Flora of Borrego Springs Desert Floor Survey on 14 March 2017

Survey Results and Analysis


The authors spent a day in 90 degree plus heat on 14 March 2017 to do eight quick spot surveys of a number of different places on the desert floor at prime time in a very good flowering year, when nearly all the species could be determined with high reliability. The goals were to obtain more GPS points for areas on the Borrego Desert Floor, for improved species mapping, and to characterize the load of non-native species in this opportune year while the Sahara Mustard, Brassica tournefortii, has been knocked back by drought. But as if often the case with any scientific investigation, the survey yielded some other interesting results.

The first five surveys were done in a uniform manner, surveying the desert floor for an area approximately, but nowhere near exactly, 100 feet x 100 feet. The three subsequent surveys were done differently, including some hillside habitat above the desert floor in two of them (#5b and #7), and surveying in two different spots in one of them (#6), and thus the numbers from those surveys can not be directly compared to the first five surveys.

The survey areas are shown in Fig. 1, and described in Table 1.

As a result of the compilation of results here, we plan on returning to most of these survey areas to make sure that species found in most of the other survey areas, but missing from one or two survey areas, really are missing from those areas, rather than our just failing to record the species in those areas.

Fig. 1. Google Earth map showing the areas surveyed on 14 March 2017 (white circles), identified with a # sign with the survey number given in Table 1, mostly above the white circles, with the number of species found in each area mostly given to the right of the white circles. The size of the white circles is unrelated to the area surveyed.

Table 1. Survey areas with number of species found

#Hdr^# speciesLocale
1HO29Hoberg Road
2BS127Borrego Springs Road near Bighorn Road
3BS238Borrego Springs Road just south of its junction with Henderson Canyon Road
4HC127Horse Camp Road just north of the last orchard
5aHC243Horse Camp Road just south of the Horse Camp (desert floor)
5bHC37Horse Camp Road just south of the Horse Camp (additional species on the hill immediately to the west)*
6HCR20Henderson Canyon Road at sunflower field*
7CC41Coyote Creek Road hillside survey and adjacent desert floor*

^ This column gives the header label in the checklist below that identifies each survey area.

* These surveys were not done in a comparable fashion to the first five surveys, and hence the numbers of species can not be directly compared to those surveys.

Survey Results and Analysis

Non-native Percent Cover

In all the surveys, we estimated that the total non-native coverage was on the order of just 5% of the total area. To our surprise, nearly all of that was due to Schismus, with Brassica tournefortii and Erodium cicutarium being fairly minor contributors. We had expected those latter two species to contribute more to the non-native load.

The low non-native coverage was especially surprising given that there are huge monocultures of both B. tournefortii and Sisymbrium irio within a short distance of survey site #2. Those monocultures are often specific to certain real estate parcels, implying that past land use resulted in conversion from a desert flora to a non-native flora.

Comparison of species counts

In the first five surveys, three areas have species counts of 27, 27, and 29, and two areas have species counts of 38 and 43. The first three are typical desert floor habitat. The area with a species count of 38 is at the edge of the alluvial fan from Henderson Canyon, and hence has species typical of both the alluvial fan and the desert floor. The area with a species count of 43 is at the base of the mountains to the west, and hence has additional species from that habitat. In fact, a quick survey of a single hill to the immediate west quickly found 7 additional species.

Of the three surveys with typical desert floor habitat, the total number of species from all three surveys is 47, indicating that the habitat varies significantly even on the desert floor proper. Starting with the Hobert Road survey with 29 species as a baseline, there are an additional 10 species in the survey at Borrego Springs Road near Bighorn Road, for a total of 39 species from those two survey areas. There are an additional eight species in the survey at the Horse Camp Road just north of the last orchard, for a total of 47 unique species from all three areas.

Other survey results

There are some other interesting results from an analysis of the checklist below. Here are a few, which may or may not be statistically significant, but would be interesting to pursue further with additional surveys.

Checklist for Borrego Springs Desert Floor Survey Areas on 14 March 2017


An asterisk before the common name indicates a non-native species.

The column with header #Bl gives the total number of plants in bloom seen on the whole day from all areas, up to a maximum of 99 plants, compiled from memory a day later. This includes a stop along Borrego Dump Road where no survey was conducted. Some species have a question mark on the number, since we couldn't recall for sure how many plants were in bloom.

