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Evaluation of habitat quality for selected wildlife species associated with island back channels 被引量:1
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作者 James T. Anderson Andrew K. Zadnik +1 位作者 Petra Bohall Wood Kerry Bledsoe 《Open Journal of Ecology》 2013年第4期301-310,共10页
The islands and associated back channels on the Ohio River, USA, are believed to provide critical habitat features for several wildlife species. However, few studies have quantitatively evaluated habitat quality in th... The islands and associated back channels on the Ohio River, USA, are believed to provide critical habitat features for several wildlife species. However, few studies have quantitatively evaluated habitat quality in these areas. Our main objective was to evaluate the habitat quality of back and main channel areas for several species using habitat suitability index (HSI) models. To test the effectiveness of these models, we attempted to relate HSI scores and the variables measured for each model with measures of relative abundance for the model species. The mean belted kingfisher (Ceryle alcyon) HSI was greater on the main than back channel. However, the model failed to predict kingfisher abundance. The mean reproduction component of the great blue heron (Ardea herodias) HSI, total common muskrat (Ondatra zibethicus) HSI, winter cover component of the snapping turtle (Chelydra serpentina) HSI, and brood-rearing component of the wood duck (Aix sponsa) HSI were all greater on the back than main channel, and were positively related with the relative abundance of each species. We found that island back channels provide characteristics not found elsewhere on the Ohio River and warrant conservation as important riparian wildlife habitat. The effectiveness of using HSI models to predict species abundance on the river was mixed. Modifications to several of the models are needed to improve their use on the Ohio River and, likely, other large rivers. 展开更多
关键词 HABITAT Suitability Index ISLAND Back Channel Model Validation OHIO River RIPARIAN WILDLIFE
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Rearing Performance of Juvenile Brown Trout (<i>Salmo trutta</i>) Subjected to Exercise and Dietary Bioprocessed Soybean Meal 被引量:1
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作者 Jill M. Voorhees Michael E. Barnes +1 位作者 Steven R. Chipps Michael L. Brown 《Open Journal of Animal Sciences》 2018年第3期303-328,共26页
This 121-day experiment evaluated the rearing performance of brown trout Salmo trutta fed one of two isonitrogenous and isocaloric diets and reared at velocities of either 2.8 or 16.1 cm/s. Fishmeal was the primary pr... This 121-day experiment evaluated the rearing performance of brown trout Salmo trutta fed one of two isonitrogenous and isocaloric diets and reared at velocities of either 2.8 or 16.1 cm/s. Fishmeal was the primary protein source for the reference diet, and bioprocessed soybean meal replaced approximately 67% of the fishmeal in the experimental diet. At the end of the experiment, there were no significant differences in gain, percent gain, feed conversion rates, or specific growth rates between the dietary treatments. There were also no significant differences in intestinal morphology, splenosomatic, hepatosomatic, and viscerosomatic indices related to diet composition. However, gain, percent gain, feed fed, and specific growth rate were all significantly greater in brown trout reared at the higher velocity. No significant differences in any of the other variables measured were observed between the velocity treatments. There were no significant interactions between diet and velocity in any of the variables. Based on the results of this study, bioprocessed soybean meal can replace at least 67% of the fishmeal in brown trout diets, regardless of the rearing velocities used in this study. However, higher rearing velocities are recommended to maximize juvenile brown trout growth rates. 展开更多
关键词 Brown TROUT SALMO trutta Bioprocessed Soybean MEAL EXERCISE Diet
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Diazinon-Induced Clastogenity and Pathological Changes in Ovaries and Testes of Clarias gariepinus 被引量:1
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作者 Olufunke Eunice Ola-Davies Adekemi Florence Fagbohun +1 位作者 Benjamin Obukowho Emikpe Olanike Kudirat Adeyemo 《Agricultural Sciences》 2015年第1期146-151,共6页
In most tropical developing countries, one of the problems facing aquaculture industry is the pollution of ponds and rivers with pesticides. Chemicals such as diazinon, an organophosphate pesticide, originating from a... In most tropical developing countries, one of the problems facing aquaculture industry is the pollution of ponds and rivers with pesticides. Chemicals such as diazinon, an organophosphate pesticide, originating from agricultural activity enter the aquatic environment through atmospheric deposition, surface run-off or leaching. Pollutants enter the food chain through accumulation in soft bottom sediment and aquatic organisms. However, information on how these pesticides affect inhabiting organisms is often not available. In a triplicate experimental set-up, seventy-two (72) apparently healthy catfish comprising adult and juvenile of both sexes were therefore exposed to a previously determined no effect concentration (0.405 ppm) of diazinon. Another set of fish was exposed to 0.0625 μg sodium arsenite, a known clastogen, which was used as the positive control, while another