MBSS Site Summary for: PAXL-109-R-2004

Site Photos

Field photo showing stream conditions at site PAXL-109-R-2004-1 (Opens in a new window) Field photo showing stream conditions at site PAXL-109-R-2004-2 (Opens in a new window)

Located on HORSE LANDING CR in the Patuxent River lower watershed, 8-digit code: 02131101.
This stream was visited in the spring on 3/4/2004 and again in the summer on 7/7/2004.

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 - 2.0 / 5.0
Benthic IBI Good - 4.1 / 5.0

Land Use

Land use can provide important information for determining stream health.
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Catchment area 221 acres A stream flowing through a densely forested area. An example of a forested stream.
Urban Land Use 17 %
Agricultural Land Use 41 %
Forested Land Use 42 %


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

Physical Stream Habitat
Instream Habitat 6/20 (Marginal)
Epifaunal Substrate 7/20 (Marginal)
Velocity/Depth Diversity 6/20 (Marginal)
Pool Quality
Pool Extent = 8 meters 		6/20 (Marginal)
Riffle Quality
Riffle Extent = 75 meters 		11/20 (Suboptimal)
Shading 90 %
Embeddedness 100 %
The embeddedness, a measure of silt on the stream bottom, was 100%. This is very high, and may adversely affect biotic communities.


Stream Water Quality:
Water temperature 22.2 ° C
Dissolved oxygen (DO) 8.2 mg/L
pH (lab) 7.62
Conductivity 220 µmho/cm
Alkalinity
(acid neutralizing capacity) 		921.8 µeq/L
Dissolved organic carbon (DOC) 1.6 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 3 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
Eastern Mudminnow 91
Blacknose Dace 59
American Eel 2
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
Northern Green Frog
Northern Spring Peeper
Northern Two-Lined Salamander
Southern Leopard Frog

Crayfish:
No crayfish noted.

Exotic Plants:
Japanese Honeysuckle
Japanese Stiltgrass
 

Benthic Macroinvertebrates:
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Genus/Family Common Name Count
Gammarus Amphipod 52
Anchytarsus Beetle 7
Tipula Crane Fly 6
Ephemerella Sulphur Mayfly 6
Parametriocnemus Non-Biting Midges 5
Pycnopsyche Great Autumn Brown Sedge Caddisfly 4
Nemouridae Nemourid Stonefly 3
Diplectrona Net-Spinning Caddisfly 3
Polypedilum Non-Biting Midges 2
Leptophlebiidae Pronggilled Mayfly 2
Amphinemura Spring Stonefly 2
Prostoia Spring Stonefly 2
Orthocladius Non-Biting Midges 2
Acerpenna Tiny Blue-Winged Olive Mayflies 1
Hemerodromia Tiny Fly 1
Lumbriculidae Worm 1
Rheosmittia Non-Biting Midges 1
Tanytarsini Non-Biting Midges 1
Zavrelimyia Non-Biting Midges 1
Limnephilidae Northern Casemaker Caddisfly 1
Chironomini Non-Biting Midge 1
Micropsectra Non-Biting Midges 1
Clioperla Green-Winged Stonefly 1
Caecidotea Isopod 1
Nigronia Megaloptera (Dark Fishfly) 1
Calopteryx Damselfly 1
Stenonema Flatheaded Mayfly 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.