ON-LINE VERSION
A DATA SET is a series of observations collected by the same methodology. Each data set should have documentation sufficient for someone unfamiliar with the research to replicate the study. Data sets may be broken into subsets (data files) that are discrete in space and time, in that order. The documentation for a data set should include all spatial and temporal subdivisions of the data.
NOTES:
| PERSON(S) COMPLETING THIS FORM: | E-MAIL ADDRESS: |
| Juan Felipe Blanco L. | jblanco@lternet.edu |
DATA SET IDENTIFIER : Neritina snailsrsponses to channel realignment
PROJECT TITLE : Physical habitat, disturbances, and the population ecology of the migratory snail Neritina virginea (Gastropoda: Neritidae) in streams of Puerto Rico (Community Ecology of Streams Snails)
PROJECT DESCRIPTION : Diadromous fauna, migrating between marine and coastal streams is dominant in the neotropics. However, the factors controlling their population distribution and size are poorly understood. The migratory snail Neritina virginea (Gastropoda: Neritidae), abundant in estuaries and coastal rivers in the Caribbean, was studied to understand those factors. The objectives of the study were three-fold: 1) to identify the factors controlling the distribution of diadromous fauna at different spatial scales, 2) to determine patterns and causes of massive upstream migrations and their importance for population persistence, and 3) to integrate this knowledge into conservation strategies for migratory species and stream management plans.
After a survey of 32 coastal streams around Puerto Rico (Greater Antilles), it was evidenced that physical variables operating at different levels of the spatial hierarchy controlled longitudinal distribution of N. virginea. The hierarchically organized variables were river-ocean connectivity (regional scale), instream barriers and water chemistry (stream-network scale), habitat hydraulics (reach scale) and nearbed-flow roughness and depth (habitat scale). However, michohabitat scale distribution depended upon habitat and reach scale context. At habitat scale, water depth in pools, and nearbed flow roughness in riffles were the most important controls. At the reach scale, spatial heterogeneity among and within streambed patches was related to flow refugia, therefore controlling sensitivity of N. virginea density to flooding disturbances.
In addition, the role of structures (bridges) and maintenance activities (downstream channel realignment) associated to road crossings over streams was assessed. By splitting the stream channel and deflecting the flow, bridge pilings altered upstream migration routes. In particular, migratory individuals used more frequently boulder-and-cobble riffle reaches and avoided gravel-bed run reaches. Impact assessment of channel realignment over a 70 m reach in lower Rio Mameyes (NE Puerto Rico) showed that increase in frequency of fine sediment patches contributed to local population depletion and high mortality of juvenile individuals migrating upstream. As a consequence a population located 100 m upstream became isolated and did not recover from a crash caused by a major storm flood occurre after the channel realignment. In conclusion, distribution and size of populations of diadromous fauna such as N. virginea in coastal streams is influenced by hierarchically organized variables. By affecting variables at microhabitat to reach scales, road crossings over streams contribute to reduce longitudinal connectivity, and isolate upstream populations of N. virginea.
LTER CORE AREAS: Annotate all that apply (See online list)
| Population dynamics |
| Disturbance patterns |
LEF LTER 1 RESEARCH TOPIC: (Annotate all that apply) (See online list)
| None |
We define a data file as a component of a data set. A data set can have
only one data file or more. Basically, different data files have different data
structures or format .
DATA
SET FILES (SUBSETS):
| 1 | snail size and density at Mameyes upstream Route 3 (longterm) | long-term_snailSizeDensityMameyesupRoute3.txt | August 22, 2000 | Weekly or monthly | December 5, 2003 |
| 2 | monitoring at Mameyes Upper Golfcourse | monitoringMameyesUpperGolfcourse.txt | August 16, 2002 | Monthly | December 5, 2003 |
| 3 | monitoring at Mameyes downstream Route 3 | monitoringMameyesdownstreamRoute3.txt | August 13, 2002 | Monthly | December 5, 2003 |
| 4 | snail size at Mameyes downstream Route 3 and Upper Golfcourse | snailSizeMameyesandGolfcourse.txt | August 22, 2000 | Weekly or monthly | December 5, 2003 |
| 5 | habitat distribution Mameyes vs Espiritu Santo | habitatDistMameyesvsEspirituSanto.txt | June 10, 2003 | weekly | July 3, 2003 |
RESEARCH LOCATION: Río Mameyes at intersection with PR Route 3 (Municipality boundary between Luquillo and Río Grande) and 200 m upstream near PRASA Water Intake. Río Espíritu at Sector La Curvita Santo located 500 m upstream from PRASA dam.
