河北省海岸带土地利用空间格局

海岸带由于其特殊的地理区位,土地利用方式和结构迥异于内陆地区。为揭示河北省海岸带土地利用空间格局,以海岸线向陆地延伸10 km作为研究范围,通过土地利用相对优势度和综合利用程度两种方法分析了河北省海岸带土地利用结构现状、空间格局和集约化特征。结果表明:河北省海岸带土地利用的主要类型为水库/坑塘、旱地和建筑用地;水库/坑塘、河流/湖泊和建筑用地、未利用地向海特征显著,是海岸带的优势土地利用类型;海岸带土地利用的海陆梯度和高程分异特征明显,主要表现为主要土地利用类型由水库/坑塘和建筑用地向旱地和林地转变;集约化利用程度最高的区域在距海岸线0～6 km、高程10～50 m的空间范围内。在沿海开发热潮再次兴起的背景下,关注海岸带土地利用空间格局现状,对优化海岸带国土空间开发格局具有重要意义。     

滨海水稻土腐殖质的组成及随种稻时间演变的研究初报

通过研究滨海水稻土腐殖质各成分的组成及性质,结果表明各组分有机碳及氮含量均为表层最高,C/N在结构相对稳定的结合态腐殖质和胡敏酸(HA)中波动较小,而在游离态腐殖质和富里酸(FA)中变化较大。随着种稻时间变长,结合态的腐殖质和胡敏酸有在土壤中积累的趋势,在1 000 a水稻土中腐殖质的芳香化程度最高、结构最复杂。     

滨海生态系统废弃物资源综合利用的生态恢复工程

在滨海淤泥质滩涂生态系统中采取以植物绿化为主的生态恢复工程，由于缺少土壤改造的适宜的资源，常成为工程正常实施的主要困难．通常情况下采用的从周边地区购买农田种植土的方法，不仅破坏采土区的生态环境，而且造价高．天津经济开发区通过对其周边环境中大量存在的海湾泥、碱渣和粉煤灰等固体废弃物资源的研究发现，当它们单独存在时，都不是　合适的土壤资源，但当以适当比例配合后，其混合物却更适合植物的生长．用它作为土壤资　源，将不仅能解决大量固体废弃物对滨海生态系统的污染问题，而且还可以减少对周边地区　生态环境的破坏，降低生产成本．海湾泥与碱渣和粉煤灰的最佳推荐比例为３∶１．     

Coastal dynamics and impact of coastal protection works on the Spurn Head spit (UK)

The erosion of the glacial tills along the Holderness Coast (eastern England) has released material which has led to the formation of a 4.5 km sand and gravel spit, Spurn Head, across the mouth of the Humber estuary. This paper examines the sedimentology and geomorphology of the spit and of the tidal flat behind it (Spurn Bight), and assesses the effects of coastal defences on the nearshore dynamics. A study of the coastal dynamics was carried out by analysing wind data and modelling wave shoaling and refraction at the estuary mouth, and on the tidal flat. The geomorphology and sedimentology of the beaches and the tidal flat were studied to assess the response of the spit system to different weather conditions.The results show that only 6% of the longshore drift produced by cliff erosion in Holderness is transported along Spurn Head, mainly by waves from the north and the north-east. This drift is stored in an area of sand and gravel banks at the tip. Medium-size sand is carried around the tip by south-easterly waves, leading to the formation of a small area of tidal sand waves. Waves from the southwest, which originate within the estuary, spread the sand over the tidal flat, but are not able to carry it towards the most northern inner part of the spit. Coastal defences built along the spit have slowed its rate of landward migration and prevented overwash processes. The defences have not been maintained for the last 30 years so that the spit is now likely to be breached in the winter months whenever surge conditions exist.     

Scuba diver behaviour and the management of diving impacts on coral reefs

Coral reefs worldwide are attracting increasing numbers of scuba divers, leading to growing concern about damage. There is now a need to manage diver behaviour closely, especially as many dive companies offer unlimited, unsupervised day and night diving from shore. We observed 353 divers in St. Lucia and noted all their contacts with the reef during entire dives to quantify rates of damage and seek ways of reducing it. Divers using a camera caused significantly more contacts with the reef than did those without cameras (mean 0.4 versus 0.1 contacts min⁻¹), as did shore versus boat dives (mean 0.5 versus 0.2 contacts min⁻¹) and night versus day dives (mean 1.0 versus 0.4 contacts min⁻¹). We tested the effect of a one-sentence inclusion in a regular dive briefing given by local staff that asked divers to avoid touching the reef. We also examined the effect of dive leader intervention on rates of diver contact with the reef. Briefing alone had no effect on diver contact rates, or on the probability of a diver breaking living substrate. However, dive leader intervention when a diver was seen to touch the reef reduced mean contact rates from 0.3 to 0.1 contacts min⁻¹ for both shore and boat dives, and from 0.2 to 0.1 contacts min⁻¹ for boat dives. Given that briefings alone are insufficient to reduce diver damage, we suggest that divers need close supervision, and that dive leaders must manage diver behaviour in situ.     

