Organic and integrated agriculture: the effects on bird communities in orchard farms in northern Italy

The objective of this study was to compare the effects of different farming methods on bird communities. In particular, the study surveyed the frequency and number of bird species, the number of individuals and bird diversity (Shannon index) found in organic (o, non use of synthetic pesticides), integrated (i, reduced use of pesticides on the basis of the economic threshold) and conventional (c, conventional use of pesticides) orchards. A simplified version of the mapping method was applied, from May to June 1998, to 60 fruit farms (15o, 19 i, 26c), over a total of 483 ha. Twenty-six bird species were observed (19o, 17i, 18c). Granivorous species were the most abundant and unaffected by pesticide management. Insectivorous species were less abundant in general, but more frequent on o and i farms (chi-square test, p<0.05). Bird diversity was greater in o and i farm management than in c (Tukey test, respectively, p = 0.001 and 0.004). There was a non-significant trend for bird density to be higher in o/i than c orchards (ANOVA, F _2.57 = 2.76, p = 0.07). The results confirm the positive effects of (o) and (i) agriculture on bird communities, including some species of special interest for nature conservation. These effects could be attributed mostly to the different pest management and secondarily to some aspects of environmental differentiation (type of orchard, type of farm, age and height of trees, and increased presence of hedgerows and woodlots). Surprisingly no correlation was observed between hedgerows and woodlots and bird diversity (Pearson test, R = 0.0019).     

Performance evaluation of eight years experience of constructed wetland systems in Catalonia as alternative treatment for small communities

In Catalonia (Spain), a variety of different systems have been built to naturally treat liquid residues from small communities. Some of these wastewater treatment plants (WWTPs) include constructed wetlands with horizontal subsurface flow (HSSF) as secondary treatment. The present study described and characterized the performance of 11 WWTPs with secondary HSSF constructed wetland systems after an initial operating period of 8 years. The effluent concentrations of Biochemical Oxygen Demand (BOD₅), Total Suspended Solids (TSS), Total Nitrogen (TN) and Total Phosphorous (TP) were statistically analyzed, and removal efficiencies for all WWTPs including all stages in treatment were calculated. The accumulated probability functions of those parameters were evaluated to determine the influence of two different types of polishing units on the overall performance: (a) only lagoon systems and (b) lagoon systems with HSSF. The statistical analysis indicates good performance for BOD₅ and TSS. In the first case, mean concentrations below 25 mg/L were found in 9 of the 11 plants analyzed and removal efficiencies between 78 and 96% were observed. In the second case, mean concentrations below 35 mg/L were found in 8 of the 11 plants, and removal efficiencies were between 65 and 88%. For the nutrients, the removal efficiency for TN and TP were in the range of 48-66% and 39-58%, respectively. Additionally, the analysis of the influence of the polishing units did not show a significant improvement (α > 0.05) for any parameter in the wetland systems without a subsequent polishing unit. However, in the wetland systems with a polishing unit of HSSF, a significant improvement (α < 0.05) was found for the effluent's BOD₅, TN and TP concentrations but with no significant contribution in TSS management.     

Tidal reduction and its effects on intertidal hard-substrate communities in the Oosterschelde estuary

Developments of intertidal hard-substrate communities in the Oosterschelde estuary were examined in perpendicular transects between high-water line and low-water line in the period 1982–1992. Prior to the beginning of the Oosterschelde estuary works a typology of communities was established and an overall survey of the estuary was carried out. The communities contain flora (algae) as well as fauna. Due to asphalting of dikes in 1986, much of the surface of several communities has been destroyed. The originally well developed communities with large species-richness have not returned. The small reduction in tidal amplitude due to the construction of the storm-surge barrier had a minor effect on the zonation of communities. In the upper part of the intertidal zone the boundaries of the communities moved 0.5–1.0 m downward in the transects along the dike-slopes. At an average inclination of 18° this means a vertical shift of about 15–30 cm. This reflects the reduction of the tidal amplitude: the high-water line shifted ca 22 cm downward. In a number of places sedimentation has caused a reduction in the number of smaller seaweed species in the lower eulittoral zone. At monitoring locations presence of the original communities is rather unchanged. Rare species like Pelvetia canaliculata, Actinia equina and Gelidium pusillum have been able to maintain quite successfully.     

