Disturbance as a driver of trait assembly in liana communities in a semi-deciduous Atlantic Forest

Abstract

Subtropical forests have been under constant pressure due to drastic changes in land use, fragmentation, and logging. These impacts can alter the canopy cover, structure, species composition, and functional characteristics of plant communities. Here, we assess whether structural and functional properties of the liana community change in forests that were differently disturbed in the past. For this purpose, six 1-ha plots were established in closed and open canopy forests in the Atlantic Forest of Northern Argentina. Lianas were measured and identified and plant material was collected to determine specific leaf area, leaf dry matter content, and wood density. Species richness of lianas was similar, but the abundance and basal area were significantly higher in open canopy than in closed canopy plots. This difference was primarily the result of a higher abundance of scramblers in open canopy plots, while tendrilled lianas were negatively affected by low tree density and basal area. The abundance of large scrambler lianas was lower in sites with high tree density. On the other hand, scramblers had lower wood density and leaf dry matter content than tendril climbers and twiners had the lowest specific leaf area values. Consequently, liana communities in open canopy forests were associated with a rapid resource acquisition strategy and lower functional diversity which could be possibly driven by changes in environmental variables typical of large gaps (light availability, temperature, and soil fertility). Our results highlight a shift in liana climbing mechanisms and in the function of liana communities in disturbed forest, becoming dominated by lianas with similar functional traits. Future studies should assess the relative importance of changes of liana communities shedding light on climbing-type-level effects on tree growth and forest functioning.