Revisiting the relationship between common weather variables and loblolly–shortleaf pine seed crops in natural stands

Seed production was monitored during24 years using seed-collection traps inloblolly–shortleaf pine (Pinus taeda L.–P.echinata Mill.) stands located in southeast Arkansas,north-central Louisiana, and southwest Mississippi onthe southeastern Coastal Plain, USA. Sound seedproduction was correlated with mean monthlyprecipitation and temperature from National Oceanicand Atmospheric Administration weather stationslocated near the seed-collection areas to determinethe potential of weather factors in forecasting pineseed crops. Correlations were restricted to threecritical periods in the pine reproductive cycle –strobili primordia differentiation, pollination, andfertilization. The most important (P 0.05)variables correlated with pine seed production for combined locations were cumulative precipitation (r = +0.60) during July, August, and September at 27 to 25 months before seed dispersal and mean temperature (r = –0.45) in August at 26 months before seed dispersal. Because multiple environmental factors can negatively impact pine seed development during the two yearsfollowing strobili primordia differentiation,seed-production forecasts based on weather variablesshould be verified by on-site cone counts during thesummer preceding autumn seed dispersal.     

江苏海岸带林农复合模式林分密度研究

对江苏海岸带１－４年生５种造林密度林农复合模式的综合经济效益进行了较系统地调查和评价。结果表明：在造林后１￣２ａ内,林分密度对林农复合经营影响不明显,２ａ后,则成为制约林农复合经营综合经济效益的主导因子,在５种密度林农复合模式中以农林比例５：１,株行距采用小株距、大行距配置形式的综合经济效益最高;会议收益率为１９．６５％,净现值为５８２５．５７元／ｈｍ＾２,净现值指数为１．７１２,林业农业土地经济     

Land classification for choice of tree species on farm lands in the Attock District of Punjab,Pakistan

In Pakistan, particularly in Punjab Province, it is difficult for agrofarmers to combine their indigenous knowledge and modern scientific methods to evaluate existing traditional farming systems and forestry practices. This requires an evaluation of indigenous soil classification in simple terms along with knowledge of the local flora, especially trees. This study focuses on land suitability classification for trees in the Attock District of Punjab, Pakistan. A survey was conducted which included interviews of local agrofarmers as well as standard soil analyses including both chemical and physical determinations of local soil types. An evalu- ation of soil types for cultivation of various crops was carried out given its total extent, component soil series and their proportions, spotting characteristics of each soil series and their major limitations/hazards for trees/crops. These would lead to the identification of various tree species according to soil characteristics. Then, according to the soil types and species, a land suitability map was obtained for the choice of tree species by using geographic information system (GIS) software. Land suitability classification will help local agroforesters/agrofarmers in matching suitable agricultural trees/crops properly for different soils in the area.     

辽宁省海岸带木本植物科的地理成分分析

应用辽宁省森林资源二类调查数据、辽宁省海岸带遥感卫星数据,结合实地补充调查数据进行统计,确定辽宁省海岸带1km宽范围内共有种子植物76科190属316种,其中木本植物40科75属127种。隶属于中国种子植物15个分布区类型中的7个,占46.67%,占辽宁省树木志报道的木本植物68科的58.8%。统计分析表明,辽宁省海岸带木本植物除少数属世界分布科之外,热带和温带的科数分别占40%和37.5%,说明植物区系属热带性质与温带性质。可以为海岸带特殊的地理环境下引进木本植物、栽植乡土树种和合理配置树种提供科学依据。     

Secondary Nothofagus dombeyi forests: site index curves and dominant height in the Coastal Range of south-central Chile

Nothofagus dombeyi is distributed on very diverse sites in the temperate forests of Chile and Argentina. In Chile, studies on its dynamics and productivity in forests, where it is the dominant species, have been carried out mainly in the foothills of the Andes, but the productivity and growth of these forests in the Coastal Range are almost unknown. The objective of this study was to evaluate the construction of a single dominant height/age growth model for two homogeneous edaphoclimatic zones (ZEH 2 and 5) previously defined for this species in the Coastal Range of south­central Chile. The results showed that the Chapman-Richards model was the best candidate function, in terms of goodness of fit and predictive capabilities. Using this function, specific parameters (a, b and c) were obtained for each zone, from which site models were constructed by the Algebraic Difference Approach method for a base age of 35 years. This model is intended to contribute to better estimations of site productivity for N. dombeyi forests in the Coastal Range of south-central Chile, and thus facilitate private and public decisions regarding their management.