Post-fire recovery and resilience of benthic macroinvertebrate communities in streams of a ponderosa pine forest

During summer 2011, New Mexico’s Lincoln National Forest experienced severe drought and intense wildfires affecting approximately 400,000 acres of forest, leaving large sections in ashes and causing forest closures to the public. Physical alterations, changes in alkalinity, nutrient concentrations, turbidity and dissolved oxygen as consequences to wildfires can be deleterious to aquatic macroinvertebrate communities. In this study we examined changes in macroinvertebrate community composition along a time-since-fire gradient. Macroinvertebrates were collected using kick-nets and D-frame nets for five months (May to September) and identified to genus; water samples were analyzed for nutrients and total organic carbon (TOC) using standard methods. Sampling efforts from 2011 yielded community assemblage data for reference (non-burned) sites; shredders accounted for only 10% of relative functional feeding group abundance, which may indicate a weak dependence on allochtonous inputs. A greater proportion of scrapers (19%) suggests greater dependence on algae, which likely grow well in these streams that are surrounded by grasses and forbs and thus relatively unshaded.  We hypothesize that the adjacent grasslands may be buffering the effects of fire on nearby streams by minimizing burnt organic matter inputs and allowing invertebrate dietary preferences to remain relatively unchanged. Samples will be collected in 2012 to confirm this trend. This study will provide a platform for future research regarding the impacts of fire on biological communities and contribute to our understanding of ecological succession in aquatic ecosystems post-fire.