Who Grows There? Analyzing Montane Meadow
Vegetation as an Indicator of Hydrologic Stress
Ryuko Novak-Murano, Dr. Hillary Jenkins
ryuko_novak-murano@redlands.edu
University of Redlands, Department of Environmental Studies, 1200 E. Colton Ave, Redlands, CA 92374
Abstract/Background
Montane meadows are biodiversity hotspots, hosting unique annual and perennial vegetation, small mammals, arthropods, and a robust community of pollinators Because meadows respond to natural and anthropogenic stressors, they serve as near real-time indicators of the ecological impacts of climate change Vegetative communities in meadows are the surface expression of numerous environmental factors, including soil, climate, and hydrology, and their relationships
Most existing environmental research on subalpine meadow ecosystems has been conducted on meadows in the Sierra Nevada mountains Here, we examine vegetation distribution at three meadow sites (Lodgepole, Bluff, and Broomflat) in the San Bernardino National Forest and compare this with underlying hydrology (characterized by depth to groundwater), enriching our understanding of unique ecosystems in the Inland Empire Species richness, vegetation identification and type, maximum and minimum height, and percent bare ground were collected across 1x1 yard plots within each meadow Vegetation composition data was then used to generate a wetland indicator species distribution for each meadow based on the National Wetland Plant List available via the US Army Corps of Engineers (USACE) and the US Department of Agriculture (USDA) Plants Database The smallest meadow, Lodgepole, is dominated by facultative forb and grass species and exhibits traits of a hydrologically healthy wet meadow that is experiencing cyclical drought stress The intermediate meadow, Bluff, is mainly sedge and grass species returning to a recharging water table (indicated by the resurgence of Bluff Lake) The largest meadow, Broomflat, is also the driest, having a notable proportion of shrubs as well as facultative wetland rushes concentrated around one small pond Understanding the relationship between vegetation and hydrology in threatened meadow ecosystems provides an important basis for understanding how shifting climates will impact these vital systems
II. Classifying Vegetative Communities
Vegetation Typing
NWPL Indicator Classes
IV. The Influence of Water
Water Availability and Species Abundance
I. Methodology
Wetland Species Counts
Common Vegetation Types Found in Meadows
1. Rushes: family Juncaceae
2. Sedges: family Cyperaceae
3. Forbs: various families of leafy, non-woody herbs
4. Grasses: family Poaceae
5. Shrubs: various families of woody, bush-like plants
III. Spatial Analysis
Wetland Species Distribution
Species Richness vs. Water Table Depth
Field Methods
• Measured 1 x 1-yard plots proximal to piezometer (groundwater well) sites
• Estimated bare ground within plots
• Counted plant species within plots
• Measured min and max vegetation heights
• Extracted samples for herbarium collection
• As Lodgepole becomes drier, species richness declines, but as Bluff becomes drier, species richness increases
• Lodgepole’s wet species are dying while prolonged drying in Bluff has allowed expansion of drought tolerant species
• A higher proportion of dry (FACU) species versus wet (OBL) species suggests that wetland species may be more vulnerable to drought
Lab Methods
• Processed data using Excel to identify correlations
• Identified species and assigned dominant species' water needs (NWPL indicator status)
• Used ArcGIS Pro to map spatial trends
• Pressed and dried field specimens, mounted dried plant pressings in an herbarium
• Drier vegetation (FAC and FACU species) was more prevalent in the Western regions of Broomflat and the Eastern regions of the BluffLodgepole system
• Wetter vegetation (FACW and OBL species) was more prevalent around standing water in the Eastern region of Broomflat and in the Western regions of the Bluff-Lodgepole system
V. Conclusions
Can montane meadow vegetation be classified by hydrologic need at the community level?
How is the species diversity related to a meadow’s hydrologic health?
Does the current distribution of meadow vegetation types suggest resilience against climate change?
Yes. Using the classes outlined in the US Army Corps of Engineers’ National Wetland Plant List we found broad connections between distribution of wetland to nonwetland species and underlying hydrology across all three meadow sites.
A greater diversity of species was found in Bluff and Lodgepole compared to Broomflat, however, correlation between species richness and water table depth was positive in Bluff but negative in Lodgepole.
A lower proportion of wetland species suggests that meadows in the San Bernardino mountains are less adapted to long-term drought conditions.
Acknowledgements
• Drier meadows (Broomflat) generally exhibit diminished species richness relative to wet meadows (Lodgepole)
Special thanks to The Summer Science Research Program and my generous donor Mrs. Levings for making this experience possible. Thank you to my advisor Dr. Hillary Jenkins, the Environmental Science Department, US Fish & Wildlife, the US Forest Service, our research team: Marina Wesel, Paola Rosas, Abby Dimicco, and Kayla Smith, and our volunteers in the field: Dr. Eric Hill, Gavin Jewell, TJ Carson, and Isaac Dogbegah
Figure 2. Stacked Bar Chart of the frequency of 5 major vegetationtypes (Rush, Sedge, Forb, Grass, and Shrub) acrossBluff, Lodgepole, and Broomflat
Indicator Status Ecological Description Lichvar and Minkin (2008) % Expected Occurrence in Wetland Habitats Obligate Wetland OBL (1) Almost always a hydrophyte, rarely in uplands 99 Facultative Wetland FACW (2) Usually is a hydrophyte but occasionally found in uplands 67-99 Facultative FAC (3) Commonly occurs as either a hydrophyte or non-hydrophyte 34-66 Facultative Upland FACU (4) Occasionally is a hydrophyte, but usually occurs in uplands 1-33 Upland UPL (5) Rarely is a hydrophyte, almost always occurs in uplands 1
Figures 3A and B. Diagram (3A) depicting National Wetland Plant List wetland regimes relative to surface water availability (US Army Corps of Engineers). Wetland Delineation Model (3B) courtesy of Penn State(2017).
Figure 9. Distribution of Meadow Species by National Wetland Plant List (NWPL) category. Plots chosen were broadly representativeof expected subalpine meadow vegetation.
Figure 8. Scatterplot of Depth to Water versus Species Count in Bluff (left panel) and Lodgepole (right panel).
NWPL values were assigned for each species/vegetation type found across each meadow site.
Meadow Vegetation were classified by their NWPL Indicator Status to determine plant and community-level water needs.
Figure 6. Maps depicting depth to water in Broomflat (A) versus the density of vegetative species (B) and the depth to water in Bluff and Lodgepole (C) versus the corresponding density of vegetative species (D) in those meadows. Note the legend for depth to water is the same across all three meadows (panels A and B).
Figure 7. Bar chart of species richness vs. water table depth in all three meadows
Figures 4 and 5. NWPL class distribution in Broomflat (left panel), Lodgepole and Bluff Meadows (right panel).
Figure 1. Photographsof the three study sites (left to right) Bluff Meadow, Lodgepole Meadow, and Broomflat Meadow.
A B
A B C D
Lodgepole Bluff Broomflat