Reproductive success and distance to conspecific adults in the sparsely distributed tree Kalopanax pictus

Naomi Fujimori, Hiromitsu Samejima, Tanaka Kenta, Tomoaki Ichie, Mitsue Shibata, Shigeo Iida, Tohru Nakashizuka

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    12 Citations (Scopus)


    To understand how a sparsely distributed species can maintain viable populations, and with a particular interest in distance-dependent reproductive success, we investigated the ovule survival and the factors that determine the survival for sparsely distributed Kalopanax pictus (Araliaceae) in a temperate forest landscape around the Ogawa Forest Reserve, central Japan. We found 154 potentially mature trees (>20 cm diameter at breast height) in a 600-ha site. The year 2000 was a mass flowering year for K. pictus; 96.8% of the trees examined flowered in that year; however, this was less than half of the trees that flowered in other years. The flowers of K. pictus include protandrous inflorescences, which bloom on individual tress in midsummer when few other tree species bloom. We conducted pollination experiments with out-crossed, self-pollinated, bagged, and control inflorescences. Results suggest that self-pollination is limited, partially by low self-compatibility and partially by protandry. Ovule survival from the flower to the seed stages was not dependent on the temporal flowering density of conspecific adults. The flowering habit and presence of effective pollinators may allow K. pictus to avoid the negative effects of sparse distribution on pollination efficiency. However, ovule survival during the ovary development stage depended on infection by a species-specific fungus, Mycosphaerella acanthopanacis. The fungus damages leaves, and the infection intensity depends on the distance between conspecific K. pictus adults. Thus, an advantage of sparse distribution in K. pictus is disease avoidance, whereas its disadvantages are overcome by pollination efficiency.

    Original languageEnglish
    Pages (from-to)195-203
    Number of pages9
    JournalJournal of Plant Research
    Issue number3
    Publication statusPublished - 2006 May


    • Distance-dependent species-specific disease
    • Long-distance pollen exchange
    • Ovule survival
    • Population maintenance
    • Reproduction

    ASJC Scopus subject areas

    • Plant Science


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