Clark, Curtis, and Nancy A. Charest. 1992. Vegetation survey of the Antelope Valley California Poppy Reserve. Crossosoma 18(1):15-24.
Vegetation Survey of the
Antelope Valley California Poppy Reserve

by Curtis Clark and Nancy Charest
Biological Sciences, California State Polytechnic University, Pomona CA 91768

In 1983, we carried out a study of the California poppies (Eschscholzia californica) and other vegetation in the Antelope Valley California Poppy Reserve, under contract with the California Department of Parks and Recreation (CDPR). The ultimate purpose of the study was to identify the factors responsible for floral displays of California poppies in the Reserve. Because public attention has once again been focused on the poppy displays (and their absence), we are making the results of our study known. This first part concerns the vegetation of the Reserve. Two additional papers will follow. One will address the contrast between the annual poppies of the Reserve and the perennial poppies south of the nearby small settlement of Fairmont. The other will consider the general question of the factors that promote poppy displays.

Materials and Methods

On 9 April 1983 we began a line-intercept transect in the area of maximum poppy display east of the Visitors Center (at a post just east of a "No Vehicles" sign) and extending north (magnetic compass bearing 347 deg.) for 400 m toward the Antelope buttes (Fig. 1, line "L"). This transect was completed on 16 April. We sampled every other 10 m increment of the transect, for a total of 20 individual samples totaling 200 m. The total length of the transect intercepted by each species was recorded, and from this information relative cover for each species was calculated for each sample. Since the data included the presence/absence of each species in each sample, we also calculated relative frequency for each species for the entire line.

On 23 April we began a different sampling technique: at set intervals along a line a 1 m2 open wooden frame was placed (to the right or left of the line, depending on the toss of a coin), and Braun-Blanquet cover classes (Mueller-Dombois and Ellenberg, 1974) and phenology were estimated for each species. Overall cover was obtained by averaging the cover classes of a number of samples, and relative frequency from the number of samples containing a given species divided by the total number of samples.

The following lines (Fig. 1) were sampled in this manner:

Parallel to the south boundary and about 20 m north, in the region of greatest display. Twenty-three samples at 10 m intervals, 23 April.

Parallel to the previous line, about 20 m further north. Twenty-three samples at 10 m intervals, 23 April.

From the region of greatest display north to the crest of the hills and across, to the north boundary. Twenty-two samples at 20 m intervals, 23 April.

From the crest of "Encelia hill" (the highest point in the main ridge, dominated by Encelia actoni) to the crest of north Godde Hill. Thirty-three samples at 20 m intervals, 23 April.

From the eastern boundary to the top of Rattlesnake Hill, thence west into the main range of hills. Forty-three samples at 20 m intervals, 30 April.

Just south of the north boundary on the east slope of north Godde Hill to a point on the north slope of Encelia Hill. Thirty-five samples at 20 m intervals, 30 April.

Totals: 179 samples, 3.12 km of sample line.


Fig. 1. Map of Antelope Valley California Poppy Reserve (1982 boundaries) showing sample lines and previously tilled areas.

map


RESULTS

The vegetation of the reserve at the time of the survey can best be characterized as annual grassland, although in many areas grasses were not a dominant part of the vegetation. From Tables 1 and 2, Fig. 2, and Appendix 1, it is apparent that the dominant vegetation consisted of annual forbs. Most of the plants were native. Of the nine most important species, either by cover or by frequency, three were introductions. Redstem filaree (Erodium cicutarium), very widespread in dry environments all over the state, and thought by some to have reached California prior to European settlement (Wester, 1981), seemed to fill in the spaces between other annuals. Cheatgrass (Bromus tectorum), another common weed in desert environments, was more common in hilly parts of the Reserve. Red brome (Bromus rubens) was only common along trails and in other areas of human disturbance. Of the thirty-five most important identified species, only six were introductions.


Fig. 2. Relative cover from line-intercept sample. Segments 7-20 had been burned in 1981.

relative cover graph


The most important native grass was Festuca megalura (vulpia or foxtail fescue; there is some question whether this North American member of a circumboreal species group was originally found in California). The native bunchgrass, desert needlegrass (Stipa speciosa), was the eleventh most important species by cover and the fourteenth by frequency. Another bunchgrass (possibly Melica imperfecta) was seventh by cover and ninth by frequency.

