Plant Parentage, Pollination, and Dispersal: How DNA Microsatellites Have Altered the Landscape

Abstract

DNA microsatellites provide plant ecologists with molecular markers precise enough to assign parentage to seeds and seedlings. This allows the exact distance and trajectory of successful pollen to be traced to characterize pollination patterns. Parentage assignment of established seedlings also allows researchers to accurately determine how far new recruits have traveled from their seed parent. This paper reviews the history and development of molecular parentage assignment in studies of native plants, as well as the limitations and constraints to this approach. This paper also reviews 53 articles published in the past 15 years that use parentage assignment to study pollination and seed dispersal in native plants. These parentage studies have overturned many common assumptions regarding pollen and seed dispersal patterns. They show that long-distance dispersal of pollen is common in both wind and animal dispersed systems, with average pollination distances commonly being hundreds of meters. The pollination neighborhood is often extremely large, and simple dispersal functions based on distance alone fail to make accurate predictions of pollination. Rather than hindering gene flow, fragmentation and isolation sometimes, and perhaps even commonly, results in increased pollination distances. Studies of seed dispersal using parentage assignment have also yielded some surprises. We now know that it may be erroneous to assume that seeds growing under the crown of a conspecific adult are growing beneath their mother, or that seed dispersal distances are more limited than pollen dispersal distances. Taken together, the studies to date demonstrate that both seed and pollen dispersal are quite complex phenomenon influenced by many ecological processes.

Population at the edge: increased divergence but not inbreeding towards northern range limit in Acer campestre

“…within isolated populations. Nonetheless, as mentioned in the introduction, field maple is likely capable of (at least incidental) wind-pollination, which is generally known to facilitate long pollen flow (Ashley 2010 and references therein). Also, insect-pollination can be very effective in terms of dispersal distances, as shown in the case of many fragmented tropical species (Nason and Hamrick 1997;White et al 2002).…”

Inferring contemporary dispersal processes in plant metapopulations: comparison of direct and indirect estimates of dispersal for the annual species Crepis sancta

“…C. sancta produces many seeds with a pappus that provides high potential dispersal ability. Substantial immigration from an unknown source was previously considered as rare but recent studies using parentage analysis have found such seed immigration in trees (Ashley, 2010), with a record of 50-70% in fragmented populations of Fraxinus excelsior (Bacles et al, 2006). Such data remain rare in annual plants but our study documented high seed immigration rates that differed between the two networks.…”

Effects of converting natural forests to coniferous plantations on fruit and seed production and mating patterns in wild cherry trees

“…On the other hand, the most predictable scale for the effect of the natural-forest area on the biparental-inbreeding rate and correlated paternity was the 500-ha buffer area with the 1.26-km radius. Thus, long-distance pollen dispersal occurring such a large scale may affect the overall mating patterns (Kramer et al 2008;Ashley 2010). This spatial scale corresponds to the foraging ranges of some P. verecunda pollinators, such as birds and bees (Beekman and Ratnieks 2000;Lepais et al 2010;Hagen et al 2011;Aslan et al 2014).…”

“…Pollen dispersal distance indicates the spatial scale, at which the properties of landscapes and populations affect the reproductive performance (Sork and Smouse 2006;Ashley 2010). However, we were unable to estimate the pollen dispersal distance in P. verecunda from the correlated paternity between the maternal trees.…”