MNFI soil, vegetation, tree, and wildlife crosswalk, 2017

Summary

This crosswalk connects the physical and biological parts of the Beaver archipelago record without pretending they were collected at the same scale. It preserves all 43 natural-community occurrence records in the 2017 MNFI report, including direct statements about soil, hydrology, tree composition, tree age, wildlife, birds, disturbance, and management. It then attaches the current SSURGO crosswalk by named island so researchers can compare the source vocabularies while keeping occurrence boundaries separate from soil-map-unit boundaries.

The MNFI records cover four islands: Beaver (17 occurrences), Garden (12), High (8), and Hog (6). North Fox, South Fox, and Whiskey remain in the wider SSURGO and biodiversity research frame, but they do not have MNFI occurrence records in this particular report. That absence is a source-coverage fact, not evidence that those islands lack the community types or species.

Soil and habitat structure

The strongest result is that the report repeatedly describes ecological communities as transitions among substrate, water, shoreline process, and vegetation—not as isolated tree lists. The table counts occurrence records with a direct source mention; it does not count acres or abundance.

Several patterns are especially useful for joining the soil and geology work to the ecology record:

• Beaver’s bogs and poor fen are peat-on-sand or peat-on-lakeplain systems in which acidity, saturation, inundation, and groundwater influence determine the vegetation zones.
• Garden and Hog coastal fens and northern fens are alkaline peat/marl/sand or peat-mat systems. Their chemistry and water levels are part of the habitat evidence for Hine’s emerald dragonfly and crayfish burrows.
• Boreal forests are not one soil type. The report contrasts acidic sands and former sand shore with alkaline loams or loamy organics over limestone cobble; the substrate contrast accompanies shifts in cedar, pine, spruce, and hardwood dominance.
• Dune and beach communities are process-driven. Moving sand, wind, waves, and ice keep active beaches open, while stabilized ridges and swales support scattered trees, wetland pockets, and more complex forest mosaics.

Tree types, ages, and regeneration

The most frequently directly named tree in the four-island MNFI record is northern white-cedar, followed by white pine, balsam fir, paper birch, tamarack, red maple, hemlock, black spruce, red pine, white spruce, yellow birch, red oak, sugar maple, white ash, and black ash. These counts describe how many surveyed occurrences mention a tree in the preserved facet text; they are not a regional inventory or abundance ranking.

The report also preserves a useful age and disturbance sequence:

These ages are individual cores or estimates within named occurrences, not dates for an entire stand. Windthrow, fire, selective logging, beaver flooding, coarse woody debris, and deer browse recur throughout the report. On Beaver, the report repeatedly interprets missing yew or hemlock regeneration and browsed saplings as possible deer effects. High Island’s absence of deer is explicitly treated as a comparison opportunity, not as a universal ecological condition.

Animals, birds, and habitat connectivity

The report’s animal evidence is habitat-linked and unevenly distributed:

• Indian Harbor on Garden Island is described as important for fish spawning and used by diverse shorebirds and secretive marsh birds. The 2017 survey observed two American bitterns; Odawa DNR marsh-bird surveys documented Virginia rail and sora there.
• Hine’s emerald dragonfly is reported as a population at Jensen Harbor and as apparent suitable habitat at several other fen sites. The crosswalk preserves those distinctions rather than converting every “suitable habitat” statement into a confirmed occurrence.
• Pitcher’s thistle is repeatedly associated with Beaver and High Island dune, barrens, interdunal, and beach-margin records. High Island’s open-dune record also names Lake Huron locust.
• Deer trails, browse, and likely winter-deer-yard use recur in Beaver’s boreal and rich-conifer systems and appear in records from High and Hog. Beaver activity or flooding is documented at several wetland and forest margins.
• Driftwood and plant debris on limestone cobble shores are described as habitat for insects and herptiles and as material for soil development.

The ecological bridge is therefore a chain rather than a single classification:

substrate and water regime -> natural community -> tree/plant structure -> wildlife habitat and disturbance

The machine-readable crosswalk retains the sentences at each link, along with report pages and source line ranges, so later mapping can test candidate relationships instead of silently turning them into facts.

SSURGO island context

The crosswalk attaches the current SSURGO results to the same named-island frame. This makes comparisons such as “Beaver’s MNFI occurrences and its current map-unit vocabulary” possible, but it does not claim that a soil unit intersects a particular MNFI occurrence. Fox Islands and Whiskey Island remain visible through the soil and biodiversity layers even though this MNFI report has no occurrence records for them.

The current SSURGO labels are a later mapping generation than the 2017 MNFI field descriptions and the 1974 county survey. Shared words such as sand, beach, dune, peat, loam, and cobble are useful search bridges, not proof of one-to-one map-unit equivalence or occurrence overlap.

Evidence limits and next research

The MNFI report surveyed selected natural-community element occurrences, not all land or all species. The normalized terms are exact substring matches to source-preserved facet sentences. Reported acres are sums of occurrence sizes and may not be additive or comparable to island area. Rare and sensitive sites remain at source-level granularity without new coordinates. The next useful step is a geometry-aware comparison where authoritative occurrence boundaries, SSURGO polygons, NWI wetlands, circa-1800 cover, and current forest layers are available together; until then, this crosswalk should remain a record of documented associations, not a habitat prediction model.

Added 3 August 2026. Recent changes