A monarch butterfly on milkweed.

A reported 85 percent decline in the overwintering monarch butterfly’s western population from 2017 to 2018 prompted the USDA Natural Resources Conservation Service in Idaho to remind farmers of the financial and technical resources is has available for conservation projects.

The Xerces Society for Invertebrate Conservation said the abrupt one-year decline left the western monarch population at less than 1 percent of 1980s levels. The population has been declining since the 1980s — in part because of decreases in native plants such as milkweed, on which monarch caterpillars feed.

In a report, Xerces said low estimates for 2018 were foreshadowed by reports of low numbers of the western monarch breeding population observed in western states in the summer and in preliminary Thanksgiving count data.

“The drop between the 2017 and 2018 counts may be attributable to late-season storms and a severe wildfire season in California and elsewhere in the West,” the report said.

“With the monarch butterfly’s western population in peril, we’re encouraging our Idaho producers to work with their local USDA Service Center and Soil and Water Conservation District on how to implement pollinator habitat practices into their operation for the benefit of our beloved monarch butterflies,” Curtis Elke, Idaho state conservationist with NRCS, said in a release. “NRCS offers more than three dozen conservation practices that enable producers to help monarchs and other pollinators as well as benefit their agricultural operations.”

Part of the cost may be covered through the Environmental Quality Incentives Program and other farm bill-funded programs, NRCS said.

Planting nectar plants to sustain butterflies and milkweed to feed caterpillars can help give monarchs the best chance of recovery, according to Xerces. NRCS recommends Idaho producers establish plants that bloom in late summer and early fall as monarchs leave the region to return to overwintering sites along the California coast.

NRCS said that while many conservation practices it recommends may target improving grazing lands or reducing soil erosion, simple changes to plant selection and how management practices are timed can help monarchs substantially.

field reporter, SW Idaho and SE Oregon

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