BackgroundInvasive plant species strongly affect native plant communities, often with strong influences belowground. Some native plants respond with rapid trait change from multigenerational interactions with invasives, including via root biomass allocation. Native plant root allocation responses to multigenerational invasive exposure are poorly typified, and researchers have yet to summarise whether resource availability mediates the responses of native plants that have co-occurred with invasive plant species (invader-experienced) and those that have not (invader-experienced).AimsEvaluate root partitioning from invader-experienced and invader-na & iuml;ve native plant populations, in experiments in which native plants were grown alone or with the co-occurring invasive species at varying resource levels.MethodsUse 242 effect sizes on 17 native species in meta-analysis models to compare root allocation between invader-experienced and invader-na & iuml;ve and under varying resource levels.ResultsI found that differences in response to the presence or absence of multigenerational invasive exposure were only apparent when testing different resource levels. Specifically, when grown alone, invader-experienced plants had greater root allocation under stress, whereas invader-na & iuml;ve plants had lower root allocation under resource limitation.ConclusionInteractions with invasive plant species produced adaptive responses in native plant species to resources which are observed even without interactions with invasives. This indicates a significant effect of invasive species below-ground and calls for more research assessing eco-evolutionary root trait responses to coexistence by native species with invasive species.
BackgroundOne well-established hypothesis to explain high epiphyte diversity in the Neotropics is the vertical niche differentiation hypothesis (VNDH). The VNDH posits that Neotropical epiphytic biodiversity is driven by the differentiation of epiphytes into specialised niches throughout the forest canopy. However, few studies have taken an experimental approach to testing this hypothesis.AimsTo determine whether epiphyte morphospecies exhibit vertical niche specialisation and whether shifts in vertical position affect their survival.MethodsWe assessed the vertical distribution of 35 common epiphyte morphospecies across 30 focal host trees to characterise naturally occurring variability in epiphyte distributions. We then experimentally transplanted individuals from their original canopy positions to the understorey to test the effects of altered vertical strata on survival.ResultsNone of the 35 morphospecies were strictly specialised by height zone and many were non-uniformly distributed throughout the canopy. Survival rates declined with increasing original canopy height - epiphytes found higher in the canopy were less likely to persist after relocation to the understorey.ConclusionOur results support the notion of vertical stratification among Neotropical vascular epiphytes and experimentally demonstrate survival consequences linked to this stratification. These findings contribute to understanding mechanisms underlying tropical epiphyte diversity and offer insights for forest managers interested in the sustainable horticulture of tropical epiphytes.
BackgroundUnderstanding plant community assembly in montane ecosystems is vital, yet mechanisms in semiarid regions remain poorly resolved, particularly regarding cryptic environmental filters.AimsWe aimed to (1) determine whether lack of environment - abundance correlation reflects stochasticity or competition, and (2) evaluate whether phylogenetic structure is a more sensitive indicator of cryptic filters in semiarid mountains.MethodsIn 25 plots, we recorded species abundance and calculated phylogenetic metrics (NRI, NTI) from regional phylogeny. Mantel tests compared abundance - phylogeny correlations. Canonical Correspondence Analysis (CCA), PERMANOVA, and NMDS linked environmental variables (soil moisture, pH, EC; elevation, slope) to abundance. PERMANOVA and Principal Coordinates of Phylogenetic Structure (PCPS) assessed environment - phylogeny relationships.ResultsAbundance showed no significant correlation with environmental variables (CCA/PERMANOVA/NMDS). Mantel tests confirmed no abundance - phylogeny correlation. Phylogenetic overdispersion (negative NRI/NTI) indicated competitive exclusion. Phylogeny revealed significant filtering by soil moisture and pH (PERMANOVA) and moisture/pH/EC (PCPS) - undetected by abundance methods. Topography showed no effect.ConclusionPhylogeny revealed dual assembly dynamics: competitive overdispersion and cryptic filtering by soil moisture/pH. This shows the greater sensitivity of phylogeny, detecting deterministic filters where abundance data showed only weak trends. In semiarid mountains, local edaphic gradients override topography impact, underscoring essential role of phylogeny in revealing assembly mechanisms.
