Abundance of liana species in an Amazonian forest of Brazil reflects neither adventitious root nor foliar sprout production

Abstract

Abstract:Liana abundance and size have increased in neotropical forests. High vegetative reproductive capacity (clonality) may be the cause of high abundance in some liana species. Correlations between vegetative propagation capacity and (1) relative abundance of liana species, (2) rooting and foliar sprouting potentials of congeneric species, and (3) phylogenetic position were determined. Species selection was based on the relative abundance of lianas in ten 0.5-ha parcels in continuous forest within the Biological Dynamics of Forest Fragments Project (BDFFP), Brazil. Five individuals per species were replicated with seven cuttings per individual. Cuttings placed in moistened sand and coconut fibre were observed for 5 mo in a humid greenhouse. Survival percentage, rooting percentage, potential regeneration index and longest root length were determined per species. The two most abundant species (9.3% and 4.1% relative abundance) had low vegetative regeneration capacity, contrary to expectations. However, a significant, positive relationship between vegetative propagation and relative abundance of liana species whose relative abundances were <4% was found. Congeneric species showed no difference in vegetative propagation between rare and abundant species, except congeners of Machaerium. Vegetative reproductive capacity occurred in all major evolutionary lineages, but was highest in Fabaceae and Bignoniaceae, families of high abundance both locally and broadly across Neotropical forests.

Conceptualising the Global Forest Response to Liana Proliferation

“…However, liana removal may have undesirable side effects by removal of the positive liana contributions to ecosystem function (previous section; Box 1). Accordingly, variation in liana ecology, abundance and function within the forest ecosystem requires consideration during management (Piovesan et al, 2018). Therefore, besides removal of exotics, liana cutting is only appropriate for excessively abundant, parasitoid species in heavily disturbed areas, where they are most likely to arrest succession (Schnitzer and Carson, 2001;César et al, 2016).…”

“…In addition to controlling for environmental bias, sampling and analyses can also be implemented to control for liana dominance, through controlled liana cutting to ensure sufficient variation in liana abundance (see Positive Feedbacks, above). However, where there are multiple drivers, large-scale experiments will be crucial for understanding and projecting forest ecosystem responses to change (Fayle et al, 2015), including thresholds and hysteresis (Scheffer and Carpenter, 2003;Carpenter and Brock, 2006;Ratajczak et al, 2018) and liana proliferation (Piovesan et al, 2018).…”

Higher rates of liana regeneration after canopy fall drives species abundance patterns in central Amazonia

“…However, few studies have investigated the direct relationship between resprouting ability and plant density across species in tropical rainforests, especially for liana species (e.g. Nabe-Nielsen & Hall, 2002;Piovesan, Camargo, Burnham, & Ferraz, 2018).…”

“…However, there is still no consensus on whether lianas are increasing globally in tropical forests (Bongers & Ewango, 2015; see Gerolamo, Nogueira, Costa, Castilho, & Angyalossy, 2018), and the mechanisms behind the abundance changes are also unclear. The capacity to resprout after mechanical damage has been suggested to be positively correlated with local and regional abundances of lianas in many forests (Burnham, 2004;Ledo & Schnitzer, 2014;Nabe-Nielsen, 2004;Piovesan et al, 2018). In these cases, different local abundances and increases in density following canopy disturbances may be explained by different resprouting capacities.…”

“…When lianas suffer falls or crown damage due to falling of their host trees, their stems have a higher probability of producing resprouts and regenerating (Putz, 1984). However, there are variations in the resprouting capacity among plant species (Everham & Brokaw, 1996;Paciorek et al, 2000), including lianas (Gerwing, 2006;Harms & Dallling, 1997;Piovesan et al, 2018). For example, some lianas of the genus Fridericia produced resprouts after experimental cutting, while others did not (Piovesan et al, 2018).…”