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June-Wells M, Gallagher F, Hart B, Malik V, Bugbee G. 2016. The relative influences of fine and landscape scale factors on the structure of lentic plant assemblages. Lake Reserv Manage. 32:116–131.The process of plant community assembly has long been a topic of debate among ecologists. Aquatic plant assemblages and their structure may be the result of a series of abiotic and biotic filters that include transport (i.e., physical movement of species), water chemistry, sediment chemistry, basin structure, and competitive interactions. The influences of transport and water chemistry have been well investigated, but many questions persist about the interrelationships among water and sediment variables, including their combined influences on the structure of the aquatic plant assemblage. To understand how these abiotic conditions interact, we sampled 750 points in 30 lakes. Using these data, a split canonical correspondence design was used to evaluate the relative influences of regional and fine-scale c...

Our analysis of 156 lakes and 5 nonnative aquatic macrophyte species suggest that 4 water chemistry variables can be used to assess the risk associated with species invasion in Connecticut lakes. Our analysis showed that water chemistry and longitude explained a significant amount of the total data variance (33%). Additionally, individual species logistic regressions suggest that these species’ distributions were determined by the specific conductance and pH of the water body. Lakes were then placed into one of the following groups: (1) Cabomba caroliniana/ Myriophyllum heterophyllum (CM), (2) Myriophyllum spicatum/Najas minor/Potamogeton crispus (MNP), (3) Mixed (Mixed), or (4) No Invasive (NI). Multivariate analysis of variance suggests that water chemistry of the groups CM and MNP differed significantly (p < 0.001), and the variables that contributed to this difference were specific conductance (F = 22.16), alkalinity (F = 19.40), and pH (F = 18.61). The Mixed and No Invasive groups were not s...

The aquarium trade has been shown to be a source for introductions of nonnative aquatic macrophyte species. Improvements are needed in identification, labeling, and retailer awareness of banned aquatic plants. In the state of Connecticut, United States, 20 nonnative macrophytes are banned from sale by state statute. At least 13 of these species are already established in the state's lakes, while the remainder are either present in near-shore wetlands or absent but thought to be capable of naturalizing. We documented the sale of banned plants in the Connecticut aquarium trade by visiting 23 retailers in 2008 and 47 retailers in 2010. Plants that resembled Connecticut's banned species were purchased and identified using standard morphological techniques. In 2010, we also employed DNA sequencing to aid in plant identification. We found that nearly 30% of stores sold banned aquatic plants including Cabomba caroliniana, Egeria densa, Myriophyllum aquaticum, and Myriophyllum heterophyllum. Cabomba caro...

SUMMARY 1. The structure of biological communities reflects the influence of both local environmental conditions and processes such as dispersal that create patterns in species’ distribution across a region. 2. We extend explicit tests of the relative importance of local environmental conditions and regional spatial processes to aquatic plants, a group traditionally thought to be little limited by dispersal. We used partial canonical correspondence analysis and partial Mantel tests to analyse data from 98 lakes and ponds across Connecticut (northeastern United States). 3. We found that aquatic plant community structure reflects the influence of local conditions (pH, conductivity, water clarity, lake area, maximum depth) as well as regional processes. 4. Only 27% of variation in a presence ⁄ absence matrix was explained by environmental conditions and spatial processes such as dispersal. Of the total explained, 45% was related to environmental conditions and 40% to spatial processes. 5. Jaccard similarity declined with Euclidean distance between lakes, even after accounting for the increasing difference in environmental conditions, suggesting that dispersal limitation may influence community composition in the region. 6. The distribution of distances among lakes where species occurred was associated with dispersal-related functional traits, providing additional evidence that dispersal ability varies among species in ways that affect community composition. 7. Although environmental and spatial variables explained a significant amount of variation in community structure, a substantial amount of stochasticity also affects these communities, probably associated with unpredictable colonisation and persistence of the plants.

