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Metazoans comprise multiple physical niches ("microenvironments"), each colonized by unique microbiomes that contribute to their hosts' evolutionary dynamics, influencing their health, physiology, and adaptation to changing environments. Most wildlife microbiome studies focus on higher metazoans and multiple host microenvironments, while studies of lower species often concentrate on a single microenvironment, sometimes pooling whole bodies or specimens. This is particularly evident in small-sized animals, such as freshwater meiofaunal invertebrates, thus impeding a holistic understanding of microbiome assembly across host microenvironments and its relation with host population genetics. Leveraging the anostracan fairy shrimp Branchinecta , which has easily discernible organs and expected high levels of intraspecific genetic divergence, we aimed to investigate the microbiome assembly processes and test the phylosymbiosis signal in two microenvironments (gill and intestine) across four host populations of Branchinecta gaini within Maritime Antarctica, using 16S rRNA metabarcoding. Our results showed that the gill and intestine harbor strikingly different microbiomes resulting from the B. gaini ecological filtering of the surrounding environment microbial community. Both microenvironments exhibit their respective core microbiomes, yet the gill's core microbiome is narrower and constitutes a smaller proportion of the overall bacterial community compared to that of the intestine. Within each host population (i.e. each sampling site), the microbiome assembles through distinct eco-evolutionary processes in both microenvironments, mostly stochastically (ecological drift) in the gill and deterministically (variable selection) in the intestine. Across different B. gaini populations, variable selection dominates in driving compositional divergence of both microenvironment microbiomes, although to a lesser extent in the gill. Lastly, our study reveals robust correlation between host intraspecific genetic structure and intestine microbiome composition, providing evidence of phylosymbiosis in anostracans. Contrastingly, phylosymbiosis was less pronounced in the gill microbiome. We discuss the potential differences in ecological filtering between each host microenvironment that may underlie the difference in the strength of phylosymbiosis. Our study highlights the relevance of considering host microenvironment and intraspecific levels in testing the phylosymbiosis hypothesis to better understand the intricate eco-evolutionary relationships between hosts and their microbiomes. [ABSTRACT FROM AUTHOR]

Species that form complex biogenic structures may increase niche space for many others and are assumed to be paramount for whole‐assemblage stability and ecosystem functioning. Because they often ameliorate physical conditions, ecosystem engineering species are also predicted to become more important with environmental stress. Testing this hypothesis, however, has proven difficult because isolating facilitation effects along the entire stress gradient is challenging. Here we addressed motile invertebrate assemblages associated to the mid‐intertidal chthamalid barnacle cover at four rocky shores, either with ('facilitated') or without ('control') a secondary natural cover of small mussels (Mytilaster solisianus and Brachidontes darwinianus). Following a factorial balanced design, replicate samples were taken at three tidal heights in all sites, encompassing a clear gradient of thermal stress and desiccation potential along the vertical range of the mussel‐enriched zone. While observations on general abundance were mostly consistent with stress‐independent facilitation, results for richness, diversity and assemblage structure indicated overarching stress‐dependent responses. All these later three response variables steadily declined from the low to the high level in the control barnacle habitat but remained unaltered in the mussel‐facilitated habitat. Increased facilitation higher on the shore is mostly due to retention of stress‐vulnerable groups such as polychaetes, flatworms and large nematodes which virtually collapse in the higher control habitat, further indicating that mechanisms of mussel facilitation involve relief of environmental stress rather than protection from higher‐order consumers. Our results suggest that mussel ecosystem engineering was fully preserved during the summer season when sampling took place. Ongoing research simulating heat waves compatible to climate‐change scenarios will test whether mussel facilitation would hold over the coming decades. [ABSTRACT FROM AUTHOR]

Metazoans comprise multiple physical niches (“microenvironments”), each colonized by unique microbiomes that contribute to their hosts’ evolutionary dynamics, influencing their health, physiology, and adaptation to changing environments. Most wildlife microbiome studies focus on higher metazoans and multiple host microenvironments, while studies of lower species often concentrate on a single microenvironment, sometimes pooling whole bodies or specimens. This is particularly evident in small-sized animals, such as freshwater meiofaunal invertebrates, thus impeding a holistic understanding of microbiome assembly across host microenvironments and its relation with host population genetics. Leveraging the anostracan fairy shrimp Branchinecta, which has easily discernible organs and expected high levels of intraspecific genetic divergence, we aimed to investigate the microbiome assembly processes and test the phylosymbiosis signal in two microenvironments (gill and intestine) across four host populations of Branchinecta gaini within Maritime Antarctica, using 16S rRNA metabarcoding. Our results showed that the gill and intestine harbor strikingly different microbiomes resulting from the B. gaini ecological filtering of the surrounding environment microbial community. Both microenvironments exhibit their respective core microbiomes, yet the gill’s core microbiome is narrower and constitutes a smaller proportion of the overall bacterial community compared to that of the intestine. Within each host population (i.e. each sampling site), the microbiome assembles through distinct eco-evolutionary processes in both microenvironments, mostly stochastically (ecological drift) in the gill and deterministically (variable selection) in the intestine. Across different B. gaini populations, variable selection dominates in driving compositional divergence of both microenvironment microbiomes, although to a lesser extent in the gill. Lastly, our study reveals robust correlation between host intraspecific genetic structure and intestine microbiome composition, providing evidence of phylosymbiosis in anostracans. Contrastingly, phylosymbiosis was less pronounced in the gill microbiome. We discuss the potential differences in ecological filtering between each host microenvironment that may underlie the difference in the strength of phylosymbiosis. Our study highlights the relevance of considering host microenvironment and intraspecific levels in testing the phylosymbiosis hypothesis to better understand the intricate eco-evolutionary relationships between hosts and their microbiomes.

