2020 ESA Annual Meeting (August 3 - 6)

COS 54 Abstract - Compounding effects of fragmentation in a floating clonal plant

Michael Adomako, Institute of Wetland Ecology and Clone Ecology, School of Life Sciences, Taizhou University, Taizhou, Zhejiang Province, China, Peter Alpert, Biology, University of Massachusetts, Amherst, MA, DaoLin Du, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China and Fei-Hai Yu, College of Nature Conservation, Beijing Forestry University, China; Institute of Wetland and Clone Ecology, School of Life Sciences, Taizhou University, Taizhou, China
Background/Question/Methods

Background Fragmentation of plant clones prevents resource sharing between ramets but can promote production of new ramets. This can result in positive or negative net effects on short-term clonal performance, depending in part on resource availability.

Questions Whether effects (1) compound over multiple vegetative generations when fragmentation is chronic or (2) persist when fragmentation is intermittent, and (3) how compounding and persistence of effects depend upon resource availability will help determine how fragmentation affects the long-term performance of clones. We addressed these three questions in a greenhouse experiment on the widespread, floating, stoloniferous, invasive species Pistia stratiotes. Floating clonal plants can form extensive mats containing many ramets and are particularly subject to fragmentation.

Methods Single, parental ramets were grown for three weeks during which they produced two to three generations of offspring; connections between new ramets were cut or left intact. Individual offspring were then used as parents in a second, three-week iteration that crossed fragmentation with previous fragmentation in the first iteration. A third iteration yielded eight treatment combinations, zero to 3 rounds of fragmentation at different times in the past. Sets of replicates were harvested, dried, and weighed after each iteration. The experiment was run once at a high level and once at a low level of nutrients.

Results/Conclusions

Results In each iteration, fragmentation increased biomass of the parental ramet, decreased the biomass of the offspring, and increased number of offspring. These effects persisted and compounded from one iteration to another, though more recent fragmentation had stronger effects, and were stronger at low than at high nutrients. Fragmentation did not affect net accumulation of mass by groups after one iteration but increased it after two iterations at low nutrients, and after three iterations at both nutrient levels.

Conclusion Results suggest that both the positive and negative effects of fragmentation on clonal performance can compound and persist over time and can be stronger when resource levels are lower. Even when fragmentation has no short-term net effect on clonal performance, it can have a longer term effect. In some cases, fragmentation may increase the total accumulation of mass by a clone.