Investigating establishment and dispersal limitations of vernal herbs in secondary forests: a transplant study

Background/Question/Methods

The forest understory provides us with medicinal resources, provides habitat and food to a broader diversity of life, recycles forest nutrients, and creates microclimates. The tree composition in some secondary forests may recover within a century of severe disturbance, yet the understory layers of disturbed forests frequently do not. The goal of this project is to determine which environmental or species dispersal characteristics may have more of an impact on the re-establishment of herbaceous perennials. This is an on-going study of five spring flowering herbaceous species with different primary dispersal mechanisms and underground storage and nutrient retrieval systems. We collected reproducing individuals and transplanted 180 individuals of each species across four different sites in Kentucky. We gathered pre- and post-transplant data that included the plant’s relative size, the presence and successful release of seeds, and the persistence of above-ground vegetation. At the end of the flowering season, we collected and planted seeds of some of these species across the four sites as well as in pots for greenhouse experimentation. We investigated basic environmental characteristics of the four experimental sites as well as all collection sites.

Results/Conclusions

Experimental sites differed in site history, soil composition, and pre-experimental herbaceous composition. Data from the 2009 field season suggest that more than 90% of individuals survived the transplant, and that more than 90% of all flowering individuals from 4 of the 5 species produced seed. Should these trends continue and some of the seeds germinate, then dispersal characteristics may be the main contributing factor to herbaceous re-colonization in these forests.