Abstract Purpose The ecological interdependence between macroorganisms and their microbial communities promotes stable associations over time, potentially leading to their evolutionary co-diversification. The detection of intricate eco-evolutionary interactions between animals and their microbiota is challenging, primarily due to complex bacterial communities related to poorly resolved host population structure. Strikingly, co-diversification in invertebrates, characterized by generally less complex microbiota, remains largely unexplored. Here, we compared the bacterial communities associated with two distinct lineages of Nacella limpets, a dominant shallow water patellogastropod of the Southern Ocean shores with a well-described population structure. Our goals were to elucidate the uniqueness of Nacella microbiota, resulting from an ecological filter that selectively favors certain bacterial taxa. Additionally, we aimed to depict the genetic structure of bacterial symbiont seeking evidence of co-diversification with Nacella. Methods We sequence the V4-V5 regions of the bacterial 16S rRNA gene in three distinct microenvironments associated with Nacella: rock substrate, radula, and whole intestine. These samples were collected from two populations of Nacella deaurata and Nacella concinna, located in the West Antarctic Peninsula and Falkland/Malvinas Islands, respectively. Results We assessed ecological filtering patterns in the limpet microbiota, uncovering unique bacterial communities in both radulas and intestines, with specifically enriched bacterial taxa compared to the surrounding environment. By examining microdiversity patterns of core bacterial taxa, we revealed a deep phylogeographic structure of Psychrilyobacter in Nacella intestines. Conclusion We highlight the Southern Ocean limpets of the Nacella genus as a novel and promising model for studying co-diversification between marine mollusks and their resident microbiota.

Insects harbor diverse assemblages of bacterial and fungal symbionts, which play crucial roles in host life history. Insects and their various symbionts represent a good model for studying host–microbe interactions. Phylosymbiosis is used to describe an eco-evolutionary pattern, providing a new cross-system trend in the research of host-associated microbiota. The phylosymbiosis pattern is characterized by a significant positive correlation between the host phylogeny and microbial community dissimilarities. Although host–symbiont interactions have been demonstrated in many insect groups, our knowledge of the prevalence and mechanisms of phylosymbiosis in insects is still limited. Here, we provide an order-by-order summary of the phylosymbiosis patterns in insects, including Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, and Lepidoptera. Then, we highlight the potential contributions of stochastic effects, evolutionary processes, and ecological filtering in shaping phylosymbiotic microbiota. Phylosymbiosis in insects can arise from a combination of stochastic and deterministic mechanisms, such as the dispersal limitations of microbes, codiversification between symbionts and hosts, and the filtering of phylogenetically conserved host traits (incl., host immune system, diet, and physiological characteristics). [ABSTRACT FROM AUTHOR]

The term 'exaptation' was coined by Gould and Vrba 40 years ago, yet the role that character states which evolved under prior conditions play in novel adaptation to contemporary environments is still a matter of debate. The need to adopt the term 'exaptation' was to replace the term 'preadaptation', which still persists in the literature and may contribute to confusion of the accurate process by which evolution shapes new character states. The emerging discipline of urban evolutionary ecology provides a new lens for the framework by which exaptation and adaptation interplay in helping us to identify phenotypes that are the result of selective pressures in novel environments. The contribution of pre-existing phenotypic variation to evolution in novel environments has long been appreciated. Nevertheless, evolutionary ecologists have struggled with communicating these aspects of the adaptive process. In 1982, Gould and Vrba proposed terminology to distinguish character states shaped via natural selection for the roles they currently serve ('adaptations') from those shaped under preceding selective regimes ('exaptations'), with the intention of replacing the inaccurate 'preadaptation'. Forty years later, we revisit Gould and Vrba's ideas which, while often controversial, continue to be widely debated and highly cited. We use the recent emergence of urban evolutionary ecology as a timely opportunity to reintroduce the ideas of Gould and Vrba as an integrated framework to understand contemporary evolution in novel environments. [ABSTRACT FROM AUTHOR]

Upstream colonizations from islands to continents have played an important role in two major global bird radiations: the oscine passerines and the pigeons. Here, we investigate insular diversification and upstream dispersal dynamics of pigeons (Columbiformes) within the Indo-Australian Archipelago using a supermatrix fossil-calibrated phylogeny and model-based biogeographical analyses. These analyses show that the islands of Melanesia, now centred on New Guinea and considered separately from Australia, have been a centre of pigeon diversification since the Eocene–Oligocene transition (~34 Mya). Geological reconstructions are concordant in suggesting that arc terranes and continental ribbon fragments that underpin the contemporary Melanesian region might have formed extensive archipelagos for much of the Oligocene and Miocene. These islands are also inferred to have functioned as a net source of pigeon lineages for Asia and especially Australia. Arboreal fruit-eating pigeons have colonized nearby continents on multiple occasions yet show little evidence of subsequent radiation. Insular terrestrial pigeons have been largely unable to colonize Asia, and a single Miocene colonization of Australia preceded an endemic radiation. Upstream dispersal may well be a frequent process in the history of the Indo-Australian Archipelago and surrounds, however ecological and environmental factors likely place strong constraints on its success and evolutionary outcomes. [ABSTRACT FROM AUTHOR]

Megaherbivores exert strong top-down influence on the ecosystems they inhabit, yet little is known about the foraging impacts of Asian elephants (Elephas maximus) on the structure of Southeast Asia’s rainforests. Our goal was to document Asian elephants’ dietary composition, selectivity, and foraging impacts in a Sundaic rainforest and test whether these differed between habitats. We conducted controlled direct observations of five wild-born captive elephants feeding on six plant types (bamboo, grass, monocot herbs, palms, lianas, and trees) of different age 2 in two habitats (mature vs. early successional forest) in Krau, Peninsular Malaysia. Palms, trees, and lianas formed the bulk of the elephants’ diet. In the mature forest, elephants showed a strong preference for monocots (preference ratio, PR = 5.1), particularly large palms (PR = 5.4), while trees were negatively selected (PR = 0.14). Conversely, in early successional habitats, large tree saplings were positively selected (PR = 1.6). Elephants uprooted (30%) and broke the main stem (30%) of the dicot trees, mainly large saplings, that they handled. Tree saplings broken by elephants had an average diameter of 1.7 ± 1.1 cm (up to 7 cm), with breaks happening at 1.1 ± 0.5 m of height. We estimated that, in a year, an elephant could damage (i.e., either uproot or break) around 39,000 tree saplings if it fed entirely in mature forest, and almost double the number (73,000) if it fed solely in early successional habitats. Assuming a density of 0.05–0.18 elephants/km2, elephant foraging could damage 0.2–0.6% of the tree sapling population per year. Slow growth rates of understory plants in mature forests could result in negative feedbacks, whereby elephants suppress palms, other monocots, and highly preferred tree species. Alternatively, elephants may initiate positive feedbacks by impeding succession along forest edges and in semi-open environments, thereby increasing the size of gaps and the availability of their preferred foodplants. Overall, our results show that Asian elephants act as ecological filters by suppressing the plants they prefer in Southeast Asia’s rainforests.