BackgroundPhylogeny-based assessments of Holocene vegetation are rare. They are important for understanding eco-evolutionary dynamics of species assembly under environmental changes and ever-increasing anthropogenic pressure.AimsTo reveal any spatio-temporal variation in the phylogenetic dispersion (PD, mean phylogenetic distance of co-occurring taxa) in angiosperm pollen assemblages in mainland Europe and North America and their relationship with regional climate and anthropogenic influence.MethodsUsing 12,250 and 14,898 fossil pollen assemblages from Europe and North America, respectively, we analysed family level spatio-temporal variation in Holocene PD by hierarchical generalised linear models and tested its concordance with Holocene climate and anthropogenic influence by Procrustes randomisation tests.ResultsHolocene PD exhibited a reverse-humped pattern along latitudinal gradients in both continents. A longitudinal pattern in Holocene PD in Europe was not pronounced. However, in North America, it declined irregularly along the gradient from west to east. PD in both continents varied significantly during the early- and late-Holocene in concordance with Holocene climate and anthropogenic influences. Complex fine-scale spatio-temporal variations in PD were also pronounced.ConclusionProfound and complex Holocene eco-evolutionary changes in angiosperm assemblages in Europe and North America correspond largely to changes in extrinsic and intrinsic drivers and mechanisms of ecological changes. Future environmental changes of similar or a greater magnitude may drive further changes in the phylogenetic structure of the assemblages. A more detailed study of their eco-evolutionary dynamics requires detailed spatio-temporal assemblage data with precise taxonomy and census, and a detailed and robust species-level phylogeny of the species pool.
Background While woody plants and their relationship with fertile islands (nutrient hot-spots) have been extensively studied, how the fertile-island effect on arbuscular mycorrhizal fungi (AMF) differs among shrub species remains unexplored. Aims We compared AMF communities (root colonisation and spore density) in three shrub species with distinct phylogenetic lineages and architectural traits: Onobrychis cornuta (compact cushion-forming, deciduous), Berberis integerrima (open canopy, deciduous) and Juniperus sabina (procumbent, evergreen). Methods At 13 sites where all three shrub species co-occurred, root segments and soil samples were collected to quantify AMF root colonisation, spore density and relate them to soil variables. For comparison, spore density was also determined in the adjacent herbaceous patches. Results Soil under O. cornuta and J. sabina had the highest spore densities (2019 and 1976 spores 100-g(-1) soil, respectively), while herbaceous patches had the lowest (1130 spores100-g(-1) soil). O. cornuta roots had the greatest AMF root colonisation (79.5%) and B. integerrima (41.3%) had the least. Correlations between soil parameters and AMF colonisation and spore density differed with shrub species and soil variables. Conclusions Species-specific AMF traits reflect fungal adaptation to microhabitat conditions under shrub canopies. These findings can guide shrub selection for restoring degraded subalpine ecosystems by aligning fungal symbionts with optimal environmental niches.
Background Plant growth form diversity stems from a wide range of life history traits, yet vegetative architecture remains relatively understudied. Aims This study investigated the genus Thottea, a small group of understorey plants in tropical forests, to examine how shifts in growth form relate to variations in plant architecture, woodiness and stem biomechanics. Methods We analysed plant architecture, stem biomechanics, and anatomical features for nine Thottea species from lowland tropical forests in Peninsular India. A molecular phylogenetic framework was used to assess shifts in growth form and related traits. Results All Thottea species displayed a uniform architecture defined by (a) mixed axes (i.e. a single meristem determine both trunk and branch), (b) basal reiteration and (c) repetition of elementary modules. Growth form variations arose from distinct combinations of woodiness, below-ground structures and reiteration processes. Conclusion Key traits such as adaptive reiteration and basal reiteration, above-ground woodiness, mechanical reinforcement and plagiotropy are pivotal to the adaptation of species of Thottea to disturbed and shaded understorey habitats. These trait syndromes represent important life history strategies linked to the challenges of understorey life and have evolutionary implications across the genus.
