Data Report: Vegetation Survey at Avian Point Count Stations along Pine Flat Road, in northern Sonoma County, California

Transcription

1 Data Report: Vegetation Survey at Avian Point Count Stations along Pine Flat Road, in northern Sonoma County, California Gregory Vose Audubon Canyon Ranch, Cypress Grove Research Center, Marshall., CA ACR Tech. Rpt October 2015, AUDUBON CANYON RANCH P.O. Box 808, Marshall, CA 94940

2 Data Report: Vegetation Survey at Avian Point Count Stations along Pine Flat Road, in northern Sonoma County, California Gregory Vose Audubon Canyon Ranch, Cypress Grove Research Center, Marshall., CA Introduction This project aims to quantify avian habitat structure and composition along an established avian point-count transect in the central Mayacamas Mountains outside Healdsburg, CA. The surveys were conducted from 8 July through 10 July, 2014, on Pine Flat Road in the central Mayacamas Mountains in Sonoma County, part of which passes through the Audubon Canyon Ranch (ACR) Modini/Mayacamas Preserves (Figure 1). This study, along with recent efforts by the Sonoma County Vegetation Mapping Project (sonomavegmap.org) and avian point-count data collected by ACR, will be used to assess avian habitat values in the central Mayacamas Mountains region. Methods David Self (ACR) collaborated on the field work. Measurements were recorded for 400m and 50m fixed-radius plots, centered on 16 point count stations used for the Pine Flat Road avian monitoring program (Figure 1). Radius measurements excluded the paved road, but included dirt pullouts, collapsing the landscape to generate data that are more representative of the surrounding vegetation. At the 400m scale, we recorded percent area visible and identified vegetation alliances 1, estimating their percent cover of visible area. At the 50m scale, we estimated maximum and median heights for tree (>5m), shrub (0.5-5m), and ground-cover (0-2m) foliage canopy. Overlap between shrub and ground cover classes was differentiated by plant structure. We recorded the presence or absence of fire associated evidence of the most recent (2004) fire. We counted special features including rock outcrops, near vertical slopes, open water, running streams, springs/seeps, fallen logs (>30cm diameter at largest diameter, standing snags (>20cm dbh), cattle troughs, bird nests/boxes, and slash piles. We used the point-intercept method to examine habitat structure, determining percent cover of canopy level, shrub level, and ground level foliage, bare ground, leaf litter, duff layer, dead wood (0-0.5m about ground), and dead wood (0.5-3m above ground). 50m transects were drawn at cardinal directions from each point count station center and point intercept data was taken at 5m intervals, excluding the center (40 pts/station). Cover for the 3 dominant species (>=10% cover) at each of the three structural levels were ranked and estimated. Vegetation densities were measured using the point centered quarter method, with a 50m distance limit and quarters divided using cardinal directions as boundaries. In each quarter we recorded the species/target and its distance from the point for: the closest large tree (>30cm dbh), small tree (10-30cm dbh), sapling (3-10cm) and shrub (>1m), the closest of each of three dominant tree species (tree species were further

3 broken down by size, >50cm dbh and 10-50cm dbh), the closest of each of three dominant shrub species, and the closest slash pile. Calculations. Point intercept hit proportions were calculated to estimate percent cover at each structural level. Tree and shrub densities were estimated using point quarter formulations: Absolute Density = 1 r 2 where r is the mean distance (m) from the center point to the nearest plant in each quarter (Mitchell 2010). Absolute densities were multiplied by 10,000 to convert units to hectares. In cases where no plant was present in the quarter inside our 50m distance limit, we applied a correction factor to avoid over estimating absolute density (Ward and Petranka 1981). Literature cited Sawyer, J. O., T. Keeler-Wolf, and J. M. Evens, A Manual of California Vegetation. Sacramento: California Native Plant Society Press. p Mitchell, K., Quantitative Analysis by the Point-Centered Quarter Method, Ward, W., and Petranka, J., A Correction Factor Table for Missing Point-Center Quarter Data. Ecology, 62(2) Baldwin, G., D. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. Wilken (Eds) The Jepson Manual: Vascular Plants of California, Second Edition Thoroughly Revised and Expanded. University of California Press, Berkeley, CA.

4 Figure 1. Approximate location of 16 point-count stations along Pine Flat Road. The letter after each station number indicates the road ([L]eft or [R]ight) where the station marker is located with respect to a northbound traveler.

5 % Cover Canopy Shrub Ground Cover Bare Ground Leaf Litter Station Figure 2. Comparison of percent cover at 5 vegetation levels across point count stations.

6 Trees per Hectare Trees > 30cm dbh 100 Trees 10-30cm dbh 50 Saplings Station Figure 3. Comparison of tree density of different sized trees across point count stations.

7 Shrubs per Hectare * 71111* Station *Values exceed axis limits Figure 4. Comparison of shrub density across point count stations.

8 Height (m) Trees Shrubs Ground Cover Station Figure 5. Comparison of estimated median heights of three vegetation classes across point count stations.

