Aquatic Habitat Dynamics along a Braided Alpine River Ecosystem (Tagliamento River, Northeast Italy)

Aquatic habitat change caused by flooding was quantified along the Fiume Tagliamento, a morphologically intact gravel-bed river ecosystem in northeast Italy. Five different geomorphic reaches (each around 1.5 km), ranging from near the headwaters at 800 m above sea level (a.s.l.) to near the mouth at 5 m a.s.l., were studied over a 1-year period. All floodplain water bodies in each reach were delineated in August 1999 using a differential global positioning system. Each reach was remapped twice (in December 1999 and August 2000) to investigate the impact of autumn and spring flood seasons on aquatic habitat composition and configuration. A high degree (nearly 62%) of aquatic habitat turnover was documented in a braided headwater floodplain. The degree of aquatic habitat turnover decreased with decreasing elevation to approximately 20% turnover in a meandering reach at 5 m a.s.l. In contrast to turnover, braiding, sinuosity, and aquatic habitat composition changed little in response to flooding in all reaches. Location of aquatic habitats in floodplains changed considerably (turnover), whereas habitat configuration and composition remained relatively stable. These results support the applicability of the shifting mosaic steady-state model to riverine floodplain environments.     

Thermal Heterogeneity in River Floodplains

River floodplains are composed of a shifting mosaic of aquatic and terrestrial habitats. Each habitat type exhibits distinct environmental and ecological properties. Temperature is a key property driving ecological processes and controlling the composition and distribution of biota. However, given the size and complexity of floodplains, ground surveys based on point measurements are spatially limited. In this study, we applied thermal infrared (IR) imagery to quantify surface temperature patterns at 12–15 min intervals over 24 h cycles in two near-natural Alpine river floodplains (Roseg, Tagliamento). Furthermore, vertical temperature distribution was measured at 3–5 min intervals in unsaturated gravel sediment deposits (at 1 cm distances; 0–29 cm depth). Each habitat type exhibited a distinct thermal signature creating a complex thermal mosaic. The diel temperature pulse and maximum daily temperature were the main thermal components that differentiated habitat types. In both floodplains, exposed gravel sediments exhibited the highest diel pulse (up to 23°C), whereas in aquatic habitats the pulse was as low as 11°C (main channel in the Roseg floodplain). In the unsaturated gravel sediment deposits, the maximum diel kinetic temperature pulse ranged from 40.4°C (sediment surface) to 2.7°C (29 cm sediment depth). Vertically, the spatiotemporal variation of temperature was about as high as horizontally across the entire floodplain surface. This study emphasized that remotely sensed thermal IR imagery provides a powerful non-invasive method to quantitatively assess thermal heterogeneity of complex aquatic and terrestrial ecosystems at a resolution required to understand ecosystem processes and the distribution of biota.     

Spatiotemporal heterogeneity of soil and sediment respiration in a river‐floodplain mosaic (Tagliamento,NE Italy)

1. In their natural state, river floodplains are composed of a complex mosaic of contrasting aquatic and terrestrial habitats. These habitats are expected to differ widely in their properties and corresponding ecological processes, although empirical data on their capacity to produce, store and transform organic matter and nutrients are limited. 2. The objectives of this study were (i) to quantify the spatiotemporal variation of respiration, a dominant carbon flux in ecosystems, in a complex river floodplain, (ii) to identify the environmental drivers of respiration within and among floodplain habitat types and (iii) to calculate whole‐floodplain respiration and to put these values into a global ecosystem context. 3. We measured soil and sediment respiration (sum of root and heterotrophic respiration; SR) throughout an annual cycle in two aquatic (pond and channel) and four terrestrial (gravel, large wood, vegetated island and riparian forest) floodplain habitat types in the island‐braided section of the near‐natural Tagliamento River (NE Italy). 4. Floodplain habitat types differed greatly in substratum composition (soil to coarse gravel), organic matter content (0.63 to 4.1% ash‐free dry mass) and temperature (seasonal range per habitat type: 8.6 to 33.1 °C). Average annual SR ranged from 0.54 ± 1.56 (exposed gravel) to 3.94 ± 3.72 μmol CO₂ m^?2 s^?1 (vegetated islands) indicating distinct variation in respiration within and among habitat types. Temperature was the most important predictor of SR. However, the Q₁₀ value ranged from 1.62 (channel habitat) to 4.57 (riparian forest), demonstrating major differences in habitat‐specific temperature sensitivity in SR. 5. Total annual SR in individual floodplain habitats ranged from 160 (ponds) to 1205 g C m^?2 (vegetated islands) and spanned almost the entire range of global ecosystem respiration, from deserts to tropical forests.     

