Aims Road effects from maintenance and traffic have the potential to alter plant communities,but the exact relationships between these effects and changes in plant community composition have not often been studied in ...Aims Road effects from maintenance and traffic have the potential to alter plant communities,but the exact relationships between these effects and changes in plant community composition have not often been studied in diverse environments.To determine the direction and level of community composition changes in saline environment due to road effects,we conducted a study along roads of different ages and in nearby non-road(i.e.natural)areas in the Yellow River Delta,China.Additionally,to potentially elucidate the mechanisms underlying the changes in the richness and composition of plant communities along roads,we evaluated physiochemical changes in soil of roadside and non-road areas.Methods Floristic and environmental data were collected along roadside of different ages and nearby non-road areas.To evaluate plant communities at each site,six 2 m 32 m quadrats were placed at 3-m intervals along roads and six quadrats were arranged randomly in non-road areas.To determine the difference in plant community composition betweenroadside andnon-road areas,wemeasuredspecies richness and the abundance of each species,examined species turnover and floristic dissimilarity between the two areas and positioned plant species and sites in an abstract multivariate space.Plant community(species richness,percentage of halophytes)and soil physicochemical properties(pH,salinity,moisture content,bulk density,nitrate and ammonium nitrogen concentration)were compared between roadside and non-road areas(young roadside vs.corresponding non-road areas,old roadside vs.corresponding non-road areas)by using t-tests.Classification and ordination techniques were used to examine the relationship between vegetation and related environmental variables in both roadside and non-road areas.Important Findings For both the young and old roadside areas,species richness in roadside areas was significantly higher than in non-road areas and high floristic dissimilarity values indicated that roadside and non-road areas differed greatly in community composition.In both the young and old roadside areas,the plant communities in roadside areas had lower percentages of halophytes than non-road communities.Correspondence analysis and two-way indicator species analysis showed that halophytes dominated in the non-road areas,while a number of typical non-salt-tolerant species dominated in the roadside areas.Compared to non-road areas,activities associated with roads significantly decreased soil moisture,bulk density and salinity and increased soil pH and nitrate content.Forward selection for the environmental variables in canonical correspondence analysis showed that soil salinity was the most important factor related to the variation of species composition between roadside and non-road areas.Our study demonstrates that road effects have a significant impact on the associated vegetation and soil,and these changes are consistent across roads of different ages in our system.展开更多
Roads affect wildlife significantly through direct mortality but also through behavioral change. We explored the ef- fects of unsurfaced sand roads with a low traffic volume on the travelling behavior of gopher tortoi...Roads affect wildlife significantly through direct mortality but also through behavioral change. We explored the ef- fects of unsurfaced sand roads with a low traffic volume on the travelling behavior of gopher tortoises Gopherus polyphemus in scrub habitat in central Florida, as evidenced by the tracks left by tortoises on sand roads. Tortoises （and most other taxa leaving tracks on the roads） did not appear to make use of roads for travel but attempted to cross them, the success of which was influ- enced by the size of the individual. Smaller animals （presumably younger tortoises） were more challenged than larger animals by both sand road widths and depths of vehicle ruts in sand roads. Sand roads may present both physical and physiological challenges to gopher tortoises, particularly to small ones. This research provides further evidence that the negative influence of roads in fragmenting the environment is not limited to vehicle mortality [Current Zoology 61 （4）： 578-585, 2015].展开更多
Road salts are frequently used for deicing of roads in the Nordic countries. During snow-melt, the road run-off containing high concentrations of road salt and various metals such as Cu remobilized from sand, silt and...Road salts are frequently used for deicing of roads in the Nordic countries. During snow-melt, the road run-off containing high concentrations of road salt and various metals such as Cu remobilized from sand, silt and dust may negatively influence organisms in downstream receiving water bodies. The present work focuses on the impact of road salt（NaCl） and Cu, separately and in mixtures on Atlantic salmon alevins from hatching till swim-up. The results showed that high road salt concentrations could induce a series of negative effects in alevins such as reduced growth, deformities, delayed swim-up and mortality. For alevins exposed to all tested road salt concentrations（100–1000 mg/L）,mortality was significantly higher compared to control. In exposure to Cu solutions（5–20 μg Cu/L）, no effects on growth, morphology, swim-up or mortality of alevins compared to control were observed. In mixture solutions（road salt and Cu）, ultrafiltration of the exposure water demonstrated that only 20%–40% of Cu was present as positively charged low molecular mass（LMM） Cu species assumed to be bioavailable. When exposed to road salt and Cu mixtures, negative effects in alevins such as reduced growth, deformities,delayed swim-up and mortality were observed. The overall results indicated that the road salt application could seriously affect sensitive life stages of Atlantic salmon, and application of road salt should be avoided during the late winter–early spring period.展开更多
