Long‐term changes in liana loads and tree dynamics in a Malaysian forest

Abstract

Abstract. The importance of lianas through time and their effect on tree reproduction are evaluated for the first time in a Southeast Asian Dipterocarp forest. We quantified flower and seed production by lianas and trees for 13 years, assessed liana loads in the crowns of all trees larger than 30 cm in diameter at breast height (1.3 m) in 2002 and 2014, and assessed levels of reproduction for the same trees during a strong general flowering event in 2014 for the 50-ha forest dynamics plot at the Pasoh Forest Reserve, Malaysia. General flowering refers to synchronous reproduction by hundreds of plant species at irregular, multiyear intervals and only occurs in Southeast Asian Dipterocarp forests. Overall, lianas were present in 50% of tree crowns and comprised 31% of flower production and 46% of seed production. Lianas reduced growth, survival, and reproduction by their host trees. Lianas were less frequent in canopyemergent trees, Dipterocarps comprised a disproportionately large proportion of canopy emergents, and, as a consequence, lianas were less frequent in Dipterocarps than in trees from other plant families. Lianas infested the crowns of significantly fewer trees in 2014 (47.9%) than in 2002 (52.3%); however, the decrease was restricted to trees with the lightest liana loads and sample sizes and statistical power were enormous. Lianas comprised a stable proportion of flower production and a highly variable proportion of seed production from 2002 through 2013. We conclude lianas have a huge impact on trees in this forest and were a stable component of the forest between 2002 and 2014. The emergent habit and associated ability to avoid lianas might contribute to the success of the Dipterocarpaceae.

No strong evidence for increasing liana abundance in the Myristicaceae of a Neotropical aseasonal rain forest

“…Liana density is highest in tropical South America, followed by Africa, Central America, and Asia (462, 374, 351 and 223 individuals/ha, respectively), whereas diversity is highest in Africa followed by South America, Central America, and lastly Asia (Fisher's α of 26.0, 15.5, 12.1 and 6.6, respectively; DeWalt et al 2015). The trees of this family are typical emergent with few low branches, and lianas have a lower probability of occurrence in their crowns (Wright et al 2015). Lianas outcompeting trees might therefore be a regular and repeatable observation in Neotropical forests, through a product of the interaction between tree and liana community composition and structure that is absent from other tropical regions.…”

“…Caballe and Martin (2001) observed a 20% decrease in liana density, compared to 5% decrease in tree density in a Gabonese semideciduous forest. A single study has analysed long-term liana dynamics in Southeast Asia, again reporting a decrease in the proportion of large trees colonized by lianas over a 10-yr period from an aseasonal tropical forest in Peninsula Malaysia (Wright et al 2015). Thomas et al (2015) observed a 16% decrease in liana density over a 10-yr period in Korup National Park, Cameroon; a forest experiencing a 3-month dry season with mean monthly precipitation <100 mm.…”

Long‐term increases in tropical flowering activity across growth forms in response to rising CO2 and climate change

“…In contrast, smaller understory growth forms tend to have shallower root systems and to be more susceptible to changes in water availability (Becker & Castillo, 1990;Opler, Frankie, & Baker, 1980;Wright, 1991). As another example, woody vines or lianas are a characteristic feature of tropical forests (Gentry, 1991) and are increasing in importance in many Neotropical forests (reviewed by Schnitzer & Bongers, 2011;Wright, Sun, Pickering, Fletcher, & Chen, 2015). As another example, woody vines or lianas are a characteristic feature of tropical forests (Gentry, 1991) and are increasing in importance in many Neotropical forests (reviewed by Schnitzer & Bongers, 2011;Wright, Sun, Pickering, Fletcher, & Chen, 2015).…”

Positive effects of liana cutting on seedlings are reduced during El Niño‐induced drought

“…This increase in liana abundance may enhance the negative impacts on tree demographic rates (i.e. reproduction, regeneration, growth and survival) in aseasonal and seasonal tropical forests alike (Magrach et al., ; Wright, Sun, Pickering, Fletcher, & Chen, ). Although the effect of lianas on forest dynamics has been studied in more seasonal tropical forests (Estrada‐Villegas & Schnitzer, ; Van der Heijden, Powers, & Schnitzer, ), empirical support for the effect of lianas on tree growth and survival remains limited in aseasonal forests of Southeast Asia, which are important biodiversity hotspots of both flora and fauna (Estrada‐Villegas & Schnitzer, ; Myers, Fonseca, Mittermeier, Fonseca, & Kent, ; Wright, Sun, et al., ).…”