Explore the vast range of titles available.

BACKGROUND: Ocbil theory aims to develop hypotheses explaining the evolution and ecology of, and best conservation practices for, biota on very old, climatically buffered, infertile landscapes (Ocbils). SCOPE: This paper reviews recent multi-disciplinary literature inspired by or reacting to aspects of Ocbil theory and discusses how it can assist conservation in biodiversity hotspots. CONCLUSIONS: Ocbils occur in at least 12 out of 35 known terrestrial hotspots, but also in other biologically significant sites. Most evidence comes from the Southwest Australian and Greater Cape Floristic Regions, South America’s Pantepui, and the Campo Rupestre of Brazil, though predictions of the theory have been corroborated in 22 sites across South America, Western and Eastern Africa, Southern Asia, and Oceania. Most hypotheses have been corroborated, indicating that Ocbil theory has survived largely intact after 6 years of independent scientific critique, quantitative experimentation, and development. The theory also has been extended to allow identification and characterization of OCBISs (old, climatically-buffered, infertile seascapes), and OCFELs (old, climatically-buffered, fertile landscapes). We illustrate that the principles of Ocbil theory are key to conservation of biodiversity at global scale and provide new directions for research that can improve the theoretical and practical contributions of Ocbil theory.

Botanists, ecologists and evolutionary biologists are familiar with the astonishing species richness and endemism of the fynbos of the Cape Floristic Region and the ancient and unique flora of the kwongkan of south-western Australia. These regions represent old climatically-buffered infertile landscapes (OCBILs) that are the basis of a general hypothesis to explain their richness and endemism. However, few ecologists are familiar with the campo rupestre of central and eastern Brazil, an extremely old mountaintop ecosystem that is both a museum of ancient lineages and a cradle of continuing diversification of endemic lineages. Diversification of some lineages of campo rupestre pre-dates diversification of lowlandcerrado, suggesting it may be the most ancient open vegetation in eastern South America. This vegetation comprises more than 5000 plant species, nearly 15 % of Brazil’s plant diversity, in an area corresponding to 0.78 % of its surface. Reviewing empirical data, we scrutinise five predictions of the OCBIL theory, and show that campo rupestre is fully comparable to and remarkably convergent with both  fynbos and kwongkan, and fulfills the criteria for a classic OCBIL. The increasing threats to campo rupestre are compromising ecosystem services and we argue for the implementation of more effective conservation and restoration strategies.

Saatkamp, A., Cochrane, A., Commander, L., Guja, L., Jimenez-Alfaro, B., Larson, J., Nicotra, A., Poschlod, P., Silveira, F.A.O., Cross, A., Dalziell, E.L., Dickie, J., Erickson, T.E., Fidelis, A., Fuchs, A., Golos, P.J., Hope, M., Lewandrowski, W., Merritt, D.J., Miller, B.P., Miller, R., Offord, C.A., Ooi, M.K.J., Satyanti, A., Sommerville, K.D., Tangney, R., Tomlinson, S., Turner, S., Walck, J.L.

We reviewed the evidence on the role of ants as plant biotic defenses, by conducting meta-analyses for the effects of experimental removal of ants on plant herbivory and fitness with data pooled from 81 studies. Effects reviewed were plant herbivory, herbivore abundance, hemipteran abundance, predator abundance, plant biomass and reproduction in studies where ants were experimentally removed (n = 273 independent comparisons). Ant removal exhibited strong effects on herbivory rates, as plants without ants suffered almost twice as much damage and exhibited 50% more herbivores than plants with ants. Ants also influenced several parameters of plant fitness, as plants without ants suffered a reduction in biomass (-23.7%), leaf production (-51.8%), and reproduction (-24.3%). Effects were much stronger in tropical regions compared to temperate ones. Tropical plants suffered almost threefold higher herbivore damage than plants from temperate regions and exhibited three times more herbivores. Ant removal in tropical plants resulted in a decrease in plant fitness of about 59%, whereas in temperate plants this reduction was not statistically significant. Ant removal effects were also more important in obligate ant-plants (=myrmecophytes) compared to plants exhibiting facultative relationships with hemiptera or those plants with extrafloral nectaries and food bodies. When only tropical plants were considered and the strength of the association between ants and plants taken into account, plants with obligate association with ants exhibited almost four times higher herbivory compared to plants with facultative associations with ants, but similar reductions in plant reproduction. The removal of a single ant species increased plant herbivory by almost three times compared to the removal of several ant species. Altogether, these results suggest that ants do act as plant biotic defenses, but the effects of their presence are more pronounced in tropical systems, especially in myrmecophytic plants.

