•Monitoring organism responses to urbanization is critical in the face of increasing urbanization around the world.•Broad-scale, repeatable methods, are needed.•Broad-scale empirical citizen science ...data highlight the ability to measure urban tolerance of birds.
Understanding species-specific responses to urbanization is essential to mitigate and preserve biodiversity in the face of increasing urbanization, but a major challenge is how to estimate urban tolerances for a wide array of species applicable over disparate regions. A promising approach is to assess urban tolerance by integrating geo-referenced information on species detections from citizen science data with estimations of urbanization intensity based on remotely-sensed night-time lights. While such citizen science urbanness scores (CSUS) are cost-effective, intuitive, and easily-repeatable anywhere in the world, whether the scores accurately describe urban tolerance still awaits empirical verification. By analysing >900 bird species worldwide, we find that CSUS correlates well with a standard measure of urban tolerance based on changes in abundance between urbanized and non-urbanized nearby habitats. Our analyses show that there is substantial variability in the relationship between these two metrics, but nevertheless highlights the potential for the CSUS approach in the future. Future improvements to the index, including incorporating rare species, and understanding the influence of intra-specific variability in response to urbanization, will be necessary to maximize the broad utility of the approach.
The life-history basis of behavioural innovations Sol, Daniel; Sayol, Ferran; Ducatez, Simon ...
Philosophical transactions of the Royal Society of London. Series B. Biological sciences,
03/2016, Letnik:
371, Številka:
1690
Journal Article
Recenzirano
Odprti dostop
The evolutionary origin of innovativeness remains puzzling because innovating means responding to novel or unusual problems and hence is unlikely to be selected by itself. A plausible alternative is ...considering innovativeness as a co-opted product of traits that have evolved for other functions yet together predispose individuals to solve problems by adopting novel behaviours. However, this raises the question of why these adaptations should evolve together in an animal. Here, we develop the argument that the adaptations enabling animals to innovate evolve together because they are jointly part of a life-history strategy for coping with environmental changes. In support of this claim, we present comparative evidence showing that in birds, (i) innovative propensity is linked to life histories that prioritize future over current reproduction, (ii) the link is in part explained by differences in brain size, and (iii) innovative propensity and life-history traits may evolve together in generalist species that frequently expose themselves to novel or unusual conditions. Combined with previous evidence, these findings suggest that innovativeness is not a specialized adaptation but more likely part of a broader general adaptive system to cope with changes in the environment.
Although urbanization is a major threat to biodiversity, some species are able to thrive in cities. This might be because they have specific adaptations to urban conditions, because they are able to ...cope with artificial habitats in general or because they are generalists that can live in a wide range of conditions. We use the latest version of the IUCN database to distinguish these possibilities in 25,985 species of the four classes of terrestrial vertebrates with the help of phylogenetically controlled methods. We first compare species occurrence in cities with that of the five other artificial habitats recognized by the IUCN and use principal components analyses to ask which of these most resembles cities. We then test whether urban species have a wider habitat breadth than species occurring in other, non-urban, artificial habitats, as well as species that occur only in natural habitats. Our results suggest that the proportion of terrestrial vertebrates that occur in urban environments is small and that, among the species that do occur in cities, the great majority also occur in other artificial habitats. Our data also show that the presence of terrestrial vertebrates in urban habitats is skewed in favor of habitat generalists. In birds and mammals, species occurrence in urban areas is most similar to that of rural gardens, while in reptiles and amphibians, urban areas most resemble pasture and arable land. Our study suggests that cities are likely not unique, as is often thought, and may resemble other types of artificial environments, which urban exploiters can adapt to because of their wide habitat breadth.
Islands have long been recognized as key contributors to biodiversity because they facilitate geographic isolation and ecological divergence from mainland ancestors. However, island colonization has ...traditionally been considered an evolutionary dead-end process, and its consequences for continental biodiversity remain understudied. Here, we use the evolutionary radiation of Columbiformes (i.e. pigeons and doves) to examine if ecological niche shifts on islands shaped biological diversification and community composition on continents. We show that the colonization of islands by continental, terrestrial-foraging lineages led to the exploitation of a new ecological niche (i.e. arboreal foraging). This transition towards arboreal foraging was associated with evolutionary adaptation towards a new morphological optimum. In addition, arboreal-foraging lineages of islands experienced an increase in speciation rates, which was associated with successful range expansions to other islands as well as back colonization of continents. Our results provide empirical evidence that diversification on continents can only be fully understood when studying the diversification processes that took place on islands, challenging the view of islands as mere sinks of evolutionary diversity.
Despite growing interest in the evolution of enlarged brains, the biological significance of brain size variation remains controversial. Much of the controversy is over the extent to which brain ...structures have evolved independently of each other (mosaic evolution) or in a coordinated way (concerted evolution). If larger brains have evolved by the increase of different brain regions in different species, it follows that comparisons of the whole brain might be biologically meaningless. Such an argument has been used to criticize comparative attempts to explain the existing variation in whole-brain size among species. Here, we show that pallium areas associated with domain-general cognition represent a large fraction of the entire brain, are disproportionally larger in large-brained birds and accurately predict variation in the whole brain when allometric effects are appropriately accounted for. While this does not question the importance of mosaic evolution, it suggests that examining specialized, small areas of the brain is not very helpful for understanding why some birds have evolved such large brains. Instead, the size of the whole brain reflects consistent variation in associative pallium areas and hence is functionally meaningful for comparative analyses.