The survey areas, with their abbreviation in the column names, along with the number of species found in each spot, are given in Table 1, in the same order as given in the checklist from left to right.

The column with header # Plants gives the number of plants found in each area, up to a maximum of 99 plants. If no estimate of the abundance was made, an x is given in that column.

This checklist is by no means complete for the entire Borrego Desert Floor; it lists only 107 taxa, compared to 270 taxa in the complete list.

Version for printing, without lines and other text on this page: html (4 pages) or pdf Clickbook booklet (1 double-sided pages). (See printing instructions for an explanation of these options)

#FamScientific Name(*)Common Name#Bl# Plants
1AcaJusticia californicachuparosa3?    3   
2AmaAmaranthus albus*tumble pigweed      99  
3AstAmbrosia acanthicarpabur-ragweed      1  
4AstAmbrosia dumosaburroweed10?20353   x
5AstAmbrosia salsola var. salsolacheesebush 2  1   1
6AstBebbia juncea var. asperasweetbush        5
7AstChaenactis carphoclinia var. carphocliniapebble pincushion       350
8AstChaenactis fremontiiFremont pincushion995 2099x  1
9AstChaenactis stevioidesdesert pincushion20 99      
10AstEncelia farinosabrittlebush4   13   
11AstGeraea canescenshairy desert-sunflower99    299  
12AstHelianthus petiolaris ssp. canescensgray desert sunflower10     10  
13AstLogfia depressadwarf filago3    x   
14AstLogfia filaginoidesCalifornia filago9999 99     
15AstMalacothrix glabratadesert dandelion999999999999  x
16AstPalafoxia arida var. aridaSpanish needle1   2 2  
17AstPerityle emoryiEmory's rock-daisy99    1  99
18AstRafinesquia neomexicanadesert chicory9928199 1   
19AstStephanomeria pauciflorawire-lettuce     1   
20AstStylocline gnaphaloideseverlasting nest-straw 1       
21AstVolutaria tubuliflora*Mediterranean desert knapweed5  8    10
22BorCryptantha angustifolianarrow-leaved cryptantha9999999999995 99
23BorCryptantha barbigera var. barbigerabearded cryptantha102 2 2  4
24BorCryptantha ganderiGander's cryptantha1        
25BorCryptantha intermedia var. intermediapopcorn flower2     5  
26BorCryptantha maritimaGuadalupe cryptantha205      20
27BorCryptantha micrantha var. micranthared-root cryptantha99  20 99   
28BorEmmenanthe penduliflora var. penduliflorawhispering bells5    20  3
29BorNama demissa var. demissapurple mat20  50 1   
30BorPectocarya heterocarpachuckwalla pectocarya999950x50    
31BorPectocarya peninsularisBaja pectocarya999920x     
32BorPectocarya platycarpabroad-fruited combseed16   16    
33BorPectocarya recurvatacurvenut combseed11  1x   
34BorEucrypta micrantha99      99 
35BorPhacelia crenulata var. minutifloralittle-flowered heliotrope phacelia70       70
36BorPhacelia distanscommon phacelia99991174x   
37BorPhacelia ivesianaIves' phacelia1        
38BorTiquilia palmeriPalmer's coldenia        2
39BorTiquilia plicataplicate coldenia      5  
40BraBrassica tournefortii*Sahara mustard30?830151750  2
41BraCaulanthus lasiophyllusCalifornia mustard2      3 
42BraDescurainia pinnatawestern tansy-mustard?      25 
43BraDithyrea californicaspectacle-pod1       1
44BraLepidium lasiocarpum ssp. lasiocarpumhairy-podded pepper-grass     1  1
45BraSisymbrium irio*London rocket 520  10   
46CacCylindropuntia bigeloviiteddy-bear cholla     40   
47CacCylindropuntia echinocarpasilver cholla   15     
48CacCylindropuntia ganderiGander's cholla 15  40    
49CacFerocactus cylindraceusCalifornia barrel cactus     1   
50CamNemacladus glanduliferusglandular nemacladus10       15