Characterizing the spatial structures of riparian plant communities in the lower reaches of the Heihe River in China using geostatistical techniques

Geostatistical techniques are used to evaluate spatial characteristics of riparian plant communities that were mapped within a portion of the lower reaches of the Heihe River. The spatial structures of different plant communities were characterized using nugget, range and sill parameters of spherical or exponential model variograms. Model variograms revealed different plant communities with distinctive spatial properties that were quantified effectively by the parameters used in these models. Model variograms were fit to experimental variograms calculated from diameter at breast height and plant cover data collected for three 2,000 m × 5 m, nine 500 m × 5 m, and three 200 m × 2 m transects. The 2,000 m × 5 m transects were oriented perpendicular to the river and the other transects were located in such a way as to sample communities dominated by different plants. Riparian plant communities in the lower reaches of the Heihe River show patterns of patchiness, and the plant communities are mainly dominated by mature Populus euphratica, young P. euphratica, Tamarix chinensis, and Sophora alopecuroides. The maximum model variogram range for all communities was 55 m, suggesting that transects must be at least this long in order to be able to classify them unambiguously into recognizable communities. Experimental variograms were calculated for all plants in each of four mapped plant communities. The results show that the T. chinensis and S. alopecuroides dominated plant communities have distinctively large ranges, and the spatial structures of P. euphratica dominated plant communities show multiscale change. In the 2,000 m × 5 m transects, the spatial structures of riparian plant communities show a distinct change at the scale of 430 m, because this scale also is the scale of vegetation patchiness turnover, and at scales of more than 430 m the spatial structure of the community increases significantly. These findings confirm the potential of using high-resolution remote sensing data and geostatistics for determining the vegetation community structures of riparian plant communities.     

杭州湾及钱塘江河口南岸滨海湿地鸟类群落多样性及其对滩涂围垦的响应

为了解杭州湾及钱塘江河口区域围垦过程中多种人工湿地对于鸟类的作用及在快速的土地利用方式转变过程中鸟类的响应过程,2008年11月至2011年9月,作者对上虞曹娥江口至镇海甬江口沿岸滨海湿地鸟类资源进行调查,共记录鸟类16目52科220种,其中候鸟173种,占总数的78.6％,属于国家Ⅰ、Ⅱ级重点保护野生动物的24种.对研究区域的8种生境的鸟类群落组成、多样性及相似性进行了比较.结果表明,记录物种数较多的生境依次为芦苇水塘(95种,占总数的43.2％)、海涂林地(93种,占总数的42.3％)、自然潮间带和海涂水库(均为78种,各占总数的35.5％),其他生境的物种数均不少于67种(占总数的30.5％以上);从不同鸟类类群的分布看,82.5％的鸻鹬类分布在自然潮间带,69.2％的雁形目鸟类出现在海涂水库,73.4％的雀形目鸟类分布在海涂林地,海涂林地也是大量鹭鸟的繁殖场所;与自然潮间带相似性系数最高的生境依次为围垦滞留区、海涂水库和芦苇水塘,相似性系数分别为0.56、0.34和0.30;从整体上看,海涂林地和海涂水库的鸟类群落G-F指数最高,自然潮间带最低,但水鸟G-F指数最高的生境类型依次为围垦滞留区、海涂水库和自然潮间带.围垦是目前对杭州湾鸟类动态影响最大的人为干扰活动,适度围垦和合理的垦后土地利用方式可能提高整个区域的鸟类多样性水平.为了有效保护杭州湾鸟类多样性尤其是依赖自然潮间带的鸟类多样性,应加强对滩涂资源的保护与可持续利用;在滩涂围垦过程中应尽量保留足够数量和面积的高潮停歇地;同时,加强对围垦滞留区的水位管理,并注重营造适合鸟类栖息的类型多样的围区人工湿地系统.     