In plant–animal interactions, species are commonly labeled as either mutualists or antagonists, based on the most common, most studied, or most easily observed outcome. Nevertheless, evidence from simple systems comprising 2–4 species suggests that those labels are an oversimplification: individual species often function in both roles, either simultaneously or at different places or times. We include both mutualistic and antagonistic interactions between mammals and seeds in a multilayer network, to explore for the first time the community-level consequences of the dual roles played by some species. We tested whether negative and positive interactions within a plant–frugivore network are separated into different modules, or whether they overlap due to the presence of frugivores that both kill and disperse seeds. The frugivorous diets of nonvolant small mammals were studied at one dry tropical forest site in southeastern Brazil by analyzing fecal samples from individuals captured in live traps. Seed viability was assessed with a tetrazolium test to determine the outcome of those interactions, as estimated by whether or not seeds survived gut passage. Interactions were analyzed as a weighted multilayer network, subdivided into one potentially mutualistic (live seeds deposited) and one antagonistic (dead seeds deposited) layer. The two layers had similar structure with high overlap between them. Some mammal species exhibited highly central, dual roles, acting both as antagonists and mutualists, in many cases of the same plant species. Dispersal service by most of these small mammals is accompanied by seed destruction, suggesting that the selective pressures exerted by those animals on the plants is much more complex than often assumed. Our results demonstrate that the complexity of plant–frugivore networks can not be fully understood without proper incorporating measures of seed fate following gut passage.

The extent of specialization/generalization continuum in fruit–frugivore interactions at the individual level remains poorly explored. Here, we investigated the interactions between the Neotropical treelet Miconia irwinii (Melastomataceae) and its avian seed dispersers in Brazilian campo rupestre. We built an individual-based network to derive plant degree of interaction specialization regarding disperser species. Then, we explored how intraspecific variation in interaction niche breadth relates to fruit availability on individual plants in varying densities of fruiting conspecific neighbors, and how these factors affect the quantity of viable seeds dispersed. We predicted broader interaction niche breadths for individuals with larger fruit crops in denser fruiting neighborhoods. The downscaled network included nine bird species and 15 plants, which varied nearly five-fold in their degree of interaction specialization. We found positive effects of crop size on visitation and fruit removal rates, but not on degree of interaction specialization. Conversely, we found that an increase in the density of conspecific fruiting neighbors both increased visitation rate and reduced plant degree of interaction specialization. We suggest that tracking fruit-rich patches by avian frugivore species is the main driver of density-dependent intraspecific variation in plants’interaction niche breadth. Our study shed some light on the overlooked fitness consequences of intraspecific variation in interaction niches by showing that individuals along the specialization/generalization continuum may have their seed dispersed with similar effectiveness. Our study exemplifies how individual-based networks linking plants to frugivore species that differ in their seed dispersal effectiveness can advance our understanding of intraspecific variation in the outcomes of fruit–frugivore interactions.

The role of seed germination in contributing to species ecological breadth and geographic distribution is still a matter of debate. Here, we attempted to relate seed germination requirements with ecological breadth in 12 bromeliad species from heterogeneous montane vegetation in southeastern Brazil. Seeds were set to germinate under both light and dark conditions at a broad range of temperatures to determine the breadth of the germination niche. We ran a RLQ analysis based on the matrices of species occurrence, environmental parameters and germination traits and found a significant association between germination traits, and the characteristics of sites where adult plants occur. The variation of germination responses to environmental factors was not random with habitat-generalist plants having broader germination niches and habitat-specialist plants having narrower germination niches. The RLQ analysis showed that substrate moisture and light environment were the most important factors correlated with germination traits. Phylogenetic niche conservatism appears to play a role in the patterns found here, especially in the Tillandsioideae. There is an association between the regeneration niche of a species and its ecological range, and this also provides support for the idea that the regeneration niche may help assemble plant species into heterogeneous, species-rich communities.

