Illustration by Nancy Klaud
A Case Study
Savanna blazing star is adapted to more shade and disturbance than other blazing stars as a result of its preference for the open, fire-prone oak woodlands it inhabits.
Life History: Perennial
Illinois Status: Rare (not listed)
Populations monitored: 14
Subpopulations monitored: 29
Counties monitored: 3
Savanna blazing star is native to the eastern and midwestern United States. Ranging in height from 2 to 5 feet, the stem has densely arranged alternate, oblong leaves, and is topped with a magenta, spike-like inflorescence. Each inflorescence has 10 to 40 large flowering heads that bloom from the top downward1,2.
Habitat And Range
Savanna blazing star is found from New York southwest to Arkansas, and north into Michigan’s Upper Peninsula. Savanna blazing star is more shade tolerant than other blazing stars, growing in oak savannas, rocky glades, and pine savannas1. In northeastern Illinois, this species is found in remnant savannas on well-drained morainic ridges2,3.
Savanna blazing star blooms from late summer through mid-fall, and is pollinated by numerous butterflies, skippers, and moths. This perennial has a corm-like root that is eaten by rodents and insects1,4. An inhabitant of the now rare tallgrass savanna, it has been shown to compete poorly with big bluestem (Andropogon gerardii), a prairie grass that can form dense rhizomatous colonies. Instead, this species prefers associating with less competitive grasses and bur and white oaks, and benefits from regular disturbance, specifically fire3,4,5.
Midwestern oak savannas experienced a devastating loss of range after European settlement6. Only 0.02% of the original 11 to 13 million hectares were estimated to remain in 19857, and it seems evident that savanna blazing star populations were impacted by this loss of habitat3. Although a number of populations are now protected, loss of habitat through lack of management continues to be a threat. Without management that provides regular disturbance, especially fire, competition with other species can exclude savanna blazing star3,4,5.
After years of taxonomic uncertainty, savanna blazing star was recognized as a distinct variety in Illinois in 19883. The following year it was added to the Illinois threatened species list. In 2015 it was removed from Illinois’s list of endangered and threatened species because it was considered by the Illinois Endangered Species Protection Board to have experienced sufficient recovery or to be more common than previously thought8,9.
Monitoring & Research
Since 2003, POC has monitored this species at 13 sites across three Illinois counties, and at one site in northwest Indiana. These efforts resulted in monitoring of more and larger populations than were previously known. An analysis of management effects and spatial trends was undertaken in 201410. We found that in Cook County alone, 68 percent of the savanna blazing star’s preferred soil type had been developed, but the majority POC-monitored populations were growing over time. This growth seemed related to restoration activities. Growing populations had less brush encroachment than declining populations. And while no strong correlation was found between the frequency of prescribed burning and population growth, populations in decline had not been burned, while all but one growing population had been burned.
Future analysis using POC’s spatial data can identify potentially suitable locations, where soil conditions and land cover could have supported populations historically, or where restoration of this species may be appropriate.
Data collected by Plants of Concern is increasing what we know about how management affects populations, which in turn can help managers more efficiently protect and restore this species. Encouragingly, POC-monitored populations seem to be growing and benefitting from restoration activities, and this trend is reflected in removal of the species from Illinois’ list of threatened and endangered species.
However, these populations are part of the significantly diminished and fragmented oak savanna ecosystem and so suffer from fragmentation themselves. Monitoring by POC can help to detect changes in population trends, and our collaborations with landowners and state agencies will continue ensuring that this data gets to those who need it most.