Print Report
M117 Fouquieria splendens - Atriplex hymenelytra - Amaranthus watsonii North American Rock Vegetation Macrogroup
Type Concept Sentence: This macrogroup consists of a variety of near barren and sparsely vegetated substrates in the southwestern U.S. and northern Mexico, including Baja California, including coastal areas, saline plains, desert pavement, rocky slopes, cliffs, and outcrops in foothills, canyons and desert mountain ranges.
Common (Translated Scientific) Name: Ocotillo - Desert-holly - Watson''s Amaranth North American Rock Vegetation Macrogroup
Colloquial Name: North American Warm Semi-Desert Cliff, Scree & Rock Vegetation
Hierarchy Level: Macrogroup
Type Concept: This macrogroup consists of near barren and sparsely vegetated landscapes on a variety of substrates across the southwestern U.S. and northern Mexico, including Baja California. It may be divided into two main groups: pavement, badlands, and outcrops or southwestern North American dunes and sandsheets. Vegetation is variable depending on environmental factors of the sites, which range from below sea level to foothill and lower montane elevations. Lower elevation sites often have herbaceous or shrub species present, whereas foothill and lower montane sites may also include scattered trees. Most of the tree species also occur in non-sparse vegetation groups. Common species of the Sonoran Desert include Amaranthus watsonii, Eucnide rupestris, Ficus spp., Hofmeisteria spp., Maytenus phyllanthoides, Nicotiana obtusifolia, and Pleurocoronis laphamioides [excluded]. In the alluvial fans and low mountains of the Mojave Desert and adjacent Sonoran Desert, differential shrubs include Atriplex hymenelytra and Atriplex confertifolia (basic to alkali substrate), Nolina bigelovii, Peucephyllum schottii, and Pleurocoronis pluriseta. Thorny and stem succulent shrubs such as Echinocactus polycephalus, Fouquieria splendens, Ferocactus cylindraceus, and Cylindropuntia bigelovii may be present. The nearly ubiquitous Mojave and Sonoran desert shrubs Larrea tridentata and Encelia farinosa are often present in rocky Mojave Desert stands, while at higher elevations in the desert mountains, Eriogonum fasciculatum, Eriogonum heermannii, and Ericameria cuneata occur. Calciphile species such as Agave utahensis, Buddleja utahensis, Ephedra funerea, Petrophytum caespitosum, and Salvia funerea occur on limestone and marble outcrops. Certain annual herbs such as Perityle sp. are particularly characteristic of these massive outcrops.
Nonvascular (lichens) plants are the predominant lifeform in some desert areas of higher precipitation. Species diagnostic of desert pavements and badland clay flats or mud hills are composed primarily of ephemeral annuals, which disclose themselves only in years of favorable precipitation. Several herbaceous species such as Eriogonum inflatum, Coreopsis sp., and Plantago ovata may occur on both clay-rich flats and mud hills, or on desert pavements, while others such as Chorizanthe rigida and Geraea canescens are most characteristic of pavements (so called due to the oxidized patina which slowly accumulates on surface rocks and pebbles), which are often underlain by a cemented duripan of calcium carbonate (caliche) making them impervious to roots of larger desert shrubs. Several species of annual Eriogonum spp. as well as Chorizanthe spp. may occur on pavements in the northern Sonoran and Mojave deserts. Another suite of annual ephemeral species are diagnostic of mud hills and flats, such as Coreopsis calliopsidea, and Eriogonum trichopes (Mojave).
Landforms include cliffs, narrow canyons, and smaller rock outcrops in desert mountains; pebbly pavement in xeric basins and alluvial fans; and upland areas around playas and washes. Sparse vegetation also occurs on special substrates such as shale or mudstone outcrops in badlands and volcanic deposits such as tuff and basal lava. Rock substrates include bedrock and unstable talus slopes in desert mountains. Some substrates, such as marine shales, are strongly alkaline and/or saline, which chemically limits plant growth. Active substrates such as scree slopes are difficult sites for plants to grow. Physical properties of substrates may also limit plant growth. Badland sites often have heavy clay soils that reduce water infiltration or availability (colloidal binding), increasing erosion rates and reducing soil moisture for plants.