Noise, an obvious effect of urbanization, has a negative impact on animal vocalizations and the hunting efficiency of acoustic predators. However, the influence of noise pollution on the spatial distribution of popula...Noise, an obvious effect of urbanization, has a negative impact on animal vocalizations and the hunting efficiency of acoustic predators. However, the influence of noise pollution on the spatial distribution of populations remains understudied. The aim was to assess the factors shaping the distribution pattern of an acoustic predator （long-eared owl Asio otus） in an urban-farmland matrix. We hypothesized that the probability of an acoustic predator occurring decreases with growing nocturnal noise emission. This owl survey was conducted in Krak6w （S Poland） on 79 ran- domly selected sample plots （1 km x 1 km）. Six habitat variables （area of parks, woodlands, grass- land, arable land, habitat diversity index, and noise pollution） were identified and correlated with the probability of the species＇ occurrence. Proximity to pedestrian routes and roads, habitat frag- mentation, and noise intensity was also defined at nest sites and random sites. Long-eared owls occurred on 37% of the sample plots. Occupied plots had a greater area of grassland and arable land as well as a lower level of noise pollution than the unoccupied ones. A multivariate model revealed that area of grassland and nocturnal noise emission was significantly correlated with the probability of long-eared owls occurring and that the high probability of occurrence recorded on plots with large areas of grassland was reduced by noise pollution. The noise intensity recorded at nest sites was also significantly lower than at random sites. This study suggests that apart from habitat factors, the distribution of acoustic predators in an urban matrix is driven by noise pollu- tion. This highlights the importance of proper landscape management, that is, maintaining large grassland areas and preventing noise from increasing within them.展开更多
基金National Basic Research Program of China(2010CB950602,2006CB403305)Natural Science Foundation of China(30870409)National Key Technology R&D Program(2010BAK69B15).
文摘Aims Road effects from maintenance and traffic have the potential to alter plant communities,but the exact relationships between these effects and changes in plant community composition have not often been studied in diverse environments.To determine the direction and level of community composition changes in saline environment due to road effects,we conducted a study along roads of different ages and in nearby non-road(i.e.natural)areas in the Yellow River Delta,China.Additionally,to potentially elucidate the mechanisms underlying the changes in the richness and composition of plant communities along roads,we evaluated physiochemical changes in soil of roadside and non-road areas.Methods Floristic and environmental data were collected along roadside of different ages and nearby non-road areas.To evaluate plant communities at each site,six 2 m 32 m quadrats were placed at 3-m intervals along roads and six quadrats were arranged randomly in non-road areas.To determine the difference in plant community composition betweenroadside andnon-road areas,wemeasuredspecies richness and the abundance of each species,examined species turnover and floristic dissimilarity between the two areas and positioned plant species and sites in an abstract multivariate space.Plant community(species richness,percentage of halophytes)and soil physicochemical properties(pH,salinity,moisture content,bulk density,nitrate and ammonium nitrogen concentration)were compared between roadside and non-road areas(young roadside vs.corresponding non-road areas,old roadside vs.corresponding non-road areas)by using t-tests.Classification and ordination techniques were used to examine the relationship between vegetation and related environmental variables in both roadside and non-road areas.Important Findings For both the young and old roadside areas,species richness in roadside areas was significantly higher than in non-road areas and high floristic dissimilarity values indicated that roadside and non-road areas differed greatly in community composition.In both the young and old roadside areas,the plant communities in roadside areas had lower percentages of halophytes than non-road communities.Correspondence analysis and two-way indicator species analysis showed that halophytes dominated in the non-road areas,while a number of typical non-salt-tolerant species dominated in the roadside areas.Compared to non-road areas,activities associated with roads significantly decreased soil moisture,bulk density and salinity and increased soil pH and nitrate content.Forward selection for the environmental variables in canonical correspondence analysis showed that soil salinity was the most important factor related to the variation of species composition between roadside and non-road areas.Our study demonstrates that road effects have a significant impact on the associated vegetation and soil,and these changes are consistent across roads of different ages in our system.