Invasive plants alter community structure, threatening ecosystem function and biodiversity, but little information is available on whether invasive species richness responds to environmental conditions in the same way that richness of native plants does. We surveyed submerged and floating-leaved plants in 99 Connecticut (northeast USA) lakes and ponds, collecting quantitative data on abundance and frequency. We used multiple linear and logistic regression to determine which environmental conditions were correlated with species richness of invasive and native plants. Independent variables included lake area, maximum depth, pH, alkalinity, conductivity, phosphorus concentration, productivity, and dominance (the proportional abundance of the most abundant and frequently found species), plus two estimates of human activity. Species richness of both native and invasive richness was correlated with alkalinity and human activity. Native richness also increased with water clarity, lake area, and productivity; invasive species richness also rose with pH. We found no evidence that richness of one group affected richness of the other. We also investigated patterns of dominance and found that native plants were as likely to become dominant as invasive species. Dominance occurred overwhelmingly in shallow lakes with high productivity. Resume´ : Les plantes envahissantes modifient la structure des communautes en menacant les fonctions des ecosystemes et leur biodiversite ´, mais on connaoˆt peu de chose asavoir si la richesse en especes envahissantes reagit aux conditions du milieu de la meme facon que la richesse en plantes indigenes. Les auteurs ont suivi les plantes submergees et afeuilles flottantes dans 99 lacs et etang du nord-est des Etats-Unis, en reunissant les donnees d'abondance et de frequence. Ils ont utilisela regression lineaire multiple et logistique pour determiner quelles conditions environnementales montrent une cor- relation avec les richesses en especes des plantes envahissantes et indigenes. Les variables independantes comprennent la surface des lacs, la profondeur maximum, le pH, l'alcalinite ´, la conductivite ´, la teneur en phosphore, la productiviteet la dominance (l'abondance proportionnelle des especes les plus frequentes et les plus abondantes), ainsi que deux valeurs es- timees pour l'activitehumaine. La richesse en especes indigenes aussi bien qu'en especes envahissantes montre une corre ´- lation avec l'alcaliniteet l'activitehumaine. La richesse en especes indigenes augmente egalement avec la clartede l'eau, la surface du lac et la productivite ´; la richesse en especes adventices augmente aussi avec le pH. On ne percoit aucune preuve que la richesse d'un groupe affecte la richesse de l'autre. Les auteurs ont egalement examinele patron de la domi- nance pour constater que les plantes indigenes ont autant de chance de devenir dominantes que les especes envahissantes. On retrouve la dominance surtout dans les lacs peu profonds aforte productivite ´. Mots-cles: conditions abiotiques, biodiversite ´, structure des communautes, dominance, lacs, macrophytes. (Traduit par la Redaction)

Invasive species richness often is negatively correlated with native species richness at the small spatial scale of sampling plots, but positively correlated in larger areas. The pattern at small scales has been interpreted as evidence that native plants can competitively exclude invasive species. Large-scale patterns have been understood to result from environmental heterogeneity, among other causes. We investigated species richness patterns among submerged and floating-leaved aquatic plants (87 native species and eight invasives) in 103 temperate lakes in Connecticut (northeastern USA) and found neither a consistently negative relationship at small (3-m2) scales, nor a positive relationship at large scales. Native species richness at sampling locations was uncorrelated with invasive species richness in 37 of the 60 lakes where invasive plants occurred; richness was negatively correlated in 16 lakes and positively correlated in seven. No correlation between native and invasive species richness was found at larger spatial scales (whole lakes and counties). Increases in richness with area were uncorrelated with abiotic heterogeneity. Logistic regression showed that the probability of occurrence of five invasive species increased in sampling locations (3 m2, n = 2980 samples) where native plants occurred, indicating that native plant species richness provided no resistance against invasion. However, the probability of three invasive species' occurrence declined as native plant density increased, indicating that density, if not species richness, provided some resistance with these species. Density had no effect on occurrence of three other invasive species. Based on these results, native species may resist invasion at small spatial scales only in communities where density is high (i.e., in communities where competition among individuals contributes to community structure). Most hydrophyte communities, however, appear to be maintained in a nonequilibrial condition by stress and/or disturbance. Therefore, most aquatic plant communities in temperate lakes are likely to be vulnerable to invasion.

The use of biosolids compost, in the formulation of media used in the commercial production of container grown nursery crops, has been slow in the Northeast region of the United States. When biosolids compost is used in growing media, it is limited to small percentages. Regulations in Connecticut restrict the use of most biosolids compost to growing media for containerized ornamental plants and landfill cover. Information on the benefits of using biosolids compost, to grow a wide range of plant species in containers, could increase usage by nurseries. Seven species of flowering annuals, nine species of herbaceous perennials and eight species of woody ornamentals were grown in media containing 0, 25, 50, and 100 percent (by volume) biosolids compost, in combination with a mixture of bark, peat and sand. Biosolids compost came from the Metropolitan District Corporation (MDC) facility in Hartford, Connecticut. It was a mixture of wood chips and digested biosolids (3:1 by volume). Optimal plant growth general...

Biosolids compost is used in media to grow potted plants. Nitrogen (N) in media leachate may contribute to nitrate (NO3‐N) contamination of surface or ground water. Addition of sawdust to potting media containing biosolids compost will increase the carbon (C) to nitrogen ratio and could prevent N leaching without adversely affecting plant growth. A control medium containing 0% sawdust (v/v), 30% perlite, 50% municipal biosolids compost, and 20% sand was modified to contain either 10, 20, or 30% (v/v) fresh hardwood sawdust. The sawdust replaced either 1/3, 2/3, or all of the perlite in the control medium. Slow release fertilizer, slow plus quick release fertilizer, or no fertilizer was added to each of the four media to determine how the sawdust affected fertilizer needs. Coreopsis (Coreopsis grandiflora L.) and Rudbeckia (Rudbeckia hirta L. ’Goldstrum') were grown in pots for five months. Leachate was tested for NO3‐N and ammonium N (NH4‐N). Increasing amounts of sawdust produced no differences ...

