Pitcher's thistle is one of more than 400 native flowering plants on a list of threatened species in Michigan. Photo: US FWS
What botanists might consider the fairest may be the rarest in Michigan.
Flowering plants top a list of extremely rare species groups in an analysis of endangered, threatened, extinct and special concern animal and plant species.
They outnumber similar species in mammal, amphibian, reptile, fern and other groups by nearly two to one.
But what is rare in Michigan may not be in other states or globally.
“The vast majority of our flora is decidedly common outside Michigan,” said Michael Penskar, the lead botanist for the Michigan Natural Resources Inventory, a group that tracks rare species.
Michigan contains the edges of larger populations of plants that aren’t exclusively Michiganders–much of their population may lie in neighboring states where the plants don’t even make the rare species list.
Flowering plants aren’t necessarily in danger because there are more rare species in the state, either.
Penskar said there are more plant species on the inventory’s list because there are more plant species than animal species.
Michigan supports 2,700 to 2,800 different plant species.
“So if you have more to begin with, you’re going to have more that will be affected by human settlement and the like,” Penskar said.
But that isn’t a reason to stop work to conserve them.
“We should be concerned about what’s rare in our state regardless of if it’s very common…because that mix of species is part of our natural heritage,” Penskar said.
Monkey flower faces extinction
More than 400 of Michigan’s 1800 native flowering plants are on the inventory’s list.
Those facing extinction tend to be the most finicky, like the Michigan monkey-flower.
“That’s the rarest of the rare for Michigan,” Penskar said.
A perennial with tubular yellow flowers, the monkey-flower is only found in 12 isolated populations throughout Michigan. Penskar penned the monkey-flower’s 1997 recovery plan after it obtained endangered species designation in 1990.
The plant is endemic–it has a narrow and specific range that includes the Mackinac Straits and Grand Traverse regions, according to a U.S. Fish and Wildlife Service document.
But the monkey-flower remains rare in Michigan because it’s picky–it likes sticky, sandy soils near streams and lakes. All known populations are associated with the Great Lakes shorelines. There, the monkey-flower only likes cold, flowing spring water.
But with such specific needs, the monkey-flower’s greatest threat is habitat destruction and conversion. Off-road vehicles turn up the soil and destroy habitat. The lure of lakefront property has also left the monkey-flower in the dust as development progresses.
Off-roading rough on Hall’s bulrush
Habitat destruction along shorelines has also proved to be a problem for Hall’s bulrush. Off-roading activity often increases when waters recede and create muddy conditions in its habitat, said Brad Slaughter, an inventory botany conservation associate.
“They look really ugly and scarred when that happens, especially when they’re wet and you just end up with huge wheel ruts,” he said.
And like the monkey-flower, Hall’s bulrush prefers its own specialized pad. Penskar thinks the bulrush could become the new monkey-flower in Michigan.
Hall’s bulrush is found in coastal plain marshes that aren’t very common. It occurs in southwest Michigan, northern Indiana and a part of Illinois.
The marsh type it prefers is also specialized–it’s characterized by draw-down lakes or ponds, Slaughter said.
“Usually in the late winter, early spring it looks like a lake or a pond but by the end of summer there’s no inlet or outlet to these systems. They’re pretty much just fed by the water table and precipitation so it’ll just draw right down and be dry,” he said.
Some sites can remain dry for more than 10 years. Correlated with Great Lakes water levels and additional precipitation, these wetlands and pools become wet again.
“The plants that grow in these systems have to be adapted to basically cycles of inundation and then what we call desiccation, or just drying,” Slaughter said.
Hall’s bulrush can be elusive, though.
“It might not even appear above the ground until conditions are right,” Slaughter said.
Instead, Hall’s bulrush remains in a seed state. Slaughter said bulrush was last sighted in Michigan in 2002 and suddenly showed up in 2008-2009.
Changes in groundwater or precipitation due to climate change could also spell trouble for the bulrush.
Plans for Pitcher’s thistle
But not all stories end with extinction.
Recovery plans for Pitcher’s thistle were completed in 2002, though efforts to save the dune dweller began before then, said Tameka Dandridge.
Dandridge is a U.S. Fish and Wildlife Service wildlife biologist who organizes agencies to implement recovery plans.
There are many populations of the thistle in Michigan, Indiana, Wisconsin and Ontario, Canada. But Pitcher’s thistle is only found on shorelines or Great Lakes sand dunes.
Dandridge said the fragmented locations of populations make monitoring key to ensuring they don’t disappear.
She also said habitat destruction by off-road vehicles and invasive species are two factors that threaten the species.
The thistle doesn’t produce seeds for more than five to 10 years. The seed is large and typically lands near the parent plant because it can’t travel on wind.
Continuing recovery plans in each state, better landowner awareness of the plant’s needs and occurrences, along with hopes for continued monitoring to discover new populations and assess old ones could delist this species soon, Dandridge said.
Help often comes too late
But Slaughter said the situation is not ideal. He said society tends to focus on those species that decrease and once a site requires actual care, it’s more than likely functioning at a non-sustainable level.
“It’s a bad sign for the environment,” he said. “They’re so degraded and fragmented that if we do nothing, they’ll just go away. Even if we do something we might just buy them more time.”
Sometimes managers do find a management technique that turns habitats around.
“There are those moments, just kind of like the stars in the night sky,” he said.
And Penskar witnesses far more discoveries than wink outs on his watch.
“We continue to find (new plant populations) in this state,” he said.
group, common and scientific names and habitat types in which they were found.