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Keywords:

  • Fushan Forest Dynamics Plot;
  • photoperiod;
  • phylogenetic signal;
  • reproductive ecology;
  • resource availability;
  • seasonality

Abstract

Reproductive patterns of tropical and temperate plants are usually associated with climatic seasonality, such as rainfall or temperature, and with their phylogeny. It is still unclear, however, whether plant reproductive phenology is influenced by climatic factors and/or phylogeny in aseasonal subtropical regions. The plant reproductive phenology of a subtropical rain forest in northern Taiwan (24°45′ N, 121°35′ E) was monitored at weekly intervals during a 7-yr period (2002–2009). The flowering patterns of 46 taxa and fruiting patterns of 26 taxa were examined and evaluated in relation to climatic seasonality, phylogenetic constraints, and different phenophases. Our results indicated that most of the studied species reproduced annually. Additionally, both community-wide flowering and fruiting patterns exhibited distinct annual rhythms and varied little among years. The community flowering peak matched seasonal changes in day length, temperature, and irradiance; while the community fruiting peak coincided with an increase in bird richness and the diet-switching of resident omnivorous birds. In addition, phylogenetically closely related species tended to reproduce during the same periods of a year. Neither the mean flowering dates nor seasonal variation in solar radiation, however, was related to the fruit development times. Our results indicate the importance of abiotic, biotic, and evolutionary factors in determining the reproductive phenology in this subtropical forest.

Chinese Abstract

不論是熱帶或是溫帶的植物,其繁殖物候的表現經常與氣候的季節性(如降雨或是溫度)、或是與植物過去的演化歷史有關。然而,在季節性相對不明顯的亞熱帶地區,我們目前仍不清楚植物的繁殖物候表現主要受哪些因子影響。本研究於台灣北部福山亞熱帶雨林,長期監測植物繁殖物候的表現 (2002–2009年),我們檢視46種植物的開花物候與26種植物的結實物候,想要了解在亞熱帶雨林中,植物繁殖物候的表現與當地氣候之季節性、植物演化歷史、不同物候相之間的關係。在福山地區,大多數植物每年都會開花結果,整個植物群落的開花、結果高峰同樣也呈現一個以一年為週期的律動,且幾乎沒有年間變異。福山森林的開花高峰與日照週期、溫度與日照量的季節變化有相關,而結果高峰則可能與冬季鳥類種類增加、當地優勢的雜食性鳥類的食性轉換有關。此外,在譜系上親緣較近的植物其開花、結果的季節也較為相似。植物果實發育時間的長短則與該植物何時開花、或與果實發育過程的日照量高低都沒有關聯。本研究指出氣候因子、生物因子和植物演化的歷史均會影響植物開花結果的物候表現,忽略其中任一項因子皆有可能會導致偏差的結論。