Potential of constructed wetland in reducing total nitrogen loading into the Truckee River

A pilot-scale wetland was constructed along Steamboat Creek (SBC) at the Truckee Meadows Water Reclamation Facility (TMWRF), Sparks, Nevada. SBC is a major non-point source of total nitrogen (TN) for the Truckee River. In this study, four (16.2 m²) parallel wetland trains with two different experimental designs were utilized to assess seasonal variations in TN. The experimental designs included: (1) SBC water and SBC sediments (Configuration-1) and (2) TMWRF effluent and SBC sediments (Configuration-2). Over a period of 2 years, the TN in both designs was routinely monitored. TN was reduced by an average of 47% (0.60 mg/l) in Configuration-1 and an average of 24% (0.39 mg/l) in Configuration-2. Nitrogen speciation was an important factor influencing the effectiveness of nitrogen removal within the wetland system. Ammonia-N (NH₃-N) and nitrate plus nitrite nitrogen ((NO₃ + NO₂)-N) were removed more effectively than organic nitrogen. The results obtained from this pilot-scale wetland system suggest that a proposed large-scale constructed wetlands system along SBC would be expected to overall reduce TN loading into the Truckee River from 19 to 30% on an annual basis. This research was jointly funded by the Environmental Protection Agency (EPA) Region 9 and the Nevada Division of Environmental Protection.     

Stress in estuarine communities: Lessons from the highly-impacted Bilbao estuary (Spain)

The highly-impacted Bilbao estuary was studied toquantify the response of estuarine communities tostress. Total heterotrophic biomass, a measure ofsediment infauna, declined sharply from the mouth tothe upper reaches of the estuary. Differentstatistical methods selected the depletion ofdissolved oxygen (DO) at the bottom of the watercolumn as the main correlate with the observedpattern. Biomass size-spectra (BSS) of estuarinecommunities suggested that `unimpacted' sites at themouth of the estuary had a high proportion of biomassin the larger size classes under regular andpredictable environmental conditions. In contrast, inthe impacted middle and inner parts of the estuarybiomass was concentrated in the smaller size classes,indicating a clear effect of stressful environmentalconditions on larger bodied organisms.A progressive increase of DO values has beenforecasted by the local Water Authority after thecompletion of a sewerage plan for the whole estuary,and predictions of water quality criteria were used toestimate community biomass figures following thismanagement. In order to predict the recovery at thelevel of individual species, several bioassays withthe native species Nereis diversicolor andScrobicularia plana were performed. Results obtainedwith the latter, more-sensitive species, suggest thatchemical contamination in sediments from the Bilbaoestuary has the potential to cause deleterious effectson indigenous benthic organisms, which could delayfaunal recovery in some parts of the estuary oncewater-oxic conditions improve.     

长江口浮游甲壳动物空间分布特征

2010年研究了长江口南、北支浮游甲壳动物的空间分布特征。共采集到浮游甲壳动物50种,其中桡足类39种,枝角类11种。种类数南支高于北支;平均密度北支高于南支,南、北支分别为1.7 ind./L和61.8 ind./L。基于群落相似性矩阵的CLUSTER聚类和MDS分析显示,在群落相似性为40%时,长江口区域浮游甲壳动物群落可分为北支组、南支组1和南支组2共3组。3组的优势种有差异。浮游甲壳动物的平均密度变化趋势为北支组（61.8±22.11 ind./L）〉南支组1（3.07±2.06 ind./L）〉南支组2（0.72±0.45 ind./L）。盐度、潮汐和径流量是影响长江口南北支浮游甲壳动物种类组成、密度和空间分布差异的重要环境因素。     

Fish parasite communities in tropical reservoirs along the Perak River, Malaysia

The parasite communities of fish in three reservoirs (Temengor, Kenering and Cenderuh) along the Perak River, as well as in the lower Perak, are compared. A total of 36 species, 51 species, 61 species and 58 species of metazoan parasites from six types of fishes common in all studied locations, were obtained in Temengor, Kenering, Cenderuh Reservoirs, and downstream Perak River, respectively. The various criteria (prevalence, mean intensity, diversity index, similarity index and evenness) of the parasite community were highest at the Cenderuh Reservoir, followed by the downstream river, Kenering, and Temengor Reservoirs. Monogeneans were the most common parasites in all species of fish examined from all study sites. Fish of the same species showed a high degree of similarity of its parasite fauna regardless of study site, but different hosts had a low similarity of their parasite fauna, even within the same study site. This revised version was published online in August 2006 with corrections to the Cover Date.     

