Effects of two submerged macrophyte species on microbes and metazoans in rooftop water-storage ponds with different labile carbon loadings.

Nature-based solutions including rooftop-water storage ponds are increasingly adopted in cities as new eco-designs to address climate change issues, such as water scarcity and storm-water runoff. Macrophytes may be valuable additions for treating stored rooftop waters and provisioning other services, including aquaponics, esthetic and wildlife-conservation values. However, the efficacy of macrophyte treatments has not been tested with influxes of different labile carbon loadings such as those occurring in storms.

Diseased fish in the freshwater trade: from retailers to private aquarists.

Millions of fish are transported between countries annually for the aquarium trade, yet no quantitative study has examined how disease frequency differs among species and stakeholders. Here we visually inspected freshwater fish species in 12 specialised and non-specialised aquarium retailers in Spain for the presence of diseased fish in 2015 and in 2016. This information was complemented with disease records from 3 internet fora (>100000 users) and pathogen identification at a retailer.

Water-quality impacts in semi-arid regions: can natural 'green filters' mitigate adverse effects on fish assemblages?

The effective aridity in riparian areas is increasing from climate change and from human water consumption, which exacerbates the impacts of effluents from wastewater-treatment plants and from catchment run-off in rivers. The potential of natural riparian areas to act as 'green filters' has long been recognized, but the possible ecological benefits of natural riparian areas over large-scale environmental gradients on fish have not been explored in detail. Using an extensive data-set from northeastern Spain (99,700 km, 15 catchments, 530 sites), ours is the first study to ask whether natural riparian vegetation can mitigate the effects of pollution on fish in rivers experiencing water scarcity.

Environmental correlates of food-chain length, mean trophic level and trophic level variance in invaded riverine fish assemblages.

Examining how the trophic structure of biotic assemblages is affected by human impacts, such as habitat degradation and the introduction of alien species, is important for understanding the consequences of such impacts on ecosystem functioning. We used general linear mixed models and hierarchical partitioning analyses of variance to examine for the first time the applicability of three hypotheses (ecosystem-size, productivity and disturbance) for explaining food-chain length (FCL) in invaded fish assemblages. We used Fishbase trophic level (TL) estimates for 16 native and 18 alien fish species in an extensive riverine system in north-eastern Spain (99,700 km, 15 catchments, 530 sites).