Spatio-temporal changes of road traffic noise pollution at ecoregional scale.

Noise pollution is a pervasive factor that increasingly threatens natural resources and human health worldwide. In particular, large-scale changes in road networks have driven shifts in the acoustic environment of rural landscapes during the past few decades. Using sampling plots from the Spanish Landscape Monitoring System (SISPARES), 16 km2 each, we modelled the spatio-temporal changes in road traffic noise pollution in Ecoregion 1 of Spain (approximately 66,000 km2). We selected a study period that was characterised by significant changes in the size of the road network and the vehicle fleet (i.e. between 1995 and 2014) and used standard and validated acoustic computation methods for environmental noise modelling (i.e. European Directive, 2002/49/EC) within sampling plots. We then applied a multiple linear regression to expand noise modelling throughout the whole of Ecoregion 1. Our results showed that the noise level increased by 1.7 dB(A) in average per decade in approximately 65% of the territory, decreased by 1.3 dB(A) per decade in about 33%, and remained unchanged in 2%. This suggests that road traffic noise pollution levels may not grow homogeneously in large geographical areas, maybe due to the concentration of large fast traffic flows on modern motorways connecting towns. Our research exemplifies how landscape monitoring systems such as cost-effective approaches may play an important role when assessing spatio-temporal patterns and the impact of anthropogenic noise pollution at large geographical scales, and even more so in a global context of constricted resources and limited availability of historical data on traffic and environmental noise monitoring.

Changes and drivers in Spanish landscapes at the Rural-Urban Interface between 1956 and 2018.

This paper presents unique comprehensive quantitative measures of the changes in Spanish rural landscapes, specifically in relation to the Rural-Urban Interface (RUI). Our objective was to investigate the urbanisation process in rural areas of Spain, thus the expansion of the RUI in an environmentally complex study area (it includes arid regions, continental areas or high mountains). The data were produced by the Spanish Rural Landscapes Monitoring System project (SISPARES), which has carried out five separate surveys for 1956, 1984, 1998, 2008 and 2018. SISPARES data provide RUI quantification by identifying urban patches, using aerial images, in a permanent network of 206 stratified random landscape sampling units (4 × 4 km each) deliberately located in rural areas. The cost-effective and spatio-temporal SISPARES approach enables the production of landscape geographical models at each survey date and the modelling of its evolution over each time period. We hypothesised that the RUI expansion did not follow a homogeneous spatio-temporal pattern, and therefore neither did the drivers responsible for it. Building on SISPARES data, we evaluated through CART analyses the relationship of RUI expansion with relevant environmental and anthropogenic driving factors, such as climate, bedrock, landscape composition and human population density. The historical narrative perspective was also used to aid discussion of the results. Historically, Spain contained few areas of RUI, but major changes were determined in the initial study period (1956-1984), which conformed a seminal geographic pattern for subsequent RUI increment. In contrast, the RUI expansion did not increase greatly during the following periods, between 1984 and 2018. The RUI expansion has been primarily driven by anthropogenic factors, constrained by the environmental characteristics of Spain. The expansion pattern is likely to has shifted from a national scale in the 1950s, to a continental scale at later dates as the result of the changes in socio-political scenarios.