Education reform calls for portraying science as a process of inquiry and argumentation grounded in the epistemic traditions of a domain. While experimentation is a core scientific investigation strategy, diverse approaches are represented across different domains of science. Ecosystem scientists use experiments as a core part of their investigations, yet also acknowledge limits to its applicability. They describe experimentation as one approach among investigative strategies--combining these into a 'body of evidence' (BOE) approach that triangulates sources of evidence to support causal claims. A study was conducted to explore how these epistemic assumptions in ecosystems science are understood by K-12 teachers. Ten teachers from across the United States were interviewed. The teachers expressed understandings of experimentation that did not fully align with a BOE approach but displayed knowledge of some approaches used by ecosystem scientists. This knowledge was less apparent in their descriptions of their ecosystems science unit pedagogy and curricula and teachers cited a number of obstacles to incorporating it. The results suggest that if a BOE approach were to be introduced in K-12 ecosystems science, teachers would need a fuller understanding of this perspective and support in overcoming obstacles to employing it in the classroom.