set of catfish exposed to the culture water alone was the negative control. Adults and juveniles were exposed separately to avoid cannibalism. After 48 hours of exposure, micronuclei induction was determined in subsets of experimental groups, while exposure continued for 28 days. Catfish organs were harvested on days 21 and 28 to determine the effect of long-term exposure to diazinon on histology. Water quality was also monitored before and during exposure in the experimental groups. The result established a significantly high mean micronucleated polychromatic erythrocytes (15.00) in catfish exposed to diazinon suggesting genetic damage (normal is ≤4). The MPE in sodium arsenite exposed fish was 28, while that of the control group was below 4. Effect of sex and age on micronuclei induction was not significant. Histological alteration observed in the ovary and testis was distorted matured cells and extensive testicular degeneration, respectively. The results show that diazinon has clastogenic effect, and may have endocrine disrupting properties because of the histological changes induced in the ovaries and testis. 展开更多
关键词 CATFISH DIAZINON CLASTOGENICITY AQUACULTURE
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FISH ASSEMBLAGE RESPONSES TO DIFFERENT SECONDARY CHANNEL DESIGNS IN THE LOWER MISSISSIPPI RIVER,U.S.A.:A TEMPLATE FOR RIVER RESTORATION
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作者 KAISER Joseph E. SMITH Shannon C.F. +1 位作者 SCHRAMM Jr.,HAROLD L. EGGLETON Michael A. 《水生生物学报》 CAS CSCD 北大核心 2018年第6期1089-1106,共18页
The lower Mississippi River(LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that incl... The lower Mississippi River(LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that includes recreational and commercial fisheries. Due to river training and diversion structures constructed during the past 80 years, the historic characteristics of the LMR have been drastically altered and have likely influenced fishes and fisheries in the system. One common restoration measure used throughout the LMR has been to "notch" wing-dike structures that close secondary(side) river channels. Dike notching allows year-round flows through secondary channels, which enhances habitat diversity and promotes biological productivity at the ecosystem scale. Although notching is presumed good for LMR fishes and other biota, few studies have examined its effects on fish assemblages. In this study, fish assemblages were sampled at seven LMR secondary channels spanning from river kilometer(rkm) 628(Louisiana-Mississippi, U.S.A.) upstream to rkm 1504(Missouri-Kentucky, U.S.A.). Four secondary channels were termed "permanent"(i.e.,with notched dikes) while three secondary channels were termed "temporary"(i.e., without notched dikes).Fishes were sampled by boat-mounted electrofishing conducted during falling and low stages from1995—1997. Fish assemblages differed between permanent and temporary secondary channels, and varied somewhat between falling and low stages. Gizzard shad(Dorosoma cepedianum), threadfin shad(D. petenense), and white bass(Morone chrysops) demonstrated consistent preferences for low-current conditions associated with temporary secondary channels. Conversely, blue catfish(Ictalurus furcatus), flathead catfish(Pylodictis olivaris), and freshwater drum(Aplodinotus grunniens) were more associated with permanent secondary channels. Future restoration strategies in the LMR should consider dike notching and resultant maintenance of permanent secondary channels in selected river reaches. However, temporary secondary channels also contain unique fish species, and also appear to be important sites of riverine primary production. Restoration strategies should consider a balance of both secondary channel types, which should support the greatest biodiversity for the LMR ecosystem. 展开更多
关键词 MISSISSIPPI RIVER SECONDARY channels DIKES Fish ASSEMBLAGES RIVER restoration RIVER rehabilitation
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Fuel and vegetation changes in southwestern, unburned portions of Great Smoky Mountains National Park, USA, 2003-2019
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作者 T.Adam Coates W.Mark Ford 《Journal of Forestry Research》 SCIE CAS CSCD 2022年第5期1459-1470,共12页
Overstory basal area,ericaceous shrub cover(Kalmia latifolia L.and Rhododendron maximum L.),and fuels(i.e.,woody fuel loads and depths and O Horizon thickness) were assessed within Great Smoky Mountains National Park,... Overstory basal area,ericaceous shrub cover(Kalmia latifolia L.and Rhododendron maximum L.),and fuels(i.e.,woody fuel loads and depths and O Horizon thickness) were assessed within Great Smoky Mountains National Park,USA,in 2003-2004.Due to recent wildfire activity within the southern Appalachian Mountain region(including Great Smoky Mountains National Park),the potential spread and expansion of ericaceous shrubs,and the impacts of the hemlock woolly adelgid(Adelges tsugae Annand) on eastern hemlock(Tsuga canadensis(L.) Carrière),these same ecosystem components were again assessed in 2019.Elevation and moisture regime(xeric,intermediate,and mesic) were included in this assessment as potential influential factors.An evaluation of repeated measurements from 40 plots suggested that O Horizon thickness did not change significantly over the 16-year period,but increased as elevation increased,and moisture regime(xeric O Horizon thickness> mesic O Horizon thickness) was a significant,related factor.The sum of 1-,10-,and 100-h fuel loads(fuels less <7.6 cm diameter)increased,whereas woody fuel depth decreased over the16-year period.No significant changes in 1000-h fuel lo ads(>7.6 cm diameter),total woody fuel loads,ericaceous shrub cover,total basal area,or live T.canadensis basal area were observed.Live T.canadensis basal area decreased with increasing elevation.Dead,standing T.canadensis basal area increased from 2003-2019,and that increase was most pronounced as elevation increased on xeric and intermediate sites.Overall,we found that:1.hypothesized increases in total woody fuel loads and ericaceous shrub cover were not present;and 2.elevation and moisture regime were most related to observed changes in vegetation and fuel condition. 展开更多
