Pacific Northwest Landslide Forest

EVT 7063North Pacific Broadleaf Landslide Forest
CES204.846GNRTreeHardwood
Summary
These forests and shrublands occur throughout the northern Pacific mountains and lowlands, becoming less prominent in the northern half of this region. They occur on steep slopes and bluffs that are subject to mass movements on a periodic basis. They are found in patches of differing age associated with different landslide events. The vegetation is deciduous broadleaf forests, woodlands, or shrublands, sometimes with varying components of conifers. Alnus rubra and Acer macrophyllum are the major tree species. Rubus spectabilis, Rubus parviflorus, Ribes bracteosum, and Oplopanax horridus are some of the major shrub species. Shrublands tend to be smaller in extent than woodlands or forests. Small patches of sparsely vegetated areas or herbaceous-dominated vegetation (especially Petasites frigidus) also often occur as part of this system. On earthflows, once stable, vegetation may succeed to dominance by conifers.
Source: NatureServe Explorer
Distribution
This system occurs throughout the northern Pacific mountains and lowlands (latter especially adjacent to coastlines), becoming less prominent in the northern half of this region.
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 macrophyllum

Shrub/sapling (tall & short)

Alnus rubra, Oplopanax horridus, Ribes bracteosum, Rubus parviflorus, Rubus spectabilis

Herb (field)

Cardamine pattersonii, Erigeron howellii, Erythronium elegans, Filipendula occidentalis, Lasthenia macrantha ssp. macrantha, Oenothera wolfii, Petasites frigidus, Phacelia argentea, Sidalcea hirtipes
Source: NatureServe Ecological System assessment
Ecologically Associated Animals (13)

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.

Mammals (5)

Common NameScientific NameG-Rank
Long-tailed VoleMicrotus longicaudusG5
American ErmineMustela richardsoniiG5
Long-tailed WeaselNeogale frenataG5
Townsend's ChipmunkNeotamias townsendiiG5
North American DeermousePeromyscus maniculatusG5

Reptiles (2)

Common NameScientific NameG-Rank
Northwestern GartersnakeThamnophis ordinoidesG5
Common GartersnakeThamnophis sirtalisG5

Amphibians (1)

Common NameScientific NameG-Rank
Oregon Slender SalamanderBatrachoseps wrightiG3

Molluscs (5)

Common NameScientific NameG-Rank
Evening FieldslugDeroceras hesperiumG2Q
Tillamook WesternslugHesperarion mariaeG3
Pacific SidebandMonadenia fidelis flavaG4G5T1T2
Broadwhorl Tightcoil SnailPristiloma johnsoniG3
Scarletback Taildropper SlugProphysaon vanattaeG4G5
Source: NatureServe Ecological System assessment
At-Risk Species Associated with this Ecosystem (13)

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 NameScientific NameG-RankESA Status
Oregon Slender SalamanderBatrachoseps wrightiG3--
Saddle Mountain BittercressCardamine pattersoniiG2--
Evening FieldslugDeroceras hesperiumG2Q--
Howell's FleabaneErigeron howelliiG2--
Coast Range FawnlilyErythronium elegansG2--
Queen-of-the-ForestFilipendula occidentalisG2G3--
Tillamook WesternslugHesperarion mariaeG3--
Perennial GoldfieldsLasthenia macrantha ssp. macranthaG3T2--
Pacific SidebandMonadenia fidelis flavaG4G5T1T2--
Wolf's Evening-primroseOenothera wolfiiG2--
Silvery PhaceliaPhacelia argenteaG2Threatened
Broadwhorl Tightcoil SnailPristiloma johnsoniG3--
Bristly-stem SidalceaSidalcea hirtipesG2--
Source: NatureServe Ecological System assessment
Component Associations (1)

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.

NameG-Rank
Acer macrophyllum - Alnus rubra / Polystichum munitum - Tellima grandiflora ForestG2 NatureServe
State Conservation Ranks (2)

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.

StateS-Rank
ORSNR
WASNR
Roadless Areas (8)

Inventoried Roadless Areas where this ecosystem is present, identified from LANDFIRE 2024 Existing Vegetation Type spatial analysis. Coverage indicates the proportion of each area occupied by this ecosystem type.

Oregon (3)

AreaForestCoverageHectares
Hebo 1aSiuslaw National Forest8.3%465.3
Drift CreekSiuslaw National Forest2.2%57.33
LarchMt. Hood National Forest1.5%76.59

Washington (5)

AreaForestCoverageHectares
Silver StarGifford Pinchot National Forest2.6%80.28
BourbonGifford Pinchot National Forest1.7%30.42
Higgins MountainMt Baker-Snoqualmie National Forest1.5%79.83
Spencer RidgeGifford Pinchot National Forest1.5%34.92
Bear CreekGifford Pinchot National Forest1.1%34.11
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.