Plants

This spring-blooming herbaceous perennial, Hepatica can be found flowering well before other woodland wildflowers.

NPS/DPeterson

The St. Croix National Scenic Riverway consists of three major biomes - prairie, deciduous hardwood forest, and northern coniferous forest - that intersect to create a rich yet fragile diversity of habitats for plants and animals. Plants protect the linear nature of the Riverway by providing refuge and a corridor for movement for a diversity of wildlife.

Vegetation on the rocky gorge of the Dalles of the St. Croix is relatively sparse and dry. Numerous exposures of rounded rock, cliffs, and boulders are barren, while similar sites with greater moisture are home to numerous ferns, mosses, and lichens. Dry forest containing red cedar, basswood, white pine, and bur, white, and black oaks occur throughout the Riverway.

Silver Maple is the dominant canopy species in the floodplain forest and river backwaters channels, along with green ash, hackberry, and American elm. Basswood, red oak, cottonwood, black willow, and bitternut hickory also are present in small numbers. The surrounding upland forest contains oak, basswood, big-tooth aspen, paper birch, and an occassional white pine. Scatters patches of prairie and savanna vegetation can be found. Along steep river banks often contain seepages that harbor large populations of the state-endangered bog bluegrass. Shallow water areas contain abundant bulrush, rice cut grass, and prairie cord grass.

Native habitats are susceptible to non-native plants such as common buckthorn, prickly-ash, garlic mustard, purple loosstrife, nodding thistle, and others.

Non-native Plants
A wide variety of plants introduced by humans to the North American landscape can create problems in the park as these non-native species crowd out native plants and threaten the ecosystem.

Guide to common invasive plants of the Northern Great Plains including St. Croix National Scenic Riverway.

More information

• Tackling Invasive Plants in Our National Parks

 

×

Species Attribute Definitions

Definitions

Occurrence

Occurrence values are defined below. One or more Occurrence Tags may be associated with each Occurrence value.

Present: Species occurs in park; current, reliable evidence available.

Probably Present: High confidence species occurs in park but current, verified evidence needed.

Unconfirmed: Species is attributed to park but evidence is weak or absent.

Not In Park: Species is not known to occur in park.

---

Occurrence Tags

Adjacent: Species is known to occur in areas near to or contiguous with park boundaries.

False Report: Species was reported to occur within the park, but current evidence indicates the report was based on misidentification, a taxonomic concept no longer accepted, or other similar problem of error or interpretation.

Historical: Species' historical occurrence in park is documented. Assigned based on judgment as opposed to determination based on age of the most recent evidence.

---

Abundance

Abundant:

• Animals: May be seen daily, in suitable habitat and season, and counted in relatively large numbers.
• Plants: Large number of individuals; wide ecological amplitude or occurring in habitats covering a large portion of the park.

Common:

• Animals: May be seen daily, in suitable habitat and season, but not in large numbers.
• Plants: Large numbers of individuals predictably occurring in commonly encountered habitats but not those covering a large portion of the park.

Uncommon:

• Animals: Likely to be seen monthly in appropriate habitat and season. May be locally common.
• Plants: Few to moderate numbers of individuals; occurring either sporadically in commonly encountered habitats or in uncommon habitats.

Rare:

• Animals: Present, but usually seen only a few times each year.
• Plants: Few individuals, usually restricted to small areas of rare habitat.

Occasional:

• Animals: Occurs in the park at least once every few years, varying in numbers, but not necessarily every year.
• Plants: Abundance variable from year to year (e.g., desert plants).

Unknown: Abundance unknown

---

Nativeness

Native: Species naturally occurs in park or region.

Non-native: Species occurs on park lands as a result of deliberate or accidental human activities.

Unknown: Nativeness status is unknown or ambiguous.

×

List Differences

The Checklist contains only those species that are designated as "present" or "probably present" in the park.

The Full List includes all the checklist species in addition to species that are unconfirmed, historically detected, or incorrectly reported as being found in the park. The full list also contains species that are "in review" because their status in the park hasn't been fully determined. Additional details about the status of each species is included in the full list.

The checklist will almost always contain fewer species than the full list.

Select a Park:

Saint Croix National Scenic Riverway

Select a Species Category (optional):

All Amphibians Birds Fish Mammals Reptiles Vascular Plants

Get Checklist Get Full List List Differences

Species attribute definitions

Search results will be displayed here.

Visit NPSpecies for more comprehensive information and advanced search capability. Have a suggestion or comment on this list? Let us know.