Relationships between Landscape Pattern, Wetland Characteristics, and Water Quality in Agricultural Catchments

Abstract

Water quality in streams is dependent on landscape metrics at catchment and wetland scales. A study was undertaken to evaluate the correlation between landscape metrics, namely patch density and area, shape, heterogeneity, aggregation, connectivity, land-use ratio, and water quality variables (salinity, nutrients, sediments, alkalinity, other potential pollutants and pH) in the agricultural areas of a semiarid Mediterranean region dominated by irrigated farmlands (NE Spain). The study also aims to develop wetland construction criteria in agricultural catchments. The percentage of arable land and landscape homogeneity (low value of Simpson index) are significantly correlated with salinity (r(2) = 0.72) and NO(3)-N variables (r(2) = 0.49) at catchment scale. The number of stock farms was correlated (Spearman's corr. = 0.60; p < 0.01) with TP concentration in stream water. The relative abundance of wetlands and the aggregation of its patches influence salinity variables at wetland scale (r(2) = 0.59 for Na(+) and K(+) concentrations). The number and aggregation of wetland patches are closely correlated to the landscape complexity of catchments, measured as patch density (r(2) = 0.69), patch size (r(2) = 0.53), and landscape heterogeneity (r(2) = 0.62). These results suggest that more effective results in water quality improvement would be achieved if we acted at both catchment and wetland scales, especially reducing landscape homogeneity and creating numerous wetlands scattered throughout the catchment. A set of guidelines for planners and decision makers is provided for future agricultural developments or to improve existing ones.

Relations between Retired Agricultural Land, Water Quality, and Aquatic‐Community Health, Minnesota River Basin

“…Presumably, basins with large percentage of lacustrine and palustrine features support a stronger biological community. Moreno‐Mateos et al (2008) suggested that reducing landscape homogeneity (in that example, increasing wetlands scattered throughout a basin) would lead to improved water quality. In simple terms, lacustrine and palustrine features provide more diverse habitat for organisms, so basins with more lacustrine and palustrine features should exhibit a greater aquatic‐community response.…”

Retentivity as an Indicator of the Capacity of Basins without an Outlet to Accumulate Water Surpluses

“…A significant, if not the most important on a local scale is surface runoff [38]. Geological boreholes drilled on the upland show it to consist of thick varigrained sand deposits, intercalations of till, and gravels [39]. When considering absorptive basins as sites where rainwater might be stored, it was assumed that the deposits building them had good or average permeability.…”

Integrating objectives and scales for planning and implementing wetland restoration and creation in agricultural landscapes

“…Kuusemets and Mander, 1999;Mitsch and Gosselink, 2000b;Zedler, 2003;Arheimer et al, 2004;White and Fennessy, 2005;Montreuil and Merot, 2006;Verhoeven et al, 2008). A second topic studied from a landscape perspective is the use of wetlands to improve the heterogeneity of landscapes degraded by agricultural uses as an indirect way to improve water quality and strengthen biodiversity (Comín et al, 2001;Benton et al, 2003;Moreno et al, 2007;Moreno-Mateos et al, 2008b). These studies demonstrated that the use of wetlands could reduce landscape homogeneity produced by long-standing, agricultural-intensive practices, increasing the quality of the agricultural runoff water and strengthening biodiversity.…”

“…3d and e; Mitsch and Gosselink, 2000b;Zedler, 2003;Moreno-Mateos et al, 2008b). A wider-ranging spatial distribution is a key to ensuring the establishment of stable bird populations (Whited et al, 2000), improving landscape heterogeneity (Comín et al, 2001;Benton et al, 2003) and linking hydrological and biotic connections (Verhoeven et al, 2008).…”