9 Percent cover Figure 6. Percent cover at estimated median height for three vegetation classes at each station. Numbers next to each point indicate the representative station.

10 Table 1. Percent cover estimates determined by point-intercept, with 50 m transects at cardinal directions (4 transects/station) and sample points every 5 m (10 points/transect). Percent cover was estimated by dividing the number of hits by the number of points (n=40) and multiplying by 100. Station % Cover Canopy Level % Cover Shrub Level % Cover Ground Level % Cover Bare Ground % Cover Leaf Litter % Cover Duff Layer % Cover Dead Wood 0-0.5m % Cover Dead Wood 0.5-3m n= Mean Median S.D Ci (95%;±) Max Min

11 Table 2. Maximum and Median Heights for Vegetation Levels at tree, shrub, ground cover levels. Max tree height (m) Median tree height (m) Max shrub height (m) Median shrub height (m) Max groundcover height (m) Median groundcover height (m) Station n= Mean Median SD Ci (± 95%) Maximum Minimum

12 Table 3. Point Quarter Determination of Shrub and Tree Density; a correction factor was applied in cases where selected trees or shrubs of a given size were absent within 50 m in a quarter (see text). Station Density of trees>30cm/hectare Density of trees 10-30cm/hectare Density of Saplings/hectare Density of Shrubs/hectare n= Mean Median SD CI (± 95%) Maximum Minimum

13 APPENDIX This appendix includes the following sections: A. Field Protocol B. Raw Data C. Sample Data Sheet D. Author s note regarding associated data files A. Field Protocol Materials Surveyors should work in pairs and bring: point intercept ocular tube, 50m tape, compass, range finder, field guides for plant and vegetation alliance identification: The Jepson Manual (Baldwin et al. 2012) and A Manual of California Vegetation (Sawyer et al. 2009), point count station map book, binoculars, data sheets, writing implements. Site Surveys At each site, locate the orange site marker on the correct side of the road. This will serve as the center of the 50m and 400m radius circles you will be studying. Using the 50m tape and/or range finder, identify a 50m distance from your point to get an idea of what a circle of this size looks like. This will help you establish a good sense for this distance and will ensure accurate distance estimates as you survey each station. If you do not have a range finder or tape measure available, you may also pace out the distance. You should also identify a distance of 400m (about ¼ mile) from the point as this distance will be used when collecting data on vegetation alliances. This may be difficult to do without a range finder, but you may use a car odometer and a straight piece of road to get a visual approximation. 400 meter plots: Begin by identifying vegetation alliances and their respective percent covers (use A Manual of California Vegetation 2009). First, estimate what percent of the 400m radius circle centered on the point is visible. You should include all area that you can see even if you need to move away from the point to see the additional area. Keep in mind there are cases where the remainder of the circle will be visible only after proceeding to the next station. Please adjust your approximations to account for these hidden portions of the circle. In recording the alliances you see, only include alliances that comprise at least 1 acre for upland alliances and 0.5 acres for special assemblages such as small wetlands, riparian, and serpentine. Binoculars may be useful for identifying alliances at a distance. In rare cases identification may need to be done by exploration on foot. However, his can be time consuming and is not recommended unless necessary. Determine what percent of the visible area each alliance constitutes and include it on the data sheet. Your estimates for percent cover should account for all visible area (i.e. your percentages should total 100%).

14 50 meter plots: Next you will take data on the 50m radius circle centered on the point. It is important to note that in this study we are collapsing the landscape on the road, effectively removing the road from our data. To accomplish this, distances in the circle should exclude the road by stepping across it when measuring distances that span the road, continuing your distance measure once you have reached the other side. This should also be done with the center point of the circle. You should mark the point from the nearest location off the road to the point marker. However in some cases the vehicle pullout are very large in which case please include them in your distance measures. Begin by estimating the foliage heights. Ground cover and shrubs are determined by form and size, with ground cover from 0-2m and shrubs from 0.5-5m. Shrubs taller than 5m are counted as trees. For sections B and C you only need to indicate presence of charred wood, which can be done by a quick visual inspection of the site, and the number of each type of special feature. Point intercept, For this portion you will determine various structural components of the site s vegetation using the point intercept method. At 5m intervals, not including the center, along cardinal (N, E, S, W) 50m transects you will determine the presence of the variables on the data sheet in a single point as determined by using the ocular-tube. 5 meters may be paced off, but please remember to step across the road if the transect spans it and continue counting on the other side. Count the number of hits (within 1cm) for each transect and each variable. In many cases the terrain or vegetation will not permit you to use the ocular-tube (e.g. cliffs, impenetrable chamise, etc.) at each point along the transect. In these cases you should estimate the number of hits for variables along the transect, keeping in mind this data will be used as an estimate of cover along the transect Dominant plant species are recorded next. Please rank the most dominant by percent cover and be sure to only include species that have at least 10% cover within the 50m radius. Point quarter distance determination should be done from the point established off the road. You will measure the distance from the point to the center of closest individual in the various categories for each of the 4 cardinal quadrants. Remember to exclude the road in distance determinations. B. Raw Data For raw data, please see the excel file Pine_Flat_Veg_Data_Supplement.xlsx, archived at ACR s Cypress Grove Research Center.

