Landscape services: the concept and its practical relevance   总被引：1，自引：1，他引：0  

Olaf Bastian  Karsten Grunewald  Ralf-Uwe Syrbe  Ulrich Walz  Wolfgang Wende 《Landscape Ecology》2014,29(9):1463-1479

Recently, in addition to the popular concept of “ecosystem services” (ES), the term “landscape services” (LS) has come into use. We are examining the question of whether a stronger focus on LS would be useful, particularly with regard to case studies carried out in Germany. Important reasons for introducing the term LS include the prominent role of spatial aspects, the reference to landscape elements and the landscape character, and the relevance of LS for landscape planning. We found no strong arguments for replacing the concept of ES by LS; however, we do prefer a situation-related use of both concepts. We propose the following definition: Landscape services are the contributions of landscapes and landscape elements to human well-being.  相似文献   

Distribution and establishment of the alien Australian redclaw crayfish,Cherax quadricarinatus,in the Zambezi Basin     

Takudzwa C. Madzivanzira  Josie South  Bruce R. Ellender  Russell Chalmers  Gethings Chisule  Christine R. Coppinger  Fernandu H. Khaebeb  Francois J. Jacobs  Machaya Chomba  Bumango Musando  Chanda Mwale  Tamuka Nhiwatiwa  Craig L. Rennie  Naomi Richardson  Olaf L. F. Weyl 《水产资源保护:海洋与淡水生态系统》2021,31(11):3156-3168

1. Crayfish are invasive polytrophic keystone species, which are phylogenetically unique on the African continent. The Australian redclaw crayfish Cherax quadricarinatus is invasive in southern African freshwater systems including the Zambezi River Basin. Surveys conducted across the Zambezi Basin (Botswana, Zimbabwe, Namibia and Zambia) between 2017 and 2019 showed that C. quadricarinatus is broadly distributed across the Upper and Middle Zambezi and is rapidly spreading through natural and human-mediated means across several ecoregions.
2. The probability of capture (P_capture), catch per unit effort (CPUE) and population characteristics of C. quadricarinatus from the recent Barotse floodplain invasion were compared with older invasions from Lake Kariba and Kafue River.
3. The P_capture and CPUE of C. quadricarinatus in the recently invaded region of the Barotse floodplain were similar to those of the older invasions. Mass and carapace length of C. quadricarinatus from the Barotse floodplain were significantly lower than those of C. quadricarinatus from the older invasions. Sex ratios differed significantly between the three invasive populations. The Barotse floodplain population had a disproportionate investment in females (65.3%) and intersex individuals (8.4%). No crayfish were detected in the Zambezian Headwaters or the Okavango Floodplains ecoregions, but current spread rates are 49 km yr⁻¹ downstream and 12 km yr⁻¹ upstream.
4. Investment in population management and the prevention of spread will have high conservation value across the invaded regions in order to restrict crayfish ecological impacts via direct predation and competition. In areas where crayfish are in high abundance, existing fisheries are affected through damage to nets, leading to increased net abandonment and ghost gear pollution in invaded regions.
5. The emphasis should be on developing cohesive transboundary biosecurity policies in southern Africa to limit further spread that will threaten the integrity of freshwater ecosystems. However, long-term monitoring is needed to gauge invasion risk to sensitive areas such as the Okavango Floodplains ecoregion and determine field-based ecological impacts.

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Development of a radioimmunoassay for the quantitative determination of 8-prenylnaringenin in biological matrices     

Schaefer O  Bohlmann R  Schleuning WD  Schulze-Forster K  Hümpel M 《Journal of agricultural and food chemistry》2005,53(8):2881-2889