Plants minimize fitness losses through grazing by three fundamental strategies: tolerance, avoidance and escape. Annual species have been traditionally assumed to escape grazing through their short life cycle and seed dormancy; however, their grazing response strategies remain almost unexplored. How traits and their coordination affect species' grazing responses, and whether the generalized grazing model, which posits convergent filtering by grazing and drought, is applicable to this ecologically and economically important species group thus remain unclear.We used a trait‐based approach to evaluate grazing response strategies of winter annuals from the Middle East. Across 23 species, we examined the coordination of 16 traits hypothesized to be relevant for grazing responses, and linked them to species' fecundity responses, as proxy for fitness responses, to simulated grazing in controlled conditions, to species' abundance responses to grazing in the field and to species' distribution along a large‐scale rainfall gradient.Winter annuals exhibited both grazing escape and to a lesser extent tolerance indicated by (a) independent coordination of escape and tolerance traits, and (b) maintenance of higher fecundity in species with more pronounced escape or tolerance traits under simulated grazing. In the natural habitat, species with a more pronounced escape but not tolerance strategy maintained higher abundance under grazing in dry habitats, indicating convergent favouring of escape by both grazing and drought. However, this finding at the local scale was not mirrored by a strategy shift along a large‐scale rainfall gradient.Synthesis. The convergent favouring of escape traits by grazing and drought in annuals is consistent with the generalized grazing model. This model, which has been developed for perennials based on the avoidance strategy, can thus be extended to annuals based on escape, a finding that should facilitate projecting consequences of global change in drylands dominated by annuals. [ABSTRACT FROM AUTHOR]

The combined autecology of individual species is expected to reflect the synecology of their respective functional groups and vice versa, but this assumption has been rarely assessed. We estimated this similarity in limiting ecological filters using vegetation survey data from 64 abandoned extracted peatlands in Estonia, which form a 50-year chronosequence of secondary succession. Partial overlap was found between filters predicting the occurrence of individual core species and richness in their respective functional groups. These overlapping filters were microtopographical form (flats, margins, ditches), time since abandonment, and various properties of peat. At the functional group level, time since abandonment and habitat properties showed clear interactions with microform type. Bog species and acidophilous bilocals successfully established on flats and ditch margins when residual peat was acidic and poorly decayed, while species of fens and mineral soils preferentially established in ditches of large extraction fields, where residual peat had higher pH and higher mineral content. We also detected some effects of landscape-level (patch area and forest neighbourhood) and regional filters (continentality); however, their limiting role was inconsistent. Many ecological filters also were shared between functional groups at the species level, but the optimal levels of these filters differed between groups. We conclude that even in species-poor habitats, both the autecology of individual species and the synecology of functional groups should be considered during habitat restoration. In peatland restoration, the following management strategies are advised to direct a faster and more successful trajectory: controlling the depth of peat extraction, partial filling of ditches, introducing plant propagules and managing mineral dust pollution.

Herbaria are renowned as collections of specimens for research in plant taxonomy, plant identification and more recently in plant phylogenetics. The production of Floras and monographs in herbaria is fundamental to the understanding of plant taxonomy and plant biogeography. Herbaria have played an important role in providing the raw geographic data behind plant species distributions which form the basis of the most commonly used biodiversity metric: species richness. Less well recognised is the potential for using comprehensive species checklists, produced by herbaria, as a sampling frame when projecting biodiversity metrics. Functional diversity metrics derived from plant trait values are growing in importance in biodiversity monitoring; however, it is unclear whether the trait-based functional attributes are responsive to changes in species richness in all geographic areas. Modelling of the spatial distribution of trait values is one way to investigate the limits of biodiversity monitoring reliant on trait values. The research outputs of herbaria are arguably an untapped resource of such trait data. Greater digitisation of published Flora treatments as well as continuing digitisation of herbarium specimens is increasingly making these resources more available. With appropriate methods to ameliorate known biases in the species locality and plant trait data held by herbaria, these institutions can play an important role in building spatial models of plant trait distributions. Such models help to establish the relationships between species richness and plant functional diversity metrics in different biomes required for trait-led biodiversity monitoring. Here we present a six-step method to allow data held by herbaria to be used to establish a spatial model of functional diversity metrics at a continental scale. [ABSTRACT FROM AUTHOR]

It had been widely recognized that abiotic and biotic filters determined local community assembly and species diversity hierarchically. However, few studies distinguished the effects of abiotic and biotic filters on species richness and abundance, respectively. We evaluated the difference of abiotic (soil) and biotic (overstorey shrub) filters affecting richness and abundance of understory communities and further disentangle the direct and indirect effects of these filters, focusing on three habitats types defined along an elevational gradient (river bank, floodplain and upper terrace), in a semi-arid riparian vegetation dominated by Caragana aurantiaca Koehne, a dwarf legume shrub, in Yili valley, Sinkiang, China. Understorey herbaceous species richness presented a single effect of soil abiotic filter, which was significantly correlated with soil pH, but not with shrub height and cover, indicating that soil constitutes the main filter determining the species pool available for assembly of understorey vegetation. In contrast to species richness, understorey species abundance presented a joint effect of soil and shrub filters, but the variation explained by the shrub canopies was higher than that of soil variables, indicating overstorey shrub acted as the main filter determining species abundance. In addition, the direct effects of overstorey shrubs through competition and facilitation on understory species abundance are greater than the indirect effects through influencing soil status at local scale. Greater attention to shrub for understory vegetation assembly is needed to assess the role of biotic filter in the semi-arid riparian zone. [ABSTRACT FROM AUTHOR]

