Study of Benthic Macroinvertebrates in Relation to the Restoration of Smith Creek Reese Voshell, Tar

1
Study of Benthic Macroinvertebrates in Relation
to the Restoration of Smith CreekReese Voshell,
Tara Willey, and Amy BracciaDepartment of
Entomology, Virginia Tech
Hypotheses The current benthic macroinvertebrate
assemblage in the restoration zone is determined
by habitat and food variables related to
agricultural land use. As the riparian area of
Bruce Farm becomes forested, the benthic
macroinvertebrate assemblage will become more
similar to that of the Mixed Use zone.
Introduction Scientists from Virginia Tech
collected benthic macroinvertebrate, habitat, and
environmental data in Spring and Summer 2006 to
characterize pre-restoration (baseline)
conditions in Smith Creek. Six reaches within
the Bruce Farm (Restoration Zone) and three
upstream reaches that had forested buffer and
moderate agriculture (Mixed Use Zone) were
sampled.
What are benthic macroinvertebrates ?
Benthic - bottom dwelling (on, protruding above,
in) Macro - large enough to see with unaided
eye Invertebrate - without backbone

• Objectives
• Characterize baseline macroinvertebrate
  assemblage structure and function
• Quantify primary environmental variables
  responsible for baseline assemblage
• Track spatial and temporal changes in benthic
  macroinvertebrates in response to changes in
  environmental variables from stream restoration

Mixed Use

• Why should they be included in stream
  restoration?
• Stream restoration is supposed to help achieve
  the primary purpose of the Clean Water Act
• to restore and maintain the chemical, physical,
  and biological integrity of the Nations waters
• Benthic macroinvertebrates are part of biological
  integrity
• a balanced, integrated, adaptive community of
  organisms having a species composition,
  diversity, and functional organization comparable
  to that of natural habitat of the region
• As part of biological integrity they perform
  essential ecological functions in communities and
  ecosystems, such as trophic dynamics
• Shredders initiate decomposition of terrestrial
  detritus
• Scrapers contribute to energy flow from
  photosynthetic algae attached to rocks
• Filterers Clean the water and retard the
  downstream export of fine particles of organic
  matter

Preliminary Results Concentrating on 10
assemblage-level metrics

• Percent EPT
• Percent Coleoptera
• Percent Hydropsychidae
• of total Trichoptera
• Percent Clinger
• Percent Crawlers

• Hilsenhoff Biotic Index
• Total Richness
• Percent Scrapers
• Percent Collector Filterers
• Percent Shredders

Methods

• Habitat
• current
• depth
• Fredle index
• Trasks sorting
• coefficient
• cobble
• gravel
• pebble
• fines

• Food
• epilithic biomass
• chlorophyll a
• autotrophic index
• FBOM
• CBOM
• deciduous leaves
• wood
• pasture vegetation
• moss

• Benthic Macroinvertebrates
• Modified stove pipe sampler
• sort, identify, count
• Metric categories
• trophic status
• habits
• community balance
• richness
• pollution tolerance

R2 0.511 P lt 0.0001
R2 0.281 P lt 0.0001