Seasonal Biomass and Carbohydrate Allocation Patterns in Southern Minnesota Curlyleaf Pondweed Populations

Four southern Minnesota populations of curlyleaf pondweed ( Potamogeton crispus L.) were sampled monthly from January 2001 to November 2002 to determine seasonal phenological, biomass, and carbohydrate allocation patterns. Low periods of carbohydrate storage in the seasonal phenological cycle indicate potentially vulnerable periods in the plant’s life cycle and may be the ideal time to initiate management and control efforts.

Monitoring hydrilla using two RAPD procedures and the Nonindigenous Aquatic Species database

Hydrilla ( Hydrilla verticillata (L.f.) Royle), an invasive aquatic weed, continues to spread to new regions in the United States. Two biotypes, one a female dioecious and the other monoecious have been identified. Management of the spread of hydrilla requires understanding the mechanisms of introduction and transport, an ability to map and make available information on distribution, and tools to distinguish the known U.S. biotypes as well as potential new introductions. Review of the literature and discussions with aquatic scientists and resource managers point to the aquarium and water garden plant trades as the primary past mechanism for the regional dispersal of hydrilla while local dispersal is primarily carried out by other mechanisms such as boat traffic, intentional introductions, and waterfowl. The Nonindigenous Aquatic Species (NAS) database is presented as a tool for assembling, geo-referencing, and making available information on the distribution of hydrilla. A map of the current range of dioecious and monoecious hydrilla by drainage is presented. Four hydrilla samples, taken from three discrete, non-contiguous regions (Pennsylvania, Connecticut, and Washington State) were examined using two RAPD assays. The first, generated using primer Operon G17, and capable of distinguishing the dioecious and monoecious U.S. biotypes, indicated all four samples were of the monoecious biotype. Results of the second assay using the Stoffel fragment and 5 primers, produced 111 markers, indicated that these samples do not represent new foreign introductions. The differences in the monoecious and dioecious growth habits and management are discussed.

Influence of Sediment Nutrients on Growth of Emergent Hygrophila

Hygrophila ( Hygrophila polysperma (Roxb.) T. Anderson) is a plants which forms serious aquatic weed problems. Both submerged and emergent growth forms occur. Nutritional studies with a controlled release fertilizer and sediments collected from hygrophila-infested areas were conducted with the emergent growth habit to provide insights into growth of this introduced plant. Plant dry weights for experimental 16- week culture periods with low average temperatures were associated with low amounts of hygrophila biomass as compared to culture periods with high average temperatures. Hygrophila cultured in sand rooting media with the controlled release fertilizer produced as much as 20 times more dry weight than plants cultured in sediments only. First-degree linear regression statistics showed hygrophila dry weights were highly related to ammonia nitrogen, magnesium, sodium, and pH values in the sediments. These findings show the close relationship of the emergent growth habit of hygrophila to sediment nutrients. Analyses for certain sediment characteristics may provide an indication of the potential growth that may be expected for weed infestations of this plant. Hygrophila grows year round in south Florida; however, visual observations of canals and other bodies of water indicate that lower amounts of hygrophila plants occur during the cooler months of year than during the summer season. These findings show the seasonal growth of emergent hygrophila occurs with biomass dependent on both sediment nutrients and temperature.

Letter from the Editor: special issue of papers on “The Use of Native Insect Herbivores for the Management of Eurasian Watermilfoil," presented at a special session of the Annual Meeting, Aquatic Plant Management Society, July 1998, Memphis, TN

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The weevil-watermilfoil interaction at different spatial scales: what we know and what we need to know

The North American weevil ( Euhrychiopsis lecontei (Dietz)) is being considered as a biological control agent for Eurasian watermilfoil ( Myriophyllum spicatum L.). This native insect damages watermilfoil plants and is frequently associated with declining watermilfoil populations

Temporal and spatial changes in milfoil distribution and biomass associated with weevils in Fish Lake, WI

During the course of an eight year monitoring effort, the Wisconsin Department of Natural Resources documented a significant decline in milfoil biomass and distribution in Fish Lake, Wisconsin. Average milfoil biomass declined by 40- 50% from 374-524 g dw m -2 during 1991-93 to 265 g dw m -2 during both 1994 and 1995. Milfoil recovered fully in 1996- 98 to 446- 564 g dw m -2 . The size of the milfoil bed, as discerned from aerial photographs, shrank from a maximum coverage of 40 ha in 1991 to less than 20 ha during 1995. During the “crash” of 1994-95, milfoil plants exhibited typical signs of weevil-induced damage, including darkened, brittle, hollowed-out growing tips, and the arching and collapse of stems associated with loss of buoyancy. Monitoring of weevils and stem damage during 1995-98 showed highest densities and heaviest damage occurred near shore and subsequently fanned out into deeper water from core infestation sites each spring. The extent of milfoil stem damage was positively correlated with weevil densities (monthly sampling). However, weevil densities and stem damage were lower during 1995 (when milfoil biomass was in decline) than during 1996-98 (when milfoil biomass was fully recovered).

