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Data from: Effects of forest degradation on Amazonian ferns in a land-bridge island system as revealed by non-specialist inventories

Cite this dataset

Storck-Tonon, Danielle et al. (2021). Data from: Effects of forest degradation on Amazonian ferns in a land-bridge island system as revealed by non-specialist inventories [Dataset]. Dryad.


Background: Tropical deforestation and degradation worldwide have rapidly outpaced biodiversity field sampling. No study to date has assessed the effects of insular habitats induced by hydroelectric dams on Amazonian understorey plants. Fern community responses to anthropogenic effects on tropical forest islands can be efficiently revealed through simple and cheap, yet informative protocols that can be applied by non-specialists. 

Aims: This study seeks to both understand the drivers of fern and lycophyte assemblages on forest islands and investigate the relative costs and effectiveness of a simplified sampling protocol that can be implemented by non-specialists and has potential to be used to crowdsource ecological field data acquisition.

Methods: Fern and lycophytes species were sampled by a non-specialist in 17 quarter-hectare plots on 10 forest islands at the lake of Balbina Hydroelectric Dam, central Amazonia. Sampling was carried out opportunistically during a field expedition planned to conduct tree inventory on permanent plots. We used a set of locally measured or GIS-derived predictors for each of the surveyed sites. We used Principal Coordinates Analysis and Generalized Linear Mixed Models (GLMMs) to further assess the influence of predictors on patterns of fern species richness and composition.

Results: A total of 286 photographed individual ferns or lycophytes represented 23 taxa. The average number of taxa per plot was 6.1 on islands and 14.3 in the mainland. The insular species pool was a subset of the mainland pool of fern species. Richness was positively related to island size and negatively related to isolation and fire severity. Area, isolation and fire severity significantly explained variation in community composition. The relative cost of the non-specialist picture-based fern protocol was very modest (in our case, only 4% of the total expedition budget), even compared to the typically low cost of alternative orthodox field campaigns.

Conclusion: Fern community structure in this forest archipelago was primarily driven by island size, isolation and fire disturbance. We show that a simple sampling protocol carried out by a non-specialist can lead to inexpensive and highly reliable ecological data. This opens an avenue for crowdsourcing ecological fern data collections using a citizen science approach.