The choice of seed tracking method influenced fate of beech seeds dispersed by rodents

Abstract

We tracked seeds of European beech (Fagus sylvatica) dispersed by rodents in Gorzowska Forest (western Poland). We used two seed labeling methods, marking with UV-fluorescent powder and with plastic tags, to test whether using different marking methods influences results of seed tracking. The removal rates did not differ among seeds marked with UV-powder, seeds labeled with tags, and unmanipulated seeds. We found 78 % of removed seeds marked with tags, but only 25 % of UV-marked seeds. The consumption rates of tagged and UV-marked seeds were dramatically different: rodents ate 83 % of the former and 26 % of the later. The average dispersal distance was larger for seeds marked with UV-powder than for tagged seeds. Our findings suggest that the choice of seed tracking method might influence results of seed dispersal studies.

Advantages of masting in European beech: timing of granivore satiation and benefits of seed caching support the predator dispersal hypothesis

“…If rodents avoided experimental seeds in mast years (when food was abundant), but not in nonmast years (when food was scarce), then our experiments would underestimate the magnitude of seed removal in mast years. We note, however, that seed removal is typically unaffected by seed marking (Sork 1984;Li and Zhang 2003;Hirsch et al 2012;Wróbel and Zwolak 2013), and we left our experimental cages in the field for over 6 months, allowing mice to familiarize themselves with these structures.…”

“…In a study conducted in a beech forest, seeds comprised 74 % of stomach volume in yellow-necked mice (averages from one mast and one nonmast year : Dróżdż 1966). This rodent species also larderhoards and scatterhoards seeds (Jensen 1985;Wróbel and Zwolak 2013). Beech masting causes strong fluctuations in populations of granivorous rodents, with peaks (1 year after masting) followed by crashes (2 years after masting : Jensen 1982).…”

“…A 0.8-mmdiameter hole was drilled through cotyledons and a stainless steel wire (100 mm in length, 0.2 mm in diameter) with a red, uniquely numbered plastic tag (20 × 40 mm) was secured through the hole. The wire and the tag weighed 0.141 ± 0.004 g. Although seed tagging (and most other methods used to mark seeds for subsequent tracking) may influence rodent behavior, our objective was to compare the fates of identically manipulated seeds in mast and nonmast years (Wróbel and Zwolak 2013).…”

Tricky to track: comparing different tagging methods for tracing beechnut dispersal by small mammals

“…For tying up wires or threads to seeds or for inserting magnets, small holes were drilled through the exocarp in many cases (e.g., Seiwa et al 2002;Xiao et al 2006;Yi et al 2008 Wro´bel and Zwolak (2013) used this method to tie tags to beechnuts. To avoid possibly negative effects of drilling on seed fates, we fixed wire (inclusive flat washers) and transmitters with solvent-free glue to the seeds, or used wire loop bonding.…”

When losing your nuts increases your reproductive success: sandalwood (Santalum spicatum) nut caching by the woylie (Bettongia penicillata)

“…Tracking the fate of seeds depredated by mammals has relied on a range of techniques including: spool and thread (Forget 1993;Dennis 2003), fluorescent dyes (Longland and Clements 1995;Wróbel and Zwolak 2013), transponder tags (Suselbeek et al 2013) and transponders with flagging tape for burrowing bettongs (Chapman 2015). In addition, 46 Scandium ( 46 Sc) has been used successfully for tracking seeds in the USA (Abbott and Quink 1970;Waitman et al 2012).…”