Effects of patch size and density on flower visitation and seed set of wild plants: a pan‐European approach

Abstract

Summary 1.Habitat fragmentation can affect pollinator and plant population structure in terms of species composition, abundance, area covered and density of flowering plants. This, in turn, may affect pollinator visitation frequency, pollen deposition, seed set and plant fitness. 2. A reduction in the quantity of flower visits can be coupled with a reduction in the quality of pollination service and hence the plants' overall reproductive success and long-term survival. Understanding the relationship between plant population size and ⁄ or isolation and pollination limitation is of fundamental importance for plant conservation. 3. We examined flower visitation and seed set of 10 different plant species from five European countries to investigate the general effects of plant populations size and density, both within (patch level) and between populations (population level), on seed set and pollination limitation. 4. We found evidence that the effects of area and density of flowering plant assemblages were generally more pronounced at the patch level than at the population level. We also found that patch and population level together influenced flower visitation and seed set, and the latter increased with increasing patch area and density, but this effect was only apparent in small populations. 5. Synthesis. By using an extensive pan-European data set on flower visitation and seed set we have identified a general pattern in the interplay between the attractiveness of flowering plant patches for pollinators and density dependence of flower visitation, and also a strong plant species-specific response to habitat fragmentation effects. This can guide efforts to conserve plant-pollinator interactions, ecosystem functioning and plant fitness in fragmented habitats.

Breeding system variability, pollination biology, and reproductive success of rare Polemonium caeruleum L. in NE Poland

“…As the appropriate pollinators' assemblages are strictly connected with the availability of suitable habitats [14,15], their service for plants resulting in reproductive success is modified by plant population properties. Pollinator visitation rates, time spent on the plant, number of flowers and individuals visited during a single bout may vary depending on the size of the plant population, density, and spatial pattern of flowering shoots [11,[16][17][18].…”

Effects of local conspecific abundance on seed set and seed predation, and control of Carpinus laxiflora (Betulaceae) population density

“…However, local abundance was measured within a radius of 80 m in both studies, and whether the most effective distance is larger remains unknown. Pollen limitation has also been reported for insect-pollinated plants (Silander 1978, House 1993, Ghazoul et al 1998, García and Chacoff 2007, Dauber et al 2010, Jakobsson and Ågren 2014. Among basal areas of target individuals did not have significant effects in most situations (Table 1).…”

“…Target individuals were selected to cover a wide range of local conspecific tree densities, and locations of target individuals and neighboring reproductive individuals were recorded using a Garmin Global Positioning System (GPS) (Oregon 450 model; Garmin, Olathe, KS, USA). The error of Oregon 450 in the forest was within about 5 m. The locations and GBHs of all repro- Dauber et al 2010). Pollen limitations were also reported for wind-pollinated plants (Knapp et al 2001).…”

Effect of rosette size, clonality and spatial distribution on the reproduction of Vriesea carinata (Bromeliaceae) in the Atlantic Forest of Paraná, southern Brazil

“…Bigger plants do not result in higher reproductive eff ort even when biomass was measured with infl orescences. Th e reproductive eff ort in V. carinata diff ers from what has been reported for other species, because fl ower production is frequently correlated with plant size, which usually increases with increased resource availability (Ågren et al 2008;Dauber et al 2010). In bromeliads, sexual reproduction tends to increase with an increase in plant size (Benzing 1981;Hietz et al 2002;Mondragón et al 2004;Mantovani & Iglesias 2009).…”