关键词 Eastern hemlock Hemlock woolly adelgid Mountain laurel RHODODENDRON
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Effects of historic wildfire and prescribed fire on site occupancy of bats in Shenandoah National Park,Virginia,USA
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作者 Lauren V.Austin Alexander Silvis +1 位作者 W.Mark Ford Karen E.Powers 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第4期1255-1270,共16页
Given the likelihood of regional extirpation of several once-common bat species in eastern North America from white-nose syndrome,it is critical that the impacts of forest management activities,such as prescribed fire... Given the likelihood of regional extirpation of several once-common bat species in eastern North America from white-nose syndrome,it is critical that the impacts of forest management activities,such as prescribed fire,are known in order to minimize potentially additive negative effects on bat populations.Historic wildfires may offer a suitable surrogate to assess long-term burn impacts on bats for planning,implementing and assessing burn programs.To examine the effects of historic fire on bats,we sampled bat activities at 24 transect locations in burned and unburned forest stands in the central Appalachian Mountains of Shenandoah National Park(SNP),Virginia,USA.There was limited evidence of positive fire effects over time on hoary bats(Lasiurus cinereus Beauvois)and big brown bats(Eptesicus fuscus Beauvois)occupancy.Overall,there were few or mostly equivocal relationships of bat occupancy relative to burn conditions or time since fire in SNP across species using a false-positive occupancy approach.Our results suggest that fire does not strongly affect bat site occupancy short-or long-term in the central Appalachians. 展开更多
关键词 Appalachian mountains Bats False-positive occupancy Prescribed fire WILDFIRE
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Comparison of Geographically Weighted Regression of Benthic Substrate Modeling Accuracy on Large and Small Wadeable Streams
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作者 Ken R. Sheehan Stuart A. Welsh 《Journal of Geographic Information System》 2021年第2期194-209,共16页
Aquatic habitat assessments encompass large and small wadeable streams which vary from many meters wide to ephemeral. Differences in stream sizes within or across watersheds, however, may lead to incompatibility of da... Aquatic habitat assessments encompass large and small wadeable streams which vary from many meters wide to ephemeral. Differences in stream sizes within or across watersheds, however, may lead to incompatibility of data at varying spatial scales. Specifically, issues caused by moving between scales on large and small streams are not typically addressed by many forms of statistical analysis, making the comparison of large (>30 m wetted width) and small stream (<10 m wetted width) habitat assessments difficult. Geographically weighted regression (GWR) may provide avenues for efficiency and needed insight into stream habitat data by addressing issues caused by moving between scales. This study examined the ability of GWR to consistently model stream substrate on both large and small wadeable streams at an equivalent resolution. We performed GWR on two groups of 60 randomly selected substrate patches from large and small streams and used depth measurements to model substrate. Our large and small stream substrate models responded equally well to GWR. Results showed no statistically significant difference between GWR R<sup>2 </sup>values of large and small stream streams. Results also provided a much needed method for comparison of large and small wadeable streams. Our results have merit for aquatic resource managers, because they demonstrate ability to spatially model and compare substrate on large and small streams. Using depth to guide substrate modeling by geographically weighted regression has a variety of applications which may help manage, monitor stream health, and interpret substrate change over time. 展开更多
关键词 Stream Habitat Modeling Geographically Weighted Regression Spatial Scale Habitat Interpolation Geographic Information System
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Availability and Timing of Fathead Minnow Supplementation Influence Largemouth Bass Survival and Production in Rearing Ponds
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作者 Matthew J. Ward Steven R. Chipps 《Open Journal of Animal Sciences》 2020年第3期337-345,共9页
