Spatial pattern and composition of the <scp>F</scp>lorida scrub seed bank and vegetation along an anthropogenic disturbance gradient

Abstract

Abstract Question How does spatial pattern and composition of the seed bank and its relationship to above‐ground cover vary across an anthropogenic disturbance gradient of intact F lorida rosemary scrub, degraded scrub and improved pasture? Location F lorida rosemary scrub, L ake W ales R idge, H ighlands C ounty, FL , USA (27° 11′N, 81° 21′W). Methods In nine grid plots located in intact F lorida rosemary scrub, degraded scrub and improved pasture, we assessed percentage vegetation cover and seed bank composition. Results The vegetation was dominated by long‐lived perennials, while the seed bank was dominated by short‐lived species. Shrubs were the dominant above‐ground cover in rosemary scrub, sub‐shrubs and the spike moss S elaginella arenicola in degraded scrub and non‐native grasses in pastures. Scrub forbs were dominant in the seed bank of rosemary scrub, similar amounts of sedges, ruderal forbs and scrub forbs in degraded scrub, and ruderal species and sedges in pastures. Species absent from the vegetation were randomly distributed in the seed bank, while species present above‐ground had an aggregated spatial distribution. In rosemary scrub, scrub forb seed banks were spatially aggregated and were positively associated with conspecific species above‐ground and with litter cover. These patterns were not observed in degraded scrub, perhaps due to reduced shrub and increased bare ground. Conclusion Our results suggest that reduced shrub cover and increased bare ground in the degraded scrub may explain why there is less spatial aggregation of scrub forbs in the seed bank. Restoration of F lorida rosemary scrub in pasture sites will require species reintroduction of appropriate scrub species; restoration of degraded scrub should emphasize increasing shrub cover to restore habitat spatial structure.