Biology subjects

Schaefer, H. M.

Publications and source records attributed to Schaefer, H. M..

3 recordsLinked to original sources

bioRxiv2025

Restoration legacy, forest cover and elevation shape frugivory in a tropical landscape

Assisted and passive natural restoration are widely applied strategies for forest restoration, yet their focus on tree recovery makes their effectiveness in restoring broader biodiversity unclear. Assuming that tree recruitment will rebuild whole ecosystems overlooks other taxa and their interactions, and thus underestimates key components of biodiversity like biotic interactions. To address this gap, we assessed two complementary questions: (i) how frugivory reestablishes and varies among assisted restoration and natural regeneration areas, and (ii) how local conditions (fruit availability, elevation, and time since restoration) and landscape context (forest cover and fragmentation) influence frugivory beyond restoration strategies. This was done by implementing a dummy fruit experiment in a tropical landscape in southeast Ecuador that considered two fruit sizes. Dummy fruit handling did not differ between assisted and naturally regenerated areas, indicating that neither restoration strategy was superior in promoting frugivory. Instead, landscape context played a central role. Fruit handling increased with old-growth forest cover and elevation, and declined with increasing forest fragmentation, highlighting the importance of habitat amount and connectivity for interaction recovery. Fruit size further shaped frugivory patterns, particularly in restored areas, where larger fruits were handled more frequently. Overall, our results show that restoration outcomes for frugivory depend less on restoration strategy alone and more on landscape structure and environmental context. By demonstrating the utility of artificial fruits as a rapid and practical tool to assess interaction recovery, this study highlights the need to move beyond vegetation-based metrics and explicitly incorporate biotic interactions into the evaluation of forest restoration success.

ecology↗

bioRxiv2025

Acoustic indices predict recovery of tropical bird communities for taxonomic and functional composition

Quantifying the success of biodiversity restoration is a major challenge in the UN Decade on Ecosystem Restoration. We evaluated the potential of acoustic indices to predict the recovery success of bird communities within abandoned agricultural areas. Using audio recordings from a lowland tropical forest region, we identified 334 bird species and calculated established acoustic indices. Community composition was analyzed using Hill numbers, accounting for incomplete sampling. Acoustic indices effectively predicted independent species data (R2 = 0.59-0.76), capturing not only taxonomic but also functional and phylogenetic composition. Taxonomic composition was best predicted for common and dominant species, while functional and phylogenetic compositions were more accurately predicted for rare and common species. In addition, community composition was strongly influenced by the surrounding habitat. Our findings demonstrate that a small set of acoustic indices, once validated by stratified ground truth data, provides a powerful tool for assessing restoration success over large tropical areas, even for functional composition of rare tropical birds.

ecology↗

bioRxiv2024

Reassembly of a tropical rainforest ecosystem: A new chronosequence in the Ecuadorian Choco tested with the recovery of tree attributes

From hunting and foraging to clearing land for agriculture, humans modify forest biodiversity, landscapes, and climate. Forests constantly undergo disturbance-recovery dynamics and understanding them is a major objective of ecologists and conservationists. Chronosequences are a useful tool for understanding global restoration efforts. They represent a space-for-time substitution approach suited for the quantification of the resistance of ecosystem properties to withstand disturbance and the resilience of these properties until reaching pre-disturbance levels. Here we introduce a newly established chronosequence with 62 plots (50 50 m) in active cacao plantations and pastures, early and late regeneration, and mature old-growth forests, across a 200 km2 area in the extremely wet Choco rainforest. Our chronosequence covers by far the largest total area of plots compared to others in the Neotropics. Plots ranged from 159-615 masl in a forested landscape with 74 {+/-} 2.8 % forest cover within a 1-km radius including substantial old-growth forest cover. Land-use legacy and regeneration time were not confounded by elevation. We tested how six forest structure variables (maximum tree height and DBH, basal area, number of stems, vertical vegetation heterogeneity, and light availability), aboveground biomass (AGB), and rarefied tree species richness change along our chronosequence. Forest structure variables, AGB, and tree species richness increased with regeneration time and are predicted to reach similar levels to those in old-growth forests after ca. 30-116, 202, and 108 yrs, respectively. Compared to previous work in the Neotropics, old-growth forests in Canande accumulate high AGB that takes one of the largest time spans reported until total recovery. Our chronosequence comprises one of the largest tree species pools, covers the largest total area of regenerating and old-growth forests, and has higher forest cover than other Neotropical chronosequences. Hence, our chronosequence can be used to determine the time for recovery and stability (resistance and resilience) of different taxa and ecosystem functions, including species interaction networks. This integrative effort will ultimately help to understand how one of the most diverse forests on the planet recovers from large-scale disturbances.

ecology↗