How Surface Water Management Can Benefit Fish Conservation in Urban Streams

We analyzed 33 y of fish community data collected from a low-order, urban stream in central Illinois, USA, to determine the effects of municipal wastewater management projects and urbanization on fish communities. From 1985 to 2017, species richness, number of pollution-intolerant species, and alternative index of biotic integrity significantly increased at sites across this system. Species diversity likewise increased, but was mostly significant only at sites downstream of the effluent outflow. Ceasing the chlorination of wastewater in 1990 resulted in significant increases in fish community metrics both upstream and downstream of effluent outflow, although effects varied from site to site. Completing a combined sewer overflow abatement project in 2008 resulted in some significant increases in species richness, diversity, and number of pollution-intolerant species at sites downstream of effluent outflow. From 2001 to 2016, the change in the number of pollution-intolerant species correlated inversely with the increased percentage of impervious cover in the study system. There was no significant correlation of other metrics with the change in percent impervious surfaces. These results suggest that urbanization at upstream sites limited to some extent the benefits of water management interventions that improved fish community metrics at downstream sites.

Can Moderate Heavy Metal Soil Contaminations Due To Cement Production Influence The Surrounding Soil Bacterial Communities?

Events of soil contamination by heavy metals are mostly related to human activities that release these metals into the environment as emissions or effluents. Among the industrial activities related to heavy metal pollution, cement production plants are considered one of the most common sources. In this work we applied the HTS molecular approach called 16S rDNA metabarcoding to perform the taxonomic characterization of the prokaryotic communities of the soil surrounding three cement plants as well as two areas outside the influence of the cement plants that represented agricultural production environments free of heavy metal contamination (control areas). We applied the environmental genomics approaches known as “structural community metrics” (α- and β-diversity metrics) and “functional community metrics” (PICRUSt2 approach) to verify whether or not the effects of heavy metal contamination in the study area generated impacts on soil bacterial communities. We found that the impact related to the elevation of heavy metal concentration due to the operation of cement plants in the surrounding soil can be considered smooth according to globally recognized indices such as Igeo. However, we identified that both the taxonomic and functional structures of the communities surrounding cement plants were different from those found in the control areas. We consider that our findings contribute significantly to the general understanding of the effects of heavy metals on the soil ecosystem by showing that light contamination can disturb the dynamics of ecosystem services provided by soil, specifically those associated with microbial metabolism.

Can the Stream Quantification Tool (SQT) Protocol Predict the Biotic Condition of Streams in the Southeast Piedmont (USA)?

In some states, the Stream Quantification Tool (SQT) has been adopted to quantify functional change of stream mitigation efforts. However, the ability of the SQT protocol to predict biological function and uphold the premise of the Stream Functions Pyramid (Pyramid) remains untested. Macroinvertebrate community metrics in 34 headwater streams in Piedmont, North Carolina (NC, USA) were related to NC SQT protocol (version 3.0) factors and other variables relevant to ecological function. Three statistical models, including stepwise, lasso, and ridge regression were used to predict the NC Biotic Index (NCBI) and Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness using two datasets: 21 SQT variables and the SQT variables plus 13 additional watershed, hydraulic, geomorphic, and physicochemical variables. Cross-validation revealed that stepwise and ridge outperformed lasso, and that the SQT variables can reasonably predict biology metrics (R2 0.53–0.64). Additional variables improved prediction (R2 0.70–0.88), suggesting that the SQT protocol is lacking metrics important to macroinvertebrates. Results moderately support the Pyramid: highly predictive ridge models included metrics from all levels, while highly predictive stepwise models included metrics from higher levels, and not watershed hydrology. Reach-scale metrics were more important than watershed hydrology, providing encouragement for projects limited by watershed condition.

Snakes and the Eternal City: variation in community metrics, body size and population density of snakes in contrasted landscapes of suburban Rome (Italy)

Reports of global declines in animal populations are now numerous and also include snakes, a group of animals now widely regarded as bio indicators. A prerequisite for any conservation management plan to protect or restore snake populations requires a data base that provides insight into population composition and changes. However, snakes are well known to be particularly difficult to quantitatively sample due to their secretive and elusive nature, and hence accumulating an adequate database for analysis requires long-term field studies that involve intensive searches. Populations of four snake species, Zamensis longissimus, Natrix helvetica, Vipera aspis and Hierophis viridiflavus living in two suburban areas of Rome with different extents of habitat alteration (deforestation), Vejo, a less altered site, and Tor Bella Monaca, a high altered site, have been monitored, but with interruptions since 1995. The results indicated that H. viridiflavus was the commonest species at both sites. Male bias was found in all four species but especially in Z. longissimus and V. aspis with detection of juveniles greatest in H. viridiflavus and N. helvetica. Snout to vent lengths (SVL) of H. viridiflavus and Z. longissimus, which were present at both sites, were greater at the less degraded habitat of the two study localities. Community metrics indicated that the degraded habitat had lower species richness, evenness, Shannon and Simpson diversity indices, but a higher dominance index. Recapture frequencies of snakes recaptured either once or multiple times were in general greater at Vejo. The highest population densities were found in H. viridiflavus, followed by V. aspis and N. helvetica, which were similar. However, long term trends in densities show declines in V. aspis and N. helvetica between 1995 and 2019. Population densities were in good agreement with density estimates found in previous studies of snakes in more natural habitats.

Differential effects of farming practice on cuckoo bumblebee communities in relation to their hosts

ABSTRACTBees are important for vital pollination of wild and crop plants, but are in decline worldwide. Intensification of agriculture is a major driver of bee decline. Organic farming practices are designed to limit environmental impacts of agriculture and can increase bee abundance and species diversity. However, studies have been heavily focused towards some guilds of bees, overlooking others. This includes social brood parasites, cuckoo bumblebees, an understudied bee lineage. Little is known about bumblebee host and cuckoo population dynamics, and the effects of farming practice on cuckoo bumblebees have never previously been evaluated.To compare the effects of farming practice (organic vs conventional) on the abundance, species diversity, and community dissimilarity of cuckoo bumblebees and their hosts, we compared host and cuckoo community metrics across ten matched pairs of organic and conventional farms in Yorkshire, UK.As found by many previous studies, host bumblebees were more abundant on organic farms than on conventional farms. Despite this, cuckoo bumblebees were equally abundant on both farm types. Contrary to prediction, community dissimilarity and species diversity were unaffected by farm type for both host and cuckoo communities.Synthesis and applications: Results suggest that cuckoo bumblebee community metrics are not solely driven by host community metrics, and that cuckoos may respond differently from their hosts to differences among farming practices. This could, in turn, indicate that a unified management practice is not sufficient to conserve all bumblebee species.