Juan Felipe Blanco L. |
| Frederick N. Scatena | fns@sas.upenn.edu |
| Juan Felipe Blanco L. | +57-4-210 5620 | jblanco@lternet.edu |
SOURCE OF FUNDING (SPONSOR): IITF-USDA Forest Service, LTER, PR-LSAMP, El Verde REU Program
DATA SET ABSTRACT: This data set includes N. virginea densities and sizes relative to streambed substrate type, water depth, and near-bed water velocity in three sites in a low land segment in Río Mameyes near PR Route 3 bridge: 1) 50 m upstream from bridge, 2) immediately downstream from bridge, and 3) 200 m downstream from bridge (upper Westin Riomar Golfcourse). In addition, above variables are reported for pools and riffles located at PRASA Intake (Río Mameyes) and at La Curvita (Río Espíritu Santo).
DATA SET METHODS: Snails were collected, counted, and measured within 0.5 x 0.5 m quadrats placed on the streambed as follow: snails on and under rocks were counted within 0.5 x 0.5 m quadrats (n=10) placed on the streambed on a weekly basis. Sampling quadrats were placed ˜1 m apart across the main channel (MC), and in five pairs along the side channel (SC). At SC, one quadrat of each pair was placed on the thalweg and another on the shallow part. In addition, a random sample of individuals was collected from each quadrat to measure shell size. Shell size was measured as aperture width (straight line running along the columnella from the base of the operculum to the shell shoulder on body whorl). Total length (TL, perpendicular to AW) is related to aperture width (AW) but cannot be measured in individuals with broken outer lips (TL=1.24AW+0.04, r2=0.98).
Three sampling sites (reaches) in Río Mameyes near Route 3 Bridge were weekly to monthly sampled between August 2000 and December 2003.
Near-bed water velocity was measured at 2 cm above the streambed using a Marsh-McBirney flowmeter. Each velocity measurement was averaged over 30 s and 3 to 5 measurements were made at each point. Ten points every 1 m were sampled across MC. Paired sampling points (thalweg vs. shallow) were measured in five cross sections along SC.
Four habitats (point-bar and straight channel pools, a riffle, and a high flow pond) in Río Mameyes near Route 3 Bridge were weekly sampled between August and December 2000. Water depth and substrate type were measured within each quadrat. The three-most abundant substrates were classified as boulders, cobbles, pebbles, gravel or sand/fines. Plots covered >1/3 by Elodea were classified as “mats”. Nearbed water velocity was measured along cross-sections within each habitat as described in the data set "Neritina snails upstream migrations"..
Discharge regime descriptors were calculated using data from USGS gage 50066000 located 50 m upstream of Route 3 bridge.
Pyron, M., and A. P. Covich. 2003. Migration patterns, densities and growth of Neritina punctulata snails in Río Espíritu Santo and Río Mameyes, Northeastern Puerto Rico. Caribbean Journal of Science 39:338-347.
Blanco, J. F. 2005. Physical habitat, disturbances, and the population ecology of the migratory snail Neritina virginea (Gastropoda: Neritidae) in streams of Puerto Rico. Ph. D. Dissertation, University of Puerto Rico, Rio Piedras Campus, Department of Biology. 250 p.
Blanco, J. F. and F. N. Scatena. 2006. Hierarchical contribution of river–ocean connectivity, water chemistry, hydraulics, and substrate to the distribution of diadromous snails in Puerto Rican streams Journal of the North American Benthological Society, 25 (1):xxx-xxx
Blanco, J. F. and F. N. Scatena. 2005. Floods, Habitat Hydraulics and Upstream Migration of Neritina virginea (Gastropoda: Neritidae) in Northeastern Puerto Rico. Caribbean Journal of Science, 41: 55-74
Statzner B., Gore J.A. & Resh V.H. (1988) Hydraulic stream ecology: observed patterns and potential applications. Journal of the North American Benthological Society, 7, 307-360
CROSS-REFERENCES
(other data sets related to this one): LTERDBAS #141: Neritina snails hierarchical distribution; LTERDBAS #140: Neritina snails upstream migrations; LTERDBAS # 151: Neritina snails rsponses to channel realignment
SAMPLE
LOCATION: NA
STORAGE SITES(of data files): ITES
INVESTIGATOR'S ASSIGNED KEYWORDS: Neritina virginea, amphidromous fauna, lotic populations, spatial heterogeneity, hydromodifications; human disturbances; habitat complexity; streambed roughness; hydraulics; tropical streams, Puerto Rico
