2024 Double Headshot Islands Vascular Plant Botanical Inventory

2024 Double Headshot Islands Vascular Plant Botanical Inventory Cutler, Maine, United States.DOUBLE SHOT ISLAND (CIR 79-351)OUTER DOUBLE SHOT ISLAND (CIR 79-352) The Double Headshot Islands is a remote pair of islands located 7 km southwest of Cutler, Maine. The island was accessed via the boat launch near Machiasport. Inventory Conducted: We conducted 6 days of field work on the Double Headshot Islands during the 2024 season: 22 June, 3, 8 July, and 7, 16, and 26 August. Maine Natural History ObservatoryLead Botanist: Glen MittelhauserContact: [e-mail] Sources: Maine Coastal Islands National Wildlife Refuge -----------------------------Permissions and Data Use These data are made publicly available to encourage transparency, long-term preservation, and reuse in ecological research, conservation planning, and education. These inventories represent baseline conditions at the time of survey and should be interpreted with appropriate consideration of survey year, methods, and observer effort. Users are welcome to download, analyze, and incorporate these data into derivative works, including independent analyses and publications. Any use of these data must acknowledge the original source by citing the website where the data are archived and giving credit for the historical data to Glen Mittelhauser, Maine Natural History Observatory. Users are encouraged, though not required, to notify Maine Natural History Observatory of substantial or interpretive uses of the dataset, particularly those leading to publication. -----------------------------File list and description of each file(See report for more information) 1) Core fileFile Name: DoubleHeadShotIslands2024_EventCore_GridCells.csv Description: A virtual 25x25 m grid was constructed using GIS software, spanning both terrestrial and intertidal zones, resulting in over 500 grid cells, although many of these incorporate open water between the islands. The grid was oriented following true compass bearings, with the UTM coordinates (NAD83, Zone 19) of the grid extent being 4941000, 637550; 4940300, 638000. This file contains coordinates only for the grid cells that contained vascular plants. GRID CELLS2) Extension of Core fileFile Name: DoubleHeadShotIslands2024_Occurrences_GridCells.csv Connects to: DoubleHeadShotIslands2024_EventCore_GridCells.csv linked using the gridCell column. Description: During field visits in early, mid, and late seasons, we recorded vascular plant species presence and estimated their categorical abundance within each grid cell. Abundance categories were defined as follows:Common: Species widely distributed, occurring in large numbers (>40% cover).Occasional: Species scattered, typically 15-40% cover.Uncommon: Species not widely distributed, typically 2-15% cover.Rare: Species restricted to small areas or specialized habitats, typically <1% cover. QUADRATS (GRID CELLS)3) Extension of Core fileFile Name: DoubleHeadShotIslands2024_Quadrats_GridCells.csv Connects to: DoubleHeadShotIslands2024_EventCore_GridCells.csv linked using the gridCell column. Description: To assess species cover in the island's interior, we selected 32 grid cells containing vascular plants in the interior of the island. Within each selected grid cell, three 1x1 m quadrats were placed approximately 2 meters from the grid cell center (estimated using GPS). Each quadrat's placement was adjusted systematically: one quadrat ~2 meters to the north, another quadrat ~2 meters to the southeast, and the third quadrat ~2 meters to the southwest. If vegetation at the quadrat location was trampled, the quadrat was relocated slightly further from the center. Each quadrat was sampled non-destructively for visual estimates of vascular plant cover. Cover estimates for species were made without rounding to categories or nearest percentages, ensuring accuracy. Calibration templates (e.g., 1%, 2.5%, and 5% cover) and transparent templates for smaller fractions (0.1%-1%) were used for precision. Separate cover estimates were recorded for non-plant categories, including rock, moss, and bare soil. FOREST PLOTS (CANOPY MEASURMENTS)3) Extension of Core fileFile Name: DoubleHeadShotIslands2024_ForestPlots_Canopy.csv Connects to: DoubleHeadShotIslands2024_EventCore_GridCells.csv linked using the gridCell column. Description: Forested grid cells were selected a priori from aerial imagery, ensuring an approximately even distribution across the island(s). The default corner (northeast, northwest, southeast, or southwest) was randomly chosen for sampling each day (Figure 2). If the pre-assigned corner was not representative of the surrounding forest—such as when a sample intended for forest interior fell on a forest edge or meadow—the sample site was adjusted by moving clockwise (northeast, southeast, southwest, northwest) to a more appropriate location. Once the corner of the grid cell was located using a handheld GPS unit, a 10 × 10 m perimeter was established, extending toward the center of the pre-selected grid cell. Canopy cover measurements were taken at the north, south, east, and west corners, as well as at the plot center, using a spherical densiometer. Plot number is the grid cell number and the corner of the grid cell the plot is located on. The plot extends from that corner into the plot it is located in (10m on a side). canSW = the four densiometer measurements taken at the SW corner of the 10m2 plot, canNE = NE corner, … , canC = plot center. Values reported are the raw densiometer reading, not converted to percentages. FOREST PLOTS (WOODY PLANT STEM MEASUREMENTS)4) Extension of Core fileFile Name: DoubleHeadShotIslands2024_ForestPlots_Stems.csv Connects to: DoubleHeadShotIslands2024_EventCore_GridCells.csv linked using the gridCell column. Description: Woody plant stem measurements were recorded after the forest plot was established and canopy measurements were completed. All stems with a diameter at breast height (DBH) ≥2.5 cm within the 10 × 10 m plot were measured. Stems branching below the standard breast height (1.37 m) were treated as separate individuals for data collection purposes. FOREST PLOTS (QUADRATS)5) Extension of Core fileFile Name: DoubleHeadShotIslands2024_ForestPlots_Quadrats.csv Connects to: DoubleHeadShotIslands2024_EventCore_GridCells.csv linked using the gridCell column. Description: From the forest plot center, three 1 × 1 m quadrats were placed two meters to the north, southeast, and southwest, respectively, following the orientation shown in Figure 1. Within each quadrat, all vascular plant species were identified, and their percent cover was estimated. The percent cover of bare ground and debris within each quadrat was also recorded. Quadrats are placed 2m from plot center, one to the N, SE, & SW. -----------------------------Column Definitions Name: gridCell Type: IntegerDescription: Identifier for the 25x25 m grid cells.Maps to term(s) in Darwin Core: eventID (http://rs.tdwg.org/dwc/terms/eventID) Name: verbatimCoordinateSystem Type: StringDescription: The coordinate format for the location.Maps to term(s) in Darwin Core: verbatimCoordinateSystem (http://rs.tdwg.org/dwc/terms/verbatimCoordinateSystem) Name: UTMx(Easting) Type: DoubleDescription: UTM X coordinate.Maps to term(s) in Darwin Core: Name: UTMy(Northing) Type: DoubleDescription: UTM Y coordinate.Maps to term(s) in Darwin Core: Name: geodeticDatum Type: StringDescription: The geodetic datum upon which the geographic coordinates given are based.Maps to term(s) in Darwin Core: geodeticDatum (http://rs.tdwg.org/dwc/terms/geodeticDatum) Name: UTMZone Type: StringDescription: Maps to term(s) in Darwin Core: Name: year Type: IntegerDescription: The four-digit year in which the survey occurred.Maps to term(s) in Darwin Core: year (http://rs.tdwg.org/dwc/terms/year) Name: samplingProtocol Type: StringDescription: The names of, references to, or descriptions of the methods or protocols of event.Maps to term(s) in Darwin Core: samplingProtocol (http://rs.tdwg.org/dwc/terms/samplingProtocol) Name: island Type: StringDescription: The name of the island on which the location occurs.Maps to term(s) in Darwin Core: island (http://rs.tdwg.org/dwc/terms/island) Name: scientificName Type: StringDescription: The full scientific name, with authorship and date information if known. All nomenclature follows Haines (2011).Maps to term(s) in Darwin Core: scientificName (http://rs.tdwg.org/dwc/terms/scientificName) Name: family Type: StringDescription: The full scientific name of the family in which the Taxon is classified.Maps to term(s) in Darwin Core: family (http://rs.tdwg.org/dwc/terms/family) Name: vernacularNameType: StringDescription: A common or vernacular name.Maps to term(s) in Darwin Core: vernacularName (http://rs.tdwg.org/dwc/terms/vernacularName) Name: statusInMaineType: StringDescription: Native = Considered native to Maine; Exotic = considered non-native to Maine.Maps to term(s) in Darwin Core: Name: measurementTypeType: StringDescription: The nature of the measurement, fact, characteristic, or assertion.Maps to term(s) in Darwin Core: measurementType (http://rs.tdwg.org/dwc/terms/measurementType) Name: measurementValueAbundanceType: StringDescription: C = Common: Species widely distributed, occurring in large numbers (>40% cover).O = Occasional: Species scattered, typically 15-40% cover.U = Uncommon: Species not widely distributed, typically 2-15% cover.R = Rare: Species restricted to small areas or specialized habitats, typically <1% cover.Maps to term(s) in Darwin Core: measurementValue (http://rs.tdwg.org/dwc/terms/measurementValue) Name: gridCellQuadratNumberType: StringDescription: Identifier for the 1x1 m quadrats.Maps to term(s) in Darwin Core: eventID (http://rs.tdwg.org/dwc/terms/eventID) Name: directionType: StringDescription: Cardinal directions.Maps to term(s) in Darwin Core: Name: eventDateType: DateDescription: The date-time or interval during which a Event occurred.Maps to term(s) in Darwin Core: eventDate (http://rs.tdwg.org/dwc/terms/eventDate) Name: measurementValuePercentageType: DecimalDescription: Visual estimates of percentage cover for each species, with separate categories recorded for rock, dead vegetation, bare soil, and washed up debris near the shore. Maps to term(s) in Darwin Core: measurementValue (http://rs.tdwg.org/dwc/terms/measurementValue) Name: forestPlotType: StringDescription: Identifier for the 10 × 10 m forest plot. Plot number is the grid cell number and the corner of the grid cell the plot is located on. The plot extends from that corner into the plot it is located in (10m on a side).Maps to term(s) in Darwin Core: eventID (http://rs.tdwg.org/dwc/terms/eventID) Name: canopyNEType: IntegerDescription: Densiometer reading for Northeast corner of the forestPlot.Maps to term(s) in Darwin Core: Name: canopySEType: IntegerDescription: Densiometer reading for Southeast corner of the forestPlot.Maps to term(s) in Darwin Core: Name: canopySWType: IntegerDescription: Densiometer reading for Southwest corner of the forestPlot.Maps to term(s) in Darwin Core: Name: canopyNWType: IntegerDescription: Densiometer reading for Northwest corner of the forestPlot.Maps to term(s) in Darwin Core: Name: canopyCenterType: IntegerDescription: Densiometer reading for center of the forestPlot.Maps to term(s) in Darwin Core: Name: measurementValueDBHType: DoubleDescription: Stems branching below the standard breast height (1.37 m) were treated as separate individuals for data collection purposes.Maps to term(s) in Darwin Core: Name: fieldNotesType: StringDescription: Notes taken in the field.Maps to term(s) in Darwin Core: fieldNotes (http://rs.tdwg.org/dwc/iri/fieldNotes) Name: forestQuadratDirectionType: StringDescription: Direction of quadrat from forest plot center.Maps to term(s) in Darwin Core: -----------------------------File type information .csv files:- linesTerminatedBy: \n- fieldsTerminatedBy: ;- dateFormat: mm/dd/yyyy -----------------------------Coordinate System A virtual 25x25 m grid was constructed using GIS software, spanning both terrestrial and intertidal zones, resulting in over 500 grid cells, although many of these incorporate open water between the islands. The grid was oriented following true compass bearings, with the UTM coordinates (NAD83, Zone 19) of the grid extent being 4941000, 637550; 4940300, 638000. -----------------------------Citation instructions Author: Glen Mittelhauser, Maine Natural History ObservatoryTitle: 2024 Double Headshot Islands Vascular Plant Botanical InventoryYear of publication: 2024----------------------------- Licensing: CC-BY