苔藓植物资源保护利用中的生态环境效应研究进展

苔藓植物资源丰富、种类繁多、分布广泛,是一类以孢子繁殖,由水生向陆生过渡的高等植物。苔藓植物的结构相对简单,对环境变化的反应较为敏感,被广泛应用为环境污染的指示植物。苔藓植物生长与所处的环境有关,而它的生长对土壤结皮形成、水土保持、生态小环境改善等方面又发挥着重要的促进作用。综述了苔藓植物的资源分布、苔藓植物对环境污染的响应、苔藓植物的生态效应等方面的研究进展,但是目前的研究领域及其研究角度还存在着各自的不足。随着经济建设快速发展,世界各地大量的矿山开采、水电开发等工程建设对土地、自然环境的破坏日益严重,非农业建设以及农产品需求不断增加造成了农田的生态结构与功能发生着不断变化。针对各地经济社会发展以及城乡建设现状,积极开展工程建设领域以及农田生态系统苔藓植物的生态环境效应研究是今后值得十分重视的研究方向。     

苔藓植物资源保护利用中的生态环境效应研究进展

苔藓植物资源丰富、种类繁多、分布广泛,是一类以孢子繁殖,由水生向陆生过渡的高等植物。苔藓植物的结构相对简单,对环境变化的反应较为敏感,被广泛应用为环境污染的指示植物。苔藓植物生长与所处的环境有关,而它的生长对土壤结皮形成、水土保持、生态小环境改善等方面又发挥着重要的促进作用。综述了苔藓植物的资源分布、苔藓植物对环境污染的响应、苔藓植物的生态效应等方面的研究进展,但是目前的研究领域及其研究角度还存在着各自的不足。随着经济建设快速发展,世界各地大量的矿山开采、水电开发等工程建设对土地、自然环境的破坏日益严重,非农业建设以及农产品需求不断增加造成了农田的生态结构与功能发生着不断变化。针对各地经济社会发展以及城乡建设现状,积极开展工程建设领域以及农田生态系统苔藓植物的生态环境效应研究是今后值得十分重视的研究方向。     

Evaluating consistency of stakeholder input into participatory GIS-based multiple criteria evaluation: a case study of ecotourism development in Kurdistan

Multiple criteria evaluation (MCE) is often used with GIS to identify suitable sites for multi-purpose development such as ecotourism. Typically, expert or stakeholder consultation is used to identify weights reflecting the relative importance of map layers representing different criteria. The objective of this study was to evaluate a new consultative approach to GIS-based MCE, using ecotourism development in Kurdistan, Iraq, as a case study. In an initial and follow-up consultation, stakeholders were asked not only to assess the relative importance of different map layers for ecotourism development, but also to identify specific sites suitable for ecotourism. Seventy-eight ecotourism destinations nominated by participants had significantly higher MCE scores than a set of 58 locations chosen without reference to stakeholders (t-test = 21.16; p < 0.001). The approach thus provides a straightforward means of assessing the consistency of stakeholder input into MCE and could be adapted for use in other site suitability assessments.     

A review of current knowledge concerning dry deposition of atmospheric mercury

The status of the current knowledge concerning the dry deposition of atmospheric mercury, including elemental gaseous mercury (Hg⁰), reactive gaseous mercury (RGM), and particulate mercury (Hg_p), is reviewed. The air–surface exchange of Hg⁰ is commonly bi-directional, with daytime emission and nighttime deposition over non-vegetated surfaces and vegetated surfaces with small leaf area indices under low ambient Hg⁰ conditions. However, daytime deposition has also been observed, especially when the ambient Hg⁰ is high. Typical dry deposition velocities (V_d) for Hg⁰ are in the range of 0.1–0.4 cm s^?1 over vegetated surfaces and wetlands, but substantially smaller over non-vegetated surfaces and soils below canopies. Meteorological, biological, and soil conditions, as well as the ambient Hg⁰ concentrations all play important roles in the diurnal and seasonal variations of Hg⁰ air–surface exchange processes. Measurements of RGM deposition are limited and are known to have large uncertainties. Nevertheless, all of the measurements suggest that RGM can deposit very quickly onto any type of surface, with its V_d ranging from 0.5 to 6 cm s^?1. The very limited data for Hg_p suggest that its V_d values are in the range of 0.02–2 cm s^?1.A resistance approach is commonly used in mercury transport models to estimate V_d for RGM and Hg_p; however, there is a wide range of complexities in the dry deposition scheme of Hg⁰. Although resistance-approach based dry deposition schemes seem to be able to produce the typical V_d values for RGM and Hg⁰ over different surface types, more sophisticated air–surface exchange models have been developed to handle the bi-directional exchange processes. Both existing and newly developed dry deposition schemes need further evaluation using field measurements and intercomparisons within different modelling frameworks.     

