Canopy disturbance and gap partitioning promote the persistence of a pioneer tree population in a near‐climax temperate forest of the Qinling Mountains, China

Relatively few flowering plants show ambophily (pollination by both wind and insects), and whether and when ambophily is advantageous has not been studied well. In the present study, we report ambophily in two dioecious pioneer tree species, Mallotus japonicus Müll.Arg. in a temperate forest of Japan, and Mallotus wrayi King ex Hook.f. in a tropical forest of Borneo, and discuss the conditions that contribute to the maintenance of ambophily. Both species are pollinated by wind because they set fruits even when flower visitors were excluded and because substantial amounts of airborne pollen reached female trees. Insects may also contribute to fruit set, because insects with body pollen visited female inflorescences. Because M. japonicus and M. wrayi exhibit floral characteristics that are adapted to both wind and insect pollination, ambophily may be actively maintained in the two species at the study sites and perhaps elsewhere. Whereas previous studies have indicated that ambophily is advantageous for pioneer plants because of changing wind conditions during forest succession, our preliminary data suggest that changes in population density also contribute to the maintenance of ambophily in M. japonicus.

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Species Diversity and Small-Scale Disturbance in an Old-Growth Temperate Forest: A Consideration of Gap Partitioning Concepts

Oikos ◽

10.2307/3545618 ◽

1997 ◽

Vol 78 (3) ◽

pp. 562 ◽

Cited By ~ 91

Author(s):

Richard T. Busing ◽

Peter S. White

Keyword(s):

Species Diversity ◽

Temperate Forest ◽

Small Scale ◽

Old Growth ◽

Gap Partitioning

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Importance of nurse logs as a substrate for the regeneration of pioneer tree species on Barro Colorado Island, Panama

Journal of Tropical Ecology ◽

10.1017/s0266467409006130 ◽

2009 ◽

Vol 25 (4) ◽

pp. 429-437 ◽

Cited By ~ 12

Author(s):

Evelyn Sanchez ◽

Rachel Gallery ◽

James W. Dalling

Keyword(s):

Growth Rates ◽

Temperate Forest ◽

Forest Canopy ◽

Barro Colorado Island ◽

Wood Substrate ◽

Seedling Density ◽

Soil Seed Banks ◽

Treefall Gaps ◽

Pioneer Tree ◽

Nurse Logs

Abstract:Fallen tree trunks (‘nurse logs’) are important recruitment sites for trees in temperate forest, however nurse log use is seldom reported in tropical forests. We predicted that logs should be important for the regeneration of small-seeded tropical pioneer species because surface leaf litter and competition with established vegetation reduces the establishment success of these species from soil seed banks. In a survey on Barro Colorado Island, Panama, we found that pioneer seedlings were present on logs in 40 of 95 recent treefall gaps. In gaps where seedlings were present on logs, seedling density was not significantly different from adjacent areas of soil. However, species composition was significantly different; logs were disproportionately colonized by smaller-seeded and wind-dispersed species. In growing-house experiments using 12 species, we found that wood substrate had little effect on seed germination. In contrast, seedling growth was 50% lower on decayed wood than soil. Furthermore, species growth rates on wood were not significantly correlated with growth rates in soil (df = 10, r = 0.48). If establishment on logs eventually leads to recruitment to the forest canopy, then logs may promote the maintenance of diversity by favouring a different group of species from those that recruit in soil.

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Histoire holocène du climat et de la végétation à Lanoraie (Québec)

Canadian Journal of Earth Sciences ◽

10.1139/e82-172 ◽

1982 ◽

Vol 19 (10) ◽

pp. 1938-1952 ◽

Cited By ~ 17

Author(s):

Paul Comtois

Keyword(s):

Temperate Forest ◽

Sugar Maple ◽

Vegetation History ◽

Isotopic Ratio ◽

Isotopic Ratios ◽

Climatic Variations ◽

Pioneer Tree ◽

History Of ◽

Oxygen Isotopic ◽

Climatic Cooling

Four different cores were recovered from the same peat complex at Lanoraie (Québec), and have been used to evaluate, by pollen analysis, possible differences in the representation of the vegetation history. The isotopic ratio of oxygen has been used to indicate climatic variations involved in these processes.This method was first tested and calibrated with modern moss samples. A transect of 15 samples, from the temperate forest to the tundra, indicates that annual mean temperatures and evapotranspiration rates have a predominant influence on oxygen isotopic ratios. A sequence of fossil sediments, interpreted in terms of these results, shows a climatic maximum at 3500 BP and a reduction of temperature since 1500 BP in the Lanoraie region.The history of the regional vegetation shows the following succession of stages: (1) establishment of pioneer tree vegetation of pine, oak, elm, and walnut; (2) buildup of a sugar maple forest, contemporaneous with the migration of beech and correlated with a maximum pollen influx and a climatic optimum at about 3500 BP; (3) increase of the representation of spruce and fir after 1500 BP, related to a climatic cooling. Paleobotanical data–the recurrence of ruderal spectra and the presence of Iva xanthifolia– suggest the occurrence of two prehistoric anthropic periods, one before 3500 BP and the other at ca. 1500 BP.

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