MBSS Site Summary for: PAXM-104-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 3/20/2006 and again in the summer on 6/15/2006.

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 Good - 4.0 / 5.0
Benthic IBI Good - 4.4 / 5.0

Land Use

Land use can provide important information for determining stream health.
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Catchment area 606 acres A stream flowing through a densely forested area. An example of a forested stream.
Urban Land Use 1 %
Agricultural Land Use 32 %
Forested Land Use 67 %


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

Physical Stream Habitat
Instream Habitat 3/20 (Poor)
Epifaunal Substrate 3/20 (Poor)
Velocity/Depth Diversity 4/20 (Poor)
Pool Quality
Pool Extent = 60 meters 		6/20 (Marginal)
Riffle Quality
Riffle Extent = 15 meters 		6/20 (Marginal)
Shading 95 %
Embeddedness 100 %
The embeddedness, a measure of silt on the stream bottom, was 100%. This is very high, and may adversely affect biotic communities.
Several measures of instream habitat were considered 'Poor' at this location.


Stream Water Quality:
Water temperature 18.9 ° C
Dissolved oxygen (DO) 8 mg/L
pH (lab) 6.51
Conductivity 127 µmho/cm
Alkalinity
(acid neutralizing capacity) 		109.7 µeq/L
Dissolved organic carbon (DOC) 1.9547 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 9 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
Eastern Mosquitofish 29
Eastern Mudminnow 20
Rosyside Dace 18
Blacknose Dace 14
Creek Chub 14
Least Brook Lamprey 9
Tessellated Darter 7
American Eel 6
Green Sunfish 1
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
Common Five-Lined Skink
Northern Green Frog
Northern Two-Lined Salamander
Pickerel Frog

Crayfish:
No crayfish noted.

Exotic Plants:
Japanese Stiltgrass
 

Benthic Macroinvertebrates:
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Genus/Family Common Name Count
Micropsectra Non-Biting Midges 18
Tanytarsus Non-Biting Midges 10
Ablabesmyia Non-Biting Midge 9
Paratendipes European Non-Biting Midge 8
Acerpenna Tiny Blue-Winged Olive Mayflies 8
Thienemannimyia group Non-Biting Midges 7
Trissopelopia Non-Biting Midges 3
Rheosmittia Non-Biting Midges 3
Stempellinella Non-Biting Midges 3
Calopteryx Damselfly 3
Parametriocnemus Non-Biting Midges 3
Corynoneura Non-Biting Midges 3
Musculium Fingernail Clam 2
Tanypodinae Non-Biting Midges 2
Polypedilum Non-Biting Midges 2
Ironoquia Northern Caddisfly 2
Amphipoda Scud 2
Amphinemura Spring Stonefly 1
Dytiscidae Predaceous Diving Beetle 1
Hydroporus Water Beetle 1
Thienemanniella Non-Biting Midges 1
Tvetenia Non-Biting Midges 1
Tribelos Non-Biting Midges 1
Eurylophella Mayfly 1
Nigronia Megaloptera (Dark Fishfly) 1
Lype Net Tube Caddisfly 1
Isotomurus Elongate-Bodied Springtail 1
Gammarus Amphipod 1
Anchytarsus Beetle 1
Pseudolimnophila Crane Fly 1
Dicrotendipes Non-Biting Midges 1
Diplocladius Non-Biting Midges 1
Paraphaenocladius Non-Biting Midges 1
Parachaetocladius Non-Biting Midge 1
Paracladopelma Non-Biting Midge 1
Procladius Non-Biting Midge 1
Chaetocladius Non-Biting Midges 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.