Extensive clonal spread and extreme longevity in saw palmetto, a foundation clonal plant

Abstract

The lack of effective tools has hampered out ability to assess the size, growth and ages of clonal plants. With Serenoa repens (saw palmetto) as a model, we introduce a novel analytical framework that integrates DNA fingerprinting and mathematical modelling to simulate growth and estimate ages of clonal plants. We also demonstrate the application of such life-history information of clonal plants to provide insight into management plans. Serenoa is an ecologically important foundation species in many Southeastern United States ecosystems; yet, many land managers consider Serenoa a troublesome invasive plant. Accordingly, management plans have been developed to reduce or eliminate Serenoa with little understanding of its life history. Using Amplified Fragment Length Polymorphisms, we genotyped 263 Serenoa and 134 Sabal etonia (a sympatric non-clonal palmetto) samples collected from a 20 × 20 m study plot in Florida scrub. Sabal samples were used to assign small field-unidentifiable palmettos to Serenoa or Sabal and also as a negative control for clone detection. We then mathematically modelled clonal networks to estimate genet ages. Our results suggest that Serenoa predominantly propagate via vegetative sprouts and 10,000-year-old genets may be common, while showing no evidence of clone formation by Sabal. The results of this and our previous studies suggest that: (i) Serenoa has been part of scrub associations for thousands of years, (ii) Serenoa invasion are unlikely and (ii) once Serenoa is eliminated from local communities, its restoration will be difficult. Reevaluation of the current management tools and plans is an urgent task.

The spatial signature of biotic interactions of a clonal and a non‐clonal palmetto in a subtropical plant community

“…First, there were no noticeable gradients in environmental factors such as shading pattern, elevation, and soil type within our small study grid (i.e., 20 3 20 m). Second, Serenoa genets are extremely long-lived (i.e., possibly more than 10,000 yr old; Takahashi et al 2011). It is very likely that the patterns of any environmental gradients in our study grid have changed over such long duration of time; and thus, interference based on the associations between current environmental gradients and spatial patterns of Serenoa and Sabal may be misleading.…”

“…We then analyzed the obtained AFLP binary matrix with STRUCTURE (Pritchard et al 2000) to assign the field-unidentifiable small individuals as Serenoa or Sabal. Details of the procedures used are available in Takahashi et al (2011).…”

“…Rhizomes of sister Serenoa ramets can remain connected for v www.esajournals.org many decades but eventually their connection decays leaving no sign of physical connection, which precludes the detection of true clonalpropagation patterns via observation of clonal connections. By using DNA fingerprinting, our recent study found that 83% of Serenoa's recruitment was via vegetative means at our study site, indicating that Serenoa is highly clonal (Takahashi et al 2011).…”

Dominant species responses to drought in seasonal wetlands: evidence from reciprocal transplants across a moisture gradient1

“…Unfortunately, it is not possible to assess Van De Kerckhove's methodology because details of her methods were not provided. Amplified fragment length polymorphisms methodology has several well-known potential error sources including (a) contaminant fungal or bacterial DNA included with a sample, (b) somatic mutations among ramets of the same genet, and (c) AFLP errors (e.g., Takahashi et al 2011Takahashi et al , 2012. Any one of these errors, unless accounted for in the data analysis, can make samples appear genetically unique when they are not.…”

“…These factors facilitated associations largely composed of sclerophyllous, evergreen species. The vegetation of the study area is appropriately considered as ''old growth'' because it has experienced little anthropogenic disturbance and has persisted for an estimated 50,000 years (Watts and Hansen 1994, Takahashi et al 2011.…”