Clonal Growth Strategies Along Flooding and Grazing Gradients in Atlantic Coastal Meadows

Abstract

International audienceSpecific composition and species clonal traits were characterized along combined flooding and grazing gradients to answer two questions. i) To what extent does the interaction of flooding and grazing influence the clonal characteristics of the vegetation? ii) Are the effects of both environmental factors independent or interactive? This study was carried out in a wet meadow along the Atlantic coast (France). Three plant communities (hygrophilous, mesohygrophilous and mesophilous) were distinguished along a flooding gradient and five levels of grazing pressure were controlled through an experimental design (from no grazing to heavy grazing). We monitored species composition and retrieved, for each species, the type of clonal growth organs (CGOs) and clonal traits from the CLO-PLA3 database. We identified two syndromes of clonal traits: "above-ground splitters" and "below-ground integrators". Clonal traits played a key role in plant assembly in the studied meadows. The interaction of both environmental factors selected for particular syndromes of clonal traits; however, flooding had a stronger filtering effect than grazing. The hygrophilous community was dominated by above-ground splitters, whereas the meso-hygrophilous vegetation was dominated by below-ground integrators. In the mesophilous community, clonal composition was the most diverse and shared clonal traits with the vegetation of both the hygrophilous and meso-hygrophilous communities. Grazing impact on CGOs and clonal traits differed between plant communities, i.e., the effect of grazing was modulated by the flooding regime. This study confirmed that vegetation responses to grazing might depend on the pool of traits, primarily filtered by environmental factors such as flooding

Searching for the Relevance of Clonal and Bud Bank Traits Across Floras and Communities

“…The hypothesis by Jónsdóttir and Watson (1997), i.e., that plants with splitting clones prevail in nutrient-rich conditions whereas integrators in nutrient-poor conditions, was supported by Rusch et al (2011). Using the results from other studies here (Wellstein and Kuss 2011;Klimešová et al 2011;Benot et al 2011) we could slightly expand the hypothesis that not only low versus high nutrients but also dry versus wet conditions lead to the same pattern of persistence of connection between ramets. As another finding, lateral spread of integrators in dry-and nutrient-poor conditions seems to be less extensive than previously expected (see also van Groenendael et al 1996;Halassy et al 2005).…”

“…In another study, Benot et al (2011) supported the idea that a bud bank located belowground is important for grazed meadows (Klimešová and Klimeš 2007) but stressed that its functional role in response to grazing can be different in response to the prevailing abiotic conditions. Martínková et al (2011) found that a bud bank on roots of short-lived monocarps may affect their distribution and habitat preferences (Klimešová and Klimeš 2003) and Montserrat-Martí et al (2011) presented a conceptual model on the relationship between bud protection of chamaephytes and climate, which could be further tested in other regions of the world.…”

“…Whether the reason of these patterns is just random "selection effect" or whether given clonal traits themselves are functionally involved in species sorting remains to be tested. Results, in this sense, might easily differ for different cases (compare also Rusch et al 2011;Benot et al 2011) suggesting, at least, that selection effects and stochastic processes are not negligible.…”

Grazing exclusion unleashes competitive plant responses in Iberian Atlantic mountain grasslands

“…; Benot et al. ), limitation of internode length (Amiaud et al. ) and fragmentation of clone patches (Charpentier et al.…”

Morphology, Architecture and Growth of a Clonal Palm, Acoelorrhaphe wrightii

“…The number of ramets within a genet and overall clone circumference have been used to measure architectural variability (Doust, 1991;Cain & Damman, 1997;Price & Marshall, 1999;Sultan, 2000;Benot et al, 2011). Clone circumference, commonly used in studies of architectural variability, can also be used to analyze population structure, where size is taken as a proxy for time or developmental stage (Condit et al, 1998;Lykke, 1998).…”