长江口北支水域营养盐的季节性变化

于2010年12月—2011年9月,2012年9月—2013年6月按季度采样对长江口北支水域氮、磷营养盐的季度变化规律、形态组成以及环境因子间相互关系进行了分析。结果显示溶解性无机氮存在形态主要是硝酸盐,占90%以上,浓度变化规律为夏秋高于春冬两季;溶解性无机氮、总氮峰值分别为3.99 mg/L及1.70 mg/L,均出现在2011年夏季,该现象与当年洪期长江流域连日降雨有关。长江径流所携带营养盐是导致北支无机氮、总磷浓度变化的主要原因。对理化因子进行相关性分析表明,盐度、pH值是营养盐最主要的限制因子。     

Effects of substratum on the diversity and stability of ammonia-oxidizing communities in a constructed wetland used for wastewater treatment

AIM: To study the relationship between the nature of the substratum and the diversity and stability of the ammonia-oxidizing microbial community in a constructed wetland for the treatment of wastewaters. METHODS AND RESULTS: Samples have been taken the year around from sections of the wetland filled with different substrata. When present, the root zones of the helophyte Phragmites australis were also sampled. The diversity of the ammonia-oxidizing community was established by a coupled PCR-DGGE method based on the 16s rRNA gene. Averaged over the seasons, no large differences in community composition were observed between the different substrata, although the section with zeolite always showed the highest frequencies of bands belonging to ammonia-oxidizing bacteria of the beta-subclass of the Proteobacteria. Only sequences related to the Nitrosospira lineage were detected. Averaged again over the seasons, the section with zeolite was also most constant with respect to the potential ammonia-oxidizing activity. CONCLUSIONS: Although the ammonia-oxidizing communities did not differ significantly between the different sections of the constructed wetland, the characteristics of zeolite were most appropriate to accommodate a stable and active community of ammonia-oxidizing bacteria. The presence of the helophyte had no effect on the diversity and stability of the ammonia-oxidizing community. SIGNIFICANCE AND IMPACT OF THE STUDY: It has been shown that substrata used in constructed wetlands made no distinction between ammonia-oxidizing strains in relation to attachment. However, zeolite had the best performance with respect to activity over the seasons.     

Quantifying the trophic base for benthic secondary production in the Nakdong River estuary of Korea using stable C and N isotopes

The overall dependence of benthic secondary production on the main primary producers at three different habitats in the Nakdong River estuarine system, Korea, was estimated. Inventories of macrobenthic invertebrate biomass were combined with multiple-isotope-mixing models to evaluate the trophic base, comparing Scirpus triqueter-dominated and Phragmites australis-dominated marshes and bare intertidal flat. The feasible contributions of four main food sources, marsh macrophytes, the microphytobenthos, and riverine and marine suspended particulate organic matter (RPOM and MPOM), to the consumer biomasses were calculated using the isotopic mixing model. After weighting the feasible contributions of food sources to each taxon by the consumer biomass, the resultant values were summed for all the consumers at each habitat to quantify the trophic base of the benthic invertebrate community. Dual-isotope-mixing model calculations verified the varying dependence on those potential food sources among the functional feeding groups. In addition, the dependence on each source of the same functional group varied between bare intertidal and salt-marsh habitats, shifting from a dominance of benthic and pelagic microalgal sources on the former habitat to a mixed food source at the latter habitat. The biomasses of the species comprising each functional group differed among habitats and sampling dates, so that each functional group made a different contribution to the whole benthic community and its basal food source. Given the calculation of the overall dependence of macrozoobenthic community on each food source, our results indicate that the microphytobenthic source dominates (nearly half) the trophic base in all the intertidal habitats of different vegetational compositions. Marsh-macrophyte-derived organic matter and RPOM served as considerable subsidies only to salt-marsh food webs, reflecting the use of the mixed food source by salt-marsh-bed consumers. Conversely, the dominance of MPOM in the total food base was equal to that of the microphytobenthos in the bare intertidal ecosystem but increased during spring−summer in the salt-marsh systems. Our results also suggest that the river discharge concentrated during the summer monsoon does not lead to any shift in trophic base for estuarine secondary production.     