The feeding behaviour of Schistocerca gregaria,the desert locust,on two starch mutants of Arabidopsis thaliana

Summary. Schistocerca gregaria, the desert locust, has been shown to regulate its dietary intake with respect to specific macronutrients in synthetic foods. This study examined the nutrients in the leaves of two starch mutants of Arabidopsis thaliana, and then compared the feeding behaviour of locusts on the two starch mutants. The high-starch mutant had c. 25 times more starch than the no-starch mutant. Newly molted 5th stadium locusts were preconditioned for 3 days on one of the mutants, and then observed for 90 min while exposed to the same or the alternative mutant. Locusts pretreated with the no-starch mutant fed longer during the first meal on high-starch mutants, spent more time feeding, and had the smaller latency to begin a meal when compared to the locusts pretreated on the high-starch mutant. The results of the study are interpreted in light of an integrative model of nutrient balancing. Received 16 November 1999; accepted 23 December 1999     

Modeling rural landowners' hunter access policies in East Texas,USA

Private landowners in East Texas, USA, were aggregated into one of four policy categories according to the degree of access allowed to their lands for hunting. Based on these categories, a logistic regression model of possible determinants of access policy was developed and probabilities of policy adoption were calculated. Overwhelmingly, attitudes toward hunting as a sport, incentives, and control over the actions of hunters were most predictive of landowners' policies. Additionally, the availability of deer was found to be negatively correlated with access, thereby suggesting management efforts to increase deer populations may be counter to increasing access. Further, probabilities derived from the model indicated that there was almost a 7 in 10 chance (0.66) that landowners would adopt policies commensurate with allowing family and personal acquaintances to hunt on their property. However, the probability of increasing access beyond this level, where access was provided for the general public, dropped off drastically to less than 5% (0.04).     

A case of paternal uniparental disomy for chromosome 11

We report a case of paternal uniparental disomy for chromosome 11 that presented as severe intrauterine growth retardation. Autopsy following intrauterine death also revealed aberrant intestinal rotation and hypospadias. Chromosome analysis of direct preparations from placental biopsy showed an abnormal 47,XY,+11 karyotype. Analysis of long-term cultures from the placenta revealed 46,XY/47,XY,+11 mosaicism. Fluorescence in situ hybridization (FISH) studies on interphase nuclei confirmed trisomy 11 in multiple placental sites but detected only disomic cells in fetal skin. Investigation using microsatellite polymorphisms demonstrated paternal isodisomy at loci D11S909, D11S956, and D11S488, and paternal heterodisomy at locus D11S928.     

Evaluation of sample recovery of malodorous livestock gases from air sampling bags, solid-phase microextraction fibers, Tenax TA sorbent tubes, and sampling canisters

Odorous gases associated with livestock operations are complex mixtures of hundreds if not thousands of compounds. Research is needed to know how best to sample and analyze these compounds. The main objective of this research was to compare recoveries of a standard gas mixture of 11 odorous compounds from the Carboxen/PDMS 75-microm solid-phase microextraction fibers, polyvinyl fluoride (PVF; Tedlar), fluorinated ethylene propylene copolymer (FEP; Teflon), foil, and polyethylene terephthalate (PET; Melinex) air sampling bags, sorbent 2,b-diphenylene-oxide polymer resin (Tenax TA) tubes, and standard 6-L Stabilizer sampling canisters after sample storage for 0.5, 24, and 120 (for sorbent tubes only) hrs at room temperature. The standard gas mixture consisted of 7 volatile fatty acids (VFAs) from acetic to hexanoic, and 4 semivolatile organic compounds including p-cresol, indole, 4-ethylphenol, and 2'-aminoacetophenone with concentrations ranging from 5.1 ppb for indole to 1270 ppb for acetic acid. On average, SPME had the highest mean recovery for all 11 gases of 106.2%, and 98.3% for 0.5- and 24-hr sample storage time, respectively. This was followed by the Tenax TA sorbent tubes (94.8% and 88.3%) for 24 and 120 hr, respectively; PET bags (71.7% and 47.2%), FEP bags (75.4% and 39.4%), commercial Tedlar bags (67.6% and 22.7%), in-house-made Tedlar bags (47.3% and 37.4%), foil bags (16.4% and 4.3%), and canisters (4.2% and 0.5%), for 0.5 and 24 hr, respectively. VFAs had higher recoveries than semivolatile organic compounds for all of the bags and canisters. New FEP bags and new foil bags had the lowest and the highest amounts of chemical impurities, respectively. New commercial Tedlar bags had measurable concentrations of N,N-dimethyl acetamide and phenol. Foil bags had measurable concentrations of acetic, propionic, butyric, valeric, and hexanoic acids.