鄱阳湖湿地生态系统退化的社会经济根源研究

鄱阳湖湿地生态系统是一个复杂、开放的交互系统。近些年,鄱阳湖湿地生态系统退化有加剧的趋势,其中有自然的原因,但更重要的是在社会经济发展过程中引起自然环境的破坏和生态规律的波动。人口持续增长、不合理的经济发展模式、湿地保护相关政策的缺失等都加剧了湿地生态系统的退化。加强湿地管理与保护、调整区域经济发展方式、构建环鄱阳湖生态经济区等措施,对保护和开发鄱阳湖湿地有重要的作用。     

Effects of Introduced Salmonids on a Montane Population of Iberian Frogs

Abstract:  Amphibians are declining worldwide because of multiple factors, including human-mediated introduction of fishes into naturally fishless areas. Although several studies have focused on the effect of exotic fishes on native amphibians breeding in ponds or lakes, little is known about their effects on stream-breeding species. We studied the effects of introductions of native brown trout ( Salmo trutta ) and exotic brook trout ( Salvelinus fontinalis ) on the stream-breeding, endemic Iberian frog (  Rana iberica ) in a protected area in central Spain. We assessed occurrence patterns of tadpoles and salmonids and compared habitat use of the three species. We also determined experimentally whether chemical cues from salmonids elicited antipredator behavior in tadpoles. Finally, we assessed the relative influence of tadpole habitat preferences, differences in salmonid species, and invasion geography on tadpole occurrence. Despite widely overlapping habitat preferences, tadpoles and trout did not coexist, with the former restricted to fishless habitats. Tadpoles detected chemical cues from both trout species and reacted by decreasing their activity, although the response toward the native brown trout was stronger. The residual distribution of Iberian frogs in Peñalara is better explained by the geography of fish invasions than by the fish species involved. Measures such as fish extirpation from certain areas, aimed at recovering lost habitat and improving connectivity among remaining populations of Iberian frogs, seem critical for the species' long-term survival in central Spain.     

Implications of mangrove dynamics for private and use in bragança, north Brazil: a case study

This work analyses effects of recent variations in the tidal inundation frequency in a mangrove ecosystem in the Bragança peninsula, North Brazil, and its implications for land occupation and use. Field data, time series of remote sensing images and local legislation were analysed focusing on the potential socio-economic impact of a changing environmental setting due to a rise in relative sea level. In the investigated period (1972–1997), vegetation changes along the coastline indicate net losses of mangrove coverage. In the central part of the peninsula, a topographically higher herbaceous plain constituting part of a farm presents an active progression of mangrove forest into an area previously dominated by grasses and herbs. This area measured 8.8 km² in 1972 but was gradually reduced to 5.6 km² in 1997, while progressively replaced by a monospecific stand of the black mangrove,Avicennia germinans. A linear extrapolation indicates that the elevated plain may be completely covered by mangrove by 2035. Current Brazilian legislation prohibits the extraction of mangrove trees without an officially approved management plan. Thus, the usable area of the farm has suffered a reduction by ca. 36% over 25 yr and we predict that is could be entirely replaced by mangroves in the next 35 yr. In this case study, legislation and ecosystem characteristics are analysed and a management plan discussed which could represent income alternatives for affected resource users at the local and regional level.     

Effects of Metal Mining and Milling on Boundary Waters of Yellowstone National Park, USA

/ Aquatic resources in Soda Butte Creek within Yellowstone National Park, USA, continue to be threatened by heavy metals from historical mining and milling activities that occurred upstream of the park's boundary. This includes the residue of gold, silver, and copper ore mining and processing in the early 1900s near Cooke City, Montana, just downstream of the creek's headwaters. Toxicity tests, using surrogate test species, and analyses of metals in water, sediments, and macroinvertebrate tissue were conducted from 1993 to 1995. Chronic toxicity to test species was greater in the spring than the fall and metal concentrations were elevated in the spring with copper exceeding water quality criteria in 1995. Tests with amphipods using pore water and whole sediment from the creek and copper concentrations in the tissue of macroinvertebrates and fish also suggest that copper is the metal of concern in the watershed. In order to understand current conditions in Soda Butte Creek, heavy metals, especially copper, must be considered important factors in the aquatic and riparian ecosystems within and along the creek extending into Yellowstone National Park.KEY WORDS: Mining; Metals; Toxicity; Biomonitoring; Copper; Yellowstone National Park     