Adjustments to rearing practices should be justified with increases in production, stocking success, or angler satisfaction. Largemouth bass (<span style="white-space:nowrap;"><i></span>Mic... Adjustments to rearing practices should be justified with increases in production, stocking success, or angler satisfaction. Largemouth bass (<span style="white-space:nowrap;"><i></span>Micropterus salmoides<span style="white-space:nowrap;"></i></span>) production was assessed between hatchery ponds where fish were restricted to an invertebrate diet or received supplemental fathead minnow (<span style="white-space:nowrap;"><i></span>Pimephales promelas<span style="white-space:nowrap;"></i></span>) forage during 2015. At harvest, age-0 bass yield was 4.5 times greater and average fish length was 38 mm longer, in the pond that received fathead minnow. In 2016, a second study evaluated the timing of minnow supplementation that included earlier stockings of small fathead minnow (<30 mm) compared to delayed supplementation with larger (>30 mm) minnows. With earlier supplementation, bass yield was 2.3 times greater and fish averaged 14 mm longer at harvest. Bass survival was approximately 38% higher during 2015 when supplementation occurred and 25% higher during 2016 when minnow supplementation began earlier. Our findings show invertebrate forage was probably limiting bass production in hatchery ponds and supplementing with appropriately-sized fathead minnows increased age-0, largemouth bass production. 展开更多
关键词 Largemouth Bass Culture Pond-Rearing Fathead Minnow Stocking
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影响鱼类分布的生态水文因子建模及分析(英文) 被引量:2
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作者 张天蛟 刘刚 +2 位作者 Thomas A.Worthington Shannon K.Brewer Dan E.Storm 《农业工程学报》 EI CAS CSCD 北大核心 2015年第S2期237-245,共9页
人类活动干扰下河流自然水势改变,导致鱼类栖息地环境变化。为准确分析影响鱼类分布的生态水文环境,该文以美国阿肯色河流域的国家级濒危小型鱼类:产漂流性卵鲤鱼(Arkansas River Shiner,Notropis girardi,ARS)为例,根据其繁殖期特有的... 人类活动干扰下河流自然水势改变,导致鱼类栖息地环境变化。为准确分析影响鱼类分布的生态水文环境,该文以美国阿肯色河流域的国家级濒危小型鱼类:产漂流性卵鲤鱼(Arkansas River Shiner,Notropis girardi,ARS)为例,根据其繁殖期特有的水文条件需求,选取流域40个水文站点的日径流数据,分别计算历史时期(1950-1962年)和当前时期(1990-2010年)的3个繁殖期生态水文因子:高流量,较高流量历时及断流历时。每个生态水文因子分别结合其他25个环境因子,基于最大熵理论(Max Ent)构建物种分布模型。运用经典受试者工作曲线(receiver operating characteristic,ROC)及Parolo等提出的模型转移前后预测结果的Spearman’s rho相关系数,评价模型的自适应性(model fit)和转移能力(transferability)。3个模型在两个时期的ROC曲线与横坐标围成的面积均大于0.95,模型转移前后预测结果的Spearman’s rho相关系数均大于0.6。研究分析表明,模型具有较好的自适应性及转移性。3个生态水文因子中,高流量对模型的贡献率最大,对该种鱼类在两个时期的潜在分布影响最显著。不同的历史时期,物种的潜在适生概率随同一生态水文因子的变化呈现出了不一致的变化趋势。3个模型均预测出ARS的潜在生境有相同的空间变化趋势。该研究结果能够为中国保护河流生态系统与濒危鱼类提供借鉴经验。 展开更多
关键词 模型 生态系统 最大熵(MaxEnt)模型 生态水文因子 繁殖期 产漂流性卵
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Accuracy of Stream Habitat Interpolations Across Spatial Scales 被引量:1
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作者 Kenneth R. Sheehan Stuart A. Welsh 《Journal of Geographic Information System》 2013年第6期602-612,共11页
Stream habitat data are often collected across spatial scales because relationships among habitat, species occurrence, and management plans are linked at multiple spatial scales. Unfortunately, scale is often a factor... Stream habitat data are often collected across spatial scales because relationships among habitat, species occurrence, and management plans are linked at multiple spatial scales. Unfortunately, scale is often a factor limiting insight gained from spatial analysis of stream habitat data. Considerable cost is often expended to collect data at several spatial scales to provide accurate evaluation of spatial relationships in streams. To address utility of single scale set of stream habitat data used at varying scales, we examined the influence that data scaling had on accuracy of natural neighbor predictions of depth, flow, and benthic substrate. To achieve this goal, we measured two streams at gridded resolution of 0.33 × 0.33 meter cell size over a combined area of 934 m2 to create a baseline for natural neighbor interpolated maps at 12 incremental scales ranging from a raster cell size of 0.11 m2 to 16 m2. Analysis of predictive maps showed a logarithmic linear decay pattern in RMSE values in interpolation accuracy for variables as resolution of data used to interpolate study areas became coarser. Proportional accuracy of interpolated models (r2) decreased, but it was maintained up to 78% as interpolation scale moved from 0.11 m2 to 16 m2. Results indicated that accuracy retention was suitable for assessment and management purposes at various scales different from the data collection scale. Our study is relevant to spatial modeling, fish habitat assessment, and stream habitat management because it highlights the potential of using a single dataset to fulfill analysis needs rather than investing considerable cost to develop several scaled 展开更多
关键词 Natural NEIGHBOR Interpolation RESIDUALS Ordinary Least SQUARES STREAM Modeling HABITAT BENTHIC Substrate
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Sedimentation in Mountain Streams: A Review of Methods of Measurement 被引量:1
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作者 Lara B. Hedrick James T. Anderson +1 位作者 Stuart A. Welsh Lian-Shin Lin 《Natural Resources》 2013年第1期92-104,共13页
The goal of this review paper is to provide a list of methods and devices used to measure sediment accumulation in wadeable streams dominated by cobble and gravel substrate. Quantitative measures of stream sedimentati... The goal of this review paper is to provide a list of methods and devices used to measure sediment accumulation in wadeable streams dominated by cobble and gravel substrate. Quantitative measures of stream sedimentation are useful to monitor and study anthropogenic impacts on stream biota, and stream sedimentation is measurable with multiple sampling methods. Evaluation of sedimentation can be made by measuring the concentration of suspended sediment, or turbidity, and by determining the amount of deposited sediment, or sedimentation on the streambed. Measurements of deposited sediments are more time consuming and labor intensive than measurements of suspended sediments. Traditional techniques for characterizing sediment composition in streams include core sampling, the shovel method, visual estimation along transects, and sediment traps. This paper provides a comprehensive review of methodology, devices that can be used, and techniques for processing and analyzing samples collected to aid researchers in choosing study design and equipment. 展开更多
