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Effects of disperser abundance, seed type, and interspecific seed availability on dispersal distance

100%

Liu C., Liu G., Shen Z., Yi X.

Acta Theriologica

2013

tom 58

nr 3

Seed dispersal distance is influenced by a variety of seed properties and functional responses of dispersers. However, to our knowledge, how and why seed dispersal distances are determined remains poorly understood. In the present study, seeds of sympatric tree species, Pinus koraiensis, Corylus mandshurica, Corylus heterophylla, and Quercus mongolica were released to investigate the effects of rodent abundance, seed type, and seed availability on seed dispersal. Our results showed that seeds of P. koraiensis were dispersed further than those of C. heterophylla and C. mandshurica regardless of the ambient rodent and seed abundances, reflecting a consistent effect of seed type on seed dispersal distances. Seed dispersal distance was greatly facilitated by lower per-capita seed abundance (the ratio of seeds to rodents); however, seed caching and cache survival were benefited from higher per-capita seed abundance. Although seed dispersal and seed caching of a particular tree species can be enhanced by its own seed availability, no consistent influence was detected at interspecific levels, reflecting different interspecific effects of seed availability on seed dispersal of sympatric seed species. Our results provide evidences that the effect of seed availability on seed dispersal should be evaluated in terms of per-capita seed abundance and interspecific effects, rather than the independent influence of seed or disperser abundances.

Dispersal distance and burial mode of acorns in Eurasian Jays Garrulus glandarius in European temperate forests

84%

Kurek P., Dobrowolska D., Wiatrowska B.

Acta Ornithologica

2018

tom 53

nr 2

Dispersal distance and burial mode of acorns are two of the most important characteristics in renewal processes of oaks that result from the food hoarding ecology of the Eurasian Jay Garrulus glandarius. To obtain the dispersal distance and to locate precisely the caches with scattered acorns we used radio-tracked transmitters with flexible 13 cm long sticking out antennae injected into drilled acorns. From mid-September to mid-October acorns of Pedunculate Oak Quercus robur with transmitters were mixed with untagged acorns and exhibited on five feeders distributed from each other at a distance of at least 1.3 km (max. 3.8). We obtained information on 121 tagged acorns scattered by Jays in two consecutive years (2014 - 42 records, 2015 - 79 records). For both seasons, mean dispersal distance was 115.7 metres (SE = 9.2). The maximum detected distance was 456 m, the minimum was 3 m. Most of the acorns (52.6%) were deposited by Jays up to 100 m from the source. Dispersal distance differed significantly between the two years of research and between feeders. Mean dispersal distance was much higher in 2014 (166 m, N = 42) than in 2015 (86 m, N = 72) and differed between seasons while the seed crop was similar and low. Only four acorns (3.5%) were found on the litter with no signs of hiding, which suggests accidental loss during transport (dyszoochory). Most of the cached acorns (44.6%) were deposited in the Scots Pine Pinus silvestris litter or moss cushions no deeper than 0.5 cm. The additional covering of caches with pieces of bark or leaves were noted accidentally in nine cases (9.8%).

Ograniczanie wyników

1 Acta Ornithologica

1 Acta Theriologica

1 Dobrowolska D.

1 Kurek P.

1 Liu C.

1 Liu G.

1 Shen Z.

1 Wiatrowska B.

1 Yi X.

1 2018

1 2013

Wyniki wyszukiwania

Effects of disperser abundance, seed type, and interspecific seed availability on dispersal distance

Dispersal distance and burial mode of acorns in Eurasian Jays Garrulus glandarius in European temperate forests