A main driver of biodiversity loss is the transformation of pristine habitats into agricultural land, plantations of exotic trees, and settlements. The cloud forest of the Taita Hills in southern Kenya has suffered under such transformation processes. In consequence, remaining forests are small and isolated and often provide degraded forest habitats. We studied butterfly communities in four habitat types, cloud forest, cloud forest margin, exotic tree plantations, and agricultural land. We counted butterflies along transects during the rainy and the dry season. We assessed species traits for each butterfly species found. The four habitat types harbour distinct butterfly communities with only slight overlap among each other. Community compositions differed between the dry and rainy season. Forest specialist butterflies mainly occurred in the interior of the cloud forest, but were also observable along the forest edge. Species richness was highest at the transition between pristine cloud forest and agricultural land. The butterfly community of open agricultural landscapes was dominated by common and widespread East African savannah species, equipped with more elongated wings compared with those found inside the cloud forest. Exotic tree plantations showed a mixed butterfly species composition, consisting of many common and widespread savannah species, but also forest species with comparatively low specialization. In conclusion, typical cloud forest butterflies are on the need for intact cloud forest patches and cannot be compensated by surrogate habitats, such as exotic tree plantations. [ABSTRACT FROM AUTHOR]

Aim: Alexander von Humboldt observed that plant communities on different continents but under similar climatic conditions shared few common species but often contained representatives of the same genera or higher taxonomic groups. To test if this observation can be extended to substrate type, we explored whether a phylogenetic signature could be seen among floras growing on ultramafic substrates that present challenging edaphic conditions for plant growth and are well‐known for their distinctive vegetation. Location: Cuba, Madagascar, New Caledonia. Taxon: Angiosperms. Methods: We compared the floras of Cuba, Madagascar and New Caledonia to test whether the same plant families were under‐ or over‐represented on the ultramafic substrates of the three islands. Results: Pairwise comparisons showed that plant orders and families tended to have the same behaviour on the three islands, i.e. ultramafic substrates filtered (in favour of or against) the same plant groups in the three biogeographical distinct areas. The COM clade (comprising Celastrales, Oxalidales and Malpighiales) appears to be over‐represented on ultramafic substrates in all three islands and contains over half of the world's known nickel hyperaccumulators. Main conclusions: Our analyses provide support for Humboldt's observation by showing that ecological sorting can favour the same plant lineages in similar environments in different biogeographical regions. [ABSTRACT FROM AUTHOR]

The combined autecology of individual species is expected to reflect the synecology of their respective functional groups and vice versa, but this assumption has been rarely assessed. We estimated this similarity in limiting ecological filters using vegetation survey data from 64 abandoned extracted peatlands in Estonia, which form a 50-year chronosequence of secondary succession. Partial overlap was found between filters predicting the occurrence of individual core species and richness in their respective functional groups. These overlapping filters were microtopographical form (flats, margins, ditches), time since abandonment, and various properties of peat. At the functional group level, time since abandonment and habitat properties showed clear interactions with microform type. Bog species and acidophilous bilocals successfully established on flats and ditch margins when residual peat was acidic and poorly decayed, while species of fens and mineral soils preferentially established in ditches of large extraction fields, where residual peat had higher pH and higher mineral content. We also detected some effects of landscape-level (patch area and forest neighbourhood) and regional filters (continentality); however, their limiting role was inconsistent. Many ecological filters also were shared between functional groups at the species level, but the optimal levels of these filters differed between groups. We conclude that even in species-poor habitats, both the autecology of individual species and the synecology of functional groups should be considered during habitat restoration. In peatland restoration, the following management strategies are advised to direct a faster and more successful trajectory: controlling the depth of peat extraction, partial filling of ditches, introducing plant propagules and managing mineral dust pollution. [ABSTRACT FROM AUTHOR]

Abstract: Floral colour is a fundamental signal that shapes plant–pollinator interactions. Despite theoretical reasons why floral colours might shift in representation along biotic and abiotic gradients, few studies have examined community‐level shifts in colour, and even fewer significant patterns have been detected. We examined floral colour on six replicated transects spanning 1,300 m in the Rocky Mountains of Colorado, USA. Along these transects, there is a hypothesized shift from bee‐dominated to fly‐dominated pollination with increasing elevation. The reflectance of flowers of 110 forb and shrub species was measured using a spectrophotometer, and was used to estimate three components of colour (hue, saturation and brightness) in relevant pollinator visual spaces. Percent cover data were collected from 67 sites and used to obtain community‐weighted mean (cwm) estimates of floral colour. We found strong patterns of elevational change in floral colour. Reflectancecwm of shorter wavelengths (UVB through human blue, 300–500 nm) generally decreased linearly with elevation, while reflectancecwm of longer wavelengths (human green through red, 500–700 nm) showed hump‐shaped patterns with highest reflectance at intermediate elevations. With respect to pollinators, saturationcwm increased significantly with elevation in both bee and fly visual spaces, while brightness contrastcwm showed a hump‐shaped pattern in bee space and a decline with elevation in fly visual space. For hue, cover of species perceived as bee‐blue declined with elevation, while cover of bee‐UV‐green species showed a hump‐shaped pattern. In comparison, we detected no elevational shifts in floral hues as perceived by flies. Synthesis. Hue patterns are consistent with the hypothesis that bee pollinators have shaped the geography of floral colour. The roles of fly pollinators and of abiotic drivers are more difficult to infer, although the drop in floral brightness at high elevations is consistent with predictions that low temperatures and more intense ultraviolet radiation should favour increased pigment concentrations there. Our results indicate that floral colour can be dynamic yet predictable across the landscape, a pattern that provides opportunities to tease apart the ecological and evolutionary drivers of this important plant trait. [ABSTRACT FROM AUTHOR]

The restoration of grasslands is a key management practice that supports biodiversity across Europe. On species poor grasslands and ex-arable fields, the establishment of plant species is often limited by the availability of habitat niches, in particular space to germinate. We investigated the impacts of full inversion tillage and its interaction with site conditions and functional traits on the abundance of 51 plant species sown into a 2 ha ex-arable site in Poland. Soils of the donor site were characterized by high levels of heterogeneity in terms of water content and plant availability of N, P and K. One year after sowing the cover of species typical of semi-natural grasslands was significantly higher on the tilled plots than on the non-tilled plots. However, in the case of widespread generalist species the tillage of soil resulted in no significant effect on their establishing percentage cover. The establishment of plants on the tilled area was more successful where soils were relatively rich in mineral N. It was also more successful for species with low Ellenberg’s N values. Species indicative of moist soil established poorly where the soil was tilled. This study has clear implications for the applied restoration of grasslands, demonstrating a vital role of soil tillage to promote the establishment of species typical of semi-natural grasslands. This is particularly important where seed mixtures may contain both desirable and undesirable competitive species that would disproportionately benefit from the absence of tillage management. [ABSTRACT FROM AUTHOR]