51CarAchyronychia cooperifrost mat99  995 1  
52CheAtriplex canescens var. laciniataCaleb saltbush      2  
53CheSalsola tragus*Russian thistle      1  
54CraCrassula connatapygmy-weed 99       
55EupChamaesyce polycarpasmall-seeded spurge21 1   5 
56EupCroton californicusCalifornia croton?  1     
57EupDitaxis lanceolatanarrowleaf ditaxis?       20
58FabAcmispon maritimus var. brevivexillusshort-bannered coastal lotus2    1  1
59FabAcmispon strigosusstrigose lotus5       5
60FabAstragalus didymocarpus var. dispermusdwarf white milk-vetch5 1 2    
61FabAstragalus lentiginosus var. borreganusBorrego milk-vetch1     1  
62FabLupinus arizonicusArizona lupine99 303 8  99
63FabLupinus concinnusbajada lupine1    1   
64FabLupinus shockleyidesert lupine10        
65FabPsorothamnus emoryiEmory's indigo-bush1  1010    
66FabPsorothamnus schottiiindigo bush510 2 2  15
67FouFouquieria splendens ssp. splendensocotillo1    10   
68GerErodium cicutarium*redstem filaree 9910  3   
69GerErodium texanumTexas filaree 1501 1   
70KraKrameria bicolorwhite rhatany?  152   
71LamHyptis emoryidesert-lavender1    1  x
72LamSalvia columbariaechia10      20 
73LoaMentzelia affinisyellow blazing star25 25      
74LoaMentzelia involucratabracted blazing star8       8
75LoaPetalonyx thurberi ssp. thurberiThurber's sandpaper-plant   223   
76MalEremalche exiliswhite mallow99 99   30  
77MalEremalche rotundifoliadesert five-spot3       3
78MonCalyptridium monandrumsand cress?9999991040   
79NycAbronia villosa var. villosahairy sand-verbena99 252530 40  
80NycAllionia incarnata var. incarnatasmall-flowered trailing four o'clock1       1
81OnaCamissoniopsis pallida ssp. pallidapale suncup9950999910x1  
82OnaChylismia claviformis ssp. peirsoniibrown-eyed primrose99 509950x10 99
83OnaEremothera chamaenerioideslong-fruit suncup1    1   
84OnaEulobus californicusCalifornia suncup99996209999  2
85OnaOenothera deltoides ssp. deltoidesdune primrose99     99  
86PapEschscholzia minutiflora ssp. minutiflorasmall-flowered poppy30  30 x   
87PapEschscholzia parishiiParish's poppy99    3  99
88PhrMimulus bigelovii var. bigeloviiBigelow's monkeyflower99  1    99
89PlaPlantago ovatadesert plantain? 5      
90PolAliciella latifolia ssp. latifoliabroad-leaf gilia2       15
91PolEriastrum diffusumminiature woolly-star1        
92PolGilia stellatastar gilia5  1 5   
93PolLoeseliastrum matthewsiidesert calico1025081099   
94PolSaltugilia australissouthern gilia      1  
95PolChorizanthe brevicornu var. brevicornubrittle spineflower 25      1
96PolEriogonum thomasiiThomas' buckwheat5  1 2  50
97PolEriogonum trichopeslittle desert trumpet  7      
98SolDatura discolordesert thornapple1   1   1
99SolNicotiana obtusifoliadesert tobacco        1
100SolPhysalis crassifoliathick-leaved ground cherry        1
101ZygFagonia laevisCalifornia fagonia1      199
102ZygLarrea tridentatacreosote bush10504035  20  
103AgaHesperocallis undulatadesert lily40 40213323   
104PoaAristida adscensionissix-weeks three-awn        5
105PoaBouteloua aristidoides var. aristidoidesneedle grama50       50
106PoaHilaria rigidabig galleta   4    4
107PoaSchismus barbatus*Mediterranean schismus 99999999x99  

Go to:

Copyright © 2017 by Tom Chester, Nancy Accola, Walt Fidler, RT Hawke, Don Rideout, Karyn Sauber, and Myrna Wosk (authors in alphabetical order after the first author)
Permission is freely granted to reproduce any or all of this page as long as credit is given to us at this source:
Comments and feedback: Tom Chester
Last update: 18 March 2017