MBSS Site Summary for: PAXM-103-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 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 Fair - 3.7 / 5.0
Benthic IBI Good - 5.0 / 5.0

Land Use

Land use can provide important information for determining stream health.
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Catchment area 532 acres A stream flowing through a densely forested area. An example of a forested stream.
Urban Land Use 1 %
Agricultural Land Use 36 %
Forested Land Use 63 %


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

Physical Stream Habitat
Instream Habitat 10/20 (Marginal)
Epifaunal Substrate 11/20 (Suboptimal)
Velocity/Depth Diversity 6/20 (Marginal)
Pool Quality
Pool Extent = 54 meters 		13/20 (Suboptimal)
Riffle Quality
Riffle Extent = 21 meters 		6/20 (Marginal)
Shading 92 %
Embeddedness 45 %


Stream Water Quality:
Water temperature 17.1 ° C
Dissolved oxygen (DO) 7.8 mg/L
pH (lab) 6.61
Conductivity 133 µmho/cm
Alkalinity
(acid neutralizing capacity) 		118.7 µeq/L
Dissolved organic carbon (DOC) 1.815 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 7 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
Rosyside Dace 123
Blacknose Dace 71
Creek Chub 39
American Eel 10
Least Brook Lamprey 8
Eastern Mudminnow 7
Green Sunfish 3
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
Fowler's Toad
Gray Treefrog
Northern Green Frog
Northern Two-Lined Salamander
Pickerel Frog
Southern Leopard Frog
Wood Frog

Crayfish:
No crayfish noted.

Exotic Plants:
Canada Thistle
Japanese Honeysuckle
Japanese Stiltgrass
Mile-A-Minute
 

Benthic Macroinvertebrates:
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Genus/Family Common Name Count
Tanytarsus Non-Biting Midges 26
Acerpenna Tiny Blue-Winged Olive Mayflies 22
Haploperla Green Stonefly 9
Micropsectra Non-Biting Midges 7
Orthocladius Non-Biting Midges 6
Parametriocnemus Non-Biting Midges 4
Rheosmittia Non-Biting Midges 4
Thienemannimyia group Non-Biting Midges 4
Tvetenia Non-Biting Midges 3
Gammarus Amphipod 3
Amphinemura Spring Stonefly 3
Hydropsyche Net-Spinning Caddisfly 2
Hexatoma Crane Fly 2
Anchytarsus Beetle 2
Lepidostoma Little Brown Sedge Caddisfly 2
Eurylophella Mayfly 2
Zavrelimyia Non-Biting Midges 2
Macronychus Riffle Beetle 1
Nigronia Megaloptera (Dark Fishfly) 1
Diplectrona Net-Spinning Caddisfly 1
Stenelmis Beetle 1
Simulium Black Fly 1
Neophylax Caddisfly 1
Pseudolimnophila Crane Fly 1
Chrysops Deerfly 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.