氮磷添加对红壤区城郊湿地松林凋落叶分解的影响

城市化易导致城市森林氮(N)沉降和磷(P)富集,进而对凋落物分解过程产生影响。以位于南昌市郊的湿地松(Pinuse lliottii Engelm.)林为研究对象,采用尼龙网袋分解法,模拟N沉降(10g N·m-2·a-1,[N])、P积累(2.5g P·m-2·a-1,[P])和N沉降+P积累(10N·m-2·a-1+2.5g P·m-2·a-1,[N+P])对凋落叶分解速率与C、N、P含量及其化学计量比动态变化的影响。结果表明:与对照(CK)相比,[N]、[P]和[N+P]均促进凋落叶的前期(0～180d)分解速率,抑制中期(180～360d)、后期(360～540d)的分解速率;至540d时分解速率表现为[N]、[P]和CK无差异,但均高于[N+P](P0.05)。[N]提高分解过程中凋落叶N浓度,N含量表现为分解前期积累、后期释放;[P]提高分解过程中凋落叶P浓度,P含量持续积累;[N+P]提高N和P浓度,分解前期N、P含量积累,后期释放;而不同处理的C含量均表现为释放。凋落物基质C/N/P比与分解速率的相关性随分解阶段而表现各异。综合来看,城市化导致的N沉降和P富集叠加效应具有抑制城市森林凋落物分解过程的潜在性。     

Biodiversity and distribution of polychaetes and molluscs along the Dese estuary (Lagoon of Venice, Italy)

Mollusc and polychaete distribution in the mud flats along the Dese estuary (lagoon of Venice, Italy) was analysed in May, August and October to evaluate taxonomic biodiversity and zonation pattern of soft macrobenthos in an area of the lagoon hardly known from this point of view. Throughout the studied area most of the species were polychaetes, particularly Streblospio shrubsolii (Buchanan), which showed greater abundance from May to October. Molluscs and polychaetes showed a zonation of marine species which colonize brackish environments in the outer and intermediate areas of the estuary and of brackish water species in the inner one. In the outer area different assemblages were attributed to different sediment types. This distribution pattern, put in relation to the distance from the sea, was evident in May and partly blurred in August and October: the assemblages of the inner area of the estuary invaded the intermediated area in August and affected outer area in October because of spreading of the brackish water species S. shrubsolii, which became dominant. The distribution pattern of molluscs and polychaetes can be explained in terms of confinement as the leading factor influencing water quality and dynamics of the ecosystem. It is also needed to be taken into consideration the role played by competition due to different degree of opportunism of the most abundant species.     

Hierochloë odorata (L.) Beauv. confermata per la flora italiana

Abstract

On the presence of Hierochloë odorata (L.) Beauv. in Italy.—H. odorata has been found in an oligotrophic marsh in the Italian part of the Eastern Alps and therefore definitively confirmed for the flora of Italy. An extended population occurs at 1800 m above sea level near Misurina, in the Dolomites (province of Belluno). All preceding records of H. odorata for the Italian flora must be referred to H. australis (Schrader) R.&S. Differential characters and distribution of the two species are shortly discussed.     

河流生态学研究中的几个热点问题

近年来河流生态系统成为湖沼学研究的重点,很多新理论、新方法被应用到研究中．文章综述了国内外的相关研究,并着重从河流连续、河流的生态需水量、河流生态系统的服务价值与健康评价、河流的生态系统管理以及流域生态学等几个热点方向作了详细论述．作者认为,今后河流生态学的研究应在流域尺度上展开,结合河流健康及生态系统服务评价进行河流生态系统可持续管理研究将是近期河流生态学的重点问题之一．鉴于我国的实际情况,作者建议应该尽快开展相关领域的研究．     

Does habitat heterogeneity affect the diversity of epigaeic arthropods in vineyards?

1. The aims of this research performed in vineyards within the Douro Demarcated Region were to determine the species composition of vineyard epigaeic arthropods assemblages and to determine the influence of certain factors on their activity densities and diversity: (i) landscape composition in buffers (125, 250, 500 and 750 m) around each study site; (ii) adjacent vegetation; and (iii) vineyards' ground cover. Arthropods' were assessed using pitfall traps located inside the vineyards at three distances from adjacent vegetation (5, 50 and 100 m).
2. Activity densities and diversity increased from spring to summer for all the studied trophic groups (omnivores, detritivores, predators, phytophages), thus showing them to be affected by season.
3. The activity densities of phytophages were always higher at a distance of 5 m from the adjacent vegetation, which suggests that, although they could originate from these habitats, they do not move too far into the vineyard. Predators reported higher activity densities at 5 m during spring. Meanwhile, in summer, no significant differences were found with the increasing distance from the edge. This result suggests that these habitats could serve both as a refuge and a hibernation habitat, from which predators could colonize the vineyard.