The most important native forbs were pygmy lupine (Lupinus bicolor), goldfields (Lasthenia chrysostoma), owl clover (Orthocarpus purpurascens), and California poppy (Eschscholzia californica). The poppy was ninth by cover and seventh by frequency, even though poppies would not be expected in many parts of the reserve, and there was only one area of display. The seedlings of a perennial wild buckwheat (Eriogonum sp.) that flowers in the summer were ninth in importance by cover and eighth by frequency.

Shrub species were uncommon; the only shrubs to show up in the vegetation analysis were Corethrogyne filaginifolia and Encelia actoni; the latter was an artifact of one transect beginning at the highest point in the southern range of the Antelope Buttes (Encelia Hill), which is the only place in the reserve where that species occurs. Rabbitbrush (Chrysothamnus nauseosus) was not infrequent on many of the north-facing slopes, but many burned stumps gave testimony to a much greater abundance prior to a fire in 1981. Beavertail pricklypear (Opuntia basilaris) was also locally abundant and recovering from that fire.

Although we did not quantify vegetational differences between north-facing and south-facing slopes, some differences were readily apparent by visual inspection: poppies were most common on south-facing slopes and goldfields on north-facing slopes, and lupine was found everywhere.

As mentioned, introduced species were most common in areas of disturbance. The grounds around the Visitors Center supported large amounts of tumble-mustard (Sisymbrium altissimum), and some species, such as pineapple weed (Matricaria matricarioides) were found only along roads and paths.

Some parts of the Reserve had been previously tilled (Fig. 1). These areas had no more introduced species than untilled areas, but their species composition did differ. This was most apparent in the eastern part of the Reserve. Sampling transect 5 crossed the most recently tilled section (it appeared to be still in use in aerial photographs from 1970 supplied by CDPR) and ended on the untilled shoulders of the hills. Lupine was by far the most common species in the tilled section (and visual examination confirmed that in the rest of the tilled area), but at the edge (which still shows up as a physical ridge in the terrain), the vegetation changed dramatically, with owl clover becoming much more abundant. Further west, in the region of the poppy displays of 1983 and some previous years, the land was also tilled, but much longer ago, and vegetational differences were not as apparent.

Although the lack of baseline information about the vegetation hampers the comparison, it appears that fire has had a significant effect. Accounts of the Reserve before the fires of 1978, 1980, and 1981 in unpublished CDPR files implied a greater abundance of rabbitbrush and other shrub species, and aerial photographs taken by Jim Trumbly of CDPR in 1978 show a greater abundance of shrubs. Many of the charred stumps of rabbitbrush seen in our study showed considerable regrowth, but others were clearly dead, and many may have been totally burned, leaving no trace two years later. The fires may have also been in part responsible for the absence of large numbers of introduced species.

Table 1. Important plants of the line-intercept transect.

Species

Average relative cover Relative frequency

Lupinus bicolor

0.400 1.000

Erodium cicutarium

0.366 1.000

Festuca megalura

0.105 0.700

Eschscholzia californica

0.091 0.850

Bromus rubens

0.018 0.600

Bromus tectorum

0.008 0.150

 

Table 2. Important species in descending order of cover and frequency, based on Braun-Blanquet cover class transects.

Average Braun-Blanquet
Cover Class
Relative Frequency
Lupinus bicolor 3.34 *Erodium cicutarium 0.99
*Erodium cicutarium 2.65 Lupinus bicolor 0.99
Festuca megalura 1.42 Festuca megalura 0.68
*Bromus rubens 1.35 *Bromus rubens 0.66
Lasthenia chrysostoma 0.90 *Bromus tectorum 0.53
*Bromus tectorum 0.80 Lasthenia chrysostoma 0.46
unknown grass (Melica ?) 0.44 Eschscholzia californica 0.34
Orthocarpus purpurascens 0.32 Eriogonum sp. (seedling) 0.24
Eschscholzia californica 0.23 unknown grass (Melica ?) 0.20
Eriogonum sp. (seedling) 0.23 Orthocarpus purpurascens 0.18
Stipa speciosa 0.08 Euphorbia polycarpa 0.12
unknown grass 0.08 Platystemon californicum 0.09
Euphorbia polycarpa 0.07 Trifolium sp. 1 0.07
Amsinckia tessellata 0.06 Amsinckia tessellata 0.06
Corethrogyne filaginifolia 0.05 Stipa speciosa 0.06
Platystemon californicum 0.04 unknown seedling 0.06
*Hordeum glaucum 0.03 unknown grass 0.06
Allium sp. 0.02 unknown seedling 0.06
Dichelostemma pulchella 0.02 Corethrogyne filaginifolia 0.06
Encelia actoni 0.02 Dichelostemma pulchella 0.04
Juncus sp. 0.02 *Hordeum glaucum 0.03
*Sisymbrium altissimum 0.02 Pectocarya sp. 0.02
unknown seedling 0.02 Cryptantha sp. 1 0.02
Pectocarya sp. 0.01 Allium sp. 0.01
Trifolium sp. 1 0.01 Chaenactis glabriuscula 0.01
Trifolium sp. 2 0.01 Cryptantha sp. 2 0.01
unknown grass 0.01 Encelia actoni 0.01
unknown seedling 0.01 unknown grass 0.01

