Isle au Haut
Isle au Haut
Description: 
Named "the high island" by French explorer Samuel de Champlain in 1604, the 4700-acre Isle au Haut is a granitic offshore island with several rugged hills, narrow valleys, and small wetlands.  Isle au Haut and surrounding smaller islands support a variety of maritime habitats and species in a remote and largely undisturbed setting.  The juxtaposition of maritime habitats around the island's perimeter with xeric interior habitats results in a convergence of natural communities with both boreal and southern affinities.  Few other locations in Maine support coastal plateau bogs, coastal headlands, and pitch pine woodlands.  
	
The eastern edge of the island has numerous small, linear wetlands.  At just over 20 acres, the Great Meadow is one of the island's few open wetlands.  It is a sedge-leatherleaf fen lawn that supports the rare ink-berry (Ilex glabra) and screwstem (Bartonia paniculata) as well as a large population of the uncommon dragon's mouth (Arethusa bulbosa).  In fact, Isle au Haut is the state's only known location of ink-berry (Ilex glabra), a plant more typical of the coastal plain of Massachusetts and Rhode Island.  Moreover, thirteen of the state's fifteen extant populations of screwstem are located on the island. 
	
From Duck Harbor in the southwest to Champlain Mountain in the northeast, ridges along the central spine of the island have thin soils and patchy forest development.  A few locations support intact, fire-adapted pitch pine woodlands underlain by a carpet of the uncommon broom-crowberry (Corema conradii).  These pitch pine woodlands are among the northern-most in Maine.  Red and black spruce (Picea rubens and P. mariana) are common associates.  It is likely that the fires of 1947 influenced these woodlands, although some cored trees (e.g., one aged at 170 years) clearly pre-date the fires.   
	
Coastal headlands occur at various locations on Isle au Haut - most notably Eastern Head, Western Head, and Duck Harbor.  Headlands on Isle au Haut and surrounding smaller islands support maritime species such as blinks (Montia fontana) and dwarf rattlesnake root (Prenanthes nana). 

Isle au Haut supports four bald eagle essential habitats, and nearby islands support several more. About 200 harlequin ducks winter primarily along the southern shore of Isle au Haut between Eastern Head and Western Head. Harlequin ducks feed on amphipods and other intertidal invertebrates on the wave-exposed shoreline. An additional 200-300 harlequins winter in similar habitats of surrounding islands including The Cowpen, Little Spoon, Great Spoon and York. About 50-100 pairs of common terns-an uncommon species in Maine-nest on Isle au Haut and these nearby islands as well. Isle au Haut and surrounding islands also provide significant winter habitat for purple sandpipers. Recent surveys have observed over 2000 purple sandpipers feeding and roosting in this area.


Rare Species and Exemplary Natural Community Table for Isle au Haut:
	
Common Name

Latin Name

S-RANK

G-RANK
State Status

Exemplary Natural Communities
Pitch Pine Woodland
S3
G2?
N/A
Lower Elevation Spruce - Fir Forest
S4
N/A
N/A
Sedge Heath Fen
S4
N/A
N/A
Leatherleaf Bog
S4
N/A
N/A

Rare Plants
Screwstem
Bartonia paniculata
S1
G5
T
Swarthy sedge
Carex adusta
S1
G5
E
Wiegand sedge
Carex wiegandii
S3
G3
SC
Appalachian fir-clubmoss
Huperzia appalachiana
S2
G4G5
SC
Ink-berry
Ilex glabra
S1
G5
T
Mountain sandwort
Minuartia groenlandica
S3
G5
SC
Blinks
Montia fontana
S2
G5
SC
Water awlwort
Subularia aquatica
S2
G5
SC
Dwarf rattlesnake root (historic)
Prenanthes nana
S1
G5
E
Canada mountain rice-grass (historic)
Oryzopsis canadensis
S1
G5
SC
Beach plum (historic)
Prunus maritime
S1
G4
E
Dudley's rush (historic)
Juncus dudleyi
S2
G5
SC

Rare Animals
Wood turtle
Clemmys insculpta
S4
G4
T
Bald eagle
Haliaeetus leucocephalus
S4
G4
T
Harlequin Duck
Histrionicus histrionicus
S2S3
G4
T


Other Habitats Mapped by MDIFW: 
Freshwater Waterfowl / Wading Bird Habitat
Tidal Waterfowl / Wading Bird Habitat
Bald Eagle Essential Habitat

Conservation Considerations:
* The majority of the island is within Acadia National Park, and disturbance is limited to trail use and a few campsites.  Outside of the park, the northwestern part of the island has the only village.  Summer homes are sparsely scattered around other privately-owned coves on the island.  A single road forms a perimeter around all but the southern-most tip of the island.  

* While old pasture fences and old field succession attest to former agricultural uses within the Park boundaries, natural disturbances such as fire and wind have likely been the dominant influences within the past 75 years.  

Protection Status:
Acadia National Park owns 3,272 acres on the island and holds conservation easements on 598 acres of surrounding islands.  The Nature Conservancy holds 65 acres of easements on nearby islands.  MDIFW owns and manages Great Spoon Island and The Cowpen (east and west islands).