Evaluating plant lineage losses and gains in temperate forest understories: a phylogenetic perspective on climate change and nitrogen deposition.

Global change has accelerated local species extinctions and colonizations, often resulting in losses and gains of evolutionary lineages with unique features. Do these losses and gains occur randomly across the phylogeny? We quantified: temporal changes in plant phylogenetic diversity (PD); and the phylogenetic relatedness (PR) of lost and gained species in 2672 semi-permanent vegetation plots in European temperate forest understories resurveyed over an average period of 40 yr. Controlling for differences in species richness, PD increased slightly over time and across plots. Moreover, lost species within plots exhibited a higher degree of PR than gained species. This implies that gained species originated from a more diverse set of evolutionary lineages than lost species. Certain lineages also lost and gained more species than expected by chance, with Ericaceae, Fabaceae, and Orchidaceae experiencing losses and Amaranthaceae, Cyperaceae, and Rosaceae showing gains. Species losses and gains displayed no significant phylogenetic signal in response to changes in macroclimatic conditions and nitrogen deposition. As anthropogenic global change intensifies, temperate forest understories experience losses and gains in specific phylogenetic branches and ecological strategies, while the overall mean PD remains relatively stable.

Les changements globaux accélèrent les processus de colonisation et d'extinction locales d'espèces, aboutissant à des gains ou à des pertes de lignées évolutives uniques. Ces gains et pertes se produisent-ils de manière aléatoire dans l'arbre phylogénétique ? Nous avons mesuré: les changements de diversité phylogénétique; et la parenté phylogénétique des espèces végétales gagnées ou perdues dans 2672 placettes semi-permanentes disposées dans le sous-bois de forêts tempérées d'Europe sur une période moyenne de 40 ans. Une fois corrigée par la richesse spécifique, la diversité phylogénétique a légèrement augmenté au cours du temps dans les différentes placettes. Les espèces perdues ont une plus grande parenté phylogénétique que les espèces gagnées. Les espèces gagnées sont donc issues d'un plus grand nombre de lignées évolutives que les espèces perdues. Certaines lignées ont gagné ou perdu davantage d'espèces que ce qui est prédit par le hasard : les Ericaceae, les Fabaceae et les Orchidaceae ayant davantage perdu, tandis que les Amaranthaceae, les Cyperaceae, et les Rosaceae ont plus gagné. Il n'y a pas de signal phylogénétique des gains ou pertes d'espèces en réponse aux changements de conditions macroclimatiques ou des dépôts atmosphériques d'azote. Alors que les changements globaux d'origine anthropique s'intensifient, les sous-bois des forêts tempérées connaissent des gains et des pertes de certaines lignées évolutives et de certaines stratégies écologiques, sans que la diversité phylogénétique moyenne ne s'en trouve véritablement affectée.

El cambio global ha acelerado las extinciones y colonizaciones a escala local, lo que a menudo ha supuesto pérdidas y ganancias de linajes evolutivos con características únicas. Ahora bien, ¿estas pérdidas y ganancias ocurren aleatoriamente a lo largo de la filogenia? Cuantificamos: los cambios temporales en la diversidad filogenética de las plantas; y la relación filogenética de las especies perdidas y ganadas en 2.672 parcelas de vegetación semipermanente en sotobosques templados europeos y re-muestreadas durante un período promedio de 40 años. Al controlar por las diferencias en la riqueza de especies, la diversidad filogenética aumentó ligeramente con el tiempo y entre parcelas. Además, las especies perdidas dentro de las parcelas exhibieron un mayor grado de relación filogenética que las especies ganadas. Esto implica que las especies ganadas se originaron en un conjunto de linajes evolutivos más diversos que las especies perdidas. Ciertos linajes también perdieron y ganaron más especies de las esperadas aleatoriamente: Ericaceae, Fabaceae y Orchidaceae experimentaron pérdidas y Amaranthaceae, Cyperaceae y Rosaceae mostraron ganancias. Las pérdidas y ganancias de especies no mostraron ninguna señal filogenética significativa en respuesta a los cambios en las condiciones macro-climáticas y la deposición de nitrógeno. A medida que se intensifica el cambio global antropogénico, los sotobosques temperados experimentan pérdidas y ganancias en ramas filogenéticas y estrategias ecológicas específicas, mientras que la diversidad filogenética media general permanece relativamente estable.

Network structure of avian mixed-species flocks decays with elevation and latitude across the Andes.

Birds in mixed-species flocks benefit from greater foraging efficiency and reduced predation, but also face costs related to competition and activity matching. Because this cost-benefit trade-off is context-dependent (e.g. abiotic conditions and habitat quality), the structure of flocks is expected to vary along elevational, latitudinal and disturbance gradients. Specifically, we predicted that the connectivity and cohesion of flocking networks would (i) decline towards tropical latitudes and lower elevations, where competition and activity matching costs are higher, and (ii) increase with lower forest cover and greater human disturbance. We analysed the structure of 84 flock networks across the Andes and assessed the effect of elevation, latitude, forest cover and human disturbance on network characteristics. We found that Andean flocks are overall open-membership systems (unstructured), though the extent of network structure varied across gradients. Elevation was the main predictor of structure, with more connected and less modular flocks upslope. As expected, flocks in areas with higher forest cover were less cohesive, with better defined flock subtypes. Flocks also varied across latitude and disturbance gradients as predicted, but effect sizes were small. Our findings indicate that the unstructured nature of Andean flocks might arise as a strategy to cope with harsh environmental conditions. This article is part of the theme issue 'Mixed-species groups and aggregations: shaping ecological and behavioural patterns and processes'.

AVONET: morphological, ecological and geographical data for all birds.

Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species-level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity.

Taxonomic and Phylogenetic Determinants of Functional Composition of Bolivian Bat Assemblages.

Understanding diversity patterns and the potential mechanisms driving them is a fundamental goal in ecology. Examination of different dimensions of biodiversity can provide insights into the relative importance of different processes acting upon biotas to shape communities. Unfortunately, patterns of diversity are still poorly understood in hyper-diverse tropical countries. Here, we assess spatial variation of taxonomic, functional and phylogenetic diversity of bat assemblages in one of the least studied Neotropical countries, Bolivia, and determine whether changes in biodiversity are explained by the replacement of species or functional groups, or by differences in richness (i.e., gain or loss of species or functional groups). Further, we evaluate the contribution of phylogenetic and taxonomic changes in the resulting patterns of functional diversity of bats. Using well-sampled assemblages from published studies we examine noctilionoid bats at ten study sites across five ecoregions in Bolivia. Bat assemblages differed from each other in all dimensions of biodiversity considered; however, diversity patterns for each dimension were likely structured by different mechanisms. Within ecoregions, differences were largely explained by species richness, suggesting that the gain or loss of species or functional groups (as opposed to replacement) was driving dissimilarity patterns. Overall, our results suggest that whereas evolutionary processes (i.e., historical connection and dispersal routes across Bolivia) create a template of diversity patterns across the country, ecological mechanisms modify these templates, decoupling the observed patterns of functional, taxonomic and phylogenetic diversity in Bolivian bats. Our results suggests that elevation represents an important source of variability among diversity patterns for each dimension of diversity considered. Further, we found that neither phylogenetic nor taxonomic diversity can fully account for patterns of functional diversity, highlighting the need for examining different dimensions of biodiversity of bats in hyperdiverse ecosystems.