The leaching of arsenic (As) from plant growth medium, admixed with different proportions of composted biosolids in field containers, was determined over a four-month period. Eight-week-old perennial flowers, Coreopsis grandiflora L, were transplanted in the field in 2-L containers filled with plant growth media. The treatments were replicated three times and rainfall was supplemented to supply 2 cm of water per day. Water percolating through potted plant containers was collected biweekly and analyzed for As using graphite furnace atomic spectrometry. The concentrations of As in the leachates increased with increasing proportions of compost in the medium and decreased with time of leaching, generally remaining below the drinking water standard of 50 μg/L after two months. Leaching of As occurred at a rapid rate initially but then continued at a slow rate. Compared to other metals of concern, as Cd, Cr, Ni and Pb, As in the compost appeared more mobile.

A conventional potting media containing peat moss, softwood bark and sand was amended to contain 0,25,50,75 and 100 (percent vol−1) municipal compost made from yard waste and biosolids. Each medium was adjusted with limestone and sulfur to an approximate pH of 5.0, 6.0 or 7.0. Rhododendron Panticum L. ‘Anah Kruschke’ (Rhododendron), Thujia occidentalis L. (Arborvitae) and Rudbeckia hirta L. ‘Goldilocks’ (Black-eyed Susan) were grown in each medium and pH level for 18 months. Leachate from pots was tested for NO3-N and NH3-N+NH4-N to determine how media pH and the amount of compost effected the potential for potting media to be a source of nitrate in surface and ground water.Media pH affected plant growth more than the percent compost. Compared to media with a pH of 7.0, statistically significant increases in the growth of Rhododendron occurred in media with a pH of 5.0 or 6.0. This pH effect was similar but less pronounced for Thujia. Growth of Rudbeckia was not effected by media pH or percent compost. Me...

The leaching of heavy metals from plant growth medium, admixed with different amounts of compost (prepared from sewage sludge and yard waste) at pH 5, 6 and 7 was determined over a six-month period. Twelve-week old rhododendron cuttings were planted in 2-L containers and rainfall was supplemented with irrigation to supply two centimeters of water per day. Leachates collected over each two to four week period were analyzed for Cd, Cr, Cu, Ni, Pb and Zn using atomic spectrometry. The concentrations of Cd, Cu, Ni and Zn in the leachates increased with increasing proportions of compost in the medium and decreased with increasing time of leaching. Decreasing media pH dramatically increased the concentrations of Cd, Ni and Zn in the leachates, but had no effect on the Cu concentrations. For example, as the proportion of the compost in the pH 5 medium increased from 0 to 100 percent, the concentrations of metals (μg L−1) in the leachates collected during the first two weeks increased from 1 to 33 (Cd), 10 to 123...

Deficiencies in soil zinc (Zn) may limit yield of corn (Zea mays L.) in parts of the northeastern United States. Because phosphorus (P) fertilizer is usually applied in excess of what is removed by the crop, buildup of P could reduce the plant availability of Zn. This study examines the effects of P and Zn fertilizer on yield of corn and levels of P and Zn in soil and tissue. Compared to corn that received no P or Zn, the yield of grain increased in three years when 66 kg/ha P + 0 kg/ha Zn and 66 kg/ha P + 15 kg/ha Zn was applied. When corn was fertilized with 0 kg/ha P + 15 kg/ha Zn, grain yield increased in one year. Similarly, an increase in grain yield occurred in only one year in plots fertilized with 66 kg/ha P + 15 kg/ha Zn compared to 66 kg/ha P + 0 kg/ha Zn. Increases in grain yields ranged between 5 and 22 percent for plots receiving P alone and P plus Zn, and between 5 and 10 percent for plots fertilized with Zn alone. Silage yields followed the same trends as the grain yields except t...

