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Aim: Understanding the mechanisms determining species richness is a primary goal of biogeography. Richness patterns of sub‐groups within a taxon are usually assumed to be driven by similar processes. However, if richness of distinct ecological strategies respond differently to the same processes, inferences made for an entire taxon may be misleading. We deconstruct the global lizard assemblage into functional groups and examine the congruence among richness patterns between them. We further examine the species richness – functional richness relationship to elucidate the way functional diversity contributes to the overall species richness patterns. Location: Global. Methods: Using comprehensive biological trait databases we classified the global lizard assemblage into ecological strategies based on body size, diet, activity times and microhabitat preferences, using Archetypal Analysis. We then examined spatial gradients in the richness of each strategy at the one‐degree grid cell, biome, and realm scales. Results: We found that lizards can best be characterized by seven "ecological strategies": scansorial, terrestrial, nocturnal, herbivorous, fossorial, large, and semi‐aquatic. There are large differences among the global richness patterns of these strategies. While the major richness hotspot for lizards in general is in Australia, several strategies exhibit highest richness in the Amazon Basin. Importantly, the global maximum in lizard species richness is achieved at intermediate values of functional diversity and increasing functional diversity further result in a slow decline of species richness. Main conclusions: The deconstruction of the global lizard assemblage along multiple ecological axes offers a new way to conceive lizard diversity patterns. It suggests that local lizard richness mostly increases when species belonging to particular ecological strategies become hyper‐diverse there, and not because more ecological types are present in the most species rich localities. Thus maximum richness and maximum ecological diversity do not overlap. These results shed light on the global richness pattern of lizards, and highlight previously unidentified spatial patterns in understudied functional groups. [ABSTRACT FROM AUTHOR]

Aim The species population density-range size relationship posits that locally abundant species are widely distributed. However, this proposed pattern has been insufficiently tested. The few tests conducted were usually limited in scale and gave conflicting results. We tested the generality of the positive population density-range size relationship. We then studied whether similar environmental niche requirements are correlated with range size and with population density to search for mechanisms driving the hypothesized link between population density and range size. Location Worldwide. Methods We collected data on population density, range size and environmental niche for a global dataset of 192 lizard, 893 bird and 350 mammal species. Assessing the relationship between population density and range size and environmental niche parameters, we corrected for phylogenetic relationships, body mass, diet and study area. Results Our findings reveal that density had a weak negative correlation with bird range size and was unrelated to lizard and mammal range size. These trends were consistent at the global scale and across the biogeographical realms. Range size was related to relatively similar environmental niche parameters in all groups. Population density, however, was explained by taxon-specific factors and was therefore unrelated to range size by common causation. Main conclusions We suggest that the positive relationship between population density and range size identified in previous studies might be an artefact arising through incomplete sampling of range sizes. Our results indicate that the mechanisms shaping population density and range size may be independent. [ABSTRACT FROM AUTHOR]

Aim The origins of islands influence island colonization and radiation dynamics, thus exerting differential selection pressures on the species that inhabit them. The occurrence of lower numbers of predator and competitor species on islands than the mainland selects for 'slow' life-history attributes (the 'island syndrome'). Animals colonizing, and radiating on, oceanic islands probably face more novel environments than do those inhabiting continental fragment and land-bridge islands. We hypothesized that oceanic island endemics will show the slowest life histories, whereas land-bridge island species will resemble mainland species the most. We predicted that species on old, small and isolated islands will also have slow life histories. Location World-wide. Methods We assembled life-history data for 540 mainland and 319 insular endemic lizard species. We tested whether clutch size, brood frequency, hatchling mass and productivity differed between islands of different origin and between islands and the mainland. We controlled for female size, for latitude and for phylogenetic relationship using the R package caper. In addition, we tested the influences of island age, area and isolation on species life histories. Results Oceanic island endemics have the smallest clutches and the largest offspring, and, together with continental fragment island endemics, lay most frequently. Clutch size, brood frequency and productivity increase with increasing island age. Isolation and area have little effect on lizard life history. Main conclusions Our findings support the proposition that selection pressure differs across island type. The predator-poor environments on oceanic islands select for few, large offspring, while the predator-rich environments of the mainland and land-bridge islands select for many, small offspring. Island geological origin creates the environment within which evolution takes place, and thus plays a major role in life-history evolution. As islands grow older, lizards adapt by increasing their yearly reproductive effort. [ABSTRACT FROM AUTHOR]

Aim Islands are thought to promote correlated ecological and life-history shifts in species, including increased population density, and an infrequent production of few, large, offspring. These patterns are collectively termed 'the island syndrome'. We present here the first, phylogenetically informed, global test of the 'island syndrome' hypothesis, using lizards as our model organisms. Location World-wide. Methods We assembled a database containing 641 lizard species, their phylogenetic relationships, geographic ranges and the following life-history traits: female mass, clutch size, brood frequency, hatchling body mass and population density. We tested for life-history differences between insular and mainland forms in light of the island syndrome, controlling for mass and latitude, and for phylogenetic non-independence. We also examined the effects of population density and, in insular endemics, of island area, on lizard reproductive traits. Results We found that insular endemic lizards lay smaller clutches of larger hatchlings than closely related mainland lizards of similar size, as was expected by the island syndrome. In general, however, insular endemics lay more frequently than mainland ones. Species endemic to small islands lay as frequently as mainland species. Continental and insular lizards have similar productivity rates overall. Island area had little effect on lizard reproductive traits. No trait showed association with population density. Main conclusions Island endemic lizards mainly follow the island syndrome. We hypothesize that large offspring are favoured on islands because of increased intra-specific aggression and cannibalism by adults. Stable populations on islands lacking predators may likewise lead to increased intra-specific competition, and hence select for larger hatchlings that will quickly grow to adult size. This view is supported by the fact that lizard populations are denser on islands - although population density per se was uncorrelated with any of the traits we examined. [ABSTRACT FROM AUTHOR]