Colorado mountains
From Long-Term Data to Understanding: Toward a Predictive Ecology
2015 LTER ASM Estes Park, CO - August 30 - September 2, 2015

Fossorial Animals Modify Vegetation Recovery Following Wildfire in Grassland, Sevilleta LTER

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Presenter/Primary Author: 
Nancy Nicolai

Patches are important elements in communities perhaps influencing vegetation recovery following large-scale distrubances.  Banner-tail kangaroo rat (Dipodomys spectabilis) and rough harvester ant (Pogonomyrmex rugosus) are soil engineers creating 1-15 m nest patches of improved soil conditions and resources.  In semiarid grasslands of Sevilleta LTER, these patches differ from surrounding vegetation.  Kangaroo rat patches are dominated by forbs and harvester ant patches by grasses.  I explored the direction of plant functional group recovery from the combined influence of: fire, nest patches, and two animal species.  Animal patches strongly affect recovering vegetation 2 years following fire.  In contrast to unburned patches, kangaroo rats facilitated grasses whereas harvester ants augmented forbs after fire.  Compared to nonpatches, burned treatments had greater grass productivity and density on rat patches perhaps due to better resources for recovery, including unique soil biota.  Productivity increased on ant patches compared to nonpatches and this difference is greater in burned vs. unburned treatments, thus patch resources amplify fire pulse.  Plant richness increased on both species' burned patches thus when fire removes biomass, subdominant species can utilize patch resources.  Plants on patches bear more inflorescences; maybe patches are foci for seed dispersal during recovery.  The role of nest patches in vegetation recovery is an interaction among fire pulse, biomass removal, and the unique patch resources of each animal.