Proceedings of the Third International Conference on Invasive ...

<strong>Proceedings</strong> <strong>of</strong> <strong>the</strong> <strong>Third</strong> <strong>International</strong> <strong>Conference</strong> on Invasive SpartinaChapter 2: Spartina Distribution and Spreadentry unit (Trimble Geo-Explorer III).Plant data were entered into <strong>the</strong> unit aspoints, lines or polygons depending on<strong>the</strong> extent <strong>of</strong> <strong>the</strong> invasion. The GPSunits automatically collect data ondate, time, location, area and polygonperimeter and line length. Field staffmanually entered site name, speciesidentification, clone identification,clone diameter, line width, samplename, percent cover class, o<strong>the</strong>rapplicable data and comments.GPS data were downloaded usingPathfinder s<strong>of</strong>tware, exported toArcView, differentially corrected,and reviewed for errors. The data were<strong>the</strong>n exported to Excel and onceagain reviewed for data entry errors.Final data were summarized andmapped in ArcView and statisticallyanalyzed using SYSTAT.Three <strong>of</strong> <strong>the</strong> four non-native taxa<strong>of</strong> Spartina found in <strong>the</strong> San FranciscoEstuary—S. Alterniflora hybrids, S.densiflora, and S. patens—weremapped in 2003. The one locationwhere S. anglica was found in 2001was not included in <strong>the</strong> 2003monitoring program. Spartina specieswere identified in <strong>the</strong> field using plantmorphology (Zaremba 2001). Leafsamples were collected for geneticanalysis to confirm field identifications<strong>of</strong> S. alterniflora and hybrids.Aerial Photo InterpretationIn addition to field-collected data,aerial photo interpretation was used atfive <strong>of</strong> <strong>the</strong> 28 sites for large Spartinahybrid infestations, not single clones.Color infrared photos were taken at1:6000 feet scale at low tide during <strong>the</strong> peak <strong>of</strong> <strong>the</strong> growingseason between August-October when <strong>the</strong> plants were stillgreen to allow for accurate yearly comparison. Photos werescanned at 1200 dpi and orthorectified <strong>the</strong>n imported intoArcView 3.3 for review and analysis. Polygons weredigitized around <strong>the</strong> Spartina meadows and polygons weregiven a cover class (