Controlling invasive alien shrub species, enhancing biodiversity and mitigating flood risk: A win-win-win situation in grazed floodplain plantations.

The high nature conservation value of floodplain ecosystems is severely threatened by invasive alien species. Besides adversely affecting native biodiversity, these species also pose a major threat from a wider socio-ecological perspective (e.g. 'roughness' increases flood risk). Finding options to control dense shrub layers consisting of invasive alien species is therefore of high priority for multipurpose management. We studied cattle grazing impacts on the cover, composition and diversity of the herb and shrub layers in floodplain poplar plantations along the Tamis river, Serbia. Non-grazed, moderately grazed, intensively grazed and resting place stands were sampled in five locations in three sampling points. Non-grazed stands had substantially higher cover of invasive alien shrub species (on average 65%) than moderately and intensively grazed stands, and resting places (5.17, 0.02 and 0.00%, respectively), but without considerable differences between the grazing intensity categories. The number of invasive alien species in the shrub layer decreased considerably from non-grazed to intensively grazed stands. Species composition in the herb layer changed from non-grazed to intensively grazed stands, while resting places differed substantially from the other categories. Total species richness, richness of native generalist herbaceous grassland species, and the cover of palatable grasses were the highest in moderately and intensively grazed stands. Our results suggest that cattle grazing in floodplains is effective at controlling invasive alien shrub species. Furthermore, continuous moderate or intensive grazing would contribute to multifunctional management of invaded floodplains by enhancing local biodiversity, reducing flood risk, and providing additional grazing areas for the local community.

Plasmid-mediated quinolone resistance genes in fecal bacteria from rooks commonly wintering throughout Europe.

This study concerned the occurrence of fecal bacteria with plasmid-mediated quinolone resistance (PMQR) genes in rooks (Corvus frugilegus, medium-sized corvid birds) wintering in continental Europe during winter 2010/2011. Samples of fresh rook feces were taken by cotton swabs at nine roosting places in eight European countries. Samples were transported to one laboratory and placed in buffered peptone water (BPW). The samples from BPW were enriched and subcultivated onto MacConkey agar (MCA) supplemented with ciprofloxacin (0.06 mg/L) to isolate fluoroquinolone-resistant bacteria. DNA was isolated from smears of bacterial colonies growing on MCA and tested by PCR for PMQR genes aac(6')-Ib, qepA, qnrA, qnrB, qnrC, qnrD, qnrS, and oqxAB. All the PCR products were further analyzed by sequencing. Ciprofloxacin-resistant bacteria were isolated from 37% (392 positive/1,073 examined) of samples. Frequencies of samples with ciprofloxacin-resistant isolates ranged significantly from 3% to 92% in different countries. The qnrS1 gene was found in 154 samples and qnrS2 in 2 samples. The gene aac(6')-Ib-cr was found in 16 samples. Thirteen samples were positive for qnrB genes in variants qnrB6 (one sample), qnrB18 (one), qnrB19 (one), qnrB29 (one), and qnrB49 (new variant) (one). Both the qnrD and oqxAB genes were detected in six samples. The genes qnrA, qnrC, and qepA were not found. Wintering omnivorous rooks in Europe were commonly colonized by bacteria supposedly Enterobacteriaceae with PMQR genes. Rooks may disseminate these epidemiologically important bacteria over long distances and pose a risk for environmental contamination.