长江口北支浮游植物群落结构周年变化特征

2010年10月至2011年9月对长江口北支水域的浮游植物进行周年调查,共采集到183种（包括变种和变型）,隶属于7门60属,其中硅藻门种类最多,有35属137种,占浮游植物总种类数的75%。周年优势种为具槽直链藻、中肋骨条藻、条纹小环藻、两栖颤藻、小伪菱形藻双楔变种、颗粒直链藻和小环藻未定种。本次调查中,季节间浮游植物的丰度差异不显著（P〉0.05）,但各月间浮游植物丰度差异显著（P〈0.05）,全年丰度在2.83×10^3～6.18×10^4cells/L之间,其中6月的丰度最高,1月的丰度最低,全年的平均丰度为1.73×10^4cells/L。Pearson相关性分析显示,浮游植物丰度与硝酸盐浓度显著正相关（P〈0.05）,与氨氮浓度极显著正相关（P〈0.01）,含氮营养盐对浮游植物的影响明显。     

长江口碎波带浮游植物群落结构特征

2009年5月至2010年4月,按月对长江口碎波带浮游植物群落结构和环境因子进行调查。采集到浮游植物64属123种,主要由硅藻、绿藻和蓝藻组成。主要优势种为小环藻,常见种为硅藻门的直链藻（Melosira sp.）、中肋骨条藻（Skeletonema costatum）、膜状舟形藻（Navicula membranacea）,蓝藻门的小颤藻（Oscillatoria tenuis）、小席藻（Phormidium tenue）以及绿藻门的小球藻（Chlorella vulgaris）。浮游植物丰度在8.07×10^4cells/L～1.39×10^6cells/L之间,2009年8月最高,12月最低。浮游植物群落在7—8月份主要由蓝藻组成,其他月份主要由硅藻组成。统计分析细胞丰度与环境因子相关性显示：pH值与绿藻门和蓝藻门的细胞丰度显著负相关（P〈0.05,r〈0）,透明度与绿藻门和蓝藻门的细胞丰度显著正相关（P〈0.05,r〉0）;温度与硅藻门的细胞丰度显著负相关（P〈0.05,r〈0）。     

Changes in the sublittoral hard substrate communities in the Oosterschelde estuary (SW Netherlands), caused by changes in the environmental parameters

In order to assess the effects of the execution of the Delta Project, the sessile sublittoral communities on hard substrates in the Oosterschelde estuary and the environmental parameters were quantitatively investigated from 1985 till 1990. During the construction period of the barrier, three communities were sampled in the photic zone and four in the aphotic zone. The distribution of the communities in the photic zone seemed to be determined by the exposition to water movement and depth, while the communities in the aphotic zone were restricted to geographic areas, with differences in tidal current velocities: the mouth of the estuary, the Hammen, the central part and the Zijpe. Two years after the completion of the enclosure works, the community structure changed rapidly, caused by decreases of tidal current velocities, increases of the amounts of sedimentation, especially of fine sediments, and an increase of the transparency of the water. Changes within the associated vagile animals showed the same tendency as the sessile communities: under less exposed conditions the number of organisms remained the same or increased, while at some locations this increase was nullified by increasing amounts of sedimentation.     

