Effects of population size and pollinator limitation on seed‐set ofPrimula sieboldiipopulations in a fragmented landscape

Abstract

Female reproductive success, fruit and seed‐set and factors affecting them were measured for 3 years (1995–1997) for 24 populations of Primula sieboldii E. Morren, a threatened Japanese plant species in a highly fragmented landscape in southern Hokkaido. The smaller populations (genets <=; 3) set almost no seeds consistently during the study years. In larger populations (genets >= 7), proportions of failed flowers without damage from fungi or herbivores were relatively high, but fruit set per flower varied among the populations in 1995. Correlations of fruit (r = 0.589, P = 0.011) and seed‐ set (r = 0.688, P < 0.01) with population pollinator availability were highly significant. In 1995, pollination failure would be the most plausible reason for the variation in reproductive success among the populations. However, pollinator availability was relatively high in all populations in 1996 and 1997. In these years, higher proportions of fruit failed because of antagonistic biological interactions. In the populations with poor pollinator availability in 1995, mean fruit and seed‐sets were greater in the long‐styled morph than in the short‐styled morph. Such between‐morph differences are thought to be caused by partial self‐compatibility of the long‐styled morph and the results of hand pollination experiments support this hypothesis.

Genetic diversity of central and peripheral populations of Toona ciliata var. pubescens, an endangered tree species endemic to China

“…The direct result of this is the loss of pollinators (Matsumura and Washitani, 2000) and the formation of central and peripheral populations (Wang et al, 2002). Central populations are usually large and continuous in their distribution, occupying suitable habitat conditions (Huang et al, 2005), while peripheral populations occupy less suitable habitats and are more sensitive to climate change.…”

Reproduction of Amorpha canescens (Fabaceae) and diversity of its bee community in a fragmented landscape

“…2d). Similarly, positive relationships between plant reproduction and pollinator abundance or diversity have been shown in small experimental plantings (SteVan-Dewenter and Tscharntke 1999), small natural populations of an endangered species (Matsumura and Washitani 2000), and in Indonesian coVee plantations where diversity was considered more important to pollination that abundance (Klein et al 2003). The signiWcant relationships between plant reproduction and bee species diversity may be due to diVerences in ability of species to successfully move pollen (Larsen et al 2005) or because diVerent species occupy unique or nearly unique temporal and spatial visitation niche dimensions.…”

“…Of particular interest are the relationships between plant reproduction and reduced pollinator diversity (Klein et al 2003(Klein et al , 2008, decreased site size (Jennersten 1988;Aizen and Feinsinger 1994;Ågren 1996;Morgan 1999;Brys et al 2004), and altered plant population (Richards et al 1999;Matsumura and Washitani 2000) or habitat patch characteristics (Tscharntke et al 1998;SteVanDewenter and Tscharntke 1999). EVects of fragmentation on pollinator diversity and abundance should in turn be examined by studying relationships to site size and Xoral diversity (Heithaus 1974;Potts et al 2003).…”

Reconstructing the pollinator community and predicting seed set from hydrocarbon footprints on flowers

“…There have been attempts to assess pollinator visitation indirectly by recording the "tripped status" of Xowers (Parker 1997) or pollinator claw marks and subsequent color changes of the visited Xowers due to Xoral tissue damage (Matsumura and Washitani 2000). However, neither of these methods provide information on visitation frequency or the composition of the pollinator community.…”