Asimina triloba patch density and reproduction in four urban forest fragments
132nd Annual Meeting of the Indiana Academy of Science
Asimina triloba (L.) Dunal (pawpaw) is a common moist hardwood forest tree species found throughout the eastern United States. Clonal reproduction in A. triloba contributes to patchy distribution within forests. However, fruit production is also common with flowers pollinated by carrion beetles and flies. The objectives of this study were to describe the habitat characteristics where patches of A. triloba occurred within four forest fragments and to quantify the reproductive strategies within these patches. Forest fragments were selected in Allen County, Indiana. Forest and environmental characteristics were recorded through overstory surveys and measurements of soil compaction, soil moisture, and canopy cover. Within each A. triloba patch, height and diameter were measured for each individual, as well as flower number and subsequent fruit numbers. Additionally, a subset of A. triloba individuals were selected and sampled for dendrochronological analysis. A separate subset of A. triloba individuals were sampled for genetic analysis via inter-simple sequence repeat polymerase chain reaction (ISSR-PCR) to signify successful sexual reproduction and subsequently genotypic diversity. The overstory surveys and environmental characteristic data aligned with previous studies regarding conditions and forest types in which A. triloba is typically found. Patches ranged in number from 100 to over 700 A. triloba individuals with patches being dominated by smaller individuals across all patches. Age structure data indicated that A. triloba is opportunistic in growth strategy. We found a majority of clonal indistinct genotypes with sparse instances of visibly distinct genotypes. While it is often described as shade intolerant, we observed A. triloba tolerated high shade by persisting in smaller size classes until canopy gaps opened at which time growth greatly increased. A. triloba is well equipped to persist in a fragmented environment by utilizing a growth strategy “waiting” for gap formation and both sexual and asexual reproductive strategies.
Aaron J. Rudolph, Vamsi J. Nalam, and Jordan M. Marshall (2017).
Asimina triloba patch density and reproduction in four urban forest fragments. Presented at 132nd Annual Meeting of the Indiana Academy of Science, Indianapolis, IN.