Montana Field Guide

Asclepias incarnata is rare in Montana where it occurs only in the south-central portion of the state. Populations in Carbon County are considered native. Populations growing in vicinity of residential and agricultural areas are likely originating through seed dispersal from ornamental or garden plantings. At least one sub-population in Carbon County was lost prior to 2005 from renovations designed to prevent Whirling Disease at the Bluewater Fish Hatchery, managed by Montana Fish, Wildlife & Parks (MFWP). Native populations continue to face potential threats from possible future renovations at the fish hatchery as MFWP creates barriers to prevent introductions of non-native animals, such as the New Zealand Mud Snail. Both native and accidental introductions of Asclepias incarnata face threats from non-native perennial grasses and noxious weeds, and incompatible land management actions where plants grow in natural areas encroached upon by development. In addition, shifts in climate may negatively impact Asclepias incarnata over the next decade or longer, particularly from the effects of increased temperatures, increased frequency and severity of droughts, and/or decreased snowpack. However, impacts from a shifting climate remain unknown. Surveys that bring forth current information on population counts, habitat quality, and assess for threats at native populations are greatly needed. Surveys are also needed in areas modeled as Predicted Suitable Habitat. Developing collaborative conservation agreements with state land managers and private landowners are needed to ensure the persistance of Asclepias incarnata, particularly native populations. Implementing monitoring of populations at and near the Bluewater Fish Hatchery is necessary to also assess short- and long-term population trends.