Because establishing a new population often depends critically on finding mates, individuals capable of uniparental reproduction may have a colonization advantage. Accordingly, there should be an over-representation of colonizing species in which individuals can reproduce without a mate, particularly in isolated locales such as oceanic islands. Despite the intuitive appeal of this colonization filter hypothesis (known as Baker's law), more than six decades of analyses have yielded mixed findings., We assembled a dataset of island and mainland plant breeding systems, focusing on the presence or absence of self-incompatibility. Because this trait enforces outcrossing and is unlikely to re-evolve on short timescales if it is lost, breeding system is especially likely to reflect the colonization filter., We found significantly more self-compatible species on islands than mainlands across a sample of > 1500 species from three widely distributed flowering plant families (Asteraceae, Brassicaceae and Solanaceae). Overall, 66% of island species were self-compatible, compared with 41% of mainland species., Our results demonstrate that the presence or absence of self-incompatibility has strong explanatory power for plant geographical patterns. Island floras around the world thus reflect the role of a key reproductive trait in filtering potential colonizing species in these three plant families. [ABSTRACT FROM AUTHOR]

Many lotic ecosystems are spatially and temporally heterogeneous but none more so than dryland streams flowing through arid and semi-arid landscapes. Understanding seasonal variation in richness and trait composition is critical to our fundamental understanding of these dynamic stream networks. Here, we analyzed aquatic macroinvertebrate communities within perennial and intermittent reaches in replicate dryland watersheds in southwestern USA across 10 seasons and 4 years. We quantified how hydrology, season, and microhabitat type affected taxa richness and trait composition. Taxa richness was higher in perennial than intermittent reaches, in pools than riffles, and in fall and summer than in spring. The interaction between hydrology and season was important; the difference between fall high and spring low richness was greater in intermittent than perennial streams. Hydrology was the main predictor of trait composition; intermittent streams supported a larger fraction of small taxa, taxa with the ability to undergo diapause, and uni- or multivoltine taxa (i.e., taxa with shorter life cycles). Trait composition did not vary across seasons among perennial reaches whereas the fraction of aerial dispersers appeared to be greater in spring than other seasons among intermittent reaches. Our results were largely consistent with predictions of the habitat templet; r-selected traits were more frequently represented in intermittent communities. The temporal characterization of macroinvertebrate community structure in dryland streams provides a powerful glimpse of how stream communities may respond to a drying climate. [ABSTRACT FROM AUTHOR]

Abstract: Weedy species provide excellent opportunities to examine the process of successful colonization of novel environments. Despite the influence of the sexual system on a variety of processes from reproduction to genetic structure, how the sexual system of species influences weediness has received only limited consideration. We examined the hypothesis that weedy plants have an increased likelihood of being self‐compatible compared with nonweedy plants; this hypothesis is derived from Baker's law, which states that species that can reproduce uniparentally are more likely to successfully establish in a new habitat where mates are lacking. We combined a database of the weed (weedy/nonweedy) and introduction status (introduced/native) of plant species found in the USA with a database of plant sexual systems and determined whether native and introduced weeds varied in their sexual systems compared with native and introduced nonweeds. We found that introduced weeds are overrepresented by species with both male and female functions present within a single flower (hermaphrodites) whereas weeds native to the USA are overrepresented by species with male and female flowers present on a single plant (monoecious species). Overall, our results show that Baker's law is supported at the level of the sexual system, thus providing further evidence that uniparental reproduction is an important component of being either a native or introduced weed. [ABSTRACT FROM AUTHOR]

Aims The study of naturally discontinuous forest systems could help further our understanding of the relative roles of abiotic factors and spatial connectivity in influencing species turnover and plant metacommunity structure, compared to continuous forest formations, where local communities are often arbitrarily defined and where 'mass effects' and source-sink dynamics tend to confound the roles of dispersal and environment. Here we studied a tropical montane landscape where old-growth evergreen forest occurs as patchy formations in a matrix of natural grasslands, to test the influence of environment and connectivity on species turnover and woody plant metacommunity structure. Location Western and southern regions of the Upper Nilgiri Plateau, Western Ghats, southern India. Methods We sampled 85 vegetation plots located across a 600-km2 landscape, assembled environmental data, constructed contrasting spatial connectivity models, including models for the effects of topography on structural connectivity, and used RDA-based variation partitioning to assess the relative influence of environment and space on woody plant metacommunity structure. Results Considering several environmental and multi-scale spatial predictors, we could explain half of the variation in plant community structure. Environmental and habitat factors such as precipitation, temperature seasonality, elevation, fragment size and landscape context play a dominant role, explaining approximately 40% of variation. Spatial predictors based on Euclidean distance performed better than those that accounted for topographic resistance. Spatial predictors accounted for only 9% of the variation in plant metacommunity structure. Conclusion Our results support the species sorting paradigm of metacommunity structure, as abiotic effects and biotic interactions play dominant roles in influencing community structure and species turnover in these old-growth forests, with a comparatively small influence of spatial connectivity. Effective management of woody species diversity would therefore require conservation of these forests across the range of environmental conditions under which they occur. [ABSTRACT FROM AUTHOR]

