Flora of the Meadows of Tahquitz Valley,
San Jacinto Mountains
San Jacinto Mountains
Introduction
Analysis and Numerology of Taxa Found in the Tahquitz Valley Meadows
Plant Checklist
References
Introduction
The Meadows are one of the major delights of Tahquitz Valley, providing large open areas filled with plants, insects, birds and occasionally deer, and in summer providing a mass of greenery and flowers unrivaled almost anyplace else in Tahquitz Valley.
Meadows in general are areas with a high groundwater level, high enough so that water is essentially at the soil surface in places for at least several months per year. That high groundwater level prevents shrubs and trees from becoming established, and provides the perfect habitat for mostly-perennial herbaceous species that love to have their roots in water most of the growing season. Since these species transpire much less water than a shrub or a tree, this is a positive feedback loop that keeps the groundwater level high in the meadows.
In Tahquitz Valley, with one exception, the meadows are found in the flatter areas of the drainages below the ridges that ring the Valley. In and above the meadows, snow accumulates to great depths during the winter. The snow melt, both flowing above ground and in groundwater, converges on the areas of the meadows, where the water is concentrated enough that the groundwater level comes to the surface. The flatter areas where the meadows are formed allow the groundwater to flow slowly enough away from the meadows to keep the groundwater level high for at least several months. The slower-flowing water in the meadows forms part of another positive feedback loop, that allows soil to accumulate, making the area flatter.
The one exception is Reeds Meadow, which is found in a flatter area where the drainages from three other Tahquitz Valley Meadows converge, again resulting in a high groundwater level.
Unfortunately, these meadows are being rapidly destroyed by a period of rapid erosion that has occurred in the last 100 years due to heavy cattle grazing. This timescale is literally roughly 10,000 times greater than the natural time scale for the destruction of these meadows.
Meadows naturally are destroyed on a geologic time scale of typically millions of years as mountain ranges are uplifted and erosion destroys previously flattish surfaces. In particular, Tahquitz Valley itself is a fairly small remnant surface that is slowly being eroded away on all sides except its north side, due to relative uplift of San Jacinto Mountain in the last 2.6 million years. At the estimated knickpoint migration rate of 12 to 44 km / MY at its edges, Tahquitz Valley will be completely eroded in 0.3-1.0 million years (0.8 mi radius / 12-44 km / MY). The meadows will be gone long before that.
In a wet meadow, the soil is bound tightly by a very dense collection of roots from the perennial species, and shielded from intense rainfall by the dense above-ground vegetation. Heavy cattle grazing affects both; cattle eat the dense above-ground vegetation, exposing the soil, and their trampling destroys the binding of the soil. When heavy rains come in summer thunderstorms, the loose soil is then carried away. The additional soil in the runoff water enhances the erosion force, carving gullies. This creates a feedback loop that operates in a destructive manner. As the first tiny gully is formed, it gives more erosive power to the water runoff, which rapidly deepens the gully with every heavy rain. Within a time scale of decades, deep gullies are formed, which then begin to drain the high groundwater table of the meadow, destroying them as wet meadows. This gullification has happened in many environments throughout the west that have been subjected to heavy grazing, and has been well documented, often through historical photographs.
Little Tahquitz Meadow has already been completely destroyed by creek incision. Tahquitz Creek is incised by (six?) feet there now, which has completely drained the meadow. There is no wet meadow left above the banks of Tahquitz Creek. The former meadow area is still evident, but it is essentially a monoculture of wild tarragon, Artemisia dracunculus, and may soon revert to being a forest. The flora of Little Tahquitz Meadow very clearly shows what has happened; it is very depauperate compared to the other meadows (see analysis below). The only wet areas remaining are those within the banks of Tahquitz Creek little different from a number of areas along the Creek in areas where its bank is forested.
Reeds Meadow is a meadow that is in the process of being destroyed. Most of the area of Reeds Meadow is no longer a wet meadow. However, due to its special location at the convergence of the drainages from three other meadow areas, its total destruction has been delayed. The incised Tahquitz Creek is along only one edge of it, removing only one of its former sources of groundwater and providing only one edge to drain the meadow. As a result, the drying of Reeds Meadow has happened so recently that one can still observe two former meadow levels, one of which still has a few intact giant root mounds of the main meadow sedge, Carex senta. These giant root mounds will be gone within a decade or so.
Both Tahquitz Meadow and Skunk Cabbage Meadow have had smaller drying, but the creeks in those meadows are incised, and the groundwater level, and the soil surface itself, is significantly lower in portions of those meadows. The meadows themselves have lost several feet of soil on average, as can be immediately discovered by walking across the meadows. The Carex senta roots now are one to two feet above the surrounding soil surface. This makes for a hazardous walk across the meadow since the leaves cover both the root balls and the deep gaps between the plants, hiding the topography. Since these plants didn't originally have their roots two feet up in the air, the surrounding soil surface has been lost in the time since these plants were established. The days of these meadows are also numbered unless measures are taken to reverse the creek incision.
