Hydrochory Ranking Index
HYDROCHORY RANKING INDEX allows an assessment how well a certain species is adapted to hydrochory (water dispersal) in comparison to other species and dispersal modes.
HYDROCHORY RANKING INDEX is an index that ranges from 0 to 1, with 0 addressing species with the lowest and 1 addressing species with the highest potential for hydrochory. We use the proportion of floating diaspores measured in a standardized lab experiment (Römermann et al., 2005 and unpublished data) as an indicator of hydrochory potential.
Specifically, HYDROCHORY RANKING INDEX is calculated as the percentile rank of the proportion of the respective species still floating after 1 week in relation to all species for which data were available. A value of e.g. 0.55 means that 45 % of the species possess a higher (or identical) hydrochory potential and a higher (or identical) proportion of diaspores still floating after 1 week, respectively.
Actually, the values range from 0.00 and 0.89 as 11 % of the species show a proportion of 100 % floating diaspores after 1 week.
HYDROCHORY RANKING INDEX is calculated from data of floating potential from the LEDA database (Kleyer et al. 2008) as well as from unpublished data.
Hintze, C., Heydel, F., Hoppe, C., Cunze, S., König, A. & Tackenberg, O. (2013). D³: The Dispersal and Diaspore Database - Baseline data and statistics on seed dispersal. Perspect. Plant Ecol. Evol. Syst. 15, 180-192.
Kleyer, M., Bekker, R., Bakker, J., Knevel, I., Thompson, K., Sonnenschein, M., Poschlod, P., van Groenendael, J., Klimes, L., Klimesova, J., Klotz, S., Rusch, G., Hermy, M., Adriaens, D., Boedeltje, G., Bossuyt, B., Endels, P., Götzenberger, L., Hodgson, J., Jackel, A., Dannemann, A., Kühn, I., Kunzmann, D., Ozinga, W., Römermann, C., Stadler, M., Schlegelmilch, J., Steendam, H., Tackenberg, O., Wilmann, B., Cornelissen, J., Eriksson, O., Garnier, E., Fitter, A. und Peco, B. (2008): The LEDA Traitbase: A database of plant life-history traits of North West Europe. - Journal of Ecology 96:1266-1274.
Römermann, C., Tackenberg, O. & Poschlod, P. (2005): Buoyancy. In: Knevel, I.C., Bekker, R.M., Kunzmann, D., Stadler, M., Thompson, K. (eds.): The LEDA traitbase - Collecting and measuring standards of life-history traits of the Northwest European Flora. 101-104. LEDA Traitbase Project, University of Groningen.