关键词 MOUNTAIN SAMPLERS SEDIMENT STREAMS
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Predicting intensity of white-tailed deer herbivory in the Central Appalachian Mountains
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作者 Andrew B.Kniowski W.Mark Ford 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第3期830-839,共10页
In eastern North America, white-tailed deer(Odocoileus virginianus) can have profound influences on forest biodiversity and forest successional processes.Moderate to high deer populations in the central Appalachians h... In eastern North America, white-tailed deer(Odocoileus virginianus) can have profound influences on forest biodiversity and forest successional processes.Moderate to high deer populations in the central Appalachians have resulted in lower forest biodiversity.Legacy effects in some areas persist even following deer population reductions or declines. This has prompted managers to consider deer population management goals in light of policies designed to support conservation of biodiversity and forest regeneration while continuing to support ample recreational hunting opportunities. However,despite known relationships between herbivory intensity and biodiversity impact, little information exists on the predictability of herbivory intensity across the varied and spatially diverse habitat conditions of the central Appalachians. We examined the predictability of browsing rates across central Appalachian landscapes at four environmental scales: vegetative community characteristics, physical environment, habitat configuration, and local human and deer population demographics. In an information-theoretic approach, we found that a model fitting the number of stems browsed relative to local vegetation characteristics received most(62%) of the overall support of all tested models assessing herbivory impact. Our data suggest that deer herbivory responded most predictably to differences in vegetation quantity and type. No other spatial factors or demographic factors consistently affected browsing intensity. Because herbivory, vegetation communities, and productivity vary spatially, we suggest that effective broad-scale herbivory impact assessment should include spatially-balanced vegetation monitoring that accounts for regional differences in deer forage preference.Effective monitoring is necessary to avoid biodiversity impacts and deleterious changes in vegetation community composition that are difficult to reverse and/or may not be detected using traditional deer-density based management goals. 展开更多
关键词 BIODIVERSITY Central Appalachian Mountains HERBIVORY Odocoileus virginianus Predicting browsing intensity White-tailed deer
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Responses of early-successional songbirds to a two-stage shelterwood harvest for oak forest regeneration
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作者 Eric L.Margenau Yong Wang +1 位作者 Callie J.Schweitzer BrANDie K.Stringer 《Avian Research》 CSCD 2018年第3期253-263,共11页
Background: The early stage of forest succession following disturbance is characterized by a shift in songbird composition as well as increased avian richness due to increased herbaceous growth in the forest understor... Background: The early stage of forest succession following disturbance is characterized by a shift in songbird composition as well as increased avian richness due to increased herbaceous growth in the forest understory. However, regeneration of woody species eventually outcompetes the herbaceous understory, subsequently shifting vegetation communities and decreasing availability of vital foraging and nesting cover for disturbance-dependent birds, ultimately resulting in their displacement. These early stages following forest disturbance, which are declining throughout the eastern United States, are ephemeral in nature and birds depend on such disturbances for nesting and other purposes throughout their lives.Methods: We investigated the use of a two-stage shelterwood method to manage long-term persistence of seven early successional songbirds over a 13-year period in an upland hardwood forest within the southern end of the midCumberland Plateau in the eastern United States.Results: Canopy and midstory gaps created after initial harvest were quickly exploited by tree growth and canopy cover returned to these areas, accelerating the displacement of early-successional species. Woody stem densities increased substantially following stage two harvest as advanced tree regeneration combined with the re-opening of the overstory layer increased resource competition for early-successional plants in the understory. Carolina Wren(Thryothorus ludovicianus), Eastern Towhee(Pipilo erythrophthalmus), Indigo Bunting(Passerina cyanea), and Yellowbreasted Chat(Icteria virens) were characterized by immediate increases following initial harvest in 2001; while the American Goldfinch(Spinus tristis), Prairie Warbler(Setophaga discolor), and White-eyed Vireo(Vireo griseus) did not show an immediate response. Stage two harvest in 2011 rejuvenated vegetation which benefitted focal species, with six of seven species showing increases in densities between 2010 and 2012.Conclusion: The two-stage shelterwood method created conditions advantageous to early-successional birds by helping to re-establish understory vegetation through periodic disturbance to the canopy layer. This method provides evidence that early-successional species can be managed long-term(> 15 years) while using relatively small spatial disturbance through the two-stage shelterwood method. 展开更多
