Publications
The role of land-use history in driving successional pathways and its implications for the restoration of tropical forests
Catarina C. Jakovac, André B. Junqueira, Renato Crouzeilles, Marielos Peña-Claros, Rita C. G. Mesquita and Frans Bongers
Biological Reviews, 2021, doi: 10.1111/brv.12694
Secondary forests are increasingly important components of human-modified landscapes in the tropics. Successional pathways, however, can vary enormously across and within landscapes, with divergent regrowth rates, vegetation structure and species composition.
We review the literature aiming to provide a comprehensive understanding of the mechanisms underlying the long-lasting effects of land use on tropical forest succession and to discuss its implications for forest restoration. We organize it following a framework based on the hierarchical model of succession and ecological filtering theory.
This review shows that our knowledge is mostly derived from studies in Neotropical forests regenerating after abandonment of shifting cultivation or pasture systems. The literature shows that (i) species availability to succession is affected by transformations in the landscape that affect dispersal, and by management practices and seed predation. Species establishment and performance are dependent on resistance to management practices, tolerance to (modified) soil conditions, herbivory, competition with weeds and invasive species, and facilitation by remnant trees. (ii) Structural and compositional divergences at early stages of succession remain for decades, suggesting that early communities play an important role in governing further ecosystem functioning and processes during succession. Management interventions at early stages could help enhance recovery rates and manipulate successional pathways. (iii) The combination of local and landscape conditions defines the limitations to succession and therefore the potential for natural regeneration to restore ecosystem properties effectively.

Forest structure drives changes in light heterogeneity during tropical secondary forest succession
Tomonari Matsuo, Miguel Martínez-Ramos, Frans Bongers, Masha T. van der Sande, Lourens Poorter
Journal of Ecology, 2021
The rationale. Light is a key resource for tree performance and hence, tree species partition spatial and temporal gradients in light availability. Although light distribution drives tree performance and species replacement during secondary forest succession, we yet lack understanding how light distribution changes with tropical forest development.
Aims. This study aims to evaluate how changes in forest structure lead to changes in the vertical- and horizontal light heterogeneity during tropical forest succession.
Approach. We described successional patterns in light using a chronosequence approach in which we compared 14 Mexican secondary forest stands that differ in age (8-32 years) since agricultural abandonment. For each stand, we measured vertical light profiles in 16 grid cells, and structural parameters (diameter at breast height, height, and crown dimensions) for each tree.
Findings.
- During succession, the inflection points of the vertical light gradient (i.e., the absolute height at which 50% relative light intensity is attained) rapidly moved towards higher heights in the first 20 years, indicating that larger amounts of light are intercepted by canopy trees.
- Light attenuation rate (i.e., the rate of light extinction) decreased during succession due to slower accumulation of the crown area with height.
- Understory light intensity and heterogeneity slightly decreased during succession because of an increase in crown size and a decrease in lateral gap frequency.
- Understory relative light intensity was 1.56% at 32 years after abandonment.
- These changes in light conditions are largely driven by the successional changes in forest structure, as basal area strongly determines the height where most light is absorbed, whereas crown area, and to a lesser extent crown length, determine light distribution.
Implications. The fast forest development during tropical secondary forest succession leads to the fast changes in light conditions and more light heterogeneity, which can increase the proportion of shade-tolerant late-successional species over time, and hence tree species diversity.