Nonvascular (lichens) plants are the predominant lifeform in some desert areas of higher precipitation. Species diagnostic of desert pavements and badland clay flats or mud hills are composed primarily of ephemeral annuals, which disclose themselves only in years of favorable precipitation. Several herbaceous species such as Eriogonum inflatum, Coreopsis sp., and Plantago ovata may occur on both clay-rich flats and mud hills, or on desert pavements, while others such as Chorizanthe rigida and Geraea canescens are most characteristic of pavements (so called due to the oxidized patina which slowly accumulates on surface rocks and pebbles), which are often underlain by a cemented duripan of calcium carbonate (caliche) making them impervious to roots of larger desert shrubs. Several species of annual Eriogonum spp. as well as Chorizanthe spp. may occur on pavements in the northern Sonoran and Mojave deserts. Another suite of annual ephemeral species are diagnostic of mud hills and flats, such as Coreopsis calliopsidea, and Eriogonum trichopes (Mojave).
Landforms include cliffs, narrow canyons, and smaller rock outcrops in desert mountains; pebbly pavement in xeric basins and alluvial fans; and upland areas around playas and washes. Sparse vegetation also occurs on special substrates such as shale or mudstone outcrops in badlands and volcanic deposits such as tuff and basal lava. Rock substrates include bedrock and unstable talus slopes in desert mountains. Some substrates, such as marine shales, are strongly alkaline and/or saline, which chemically limits plant growth. Active substrates such as scree slopes are difficult sites for plants to grow. Physical properties of substrates may also limit plant growth. Badland sites often have heavy clay soils that reduce water infiltration or availability (colloidal binding), increasing erosion rates and reducing soil moisture for plants.
Diagnostic Characteristics: Diagnostic characteristics of this macrogroup are its substrates, which are sparsely vegetated by vascular plants, and its geographic location in the southwestern U.S. and northern Mexico, including Baja California. Vegetation is variable; however, it is often composed of scattered shrubs, perennial herbs (particularly cushion plants) and annual herbs that are adapted to the harsh environmental conditions that are making the site sparse, although either may be absent on a given site. Nonvascular species, especially lichens but also algae, bacteria, and mosses, are important on some sites as they represent the early stages of primary succession. Biological soil crusts (associations of nonvascular species) can be particularly important and diverse (based on substrate, moisture availability, disturbance, etc.) and may dominate the site (Belnap and Lange 2003).
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This macrogroup is very diverse floristically, often composed of ephemeral annuals, and more information is needed to sort out indicator species. What is diagnostic is the sparse cover of vascular plants and/or presence and sometimes dominance of nonvascular (lichen) species. This broadly defined macrogroup is similar to the single group included in it, ~North American Warm Semi-Desert Cliff, Scree & Pavement Sparse Vegetation Group (G569)$$, and it may or may not need to be split. This group is broadly defined and may need to be split into additional groups representing finer concepts of sparsely vegetated substrates/landforms such as rockland, scree and cliffs, desert pavements, or shale badlands or clay hills.
There is some discussion whether all of the sparsely vegetated portions of ~North American Warm Semi-Desert Dune & Sand Flats Group (G675)$$, which is currently included in ~Mojave-Sonoran Semi-Desert Scrub Macrogroup (M088)$$, should be included in this macrogroup with G569. The concept of a group including semi-desert sea cliffs in Baja, Mexico, and saline flats needs to be developed as coastal sparse vegetation could be expected to have different floristics due to proximity of salt spray. These new groups will be used to further refine the concept of this macrogroup or to define a related macrogroup.
T. Keeler-Wolf pers. comm. (2014): The sparsely vegetated desert macrogroup is limited by real field data; since these types are only expressed during El Niño years, it is hard to obtain. Some commentary from other ecologists (J. Evens pers. comm. 2014) emphasize the likely low diagnostic value of some of the species I listed (e.g., Eriogonum nudum, Chorizanthe rigida, Geraea canescens), since these species are also found in harsher desert shrublands as well. However, the strong presence of these in high cover in favorable rainfall years, in consort with the paucity of very many diagnostic woody species, enables these ephemeral herbs to be used as differentials. In other words, the sparsely vegetated desert landscapes are the least favorable settings for any vascular plant species, so the species that are present consistently there are also "diagnostic" of these harsh settings. There are reasonable diagnostic shrubs for the massive sparsely vegetated rock outcrop portion of G569. The affinity of species such as Peucephyllum schottii, Pleurocoronis pluriseta, Ephedra funerea, Salvia funerea, etc. to sparsely vegetated rock outcrops is expected to be relatively high, once more synoptic data are available.
