A day in the life of the permanently grinning Blanding’s Turtle, a Michigan protected species

A greater understanding of species’ habitat needs points to the importance of keeping the shoreline natural as a way to promote healthy populations of fish and wildlife species and a healthy ecosystem.

Shoreline areas, on land and into the water, provide critical habitat for a variety of fish and wildlife species. Developed shorelines in which natural shoreline vegetation has been removed and replaced to the water’s edge with turf grass or a seawall, may be unable to fully support fish and wildlife species due to habitat destruction and declines in fish and wildlife populations. Such changes can have potential impacts on the health of a lake ecosystem. 

One species that depends on a natural shoreline is the Blanding’s turtle, a medium-sized turtle with a hard-to-miss long bright yellow chin and throat, and a very long neck. Its head is relatively flat with a short, round snout and a notched upper jaw, which give it the appearance of a permanent grin. It has a dome-shaped carapace (top shell) that is usually smooth and black with yellowish spots and streaks. The plastron (underside of shell) is yellow with a dark blotch at the outer corner of each scute, or scale.

With regard to habitat, Blanding’s turtle prefers areas with clean, shallow waters with abundant aquatic vegetation and soft muddy bottoms over firm substrates. It is found in and around ponds, marshes, swamps, and lake inlets and coves. They are sometimes found in rivers. They occupy terrestrial habitats during mating and nesting seasons as well as in the fall. Nesting sites are typically located in uplands adjacent to wetland habitats in sunny areas with moist but well-drained sandy or loamy soil. When suitable nesting habitat is not available, the turtle will settle for lawns, gardens, plowed fields, gravel road, etc. 

According to the Michigan Natural Features Inventory (MNFI) abstract for Blandings’ turtle, the primary threat to Blanding’s turtle is habitat loss, degradation and alteration. Furthermore, the most critical conservation need identified for Blanding’s turtle is the protection and management of suitable wetland and nesting habitat. 

What impacts does a developed shoreline have on species that depend on these areas for some part of their lifecycle? Here are several examples of how the Blanding’s turtle (Emydoidea blandingii) may be impacted:

  • Seawalls and even rock rip rap can disrupt/break the natural transition between the water and land. Blanding’s turtle and other species of turtles, frogs and other animals need to travel between water and land to feed, rest, and nest. Such a vertical or semi-vertical barrier can block or obstruct access to necessary habitats for feeding and reproduction  by making it difficult if not impossible for them to move between land and water.  
  • Many species of fish and wildlife are unable to thrive along sandy swimming beaches or on mowed lawns. Rather, they prefer areas in the water that contain native aquatic plants, bottom materials and natural debris, and trees and shrubs which provide shoreline cover. At night, Blanding’s turtle are also found in or under aquatic vegetation. In addition, when shallow water habitats start to dry up in the summer and fall, some will migrate to another body of water while others enter a state of dormancy or inactivity during hot or dry weather on land by burrowing under roots, mud or plant debris.
  • Removal of “unsightly” fallen trees and shrubs (also called course woody habitat). The Blanding’s turtle has specific requirement for downed woody debris as part of their habitat needed to both sun themselves. When shoreline shrubs and fallen trees are removed from the water’s edge, important turtle habitat is eliminated.  For more ideas on how you can help Blanding’s turtle, visit the Michigan Natural Shoreline Partnership web site for specific ideas on restoring natural shorelines to encourage Blanding’s turtles to frequent shoreline areas. 

MNFI’s Rare Species Explorer is a database containing information on Michigan's 723 rare plants and animals. MFNI also has a large list of species and community abstracts. To find out more about data, programs, services, and educational resources available, visit the MNFI website. 

 “Amphibians and Reptiles of the Great Lakes Region” by James H. Harding is a comprehensive resource on Amphibians and reptiles in Michigan and is available from the University of Michigan Press.  Also visit the Michigan Department of Environmental Quality’s Michigan Turtles web site for additional information. 

For more information on supporting fish and wildlife species on your inland lake shoreline, consult these additional resources:

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