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

• Published in: Ecosphere (Washington, D.C) Vol. 3; no. 7; pp. art68 - 12
• Main Authors: Takahashi, Mizuki K, Kubota, Toshiro, Horner, Liana M, Keller, Nathan A, Abrahamson, Warren G
• Format: Journal Article
• Language: English
• Published: Washington Ecological Society of America 01-07-2012; John Wiley & Sons, Inc
• Subjects: AFLP; clonal plants; Cloning; Competition; Deoxyribonucleic acid; Distribution patterns; DNA; DNA fingerprints; Fruits; Plant populations; Sabal etonia; Seedlings; Serenoa repens; Signatures; Spatial analysis; Spatial distribution; Studies
• ISSN: 2150-8925; 2150-8925
• DOI: 10.1890/ES12-00101.1

Spatial analyses of plant-distribution patterns can provide inferences about intra- and interspecific biotic interactions. Yet, such analyses are rare for clonal plants because effective tools (i.e., molecular markers) needed to map naturally occurring clonal individuals have only become available recently. Clonal plants are unique in that a single genotype has a potential to spatially place new individuals (i.e., ramets) in response to intra- and interspecific biotic interactions. Laboratory and greenhouse studies suggest that some clonal plants can avoid intra-genet, inter-genet, and inter-specific competition via root-placement patterns. An intriguing and yet to be explored question is whether a spatial signature of such multi-level biotic interactions can be detected in natural plant communities. The facultatively clonal
Serenoa repens
and non-clonal
Sabal etonia
are ecologically similar and co-dominant palmettos that sympatrically occur in the Florida peninsula. We used amplified fragment length polymorphisms (AFLPs) to identify
Serenoa
genets and also to assign field-unidentifiable small individuals as
Sabal
seedlings,
Serenoa
seedlings, or
Serenoa
vegetative sprouts. Then, we conducted univariate and bivariate multi-distance spatial analyses to examine the spatial interactions of
Serenoa
(
n
= 271) and
Sabal
(
n
= 137) within a 20 × 20 m grid at three levels, intragenet, intergenet and interspecific. We found that spatial interactions were not random at all three levels of biotic interactions.
Serenoa
genets appear to spatially avoid self-competition as well as inter-genet competition. Furthermore,
Serenoa
and
Sabal
were spatially negatively associated with each other. However, this negative association pattern was also evident in a spatial comparison between non-clonal
Serenoa
and
Sabal
, suggesting that
Serenoa
genets' spatial avoidance of
Sabal
through placement of new ramets is not the explanation of the interspecific-level negative spatial pattern. Our results emphasize the importance of investigating spatial signatures of biotic as well as abiotic interactions at multiple levels in understanding spatial distribution patterns of clonal plants in natural plant communities.