关键词 Early-successional forests Mid-Cumberland Plateau SILVICULTURE SHELTERWOOD SONGBIRD community
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Seasonal comparison of aquatic macroinvertebrate assemblages in a flooded coastal freshwater marsh
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作者 Sung-Ryong Kang Sammy L. King 《Open Journal of Ecology》 2013年第2期94-101,共8页
Marsh flooding and drying may be important factors affecting aquatic macroinvertebrate density and distribution in coastal freshwater marshes. Limited availability of water as a result of drying in emergent marsh may ... Marsh flooding and drying may be important factors affecting aquatic macroinvertebrate density and distribution in coastal freshwater marshes. Limited availability of water as a result of drying in emergent marsh may decrease density, taxonomic diversity, and taxa richness. The principal objectives of this study are to characterize the seasonal aquatic macroinvertebrate assemblage in a freshwater emergent marsh and compare aquatic macroinvertebrate species composition, density, and taxonomic diversity to that of freshwater marsh ponds. We hypothesize that 1) freshwater emergent marsh has lower seasonal density and taxonomic diversity compared to that of freshwater marsh ponds;and 2) freshwater emergent marsh has lower taxa richness than freshwater marsh ponds. Seasonal aquatic macroinvertebrate density in freshwater emergent marsh ranged from 0 organisms/m2 (summer 2009) to 91.1 ± 20.53 organisms/m2 (mean ± SE;spring 2009). Density in spring was higher than in all other seasons. Taxonomic diversity did not differ and there were no unique species in the freshwater emergent marsh. Our data only partially support our first hypothesis as aquatic macroinvertebrate density and taxonomic diversity between freshwater emergent marsh and ponds did not differ in spring, fall, and winter but ponds supported higher macroinvertebrate densities than freshwater emergent marsh during summer. However, our data did not support our second hypothesis as taxa richness between freshwater emergent marsh and ponds did not statistically differ. 展开更多
关键词 FRESHWATER Emergent MARSH FRESHWATER POND AQUATIC MACROINVERTEBRATE
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Chronic Exposure to No-Effect Concentration of Diazinon Induced Histological Lesions in Organs of <i>Clarias</i><i>gariepinus</i>
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作者 Adekemi Florence Fagbohun Olufunke Eunice Ola-Davies +2 位作者 Benjamin Obukowho Emikpe Oluwafemi Obagbemiro Olanike Kudirat Adeyemo 《Agricultural Sciences》 2020年第7期627-637,共11页
In all parts of the world pesticides have been found in the aquatic ecosystem and scientific evidence has also shown that they can enter the food chain. Diazinon is an organophosphate pesticide, widely used in agricul... In all parts of the world pesticides have been found in the aquatic ecosystem and scientific evidence has also shown that they can enter the food chain. Diazinon is an organophosphate pesticide, widely used in agriculture to control a wide variety of suckling and leaf eating insects and recently in fish culture to suppress some parasitic diseases;nevertheless, there is little study on its adverse effect on fish. In this study, seventy-two (72) apparently healthy catfish comprising adult and juvenile of both sexes were used to set up triplicate experimental groups of those exposed to culture water alone (control group), fish exposed to pre-determined no-effect concentration (0.405 ppm) of Diazinon (test group). The fish were exposed for 28 days and fish were sacrificed and organs harvested on days 21 and 28 to determine the effect of long-term exposure to diazinon on organ histology. Histological changes observed in diazinon-exposed catfish were hyperplasia and fusion of the gill epithelium, hyperplasia of mucoid producing cells and aggregation of melanin pigment in the skin. Histological lesions were also seen observed in other organs, including severe diffuse cellular swelling and fatty degeneration of the liver, interstitial congestion of the kidney, carbon deposit on the wall of the heart and multifocal haemorrhage. The water quality of the control was not significantly different from that of the test group throughout the experiment. The lesions detected in cells, tissue, or organs represent an integration of cumulative effects of physiological and biochemical stressors. The histological alterations observed in vital organ of fish show that exposure to “no-effect” concentration of diazinon induced structural damage in fish organs and are likely to affect the functionality of the organs. For example, the adverse effect on the gill might disrupt its feeding and oxygen uptake. 展开更多
关键词 DIAZINON HISTOPATHOLOGY Clarias gariepinus