Biotic seed dispersal is a key process maintaining biodiversity in tropical forests where most trees produce vertebratedispersed seeds. Existing meta-analyses suggest an overall positive effect of vertebrate gut passage on seed germination, but no significant effects for non-flying mammals. However, previous meta-analyses combined rodents (seed predators) and primates (seed dispersers) into the non-flying mammals category, which may confound specific effects of each group on seed germination. However positive effects of monkeys on germination had previously been found in some studies. Here we disentangle the role of Neotropical primates as contributors to seed dispersal in tropical forests by running a meta-analysis to determine the overall magnitude of gut passage effects on seed germination percentage and mean time to germination. We also compare effect sizes as a function of different feeding guilds, gut complexities, and seed size. Our results show a strong, positive effect of primates on seed germination percentage and on the number of days to first germination. Strictly frugivorous monkeys, the group most threatened by extinction, showed the highest dispersal quality, increasing germination percentage by 75%. Primates that include insects in their diets had no average effect on germination percentage or time. Gut passage had different outcomes on seeds with different sizes; both large and small seeds showed similar increases in germination percentages after gut passage, but only large seeds germinated faster than control seeds after gut passage. Our results show a relevant role for primates in providing high seed dispersal quality and as drivers of forest regeneration. The combined effects of defaunation and forest fragmentation may result in decreased regeneration of trees, which has the potential to affect negatively both forest structure and ecosystem processes. Finally, we provide general guidelines for standardizing research on seed dispersal by primates. Synthesis Consuming fleshy fruits and dispersing seeds is the main ecological service provided by vertebrates to plants. Vertebrate increases seed germination due to treatment given during digestive system passage. Previous metaanalyses suggest an overall positive effect of vertebrate gut passage on germination, but no insights are available on its variation among different functional groups of mammals. Our analyses indicated that gut passage by Neotropical primates increased seed germination. Strict frugivores, the ones most threatened by extinction, were the most efficient. Our results show a relevant role for primates in providing high seed dispersal quality and as drivers of forest regeneration, which can be meaningful for conservation in a community scale.

The Atlantic forest is among the hottest hotspots for biodiversity conservation. Within this biome, inselbergs are isolated granitic and gneiss rocks that rise sharply above the lowland surrounding forests. Due to prevailing stressful conditions and resource paucity of inselbergs, distinguished plant communities are formed in these rocky-associated vegetation, which comprise unusually high levels of endemic and threatened species. Here, we evaluated the importance of competitiveness:stress-tolerance:ruderalism ecological strategies in different vegetation patches on the inselberg, tested for a connection between patch structure and functional traits, and compared the variation in functional traits between native and an exotic species, which represents a major threat to inselberg communities. Despite the stressful conditions of inselbergs, we found a relatively high diversity of ecological strategies, but most species and patches lied between the S and C strategy. The invasive Melinis repens, in turn, was functionally distinctive from native communities, with the predominance of traits associated with ruderalism. We also found that most functional traits significantly correlated with at least one environmental driver, highlighting their role in structuring plant communities in this heterogeneous environment. Since inselberg patches were spatially heterogeneous, and the variation in resource availability implies in favouring different ecological strategies, some patch types were more invasive-prone than others. Our data provide significant advances for identifying the environmental drivers of biological invasion in resource-limited environments. We argue that further trait-based approaches will become critical for developing conservation and management strategies for inselberg plant communities, especially in the context of rapid habitat loss and fragmentation of the Atlantic forest.

Florivory is an ancient interaction which has rarely been quantified due to a lack of standardized protocols, thus impairing biogeographical and phylogenetic comparisons. We created a global, continuously updated, open-access database comprising 180 species and 64 families to compare floral damage between tropical and temperate plants, to examine the effects of plant traits on floral damage, and to explore the eco-evolutionary dynamics of flower–florivore interactions. Flower damage is widespread across angiosperms, but was two-fold higher in tropical vs temperate species, suggesting stronger fitness impacts in the tropics. Flowers were mostly damaged by chewers, but neither flower color nor symmetry explained differences in florivory. Herbivory and florivory levels were positively correlated within species, even though the richness of the florivore community does not affect florivory levels. We show that florivory impacts plant fitness via multiple pathways and that ignoring this interaction makes it more difficult to obtain a broad understanding of the ecology and evolution of angiosperms. Finally, we propose a standardized protocol for florivory measurements, and identify key research avenues that will help fill persistent knowledge gaps. Florivory is expected to be a central research topic in an epoch characterized by widespread decreases in insect populations that comprise both pollinators and florivores.