Whether aging forest fragments are able to recover original assemblages or progressively move toward impoverished successional stages remains as an open question. This study tested the hypothesis that seedling assemblages in forest fragments differ from those across mature forest stands and examined to what extent the uncovered patterns supported the notion that edge‐affected habitats tend to support impoverished tree assemblages dominated by pioneer species. We contrasted a series of small forest remnants (3–91 ha) to old‐growth stands located in the largest (ca 3500 ha) and best preserved forest remnant in northeastern Brazil and found that tree seedling assemblages inhabiting forest fragments exhibited reduced species richness (up to 50%) at different spatial scales in comparison to seedling assemblages in mature forest and adult assemblages in both fragments and mature forest stands. Moreover, ordination analyses clearly segregated fragment seedling assemblages in taxonomic/functional terms and segregation correlated to the richness of pioneer species. Seedlings of pioneer species and those bearing medium‐sized seeds (0.6–1.5 cm) increased in fragments, whereas large‐seeded species (1.5–3.0 cm) were reduced by more than a half. Such a multiple‐scale replacement of the old‐growth flora by pioneers was also confirmed by an indicator species analysis and the resulting pioneer indicator species. Our results suggest that small forest fragments support impoverished and distorted seedling assemblages. This floristic/functional drift implies that forest remnants or edge‐affected habitats tend to be dominated by a small set of pioneer tree species rather than supporting a substantial portion of the old‐growth flora as do mature forest stands.

The biodiversity value of human-modified landscapes has become a central question in tropical forest conservation biology, yet the degree to which plant populations and communities are restructured in response to environmental change remains unclear. . Here, we examine the density of 141 tree species in a fragmented Atlantic Forest landscape dominated by a long history of sugar-cane production. We document shifts in population density in small forest fragments to infer on the magnitude of fragmentationrelated effects, and ultimately the structure of future tree assemblages. Both tree seedlings and adults were sampled across 39 0.1-ha plots: 19 in small fragments (<100 ha) and 20 in mature forest stands within the interior of the largest forest remnant of the study landscape (3500 ha). A total of 5,448 seedlings and adults were recorded, with >55% of all tree species exhibiting higher densities in small fragments than in mature forest, particularly pioneers (>60% of all species). Seedlings and adults of these proliferating species differed from species exhibiting population declines in terms of wood density and seed size, respectively. Additionally, pioneers were more abundant than shade-tolerant species, as were hardwood species in the case of seedlings. Tree species showing highest population increases consisted largely of long-lived, lightdemanding canopy species bearing soft or hardwood and small-to-medium sized seeds. Tree assemblage structure also differed in terms of forest habitats with small forest fragments supporting few rare species, whereas the most rapidly proliferating species were much more widespread and abundant in fragments. However 60% of all adult pioneer species recorded in small fragments were not recorded as seedlings in this habitat type, although both seedling and adult assemblages were dominated by pioneer species. Edge-dominated tree assemblages therefore likely experience long term shifts towards greater dominance of long-lived, pioneer canopy species.

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Recent decades have seen increased research interest in the processes and mechanisms related to insect gall richness and host plants. The data set provided here includes 968 records of interactions between galling insects and host plants for the Cerrado biome. The data set comprises 505 species of 222 genera and 67 families of host plants. The botanical families most represented in the data set are Asteraceae, Fabaceae, Myrtaceae, Malpighiaceae, and Melastomataceae, which account for ~48.5% of all records and 52% of the total number of species. The gall‐inducing insects listed in the data set include 48 species of Cecidomyiidae and one species of Tephritidae. This data set is the first to compile inventories of plant‐galling insect communities and information about the diversity and distribution of insect galls and their host plants in the Cerrado. The data set reveals knowledge gaps and opportunities for future research on patterns of diversity and distribution, and provides a basis for generating and testing new ecological hypotheses. Please cite this data paper when using the current data in publications and let us know how the data are used in the publications. There are no copyright restrictions.

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