1990s bird and vegetation data from UMR floodplain forest

From 1994-1997 I surveyed breeding birds and sampled vegetation at 391 random points on UMR floodplain forest along a latitudinal gradient to characterize bird assemblages and associations with gradients in forest structure at the local survey point and land cover composition within 200m radius of survey points (landscape scale). We conducted 10 minute 50m fixed radius point counts (Ralph et al. 1993) to survey birds during the breeding period between 30 May and 10 July in all years. We sampled the southernmost pool (13) first and then progressed to each pool in succession northward, finishing in Pool 4, sampling each point once a season. Surveys were conducted from 30 minutes before to five hours after local sunrise. We recorded all birds seen and heard within a ten-minute sampling period and mapped locations data sheets within and beyond 50m from the observer (as determined by visual estimation). We recorded vegetation cover using a releve (Mueller-Dombois and Ellenberg 1974) within a 10m radius surrounding the survey point immediately following each bird survey. We estimated cover classes (less than5%, 5-25%, 26-50%, 51-75%, 76-100%) for vegetation in four vertical layers (canopy, subcanopy, understory, ground), as well as litter cover and depth, or water cover and depth if the area was partially flooded. Heights of these layers differed among different sites and not all layers were present at all sites. We noted the three tree species with the most cover in the canopy and subcanopy each. We estimated canopy and subcanopy height (m) using a clinometer, and visually estimated understory and ground layer height (m). We estimated litter depth (cm) by taking the average of three readings from the ground to the top of the litter layer using a ruler. Beginning in 1995 the number of standing snags (greater than 10cm dbh) within the 50m radius were counted as seen from center of the survey circle. Within 200m buffers of each sample point, I estimated the area (m2) of forest, wet meadow, dry grassland, emergent wetland, shrub carr, urban, agricultural, and open water habitats, and lengths of edges between these habitats (m) extracted from 1:15,000 scale GIS coverages based on 1989 color infrared aerial photos of study pools using ARC/INFO.