A Regression Model of Stream Water Quality Based on Interactions between Landscape Composition and Riparian Buffer Width in Small Catchments

Martins

WIT Transactions on Ecology and the Environment

et al. 2020

Self Cite

Due to intense industrial and urban activity Ave River Basin, Portugal was once tagged as one of the most polluted in Europe. Besides point source pressures are the most evident threat to water quality in this river basin, in the present study, the effect of landscape on water quality was analysed. From a hydrological database, the concentration surface water parameters was extracted, comprehended between 1988 and 2016. The average concentrations in each sampling site for each hydrological year was calculated. The averages were correlated to 15 landscape metrics by using the Spearman's rank correlation coefficient, over the analysed hydrological years. For each landscape metric, the percentage of correlations with surface water parameters for each hydrological year that had statistical significance (p≤0.05) was counted, and the same analysis was made for each surface water parameter. The area occupied by artificial surfaces increased the contaminant concentrations in 65.3% of the correlations while the edge density increased by 62%. For forested areas, the edge density and occupied area had, respectively, 56.0% and 66.0%, of correlations that decreased contaminant concentrations. Conductivity was the parameter that has most linked to landscape metrics since, 52% increased the concentration, 21% decreased, while the remaining 27% did not have statistical significance. Oxygen demands, total suspended solids, different nitrates forms, total orthophosphate and coliforms were acceptably correlated, with percentages ranging from 20% to 44%. Only heavy metals were poorly correlated, since the percentage of correlations that varied the concentrations was lower than 8%. This study allowed us to understand that in an urbanised river basin, where point source pressures are the dominant pollution source, landscape metrics also have an effect on water quality and can become a threat to hydric resources.

Section: Discussionsupporting

confidence: 56%

Effect of Landscape Metrics on Water Quality Over Three Decades: A Case Study of the Ave River Basin, Portugal

Martins

WIT Transactions on Ecology and the Environment

et al. 2020

Self Cite

“…These results are quite similar to a particular study where the effect of agriculture combined with forested land uses effects explain water quality variations, enhanced than when these variables are used alone [49]. Such results prove that sustainable agriculture can not harm, but even, improve water quality when combined with forested land uses, as barriers of contamination from runoff or soil erosion.…”

Section: Resultssupporting

confidence: 84%

Exploring the Effects of Landscape Metrics in Water Quality, Ave River Basin Case Study

Fernandes¹,

Martins²,

Fernandes³

et al. 2020

IJDNE

Ave River Basin, located in the northern region of Portugal, was once tagged as one of the most polluted of Europe. Although many authors have given prominence to point source pressures, the present study reveals challenging results, by exposing strong effects of landscape metrics in water quality. In twelve sampling sites, the Portuguese benthic macroinvertebrate index (IPtIN) was measured during the winter and summer of 2017. For each site, it was delineated drainage sections, ranging from 100 meters to the entire drainage area. For each section, it was calculated landscape metrics for generic land-use types, and it was also calculated the Spearman's rank correlation coefficient, between each metric in each scale with IPtIN. The preliminary analysis of results led to understand during the winter edge length and number of patches of artificial surfaces revealed a negative impact. Variables such as connectance of agricultural land use patches only revealed a negative influence during summer, in a short-range spatial extent. The contrast between agricultural land uses with forested and with artificial areas was the metric with a notable effect, since maximum correlations were achieved for the contrast between forested and agriculture, and minimum in the contrast between agriculture with artificial areas.

“…In the Brazilian territory, the competition between conservation of native vegetation and agro-industrial activities has caused deforestation [24][25][26]. Frequently, the competition evolves to severe land use conflicts, because the expansion of productive areas reduces the system's capacity to conserve vital services, namely those related to water resources in river basins [27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

The Configuration of Forest Cover in Ribeirão Preto: A Diagnosis of Brazil’s Forest Code Implementation

et al. 2020

Self Cite

The fragmentation of forests is a consequence of human activities that intensively change the natural landscapes. In Brazil, there is a long-standing legal framework for native vegetation protection, called Forest Code. The last update is from 2012. The revisions incorporated in this restructured code (Law No. 12,651/12) encompassed new rules, rights and obligations for adequate land use management of productive systems and for environmental conservation and protection. An example of a protective measure was the creation of a Legal Reserve inside the rural properties and Areas of Permanent Protection around the watercourses. This study explored the effects of implementing the new code on the spatial and temporal evolution of forest cover fragmentation since the legal changes were set up. In that context, the area, perimeter and shape (circularity index) of forest fragments, as well as the buffer strips along watercourses, were assessed from 2010 to 2016 within the municipality of Ribeirão Preto, São Paulo state, Brazil. The assessment resorted to remote sensing techniques and visual inspection of orbital images. It was clear from the results that forest patches became more abundant but smaller, more dispersed and elongated, and that this route to fragmentation was hinged on a chaotic expansion of urban and agricultural areas. Important edge effects were anticipated from these results. The area numbers revealed that Ribeirão Preto was 7.95% covered with forest fragments in 2010, while this percentage rose to 8.03% in 2013 and reached 8.35% in 2016. Most of this increase occurred within a 30-meter wide buffer along the watercourses. This was a positive outcome. However, the numbers also revealed that forested areas smaller than 51 hectares increased from 71% in 2010 to 73% in 2016. The conclusions were that implementation of Law No. 12,651/12 is leading to an increase of forestland, but not yet promoting sustainability, namely through improved connectivity among fragments for reduction of edge effects and provision ecosystem services.