Crop rotational diversity can mitigate climate-induced grain yield losses.

Diversified crop rotations have been suggested to reduce grain yield losses from the adverse climatic conditions increasingly common under climate change. Nevertheless, the potential for climate change adaptation of different crop rotational diversity (CRD) remains undetermined. We quantified how climatic conditions affect small grain and maize yields under different CRDs in 32 long-term (10-63 years) field experiments across Europe and North America. Species-diverse and functionally rich rotations more than compensated yield losses from anomalous warm conditions, long and warm dry spells, as well as from anomalous wet (for small grains) or dry (for maize) conditions. Adding a single functional group or crop species to monocultures counteracted yield losses from substantial changes in climatic conditions. The benefits of a further increase in CRD are comparable with those of improved climatic conditions. For instance, the maize yield benefits of adding three crop species to monocultures under detrimental climatic conditions exceeded the average yield of monocultures by up to 553 kg/ha under non-detrimental climatic conditions. Increased crop functional richness improved yields under high temperature, irrespective of precipitation. Conversely, yield benefits peaked at between two and four crop species in the rotation, depending on climatic conditions and crop, and declined at higher species diversity. Thus, crop species diversity could be adjusted to maximize yield benefits. Diversifying rotations with functionally distinct crops is an adaptation of cropping systems to global warming and changes in precipitation.

Effects of proximity to stormwater on the sandy-beach macrofaunal assemblages of metropolitan Adelaide, South Australia.

Stormwater run-off often enters coastal zones but its effects on sandy beaches are unknown. This study aimed to investigate associations between macrofaunal assemblages and proximity to stormwater outlets along Adelaide's beaches, comparing semi-natural creeks with concrete drains. Five positions along an increasing-salinity gradient were sampled in the intertidal zone of six stormwater outlets and also at corresponding control sites. There was no significant difference between the two forms of stormwater (semi-natural creeks with concrete drains). Only the largest outlet (Torrens) had a significant difference in assemblage structure and taxon richness compared to its control. Total abundances at this outlet followed a convex pattern across the salinity gradient, so it appears that flow there may have a spatially-limited positive effect on the macrofauna in terms of increasing abundance and richness. Therefore, the hypothesised detrimental effects of stormwater have not been found to be evident and these observed patterns warrant further investigation.