Aim
Understanding how extinction has occurred in the recent past is crucial to unravel its main drivers as well as to implement effective conservation practices to minimize global biodiversity loss. ...It has long been hypothesized that extinction risk is not randomly distributed among traits of species. However, the actual traits making species more prone to extinction may have been overlooked because already extinct species are often not considered in comparative analyses of extinction risk. We characterized the drivers of extinction in a cosmopolitan bird clade, including Holocene and contemporary extinctions potentially related to human impacts and provided evidence of an ‘extinction selectivity’ in species traits.
Location
Global.
Time period
Anthropocene.
Major taxa studied
Columbiformes clade, pigeons and doves.
Methods
We constructed a new phylogenetic hypothesis of the Columbiformes, a cosmopolitan bird clade consisting of 33 recently extinct and 351 extant species. Then, we integrated data on geography, behaviour and morphology to reveal the drivers of extinction risk. We used phylogenetic generalized least square models to test the effect of geography, behaviour and morphology in the risk of extinction and identified differences in the drivers of extinction when including versus excluding recently extinct species.
Results
Our analysis revealed that Columbiformes endemic to islands with ground‐foraging habits, weak flying abilities, migratory behaviour and larger body sizes are more vulnerable to extinction. Our results also show that excluding recently extinct species identifies extinction drivers different from those when including recently extinct species.
Main conclusions
Only by accurately identifying the traits that increase extinction risk we can develop targeted conservation measures that promote the long‐term persistence of threatened species. Extinction selectivity has important implications for the conservation of biological communities and ultimately ecosystem functioning, considering the critical role Columbiformes often play as seed dispersers.
Evidence is accumulating that species traits can spur their evolutionary diversification by influencing niche shifts, range expansions, and extinction risk. Previous work has shown that larger brains ...(relative to body size) facilitate niche shifts and range expansions by enhancing behavioral plasticity but whether larger brains also promote evolutionary diversification is currently backed by insufficient evidence. We addressed this gap by combining a brain size dataset for > 1900 avian species worldwide with estimates of diversification rates based on two conceptually different phylogenetic-based approaches. We found consistent evidence that lineages with larger brains (relative to body size) have diversified faster than lineages with relatively smaller brains. The best supported trait-dependent model suggests that brain size primarily affects diversification rates by increasing speciation rather than decreasing extinction rates. In addition, we found that the effect of relatively brain size on species-level diversification rate is additive to the effect of other intrinsic and extrinsic factors. Altogether, our results highlight the importance of brain size as an important factor in evolution and reinforce the view that intrinsic features of species have the potential to influence the pace of evolution.
Anthropogenic activities and intensive farming are causing nitrate pollution in groundwater bodies. These aquifers are drained by springs which, in the Mediterranean region, act as refugia for ...preserving biodiversity of species that need continuous water. Some springs are also used for drinking water for wild animals, livestock and humans, so if their water quality is compromised it can become a threat to public health. However, the impact of nitrate pollution on these biotic communities remains unknown. We sampled 338 assemblages of aquatic and semi-aquatic bryophytes (i.e., hygrophytic mosses and liverworts) growing in springs in a gradient of water conductivity, nitrate concentration and climate and distributed across the north-east of the Iberian Peninsula to investigate the impact of nitrate pollution on the diversity of bryophytes and moss functional traits in Mediterranean springs. Based on previous literature suggesting that increased nitrogen load decreases biodiversity in grasslands and freshwater ecosystems, we hypothesised that water nitrate pollution in springs decreases bryophyte diversity at the local and regional scales. Our results indicated that, at the local scale (spring), nitrate pollution reduced the number and the likelihood of finding a rare species in springs. Rare species were found in 4% of the springs with nitrate above 50 mg L−1 but in 32% of the springs with nitrate below 50 mg L−1. Moss, liverwort and overall bryophyte diversity were not directly affected by nitrate at the local scale but nitrate consistently decreased diversity of mosses, liverworts and rare bryophyte species at the regional scale. We also found that warmer and drier springs presented fewer bryophyte species. Our results show that the combination of nitrate pollution, increasing temperature and drought could severely threaten bryophyte diversity in Mediterranean springs. Our results indicate that the absence of rare bryophytes could be used as a bioindicator of nitrate pollution in springs.
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•Intensive farming is increasing groundwater nitrate pollution in many regions.•We studied 338 springs across a gradient of climate, nitrate and water conductivity.•Nitrate pollution was associated with decreased bryophyte diversity in springs.•Rare bryophyte species were not present in highly polluted springs.•Mosses living in springs polluted with nitrate were larger and less dense.
Seasonal migration is an underappreciated driver of animal diversification. Changes in migratory behaviour may favour the establishment of sedentary founder populations and promote speciation if ...there is sufficient reproductive isolation between sedentary and migratory populations. From a systematic literature review, we here quantify the role of migratory drop-off-the loss of migratory behaviour-in promoting speciation in birds on islands. We identify at least 157 independent colonization events likely initiated by migratory species that led to speciation, including 44 cases among recently extinct species. By comparing, for all islands, the proportion of island endemic species that derived from migratory drop-off with the proportion of migratory species among potential colonizers, we showed that seasonal migration has a larger effect on island endemic richness than direct dispersal. We also found that the role of migration in island colonization increases with the geographic isolation of islands. Furthermore, the success of speciation events depends in part on species biogeographic and ecological factors, here positively associated with greater range size and larger flock sizes. These results highlight the importance of shifts in migratory behaviour in the speciation process and calls for greater consideration of migratory drop-off in the biogeographic distribution of birds.
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