Market-resource Links and Fish Vendor Livelihoods in the Upper Zambezi River Floodplains

This paper examines small-scale fish vending in a southern African floodplain from two perspectives: as a link between natural resource use and consumption, and as a livelihood in itself. We used a combination of observation, surveys and semistructured interviews in a market in Katima Mulilo, Namibia, to determine sources of fish, preferences and constraints to vending, average investment and profit, as well different routes into fish vending and perceptions regarding vending. Most vendors come from fishing households, but their stock is often an accumulation of purchases from other fishers. There is little evidence of formal arrangements between fishers and vendors, yet most adapt to the highly variable natural and social environments of the region. Although all vendors ranked selling fish as their most important livelihood activity, a wide range of investment and profit exists among individuals. Our findings indicate that fisheries management proposed for the area must be developed with a careful understanding of how changes in access and use will affect vending livelihoods.

Succession and Rejuvenation in Floodplains along the River Allier (France)

The spatio-temporal heterogeneity of a meandering part of the Allier river was studied by analysing ecotope composition and dynamics using a series of aerial images covering a period of 46 years (1954–2000). The ecotope dynamics was exemplified by two time series showing rejuvenating hydro-geomorphological processes, i.e., meander progression, meander cut-off and channel shift. The mean rejuvenation rate was 33.8 ha per 5 years for the 5.5 km long study area. The ecotope transition rates varied from 18% surface area change per 5 years to 58.7% surface area change per 5 years for pioneer vegetation. The combination of hydro-geomorphological processes and ecological succession resulted in a temporal diversity of the riparian area. In the year 2000 half of the total riparian landscape was 14 years or younger and 23% was not rejuvenated in 46 years. Eighty percent of the pioneer vegetation was found on young soils (<14 years) while more than 50% of the surface area of low dynamic ecotopes like bush and side channels was located on parts, which were stable for more than 46 years. Examining the relation between river stretch size and ecotope diversity showed that the ecotope diversity remained stable above a stretch size of 1.5 meander lengths for the years 1978, 1985 and 2000. The spatial and temporal analysis of the study area showed evidence supporting the steady state or meta-climax hypotheses, but influences of long-term processes on landscape composition were also found. Some implications for floodplain management are discussed.     

Biogeochemical Constraints on the Ecological Rehabilitation of Wetland Vegetation in River Floodplains

The European policy for river management during peak discharge periods is currently changing from exclusion strategies (reinforcement of dykes) to allowing a more natural situation by creating more floodplain space to reduce water levels during peak discharges. In addition, water retention and water storage areas have been created. The new measures are generally being combined with nature development strategies. Up till now, however, ecological targets of broadscale floodplain wetland restoration including sedge marshes, species-rich floodplain forests and carrs, riparian mesotrophic grasslands and other biodiverse riverine ecosystems, have hardly developed in these areas. Most studies on the conditions needed for sustainable ecological development of floodplains have focused on hydrological and geomorphological rather than biogeochemical issues (including nutrient availability and limitation). There are, however, large differences in the composition of river water and groundwater and in sediment quality between rivers in densely populated areas and those in more pristine areas, which serve as a reference. It is very likely that these factors, in combination with heavily altered hydrological regimes and the narrow areas confined between the dykes on both sides of the rivers, impose major constraints on sustainable ecological development of riverine areas. Another issue is that existing wetlands are generally considered to be very appropriate for water retention and conservation, although recent research has shown that this may pose a serious threat to their biodiversity. The present paper reviews the biogeochemical constraints on the combination of floodplain rehabilitation, water conservation and the conservation and development of wetlands. It is concluded that biogeochemical problems (mainly related to eutrophication) predominantly arise in less dynamic parts of the river system, to which the flood-pulse concept applies less. Sound knowledge of the biogeochemical processes involved will contribute to greater efficiency and a better prediction of the opportunities for restoration and development of riverine wetlands. This information can be directly applied in nature management, water management, policy-making and consultancy.     

