Home/Ecosystems/ Texas Hill Country Moist Canyon

Texas Hill Country Moist Canyon

EVT 7524Edwards Plateau Mesic Canyon

CES303.038GNRTreeHardwood

Summary

This ecological system is largely endemic to the Edwards Plateau ecoregion and occurs on canyon bottoms, mesic lower slopes and steep canyons, primarily in the Southern Balcones Escarpment, but also in the Eastern Balcones Escarpment. This system also includes cliff faces and lower slopes of boxed canyons occurring as narrow, sometimes long bands in areas often with seeps where moisture is consistently more available than on adjacent slopes. The tree canopy is generally closed. Common components include Ulmus crassifolia, Juglans major, Quercus buckleyi, Quercus laceyi, Prunus serotina var. eximia (becoming less common to the north), Fraxinus albicans (dominant in the northeastern plateau), Quercus muehlenbergii, and Acer grandidentatum. Canyon bottoms may have scattered Quercus macrocarpa. Substrate (limestone) and topographic position (north and east aspects and lower slopes) are the dominant characteristics of this system. Small seepage areas are often dominated by Adiantum capillus-veneris, with Thelypteris ovata var. lindheimeri on nearby moist habitats. Other prominent species include Buddleja racemosa, Ungnadia speciosa, and Toxicodendron radicans ssp. eximium. Fire probably plays little role in the system, while grazing and browsing (by native as well as exotic ungulates) may play an important role in recruitment and understory composition. Adjacent, drier slopes are usually dominated by various Quercus species and Juniperus ashei.

Source: NatureServe Explorer

Vegetation

The tree canopy is generally closed. Composition is variable among examples, depending on moisture status. Common components include Ulmus crassifolia, Juglans major, Quercus buckleyi, Quercus laceyi, Prunus serotina var. eximia (becoming less common to the north), Fraxinus albicans (= Fraxinus texensis) (dominant in the northeastern plateau), Quercus muehlenbergii, and Acer grandidentatum. Canyon bottoms may have scattered Quercus macrocarpa. Small seepage areas are often dominated by Adiantum capillus-veneris, with Thelypteris ovata var. lindheimeri on nearby moist habitats. Other prominent species include Buddleja racemosa, Ungnadia speciosa, and Toxicodendron radicans ssp. eximium. Mesic examples are characterized by the presence of Acer grandidentatum, with Quercus muehlenbergii as a common associate, along with Ulmus crassifolia, Juglans major, Quercus buckleyi, Quercus laceyi, Prunus serotina var. eximia (becoming less common to the north), and Fraxinus albicans (dominant in the northeastern plateau). Mesic herbaceous indicators such as Aquilegia canadensis and Clematis texensis may be present in these examples (Elliott 2011).

Source: NatureServe Explorer

Environment

This system is largely endemic to the Edwards Plateau ecoregion. Examples are associated with lower Cretaceous limestones of the Edwards Plateau, often on the Glen Rose or related formations. This system occurs on mesic lower slopes (toeslopes), canyon bottoms, and onto the margins of adjacent valleys of small drainages, primarily in the Southern Balcones Escarpment, but also in the Eastern Balcones Escarpment (also on the Limestone Cutplain). Occurrences are generally found in steep canyons where insolation is minimal, or on lower positions on northern- or eastern-facing slopes. This system also includes areas of cliff faces and lower slopes of boxed canyons occurring as narrow, sometimes long bands in areas often with seeps where moisture is consistently more available than on adjacent slopes. Soils are rich loams, often very rocky, with little soil development. It includes Steep Rocky Ecological Site, in part (Elliott 2011).

Source: NatureServe Explorer

Dynamics

Substrate (limestone) and topographic position (northern and eastern aspects and lower slopes) are the dominant characteristics of this system. Fire probably plays little role in the system, while grazing and browsing (by native as well as exotic ungulates) may play an important role in recruitment and understory composition.

Source: NatureServe Explorer

Distribution

Largely endemic to the Edwards Plateau ecoregion and occurs on canyon bottoms, mesic lower slopes and steep canyons, primarily in the Southern Balcones Escarpment, but also in the Eastern Balcones Escarpment.

Source: NatureServe Explorer

Ecologically Associated Plant Species

Plant species that characterize this ecosystem type, organized by vegetation stratum. These are species ecologically associated with the ecosystem, not confirmed present in any specific area.

