Biotic and abiotic drivers of dipterocarp seedling survival following mast fruiting in Malaysian Borneo

Abstract

Abstract:South-East Asian tropical rain forests experience sporadic, but profuse, seed production after general flowering, leading to the synchronous emergence of various seedlings and subsequent seedling dynamics, which play a crucial role in determining species distribution and coexistence. We examined the relative importance of both biotic (initial height, conspecific seedling density) and abiotic (canopy openness, per cent sand, soil water content) drivers using survival data for 1842 seedlings of 12 dipterocarp species for 1.5 y following mast fruiting in an old-growth Bornean tropical rain forest. More than 30% of all dipterocarp seedlings survived 1.5 y after mast fruiting. When all species were analysed together, we found that initial seedling height, canopy openness and conspecific seedling density affected dipterocarp seedling survival. Negative density dependence indicated that predators were not satiated, but dipterocarp seedlings rather suffered from host-specific natural enemies or intraspecific competition. Species-level analyses of seven dipterocarp species showed large variation in response to biotic and abiotic factors. These results suggest that interspecific differences in the relative importance of biotic and abiotic effects on seedling survival might contribute to species coexistence.

Early emergence increases survival of tree seedlings in Central European temperate forests despite severe late frost

“…The observed decline in mortality risk with increasing seedling height agrees with observations that initial height is positively correlated with survival probability (Fidej, Rozman, & Diaci, ; Oshima, Tokumoto, & Nakagawa, ). We used seedling height as a time‐varying variable instead of initial height, because of the uncertainty related to double censored emergence times.…”

Effects of biotic neighbors and habitat heterogeneity on tree seedling survival in a secondary mixed conifer and broad-leaved forest in Changbai Mountain

“…为脆弱、对生境变化最为敏感的时期 (Clark & Clark, 1984;Wright et al, 2005;Muller-Landau et al, 2008), 植物体在幼苗阶段具有较明显的时空变化 (李晓亮等, 2009; 张健等, 2009)。 因此探究导致群落 乔木幼苗动态变化的原因对于理解群落物种共存具 有重要意义 (Kelly & Bowler, 2002;Queenborough et al, 2007), 有助于我们了解和预测群落的组成、演 替过程, 以及进行合理的森林经营 (Wright et al, 2005;Muller-Landau et al, 2008)。 林下幼苗的更新过程是森林生态学研究的重要 内容, 近年来国内外学者做了大量研究, 其主要内 容包括: 1)幼苗的时空格局与动态 (Wright et al, 2005), 如Metz等(2008)分析了4块热带样地的幼苗 数据, 表明幼苗数量存在较大的时间和空间变异, 这些变异主要是由幼苗个体的新生和死亡所导致 的; 2)负密度制约理论和生态位理论等物种共存机 制假说的验证 (Canham et al, 2004;Muller-Landau et al, 2008;Comita & Engelbrecht, 2009;Queenborough et al, 2009;Metz et al, 2010;Metz, 2012;Oshima et al, 2015), 如Comita和Hubbell ( (Chen et al, 2010;Bai et al, 2012;Lin et al, 2014;肖翠等, 2015) ratios > 1 (95%的置信区间)表明是正相关; 而Odds. 图4 不同种子传播模式乔木幼苗存活最优模型各参数的优势比率, 圆圈表示各参数在模型中的估计值, 水平线表示95%的 置信区间, 显著的参数估计值用实心圆表示, 参数缩写见表2。 Fig.…”

“…ratios significantly different from 1 (95% CL do not overlap 1) are indicated by filled circles. See Table 2 (Chen et al, 2010;Bai et al, 2012;Oshima et al, 2015) Kraft et al, 2011), 但是我们的研究结果发现负密 度制约效应也存在于幼苗邻体之间 (Webb et al, 2006;Queenborough et al, 2007;Comita & Engelbrecht, 2009;Chen et al, 2010;Bai et al, 2012;Lin et al, 2014 …”

Understanding tropical biodiversity to improve reforestation outcomes: examples from the Philippines and Northern Australia

“…The Dipterocarpaceae family is abiotically dispersed and ecologically dominant, particularly within Asia (Oshima et al, 2015). This family is also economically important, as it accounted for a quarter of the global consumption of tropical hardwood between (Kettle, 2010.…”

“…Dipterocarps are known for their irregular mast fruiting events; therefore, low populations of mature trees and irregular fruiting are likely impediments restricting colonization irrespective of seed size (Oshima et al, 2015). The high value of these species has led to high rates of logging and resulted in a low number of mother trees.…”