Due primarily to its location 1,000 feet above the other meadows, Wellman Cienega is the most intact meadow, with creek incision still below the bottom of the meadow. But the creek incision is inexorably working its way upstream. It remains to be seen how much damage will be caused to Wellman Cienega when the new equilibrium creek profile is reached.
Similar erosion was poised to destroy Round Valley Meadow, in an older remnant surface above and to the north of Tahquitz Valley. Fortunately, the State Park took action in 2010 to preserve the Meadow. Similar actions are needed in the Forest Service-managed Tahquitz Valley.
See also pages on some of the individual meadows:
For a shorter print version that just includes the number of plants for Tahquitz Meadow, see html (4 pages) or pdf Clickbook booklet (1 double-sided page). (See printing instructions for an explanation of these options).
Analysis and Numerology of Taxa Found in the Tahquitz Valley Meadows
Note the following major caveat that applies to all the analysis in this section. The checklists for every one of these meadows are incomplete, due to insufficient surveys, and that there is considerable unevenness in the checklists for different meadows. Hence this analysis must be considered preliminary.
This analysis was done on checklist as of 2012, which used the 1993 first edition Jepson Manual names. The checklist below has been updated, and so no longer exactly corresponds to this analysis.
With that caveats in mind, Table 1 gives a summary of the number of taxa found in each Meadow.
Table 1. Preliminary Number of Taxa Found in Each Meadow
| # Taxa | SCM | TQM | LTM | RM | WC |
|---|---|---|---|---|---|
| observed | 97 | 98 | 51 | 79 | 79 |
| vouchered, not observed | 6 | 7 | 0 | 0 | 0 |
| total | 103 | 105 | 51 | 79 | 79 |
The column heading abbreviations are defined below.
The number of native taxa is expected to correlate with the size of the meadow and its elevation. The parameters for each meadow are given in Table 2, in descending order of meadow size, along with the total number of taxa known from each meadow. In Table 2, for a few meadows we have combined species and subspecies into a single taxon for two species where we expect only one is present.
Table 2. Area, Elevation and Perimeter Length for Tahquitz Valley Meadows
| Meadow | Area (acres) | # Native Taxa | Perimeter (miles) | Elevation range (feet) | Elevation range (m) |
|---|---|---|---|---|---|
| Tahquitz | 20.5 | 103 | 1.2 | 7840-8040 | 2390-2450 |
| Skunk Cabbage | 15.5 | 98 | 1.3 | 7900-7940 | 2410-2420 |
| Wellman Cienega | 10.5 | 79 | 0.7 | 8960-9420 | 2730-2870 |
| Little Tahquitz | 7.5 | 51 | 0.5 | 7960-8080 | 2425-2460 |
| Reeds | 2.4 | 79 | 0.3 | 7680-7720 | 2430-2355 |
Figure 1 plots the number of taxa vs. meadow area, both from just our surveys and with the inclusion of vouchered species that we have not observed. We also fit a power law to the data for Tahquitz Meadow, Skunk Cabbage Meadow, and Reeds Meadow, without vouchers, since that is a more uniform data set. We excluded Little Tahquitz Meadow from the fit since the plot shows that it is very depauperate for species. We excluded Wellman Cienega from the fit since it is roughly 1,000 feet higher in elevation, and a number of species are not found at such high elevation. The best-fit exponent for the area was a very low 0.09, reflecting the uniformity of habitat for those three meadows.
Figure 1. Number of Native Taxa in each Meadow vs. Area of Meadow
Figure 1 shows the expected trend for each meadow except for Little Tahquitz Meadow, whose flora is significantly more depauperate since that meadow has essentially been drained by incision of Tahquitz Creek through it. There is essentially no wet meadow remaining outside of the incised creek. One prominent example of a missing species is that Little Tahquitz Meadow is the only meadow that does not have any Veratrum californicum, a strong component of all the other wet meadows, and of boggy areas throughout the high elevations of San Jacinto Mountain. The former wet meadow of Little Tahquitz Meadow outside of the incised creek is now a very dry meadow dominated by Artemisia dracunculus. (We note that V. californicum is missing in most of the area of Tahquitz Meadow, too, reflecting the impact of grazing on it as well.)
The incision of Tahquitz Creek is historically recent (see Hamilton 1983, p. 102-104, for discussion of the impact caused by grazing, and further references). The boggy areas in Little Tahquitz Meadow are confined to the Creek channel, and its flora is now little different from other portions of Tahquitz Creek. The same process is occurring in Reeds Meadow, but it has retained more wet area due to high groundwater along the Candy's Creek area, which is coming in roughly perpendicular to Tahquitz Creek.
Reeds Meadow still retains evidence of the recent Tahquitz Creek incision, with two prominent terraces above the current level of the banks of Tahquitz Creek, some of which still retain root clumps of the formerly wide-spread large Carex senta plants. If not for the high groundwater delivered by the Candy's Creek drainage, and the Creek itself, Reeds Meadow would be as depauperate as Little Tahquitz Meadow.
