UC Davis Department of Plant Sciences

Meadow Conditions on National Forest Grazing Allotments

Contact Person: Dr. Leslie Roche

Project Participants: Leslie Roche, Dave Weixelman, David Lile, Matt Freitas, Kristin Oles, Anton Jackson, Anne Yost

Sierra, Sequoia, and Inyo National Forests

At the time of this analysis (December 2013) the number of plots available with at least 8 years between their earliest (Reading 1 made between 1997 and 2002) and latest (Reading 2 made between 2007 and 2012) reading was 23, 25, and 42 on the Sierra, Sequoia, and Inyo National Forests, respectively. Here, we assess metrics of meadow vegetation condition and trend on these three forests using data from the plots with at least 8 years between Reading 1 and 2.

Meadow Plant Community Condition Metrics

Relative Frequency Data

At each monitoring plot, three parallel, 20 m long transects were permanently established 5 m apart in a location representing the dominant plant community at each plot. Along each transect, twenty 0.01 m2 quadrats were established at 1 m intervals for a total of 60 quadrats per site. All herbaceous plant species rooted within each 0.01 m2 quadrat were identified following Baldwin et al. (Baldwin et al. 2012). Plant community composition based on relative species frequency was determined at each plot for each reading (plot-reading).

Ratliff Vegetation Score and Condition Classification

Ratliff Scores

Table 1. Condition classification of Ratliff Vegetation
Scores based on relative frequencies of competitor
and intermediate species found in meadow
monitoring plots.

We followed Weixelman and Gross (In Preparation, Appendix 2) to assign all 1,018 herbaceous plant species encountered in the entire monitoring program to one of three broad indicator groups: 1) ruderals, 2) intermediates, and 3) competitors. For each plot-reading, we determined the relative frequencies of the three indicator groups. We then used Ratliff’s (1985, pp. 45-47, Table 16) rule set to calculate a Ratliff Vegetation Score (range 0 to 100) for each plot-reading based on competitor (i.e., decreaser) and intermediate (i.e., increaser) relative frequencies. We followed Ratliff’s generalized vegetation condition standards to assign each plot and reading into a Ratliff Vegetation Condition class based on the plot-reading Ratliff Vegetation Score (Ratliff 1985, Table 16). Scores from 0 to 24, 25-49, 50-74, and 75-100 were classified as Poor, Fair, Good, and Excellent condition, respectively (Table 1).

Species Richness and Dviersity

We calculated the number of species (richness) and Shannon-Wiener diversity (McCune and Grace 2002) for each plot-reading.

Results

Jump to: Sierra National Forest, Sequoia National Forest, Inyo National Forest

We found a significant increase in mean species richness and Shannon-Weiner Diversity from Reading 1 to Reading 2 on all three forests. There was no significant change in Ratliff condition class from Reading 1 to Reading 2. The interpretation of the Ratliff Vegetation Scores and Condition Classes is conducted by the Forest Service and is an ongoing process. For more information about these scores and classes, please see Ratliff 1985.

Comparison Table

Table 2. Comparison of meadow vegetation condition metrics for long-term monitoring plots located across the Sierra, Sequoia, and Inyo National Forests.


Sierra National Forest

SIE plots

Table 3. Years and number of meadow vegetation condition and trend plots read per year for Readings 1 and 2 on the Sierra National Forest. At the time of this analysis (December 2013) trend data was available from 23 plots that had two readings at least 8 years apart between 1999 and 2012.


SIE Vegetation Condition

Table 4. Ratliff meadow vegetation condition at Reading 2, and trend in condition from
Reading 1 to 2 for 23 long-term meadow monitoring plots on the Sierra National Forest.

SIE Vegetation score statistics

Table 5. Descriptive statistics for Ratliff vegetation score
(range 0 to 100, with a score of 50 or above being good
to excellent; Ratliff 1985) at Reading 1 and 2 for 23
meadow monitoring plots on the Sierra National Forest.
P Value < 0.05 indicates that mean score is significantly
different between Readings 1 and 2. Test was made
using linear mixed effects analysis with plot identity
treated as a random intercept to account for repeated
measures.

SIE Richness and Diversity

Table 6. Mean herbaceous vegetation richness and Shannon-Weiner diversity index at Reading 1 and 2 for 23 meadow vegetation condition and trend plots on the Sierra National Forest. P Value < 0.05 indicates that means are significantly different between Readings 1 and 2. Test was made using linear mixed effects analysis with plot identity treated as a random intercept to account for repeated measures.


Sequoia National Forest

SEQ plots

Table 7. Years and number of meadow vegetation condition and trend plots read per year for Readings 1 and 2 on the Sequoia National Forest. At the time of this analysis (December 2013) trend data was available from 25 plots that had two readings at least 8 years apart between 1997 and 2012.


SEQ Vegetation Condition

Table 8. Ratliff meadow vegetation condition at Reading 2, and trend in condition from
Reading 1 to 2 for 25 long-term meadow monitoring plots on the Sequoia National Forest.

SEQ Vegetation score statistics

Table 9. Descriptive statistics for Ratliff vegetation score
(range 0 to 100, with a score of 50 or above being good
to excellent; Ratliff 1985) at Reading 1 and 2 for 25
meadow monitoring plots on the Sequoia National Forest.
P Value < 0.05 indicates that mean score is significantly
different between Readings 1 and 2. Test was made
using linear mixed effects analysis with plot identity
treated as a random intercept to account for repeated
measures.


SEQ Richness and Diversity

Table 10. Mean herbaceous vegetation richness and Shannon-Weiner diversity index at Reading 1 and 2 for 25 meadow vegetation condition and trend plots on the Sequoia National Forest. P Value < 0.05 indicates that means are significantly different between Readings 1 and 2. Test was made using linear mixed effects analysis with plot identity treated as a random intercept to account for repeated measures.


Inyo National Forest

INY plots

Table 11. Years and number of meadow vegetation condition and trend plots read per year for Readings 1 and 2 on the Inyo National Forest. At the time of this analysis (December 2013) trend data was available from 42 plots that had two readings at least 8 years apart between 1999 and 2012.


INY Vegetation Condition

Table 12. Ratliff meadow vegetation condition at Reading 2, and trend in condition from
Reading 1 to 2 for 42 long-term meadow monitoring plots on the Inyo National Forest.

INY Vegetation score statistics

Table 13. Descriptive statistics for Ratliff vegetation score
(range 0 to 100, with a score of 50 or above being good
to excellent; Ratliff 1985) at Reading 1 and 2 for 42
meadow monitoring plots on the Inyo National Forest.
P Value < 0.05 indicates that mean score is significantly
different between Readings 1 and 2. Test was made
using linear mixed effects analysis with plot identity
treated as a random intercept to account for repeated
measures.


INY Richness and Diversity

Table 14. Mean herbaceous vegetation richness and Shannon-Weiner diversity index at Reading 1 and 2 for 42 meadow vegetation condition and trend plots on the Inyo National Forest. P Value < 0.05 indicates that means are significantly different between Readings 1 and 2. Test was made using linear mixed effects analysis with plot identity treated as a random intercept to account for repeated measures.

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