Seven carboxylic acid haptens of 8-prenylnaringenin (8-PN) were synthesized, coupled to cationized bovine serum albumin, and employed to raise specific antisera in rabbits. Two linkers of different lengths (C3H6COOH and C6H12COOH) were coupled to the C7-OH group and separated into their respective enantiomers yielding the first four haptens. Racemic derivatives with C4'-OH coupled linkers C5H10COOH and C9H18COOH were synthesized carrying a methylated C7-OH. Another racemic C4'-OH hapten (CH2COOH) was prepared starting from naringenin. The haptens elicited variable antibody titers dependent on linker lengths, with short linkers giving the best results. Three antisera were characterized in detail: anti-C7-carboxy-propyloxy-2S-(-)-8-PN (anti-H-11), anti-C7-carboxy-propyloxy-2R-(+)-8-PN (anti-H-10), and anti-C4'-carboxy-methoxy-rac-8-PN (anti-H-25). anti-H-10 and anti-H-11 showed about 9% enantiomeric cross-reactivity, and anti-H-11 did not discriminate between isoxanthohumol (IX) and 8-PN (84% cross-reactivity). For anti-H-10, cross-reactivities in the range of 2-5% were found for xanthohumol, IX, and 6-prenylnaringenin. Respective numbers for anti-H-25 were 0.02, 0.1, and 0.2%. Tritiated 8-PN was synthesized yielding a 3H-tracer of high specific radioactivity (2.22 GBq/mg). A radioimmunoassay using anti-H-25 and 3H-8-PN was established and used for the quantitative determination of 8-PN in various beer brands and in the urine of six men after the consumption of three different brands of beer. Furthermore, the dose-dependent excretion of 8-PN was tested after the consumption of a higher volume of a single beer brand with and without spiking with 8-PN and a small oral dose of authentic 8-PN, respectively. Conflicting results led to a pilot test on the in vivo conversion (demethylation) of IX into 8-PN in two men. Conversion rates of 1.9 and 4.4% were estimated. Thus, the total 8-PN dose in beer brands spiced with natural hop or hop products seems to be the sum of the 8-PN amount in a consumed volume and the amount arising from the conversion of IX.  相似文献   

Investigation of the occurrence of Angiostrongylus vasorum in coyotes in southern Ontario,Canada     

Jonathon D. Kotwa  Manuela Schnyder  Claire M. Jardine  Peter Deplazes  David L. Pearl  Olaf Berke  Nicola Mercer  Andrew S. Peregrine 《Journal of veterinary diagnostic investigation》2021,33(4):664

In North America, the only endemic focus for Angiostrongylus vasorum (French heartworm) was historically thought to occur in the southeastern part of the island of Newfoundland. However, reports of A. vasorum infection in wild canids in West Virginia, USA, and Nova Scotia, Canada, suggest the introduction of the parasite to mainland North America. We screened for A. vasorum in coyotes from across southern Ontario. Additionally, we evaluated the performance of ELISAs for detection of circulating A. vasorum antigen (Ag-ELISA) and antibodies against A. vasorum (Ab-ELISA) designed for use in sera or blood of foxes for use with coyotes in this region. Autopsies were performed on 397 coyotes, and lung tissue extract prepared from each carcass was tested via both ELISAs. The sensitivity and specificity for both tests were estimated in the absence of a gold standard using a 2-test single population Bayesian model; sensitivity and specificity priors were based on the performance of the assays in foxes in Switzerland. Eight coyotes tested positive for A. vasorum antigen; no animal was antibody positive. The estimated sensitivity and specificity of the Ag-ELISA were 90.8% (95% credible interval [CrI]: 83.8–95.6%) and 95.5% (95% CrI: 93.4–97.2%), respectively. For the Ab-ELISA, the estimated sensitivity and specificity were 41.9% (95% CrI: 32.1–51.9%) and 98.0% (95% CrI: 96.3–99.0%), respectively. Based on these findings and negative postmortem data for the same animals, there is insufficient evidence to suggest the presence of A. vasorum in southern Ontario coyotes.  相似文献   

Modeling the timber supply impact of introducing weevil-resistant spruce in British Columbia with cellular automata     

Olaf Schwab  Thomas Maness  Gary Bull  Clive Welham  Brad Seely  Juan Blanco 《Forest Policy and Economics》2011,13(1):61-68

Assessing the impacts of cumulative, non-lethal damages to forests poses a particular challenge to forest management planning since cumulative merchantable volume losses are not known until the time of harvest. This paper introduces a model that scales stand-level processes to their large-scale implications by combining elements of growth and yield modeling, insect infestation modeling, and large-scale spatial harvest simulation. The model is described and tested using the proposed large-scale introduction of weevil-resistant spruce in British Columbia, Canada as a case study. While spruce weevil damages were found to be significant, only a relatively small percentage of losses can be avoided by planting resistant stock. The model introduced in this paper can serve as an important decision support tool for policy makers and researchers in assessing the large-scale effects of proposed policy and management interventions.  相似文献   