文摘Roads affect wildlife significantly through direct mortality but also through behavioral change. We explored the ef- fects of unsurfaced sand roads with a low traffic volume on the travelling behavior of gopher tortoises Gopherus polyphemus in scrub habitat in central Florida, as evidenced by the tracks left by tortoises on sand roads. Tortoises （and most other taxa leaving tracks on the roads） did not appear to make use of roads for travel but attempted to cross them, the success of which was influ- enced by the size of the individual. Smaller animals （presumably younger tortoises） were more challenged than larger animals by both sand road widths and depths of vehicle ruts in sand roads. Sand roads may present both physical and physiological challenges to gopher tortoises, particularly to small ones. This research provides further evidence that the negative influence of roads in fragmenting the environment is not limited to vehicle mortality [Current Zoology 61 （4）： 578-585, 2015].
文摘Road salts are frequently used for deicing of roads in the Nordic countries. During snow-melt, the road run-off containing high concentrations of road salt and various metals such as Cu remobilized from sand, silt and dust may negatively influence organisms in downstream receiving water bodies. The present work focuses on the impact of road salt（NaCl） and Cu, separately and in mixtures on Atlantic salmon alevins from hatching till swim-up. The results showed that high road salt concentrations could induce a series of negative effects in alevins such as reduced growth, deformities, delayed swim-up and mortality. For alevins exposed to all tested road salt concentrations（100–1000 mg/L）,mortality was significantly higher compared to control. In exposure to Cu solutions（5–20 μg Cu/L）, no effects on growth, morphology, swim-up or mortality of alevins compared to control were observed. In mixture solutions（road salt and Cu）, ultrafiltration of the exposure water demonstrated that only 20%–40% of Cu was present as positively charged low molecular mass（LMM） Cu species assumed to be bioavailable. When exposed to road salt and Cu mixtures, negative effects in alevins such as reduced growth, deformities,delayed swim-up and mortality were observed. The overall results indicated that the road salt application could seriously affect sensitive life stages of Atlantic salmon, and application of road salt should be avoided during the late winter–early spring period.
文摘Noise, an obvious effect of urbanization, has a negative impact on animal vocalizations and the hunting efficiency of acoustic predators. However, the influence of noise pollution on the spatial distribution of populations remains understudied. The aim was to assess the factors shaping the distribution pattern of an acoustic predator （long-eared owl Asio otus） in an urban-farmland matrix. We hypothesized that the probability of an acoustic predator occurring decreases with growing nocturnal noise emission. This owl survey was conducted in Krak6w （S Poland） on 79 ran- domly selected sample plots （1 km x 1 km）. Six habitat variables （area of parks, woodlands, grass- land, arable land, habitat diversity index, and noise pollution） were identified and correlated with the probability of the species＇ occurrence. Proximity to pedestrian routes and roads, habitat frag- mentation, and noise intensity was also defined at nest sites and random sites. Long-eared owls occurred on 37% of the sample plots. Occupied plots had a greater area of grassland and arable land as well as a lower level of noise pollution than the unoccupied ones. A multivariate model revealed that area of grassland and nocturnal noise emission was significantly correlated with the probability of long-eared owls occurring and that the high probability of occurrence recorded on plots with large areas of grassland was reduced by noise pollution. The noise intensity recorded at nest sites was also significantly lower than at random sites. This study suggests that apart from habitat factors, the distribution of acoustic predators in an urban matrix is driven by noise pollu- tion. This highlights the importance of proper landscape management, that is, maintaining large grassland areas and preventing noise from increasing within them.
