基于水土流失敏感性的岩溶地区景观生态风险评价——以黔南州为例

为揭示岩溶地区水土流失与生态格局的相关性,分析水土流失敏感性背景下景观生态风险的空间特征。以黔南州为研究对象,融合RUSLE模型和ERI评价方法,在分析水土流失敏感性的基础上,对县域尺度的景观生态风险进行了定量化评价。结果表明:（1） 黔南州水土流失敏感性以中度、轻度和低敏感区为主,其总面积为22 974.42 km²,比重达88.86%,但重度、极度敏感区面积仅占11.14%,且降水侵蚀力、地表起伏度和石漠化等级的空间相关性高。（2） 低生态风险区主要由水土流失轻度、不敏感区构成,耕地面积比重大（72.07%）,高生态风险区则以中度、重度敏感区为主,且建设用地面积比重大,说明水土流失敏感性就越高,则区域生态风险越高。上述研究表明,从水土流失敏感性的角度评价景观生态风险,融合了景观格局和水土流失状况等信息,不仅丰富了区域生态风险评价方法,也为区域生态保护与修复提供了决策依据。     

毕节岩溶区坡耕地烟草镉安全评价研究

以贵州省毕节地区岩溶环境烟水配套工程为例,通过实地调查和采样,对烟草地土壤-烟草系统镉进行评价。结果表明,烟草地土壤镉含量0.12~0.67 mg.kg-1,平均0.40 mg.kg-1,已遭轻度-中度污染。水溶态、离子交换态、碳酸盐结合态、腐植酸态、铁锰氧化物结合态、强有机结合态和残渣态镉分别为0.024、0.100、0.033、0.067、0.096、0.019 mg.kg-1和0.016 mg.kg-1,其中离子交换态、铁锰结合态和腐植酸态占66%。全镉与水溶态、离子交换态和铁锰结合态,水溶态与离子交换态和碳酸盐结合态,离子交换态与铁锰氧化物结合态显著正相关,揭示了镉形态间的转化关系及其对烟草的潜在影响。烟株上部烟叶镉含量1.04～1.59 mg.kg-1,茎、根中镉残留量为0.2～1.4 mg.kg-1,可能与源自K326的主推和示范品种对镉的提取效率高有关。因此,建议采用吸收镉低的烟草品种和合理的差异性水肥管理措施,固定土壤中活性态镉,降低土壤镉向烟株的转移,以保障烟叶品质,同时妥善处理这些农业废弃物以保护环境。     

基于改进湍流模型和偏振成像技术的水下退化图像复原方法

为了满足工厂化水产养殖中过程控制的信息化要求,该文提出一种基于改进湍流模型结合偏振成像技术,具有较强鲁棒性的水下退化图像复原方法。考虑内外尺度对波结构函数影响,结合折射率谱,改进水下湍流退化模型以提高复原算法先验知识的完备性;基于改进的退化模型和水下前向散射光的偏振特性,利用偏振成像技术提取退化图像中的噪声特征;基于退化图像噪声特征,采用约束最小二乘滤波法进行退化图像复原;最后,对复原效果进行相应比较,结果表明在强湍流条件下本算法具有更为理想的复原效果。该研究可为复杂水流条件下水下退化图像复原方法研究提供参考。     

黄河三角洲盐碱地刺槐混交林对土壤脲酶活性的影响

以黄河三角洲盐碱地26年生刺槐＋臭椿混交林（RA）、刺槐＋白榆混交林（RU）和刺槐＋白蜡混交林（RF）为研究对象,以刺槐纯林（RP）和无林地（CK）为对照,研究刺槐混交林对土壤脲酶活性的影响。结果表明：1）同一林分中,土壤脲酶活性随土层深度的增加而减小;2）不同林分之间表现为刺槐混交林〉刺槐纯林〉无林地,RP、RU、RF、RA的脲酶活性分别是CK的4．02、4．74、5．08和5．01倍;3）在影响土壤脲酶活性的土壤因子方面,刺槐混交林较其纯林表现为降低了土壤密度、pH值和含盐量,增大了总孔隙度,增强了蓄水性能,增加了全氮、碱解氮和有机质的质量分数,增加了细菌和固氮菌的数量;4）总孔隙度、细菌、固氮菌、全N和有机质等土壤因子对刺槐混交林土壤脲酶活性的影响较大,建议用这些土壤因子作为评价刺槐混交林土壤脲酶活性的主要指标。     

Comparison of cavity modification and community involvement as strategies for hornbill conservation in Thailand

We monitored breeding success of hornbills in Thailand for four sympatric species at Khao Yai National Park during 1981-2002 and six species at Budo-Sungai Padi National Park during 1994-2002. Within a 60 km² study area at Khao Yai, the well protected area, use of available cavities ranged from 94% in 1984 to 50% in 1993. Competition for nesting cavities was 40% of cavities available indicating the shortage of suitable cavity. We monitored the cavity condition and modified 48 cavities and, between 1996 and 2000, these contributed annually 23-45% of nestings that were successfully fledged (n = 352). Within the 90 km² at Budo Mountain, with heavy human disturbance, use of available cavities for nesting decreased from 81% in 1997 to 30% by 2001 and of successful fledging from 96% in 1997 to 55% in 1999, but both increased once our involvement with local communities had eradicated poaching and reduced disturbance. Competition for nesting cavities here was 26% of cavities available indicating the effect of poaching. Both strategies were successful in the short term but long-term management of cavities in large forest trees is required at Khao Yai and of forest disturbance at Budo.     

