Landscape and local habitat traits moderate wild bee communities. However, whether landscape effects differ between local habitat types is largely unknown.
Objectives
We explored the way that wild bee communities in three distinct habitats are shaped by landscape composition and the availability of flowering plants by evaluating divergences in response patterns between habitats.
Methods
In a large-scale monitoring project across 20 research areas, wild bee data were collected on three habitats: near-natural grassland, established flower plantings and residual habitats (e.g. field margins). Additionally, landscape composition was mapped around the research areas.
Results
Our monitoring produced a dataset of 27,650 bees belonging to 324 species. Bee communities on all three habitats reacted similarly to local flower availability. Intensively managed grassland in the surrounding landscape had an overall negative effect on the studied habitats. Other landscape variables produced diverging response patterns that were particularly pronounced during early and late season. Bee communities in near-natural grassland showed a strong positive response to ruderal areas. Flower plantings and residual habitats such as field margins showed a pronounced positive response to extensively managed grassland and woodland edges. Response patterns regarding bee abundance were consistent with those found for species richness.
Conclusion
We advise the consideration of local habitat type and seasonality when assessing the effect of landscape context on bee communities. A reduction in the intensity of grassland management enhances bee diversity in a broad range of habitats. Moreover, wild bee communities are promoted by habitat types such as ruderal areas or woodland edges.
Journal of Soils and Sediments - Pesticide contamination of river waters is a global problem, and therefore, authorities regularly monitor the water quality status. Especially, flood events might... 相似文献
Landscape Ecology - Maintaining biodiversity in multifunction landscapes is a significant challenge. Planning for the impacts of change requires knowledge of how species respond to landscape... 相似文献
ABSTRACT The formation of phosphorus (P) compounds including iron-P, aluminum-P and calcium-P in highly weathered tropical soils can be altered upon biochar addition. We investigated the effect of corn cob biochar (CC) and rice husk biochar (RH) pyrolyzed at three temperatures (300°C, 450°C and 650°C) on phosphorus (P) fractions of three contrasting soils. A 90d incubation study was conducted by mixing biochar with soil at a rate of 1% w/w and at 70% field capacity. Sequential P fraction was performed on biochar, soil and soil-biochar mixtures. Increase in most labile P (resin-Pi, NaHCO3-Pi) and organic P fraction (NaHCO3-Po + NaOH-Po) in CC and RH biochars were inversely related to increasing temperature. HCl-Pi and residual P increased with increasing temperature. Interaction of CC and RH with soils resulted in an increase in most labile P as well as moderately labile P (NaOH-Pi) fractions in the soils. CC increased most labile P in the soils more than RH. The increase in most labile P fraction in soils was more significant at relatively lower temperatures (300°C and 450°C) than 650°C. However, the increase in HCl-Pi and residual P of the soils was more predominant at high temperature (650°C). The study suggested that biochar pyrolyzed at 300–450°C could be used to increase P bioavailability in tropical soils. 相似文献
Zusammenfassung Die Wirkung von 12 im Obstbau gebräuchlichen Fungiziden in praxisüblichen Anwendungskonzentrationen aufTrichogramma-Imagines wurde in Laborversuchen geprüft.Alle berücksichtigten Mehltau-Bekämpfungsmittel, Binapacryl, Dinocap, Triamphos und Chinomethionat, erwiesen sich als mehr oder weniger toxisch, desgleichen die Schorf-Bekämpfungsmittel Mancozeb, Dichlofluanid, Metiram und TMTD. Für die Schorf-Bekämpfungsmittel Captan, Dithianon, Dodin und Zineb wurde unter den Versuchsbedingungen keine Giftwirkung nachgewiesen.Die Angaben der Literatur über die Wirkung der genannten Fungizide aufTrichogramma und andere Chalcidoidea werden diskutiert.
Summary The effects uponTrichogramma adults of 12 fungicides which are commonly in use in orchards, in normal concentrations were examined by laboratory trials.The mildew fungicides, binapacryl, dinocap, triamphos, and oxythioquinox proved to be toxic as well as the apple scab fungicides mancozeb (= coordination product of zinc ion and [ethylenebis(dithiocarbamato)] manganese), dichlofluanid, metiram (= zinc-activated polyethylene thiuram disulfide), and thiram. Under the conditions of the experiments, there was no evidence of a toxic effect exerted by the apple scab fungicides captan, dithianon, dodine, and zineb.The available data from literature on the effects of the fungicides mentioned uponTrichogramma and other chalcidoids are discussed.
Durchgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.Dem Direktor des Instituts, Herrn Professor Dr. J. M. Franz, danke ich für sein reges Interesse an den Versuchen und die mir jederzeit gewährte Unterstützung. 相似文献
Twelve Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlots from coastal British Columbia were assayed for seedborne Fusarium. All of the seedlots were contaminated with Fusarium. Percent of nonstratified seeds from individual seedlots harboring Fusarium ranged from 0.3% to 95.4%. Sixty-seven percent of the seedlots had Fusarium on less than 2% of the seeds. Post-stratification seedborne Fusarium levels were significantly less for running water imbibition compared to standing water imbibition. However, seedling growth at a container nursery was not consistently different for stratified seed imbibed initially in standing or running water. Fusarium disease symptoms were not observed in the nursery environment. The species of Fusarium isolated from seed were F. acuminatum, F. avenaceum, F. lateritium, F. moniliforme, F. oxysporum, F. poae and F. sambucinum. Twelve Fusarium isolates, comprising six species, were assessed for pathogenicity. Disease symptoms were observed after four weeks incubation and Fusarium isolates ranged in virulence from low to high. Fusarium oxysporum isolates were the most pathogenic. 相似文献
The changes to the forest ownership structure of small private forests in recent times have opened up an intensive field of
research throughout Europe. Most of the studies completed to date adhere to the classic survey model and describe the behaviour
and attitudes of forest owners. The research presented in this article analyses the changes to small private forests with
the aid of data collected from focus groups comprised of forestry extension officers in Germany. Through the reconstruction
of the experiences gleaned by the consultants, it was possible to describe the manner in which they characterise their clientele,
and the changes they have observed, against the backdrop of changes occurring across rural areas. The consultants’ strategies
for describing forest owners are presented. The orientation pattern presented by the extension officers is compared with the
urban orientation of forest owners’ model developed by social scientists. 相似文献