15 C. Sample Data Sheet METRICS FOR VEGETATION ANALYSIS OF AVIAN POINT COUNT STATIONS ALONG PINE FLAT ROAD. Cypress Grove Research Center, Audubon Canyon Ranch 26 June Visual assessment of vegetation alliances within 400 m (use the California Manual of Vegetation, Sawyer and Keeler-Wolf, Evens 2009). A. Percent of the area within 400m used (visible) to assess the vegetation assemblages Percent of area within 400m visually assessed B. Percent of the area within 400 m that is represented by discrete assemblages found in the study area (include assemblages greater than 1 acre for uplands and greater than 0.5 acre for special assemblages such as small wetlands, riparian and serpentine). Alliance Percent of 400m circle Notes, including seral stage if appropriate. 2. Visual estimate of vegetation assemblage within 50 m radius circle A. Foliage height for each foliage category Foliage height category Maximum Median Trees foliage canopy ( >5m) Shrub foliage canopy (0.5-5m) Ground-cover foliage canopy (0-2m) B. Evidence of fire: presence/absence of charred stems or wood.

16 Evidence of charred wood Yes / No C. Count the number of each of the following special features within 50 m Special feature Rock outcrops Near-vertical (slope>80%), unvegetated cliffs or erosional headcuts > 2 m high, Open water Stream with running water Spring, seep area, indicated by associated vegetation Fallen logs > 30 cm in diameter at largest point Standing snags > 20 cm dbh Cattle trough Bird (nest) box Slash pile (small diameter branches and twigs), patch of dead shrubs, or fallen patch of dead small-diameter stems (pile > 1 m tall and separated from next pile by > 1 m) Count D. Point-intercept, ocular-tube counts ( hits within 1 cm) at 5-m intervals along cardinal (N, E. S, W) 50-m transects (n = 10 per transect) Tally Variable N E S W Canopy foliage (direct foliage hit or miss) Shrub level foliage (porosity<1 cm) Ground-level foliage (porosity<1 cm) Bare ground hits Leaf litter hits (small-diameter dead twigs, recently fallen needles and leaves, unaltered or minimally altered by decomposition) Presence of duff layer >2cm in depth (partially decomposed material beneath the litter layer). Dead wood or stem m of ground (porosity<1 cm) Dead wood or stem m above ground (porosity<1 cm) E. List up to three most dominant plant species (cover >10%) within 50 m (rank by greatest percent cover; consider porosity by excluding unoccupied space in the cover estimate); use visual estimate of percent cover.

17 Dominance rank Category 1 Tree canopy>5 m above ground 2 Tree canopy>5 m above ground 3 Tree canopy>5 m above ground 1 Shrub canopy m above ground 2 Shrub canopy m above ground 3 Shrub canopy m above ground 1 Ground cover canopy 0-2m above ground 2 Ground cover canopy 0-2 m above ground 3 Ground cover canopy 0-2 m above ground Species name Percent cover F. Point quarter distances (m) within 50 m by cover rank (see E) Category Large trees > 30 cm dbh Small trees cm dbh Saplings, woody stems 3-10 cm dbh Rank 1 tree species > 50 cm dbh Rank 1 tree species cm dbh Rank 2 tree species > 50 cm dbh Rank 2 tree species cm dbh Rank 3 tree species > 50 cm dbh Rank 3 tree species cm dbh All woody shrub species (combined) > 1 m tall Rank 1 shrub species > 1 m tall Rank 2 shrub species > 1 m tall Rank 3 shrub species > 1 m tall Slash pile, dead shrub, or dense fallen patch > 1m tall of dead small-diameter stems (at least 1m away from other patches) Species name N (0-90) E (90-180) S ( ) W ( )

18 D. Author s note regarding associated data files From: Gregory Vose [mailto:gregvsf@gmail.com] Sent: Thursday, September 24, :14 PM To: John Kelly <john.kelly@egret.org> Subject: Re: Vegetation Data and Greetings! Hi John, Please find attached the documents I have been working on for the data summary of the Pine Flat Road vegetation surveys. Pine_Flat_Road_Vegetation_Data_Summary_ docx The word document includes a short summary of the project, methods, data summary tables for calculated values, some graphics and an appendix with the field protocol and blank data sheet. Pine_Flat_Veg_Data_ xlsx Pine_Flat_Veg_Data_Supplement_ xlsx I have also included 2 Excel documents. The "supplement" document is just the raw data along with a tab that has descriptions of each of the column headings. This is the one designed to go with the data summary. The other excel document is the one I have been working from which contains my calculated values along with the graphics. The graphics currently only contain info pertaining to the structural and vegetation density elements of the study... Thanks again for all your help on this project John. I hope that this data will be helpful to future projects that ACR undertakes. Again, I would love to continue working on this document if there are improvements you would like to see made. Just let me know. Also, please let me know if you have any questions about any aspects of the report. Best, Greg Vose