The role of timing, duration, and frequency of inundation in controlling leaf litter decomposition in a river-floodplain ecosystem (Tagliamento, northeastern Italy)

Despite growing recognition of the importance of a natural flow regime in river-floodplain systems, researchers struggle to quantify ecosystem responses to altered hydrological regimes. How do frequency, timing, and duration of inundation affect fundamental ecosystem processes such as leaf litter decomposition? Along the semi-natural Tagliamento River corridor, located in northeastern Italy, we employed in situ experiments to separate effects of different inundation components on breakdown rates of black poplar (Populus nigra). We used a litter-bag method with two different mesh sizes to investigate how fungi and macroinvertebrates influence leaf breakdown rates. Ten treatments, each representing a specific combination of duration and frequency of inundation, were deployed in two seasons (summer, winter) to mimic complex inundation patterns. After 30 days of exposure, mean percentage of remaining leaf litter (ash free dry mass) ranged between 51% (permanent wet) and 88% (permanent dry). Leaf breakdown was significantly faster in winter than in summer. Duration of inundation was the main inundation component that controlled leaf breakdown rates. Leaf-shredding macroinvertebrates played only a role in the permanent wet treatment. Fungal parameters explained the faster leaf breakdown in winter. Our study suggests that modifications of the inundation regime will directly modify established decomposition processes. Factors reducing duration of inundation will decelerate leaf breakdown rates, whereas a decrease in flow variation will reduce leaf breakdown heterogeneity.     

Dynamics of a benthic microbial community in a riverine environment subject to hydrological fluctuations (Mulargia River,Italy)

Temporary rivers are characterized by recurrent dry phases, and global warming will stress their hydrology by amplifying extreme events. Microbial degradation and transformation of organic matter (OM) in riverbed sediment are key processes with regard to carbon and nutrient fluxes. In this study, we describe structural and functional changes of benthic microbial communities in a riverine environment subject to hydrological fluctuation. Sampling was carried out in the outlet section of the Mulargia River (Sardinia, Italy) under various water regimes, including one flood event. Overall, sediments were characterized by low bacterial cell abundance (range 0.6–1.8 × 10⁹ cell g⁻¹) as a consequence of their low nutrient and OM concentrations. No major differences were found in the community composition. Alpha-Proteobacteria dominated during the whole year (range 21–30%) followed by Beta-Proteobacteria, Gamma-Proteobacteria, and Cytophaga-Flavobacteria which always contributed <18%. Planctomycetes and Firmicutes were found in smaller amounts (<7%). In spring, when the highest total organic carbon content was also detected (0.42% w/w), both bacterial abundance and C production (BCP, 170 nmol C h⁻¹ g⁻¹) reached relatively high values. During the flood event, an increase in BCP and the highest values of community respiration (CR, 74 nmol C h⁻¹ g⁻¹) were observed. Moreover, most of the extracellular enzyme activities (EEA) changed significantly during the flood. The variation of the water flow itself can explain part of these changes and other factors also come into play. The presence of different patterns of functional parameters could suggest that the quality of the OM could be the major driving force in nutrient flux.     

