Notes on Diatoms V. : Epilithic Diatom Biomass in the Des Moines River

Luxuriant epilithic growths of the diatom, Gomphonema olivaceum (Lyngbye) Kutz., were observed to be growing throughout a 320 km section of the Des Moines River. Flat rocks covered with the diatom growth were collected and the live weight of the diatom biomass per square centimeter was determined to be 0.7 gm. This included 0.021 gm dry weight of organic matter. Using these values, the standing epilithic diatom biomass in one 6 km section of the river was estimated to be 1260 metric tons (live weight) containing 37.6 metric tons dry weight of organic matter. The bulk of the growth consisted of polysaccharide material secreted as tubular stalks by G. olivaceum. Extensive growths were usually limited to rocky shoals and riffle areas, composed of either cobbles and boulders of glacial origin, or of rock rubble of local origin

Diatoms In The Des Moines River

Diatoms were observed to be the dominant algal group in all seasons in the 860 km long Des Moines River, from April 1961 through September 1964. The 9 most abundant diatom taxa were: Diatoma vulgare, Gomphonema olivaceum, Melosira granulata, Nitzschia dissipata, N. palea, Stephanodiscus hantzschii, Synedra acus and S.ulna. Of the 60 most abundant diatom taxa in the Des Moines River, 36 are important components of diatom floras in other major United States Rivers. From over 600 samples collected year around and throughout the length of the river, 274 diatom taxa representing 38 genera were identified. No new diatom taxa were recognized. Diatoms and a water sample were collected weekly. Water samples were analysed for: temperature, pH, turbidity, sulfate, iron, phosphate, silica, nitrite, nitrate, methyl orange alkalinity, chloride, calcium hardness, total hardness, oxygen, and manganese. The river basin climate produced 5 distinct positive growth periods for diatoms each year; these were characterized by heavy benthic, attached, and planktonic (except in winter) diatom growth; and delimited or terminated by one of 5 distinct respective \u27\u27antigrowth periods\u27\u27 of highwater. The latter periods were typified by heavy silt loads, and removal of most diatoms from the river by flushing and scouring. Sources of diatoms for repopulating the river were the two headwater lakes, numerous tributaries, migratory animals, and impoundments in the upper and middle zones of the river itself. Motility is an important survival factor for diatoms settling out with silt in river impoundments, and 80% of the Des Moines River diatoms are motile forms. Flow (water volume) and available light were probably the most important limiting factors for diatom growth in all seasons in the Des Moines River, both in turn limited by precipitation in the drainage basin. Light penetration most probably was limited by ice and snow cover and turbidity; in addition to precipitation, high turbidity was also caused by effluents from commercial washing of sand and gravel. Seasonal temperature variation also regulated the kinds of dominant and abundant diatoms. Ample nutrients, especially nitrates and phosphates, for diatom growth were provided by inorganic fertilizers washed from farmlands and sewage and related effluents from over 500,000 people. The intrinsic fertility of the Des Moines River is insignificant under these conditions. It is estimated that during positive growth periods over l000 tons per month of diatoms and other algae were produced in and carried out of the river; the vast amount of diatom primary production in the Des Moines River is probably utilized negligibly by other organisms. Two large dams, at Saylorville and Red Rock, will alter the diatom growth patterns in the Middle and Lower portions of the river as well as providing the opportunity for a stratified sedimentary deposition of diatoms. The impoundments from these dams will probably result in a change in the kinds of dominant diatoms and increase the number of taxa collectable

Notes on Iowa Diatoms III. Occurrence of the Genus Pleurosigma in the Des Moines River

A member of the diatom genus Pleurosigma was collected from the Des Moines River from 12 stations. Earlier investigators did not report it. This organism may be suitable as an ecological indicator, since most members of the genus occur in salt or brackish water. Positive identification was not made, the organism is probably a variety of P. delicatulum Wm. Smith

Implications of Spatially Variable Costs and Habitat Conversion Risk in Landscape-Scale Conservation Planning

‘‘Strategic habitat conservation’’ refers to a process used by the U.S. Fish and Wildlife Service to develop cost-efficient strategies for conserving wildlife populations and their habitats. Strategic habitat conservation focuses on resolving uncertainties surrounding habitat conservation to meet specific wildlife population objectives (i.e., targets) and developing tools to guide where conservation actions should be focused on the landscape. Although there are examples of using optimization models to highlight where conservation should be delivered, such methods often do not explicitly account for spatial variation in the costs of conservation actions. Furthermore, many planning approaches assume that habitat protection is a preferred option, but they do not assess its value relative to other actions, such as restoration. We developed a case study to assess the implications of accounting for and ignoring spatial variation in conservation costs in optimizing conservation targets. We included assumptions about habitat loss to determine the extent to which protection or restoration would be necessary to meet an established population target. Our case study focused on optimal placement of grassland protection or restoration actions to influence bobolink Dolichonyx oryzivorus populations in the tallgrass prairie ecoregion of the north central United States. Our results show that not accounting for spatially variable costs doubled or tripled the cost of meeting the population target. Furthermore, our results suggest that one should not assume that protecting existing habitat is always a preferred option. Rather, our results show that the balance between protection and restoration can be influenced by a combination of desired targets, assumptions about habitat loss, and the relative cost of the two actions. Our analysis also points out how difficult it may be to reach targets, given the expense to meet them. We suggest that a full accounting of expected costs and benefits will help to guide development of viable management actions and meaningful conservation plans

Notes on Iowa Diatoms. VI. Frustular Aberrations in Surirella Ovalis

Two types of frustular aberrations in cultures of Surirella ovalis Breb. have been observed. The first is a notch deformity occurring in approximately 0.1% of the population. It is produced by mechanical distortion where the cells are crowded. This deformity is passed to daughter cells in each successive vegetative division. The second type is characterized by the presence of one or more aberrant raphe canals crossing the valve face in various directions. It occurred only in cultures exposed to continuous light for two weeks. Little or no cell division occurred during this period. The raphe canal aberrations, which occurred in about 0.01% of the exposed population, may have resulted from abortive cell divisions. They were not observed to continue in later transfers of the exposed populations to normal growth conditions

The Integrated Monarch Monitoring Program: From Design to Implementation

Steep declines in North American monarch butterfly (Danaus plexippus) populations have prompted continent-wide conservation efforts. While monarch monitoring efforts have existed for years, we lack a comprehensive approach to monitoring population vital rates integrated with habitat quality to inform adaptive management and effective conservation strategies. Building a geographically and ecologically representative dataset of monarchs and their habitat will improve these efforts. These data will help track long-term changes in the distribution and abundance of monarchs and their habitats, refine population and habitat models, and illuminate how conservation activities affect monarchs and their habitats. The Monarch Conservation Science Partnership developed the Integrated Monarch Monitoring Program (IMMP) to profile breeding habitats and their use by monarchs in North America. A spatially balanced random sampling framework guides site selection, while also allowing opportunistic inclusion of sites chosen by participants, such as conservation areas. The IMMP weaves new protocols together with those from existing monitoring programs to improve data compatibility for assessing milkweed (Asclepias spp.) density, nectar resources, monarch reproduction and survival, and adult monarch habitat use. Participants may select a protocol subset according to interests or local monitoring objectives, thereby maximizing contributions. Conservation partners, including public and private land managers, academic researchers, and citizen scientists contribute data to a national dataset available for analyses at multiple scales. We describe the program and its development, implementation elements that make the program robust and feasible, participation to date, and how IMMP data can advance research and conservation for monarchs, pollinators, and their habitats