There is some discussion whether all of the sparsely vegetated portions of ~North American Warm Semi-Desert Dune & Sand Flats Group (G675)$$, which is currently included in ~Mojave-Sonoran Semi-Desert Scrub Macrogroup (M088)$$, should be included in this macrogroup with G569. The concept of a group including semi-desert sea cliffs in Baja, Mexico, and saline flats needs to be developed as coastal sparse vegetation could be expected to have different floristics due to proximity of salt spray. These new groups will be used to further refine the concept of this macrogroup or to define a related macrogroup.
T. Keeler-Wolf pers. comm. (2014): The sparsely vegetated desert macrogroup is limited by real field data; since these types are only expressed during El Niño years, it is hard to obtain. Some commentary from other ecologists (J. Evens pers. comm. 2014) emphasize the likely low diagnostic value of some of the species I listed (e.g., Eriogonum nudum, Chorizanthe rigida, Geraea canescens), since these species are also found in harsher desert shrublands as well. However, the strong presence of these in high cover in favorable rainfall years, in consort with the paucity of very many diagnostic woody species, enables these ephemeral herbs to be used as differentials. In other words, the sparsely vegetated desert landscapes are the least favorable settings for any vascular plant species, so the species that are present consistently there are also "diagnostic" of these harsh settings. There are reasonable diagnostic shrubs for the massive sparsely vegetated rock outcrop portion of G569. The affinity of species such as Peucephyllum schottii, Pleurocoronis pluriseta, Ephedra funerea, Salvia funerea, etc. to sparsely vegetated rock outcrops is expected to be relatively high, once more synoptic data are available.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This lithomorphic macrogroup may be composed of woody plants, including both trees and shrubs, herbaceous plants, and/or nonvascular plants. Shrubs are especially common and were chosen as indicator species; however, herbs (especially cushion plants) and nonvasculars such as mosses or lichens may be more common. Lichen species could have been used as nonvascular organisms are important and often dominate stands of this macrogroup.
Floristics: Vegetation is variable depending on environmental factors of the sites, which range from sea level to foothill/lower montane elevations. Lower elevation sites often have herbaceous or shrub species present, whereas foothill, montane and subalpine sites may also include trees. Most of the species also occur in non-sparse vegetation groups. Common coastal species include Amaranthus watsonii, Eucnide rupestris, Ficus spp., Hofmeisteria spp., Maytenus phyllanthoides, Nicotiana obtusifolia (= Nicotiana trigonophylla), and Pleurocoronis laphamioides [excluded]. In the foothills and low mountains, Bursera microphylla, Fouquieria splendens, Juniperus deppeana, Nolina bigelovii, Cylindropuntia bigelovii (= Opuntia bigelovii), and Pinus discolor are often present. On harsh shaly substrates, Atriplex hymenelytra is common. Mud hills and badlands may just have scattered annual herbs, especially Eriogonum trichopes. Gypsum hills often have scattered plants such as Argemone munita, Nicotiana spp., Peucephyllum schottii, and annual Eriogonum spp. The nearly ubiquitous Larrea tridentata and Eriogonum fasciculatum are often present on pavement and rocky slopes. At higher elevations in the desert mountains, Eriogonum fasciculatum, Eriogonum heermannii, and Ericameria cuneata occur. Calciphile species such as Agave utahensis, Buddleja utahensis, Petrophytum caespitosum, Salvia funerea, and Ephedra funerea occur on limestone and marble outcrops. Certain annual herbs such as Perityle sp. are particularly characteristic of these massive outcrops.
Nonvascular (lichens) plants and biological soil crusts (e.g., associations of algae, bryophytes, cyanobacteria, lichens, liverworts, and microfungi) are the predominant lifeform in some areas. Species diagnostic of desert pavements and badlands clay flats or mud hills are composed primarily of ephemeral annuals, which disclose themselves only in years of favorable precipitation and temperature. Several herbaceous species such as Camissonia spp., Chaenactis spp., Coreopsis sp., Eriogonum inflatum, and Plantago ovata may occur on both clay-rich flats and mud hills, or on desert pavements. Others, such as Chorizanthe rigida and Geraea canescens, are characteristic of pavements (so called due to the oxidized patina which slowly accumulates on surface rocks and pebbles), which are often underlain by a cemented duripan of calcium carbonate (caliche) making them impervious to roots of larger desert shrubs. Several species of annual Eriogonum as well as Chorizanthe may occur on pavements in the northern Sonoran and Mojave deserts. Another suite of annual ephemeral species are diagnostic of mud hills and flats, such as Coreopsis calliopsidea and Eriogonum trichopes (Mojave).