Common Coastal Plants in Florida: a guide to planting and maintenance

(PDF has 125 pages.)

Exploring the Metrics of the Aquatic Commons repository

17 slide Powerpoint presentation on the deposit and download rates associated with Aquatic Commons from its founding in August 2007 to April 2009.

An analysis of poverty and aquatic resources use - focusing especially on the livelihoods of the poor - in Cambodia

The main objectives of this report, which is based on the current literature and key informant interviews, is to assess and analyse the nature and distribution of poverty and aquatic resources use, focusing especially on the livelihoods of the poor. It describes and reports different ways of measuring poverty that are used in Cambodia and quantifies the diverse nature and geographic distribution of aquatic resources use in Cambodia. (PDF contains 55 pages)

Seagrass and Aquatic Habitat Assessment Workshop Summary

Seagrass communities are among the richest and most productive, photoautotrophic coastal systems in the world. They protect and improve water quality, provide shoreline stabilization, and are important habitats for an array of fish, birds, and other wildlife. Hence, much can be gained by protecting and restoring these important living resources. Human’s impact on these vital resources from population growth, pollution, and physical damage from boating and other activities can disrupt the growth of these seagrasses communities and have devastating effects on their health and vitality. Inventory and monitoring are required to determine the dynamics of seagrasses and devise better protection and restoration for these rich resources. The purpose of this seagrass workshop, sponsored by NOAA’s CSC , USGS, and FMRI, was to move toward greater objectivity and accuracy in seagrass mapping and monitoring. This workshop helped foster interaction and communication among seagrass professionals. In order to begin the process of determining the best uniform mapping process for the biological research community. Increasing such awareness among the seagrass and management communities, it is hoped that an improved understanding of the monitoring and mapping process will lead to more effective and efficient preservation os submerged aquatic vegetation. (PDF contains 20 pages)

Assistance in poverty alleviation through improved aquatic resources management in Asia-Pacific: DoF/NACA-STREAM/FAO Workshop on livelihoods approaches and analysis. Yangon, Union of Myanmar, 11-15 May 2004

This is the report of the “DoF/NACA-STREAM/FAO Workshop on Livelihoods Approaches and Analysis” that was conducted in Yangon, Union of Myanmar from 11-15 May 2004. The purpose of the workshop was to develop and document mechanisms for training in livelihoods approaches and analysis, and to build national capacity to conduct livelihoods studies. The workshop in Yangon was the first STREAM event in Myanmar, with colleagues coming to participate from Yangon and many Divisions and States throughout the country. The workshop in Yangon was the fourth in a series, the first of which was held in Iloilo City, Philippines, in November 2003, the second in Ranchi, India, in February 2004, and the third in Vientiane, Lao PDR in March 2004. A subsequent workshop will take place in Yunnan, China. The objectives of the workshop were to: Understand issues of interest to people whose livelihoods include aquatic resources management, especially those with limited resources Build “(national) livelihoods teams” to do livelihoods analyses and training, and share their experiences with communities and other stakeholders Share understandings of livelihoods approaches and analysis using participatory methods Review current NACA-STREAM livelihoods analysis documentation, adapt and supplement, towards the drafting of a Guide for Livelihoods Analysis Experience the use of participatory tools for livelihoods analysis Plan activities for carrying out livelihoods analyses, and Consider how to build capacity in monitoring and evaluation (M&E) and “significant change”. (Pdf contains 56 pages).

Self-recruiting species (SRS) from farmer managed aquatic systems: are they important to the livelihoods of rural communities?

Why are SRS important? The answer is to be found in this well-structured survey under: SRS as food source; SRS as additional source of cash income; Role of SRS in social capital. An analysis of the threats to SRS and the potential management options for farmer managed aquatic systems are also available in this survey along with the following definition of SRS: SRS are defined as aquatic animals that can be harvested from farmer managed aquatic systems without regular stocking. (PDF contains 4 pages)

Aquatic resources in the Philippines and the extent of poverty in the sector

This report presents an overview of the state of aquatic resources in the Philippines, its performance and importance in the Philippine economy, and explores the situation of poverty in the "aquatic resources sector." The report describes the policy environment that guides the action of key actors in the sector. The report also provides a general analysis of some trends in relation to factors that keep the poor from participating and benefiting from aquatic resource management, based on the perspectives of the authors. (PDF contains 135 pages)