Trillium foetidissimum

The primary threat impacting Mississippi River Trillium is habitat loss and degradation due to logging, silviculture, and urban sprawl (NatureServe 2019). Disruption of fire regimes within the species’ range have been demonstrated to negatively impact herbaceous understory species frequency, though the specific impact on Mississippi River Trillium has not been studied (Reeves 1970). The species is a host to Sclerotinia sclerotiorum and may be impacted by nearby infected crops or persecution in efforts to control spread of the disease (Holcomb 1990). Excessive herbivory due to overabundance of White-tailed Deer (Odocoileus virginianus), a threat observed in several other Trillium species (Augustine and Frelich 1998, Jenkins et al. 2007, Knight et al. 2009),  is likely to also impact Mississippi River Trillium. White-tailed Deer overabundance is common throughout the eastern United States (Russell et al. 2001) and is promoted by several land use patterns evident in the species’ range including forest fragmentation, silviculture operations, and the presence of adjacent urban and agricultural areas. The specific impact of white-tailed deer overabundance on Mississippi River Trillium is currently poorly understood, but is likely to contribute to ongoing population declines. Feral hogs (Sus domesticus), which occur within the species’ range, have a negative impact on other Trillium species and likely lead to localized population declines in Mississippi River Trillium (Bratton 1974). Chinese Privet (Ligustrum sinense) may threaten the species in some parts of its range. Overall population is thought to be declining, but precise figures on the rate or cause of this decline are unavailable (NatureServe 2019).

Though not specifically protected at the federal or state level, the species may occur incidentally in several protected areas within its range (IUCN and UNEP-WCMC 2019). Additional monitoring of subpopulations and habitat status are necessary as the species is not currently monitored by natural heritage programs in Louisiana or Mississippi. Remediation of favourable habitat throughout the species’ range could be accomplished by reinstating natural fire regimes promoting understory growth. The species is included in ex situ collections at nine botanic garden sites (BGCI 2019).