The leaching of heavy metals in source-separated municipal solid waste (MSW) compost was determined by irrigation leaching of growth medium, admixed with varying amounts of compost, used for container grown plants. Perennial flowers (black-eyed Susan, Rudbeckia hirta L.) were grown in 2-L containers filled with the growth medium for a 10-wk period. Rainfall was supplemented with overhead irrigation to supply 2 cm of water per day. Leachates collected over each 2-wk period were analyzed for Cd, Cr, Cu, Ni, Pb, and Zn using atomic spectrometry. Concentrations of the heavy metals in the leachates increased with increasing proportions of MSW compost in the growth medium, but decreased with time of leaching. Leaching of the metals occurred at relatively high concentrations initially, followed by continued leaching at low concentrations. The initial leaching of heavy metals is attributed to their soluble or exchangeable forms and the subsequent slow leaching to the solid compounds. The concentrations of the heavy metals remained below the current drinking water standards in all treatments throughout the leaching period. The results thus suggest that contamination of groundwater with heavy metals from source-separated MSW compost applied as a soil amendment should be negligible, as the low concentrations in the leachatesmore » leaving the surface soil would be further attenuated by the subsoil. 29 refs., 6 figs., 1 tab.« less

Composts made from coffee processing residue (CFPR), source separated municipal solid waste (MSW), sewage sludge and wood chips (SSWC), and sewage sludge, wood ash, wood chips and leaves (SSACL) were examined as replacements for the peat, perlite and sand found in a conventional potting medium. The perennial flower Rudbeckia hirta L. ‘Goldilocks’ (Black-Eyed Susan) was grown in media composed of 0, 10, 25, 50, 80, and 100 (percent by vol) of each compost. Leachate from media containing 0, 25, 50, and 100% compost was tested for NO3-N and NH3-N + NH4-N to determine if compost would increase the potential for potting media to be a source of nitrate in surface and ground water. The effects of two mid season applications of liquid fertilizer on plant growth and nitrogen leaching were also examined.Compared to a conventional medium without compost, differences in the growth of Rudbeckia in media with compost were few. Statistically significant decreases in growth occurred in media containing 80 and 100% CFPR, ...

Correspondance: Molecular Ecology Resources Primer Development Consortium, E-mail: editorial.office@molecol.com; International audience; This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species.

Municipal leaves, sewage sludge, and street sand were composted by a modified Beltsville aerated pile technique. Rooted cuttings of Aster novi-belgii L. ‘Peter Harrison,’ Gaura Lindheimeri Engelm. & A. Gray and Sedum purpurem (L.) Link ‘Autumn Joy’ were grown for 4 months in 2 1 (2 qt) containers filled with media containing 0, 10, 30, 60, 80 and 100 (percent by vol) compost. The medium with 0% compost contained loamy sand topsoil, peat, sand and Styrofoam pellets (1:5:2:2 by vol). The pH of all media was between 6.0 and 7.0. Half the containers in each treatment received liquid fertilization in mid-season and half did not. Leachate from the containers was collected at monthly intervals and analyzed for the heavy metals Cd, Cr, Cu, Mn, Ni, Pb and Zn to determine their potential for leaching. Growth of perennials was equal or greater in all media containing compost, compared to the medium containing no compost. Liquid fertilizer further improved growth. Adding compost increased media aeration, available plant nutrients and heavy metals and decreased moisture retention and bulk density. Heavy metal concentrations in leachate were low, probably due to the near neutral media pH, and not likely to pose an environmental risk.

Sewage treatment biosolids are composted at 198 facilities in the United States (Goldstein 1998). Amending potting media, used in the commercial production of ornamental plants, with biosolids compost is considered a prime use (Bugbee 1996). Biosolids compost contains substantial amounts of the plant nutrients nitrogen (N) and phosphorus (P). If these nutrients leach from the potting media they can become a pollutant. Nitrate (N03-N) is the most common chemical contaminant in drinking water wells (USEPA 1990) and non-point sources of N may contribute to low oxygen levels in marine estuaries (Frink 1991). Phosphorus enrichment of freshwater ponds and lakes promotes the growth of nuisance algae (Frink and Norvell 1984). Strategies are needed to help prevent N and P in potting media containing biosolids from leaching to the environment.

Providing optimum aeration for plants grown in small pots is a primary concern in the development of potting media. Aeration is defined as the percentage by volume of air-filled pores in a medium after it has been saturated with water and allowed to drain. This study describes how the physical properties of media, as well as the growth of potted plants, varied with changes in media aeration. A 1:1 (vol/vol) peat-vermiculite potting medium was adjusted to aerations of 1.0, 2.2, 5.0, 11.3, 13.3, 20.0, and 33.6%/vol by altering the particle size of the two constituents. Total pore space remained constant as aeration increased, but total moisture-holding capacity declined linearly. Water held above a matric potential of −30 cb increased slightly until aeration reached 10 to 15% and then declined. Water held below a matric potential of −30 cb decreased curvilin-early with increasing aeration. Four potted plants, begonia, coleus, impatiens and schefflera were grown in media with the seven different aerations. Although the plants varied in their sensitivity to aeration, plant growth was most limited when aeration was 5.0%/vol and below. Plants generally grew best in the aeration range of 11.3 to 20.0%/vol with a slight decrease in growth at the highest aeration of 33.6%/vol.