The species composition within communities is highly dependent on the rate of species immigration and whether immigrating species possess the functional traits required by the prevailing environmental conditions. Once established, random fluctuations in birth and death rates may reduce the diversity of ecologically equivalent species if local populations are not replenished by immigrating individuals. Consequently, three key processes drive community assembly: dispersal limitation, ecological filtering, and ecological drift. However, disentangling the relative contribution of these processes remains a challenge in community ecology. We used a binomial generalized linear mixed model to test whether the occurrences of solitary bees within 46 communities in southeast Norway were driven by (1) dispersal limitation, that is, the geographic distance to the nearest site where conspecifics occurred; (2) ecological filtering, that is, if forb species richness selected for non-Ericaceae-affiliated species; and (3) ecological drift, that is, if small, isolated communities were dominated by regionally common species. The regression slopes from the model for each potential driver of community composition were compared with those expected under a null model, in which species were treated as ecologically equivalent. Both dispersal limitation and ecological filtering influenced the probability of species occurring within communities. The occurrence of species decreased with elevation, and this relationship depended on the relative commonness of species and their floral preferences. For non-Ericaceae-affiliated species, the patterns of occurrence mirrored that expected under the null (neutral) model, resulting in the same patterns as would be expected under ecological drift. In contrast, the response of Ericaceae-affiliated species differed from what would be expected from the null model. Our results also indicate that processes leading to neutral dynamics in species compositions drive a large part of the gradient in species richness in Norwegian bee communities. These processes seem related to sampling effects so that large and interconnected communities have a higher probability of including regionally rare species than small, isolated communities. Our results suggest that targeting habitats—where the influence of ecological filtering is expected to be greater than that of neutral dynamics—can increase the success of habitat management plans aimed at promoting rare species. [ABSTRACT FROM AUTHOR]

Evolutionary processes such as adaptation, ecological filtering, and niche conservatism involve the interaction of organisms with their environment and are thus commonly studied along environmental gradients. Elevational gradients have become among the most studied environmental gradients to understand large-scale patterns of species richness and composition because they are highly replicated with different combinations of geographical, environmental and historical factors. We here review the literature on using elevational gradients to understand evolutionary processes in ferns. Some phylogenetic studies of individual fern clades have considered elevation in the analysis or interpretation and postulated that fern diversification is linked to the colonization of mountain habitats. Other studies that have linked elevational community composition and hence ecological filtering with phylogenetic community composition and morphological traits, usually only found limited phylogenetic signal. However, these studies are ultimately only correlational, and there are few actual tests of the evolutionary mechanisms leading to these patterns. We identify a number of challenges for improving our understanding of how evolutionary and ecological processes are linked to elevational richness patterns in ferns: i) limited information on traits and their ecological relevance, ii) uncertainties on the dispersal kernels of ferns and hence the delimitation of regional species pools from which local assemblages are recruited, iii) limited genomic data to identify candidate genes under selection and hence actually document adaptation and selection, and iv) conceptual challenges in developing clear and testable hypotheses to how specific evolutionary processes can be linked to patterns in community composition and species richness. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Plant distributions have long been understood to be correlated with the environmental conditions to which species are adapted. Climate is one of the major components driving species distributions. Therefore, it is expected that the plants coexisting in a community are reflective of the local environment, particularly climate. METHODS: Presented here is a method for the estimation of climate from local plant species coexistence data. The method, Climate Reconstruction Analysis using Coexistence Likelihood Estimation (CRACLE), is a likelihood-based method that employs specimen collection data at a global scale for the inference of species climate tolerance. CRACLE calculates the maximum joint likelihood of coexistence given individual species climate tolerance characterization to estimate the expected climate. KEY RESULTS: Plant distribution data for more than 4000 species were used to show that this method accurately infers expected climate profiles for 165 sites with diverse climatic conditions. Estimates differ from the WorldClim global climate model by less than 1.5°C on average for mean annual temperature and less than ~250 mm for mean annual precipitation. This is a significant improvement upon other plant-based climate-proxy methods. CONCLUSIONS: CRACLE validates long hypothesized interactions between climate and local associations of plant species. Furthermore, CRACLE successfully estimates climate that is consistent with the widely used WorldClim model and therefore may be applied to the quantitative estimation of paleoclimate in future studies. [ABSTRACT FROM AUTHOR]

Question We tested whether co-existing tree species in tropical dwarf forests were deterministically assembled along gradients of air temperature, relative humidity and light availability, according to two important functional traits, specific leaf area ( SLA) and maximum species height ( Hmax). Location Tropical montane cloud forest, Bawangling Nature Reserve, Hainan Island, south China. Methods Null model analyses were used in conjunction with trait and species composition data collected to test our hypotheses at four plot sizes (25 m2, 100 m2, 400 m2 and 900 m2), addressing whether the consistent importance of variation in SLA and Hmax extends to these unique forests, as well as theoretical predictions concerning how patterns change with plot size. Results Low SLA species were significantly over-represented within forest communities for the two largest plot sizes, and taller-growing tree species were over-represented across all four plot sizes. Plot-level analyses indicated that low SLA species were associated with lower temperatures. Conclusions Our results show that tropical dwarf forests are deterministically assembled with respect to these two traits, and are consistent with other studies indicating that SLA responds to abiotic filters. Co-existing tree species were not significantly divergent for these two traits, indicating that variation in these two traits among trees does not contribute to niche differences (i.e. limiting similarity) and therefore co-existence within forest plots. Finally, our study demonstrates that patterns of community assembly change with plot size; however, trait convergence did not increase with plot size as previously predicted. [ABSTRACT FROM AUTHOR]

A central goal in soil microbial ecology research is to identify the biodiversity patterns and reveal the underlying mechanisms. Long-term soil acidification is known to reduce soil bacterial diversity, but the mechanisms responsible for this pattern have not been well explored. Soil acidification may reduce bacterial richness through ecological filtering (EF). In contrast, two types of processes may promote the maintenance of bacterial richness: species may adapt to the acidic pressure through evolution, and endemic species already adapted to the acidic pressure can colonize the acidified soils through dispersal. To identify the relative contribution of EF and evolution/dispersal (ED), we collected soils with a pH range of 4-7 from different ecosystems, conducted an acidification experiment with a similar pH range in a neutral soil, and proposed a conceptual framework that could distinguish the three potential types of mechanism (neither EF nor ED operate; EF operates alone; ED counteracts some effect of EF). We found that the entire bacterial domain was driven by the third type of mechanism, with ED counteracting about 42.4% (95% confidence interval: 32.7-50.4%) effect of EF. Meanwhile, different bacterial phyla/classes were governed by different types of mechanisms, and the dominant was the third type. Our results highlight the importance of both ecological and evolutionary mechanisms for regulating soil bacterial communities under environmental changes. [ABSTRACT FROM AUTHOR]

