MBSS Site Summary for: PAXM-102-X-2006


Located on Two-Run Branch 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 7/19/2006.

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 - 2.3 / 5.0
Benthic IBI Poor - 1.3 / 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 67 acres A stream flowing through a densely forested area. An example of a forested stream.
Urban Land Use 0 %
Agricultural Land Use 29 %
Forested Land Use 71 %


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

Physical Stream Habitat
Instream Habitat 4/20 (Poor)
Epifaunal Substrate 7/20 (Marginal)
Velocity/Depth Diversity 6/20 (Marginal)
Pool Quality
Pool Extent = 50 meters 		5/20 (Poor)
Riffle Quality
Riffle Extent = 29 meters 		3/20 (Poor)
Shading 95 %
Embeddedness 50 %
Several measures of instream habitat were considered 'Poor' at this location.


Stream Water Quality:
Water temperature 21.5 ° C
Dissolved oxygen (DO) 4 mg/L
Dissolved oxygen levels measured in the stream were very low (4 mg/L). Many fishes and other aquatic animals cannot tolerate low levels of oxygen in the water.
pH (lab) 6.97
Conductivity 113 µmho/cm
Alkalinity
(acid neutralizing capacity) 		232.8 µeq/L
Dissolved organic carbon (DOC) 2.1654 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 6 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
Blacknose Dace 54
Creek Chub 5
Rosyside Dace 4
American Eel 1
Green Sunfish 1
Least Brook Lamprey 1
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
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
Chaetocladius Non-Biting Midges 45
Diplocladius Non-Biting Midges 31
Gammarus Amphipod 13
Orthocladius Non-Biting Midges 9
Rheocricotopus Non-Biting Midges 5
Ironoquia Northern Caddisfly 3
Paraphaenocladius Non-Biting Midges 3
Corynoneura Non-Biting Midges 2
Orthocladiinae Midge 2
Amphinemura Spring Stonefly 2
Limnephilidae Northern Casemaker Caddisfly 1
Zavrelimyia Non-Biting Midges 1
Culicoides 1
Heterotrissocladius 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.