*Brassica sp., Calystegia sp., Chaenactis glabriuscula, Cryptantha sp. 1, Cryptantha sp. 2, Cryptantha spp., Linanthus sp., Malacothrix californica, Mirabilis sp.

*Brassica sp., Calystegia sp., Cryptantha spp., Juncus sp., Linanthus sp., Malacothrix californica, Mirabilis sp., *Sisymbrium altissimum, Trifolium sp. 2

*introduced species

     

Conclusions

In 1983, the Antelope Valley California Poppy Reserve consisted of an annual grassland of chiefly native species, with introduced species most common in disturbed sites. Although anecdotal evidence suggests that shrubs were an important component of the vegetation during the 1970s and before, the shrub cover was not extensive in 1983, perhaps a result of fires in previous years.

Acknowledgments

We thank Emilia Parra, Mark Patterson, Donald Sanders, and Christina Wedaa for assistance in the field, and the California Department of Parks and Recreation for financial support and access to unpublished records and photographs.

References Cited

Mueller-Dombois, D. and H. Ellenberg. 1974. Aims and methods of vegetation ecology. John Wiley & Sons, New york. 547 pp.

Wester, L. 1981. Composition of native grasslands in the San Joaquin Valley, California. Madroño 28:231-241.


Appendix 1. Frequency and cover of species on Braun- Blanquet transects.

Transects 1 and 2

Relative frequency1 Relative frequency2 Average cover3

Amsinckia tessellata

0.03 0.07 0.03

Brassica sp.

0.00 0.03 0.00

Bromus rubens

0.26 0.42 0.55

Bromus tectorum

0.23 0.52 0.45

Erodium cicutarium

0.97 1.00 2.94

Eschscholzia californica

0.42 0.74 0.87

Euphorbia polycarpa

0.00 0.03 0.00

Festuca megalura

0.45 0.52 1.03

Hordeum glaucum

0.03 0.07 0.10

Lasthenia chrysostoma

0.00 0.07 0.00

Lupinus bicolor

0.90 0.97 3.32

Malacothrix californica

0.00 0.03 0.00

Transects 1 and 2 continued

     

Orthocarpus purpurascens

0.00 0.03 0.00

unknown seedling 2

0.00 0.13 0.00


Transect 3

Relative frequency1 Relative frequency2 Average cover3

Bromus rubens

0.78 0.87 2.39

Bromus tectorum

0.30 0.56 0.74

Chaenactis glabriuscula

0.00 0.09 0.00

Corethrogyne filaginifolia

0.04 0.04 0.09

Cryptantha sp. 1

0.00 0.04 0.00

Dichelostemma pulchella

0.00 0.04 0.00

Eriogonum sp. seedling

0.22 0.30 0.52

Erodium cicutarium

0.96 0.96 2.26

Eschscholzia californica

0.09 0.52 0.17

Euphorbia polycarpa

0.00 0.26 0.00

Festuca megalura

0.52 0.61 0.83

Lasthenia chrysostoma

0.39 0.48 1.26

Lupinus bicolor

1.00 1.00 3.13

Orthocarpus purpurascens

0.04 0.13 0.17

Platystemon californicum

0.00 0.09 0.00

Trifolium sp. 1

0.00 0.09 0.00

unknown bunchgrass

0.13 0.13 0.44

unknown grass 2

0.30 0.39 0.35

unknown seedling 2

0.04 0.09 0.04

Transect 4

Relative frequency1 Relative frequency2 Average cover3

Allium sp.

