The relationship between agricultural intensification and biological control: experimental tests across Europe

Agricultural intensification can affect biodiversity and related ecosystem services such as biological control, but large-scale experimental evidence is missing. We examined aphid pest populations in cereal fields under experimentally reduced densities of (1) ground-dwelling predators (-G), (2) vegetation-dwelling predators and parasitoids (-V), (3) a combination of (1) and (2) (-G-V), compared with open-fields (control), in contrasting landscapes with low vs. high levels of agricultural intensification (AI), and in five European regions. Aphid populations were 28%, 97%, and 199% higher in -G, -V, and -G-V treatments, respectively, compared to the open fields, indicating synergistic effects of both natural-enemy groups. Enhanced parasitoid: host and predator: prey ratios were related to reduced aphid population density and population growth. The relative importance of parasitoids and vegetation-dwelling predators greatly differed among European regions, and agricultural intensification affected biological control and aphid density only in some regions. This shows a changing role of species group identity in diverse enemy communities and a need to consider region-specific landscape management.     

CHANGES IN LAND USE/MANAGEMENT AND WATER QUALITY IN THE LONG CREEK WATERSHED1

ABSTRACT: Surface water in the Long Creek watershed, located in western Piedmont region of North Carolina, was monitored from 1993 to 2001. The 8,190 ha watershed has undergone considerable land use and management changes during this period. Land use surveys have documented a 60 percent decrease in cropland area and a more than 200 percent increase in areas being developed into new homes. In addition, more than 200 conservation practices have been applied to the cropland and other agricultural land that remains in production. The water quality of Long Creek was monitored by collecting grab samples at four sites along Long Creek and continuously monitoring discharge at one site. The monitoring has documented a 70 percent reduction in median total phosphorus (TP) concentrations, with little reductions in nitrate and total Kjel‐dahl nitrogen, or suspended sediment levels. Fecal coliform (FC) and streptococci (FS) levels declined significantly downstream as compared to upstream during the last four years of monitoring. This decrease was attributed to the implementation of waste management practices and livestock exclusion fencing on three dairy operations in the watershed. Annual rainfall and discharge increased steadily until peaking in the third year of the monitoring period and varied while generally decreasing during the last four years of the project. An array of observation, pollutant concentration, and hydrologic data provide considerable evidence to suggest that the implementation of BMPs in the watershed have significantly reduced phosphorus and bacteria levels in Long Creek.     

The effect of patch isolation on epifaunal colonization in two different seagrass ecosystems

The macrofaunal colonization of isolated habitats is affected by many factors, ranging from distance to the nearest source population to the dispersal mechanism of the species. We investigated the initial epifaunal colonization at two sites, one situated in the Northern Gulf of Mexico and the other in the Northern Baltic Sea. At each site, artificial seagrass units were placed at 10- and 20-m distances from a continuous seagrass meadow, as well as inside the meadow over a 5-day colonization time. With the exception of amphipods in Gulf of Mexico, patch isolation had a negative effect on colonization for the other faunal species, irrespective of the sites. This inverse colonization pattern of amphipods suggests that they are not equally sensitive to patch isolation in different regions. Our results indicate that increasing habitat isolation can have serious consequences for the community composition of seagrass epifauna. Furthermore, we emphasize the need for larger-scale latitudinal comparative studies.     

Ethnobotany and Management of Dimorphandra gardneriana in a Protected Area of Chapada do Araripe Semiarid Ceará, Northeastern Brazil

The development of conservation strategies for nontimber forest products requires the characterization of the management systems and ethnoecological knowledge of the used species, as well as the analysis of the biological impacts of these processes. This study aimed to evaluate management systems and extractivist areas and related ethnoecological knowledge of Dimorphandra gardneriana (fava d’anta) in the semiarid region of Ceará, Northeast of Brazil. Fava d’anta produces fruits with high concentration of bioflavonoids, substances with various pharmacological properties, being exploited by extractivist communities in the mosaic of protected areas in Chapada do Araripe, Ceará. Ethnoecological knowledge has been concentrated on collectors who have been in activity for a longer time and/or plant the species. We identified three management systems that can impact in different ways on fava d’anta populations, depending on the area and level of human interference with the species. The extractivists respect the zoning of protected areas and do not enter in the full protection area, choosing areas with the highest tree density. The different systems produce a mosaic that creates different extraction opportunities and modifications to the local landscape and to fava d’anta populations. Factors that may have effects on the conservation of the species are the lack of supervision and overexploitation of the resource in native areas, while the factors that affect the health of extractivists are the infrastructure of the work and exposure to wild environments.     