Background High Nature Value farmland (HNVf) supports biodiverse, semi-natural habitats through extensive farming but is increasingly threatened in Ireland by land intensification and abandonment. Results-based payment schemes (RBPS) aim to maintain and enhance these habitats, yet their broader biodoversity benefits remain unclear. Aims This study examined the relationship between an RBPS scoring system developed for the protected hen harrier (Circus cyaneus) and semi-natural grassland plant communities. Methods Thirty grassland fields spanning a gradient of RBPS ecological condition scores from (0-10) were surveyed. Vegetation surveys were carried out in three 2 m & times; 2 m quadrats per fieldalong a 'W' transect walk, supplemented with additional environmental data as proxies for environmental conditions and management pressure. Non-metric Multidimensional Scaling was used to analyse species composition, and fields were assigned to a vegetation type using the Irish Vegetation Classification ERICA tool. Results Higher RBPS scores were positively associated with greater number and cover of positive indicator species, increased bryophyte cover, and higher floristic diversity indices. Lower scoring fields were associated with greater cover of negative indicator species, increased rush cover and higher Ellenberg's Nitrogen and Reaction values. Eight wet grassland community types were identified. Conclusions Our findings indicate that an RBPS designed to incentivise ecological conditions for a target raptor species can also reflect wider plant diversity, supporting multiple ecosystem services in HNVf systems.
BackgroundGlobal coffee production faces increasing threats from climate change, including rising temperatures, prolonged droughts, and the spread of diseases. Wild coffee species, notably those growing in seasonally highly arid environments in Madagascar, represent a critical genetic resource to address these challenges. Understanding adaptive traits allowing these species to establish into arid environments is essential to guide breeding strategies for creating resilient coffee varieties.AimsWe identified structural strategies likely to explain drought tolerance in wild Malagasy Coffea species.MethodsWe used architectural analysis to describe three Baracoffea species, C. ambongensis, C. bissetiae, and C. boinensis, and compare them to known cultivated. Structural and functional traits were measured across developmental stages.ResultsOur results suggest that, in addition to rhythmic growth and terminal flowering on shoots, Baracoffea species possess unique architectural characteristics including a complex architectural unit made of four different stem types, reflecting a high level of functional specialisation. Species-specific developmental strategies reflect different pathways into edifying plant architecture, mainly depending on primary and secondary growth trade-offs.ConclusionThese findings highlight the architectural diversity of Baracoffea, identify potentially important drivers of ecological adaptation through development pathways, and therefore highlight the potential of this group of species for breeding climate-resilient coffee varieties.
BackgroundUrban green and blue-green infrastructures (GI/BGI) support a wide range of ecosystem services, including flood mitigation, water and air quality improvements, biodiversity enhancement, and climate regulation. Vegetation is a central component of GI/BGI, yet effective implementation requires interdisciplinary knowledge exchange among scientists, planners, practitioners, policymakers, and the public.MethodsThis review explores the role of vegetation in the GI/BGI framework by synthesising foundational definitions, historical evolution of the concepts, and a range of ecosystem services provided by GI/BGI. It examines literature and case studies with a focus on biodiversity, plant dispersal, and the use of digital tools and mathematical models for ecosystem assessment.ResultsHydrology, vegetation and interconnectedness among components constitute three principal pillars for the GI/BGI concepts. GI/BGI systems contribute to aesthetic improvements, enhanced biodiversity, microclimate regulation, and protection of downstream waterbodies. Barriers such as policy fragmentation and underestimation of benefits are discussed, along with potential trade-offs and disbenefits. Brownfield sites emerged as important for urban biodiversity. The role of digital tools in modelling species dispersal and evaluating GI/BGI benefits is demonstrated through international case studies. The paper also provides an outline of a model representing the spread of biological species through the GI/BGI network and its potential application for assessment of biodiversity of plants, animals, fungi and algae in urban environments.ConclusionVegetation plays a critical role in GI/BGI and its successful implementation relies on interdisciplinary approaches, knowledge exchange and stakeholder collaboration. Further research should address knowledge gaps in biodiversity patterns and biogeochemical cycles, particularly through comparative ecosystem analysis and development of adaptive management strategies.
