Data frames containing metadata for each spatial classification at which ecological context data are derived in LAGOSNE. The spatial classifications include 100m buffers (buffer100m), 500m buffers (buffer500m), interlake watersheds (iws), hydrologic units (hu12, hu8, hu4), ecological drainage units (edu), counties (county), and states (state). Each abbreviation is the name of the data frame, with all or a subset of the following variables. For more information about derivation of each spatial classification, see Details below or Additional file 7 from doi:10.1186/s13742-015-0067-4 .
Format
Data frames with all or a subset of the following variables. Number of observations is equal to the number of zones in each spatial classification (see Details below).
*_nhdid: permanent lake-specific identifier from the National Hydrography Dataset (* = buffer100m, buffer500m, iws)
*_name: text name of the zone (* = iws, hu12, hu8, hu4, county, state)
hu*: unique zone identifier (* = 12, 8, 4)
*_ha: area of spatial classification in hectares (* = buffer100m, buffer500m, hu12, hu8, hu4, edu, county)
*_areaha: area of spatial classification in hectares (* = iws, )
*_perimkm: perimeter of spatial classification in kilometers (* = iws, )
*_lat: latitude of centroid of polygon in decimal degrees (NAD83) (* = iws, hu12, hu8, hu4, edu, county, state)
*_long: longitude of centroid of polygon in decimal degrees (NAD83) (* = iws, hu12, hu8, hu4, edu, county, state)
*_lakeareaha: lake area (ha) of focal lake associated with polygon (* = iws, )
*_country: whether the polygon lies within the US ("US") or the US and Canada (US_CA) (* = hu12, edu)
*_pct_in_usa: percent of polygon within the US boundary (* = iws, hu12, edu)
*_ha_in_usa: area (ha) of polygon within the US boundary (* = iws, hu12, edu)
*_pct_in_nwi: percent of polygon within the USFWS National Wetland Inventory (NWI) boundary (* = hu12, hu8, hu4, edu, county, state)
*_ha_in_nwi: area (ha) of polygon within the USFWS National Wetland Inventory (NWI) boundary (* = hu12, hu8, hu4, edu, county, state)
*_zoneid: a unique identifier for each IWS in LAGOSNE, numbered 1:n with classification prefix (e.g., HU12_1) (* = iws, hu12, hu8, hu4, edu, county, state)
lagoslakeid: LAGOSNE unique identifier for focal lake
hu4_states: states that intersect hu4 zone polygon
state: 2-letter state abbreviation
county_state: state where county is located
Details
The nine LAGOSNE spatial classifications were used to summarize the ecological context of each lake. Ecological context themes include land use/land cover (LULC), connectivity (CONN), and climate, hydrology, atmospheric deposition, and groundwater (CHAG). Not all themes were derived at all classifications due to data availability. Briefly:
iws: a dataframe with 51065 observations of 12 variables. The area of land that drains directly into a lake, and into all upstream-connected, permanent streams to that lake exclusive of any upstream lake watersheds for lakes greater than 10 ha that are connected via permanent streams. For details on how the watersheds were delineated, see additional file 8 in Soranno et al. (2015). Themes derived at the iws classification include LULC and CONN.
buffer100m: a dataframe with 51065 of 3 variables. Buffers are a 100 m equidistant buffer of the land that is 100 m from the lake shoreline, calculated using the ArcGIS Buffer tool. Themes derived at the 100m buffer classification include LULC.
buffer500m: a dataframe with 51065 of 3 variables. Buffers are a 500 m equidistant buffer of the land that is 500 m from the lake shoreline, calculated using the ArcGIS Buffer tool. Themes derived at the 500m buffer classification include LULC and CONN.
hu12: a dataframe with 20257 observations of 11 variables. The Watershed Boundary Dataset defines boundaries based on surface water drainage and creates nested Hydrologic Units (sometimes abbreviated and referred to as HUCs, which are hydrologic unit codes) that are georeferenced to the USGS 1:24,000 topographic base map. HUC12s are the sixth level of classificiation. HUC12s are defined along natural hydrologic breaks based on land surface and surface-water flow and they have a single flow outlet except in frontal, lake, braided-stream, or closed-basin hydrologic units. Themes derived at the HUC12 classification include LULC, CONN and CHAG.
hu8: a data frame with 511 observations of 9 variables. HUC8s are the fourth level of classificiation. Sometimes called 'watersheds', a HUC8 is a geographic area representing part or all of a surface drainage basin, a combination of drainage basins, or a distinct hydrologic feature. Themes derived at the HUC8 classification include LULC, CONN, and CHAG.
hu4: a data frame with 65 observations of 9 variables. HUC4s are the second level of classification, called a 'subregion'. A subregion includes the area drained by a river system, a reach of a river and its tributaries in that reach, a closed basin(s), or a group of streams forming a coastal drainage area. Themes derived at the HUC4 classification include LULC, CONN, and CHAG.
edu: a data frame with 91 observations of 10 variables. Ecological drainage units (EDUs) follow the WBD boundaries, and are of roughly similar size to HUC6s. EDUs were delineated by grouping the HUC8 watersheds based on common zoogeographic history, and physiographic and climatic characteristics. Themes derived at the EDU classification include LULC, CONN, and CHAG.
county: a data frame with 955 observations of 8 variables. Counties (political boundary) within the 17-state region of LAGOSNE. Themes derived at the county classification include LULC, CONN, and CHAG.
state: a dataframe with 17 observations of 7 variables. Themes derived at the state classification include LULC, CONN, and CHAG.
References
Soranno et al. (2017) doi:10.1093/gigascience/gix101