How much do ecosystem engineers contribute to landscape evolution? A case study on Tatra marmots

Abstract Important influences of burrowing animals on ecosystems are reported from several environments. However, the impact of burrowing on alpine meadows has only been poorly studied. The largest and most widespread burrowing animals living in an alpine region are marmots. We tried to answer the following questions: Do marmots cause structural and compositional changes in alpine plant communities? Do marmots have a significant effect on soil properties? Do vegetation types differ according to their dependency on the functional utilization of the burrow? On a colony scale marmots significantly increased cover of herbs on next-to-burrow mound plots as opposed to on burrow and control plots, while they decreased cover of graminoids, lichens, and litter, which were the highest on sites without marmot activities. Equitability increased gradually in direction from controls, next-to-burrow mound plots to burrow plots. Simultaneously, marmots increased N, Mg and K on next-to-burrow mound plots as opposed to on burrow and control plots. Biopedturbation by marmots contributes to creating the gradient of vegetation between marmot free meadows and disturbed habitats. Tatra marmots encourage settlement of moisture and light-demanding plants with larger requirements for soil depth on their burrow mounds. On next-to-burrow mound plots they support acidophilous vegetation with grazing- and trampling-resistant or grazing-tolerant species. A considerable higher content of P was present directly on the mounds compared to next-to-burrow mound plots. Marmot activities alter soil properties, reduce the dominance of common species and thereby enhance community diversity. Their effects, depending on the volume and nature of their activities, are the strongest on hibernation and maternal burrows and their surroundings. Our results demonstrate the key role of environment-marmot interactions in alpine ecosystems and landscape development.