An experimental study of ecotones: The effect of habitat on the population biology of Carex blanda

Different environmental habitats comprise diverse physical and biotic factors that influence the life cycles, numbers, and spatial distribution of the organisms living therein.  Transitions between habitats (i.e. ecotones) are ubiquitous in natural landscapes and can be studied by a combination of observational and experimental approaches.  Plants are particularly useful target organisms because they often can be cloned and transplanted across diverse habitats.  The sedge, Carex blanda, is an ideal plant for studying the effects of ecotones because it is commonly found in forested areas but we have also observed plants in forest edges and open grasslands in eastern Kansas.  Based on these observations, we established a field transplant experiment across a forest/edge/grassland ecotone to determine the effects of ecotones on the survival, growth, and reproduction of this plant, as well as its interactions with other species, such as pathogens.  In our study, we collected plants from forest habitats, cloned them in the greenhouse, and then transplanted plants into forest, edge, and grassland habitats.  Over a six-month period, individuals survived equally well in all habitats.  Although basal area differences were relatively small among habitats, plants in the grassland were shorter.  A rust fungus, Puccinia caricina, was commonly observed on edge and forest plants, but not grassland plants.  These field studies, combined with planned ecophysiological research, contribute to a greater understanding of the effect of ecotones on plant populations.