Measuring Urban Water Conservation Policies: Toward a Comprehensive Index

This article (1) discusses existing efforts to measure water conservation policies (WCPs) in the United States (U.S.); (2) suggests general methodological guidelines for creating robust water conservation indices (WCIs); (3) presents a comprehensive template for coding WCPs; (4) introduces a summary index, the Vanderbilt Water Conservation Index (VWCI), which is derived from 79 WCP observations for 197 cities for the year 2015; and (5) compares the VWCI to WCP data extracted from the 2010 American Water Works Association (AWWA) Water and Wastewater Rates survey. Existing approaches to measuring urban WCPs in U.S. cities are limited because they consider only a portion of WCPs or they are restricted geographically. The VWCI consists of a more comprehensive set of 79 observations classified as residential, commercial/industrial, billing structure, drought plan, or general. Our comparison of the VWCI and AWWA survey responses indicate reasonable agreement (ρ = 0.76) between the two WCIs for 98 cities where the data overlap. The correlation suggests the AWWA survey responses can provide fairly robust longitudinal WCP information, but we argue the measurement of WCPs is still in its infancy, and our approach suggests strategies for improving existing methods.     

Heat stress and crop yields in the Mediterranean basin: impact on expected insurance payouts

Insurance programmes have been indicated as a tool to reduce the economic risk associated with climate change, and crop growth simulation models can be used effectively to assess future trends in crop insurance payouts. This paper assesses the economic role of increasing weather extremes under future climate change on the expected insurance payouts for durum wheat (Triticum turgidum L. spp. durum) over the Mediterranean basin, focusing attention on the effects of heat stresses (HSs). A crop growth simulation, Sirius Quality version 2 (SQ2), calibrated for three varieties (long, medium and short growth cycle) was applied on seven sites under present (1975–1990) and future climate conditions (2030–2050) obtained from five regional circulation models under SRES scenario A1b. The intensity of HSs at anthesis was included as reducing factor of yield originally simulated by SQ2 calculated according to a specific empirical model. Simulated yields were then fitted to the most appropriate distribution, which was used to calculate the expected payouts according to the probability of yields being below a guaranteed level. We found that the simulated crop yields were, in general, negatively skewed and that Weibull probability density function (PDF), admitting negative skewing, provided the best performances in their fitting. The simulation of HSs modified the original shape of the Weibull PDF by increasing the skewness of the distribution. The results of the insurance model indicated that the modification of crop PDFs induced by HSs led to a general increase in payouts with respect to unstressed conditions, with a marked difference between present (+11 %, on average for the selected sites) and future periods (+25 %). When compared to the present, a general decrease in payouts (?1.1 %) was observed when HSs were not included in the simulations. Conversely, HSs impact resulted in a general increase in payouts (+10.3 %) where the highest increase was detected for the long growth cycle variety (+16.6 %) and the lowest for that with short growth cycle (?1.6 %). These results emphasize the importance of the appropriate characterization of crop yield distribution, the economic implications of HSs in a risk management context and a possible strategy to cope with climate change and variability.     

Comparison of GC and LC determinations of hexabromocyclododecane in biological samples - results from two interlaboratory comparison studies

In order to assess the quality and comparability of results from determinations of 1,2,5,6,9,10-hexabromocyclododecane (HBCD) in biological samples, two interlaboratory comparison studies have been organized. Up to 13 laboratories determined either the total HBCD concentration, or concentrations of alpha-, beta- and gamma-HBCD, or both in cod liver oil, herring filet, salmon filet, butter and chicken meat. The laboratories were able to determine total HBCD concentrations in the marine samples with satisfying quality (RSD <35%). However, the analysis of samples with low HBCD contamination (相似文献   

Population exposure and mortality due to regional background PM in Europe – Long-term simulations of source region and shipping contributions

This paper presents the contribution to population exposure (PE) of regional background fine primary (PPM_2.5) and secondary inorganic (SIA) particulate matter and its impact on mortality in Europe during 1997–2003 calculated with a chemistry transport model. Contributions to concentrations and PE due to emissions from shipping, Western (WEU), Eastern (EEU), and Northern Europe are compared.WEU contributes about 40% to both PPM_2.5 and SIA concentrations, whereas the EEU contribution to PPM_2.5 is much higher (43% of total PPM_2.5) than to SIA (29% of total SIA). The population weighted average concentration (PWC) of PPM_2.5 is a factor of 2.3 higher than average (non-weighted) concentrations, whereas for SIA the PWC is only a factor 1.6 higher. This is due to PPM_2.5 concentrations having larger gradients and being relatively high over densely populated areas, whereas SIA is formed outside populated areas. WEU emissions contribute relatively more than EEU to PWC and mortality due to both PPM_2.5 and SIA in Europe.The number of premature deaths in Europe is estimated to 301 000 per year due to PPM_2.5 exposure and 245 000 due to SIA, despite 3.3 times higher average SIA concentrations. This is due to population weighting and assumed (and uncertain) higher relative risk of mortality for PPM_2.5 components (2.8 times higher RR for PPM_2.5). This study indicates that it might be more efficient, for the health of the European population, to decrease primary PM emissions (especially in WEU) than to decrease precursors of SIA, but more knowledge on the toxicity of different PM constituents is needed before firm conclusions can be drawn.