Floristic information was compiled from Shreve and Wiggins (1964), Brown (1982a), Barbour and Major (1988), MacMahon (1988), Dick-Peddie (1993), Sawyer and Keeler-Wolf (1995), Keeler-Wolf et al. (1998), Belnap and Lange 2003, Barbour et al. (2007), Keeler-Wolf (2007), Schoenherr and Burk (2007), and Sawyer et al. (2009).
Nonvascular (lichens) plants and biological soil crusts (e.g., associations of algae, bryophytes, cyanobacteria, lichens, liverworts, and microfungi) are the predominant lifeform in some areas. Species diagnostic of desert pavements and badlands clay flats or mud hills are composed primarily of ephemeral annuals, which disclose themselves only in years of favorable precipitation and temperature. Several herbaceous species such as Camissonia spp., Chaenactis spp., Coreopsis sp., Eriogonum inflatum, and Plantago ovata may occur on both clay-rich flats and mud hills, or on desert pavements. Others, such as Chorizanthe rigida and Geraea canescens, are characteristic of pavements (so called due to the oxidized patina which slowly accumulates on surface rocks and pebbles), which are often underlain by a cemented duripan of calcium carbonate (caliche) making them impervious to roots of larger desert shrubs. Several species of annual Eriogonum as well as Chorizanthe may occur on pavements in the northern Sonoran and Mojave deserts. Another suite of annual ephemeral species are diagnostic of mud hills and flats, such as Coreopsis calliopsidea and Eriogonum trichopes (Mojave).
Floristic information was compiled from Shreve and Wiggins (1964), Brown (1982a), Barbour and Major (1988), MacMahon (1988), Dick-Peddie (1993), Sawyer and Keeler-Wolf (1995), Keeler-Wolf et al. (1998), Belnap and Lange 2003, Barbour et al. (2007), Keeler-Wolf (2007), Schoenherr and Burk (2007), and Sawyer et al. (2009).
Dynamics: These sparsely vegetated plant communities often represent primary succession on parent materials such as bare rock outcrops or disturbance-maintained communities such as scree and talus slopes that are frequently disturbed and constantly re-establishing themselves. Biological soil crusts can improve soil stability and soil fertility, and disturbances such as grazing and non-native species invasion can negatively impact these crusts (Belnap and Eldridge 2003, Belnap et al. 2006).
Environmental Description: This macrogroup occurs on near barren or sparsely vegetated landscapes on a variety of substrates across the Chihuahuan, Sonoran, and Mojave deserts, extending into Baja California. Landforms include cliffs, narrow canyons, and smaller rock outcrops and scree slopes in foothills and desert mountains; pebbly pavement in desert basins and alluvial fans; upland areas around playas and washes, saline coastal plains, clay hills, gypsum outcrops, rocky slopes, cliffs, and rock outcrops in foothills.
Geology is variable and includes igneous, sedimentary, and metamorphic rock types such as shale or mudstone outcrops in badlands and volcanic deposits such as tuff and basalt lava. Rock substrates also include bedrock and unstable scree slopes in mountains. Some substrates, such as marine shales, are strongly alkaline and/or saline which chemically limits plant growth. Active substrates such as scree slopes are difficult sites for plants to grow. Physical properties of substrates may also limit plant growth. Badland sites often have heavy clay soils that decease water infiltration, increase erosion rates and reduce soil moisture for plants. Environmental information was compiled from Shreve and Wiggins (1964), Brown (1982a), Barbour and Major (1988), MacMahon (1988), Dick-Peddie (1993), Sawyer and Keeler-Wolf (1995), Barbour et al. (2007), Keeler-Wolf (2007), Schoenherr and Burk (2007), and Sawyer et al. (2009).
