In recent years the focus in ecology has shifted from species to a greater emphasis on functional traits. In tandem with this shift, a number of trait databases have been developed covering a range ...of taxa. Here, we introduce the GlobalAnts database.
Globally, ants are dominant, diverse and provide a range of ecosystem functions. The database represents a significant tool for ecology in that it (i) contributes to a global archive of ant traits (morphology, ecology and life history) which complements existing ant databases and (ii) promotes a trait‐based approach in ant and other insect ecology through a broad set of standardised traits.
The GlobalAnts database is unique in that it represents the largest online database of functional traits with associated georeferenced assemblage‐level data (abundance and/or occupancy) for any animal group with 9056 ant species and morphospecies records for entire local assemblages across 4416 sites.
We describe the structure of the database, types of traits included and present a summary of data coverage. The value of the database is demonstrated through an initial examination of trait distributions across subfamilies, continents and biomes.
Striking biogeographic differences in ant traits are highlighted which raise intriguing questions as to the mechanisms generating them.
Representative sampling of ant communities is time-consuming and laborious. Due to their manifold habitat requirements and sociobiological attributes, a suite of sampling methods is necessary to ...detect nearly all ant species in a given habitat. We analysed how well different combinations and intensities of sampling methods are suited to assess ant species richness and community patterns. Sampling occurred at 24 sites in mountain and floodplain habitats in Austria using pitfall traps, Winkler litter extraction, hand sampling of foragers, and colony sampling. Of these, pitfall traps delivered the largest species numbers. We drew 19 subsets of sampling approaches and compared these to the complete data. Many subsets that allowed for substantial reduction of work effort nonetheless reflected well the beta diversity patterns of the whole dataset. In contrast, alpha diversity assessment was more sensitive to reduced sampling effort. Pitfall traps turned out to be indispensable to collect ant species for biodiversity studies, but the optimal combination of sampling methods varied between habitat types. In rugged montane habitats pitfalls should be complemented at least by colony sampling. In floodplain forests the number of pitfall trap replicates can be reduced, but inclusion of Winkler samples is advisable.
The relationship between levels of dominance and species richness is highly contentious, especially in ant communities. The dominance‐impoverishment rule states that high levels of dominance only ...occur in species‐poor communities, but there appear to be many cases of high levels of dominance in highly diverse communities. The extent to which dominant species limit local richness through competitive exclusion remains unclear, but such exclusion appears more apparent for non‐native rather than native dominant species. Here we perform the first global analysis of the relationship between behavioral dominance and species richness. We used data from 1,293 local assemblages of ground‐dwelling ants distributed across five continents to document the generality of the dominance‐impoverishment rule, and to identify the biotic and abiotic conditions under which it does and does not apply. We found that the behavioral dominance–diversity relationship varies greatly, and depends on whether dominant species are native or non‐native, whether dominance is considered as occurrence or relative abundance, and on variation in mean annual temperature. There were declines in diversity with increasing dominance in invaded communities, but diversity increased with increasing dominance in native communities. These patterns occur along the global temperature gradient. However, positive and negative relationships are strongest in the hottest sites. We also found that climate regulates the degree of behavioral dominance, but differently from how it shapes species richness. Our findings imply that, despite strong competitive interactions among ants, competitive exclusion is not a major driver of local richness in native ant communities. Although the dominance‐impoverishment rule applies to invaded communities, we propose an alternative dominance‐diversification rule for native communities.
Our global analysis of more than 1,200 local ant communities reveals that in the absence of non‐native dominant species high levels of behavioral dominance commonly occur with high diversity. Diversity tends to be lower when communities include non‐native dominant species, but in native ant communities it is higher with than without dominant species. Despite strong competitive interactions among ants, our findings indicate that competitive exclusion is not a major driver of local richness in native ant communities. Although the dominance‐impoverishment rule applies to invaded communities, we propose an alternative dominance‐diversification rule for native communities.
Many studies have focused on the impacts of climate change on biological assemblages, yet little is known about how climate interacts with other major anthropogenic influences on biodiversity, such ...as habitat disturbance. Using a unique global database of 1128 local ant assemblages, we examined whether climate mediates the effects of habitat disturbance on assemblage structure at a global scale. Species richness and evenness were associated positively with temperature, and negatively with disturbance. However, the interaction among temperature, precipitation and disturbance shaped species richness and evenness. The effect was manifested through a failure of species richness to increase substantially with temperature in transformed habitats at low precipitation. At low precipitation levels, evenness increased with temperature in undisturbed sites, peaked at medium temperatures in disturbed sites and remained low in transformed sites. In warmer climates with lower rainfall, the effects of increasing disturbance on species richness and evenness were akin to decreases in temperature of up to 9°C. Anthropogenic disturbance and ongoing climate change may interact in complicated ways to shape the structure of assemblages, with hot, arid environments likely to be at greatest risk.
Like many an exclusive club, the medical profession subjects its prospective members to rigorous indoctrination: medical students are overloaded with work, deprived of sleep and normal human contact, ...drilled and tested and scheduled down to the last minute. Difficult as the regimen may be, for those who don't fit the traditional mold—white, male, middle-to-upper class, and heterosexual—medical school can be that much more harrowing. This riveting book tells the tales of a new generation of medical students—students whose varied backgrounds are far from traditional. Their stories will forever alter the way we see tomorrow's doctors. In these pages, a black teenage mother overcomes seemingly insurmountable odds, an observant Muslim dons the hijab during training, an alcoholic hides her addiction. We hear the stories of an Asian refugee, a Mexican immigrant, a closeted Christian, an oversized woman—these once unlikely students are among those who describe their medical school experiences with uncommon candor, giving a close-up look at the inflexible curriculum, the pervasive competitive culture, and the daunting obstacles that come with being "different" in medical school. Their tales of courage are by turns poignant, amusing, eye-opening—and altogether unforgettable.
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