Causal impact of fire on a globally rare wetland plant: a 40-year Bayesian time series analysis

Abstract Background Canby’s dropwort ( Oxypolis canbyi (J.M. Coult. & Rose) Fernald) was listed as federally endangered in 1986, yet the species has continued to decline and is no longer found 11 counties throughout its former range. The seasonal wetlands which this forb occurs are disappearing from landscape, often closing transitioning wet forest or drained converted agriculture. We document effects of reintroducing fire only population O. Maryland examine resulting increase using Bayesian interrupted time series analysis with a counterfactual. Results After cutting woody vegetation, 3.74 times more stems per year were produced over baseline intervention. Subsequently, after reintroduced, 10.80 comparison period vegetation. counterfactual prediction showed that absence intervention fire, stem production would likely have declined. Conclusions Cutting vegetation set stage for growth fine fuels by increasing sun exposure on wetland grasses. It reintroduced plants expanded significantly extent flower production. A process model selection directed acyclic graph followed useful causal inference. Application an important step recovery dropwort.