Recovery Of Macroinvertebrates Research Articles

Wetland plant and macroinvertebrate recovery in Phragmites australis-dominated stands after herbicide (Habitat®) treatment

Wetland plant and macroinvertebrate recovery in <i>Phragmites australis</i>-dominated stands after herbicide (Habitat®) treatment

Macroinvertebrate assemblages in streams of interior Alaska following alluvial gold mining

AbstractAlluvial gold mining, or placer mining, represents a major disturbance to stream ecosystems in interior Alaska. This process typically involves re‐routing the stream to one side of the valley while the gravels are removed across the floodplain for processing. The stream is then re‐directed back into a reclaimed new channel after mining has ceased in that section of stream. Macroinvertebrate colonization of reclaimed stream reaches is necessary for benthic community recovery following mining. Macroinvertebrate community assemblages at 36 sites on six streams in interior Alaska were examined. Sites with different mining histories were compared to control sites. TWINSPAN classification and ordination of sites using macroinvertebrate abundance indicated a greater similarity of sites within watersheds than between watersheds even though each watershed had a history of mining including recently mined sites. Significant differences were found for total invertebrate abundance, percentage dominant taxon and mean total biomass of macroinvertebrates between control sites and sites that were recently mined (≤10 years) and sites mined 12–50 years ago. Total macroinvertebrate abundance and biomass was lower and taxon dominance higher in both groups of sites with a history of mining. No significant difference in these or other measures was found for sites where mining occurred upstream. There was also no significant relationship between time since mining and the biotic measures used to summarize macroinvertebrate community structure. Although taxon richness recovered rapidly, no individual taxon was found to be a specific indicator of macroinvertebrate recovery since mining. Copyright © 2004 John Wiley &amp; Sons, Ltd.

Recovery of macroinvertebrates following catastrophic flooding in a temporary Mediterranean stream

Recovery of macroinvertebrates following catastrophic flooding in a temporary Mediterranean stream

Assessing Stream Ecosystem Rehabilitation: Limitations of Community Structure Data

AbstractInappropriate land use practices, pollutants, exploitation, and overpopulation have simplified stream habitats and degraded water quality worldwide. Management agencies are now being tasked to ameliorate impacts and restore stream “health,” yet there is a dearth of rigorous scientific methods and theory on which to base sound restoration design and monitoring. Despite this, many localized restoration projects are being constructed to stabilize erosion and enhance habitat heterogeneity in streams. Many restoration attempts adopt the paradigm that increasing habitat heterogeneity will lead to restoration of biotic diversity, yet there have been few studies that have manipulated variation of a physical parameter independent of the mean to isolate the effects of heterogeneity per se. We conducted a field experiment to mimic restoration of habitat heterogeneity in a shallow. stony stream. By using an experimental approach rather than a detailed assessment of existing restoration work, we were able to control the starting conditions of replicate riffles so that organism responses could be unambiguously attributed to the heterogeneity treatments. We successfully manipulated the variability of streambed particle sizes and consequently near‐bed flow characteristics of entire riffles. These factors define axes of habitat heterogeneity at scales relevant to the resident macroinvertebrate fauna. Despite this, we were unable to distinguish differences in community structure between high and low habitat heterogeneity treatments. Power analysis indicated that macroinvertebrate populations were more sensitive to individual site conditions at each riffle than to the heterogeneity treatments, suggesting that increasing habitat heterogeneity may be an ineffective technique if the restoration goals are to promote macroinvertebrate recovery in denuded streams. With extremely high variability between replicate riffles, monitoring programs for localized restoration projects or point source impacts are unlikely to detect gradual shifts in community structure until the differences between the reference and treatment sites are extreme. Innovative measurement of other parameters, such as ecosystem function variables (e.g., production, respiration, decomposition), may be more appropriate indicators of change at local scales.

