Tree species vary widely in their tolerance for liana infestation: A case study of differential host response to generalist parasites

Abstract

1. Lianas are structural parasites of trees and reduce individual host tree growth, survival and fecundity. Thus, liana infestation is expected to affect tree population growth rates, with potentially different effects in different species depending on the frequency of liana infestation and the impact of liana infestation on population growth rates. Previous studies have documented the myriad negative effects of lianas on trees and variation in liana infestation among tree species; however, no study has quantified the impact of liana infestation on individual tree species population growth rates. Lianas are increasing in abundance in multiple Neotropical sites, which may have profound consequences for tree species composition if lianas differentially affect host tree species population growth.2. Here, we use long-term data to evaluate the effects of liana infestation on the reproduction, growth, survival and ultimately population growth rates of dozens of tree species from Barro Colorado Island, Panama. We then test whether liana infestation affects tree species differentially with respect to two axes of life-history variation: adult stature and position along the fast-slow axis, a measure of shade tolerance.3. Liana infestation decreased tree growth, survival and reproduction, with the strongest effects on survival in fast-growing, light-demanding species and on reproduction in large-statured species. In combination, these effects reduced tree population growth rates such that liana-infested populations declined by an average of 1.4% annually relative to conspecific liana-free populations. The reduction in population growth rates was greatest among fast-growing species and smaller in slow-growing species. Synthesis.Our results demonstrate that liana infestation has strong negative effects on tree population growth rates, which vary systematically among tree species with tree life history. The finding that liana infestation is more harmful to fast-growing tree species appears to be at odds with the general expectations in the literature.We propose that this is likely due to survivorship bias, as infestation greatly decreases survival in fast-growing species such that the observable sample is biased towards those that survived and liana-free. In combination with data on how tree Paper previously published as Standard Paper 782 | Journal of Ecology VISSER Et al. | MATERIALS AND METHODS | Study siteBCI is a 1,562-ha island covered with lowland moist tropical forest located in Gatun Lake in central Panama (9°9′N, 79°51′W). Annual species vary in liana infestation rates, these results provide a basis for predicting the impacts of changes in liana abundance on tree species composition. K E Y W O R D S apparent competition, Barro Colorado Island, global change, integral projection model, Panama, parasite-mediated competition, plant demography, reproduction, survivorship bias, tropical forests | 783 Journal of Ecology VISSER Et al.

Modeling the impact of liana infestation on the demography and carbon cycle of tropical forests

“…The model predicts differential impacts of lianas on trees of different functional types: lianas negatively impact pioneer trees and favor shade‐tolerant trees. Although this differentiated effect of liana infestation is still debated (Schnitzer & Carson, ), a recent study by Visser et al () tends to corroborate the model output by finding that shade tolerance correlates with tolerance of liana infestation. In the model, the low density‐independent mortality of shade‐tolerant species translates to longer residence times than those shown by the occupying lianas.…”

Lianas have a seasonal growth advantage over co‐occurring trees

“…), and recruitment (Grauel and Putz , Schnitzer and Carson ), and thus it seems unlikely that lianas would have little effect on tree demography (Visser et al. 2018a).…”

A comprehensive synthesis of liana removal experiments in tropical forests

“…, Visser et al . ). Additionally, many of the large‐scale and influential studies on lianas have examined only very large lianas ( e.g ., Phillips et al .…”