LEF LTER OFFICIAL KEYWORDS (See table): Q. Mameyes, river, road, discharge, population dynamics, environmental variables, human, aquatic gastropods (mollusks), dissertation, peer reviewed journal
PUBLICATIONS:
Blanco, J. F., and F. N. Scatena. 2005. Floods, Habitat Hydraulics and Upstream Migration of Neritina virginea (Gastropoda: Neritidae) in Northeastern Puerto Rico. Caribbean Journal of Science 41:55-74 (Abstract)
RESTRICTED ___ UNRESTRICTED __X_
REASONS TO RESTRICT DATA IN THIS DATA SET BEYOND ITS TWO YEAR POLICY PERIOD*:
*WILL HAVE TO BE APPROVED BY AT LEAST ONE LUQ LTER PRINCIPAL INVESTIGATORS: N. Brokaw, J. ZIMMERMAN, A. LUGO
__X_ "File" copy only:Data Management will only file an electronic
copy of the data file and its documentation
___ " Enter" data on-line:Data Management will be in charge
of entering the data on computer files (Contact Eda
C. Meléndez)
Geographical positional system (GPS) Coordinates for each location:
| location | latitude | longitude |
| Río Mameyes at intersection with road PR Route 3 (bridge 1771). | 18°22’27”N | 65°45’50” W |
|
File Name or # above (all in which the variable appears) |
1 | 1, 3 | 1 | 1, 2, 3 | 1, 2, 3, 5 | 2, 3, 4, 5 |
|
AbbreviationAbbreviation(as it appears on the data file) |
sizeDate | size_mm | densityDate | stageLevel_ft | snailDensity_ind.-m2 | date |
| Date | Shell, snail or individual size | Date | Stage level | Snail density | Date of sampling | |
| Date in which snail sampled was measured (mm/dd/yy) | Measurement of Shell, snail or individual size, measured as aperture width | Date in which snail density was calculated (mm/dd/yy) | Stage level at USGS gage 50066000 | Number of individual snails per m2 | Date when sampling was performed (mm/dd/yy) | |
| millimeter | foot | numberPerMeterSquared | ||||
| 0.05 | 0.02 | |||||
| 8/22/2000 - 5/12/2002 | 1.4, ..., 20.8 | 8/22/2000, 5/12/2002 | 0,… | 0,… | 8/22/2000, 5/12/2002 | |
| decimal | decimal | decimal | ||||
VARIABLES (ATTRIBUTES):
File Name or # above (all in which the variable appears) |
2, 3, 5 | 2, 3 | 2, 3, 5 | 2, 3, 5 | 4 |
AbbreviationAbbreviation(as it appears on the data file) |
substrates | Kv_cm | waterDepth_cm | meanWaterVelocity_cm-s | site |
| Dominant substrates | Streambed Roughness coefficient | Water depth | Mean water velocity | Sampling site | |
| Three-most abundant substrate categories | Height of streambed roughness elements (i.e. rocks) separating nearbed flow | Water depth | Nearbed water velocity (measured 2 cm above streambed) | Sampling site in lower Río Mameyes | |
| centimeter | centimeter | centimetersPerSecond | |||
| 0.1 | |||||
| B = boulders; diameter greater than 256 mm, C = cobbles from 256 to 64 mm, P = pebbles from 84 to 16 mm, G = gravel and finer less than 16 mm, M = Elodea mats | 0.6, 3.4 | 0, … | 0, … | Downstream Route 3, Upper Golfcourse reference reach | |
| alphabetical | decimal | decimal | decimal | alphabetical | |
VARIABLES (ATTRIBUTES):
File Name or # above (all in which the variable appears) |
4 | 5 | 5 | 5 |
AbbreviationAbbreviation(as it appears on the data file) |
downstreamRoute3ChanType | riverName | habitat | meanSnailSize_mm |
| Downstream Route 3 Channel Type | Name of River | Habitat Type | Average snail individual size | |
| Channels located downstream from Route 3 at Río Mameyes before and after channel realignment | Name of the river where samples where collected | Channel unit with distinctive hydraulics and morphology at a scale of 101 m2 | Mean measurement of snail individual size, measured as aperture width | |
| millimeter | ||||
| 0.05 | ||||
| Former main channel, Former size channel, New realigned | Mameyes, Espiritu Santo | Pool, Riffle | 1.4,.., 20.8 | |
| alphabetical | alphabetical | alphabetical | decimal | |
COMPUTATIONAL METHODS:
FOR DATA MANAGER USE ONLY
DATE OF LAST REVIEW: March 6, 2009
DATE OF LAST ENTRY: December 5, 2003
STAGE OF DATA SET MANAGEMENT (dates):
RECEIVED: December 23, 2005 (deferred for 2 years)
ENTERED: December 23, 2005
FILED ON-LINE: July 20, 2007
REVIEWED BY RESEARCHER:
FILING MEDIA:
NAME OF DOCUMENTATION FILE: Neritina snails impacts of stream realignment.doc; lterdb151.htm
NAME OF ON - LINE CATALOG: LTERDBAS
RECORD #: 151
DOCUMENT TYPE: binary only
PRIORITY TO BE ENTERED: N/A
Rev. date of this form: 28 July 200/ 15 July 2001/June 9, 2003/March 16, 2004/12 April 2005/ 8 November 2005/ 16 January 2006