial ecological reconstruction changed the quantity and spatial configuration of landscape patterns in regional scale, and exerted a significant effect on soil and water conservation. From 1989 to 2002, farmland area reduced 24 731.01 hm2, while forest land, grassland and water area increased 11 728.56, 1838.97 and 1190.97 hm2, respectively. The controlled eroded land increased by 55%, and the shelterbelt-protected farmland increased by 82.2%. The number and storage capacity of reservoirs and ponds added up to 1 490 and 2.4 x 10(8) m3, respectively, and 43.7% of intercepted surface runoff of whole landscape was collected.