MBSS Site Summary for: PAXL-211-A-2011

Site Photos

Field photo showing stream conditions at site PAXL-211-A-2011-1 (Opens in a new window) Field photo showing stream conditions at site PAXL-211-A-2011-2 (Opens in a new window)

Located on ROCK CREEK in the Patuxent River lower watershed, 8-digit code: 02131101.
This stream was visited in the spring on 3/15/2011 and again in the summer on 6/28/2011.

Index of Biotic Integrity (IBI) Results:

An Index of Biotic Integrity (IBI) is a scientific tool used to identify and classify stream health. An IBI associates anthropogenic influences on a stream or with biological condition in the stream, and is formulated using data developed from biosurveys.
Details on the development and application of MBSS IBIs are in this document.
Fish IBI Good - 4.3 / 5.0
Benthic IBI Good - 4.4 / 5.0

Land Use

Land use can provide important information for determining stream health.
(Hint: Screen readers will announce definitions; mouse users can hover over dotted text.)
Catchment area 4,976 acres A stream flowing through a densely forested area. An example of a forested stream.
Urban Land Use 10 %
Agricultural Land Use 20.2 %
Forested Land Use 63.2 %


Stream showing woody debris, logs, and rocky substrate.
An example of woody debris in a stream.

Physical Stream Habitat
Instream Habitat 17/20 (Optimal)
Epifaunal Substrate 16/20 (Optimal)
Velocity/Depth Diversity 14/20 (Suboptimal)
Pool Quality
Pool Extent = 66 meters 		18/20 (Optimal)
Riffle Quality
Riffle Extent = 9 meters 		15/20 (Suboptimal)
Shading 80 %
Embeddedness 45 %
Several measures of instream habitat were considered 'Optimal' at this location.


Stream Water Quality:
pH (lab) 6.705
Alkalinity
(acid neutralizing capacity) 		150.6 µeq/L
Dissolved organic carbon (DOC) 3.1372 mg/L

Biological Stream Condition:

Surveys of the organisms living within a stream can give indications of stream health. Species richness, or the number of different species present, as well as indicator species (species whose presence, absence or abundance can serve as a measure of environmental conditions) are informative for stream health. 		Close-up of a mayfly indicator species.

Fish Survey Results:
The following 12 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
Blacknose Dace 33
Fallfish 32
Creek Chubsucker 20
Eastern Mosquitofish 17
Tessellated Darter 14
Eastern Mudminnow 11
Pumpkinseed 7
Yellow Bullhead 4
Least Brook Lamprey 3
Green Sunfish 2
American Eel 1
Rosyside Dace 1
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
Eastern Cricket Frog
Northern Green Frog
Northern Spring Peeper
Southern Leopard Frog

Crayfish:
Orconectes limosus

Exotic Plants:
Japanese Stiltgrass
Multiflora Rose
 

Benthic Macroinvertebrates:
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Genus/Family Common Name Count
Prostoia Spring Stonefly 33
Isoperla Stripetail Stonefly 23
Acerpenna Tiny Blue-Winged Olive Mayflies 7
Tanytarsus Non-Biting Midges 3
Hydrobaenus Midge 3
Paratanytarsus Non-Biting Midges 3
Polypedilum Non-Biting Midges 2
Rheocricotopus Non-Biting Midges 2
Rheotanytarsus Non-Biting Midges 2
Strophopteryx Early Brown Stonefly 2
Triaenodes Long-Horned Caddisfly 2
Paraphaenocladius Non-Biting Midges 2
PERLIDAE Common Stonefly 2
LEPTOPHLEBIIDAE Pronggilled Mayfly 2
Ancyronyx Spider Riffle Beetle 2
Cordulegaster Spiketail Dragonfly 1
Ephemerella Sulphur Mayfly 1
LIBELLULIDAE Skimmer Dragonfly 1
Thienemanniella Non-Biting Midges 1
Polycentropus Tube Maker Caddisfly 1
Dineutus Whirlygig Beetle 1
LUMBRICULIDAE Worm 1
Pseudolimnophila Crane Fly 1
Prosimulium Black Fly 1
Hagenius Clubtail Dragonfly 1
Orthocladiinae Midge 1
Cheumatopsyche Net-Spinning Caddisfly 1
Corynoneura Non-Biting Midges 1
Orthocladius Non-Biting Midges 1
Parakiefferiella European Non-Biting Midge 1
Kick net sampling for macroinvertebrates.
Sampling with a kick net.

Information disclaimer: The information and data on this page is for guidance and general planning purposes only. It should not be used to make decisions on specific matters.