长江口邻近水域浮游动物群落特征及变动趋势

根据2000～2003年长江口邻近海域5月和8月8个航次的调查资料,对长江口浮游动物群落特征的变动趋势进行了研究。结果表明,桡足类、毛颚类和异足类在8月种数明显多于5月。8月暖流势力增强的同时淡水水团势力也增强,不同水团交汇处,浮游动物种类数和多样性指数等值线密集排列,外海暖水带来丰富的种类使该季节的种类数和多样性均明显高于5月。盐度是影响长江口浮游动物群落特征最主要的环境因子。     

Ecology of leaf pack macroinvertebrate communities in streams of the Fraser River Basin, British Columbia

1. To characterise geographic and small scale variation in the structure of macroinvertebrate communities in stream leaf packs, we collected one to three natural leaf pack communities from 119 reference streams in the Fraser River Basin and quantified their variability and correlation with aspects of the stream environment at several scales. We also sampled leaf packs in 19 test streams in the same geographic area exposed to stressors (nine logged, seven farmed, three mined catchments) to evaluate the leaf pack community as a tool for bioassessment. 2. There was substantial variation in the composition of invertebrate communities in leaf packs among reference streams of the Fraser River Basin. Capnia and Zapada (stoneflies), Baetis and Ephemerella (mayflies) and Tvetnia (midge) were the most common taxa found in the leaf packs. There were three types of assemblages identified by non‐metric multidimensional scaling; Capnia, Baetis and Ephemerella communities. 3. Leaf pack communities from the 19 test streams were plotted on a non‐metric multidimensional scaling ordination of the reference communities, and 14 of 19 sites fell outside the 80% confidence ellipse of the reference sites, including eight of nine logged, four of seven farmed and one of three mined catchments. Most of these streams plotted on the ordination near the Ephemerella reference communities. Reference stream communities had a similar number of genera per leaf pack (12.0) and genera per site (18.7) as the test streams (12.6 genera per leaf pack and 18.7 genera per site). Among the test sites, the farmed catchments had higher genera per leaf pack (17.8) and genera per site (21.9) than either the logged (11.5 genera per leaf pack; 19.9 genera per site) or mined (3.4 genera per leaf pack; 7.7 genera per site) catchments. 4. Heterogeneity of leaf pack communities within a site decreased as the number of genera found at the site increased. This was determined by allometric regression of the number of genera found at a site on the maximum number of genera possible, given the average number found per leaf pack. 5. There was a significant relationship between the composition of the leaf pack invertebrate community and stream geography (latitude, longitude, altitude, stream order). Canonical correspondence analysis showed differences among ‘big river’, ‘mountain stream’ and ‘southern’ communities. 6. There was no relationship between the composition of the leaf pack invertebrate community and stream channel and flow characteristics (bank dimensions, flow, slope). There was a significant relationship between the composition of the leaf pack invertebrate community and water quality of the stream (oxygen, nitrogen, phosphorus, conductivity, pH, temperature). ‘Cold, oxygen rich water’ communities were distinguishable from communities in streams with warmer, lower oxygen concentration. ‘High nutrient water’ communities were also distinct from communities in low nutrient streams. There was no relationship between the composition of the leaf pack invertebrate community and the nature of the leaf pack itself (i.e. morphology, decomposition, coniferous needle content). 7. Invertebrate communities in leaf packs show substantial, interpretable variation among reference streams. They are sensitive to human stressors at a landscape scale such as forestry and agriculture. Their diversity and composition varies at different spatial scales in a way that is at least partially explained by the environment of the stream and its catchment area.     

长江口北支大型底栖动物群落周年变化特征

分析了长江口北支滩涂大型底栖动物的群落结构和多样性变化特征。共采集大型底栖动物78种,包括环节动物7种、软体动物23种、节肢动物28种、脊索动物18种、其它两种,全年优势种有8种。密度为0.08 ind/m^2（1月）-1.24 ind/m^2（7月）,生物量为0.006 g/m^2（2月）-0.58 g/m^2（5月）,Margalef丰富度指数（D）为0.82（1月）-3.88（7月）,Pielou均匀度指数（J）为0.60（9月）-0.86（1月）,Shannon-Wiener多样性指数（H＇）为1.59（2月）-2.76（10月）。底栖动物密度与环境因子进行相关性分析显示,北支潮间带的大型底栖动物群落按照盐度、沉积特征等不同可分为3组,盐度和温度是影响底栖动物群落分布的主导因子。