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Population Characteristics of Ozark Bass (<i>Ambloplites constellatus</i>) in the Upper White River Basin of Northern Arkansas
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作者 Ashley Rodman Kristofor R. Brye +1 位作者 Daniel Magoulick Stan Todd 《Natural Resources》 2019年第5期121-138,共18页
Ozark Bass (Ambloplites constellatus) is an understudied, endemic fish species in the Upper White River Basin of northern Arkansas. This study was part of an effort by fisheries managers to gather baseline data about ... Ozark Bass (Ambloplites constellatus) is an understudied, endemic fish species in the Upper White River Basin of northern Arkansas. This study was part of an effort by fisheries managers to gather baseline data about the Ozark Bass to aid in understanding population dynamics and contribute to the limited data available for use in determining the efficacy of harvest regulations. Select population characteristics of Ozark Bass in two northern Arkansas streams were determined, population characteristics of Ozark Bass were compared to Shadow Bass (Ambloplites ariommus) and Rock Bass (Ambloplites rupestris) data collected from previous studies in southern Missouri, and relative condition, length-at-age, and annual survival of Ozark Bass were compared between sample streams. Sampling occurred in Crooked Creek and the Buffalo River during summer 2013 via boat electroshocking. Length and weight data were recorded for all Ozark Bass collected, and fish ages were determined through selective otolith retrieval and age-length keys. Ozark Bass in Crooked Creek had greater relative condition than Ozark Bass in Buffalo River (P P > 0.05) between sexes for fish collected from only the Buffalo River. Ozark Bass mean annual survival was similar between Crooked Creek (55% ± 5% as 95% confidence interval (CI)) and the Buffalo River (50% ± 7% CI) for fish age 2 to 9. Calculated Ozark Bass lengths-at-age for fish from both streams were comparable to the Von Bertalanffy growth estimates, except the Buffalo River age 7 category where there was only one observation. The relationship between Ozark Bass age and length differed between sampled streams, and variability in growth rates and length-at-age were observed among Ambloplites species. Results of this study contribute to the understanding of the population dynamics of the Ozark Bass that will lead to improved fisheries management. 展开更多
关键词 ENDEMIC Fish Measurements FISHING Regulations Ozarks
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Fish diversity reduction and assemblage structure homogenization in lakes:A case study on unselective fishing in China
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作者 Han Liu Yushun Chen +7 位作者 Rodolphe E.Gozlan Xiao Qu Wentong Xia Fei Cheng Lizhu Wang Craig P.Paukert Julian D.Olden Songguang Xie 《Water Biology and Security》 2022年第3期43-50,共8页
Unselective fishing involves activities that target the entire assemblage rather than specific fish species,size classes,or trophic levels.This common fishing approach has been in practice for decades in inland waters... Unselective fishing involves activities that target the entire assemblage rather than specific fish species,size classes,or trophic levels.This common fishing approach has been in practice for decades in inland waters in China but its implications for biodiversity remain unclear.We addressed this issue by studying fish assemblages in freshwater lakes(five fishing lakes,one reference lake,and a total of 51 sampling sites)between pre-and postfishing time-periods in Eastern China during 2017–2019.The effects of lake,fishing period,and their interactions on fish abundance,biomass,and diversity indices were assessed.Multivariate analysis was conducted to test for differences in fish assemblages among lakes and between fishing periods.After the implementation of fishing activities,significant reductions in fish species richness,abundance,biomass,and all three life-history strategies(opportunistic,equilibrium,and periodic)were observed in fishing lakes,whereas opposite trends were observed in the reference lake.Compositional similarity of fish assemblages among fishing lakes increased over the threeyear monitoring period.Our results suggest that unselective fishing reduces fish diversity and homogenizes fish assemblage structure in lakes.These findings have important implications for protecting both biodiversity and fisheries in inland waters in China and are applicable to other countries or regions that rely on fish as a major food source. 展开更多
关键词 Biodiversity conservation Human stressors Inland fisheries Over exploitation SUSTAINABILITY Beta diversity
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淡水珍珠贝寿命差异的研究:检验动物长寿机制的样板种类
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作者 Valery Ziuganov Eduardo San Miguel +9 位作者 Richard J.Neves Angeles Longa CarlosFernández Rafaela Amaro Victor Beletsky Ekaterina Popkovitch Sviatoslav Kaliuzhin Torbjrn Johnson 樊恩源 张晓琴 《AMBIO-人类环境杂志》 2000年第2期101-105,124,共5页
世界上已知有十多种动物的最大寿命(Amax)可超过100年,淡水珍珠贝(Margaritifera margaritifera)即是其中的一种。这种动物寿命较长者可达到100~200年,寿命的长短与其生活地的环境条件及所处纬度有关。淡水珍珠贝南方种群与北极地区种... 世界上已知有十多种动物的最大寿命(Amax)可超过100年,淡水珍珠贝(Margaritifera margaritifera)即是其中的一种。这种动物寿命较长者可达到100~200年,寿命的长短与其生活地的环境条件及所处纬度有关。淡水珍珠贝南方种群与北极地区种群相比,其寿命差异可以达3~7倍。一些南方种群的最大寿命为28~40年,而在北极地区则可达到114~190年。用进化和生态学的观点来看,北极地区珍珠贝长寿的原因可能是因为这些地区性种群已适应了当地恶劣、多变的气候及水文条件,寒冷气候条件下较低的代谢率及生长过程中较低的能量消耗均对长寿产生了积极的影响。为使损坏的贝壳或机体组织得以修复或自愈,这类物种通常能很快地将其代谢率水平增加至130倍。通过对这类物种进行生理学的研究,相信在理解长寿和延迟衰老的机理方面能有极大的收获。 展开更多
关键词 淡水珍珠贝 寿命差异 长寿机制 环境 遗传