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Abstract: Preserving desert plant diversity requires an understanding of the degree to which plant communities are constrained either by suitable habitat or by dispersal limitations. Using a spatially explicit approach, we surveyed diversity in an undisturbed xeric bryophyte community within a regular sampling grid of 1000 adjacent cells. Eigenvector mapping and variation partitioning revealed that spatially independent habitat processes accounted for little of the variation in community composition (2.0%); most variation was attributed either to habitats that were spatially structured (25.6%) or to dispersal independent of habitat (28.0%). At three nested scales, the most influential habitat factors were topography (broad-scale >5 m2), shrub “islands” (meso-scale 1−5 m2), and physical substrate characteristics (fine-scale < 1 m2). Dispersal limitation was less obviously scale-dependent at the community level, yet was important when considering individual species, which showed a wide range of spatial autocorrelation (Moran's I = −0.003–0.601). Our findings suggest that bryophyte diversity is the joint result of dispersal limitations and the distinctive spatially patterned environment of desert shrublands. Therefore, conservation efforts must not only account for dispersal limitations of individual species of concern, but should also seek to retain native shrubs and consequent landscape physiognomy that create bryophyte habitat. [Copyright &y& Elsevier]

Background and Aims Several widespread tree species of temperate forests, such as species of the genus Quercus, produce recalcitrant (desiccation-sensitive) seeds. However, the ecological significance of seed desiccation sensitivity in temperate regions is largely unknown. Do seeds of such species suffer from drying during the period when they remain on the soil, between shedding in autumn and the return of conditions required for germination in spring? Methods To test this hypothesis, the Mediterranean holm oak (Quercus ilex) forest was used as a model system. The relationships between the climate in winter, the characteristics of microhabitats, acorn morphological traits, and the water status and viability of seeds after winter were then investigated in 42 woodlands sampled over the entire French distribution of the species. Key Results The percentages of germination and normal seedling development were tightly linked to the water content of seeds after the winter period, revealing that in situ desiccation is a major cause of mortality. The homogeneity of seed response to drying suggests that neither intraspecific genetic variation nor environmental conditions had a significant impact on the level of desiccation sensitivity of seeds. In contrast, the water and viability status of seeds at the time of collection were dramatically influenced by cumulative rainfall and maximum temperatures during winter. A significant effect of shade and of the type of soil cover was also evidenced. Conclusions The findings establish that seed desiccation sensitivity is a key functional trait which may influence the success of recruitment in temperate recalcitrant seed species. Considering that most models of climate change predict changes in rainfall and temperature in the Mediterranean basin, the present work could help foresee changes in the distribution of Q. ilex and other oak species, and hence plant community alterations. [ABSTRACT FROM PUBLISHER]

Question It is presumed that environmental stress is more pronounced at higher altitudes in Andean forests due to lower rates of temperature-constrained processes of growth, nutrient uptake and decomposition. Because community assembly theory predicts a low variation in viable traits under conditions of strong ecological filtering, we asked if the diversity in plant traits related to productivity and reproduction would decrease upslope. Location Guaramacal National Park in the Andes of Venezuela (9°05-21′N, 70°-20′W). Methods We studied altitudinal patterns in the number of trait states of seven categorical traits found among vascular plants ( DBH ≥ 2.5 cm) in 35 0.1-ha plots between 1330 and 2890 m. Information on plant traits was obtained from literature and herbaria. To test the altitudinal correlations, we permuted the plot-to-species matrix by randomly selecting species from the entire species pool (conserving the species richness and the species-abundance pattern in each plot), applying no restrictions and by creating plot-wise null assemblages of species that most likely occurred near a particular plot. In addition, the altitudinal pattern of trait states was examined using fourth-corner analysis. Results Both null model tests yielded similar results. The trait state diversity in fruit size decreased upslope. Plants with small fruits were mostly, but not exclusively, found at higher altitudes, whereas plants with large fruits occurred only at lower elevations. Leaf size showed more states at higher altitudes but this pattern disappeared when rare leaf size classes were down-weighted. The upslope decrease in fruit size might be explained by the relatively low tree height of the upper montane rain forests, the increased selection for large seeds at high temperatures downslope, and the upslope decrease of large-leaved taxa (in view of Corner's rule). Conclusions The functional diversity of important plant traits changed with altitude at Guaramacal. Altitudinal effects on plant trait responses should be controlled for in studies that monitor the degradation of functional diversity in Andean forests in relation to human influence. [ABSTRACT FROM AUTHOR]

Roadways are increasingly recognized as common points of entry for non-native species into natural habitats in mountainous areas. Studies were conducted within the Greater Yellowstone Ecosystem from 2003 to 2007 to evaluate (1) landscape scale patterns of non-native plant richness along roadways, and (2) local scale factors influencing native and non-native plant richness and cover, and surrogate non-native plant (SNP) emergence in an invaded habitat. At the landscape scale, non-native plant richness decreased with increased elevation and increased distance from the road, and was positively correlated to the proportion of plots with signs of disturbance. Non-native plant richness also varied by habitat type: sagebrush steppe had the highest and alpine the lowest. At the local scale, in sagebrush steppe, SNP emergence was negatively associated with increased distance from the road, and percent cover of litter was positively associated with SNP emergence. The proportion of non-native plant cover and richness decreased, while the proportion of native cover and native species richness increased with distance from road. Our study suggests that landscape scale variables such as elevation and habitat type influence non-native plant success, and that while local conditions adjacent to the road may be favorable for non-native plants, factors which vary at the local scale can also effect non-native plant establishment away from the roadside. This highlights the need for studies to evaluate multiple scales when assessing patterns and processes driving non-native plant invasions, and suggests that sagebrush steppe may be resistant to invasion as long as it remains undisturbed. [ABSTRACT FROM AUTHOR]

The Mediterranean landscape is characterized by a heterogeneous structure: a mosaic of woody plants (trees or shrubs) with scattered patches of herbaceous vegetation. Although the herbaceous and woody patches are adjacent to each other, plant species composition in them is substantially different. This could be attributed to either differences in environmental conditions between patch types (i.e., abiotic filters), or to dispersal limitations caused by the woody plants acting as dispersal filters. In this article, we focus on the relative impact of woody plants, applying these two filter types, in determining plant species composition in Mediterranean woodland. We experimentally manipulated shade and litter cover and examined the effect of each of these factors on plant species composition. We used seed-traps to evaluate seed arrival in the patches, and experimentally removed the shrub canopy to study the effect of the shrub as a physical barrier to seed entry. Results showed that plant species number and composition were not significantly affected by shade and litter manipulation. The number of trapped seeds were significantly higher in the open patches than in the woody patches, and removal of woody plants increased the number of trapped seeds in both open and woody patches, as a result of eliminating the physical obstacle to free seed movement. Our findings show that woody plants affect the herbaceous plant community by influencing seed dispersal, and highlight that they affect other organisms not only by modifying resource availability but also through the creation of a new landscape structure. [ABSTRACT FROM AUTHOR]