Macroinvertebrate recovery of a post-thermal stream: habitat structure and biotic function

Macroinvertebrate faunal assemblages, organic matter availability and instream structural complexity were investigated in three systems to determine the current state of recovery of a post-thermal stream. The abundance and diversity of the lower foodchain community has recovered substantially since cessation of thermal flows in 1988; however, the biotic communities remain structurally and functionally distinct as a result of past thermal perturbation. Disparate instream habitat structural components and stream physical changes in the post-thermal and reference systems drive functional differences in the macroinvertebrate community. The post-thermal stream is physically and biologically structured by high densities of aquatic macrophytes, while the reference system is driven by high concentrations of coarse woody debris. Consequently, the abundant, diverse macroinvertebrate communities in both systems illustrate a post-thermal shift in energy source from a reliance on allochthonous to autochthonous inputs. Biotic indices such as taxa richness, a family level index and similarity index may not be sufficient to determine functional changes as a result of thermal impacts. However, the distribution of diverse functional feeding groups across streams was successful at characterizing divergence in resource utilization and processing. This distinction between macroinvertebrates’ abundance and diversity, and their function in the ecosystem is essential in establishing relevant mitigation plans and endpoints for stream restoration.

Temporal Variability of Stream Macroinvertebrate Abundance and Biomass Following Pesticide Disturbance

We determined the extent of macroinvertebrate recovery in a former pesticide-treated stream (FTS) relative to a reference stream (RS) by examining macroinvertebrates colonizing red maple (Acer rubrum L.) litter bags between 5 to 10 y following pesticide treatment. Mean abundance and biomass, variability in abundance and biomass (using the coefficient of variation [CV]), and assemblage structure were compared both within and among years to assess recovery. The 5 y of study included 3 drought years followed by 2 wet years. Mean total abundance and biomass of macroinvertebrates, and that of most functional feeding groups (FFG) did not significantly differ between streams during this study, nor did within-year variability of these means, indicating macroinvertebrates in FTS had recovered relative to RS. Some exceptions to the above patterns (shredder abundance and mean annual gatherer biomass) resulted from the dynamics of a single taxon in each group (Leuctra and Paraleptophlebia, respectively). Macroinverte...

Recovery of Macroinvertebrates by Screening in the Field: A Comparison between Coarse (1.18 mm)- and Fine (0.60 mm)-Mesh Sieves

ABSTRACT We evaluated the potential loss of target benthic macroinvertebrates from coarse-mesh field wash down of samples through a 1.18-mm mesh sieve nested on a 0.60-mm mesh sieve. Visible target organisms (midges, mayflies, and fingernail clams) in the 1.18-mm mesh sieve were removed from the sample and enumerated in the field. The entire contents of both sieves were preserved for subsequent laboratory enumeration under 4X magnification. Percent recoveries from each treatment were based on total intact organisms found in all sieves. Percent recovery for fingernail clams found in the field (31%) was lower than for mayflies (79%) and midges (88%). Laboratory enumeration of organisms retained by the 1.18-mm sieve yielded additional fingernail clams (to total 74% recovered in the field and lab), mayflies (to total 89%), and midges (to total 91%). If the 1.18-mm sieve is used alone in the field, it is adequate to monitor mayflies, midges >1 cm, and adult fingernail clams ≥5.0 mm shell length.

Low flows and recovery of macroinvertebrates in a small regulated chalk stream

AbstractThe ecological effects of, and subsequent recovery from, a protracted drought exacerbated by groundwater abstractions on a small English chalk stream are described. Preliminary data from 15 sites showed significant physical and biotic changes between two surveys (in 1992 and 1993) and between ‘upland’ and ‘lowland’ sectors. At the end of the drought (1992) the macroinvertebrate community was severely reduced in the upland sector—with low abundances and species richness—but recovery was dramatic with the return of normal flows. In contrast, relatively little change was observed in the lowland sector. The observed faunal differences are discussed in relation to information on the impact of previous droughts and recovery rates.

Diversity and community comparison indices: Assessing macroinvertebrate recovery following a gasoline spill

Diversity and community comparison indices were evaluated to determine their utility in quantifying macroinvertebrate response to a catastrophic gasoline spill into Wolf Lodge Creek, Idaho, U.S.A. The Shannon and Brillouin diversity indices, and the following community comparison indices were analyzed: (1) Jaccard's coefficient of similarity; (2) Renkonen's percentage similarity; (3) Bray-Curtis index; (4) Morisita's similarity index; (5) simplified Morisita index; (6) Canberra metric index; and (7) average χ 2 index. The Bray-Curtis and average χ 2 community comparison indices were more effective in quantifying differences in macroinvertebrate composition between gas-impacted and reference areas of Wolf Lodge Creek following the spill. In addition, these indices tracked the progressive spatial recolonization of macroinvertebrates during the 16 month recovery period. All other indices tested failed to adequately quantify macroinvertebrate community response to the gasoline spill.