Inhibition of hepatitis B virus replication by drug-induced depletion of nucleocapsids     

Deres K  Schröder CH  Paessens A  Goldmann S  Hacker HJ  Weber O  Krämer T  Niewöhner U  Pleiss U  Stoltefuss J  Graef E  Koletzki D  Masantschek RN  Reimann A  Jaeger R  Gross R  Beckermann B  Schlemmer KH  Haebich D  Rübsamen-Waigmann H 《Science (New York, N.Y.)》2003,299(5608):893-896

Chronic hepatitis B virus (HBV) infection is a major cause of liver disease. Only interferon-alpha and the nucleosidic inhibitors of the viral polymerase, 3TC and adefovir, are approved for therapy. However, these therapies are limited by the side effects of interferon and the substantial resistance of the virus to nucleosidic inhibitors. Potent new antiviral compounds suitable for monotherapy or combination therapy are highly desired. We describe non-nucleosidic inhibitors of HBV nucleocapsid maturation that possess in vitro and in vivo antiviral activity. These inhibitors have potential for future therapeutic regimens to combat chronic HBV infection.  相似文献   

Rapid formation of sulfuric acid particles at near-atmospheric conditions   总被引：1，自引：0，他引：1  

Berndt T  Böge O  Stratmann F  Heintzenberg J  Kulmala M 《Science (New York, N.Y.)》2005,307(5710):698-700

We investigated the formation of new particles in a laboratory study, starting from H2SO4 produced in situ through the reaction of OH radicals with SO2. Newly formed particles were observed for H2SO4 concentrations above 7 x 10(6) per cubic centimeter. At 293 kelvin, a rough estimate yielded a nucleation rate of 0.3 to 0.4 particles per cubic centimeter per second for approximately 10(7) particles per cubic centimeter of H2SO4 (particle size >/= 3 nanometers). These findings are in agreement with observations from the atmosphere. The results demonstrate that under laboratory conditions similar to the atmosphere, particle formation occurs at atmospheric H2SO4 concentration levels.  相似文献   

A PINOID-dependent binary switch in apical-basal PIN polar targeting directs auxin efflux   总被引：1，自引：0，他引：1  

Friml J  Yang X  Michniewicz M  Weijers D  Quint A  Tietz O  Benjamins R  Ouwerkerk PB  Ljung K  Sandberg G  Hooykaas PJ  Palme K  Offringa R 《Science (New York, N.Y.)》2004,306(5697):862-865

Polar transport-dependent local accumulation of auxin provides positional cues for multiple plant patterning processes. This directional auxin flow depends on the polar subcellular localization of the PIN auxin efflux regulators. Overexpression of the PINOID protein kinase induces a basal-to-apical shift in PIN localization, resulting in the loss of auxin gradients and strong defects in embryo and seedling roots. Conversely, pid loss of function induces an apical-to-basal shift in PIN1 polar targeting at the inflorescence apex, accompanied by defective organogenesis. Our results show that a PINOID-dependent binary switch controls PIN polarity and mediates changes in auxin flow to create local gradients for patterning processes.  相似文献   

Zero tillage impacts in India's rice–wheat systems: A review     

Olaf Erenstein  Vijay Laxmi 《Soil & Tillage Research》2008,100(1-2):1-14

To date, the most widely adopted resource conserving technology in the Indo-Gangetic Plains (IGP) of South Asia has been zero-tillage (ZT) wheat after rice, particularly in India. The paper reviews and synthesizes the experience with ZT in the Indian IGP. ZT wheat is particularly appropriate for rice–wheat systems in the IGP by alleviating system constraints by allowing earlier wheat planting, helping control the weed Phalaris minor, reducing production costs and saving water. ZT wheat after rice generates substantial benefits at the farm level (US$97 ha⁻¹) through the combination of a ‘yield effect’ (a 5–7% yield increase, particularly due to more timely planting of wheat) and a ‘cost savings effect’ (US$52 ha⁻¹, particularly tillage savings). These benefits explain the widespread interest of farmers and the rapidity of the diffusion across the Indian IGP, further aided by the wide applicability of this mechanical innovation.  相似文献