Research has delivered convincing findings on the effect of biodiversity on ecosystem functioning and humankind. Indeed, ecosystems provide provisioning, regulating, supporting, and cultural services. The global value of annual ecosystem services of grasslands and rangelands is about US$ 232 ha year. Nevertheless, the precise evaluation of biodiversity benefits remains challenging. This issue is due to valuation methods, subjective assumptions, and complexity of drivers of plant community dynamics. Here, we review the primary factors that influence plant diversity of permanent grasslands, and we describe underlying processes. These factors must indeed be identified to focus policies meant to preserve and restore plant diversity and to advise farmers about efficient decision rules. We show that plant dynamics of permanent grasslands cannot be explained simply by agricultural management rules, e.g., grazing, fertilization, and mowing, implemented at the field scale. The configuration of the surrounding landscape, e.g., landscape heterogeneity, habitat fragmentation, and connectivity, acts as a species filter that defines the regional species pool and controls seed flow. The regional species pool often contains higher species richness in a heterogeneous landscape, because of a higher diversity of suitable habitats. This regional pool could be a major species sources for permanent grasslands according to the seed flow. We discuss the need to consider all of these factors to understand plant species composition of permanent grasslands and the necessity to study plant communities using both taxonomic and functional approaches. In order to report this integrative approach, we propose a conceptual model based on three ecological challenges-dispersal, establishment, and persistence-that are considered to act as filters on plant diversity, and a graphical representation of the complexity of such studies due to the interaction effects between plant dispersal abilities, forage productivity, disturbances induced by farming practices, and landscape heterogeneity on plant diversity. Last, we discuss the ability of farmers to manage each factor and the necessity of such study in the improvement of the current agro-environment schemes efficiency for farmland biodiversity restoration or preservation. [ABSTRACT FROM AUTHOR]

• Premise of the study: Hawaii is home to 238 native and 35 alien fern and lycophyte taxa distributed across steep gradients in elevation and resource availability. The fern flora spans a wide range of growth forms, with extraordinary diversity in morphology and plant size. Yet the potential factors underlying this diversity have remained enigmatic. • Methods: We used a trait database generated from the most recent and comprehensive survey of Hawaiian ferns and lycophytes to test hypotheses of size-scaling and trait associations with environment and growth form as factors underlying this diversity. We also tested relationships among morphology, taxon abundance and distribution and identified key differences between native and alien taxa. • Key results: Strong trait--trait relationships included geometric scaling of plant dimensions with a tendency for more divided fronds in larger ferns. Trait--environment relationships independent of size included more divided fronds at higher elevation, longer blades in shaded habitats, and fronds with shorter stipes and fewer pinnae in drier habitats. Growth forms differed in mean size with epiphytic and epipetric taxa smaller than terrestrial ferns. Plant size was independent of taxon abundance and distribution across islands, and native and alien ferns did not differ in mean size. Alien taxa were more abundant, especially at lower elevations, apparently due to human land use. • Conclusions: These relationships point to linkages of fern form and demography with biogeography and highlight potential flora-scale physiological and morphological adaptations in ferns across contrasting environments. [ABSTRACT FROM AUTHOR]

Closely related species that occur together in commu- nities and experience similar environmental conditions are likely to share phenotypic traits because of the process of environmental filtering. At the same time, species that are too similar are unlikely to co-occur because of competitive exclusion. In an effort to explain the coexistence of 17 oak species within forest communities in North Central Florida, we examined correlations between the phylogenetic relatedness of oak species, their degree of co-occurrence within communities and niche overlap across environmental gradients, and their similarity in ecophysiological and life-history traits. We show that the oaks are phylogenetically overdispersed because co-occurring spe- cies are more distantly related than expected by chance, and oaks within the same clade show less niche overlap than expected. Hence, communities are more likely to include members of both the red oak and the oak clades than only members of one clade. This pattern of phylogenetic overdispersion arises because traits important for habitat specialization show evolutionary convergence. We hypothesize further that certain conserved traits permit coexistence of distantly related congeners. These results provide an explanation for how oak diversity is maintained at the community level in North Central Florida. [ABSTRACT FROM AUTHOR]

• This is the first study focused on the structure of multi-species avian dawn choruses in urban areas. • At intra-urban areas dawn choruses were modular but not ordered in time. • At peri-urban areas dawn choruses were modular and showed a temporally structured order. • Dawn choruses from both conditions had low spectral vocalization overlap. • Random phylogenetic structure was observed for choruses at both conditions. Living in the city represents a great challenge for organisms that are exposed to the novel environmental conditions inherent to urbanization. Recent studies have highlighted the ecological impact that urbanization poses on the acoustic phenotype and singing routines of birds. However, the organization and structure of avian dawn choruses in urban settings remains largely unexplored. In this study, we assessed the temporal structure of avian dawn choruses in an intra-urban area and a peri-urban forest using bipartite network analyses. We predicted a random network structuring of dawn choruses across time at the intra-urban area, while expected a non-random structure (i.e., modular or nested) at the peri-urban forest. While we detected different groups of birds vocalizing together temporarily, following a modular pattern in both studied conditions, only the one from the peri-urban forest showed a sequential temporal structure of dawn choruses. Avian dawn choruses from both intra-urban and peri-urban areas were mainly comprised by phylogenetically unrelated species (i.e., random phylogenetic structure), also exhibiting low overlap on singing frequencies. Our results are in agreement with the temporal partitioning of the acoustic space in the peri-urban forest. Our findings also suggest that the absence of temporally-structured modules of bird dawn choruses at heavily-urbanized areas could be related to the depauperization of the avian community at intra-urban areas as a sequel of ecological filtering, as well as the consequent importance of the dominance of the acoustic space by invasive species. [ABSTRACT FROM AUTHOR]