Are foundation species effects different than those of dominant species? A case study of ant assemblages in northeastern North American forests

Foundation species uniquely control associated biodiversity through non-trophic effects, whereas dominant species are locally abundant but are replaceable in ecological systems. Long-term data on ant assemblages at the Harvard Forest Hemlock Removal Experiment (HF-HeRE) and the Black Rock Future of Oak Forests Experiment (BRF-FOFE) provide insights into how ant assemblages change and reassemble following the loss of a foundation species ( Tsuga canadensis ) or a dominant genus ( Quercus ). At HF-HeRE, removal of T. canadensis trees resulted in taxonomic and functional shifts in ant assemblages relative to control stands. In contrast, ant assemblages at BRF-FOFE varied little regardless of whether oaks or non-oaks were removed from the canopy. Non-trophic effects of foundation species were stronger than indirect trophic effects on taxonomic and functional diversity of ant assemblages. In contrast, non-trophic effects of dominant species were weaker than indirect trophic effects on ant taxonomic diversity and some measures of ant functional diversity. Statement of authorship A.M. Ellison and S. Record conceived the study. A.M. Ellison, T. 17 McCabe, and S. Record collected field data. T. McCabe and S. Record did the taxonomic diversity analyses. B. Baiser and S. Record did the functional diversity analyses. All authors contributed to drafts of the manuscript. Data accessibility All data ( i.e. , ant and trait) and R code are available from the Harvard Forest Data Archive ( http://harvardforest.fas.harvard.edu/data-archive ), datasets HF-118 (HF-HeRE) and HF-097 (BRF-FOFE). Nomenclature follows Bolton (2016); voucher specimens are stored at the Harvard Forest and at the Museum of Comparative Zoology.