MBSS Site Summary for: PAXM-109-X-2006


Located on Black Walnut Creek in the Patuxent River middle watershed, 8-digit code: 02131102.
This stream was visited in the spring on 3/21/2006 and again in the summer on 7/5/2006.

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 Poor - 1.7 / 5.0
Benthic IBI Fair - 3.3 / 5.0

Land Use

Land use can provide important information for determining stream health.
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Catchment area 152 acres A stream flowing through a densely forested area. An example of a forested stream.
Urban Land Use 1 %
Agricultural Land Use 2 %
Forested Land Use 96 %


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

Physical Stream Habitat
Instream Habitat 8/20 (Marginal)
Epifaunal Substrate 9/20 (Marginal)
Velocity/Depth Diversity 7/20 (Marginal)
Pool Quality
Pool Extent = 65 meters 		6/20 (Marginal)
Riffle Quality
Riffle Extent = 25 meters 		7/20 (Marginal)
Shading 80 %
Embeddedness 95 %
The embeddedness, a measure of silt on the stream bottom, was 95%. This is relatively high, and may exclude some biota.


Stream Water Quality:
Water temperature 20.9 ° C
Dissolved oxygen (DO) 5.9 mg/L
pH (lab) 5.84
Conductivity 53 µmho/cm
Alkalinity
(acid neutralizing capacity) 		38.8 µeq/L
Dissolved organic carbon (DOC) 2.1257 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 2 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
Eastern Mudminnow 48
American Eel 1
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
Eastern Box Turtle
Northern Green Frog

Crayfish:
No crayfish noted.

Exotic Plants:
Japanese Stiltgrass
 

Benthic Macroinvertebrates:
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Genus/Family Common Name Count
Tanytarsus Non-Biting Midges 10
Orthocladius Non-Biting Midges 8
Tanypodinae Non-Biting Midges 7
Pseudolimnophila Crane Fly 7
Heterotrissocladius European Non-Biting Midge 7
Tipulidae Cranefly 6
Diplocladius Non-Biting Midges 6
Thienemannimyia group Non-Biting Midges 5
Parametriocnemus Non-Biting Midges 5
Zavrelimyia Non-Biting Midges 5
Limnephilidae Northern Casemaker Caddisfly 4
Gammarus Amphipod 4
Stegopterna Black Fly 3
Musculium Fingernail Clam 3
Paraphaenocladius Non-Biting Midges 3
Stempellinella Non-Biting Midges 3
Trissopelopia Non-Biting Midges 2
Apsectrotanypus Non-Biting Midges 2
Chrysops Deerfly 2
Bezzia Biting Midge 2
Culicoides 2
Mallochohelea 1
Tipula Crane Fly 1
Ceratopogon Biting Midge 1
Simuliidae Black Fly 1
Stenochironomus European Non-Biting Midge 1
Corynoneura Non-Biting Midges 1
Leptophlebiidae Pronggilled Mayfly 1
Leuctridae Rolledwinged Stonefly 1
Hydroporus Water Beetle 1
Hydrobius Water Scavenger Beetle 1
Lumbriculidae Worm 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.