Chin J Plant Ecol ›› 2012, Vol. 36 ›› Issue (8): 747-753.DOI: 10.3724/SP.J.1258.2012.00747

• Research Articles • Previous Articles     Next Articles

Spatial difference and regularity of seed dispersal of Ulmus macrocarpa in Horqin Sandy Land, China

YANG Yun-Fei*(), BAI Yun-Peng, LI Jian-Dong   

  1. Key Laboratory for Vegetation Ecology of Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun 130024, China
  • Received:2011-11-09 Accepted:2012-04-25 Online:2012-11-09 Published:2012-08-21
  • Contact: YANG Yun-Fei

Abstract:

Aims Ulmus macrocarpa is a typical anemochorous plant. It can form mono-dominant woodland in Keerqin Sandy Land, China. Our objectives were to investigate seed-fall characteristics of U. macrocarpa in the understory and away from both the woodland edges and isolated trees at different distances in different compass directions, and to illustrate the underlying mechanisms of seed dispersal in U. macrocarpa.
Methods
In mid June 2011, we investigated seed dispersal after seeds fall in a nature reserve of U. macrocarpa woodland in Tongyu County in western Jilin Province. The woodland is about 50 km2in area which has nearly primitive landscape appearance. The seed density of U. macrocarpa was randomly sampled in the understory and orderly sampled at 1 m intervals from the tree bases away from the woodland edges and isolated trees along vertical sections of different directions. The quadrat was 50 cm × 50 cm in area. Differences in the seed density among the understory and parallel sections of different distance away from the woodland edges were tested by one-way ANOVA. Two types of density functions of theoretical distribution were used to reflect the patterns of seed dispersal away from seed sources along vertical sections of different directions.
Important findings The understory of U. macrocarpa had the highest mean seed density. The mean seed density was significantly reduced at 3 m away from the woodland edges, and it decreased exponentially with increasing in distance away from the woodland edges. We observed the highest cumulative seeds per unit area in the northeast direction; whereas the lowest numbers in the southwest and west directions, which may attribute to a high frequency of southerly winds. The pattern of seed dispersal matched the Weibull and Log-normal distributions (χ2(α) < 0.900). In conclusion, U. macrocarpa has the same long-distance seed dispersal mechanism in different directions under natural conditions in Horqin Sandy Land.

Key words: anemochorous plant, isolated tree, seed dispersal, Ulmus macrocarpa, understory, woodland edge