BackgroundRemarkably, half of the 10 plant hybrid species confirmed to have arisen naturally since 1500 arose within the British Isles (BI). The mechanisms included translocation of natural hybrids to a botanic garden, contact between native and a newly arrived species, and allopolyploidisation from a clonally spreading garden hybrid.AimsTo examine why the BI has so many described hybrid species.MethodsData on the recording of hybrids from the BI and nine other regions are examined in detail.ResultsFour factors played a part. First, Europe has more alien-to-native hybrids than elsewhere, probably due to large-scale habitat change plus phylogenetic proximity between aliens and natives. Second, the large number of botanists on the BI made the discovery of newly evolved hybrid species more likely. Third, the BI has many clonally spreading garden hybrids, which may generate hybrid neospecies. Finally, the eighteenth-century policies of Oxford Botanic Garden allowed the stabilisation of both S. squalidus and Platanus acerifolia, and hence eventually Senecio cambrensis and S. eboracensis.ConclusionInvestigations of these four factors will improve our understanding of the rate at which new species are forming in response to human activity across the world.
BackgroundThe role and relative importance of ecological processes (herbivory, fire) and human actions in shaping the pre-farming landscape of temperate north-west Europe is controversial, particularly in relation to processes that could have led to an open vegetation structure.AimsReconstruct the changing role of herbivory, fire, and human activity in shaping a landscape in north-west Europe.MethodsWe present a multi-proxy study from a sedimentary record at an archaeological site on the Meuse floodplain (Netherlands). We reconstruct local vegetation cover (phytoliths, macrofossils), regional vegetation cover (pollen), depositional and aquatic environment (sediment physical properties, diatoms and aquatic macrofossils), herbivory (non-pollen palynomorphs) and fire (charcoal).ResultsHigh herbivory and low fire activity characterised the pre-farming landscape. Regional-scale vegetation dynamics were stable, the vegetation being dominated by trees, but local vegetation fluctuated periodically between open and closed canopy. Cultivation commenced around 6500 years ago (elevated Cerealia-type pollen), and subsequently, fire activity increased (c. 6500 years ago), and herbivores disappeared (c. 5200 years ago).ConclusionsHerbivory in the pre-farming landscape maintained a dynamic mosaic of open vegetation within a forest matrix, which ceased when cultivation began. Our data show that humans have fundamentally changed the balance between herbivory and fire dynamics over thousands of years.
BackgroundThe recent colonisation of Carex salina in Scotland presents an opportunity to compare population genetic structure with long-established Norwegian populations. The closely related long-established Scottish C. recta allowed removal of the potentially confounding effects of latitude.AimsTo compare genetic diversity, balance between clonal and sexual reproduction, clonal architecture in new and long-established populations of C. salina and C. recta, respectively.MethodsSimple sequence repeat markers were used to quantify genetic parameters within all extant populations of C. recta and C. salina in Scotland and in C. salina sampled across its latitudinal range in Norway.ResultsScottish and Norwegian populations of C. salina, and Scottish C. recta showed similar levels of expected heterozygosity. Almost all populations showed heterozygote excess. Clonality was lowest in Scottish C. salina. The few Scottish C. salina clones were large with very little overlap. By comparison, Norwegian C. salina and Scottish C. recta had smaller, overlapping clones.ConclusionScottish saltmarshes have been colonised by C. salina on multiple occasions with insufficient time for extensive clonal growth to occur. It will be instructive to undertake future examination of the genetic structure of these Scottish populations to assess how they change over time.
BackgroundHybridisation plays a key role in plant evolution. The extent to which parental divergence can predict the outcome of hybridisation (e.g. the ability to form hybrids and hybrid fertility) has most often been studied using a small number of individuals and/or DNA barcodes which could result in erroneous measures of parental divergence.AimsThis study investigated the relationship between genetic divergence and the formation and fertility of hybrids, using Epilobium sect. Epilobium (willowherbs) of the British Isles as a model.MethodsWe used reduced representation sequencing to generate a phylogeny of Epilobium, which vary in their propensity to hybridise. Genetic distance was compared to the occurrence and seed set of hybrids using the literature available on this genus.ResultsA phylogeny constructed from 3522 quality-filtered SNPs from 44 samples of 10 species and four putative hybrid individuals, resolved all but one species as monophyletic. Two hybrid individuals were confirmed, and one additional hybrid was identified. All were likely to be F1 hybrids.ConclusionWe did not detect a significant relationship between parental divergence and hybridisation likelihood and/or hybrid fertility in Epilobium sect. Epilobium, contradicting the hypothesis that increasing genetic divergence decreases hybrid formation and hybrid fertility.