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Bright spots for inland fish and fisheries to guide future hydropower development
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作者 William M.Twardek Ian G.Cowx +17 位作者 Nicolas W.R.Lapointe Craig Paukert T.Douglas Beard Elena M.Bennett David Browne Andrew K.Carlson Keith D.Clarke Zeb Hogan Kai Lorenzen Abigail J.Lynch Peter B.McIntyre Paulo Pompeu Mark Rogers Alexis Sakas William W.Taylor Taylor D.Ward Zeenatul Basher Steven J.Cooke 《Water Biology and Security》 2022年第1期81-99,共19页
Hydropower production is one of the greatest threats to fluvial ecosystems and freshwater biodiversity.Now that we have entered the Anthropocene,there is an opportunity to reflect on what might constitute a‘sustaina... Hydropower production is one of the greatest threats to fluvial ecosystems and freshwater biodiversity.Now that we have entered the Anthropocene,there is an opportunity to reflect on what might constitute a‘sustainable’Anthropocene in the context of hydropower and riverine fish populations.Considering elements of existing practices that promote favorable social-ecological outcomes(i.e.,‘bright spots’)is timely given that there are plans to expand hydropower capacity in previously undammed rivers,intensify dam development in some of the world's largest river systems,and re-license existing facilities.We approach this from a pragmatic perspective:for the foreseeable future,hydropower will likely remain an important source of renewable electricity.To offer support for moving toward a more‘sustainable’Anthropocene,we provide syntheses of best practices during the siting,design,construction,operation,and compensation phases of hydropower development to minimize impacts on inland fish.For each phase,we offer positive examples(or what might be considered‘bright spots’)pertaining to some of the approaches described within our syntheses,acknowledging that these projects may not be viewed as without ecological and(or)societal detriment by all stakeholders.Our findings underscore the importance of protecting critical habitat and free-flowing river reaches through careful site selection and basinscale planning,infrastructure designs that minimize reservoir effects and facilitate safe passage of fish,construction of hydropower plants using best practices that minimize long-term damage,operating guidelines that mimic natural flow conditions,and compensation that is lasting,effective,inclusive,and locally relevant.Learning from these‘bright spots’may require engagement of diverse stakeholders,professionals,and governments at scales that extend well beyond a given site,river,or even basin.Indeed,environmental planning that integrates hydropower development into broader discussions of conserving regional biodiversity and ecosystem services will be of utmost importance. 展开更多
关键词 Migration DAMS SALMON Hydroelectric Flow Socioecological Fish passage Barriers ECOSYSTEMS
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Approaching the upper boundary of driver-response relationships:identifying factors using a novel framework integrating quantile regression with interpretable machine learning
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作者 Zhongyao Liang Yaoyang Xu +4 位作者 Gang Zhao Wentao Lu Zhenghui Fu Shuhang Wang Tyler Wagner 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2023年第6期153-163,共11页
The identification of factors that may be forcing ecological observations to approach the upper boundary provides insight into potential mechanisms affecting driver-response relationships,and can help inform ecosystem... The identification of factors that may be forcing ecological observations to approach the upper boundary provides insight into potential mechanisms affecting driver-response relationships,and can help inform ecosystem management,but has rarely been explored.In this study,we propose a novel framework integrating quantile regression with interpretable machine learning.In the first stage of the framework,we estimate the upper boundary of a driver-response relationship using quantile regression.Next,we calculate“potentials”of the response variable depending on the driver,which are defined as vertical distances from the estimated upper boundary of the relationship to observations in the driver-response variable scatter plot.Finally,we identify key factors impacting the potential using a machine learning model.We illustrate the necessary steps to implement the framework using the total phosphorus(TP)-Chlorophyll a(CHL)relationship in lakes across the continental US.We found that the nitrogen to phosphorus ratio(N:P),annual average precipitation,total nitrogen(TN),and summer average air temperature were key factors impacting the potential of CHL depending on TP.We further revealed important implications of our findings for lake eutrophication management.The important role of N:P and TN on the potential highlights the co-limitation of phosphorus and nitrogen and indicates the need for dual nutrient criteria.Future wetter and/or warmer climate scenarios can decrease the potential which may reduce the efficacy of lake eutrophication management.The novel framework advances the application of quantile regression to identify factors driving observations to approach the upper boundary of driver-response relationships. 展开更多
关键词 Driver-response Upper boundary of relationship Interpretable machine learning Quantile regression Total phosphorus Chlorophyll a
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