     

Distribution and production of macrophytes and phytoplankton in the lagoon of Venice: comparison of actual and past situation

This paper aims at comparing inedited maps of macrophytes and phytoplankton distribution in the lagoon of Venice in 1980 and 2003. The macrophyte distribution is displayed with reference to different biomass intervals which allow the calculation of the occupied surface, standing crop (SC), net (NPP) and gross (GPP) production. In 1980 the total macroalgal SC was ca. 841 ktonnes whereas the annual NPP and GPP were estimated to be ca. 2912 and 18498 ktonnes, respectively. In 2003 macroalgae displayed a marked regression and the SC, NPP and GPP decreased to ca. 89, 471 and 2336 ktonnes. Maps of the seagrass distribution date back to 1990 but their biomass and production have been quantified only in 2003. On the whole, in 2003, on a surface of ca. 56 km2 the three species living in the lagoon accounted for a SC and a NPP of ca. 209 and 821 ktonnes, whereas the GPP estimated according to literature was about twice as high as the NPP. Cymodocea nodosa was the most abundant phanerogam in the lagoon. Its SC was higher than the total of the macroalgae, although the latter were more productive. Zostera marina covered the highest surface in the lagoon but its biomass and production were a little lower than that of C. nodosa. Nanozostera noltii, which was common and widespread in the past, displayed an evident regression trend which was mainly due to the increase of the water turbidity and the disruptions of its habitat. Similarly, phytoplankton, underwent a descending trend, although data quoted in the present paper display its distribution only in the summer period.     

How ecological engineering can serve in coastal protection

Traditionally, protection of the coastal area from flooding is approached from an engineering perspective. This approach has often resulted in negative or unforeseen impacts on local ecology and is even known to impact surrounding ecosystems on larger scales. In this paper, the utilization of ecosystem engineering species for achieving civil-engineering objectives or the facilitation of multiple use of limited space in coastal protection is focused upon, either by using ecosystem engineering species that trap sediment and damp waves (oyster beds, mussel beds, willow floodplains and marram grass), or by adjusting hard substrates to enhance ecological functioning. Translating desired coastal protection functionality into designs that make use of the capability of appropriate ecosystem engineering species is, however, hampered by lack of a generic framework to decide which ecosystem engineering species or what type of hard-substrate adaptations may be used where and when. In this paper we review successful implementation of ecosystem engineering species in coastal protection for a sandy shore and propose a framework to select the appropriate measures based on the spatial and temporal scale of coastal protection, resulting in a dynamic interaction between engineering and ecology. Modeling and monitoring the bio-physical interactions is needed, as it allows to upscale successful implementations and predict otherwise unforeseen impacts.     

‘Ecosystem service opportunities’: A practice-oriented framework for identifying economic instruments to enhance biodiversity and human livelihoods

Economic instruments that promise “win-win” solutions for both biodiversity conservation and human livelihoods have become increasingly popular over recent years. There however remains a gap in terms of practical and policy-relevant guidance about appropriate approaches that take into account the local needs and the specific cultural, legal, and ecological context in which such instruments are being developed and applied. This paper presents a step-by-step framework that helps conservation and development planners and practitioners to identify economic instruments that can promote pro-conservation behaviour in a specific setting. The concept of ‘ecosystem service opportunities’ builds on, and brings together, general economic principles and an ecosystem services perspective. The framework was designed to also address a number of concerns regarding economic approaches in order to help practitioners recognise the potentials and limits of economic approaches to nature conservation. The framework is illustrated by its application within the realm of a biodiversity conservation project in Thailand.     

The introduced alga Undaria pinnatifida (Laminariales,Alariaceae) in the lagoon of Venice

Since its appearance in 1992 in the lagoon of Venice, the brown algae Undaria pinnatifida (kelp) has gradually expanded along the banks of canals both at Chioggia and Venice, becoming the dominant species in the local algal community chiefly from February to July. In Chioggia Island, where another brown seaweed (Sargassum muticum) is present since 1992, the spreading of Undaria reaches a plateau. In Venice Island, instead, the colonisation process is still in progress. During 1999, the kelp has colonised the main canals (e.g. The Grand Canal) and, subsequently, the small inner ones. In order to evaluate the dynamics of substrate re-colonisation by Undaria, two mechanical eradications were carried out during (March) and after the fertile period (July) of the algae. Such experimental manipulations provided evidence of the fast re-colonisation potential of the algae mainly attributable to its efficient reproductive system. Eradication made during the fertile period, in fact, permitted the kelp development during the following year, while re-colonisation has started 2 years later where eradication was performed after the reproductive period. A significant decrease in the surface covered by other species has been observed both in shallow (Ulva rigida, Enteromorpha spp., Antithamnion pectinatum, Chondracanthus acicularis) and deeper areas (Rhodymenia ardissonei) during the period of maximum development of U. pinnatifida. On the basis of the results of this study, the following conclusions can be drawn: (1) the alga U. pinnatifida is continuously expanding in lagoon environments of Venice; (2) in order to limit its spreading, mechanical eradications would be done on a large spatial scale and before the zoospores release; (3) there is suggestive evidence of competition between Undaria and the remaining indigenous algae.