Zooplankton in the Floodplains of a Tributary to the Paraná River in Mato Grosso Do Sul,Brazil

Zooplankton samples were taken monthly at five sites March 1992 through February 1993 of the Guaraná lake and Baía river in the Paran floodplain, Brazil. A total of 38 cladoceran and 12 copepod species was identified. Cladocerans were mainly collected amongst macrophytes in the lake. The most commonly encountered species were Bosminopsis deitersi, Moina minuta, Ceriodaphnia cornuta, Ilyocryptus spinifer, Macrothrix spinosa, and Phryxura dadayi. The copepods were especially collected in the river with Thermocyclops minutus and Mesocyclops meridianus being abundant. The greatest number of microcrustacean species was detected during the high water period. Possible ecological conditions for the recorded distribution and abundance are discussed and compared with data from other study sites in the Neotropics.     

Green Tongues into the Arid Zone: River Floodplains Extend the Distribution of Terrestrial Bird Species

Floodplain and riparian ecosystems have cooler, wetter microclimatic conditions, higher water availability and greater vegetation biomass than adjacent terrestrial zones. Given these conditions, we investigated whether floodplain ecosystems allow terrestrial bird species to extend into more arid regions than they otherwise would be expected to occupy. We evaluated associations between aridity and the occurrence of 130 species using bird survey data from 2998 sites along the two major river corridors in the Murray–Darling Basin, Australia. We compared the effects of aridity on species occurrence in non-floodplain and floodplain ecosystems to test whether floodplains moderate the effect of aridity. Aridity had a negative effect on the occurrence of 58 species (45%) in non-floodplain ecosystems, especially species dependent on forest and woodland habitats. Of these 58 species, the negative effects of aridity were moderated in floodplain ecosystems for 22 (38%) species: 12 showed no association with aridity in floodplain ecosystems and the adverse effects of aridity on species occurrence were less pronounced in floodplain ecosystems compared to non-floodplain ecosystems for ten species. Greater vegetation greenness indicated that floodplain vegetation was more productive than vegetation in non-floodplain ecosystems. Floodplain ecosystems allow many terrestrial species to occur in more arid regions than they otherwise would be expected to occupy. This may be due to higher vegetation productivity, cooler microclimates or connectivity of floodplain vegetation. Although floodplain and riparian ecosystems will become increasingly important for terrestrial species persistence as climate change increases drying in many parts of the world, many are also likely to be highly affected by reduced water availability.     

Habitat change in braided flood plains (Tagliamento, NE-Italy)

1. Relative changes and age distribution of habitats were investigated in the active channel of a bar‐braided and an island‐braided reach of the Tagliamento River (NE‐Italy). Between September 1999 and January 2002, six habitat types were delineated with a differential Global Positioning System on five dates following floods of different magnitude. Overlay maps were employed to calculate age and relative change of habitats. We established exponential decay rates (k‐values) for islands and major aquatic habitats. 2. Relative changes of all aquatic habitats combined were up to 82% between survey dates in the bar‐braided flood plain, with a cumulative rate of 85% over the 2.5‐year period. Relative habitat changes in the island‐braided flood plain were lower with a cumulative change of almost 60% during the study period. In the bar‐braided flood plain significant exponential decay relationships were established for channels, alluvial channels, backwaters, and ponds. 3. Half‐lives were particularly short for backwaters and ponds. In the island‐braided reach, significant relationships existed for channels and alluvial channels. The half‐lives of channels and alluvial channels increased with the presence of vegetated islands. Relative habitat composition within the active corridor remained almost constant, supporting the applicability of the shifting mosaic steady state model to braided floodplain ecosystems. 4. Our results indicate that under natural conditions aquatic floodplain habitats can be highly dynamic over short time‐scales. Even small water level fluctuations (‘flow pulses’) can lead to major habitat changes with important consequences for the fauna and flora.     

Forecasting Temporal Dynamics of Cutaneous Leishmaniasis in Northeast Brazil

Introduction

Cutaneous leishmaniasis (CL) is a vector-borne disease of increasing importance in northeastern Brazil. It is known that sandflies, which spread the causative parasites, have weather-dependent population dynamics. Routinely-gathered weather data may be useful for anticipating disease risk and planning interventions.