Another rough idea of the completeness for each survey can be gleaned by considering the number of species found in only a single meadow out of these five; the number found in exactly two of the meadows; up to those found in all five meadows. The actual numbers are given in Table 3, and the numbers converted to percentages are plotted in Figure 2. We have excluded vouchers from these numbers, and combined the subspecies of Epilobium ciliatum, which are difficult to separate, so that the list of species in each meadow is comparable. In addition, it is not always certain from which meadow a species was vouchered.
Table 3. Number of Observed Native Species Found in N Total Meadows
| # Total Meadows | SCM | TQM | LTM | RM | WC |
|---|---|---|---|---|---|
| 1 | 10 | 5 | 0 | 3 | 12 |
| 2 | 9 | 16 | 5 | 8 | 12 |
| 3 | 22 | 25 | 5 | 18 | 14 |
| 4 | 22 | 21 | 12 | 21 | 12 |
| 5 | 29 | 29 | 29 | 29 | 29 |
| total | 92 | 96 | 51 | 79 | 79 |
The 29 species found in all five meadows can be easily found in the Checklist by scanning for species with entries in all five columns, and combining the subspecies of Epilobium ciliatum, which are difficult to separate.
Figure 2. Percent of Species vs. # of Meadows in which they occur
Once again, Little Tahquitz Meadow stands out as being different from the other four meadows. It is the only one with no species unique to it. Over half the species found in it are common ones that are found in the other four meadows. All other meadows have about one-third of their species being such common species.
It is also a bit surprising that Wellman Cienega, does not appear different in Figure 2 than Skunk Cabbage Meadow and Tahquitz Meadow, despite being at significantly higher elevation, over 1000 feet (300 m) higher.
Table 4 gives the breakdown for the number of species found in N total meadows, for the entire meadow checklist, considering just the 134 native species we've observed from any meadow. (The total checklist contains 151 taxa, the 134 native species we've observed; eight vouchered native species we haven't observed; seven non-native species; and the two other entries for Epilobum ciliatum).
Table 4. Number of Observed Native Species Found in N Total Meadows from All Meadows
| # Total Meadows | # Species | % Species |
|---|---|---|
| 1 | 30 | 22 % |
| 2 | 25 | 19 % |
| 3 | 28 | 21 % |
| 4 | 22 | 16 % |
| 5 | 29 | 22 % |
| total | 134 | 100 % |
This is a pretty even distribution, as expected since the habitat is much the same in all these meadows. (Compare to the usual declining power law with a strong peak at being found in just one location.)
Plant Checklist
The following gives some basic information about this checklist.
See:
- Notes on the Scientific Names Used At This Site and
- Information about the links from the Scientific Name and Common Name.
An asterisk before the common name indicates a non-native species.
The checklist gives the minimum number of plants observed in each meadow, or in their immediate vicinity, up to a maximum of 99 plants, with the following exceptions:
- We find it impossible to tell the two subspecies of Epilobium ciliatum apart, except by digging around the roots of each plant to look for evidence of turions. This is far too time-consuming and invasive to do for every plant observed.
In all the meadows except Wellman Cienega and Tahquitz Meadow, we have observed turions on at least one plant, and hence have made the minimalist assumption that all the plants of the species are ssp. glandulosum. In Tahquitz Meadow, in addition to seeing some plants with turions, we observed one plant with no evidence of turions, which must then be ssp. ciliatum, which is also vouchered from there. We arbitrarily divided the 70 plants we saw of the species equally into the two subspecies, which might not be correct.
- In Tahquitz Meadow, one species, Montia chamissoi, did not have an abundance estimate made for it, and that column just contains an x to indicate that we observed that species there.
- Species that are vouchered from a meadow, but which we have not observed yet, have a V in their column, seven from Tahquitz Meadow and six from Skunk Cabbage Meadow.
The column heading abbreviations are:
Fam: The first three letters of the 2012 second edition Jepson Manual Family name. See Plant Family Abbreviations.
SCM: Skunk Cabbage Meadow
TQM: Tahquitz Meadow
WLM: Wellman Cienega (both portions)
RM: Reeds Meadow
LTM: Little Tahquitz Meadow
Notes on some non-observed vouchered species:
- Allophyllum gilioides ssp. violaceum. The two vouchers by Hall and by Jaeger may or may not have been from one of the meadows, and may or may not be correctly determined.
- Notes on Some Vouchered Species in Skunk Cabbage Meadow.
Version for printing, without other text on this page: html (6 pages) or pdf Clickbook booklet (2 double-sided pages). (See printing instructions for an explanation of these options)
References
Hamilton, Michael P. 1983. A floristic basis for the management of rare plants and their communities in the San Jacinto Mountains, California. Dissertation Thesis. Cornell University. 189 pp.
Voucher data provided by the participants of the Consortium of California Herbaria (ucjeps.berkeley.edu/consortium/).