Tree canopy

Acer grandidentatum, Fraxinus texensis, Juglans major, Juniperus ashei, Prunus serotina var. eximia, Quercus buckleyi, Quercus laceyi, Quercus macrocarpa, Quercus muehlenbergii, Ulmus crassifolia

Shrub/sapling (tall & short)

Buddleja racemosa, Ungnadia speciosa

Herb (field)

Adiantum capillus-veneris, Carex edwardsiana, Clematis texensis, Pelazoneuron ovatum var. lindheimeri, Toxicodendron radicans ssp. eximium

Source: NatureServe Ecological System assessment

Ecologically Associated Animals (3)

Animal species ecologically associated with this ecosystem type based on NatureServe assessment. These are species whose habitat requirements overlap with this ecosystem, not confirmed present in any specific roadless area.

Reptiles (1)

Common Name	Scientific Name	G-Rank
Texas Spiny Lizard	Sceloporus olivaceus	G5

Other (2)

Common Name	Scientific Name	G-Rank
Black-crested Titmouse	Baeolophus atricristatus	G5
Texas Alligator Lizard	Gerrhonotus infernalis	G4

Source: NatureServe Ecological System assessment

At-Risk Species Associated with this Ecosystem (3)

Species with conservation concern that are ecologically associated with this ecosystem type. G-Rank indicates global conservation status: G1 (critically imperiled) through G5 (secure). ESA status indicates U.S. Endangered Species Act listing.

Common Name	Scientific Name	G-Rank	ESA Status
Edwards Plateau Sedge	Carex edwardsiana	G3G4	--
Scarlet Virgin's-bower	Clematis texensis	G3G4	--
Black Cherry	Prunus serotina var. eximia	G5T2T4Q	--

Source: NatureServe Ecological System assessment

Component Associations (6)

Plant community associations that occur within this ecological system. Associations are the finest level of the U.S. National Vegetation Classification (USNVC) and describe specific, repeating assemblages of plant species. Each association represents a distinct community type that may be found where this ecosystem occurs.

Name	G-Rank
Acer grandidentatum - (Quercus muehlenbergii) / Carex edwardsiana Lampasas Cutplain Forest	G2	NatureServe
Acer grandidentatum - Quercus muehlenbergii - Quercus laceyi / Carex edwardsiana - Chaetopappa effusa Southern Edwards Plateau Forest	G2	NatureServe
Edward's Plateau Adiantum capillus-veneris - Thelypteris ovata var. lindheimeri Cliff	G2	NatureServe
Muhlenbergia reverchonii - Bouteloua hirsuta var. pectinata - Carex microdonta Grassland	G3	NatureServe
Quercus laceyi - Juniperus ashei Woodland	G2	NatureServe
Quercus muehlenbergii - Juglans major - (Ulmus rubra) / Verbesina virginica Forest	G2	NatureServe

State Conservation Ranks (1)

Subnational conservation status ranks (S-ranks) assigned by Natural Heritage Programs in each state where this ecosystem occurs. S1 indicates critically imperiled at the state level, S2 imperiled, S3 vulnerable, S4 apparently secure, and S5 secure. An ecosystem may be globally secure but imperiled in specific states at the edge of its range.

State	S-Rank
TX	SNR

Methodology and Data Sources

Ecosystem classification: Ecosystems are classified using the LANDFIRE 2024 Existing Vegetation Type (EVT) layer, mapped to NatureServe Terrestrial Ecological Systems via a curated crosswalk. Each EVT is linked to the USNVC (U.S. National Vegetation Classification) hierarchy through pixel-level co-occurrence analysis of LANDFIRE EVT and NatureServe IVC Group rasters across all roadless areas.

Vegetation coverage: Coverage percentages and hectares are derived from zonal statistics of the LANDFIRE 2024 EVT raster intersected with roadless area boundaries.

Ecosystem narratives and community species: Sourced from the NatureServe Explorer API, representing professional ecological assessments of vegetation composition, environmental setting, dynamics, threats, and characteristic species assemblages.

IVC hierarchy: The International Vegetation Classification hierarchy is sourced from the USNVC v3.0 Catalog, providing the full classification from Biome through Association levels.

Component associations: Plant community associations listed as components of each NatureServe Ecological System. Association data from the NatureServe Explorer API.

State ranks: Conservation status ranks assigned by NatureServe member programs in each state where the ecosystem occurs.