Methodology/Principal Findings

We fit time series models using meteorological covariates to predict CL cases in a rural region of Bahía, Brazil from 1994 to 2004. We used the models to forecast CL cases for the period 2005 to 2008. Models accounting for meteorological predictors reduced mean squared error in one, two, and three month-ahead forecasts by up to 16% relative to forecasts from a null model accounting only for temporal autocorrelation.

Significance

These outcomes suggest CL risk in northeastern Brazil might be partially dependent on weather. Responses to forecasted CL epidemics may include bolstering clinical capacity and disease surveillance in at-risk areas. Ecological mechanisms by which weather influences CL risk merit future research attention as public health intervention targets.     

Bacterial Abundance, Activity, and Viability in the Eutrophic River Warnow, Northeast Germany

The River Warnow is the drinking water source for the city of Rostock. Its eutrophic status is accompanied by high amounts of bacteria, which may reach up to 24 x 10(6) cells mL(-1) as recorded during a seasonal study in 2002. Because the river is eutrophic and also heavily loaded with organic matter, this burden is a problem for drinking water purification, as it must be removed completely to not trigger new bacterial growth in the pipeline network. Therefore, restoration measures in the river have to be planned, and bacteria have to be favored as decomposers. That includes the investigation of the physiological state of bacteria in situ. Viable and active cells in the lower reaches of River Warnow were estimated using a broad set of methods. Intact bacteria were investigated by the LIVE/DEAD BacLight bacterial viability kit, containing a mixture of permeant and impermeant nucleic acid stains. Cells with ribosomes were visualized by fluorescence in situ hybridization with the EUB338 oligonucleotide probe. Intact cells and ribosome-containing bacteria represented 24% of total numbers stained by 4'6,-diamidino-2-phenylindole (DAPI) or 66 and 62%, respectively, in relation to all bacteria visualized by the LIVE/DEAD kit. Both fractions were considered as viable, although the fraction of RIB + bacteria is most likely underestimated by the protocol applied. 5-Cyano-2,3-ditolyltetrazolium chloride (CTC) was applied to mark respiring bacteria. The esterase substrate CellTracker Green 5-chloromethylfluorescein diacetate showed cells with intracellular hydrolytic activity. Whereas 1.5% of DAPI-stained bacteria were observed as respiring, 3.8% exhibited intracellular hydrolytic activity on average. If these active fractions were calculated as the percentages of intact cells, much higher fractions of 5.4% were respiring and 16% hydrolytic. Temperature was a main factor influencing total and viable cell numbers simultaneously. The results confirm that there are different states of viable and active cells in natural bacterioplankton communities. However, it remains unclear why fractions of viable and active cells were rather low in this eutrophic river in comparison to similar waters. We recommend to carefully address cells as viable in contrast to nonviable, i.e., dead. As viable cells may be active or inactive with respect to many different activities, e.g., substrate uptake, respiration, hydrolysis, and cell deviation, it is necessary to choose the method to visualize active cells according to the question to be answered.     

Plant Succession on the Braided Bed of the Orongorongo River, Wellington, New Zealand, 1973-1990

Vegetation on 5 km (c. 100 ha) of the braided bed of the Orongorongo River, Wellington, was sampled in March from 1973 to 1990. The riverbed has become aggraded since an earthquake in 1855. Surface water covered little of the riverbed; Callitriche stagnalis was the only common vascular aquatic plant. Most grasses and dicot herbs were adventive. The scabweed Raoulia tenuicaulis was the commonest dicot. The extent of plant cover was measured on 300 circular plots (radius 1.5 m); it ranged between years from 5% to 22%, depending on the severity of floods. The number of plots with little vegetation varied widely, independently of plant cover. Plots with a sandy substrate had most plant cover. Much wind- blown sand accumulated beneath established vegetation. Patterns of early succession, which relied on available seed, were largely dictated by floods and droughts. If not disturbed for 20-25 years, succession invariably led to a temporary dominance of kanuka (Kunzea ericoides), with or without manuka (Leptospermum scoparium).     

