Aim: The pattern of increasing biological diversity from high latitudes to the equator [latitudinal diversity gradient (LDG)] has been recognized for > 200 years. Empirical studies have documented this pattern across many different organisms and locations. Our goal was to quantify the evidence for the global LDG and the associated spatial, taxonomic and environmental factors. We performed a meta-analysis on a large number of individual LDGs that have been published in the 14 years since Hillebrand's ground-breaking meta-analysis of the LDG, using meta-analysis and metaregression approaches largely new to the fields of ecology and biogeography.Location: Global. Major taxa studied: Bacteria, protists, plants, fungi and animals. Methods:We synthesized the outcomes of 389 individual cases of LDGs from 199 papers published since 2003, using hierarchical mixed-effects meta-analysis and multiple meta-regression.Additionally, we re-analysed Hillebrand's original dataset using modern methods. Results:We confirmed the generality of the LDG, but found the pattern to be weaker than was found in Hillebrand's study. We identified previously unreported variation in LDG strength and slope across longitude, with evidence that the LDG is strongest in the Western Hemisphere. Locational characteristics, such as habitat and latitude range, contributed significantly to LDG strength, whereas organismal characteristics, including taxonomic group and trophic level, did not. Modern meta-analytical models that incorporate hierarchical structure led to more conservative and sometimes contrasting effect size estimates relative to Hillebrand's initial analysis, whereas metaregression revealed underlying patterns in Hillebrand's dataset that were not apparent with a traditional analysis. Main conclusions:We present evidence of global latitudinal, longitudinal and habitat-based patterns in the LDG, which are apparent across both marine and terrestrial realms and over a broad taxonomic range of organisms, from bacteria to plants and vertebrates. We used the search phrase, "latitud* NEAR/20 (diversity OR biodiversity OR "species richness")" for Web of Science and altered it according to the search methods required for the other databases (see Supporting Information Appendix S1). We included studies written in English in relevant disciplines (e.g., ecology, evolution), excluding non-relevant fields.The literature search yielded 3,817 studies, of which we screened the abstracts. We excluded studies in which: (a) species richness was measured over < 108 of latitude, (b) species richness was measured in fewer

The theories developed in ecological stoichiometry (ES) are fundamentally based on traits. Traits directly linked to cell/body stoichiometry, such as nutrient uptake and storage, as well as the associated trade-offs, have the potential to shape ecological interactions such as competition and predation within ecosystems. Further, traits that indirectly influence and are influenced by nutritional requirements, such as cell/body size and growth rate, are tightly linked to organismal stoichiometry. Despite their physiological and ecological relevance, traits are rarely explicitly integrated in the framework of ES and, currently, the major challenge is to more closely inter-connect ES with trait-based ecology (TBE). Here, we highlight four interconnected nutrient trait groups, i.e., acquisition, body stoichiometry, storage, and excretion, which alter interspecific competition in autotrophs and heterotrophs. We also identify key differences between producer-consumer interactions in aquatic and terrestrial ecosystems. For instance, our synthesis shows that, in contrast to aquatic ecosystems, traits directly influencing herbivore stoichiometry in forested ecosystems should play only a minor role in the cycling of nutrients. We furthermore describe how linking ES and TBE can help predict the ecosystem consequences of global change. The concepts we highlight here allow us to predict that increasing N:P ratios in ecosystems should shift trait dominances in communities toward species with higher optimal N:P ratios and higher P uptake affinity, while decreasing N retention and increasing P storage.

Species are expected to alter their ranges as climates change. Climate-induced range expansions of predators could threaten evolutionarily na ï ve prey populations, leading to high mortality at the invasion front. If prey can apply existing defenses against local predators to novel predation threats induced by climate change, mortality threats will be less than expected. Here, we examine if spotted salamander larvae Ambystoma maculatum from populations that coexist with native red-spotted newts Notophthalmus viridescens survive better when exposed to a novel predator, the marbled salamander Ambystoma opacum . We show that regional mean winter temperatures warmed 2.0 ° C over 116 yr in the region, and that A. opacum survival increases in ponds with higher winter temperatures. Hence as winters continue to warm, this apex predator will likely colonize ponds north of their current range limit. Next, we performed common garden experiments to determine if local adaptations to native N. viridescens and exposure to A. opacum or N. viridescens kairomones (predator chemical cues) altered A. maculatum survival in predation trials. We did not fi nd evidence for local adaptation to N. viridescens . However, A. maculatum from high-N. viridescens ponds that were reared with A. opacum kairomones suff ered signifi cantly higher mortality from the native predator N. viridescens . Th is outcome suggests an unanticipated interaction between local adaptation and plastic responses to novel kairomones from a potentially range-expanding predator. Current projections of biodiversity losses from climate change generally ignore the potential for eco-evolutionary interactions between native and range-expanding species and thus could be inaccurate.

Many planktonic consumers alter their behavior depending on the concentration of food in the environment, but responses to changes in food quality, as characterized by its elemental stoichiometry, are less well understood. Because of different nutritional demands across life history stages, consumer's responses to prey quality may vary across ontogeny. We build on previous observations of consumer selectivity and responses to prey presence by examining responses of displacement and movement patterns to prey stoichiometry. We used high‐speed videography to quantify displacement and movement patterns of the marine copepod, Acartia tonsa, as they varied with elemental content of microalgal food offered during preconditioning and during imaging trials. Life stages were sensitive to different nutrient elements in prey, with movement in copepodites generally varying with nitrogen content, and in adults with both nitrogen and phosphorus content. Net displacement was lower when adults and copepodites were offered fully replete and nitrogen‐replete food, respectively. Displacement of adults was more sensitive to the quality of food offered during preconditioning, and displacement of copepodites was affected by food quality during both preconditioning and trials. Naupliar displacement and movement patterns were generally insensitive to food quality. Only adults significantly altered movement patterns associated with feeding in response to food quality; adult helical swimming significantly increased in the treatments in which stoichiometrically replete food was offered in both preconditioning and behavioral trials. Older stages of A. tonsa alter movement in response to food quality in ways that may allow the selective use of patches of high‐quality prey.