贵州省岩溶地区坡度与土地石漠化空间相关分析

喀斯特石漠化从本质上来讲是喀斯特地区的成土速率远小于水土流失的速率而造成的土地生产力的退化过程.坡度起伏决定着地表现代侵蚀作用的强弱,影响着水土流失的强度;坡度越大,地表物质的不稳定性就越强,土壤越容易遭受侵蚀而变薄.在前期工作中,构筑了贵州省岩溶地区1∶500 000坡度分级图和石漠化分布图,对岩溶地区坡度图和石漠化图进行空间叠加分析,研究坡度与石漠化形成的相关关系.贵州省岩溶地区坡度主要集中于10°～25°之间,不同程度石漠化分布最集中的地区是＞25°的坡地区;在坡度＞18°的地区,石漠化的发生率基本随着坡度的增大而增大,强度石漠化的表现尤为明显;＜18°的坡地区石漠化程度主要以轻度和中度为主.     

基于GIS的喀斯特流域石漠化综合防治探讨——以贵州织金县洗马河流域为例

喀斯特石漠化是在喀斯特脆弱生态环境下,人类不合理的社会经济活动,造成植被破坏、水土流失、岩石逐渐裸露、土地生产力衰退丧失的演变过程,严重制约了区域社会经济的可持续发展。洗马河流域是织金洞国家级重点风景名胜区核心主成部分,主要岩性为灰岩和白云岩,喀斯特十分发育,是典型的石漠化区域,占流域面积近70%,人地矛盾十分突出。项目通过GIS与遥感技术为手段,进行石漠化调查和防治工程的布置,从而达到对该流域的石漠化防治,挽救该区域人类生存条件、防治水土流失、对国家重点风景名胜区的保护,同时对其它喀斯特区域石漠化的综合防治起着示范作用。     

Management strategies to increase stand structural diversity and enhance biodiversity in coastal rainforests of Alaska

Coastal rainforests of southeast Alaska have relatively simple species composition but complex structures with high diversity of tree ages, sizes and forest canopy layers, and an abundant understory plant community. Wildlife and fisheries resources also play an important role in the ecological functioning of forest and aquatic systems. Clearcutting has greatly altered these forest ecosystems with significant decreases in structural diversity of forest stands and greatly reduced wildlife habitat. This paper synthesizes information on management options in older forests that have never been actively managed, and in younger forests to increase diversity of stand structures and their associated effects on biodiversity. Light to moderate levels of partial cutting in old-growth forests can maintain the original diversity of overstory stand structures and understory plant communities. In younger forests that develop after clearcutting, mixed alder-conifer stands provide more heterogeneous structures and significantly higher understory biomass than in pure conifer forests. Research has shown that red alder increases diversity and abundance of understory plants, and provides forage for deer and small mammals. Results also show a clear linkage between alder and improved invertebrate diversity in aquatic systems. A combination of light partial cutting in older forests along with inclusion of red alder in conifer-dominated forests could provide the greatest amount of diversity and maintain the complex stand structures that are an important component of these forest ecosystems.     

贵州喀斯特山区石漠化生态环境背景与生态重建

贵州省地处中国西南喀斯特中心地区,是中国石漠化分布面积最大、危害最严重的省份。轻度以上的石漠化面积已达35 920 km2,占全省土地总面积的20.39%。由于贵州喀斯特石漠化生态环境背景的特殊性,其研究对石漠化的生态重建研究有着重要的意义。对此贵州省采取了一系列措施,但实施过程中尚存在一些问题。在总结前人的研究基础上,综合考虑贵州喀斯特石漠化生态地质环境背景的特殊性,提出适宜的生态重建措施。     

粤北岩溶山区农业水土环境问题及对策

粤北岩溶山区是广东省主要的贫困地区之一,自然环境先天脆弱,水土流失严重、水资源短缺、旱涝灾害频繁等一系列生态问题已成为制约当地社会经济可持续发展的关键因素。在广泛、深入调查的基础之上,分析了粤北岩溶山区农业水土环境问题的现状及主要成因,提出了改善农业生态环境,促进农业水土资源可持续发展的针对性措施。