Geology is variable and includes igneous, sedimentary, and metamorphic rock types such as shale or mudstone outcrops in badlands and volcanic deposits such as tuff and basalt lava. Rock substrates also include bedrock and unstable scree slopes in mountains. Some substrates, such as marine shales, are strongly alkaline and/or saline which chemically limits plant growth. Active substrates such as scree slopes are difficult sites for plants to grow. Physical properties of substrates may also limit plant growth. Badland sites often have heavy clay soils that decease water infiltration, increase erosion rates and reduce soil moisture for plants. Environmental information was compiled from Shreve and Wiggins (1964), Brown (1982a), Barbour and Major (1988), MacMahon (1988), Dick-Peddie (1993), Sawyer and Keeler-Wolf (1995), Barbour et al. (2007), Keeler-Wolf (2007), Schoenherr and Burk (2007), and Sawyer et al. (2009).
Geographic Range: This macrogroup occurs in scattered locations across the southwestern U.S. and northern Mexico in the Chihuahuan, Mojave, and Sonoran deserts extending to Baja California and including coastal areas and islands in the Gulf of California.
Nations: MX,US
States/Provinces: AZ, CA, MXBCN, MXBCS, MXCHH, MXSON, NM, NV, TX
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.860641
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 3 Desert & Semi-Desert Class | C03 | 3 |
| Subclass | 3.A Warm Desert & Semi-Desert Woodland, Scrub & Grassland Subclass | S06 | 3.A |
| Formation | 3.A.2 Warm Desert & Semi-Desert Scrub & Grassland Formation | F015 | 3.A.2 |
| Division | 3.A.2.Na North American Warm Desert Scrub & Grassland Division | D039 | 3.A.2.Na |
| Macrogroup | 3.A.2.Na.6 Ocotillo - Desert-holly - Watson''s Amaranth North American Rock Vegetation Macrogroup | M117 | 3.A.2.Na.6 |
| Group | 3.A.2.Na.6.a Ocotillo - Bear-grass species - Desert-holly Rock Vegetation Group | G569 | 3.A.2.Na.6.a |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: No Data Available
- Barbour, M. G., T. Keeler-Wolf, and A. A. Schoenherr, editors. 2007a. Terrestrial vegetation of California, third edition. University of California Press, Berkeley.
- Belnap, J., S. L. Phillips, and T. Troxler. 2006. Soil lichen and moss cover and species richness can be highly dynamic: The effects of invasion by the annual exotic grass Bromus tectorum, precipitation, and temperature on biological soil crusts in SE Utah. Applied Soil Ecology 32(1):63-76.
- Belnap, J., and D. Eldridge. 2003. Disturbance and recovery of biological soil crusts. Pages 363-383 in: J. Belnap and O. L. Lange, editors. Biological soil crusts: Structure, function, and management ecological studies. Volume 150. Springer, Berlin Heidelberg.
- Belnap, J., and O. L. Lange, editors. 2003. Biological soil crusts: Structure, function, and management. Second edition. Springer-Verlag, Berlin.
- Brown, D. E., editor. 1982a. Biotic communities of the American Southwest-United States and Mexico. Desert Plants Special Issue 4(1-4):1-342.
- Dick-Peddie, W. A. 1993. New Mexico vegetation: Past, present, and future. University of New Mexico Press, Albuquerque. 244 pp.
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Keeler-Wolf, T. 2007. Mojave Desert scrub vegetation. Pages 609-656 in: M. G. Barbour, T. Keeler-Wolf, and A. A. Schoenherr, editors. Terrestrial vegetation of California. Third edition. University of California Press, Berkeley.
- Keeler-Wolf, T., C. Roye, and K. Lewis. 1998a. Vegetation mapping and classification of the Anza-Borrego Desert State Park, California. Unpublished report on file at California Natural Diversity Database, California Department Fish and Game, Sacramento.
- MacMahon, J. A. 2000. Warm deserts. Pages 285-322 in: M. G. Barbour and W. D. Billings, editors. North American terrestrial vegetation. Second edition. Cambridge University Press, New York.
- MacMahon, J. A., and F. H. Wagner. 1985. The Mojave, Sonoran and Chihuahuan deserts of North America. Pages 105-202 in: M. Evenari and D. W. Goodall, editors. Ecosystems of the world 12A: Hot deserts and arid shrublands. Elsevier, New York.
- Schoenherr, A. A., and J. H. Burk. 2007. Colorado Desert vegetation. Pages 657-682 in: M. G. Barbour, T. Keeler-Wolf, and A. A. Schoenherr, editors. 2007. Terrestrial vegetation of California. Third edition. University of California Press, Berkeley.
- Shreve, F., and I. L. Wiggins. 1964. Vegetation and flora of the Sonoran Desert. Stanford University Press, Stanford, CA. 840 pp.