The value of agricultural wetlands as invertebrate resources for wintering shorebirds

Agricultural landscapes have received little recognition for the food resources they provide to wintering waterbirds. In the Willamette Valley of Oregon, modest yet significant populations of wintering shorebirds (Charadriiformes) regularly use hundreds of dispersed wetlands on agricultural lands. Benthic invertebrates are a critical resource for the survival of overwintering shorebirds, yet the abundance of invertebrate resources in agricultural wetlands such as these has not been quantified. To evaluate the importance of agricultural wetlands to a population of wintering shorebirds, the density, biomass, and general community composition of invertebrates available to birds were quantified at a sample of Willamette Valley sites during a wet (1999–2000) and a dry winter (2000–2001). Invertebrate densities ranged among wetlands from 173 to 1925 (mean ± S.E.: 936 ± 106) individuals/m² in the wet winter, and from 214 to 3484 (1028 ± 155) individuals/m² in the dry winter. Total invertebrate estimated biomass among wetlands ranged from 35 to 652 (mean ± S.E.: 364 ± 35) mg/m² in the wet winter, and from 85 to 1405 (437 ± 62) mg/m² in the dry winter. These estimates for food abundance were comparable to that observed in some other important freshwater wintering regions in North America.     

湿地甲烷释放研究进展

甲烷是一种重要的温室气体，近年来大气甲烷浓度显著增加，湿地甲烷释放量约占全球总释放量的２１％，因而是大气甲烷的主要来源之一。本文综述了湿地甲烷产生，释放和氧化过程以及影响因素，以便为国内湿地甲烷排放研究提供借鉴。     

洞庭湖区的湿地资源及保护对策

介绍了洞庭湖区湿地类型、分布、湿地生态资源现状,指出了洞庭湖区湿地生态系统所存在的主要问题并对其保护对策,提出合理建议.     

红树林生态系统服务功能及其保护

红树林有多种生态系统服务功能，包括促进渔业生产，护岸减灾，保护生物多样性，改善环境质量等，中国红树植物种类少，分布范围窄，资源面积小，质量差，尤其人类活动加剧了其脆弱和濒危程度，近年程度工作有一定进展，资源有所恢复，但仍需正确处理沿海地区发展和红树林生态系统保护的关系，在国土资源保护中给予红树林最高保护等级的地位。     

Microtopographic modification conserves urban wetland water quality by increasing the dissolved oxygen in the wet season

Microtopography affects hydrological processes and forms different microhabitats. Our previous study uncovered that riparian zone microtopography created various microhabitats with different soil environments and runoff-infiltration patterns. However, how riparian microtopography and microtopography within the water area (waterfall and tributary) affects downstream water quality remains unclear. Therefore, water samples were taken almost monthly in both the main stream and the tributary, before and after waterfalls, and near the bottom of three microtopographic types from June 2016 to March 2017. Compared with the dry season, the fact that water quality worsened in the wet season and that there were positive correlations for nitrate (NO₃^?) between water and the corresponding soil samples suggested that the riparian-soil environment affected the adjacent water quality mainly in the wet season. Nevertheless, riparian microtopography did not influence water quality downstream because of the low rainfall frequency and the weak leaching process due to plant interception. In the wet season, both the tributary and the waterfall increased the dissolved oxygen in the water body and, therefore, lowered the risk of eutrophication. The tributary has two pathways for improving the water quality, by increased disturbance and flow velocity, while the waterfall only has the former. However, such effects were not significant in the dry season. We conclude that the application of microtopographic modification is useful in maintaining urban wetland water quality in wet seasons.