0.02 0.02 0.07

Bromus rubens

0.50 0.55 1.36

Bromus tectorum

0.39 0.46 0.93

Dichelostemma pulchella

0.00 0.02 0.00

Eriogonum sp. seedling

0.05 0.14 0.07

Erodium cicutarium

0.98 1.00 3.16

Eschscholzia californica

0.07 0.14 0.09

Euphorbia polycarpa

0.18 0.23 0.25

Festuca megalura

0.82 0.93 2.41

Lasthenia chrysostoma

0.46 0.68 0.96

Lupinus bicolor

1.00 1.00 3.98

Orthocarpus purpurascens

0.39 0.52 1.02

Transect 4 continued

     

Pectocarya sp.

0.02 0.02 0.05

Stipa speciosa

0.09 0.11 0.16

unknown bunchgrass

0.07 0.09 0.21

unknown grass

0.02 0.05 0.05

unknown seedling

0.00 0.02 0.00

Transect 5

Relative frequency1 Relative frequency2 Average cover3

Amsinckia tessellata

0.16 0.19 0.23

Bromus rubens

0.52 0.71 1.16

Bromus tectorum

0.42 0.58 0.97

Calystegia sp.

0.00 0.03 0.00

Corethrogyne filaginifolia

0.07 0.13 0.13

Cryptantha sp. 1

0.00 0.07 0.00

Cryptantha sp. 2

0.00 0.07 0.00

Dichelostemma pulchella

0.03 0.07 0.07

Encelia actoni

0.03 0.07 0.10

Eriogonum sp. seedling

0.19 0.29 0.32

Erodium cicutarium

0.97 1.00 2.68

Eschscholzia californica

0.07 0.23 0.10

Euphorbia polycarpa

0.00 0.03 0.00

Festuca megalura

0.26 0.32 0.55

Hordeum glaucum

0.00 0.07 0.00

Lasthenia chrysostoma

0.36 0.39 1.10

Linanthus sp.

0.00 0.03 0.00

Lupinus bicolor

0.94 1.00 3.26

Mirabilis sp.

0.00 0.03 0.00

Pectocarya sp.

0.00 0.03 0.00

Platystemon californicum

0.03 0.16 0.07

Stipa speciosa

0.00 0.07 0.00

Trifolium sp. 1

0.00 0.19 0.00

Trifolium sp. 2

0.03 0.03 0.03

unknown bunchgrass

0.29 0.39 0.74

unknown crucifer

0.00 0.03 0.00

unknown grass 2

0.03 0.03 0.16

Transect 6

Relative frequency1 Relative frequency2 Average cover3

Allium sp.

0.03 0.03 0.03

Amsinckia tessellata

0.03 0.06 0.06

Bromus rubens

0.60 0.83 1.51

Bromus tectorum

0.31 0.57 0.83

Corethrogyne filaginifolia

0.03 0.11 0.06

Dichelostemma pulchella

0.03 0.09 0.03

Eriogonum sp. seedling

0.23 0.49 0.37

Erodium cicutarium

0.91 1.00 1.97

Eschscholzia californica

0.00 0.20 0.00

Euphorbia polycarpa

0.00 0.06 0.00

Festuca megalura

0.69 0.86 1.69

Hordeum glaucum

0.03 0.03 0.06

Juncus sp.

0.03 0.03 0.09

Lasthenia chrysostoma

0.43 0.57 1.20

Lupinus bicolor

0.91 0.97 2.77

Orthocarpus purpurascens

0.03 0.06 0.09

Pectocarya sp.

0.00 0.06 0.00

Platystemon californicum

0.06 0.20 0.11

Sisymbrium altissimum

0.03 0.03 0.09

Stipa speciosa

0.09 0.09 0.17

Trifolium sp. 1

0.03 0.11 0.06

unknown bunchgrass

0.40 0.40 0.86

unknown plant/purple fls.

0.00 0.03 0.00

unknown seedling

0.03 0.11 0.06

unknown seedling 3

0.03 0.29 0.06

unknown tall fuzzy plant

0.00 0.03 0.00

1. Braun-Blanquet cover classes "r" and "+" omitted.

2. Braun-Blanquet cover classes "r" and "+" included.

3. Average of Braun-Blanquet cover classes.


This page Copyright © 1992, 1999 by Curtis Clark.