绥芬河大麻哈鱼增殖放流效果评估

为评估绥芬河大麻哈鱼增殖放流效果,本研究于2012—2017年在绥芬河东宁段对大麻哈鱼溯河洄游群体进行跟踪监测.共采集样本462尾,其中,标记个体(剪脂鳍)41尾.根据调查数据,计算了大麻哈鱼增殖放流回捕率,评估了增殖放流效果.结果表明: 2010—2012年的大麻哈鱼增殖放流回捕率为0.295%,大麻哈鱼增殖放流数量效益为1∶2.87.标记组和非标记组群体年龄组均为1⁺～5⁺龄,平均年龄分别为3.93和3.63龄.采用Logistic 曲线方程计算标记组和非标记组大麻哈鱼的50%初次性成熟叉长(L₅₀)分别为53.13和49.89 cm.ARSS分析结果显示,大麻哈鱼两组群体的叉长生长差异不显著,但两组间的性成熟比例差异显著.本研究表明大麻哈鱼增殖放流对其资源增殖保护具有重要作用,为今后增殖放流工作提出了建议.     

浑太森林流域径流过程模拟

基于浑河与太子河上游1998-2007年北口前站和南甸峪站水文数据以及清原、新宾和本溪县气象站点同期气象数据,应用DHSVM分布式水文模型模拟浑太流域的水文过程,验证模型的科学适用性,并提供最敏感模型参数的参考值.结果表明：浑河源区月径流模拟的Nash-Suttclife系数(E值)在率定期(1998-2002年)和验证期(2003-2007年)分别达到0.9675和0.8957,较好重现了研究区的月径流过程.太子河上游流域的年、月径流模拟值的E值均大于0.6,说明模型在浑太流域有较好的适用性、率定的参数方案有良好的可靠性.本文为无站点观测资料的流域水文研究建立了一个坚实的框架,并构建了合理的参数方案.     

长白山森林动态监测样地鸟兽的红外相机初步监测

<正>长白山国家级自然保护区(41o41′49″–42o25′18″N,127o42′55″–128o16′48″E)位于吉林省东部,面积为196,465 ha,设立于1960年,并于1980年被列为联合国教科文组织世界生物圈自然保护区。保护区内植被垂直带明显,包括针阔混交林(1,100 m以下)、暗针叶林(1,100–1,800 m)、亚高山岳桦(Betula ermanii)林(1,800–2,000 m)和高山苔原(2,000–2,700m)等4个植被带,其中阔叶红松林为该区域的地带性植被(代力民等,2004)。长白山地区野生动植物资源十分丰富,有被子植物98科454属1,190种,兽类     

Incidence and Estimated Prevalence of Endometriosis and Adenomyosis in Northeast Italy: A Data Linkage Study

Despite being quite frequent and having serious implications in terms of symptomatology and fertility, data on incidence and prevalence of endometriosis and adenomyosis following gold standard definitions are dramatically lacking. The average time from onset of symptoms to diagnosis in industrialized countries still ranges from five to ten years. Using the regional centralized data linkage system, we calculated incidence and prevalence of endometriosis and adenomyosis in the female population of Friuli Venezia Giulia region, Italy, for the years 2011–2013. Cases were defined as new diagnoses from hospital discharge records, following procedures allowing direct visualization for endometriosis and hysterectomy for adenomyosis, with or without histological confirmation. Diagnoses were considered “new” after verifying women had not been diagnosed in the previous ten years. Incidence of endometriosis and adenomyosis in women aged 15–50 years is 0.14%. Prevalence, estimated from incidence, is 2.00%. Adenomyosis, representing 28% of all diagnoses, becomes increasingly prevalent after the age of 50 years. Our results shows how the study of both endometriosis and adenomyosis should not be limited to women of premenopausal age. Further efforts are needed to sensitize women and health professional, and to find new data linkage possibilities to identify undiagnosed cases.