Inselbergs, isolated rock outcrops, support unique plant communities. Maritime inselbergs (MIs) experience transient isolation due to maritime fluctuations, creating harsh survival conditions. This study is the first to investigate the plant communities' patterns on MIs, comparing them with those on continental inselbergs (CIs). We explore how oceanic filtering and climatic factors shape species and phylogenetic diversity, the threatened statuses of the species, and the impact of extinction scenarios on phylogenetic diversity and structure.
MIs and CIs in the Atlantic Forest of Southeast Brazil.
We analyzed species and phylogenetic patterns across 15 inselbergs (nine CIs and six MIs), including new data from Alcatrazes Island. Floristic dissimilarities were assessed using ward's clustering, and species and phylogenetic relationships were explored through NMDS ordination and phylogenetic PCA. Oceanic filtering and climatic factors were evaluated using convex hulls and bioclimatic variable fits. Phylogenetic diversity (PD) and structure, measured as mean pairwise distance (MPD), were assessed, along with species threat status based on the Brazilian Red List. Simulated extinction scenarios, randomly removing 5%–90% of species, were modeled to evaluate effects on phylogenetic metrics.
MI species and phylogenetic composition differed significantly from CIs, influenced by oceanic isolation, isothermally, and precipitation seasonality. We found no significant difference in PD between CIs and MIs. Only 11% of the 753 species were shared, with 10% classified as threatened. PD decreased with increasing extinction rates (p < 0.01, R2 > 0.7) across all communities. MIs exhibited clustered phylogenetic structures, while CIs showed random structures. Random extinction sharply reduced PD, and phylogenetic structures were disrupted in all communities at 25% extinction.
We introduce the concept of MIs, demonstrating that their flora differs significantly from CIs due to oceanic isolation and climatic factors. Although historically connected, geomorphological conditions, subsequent isolation, and environmental filtering by the sea have led to a unique maritime species and phylogenetic composition. Extinction sce
The detection and interpretation of ecological processes are strongly influenced by the spatial scale at which studies are conducted. Scale terms (e.g., ‘local’ or ‘regional’) are frequently used to denote study scale and imply that studies using the same scale term should be directly comparable. However, whether the area encompassed by a particular scale term is consistent across studies remains unclear.
Global.
We reviewed 385 papers in plant community ecology and analysed 962 spatial scale terms and their reported areas. We tested whether variation in the use of individual scale terms could be explained by habitat, type of study or geographic region, and virtually sampled a simulated plant community to demonstrate the consequences of this variation for calculating common biodiversity metrics.
Single scale terms covered areas that vary by an average of 4.7 orders of magnitude, with significant overlap between distinct scale terms. Though this variation could be partly explained by habitat type (e.g., scale terms cover larger areas in forests than grasslands), we still found large variability (3.8 orders of magnitude) in the use of single terms within habitats. We also found overall high consistency (but still high variability) in the use of scale terms across geographic regions and study types. Our community simulation showed that Shannon's and Simpson's indices are highly sensitive to this variation, especially at finer spatial scales, suggesting that variation in the use of individual scale terms has major consequences for synthesising biodiversity trends.
While terminology can make it appear that studies are directly comparable, they may cover vastly different areas and capture different ecological processes. Spatial scales should be reported in a standardised fashion by clearly stating the actual study size in abstracts and methods, and inconsistencies in scale term use should be accounted for when synthesising previous research.
Understanding ecosystem resilience to environmental change requires evaluating how novel disturbances affect biological legacies that influence regeneration. Legacies that help maintain conditions for recovery may be lost if disturbance regimes change and species lack the necessary adaptive responses. This study assesses the short- and longer-term impacts of fire in Caribbean tropical dry forests with limited burn history to determine their resilience and identify functional traits predicting postfire resprouting strategies.
The study was conducted in tropical dry forests of SW Puerto Rico along a 29-year postfire chronosequence.
We examined community-level measures of structure, composition, diversity, and resprouting of woody plants in sites ranging from 2 months to 29 years postfire, comparing them to mature forests. Additionally, we tested whether functional traits—relative bark thickness, specific leaf area, and tree size—could predict postfire resprouting strategies.
Tropical dry forest sites with limited burn history exhibited little structural resistance to fire, though significant basal resprouting was observed among tree communities. Over the long term, the chronosequence did not show recovery trends in structural, compositional, or diversity metrics toward mature forest conditions. Fire negatively impacted biological legacies important to forest regeneration, including reducing canopy density, enhancing abiotic stressors, and creating conditions conducive to exotic grass invasion and recurring fire. Functional traits such as relative bark thickness, specific leaf area, and stem number were key predictors of resprouting strategies, highlighting diverse regeneration responses among Caribbean tropical dry forest species.
Puerto Rican tropical dry forest is not resilient to fire, as it disrupts biological legacies critical for regeneration and promotes transitions to degraded states that are difficult to restore. While resprouting remains a postfire legacy, fire alters ecosystem dynamics in ways that challenge long-term recovery. A conceptual model is proposed to illustrate how fire disrupts regeneration processes in Caribbean tropical dry forest.
Most of our current knowledge on tropical forest plant communities is based on trees, despite the substantial contribution of other lifeforms to plant diversity in these systems. In particular, there is a limited number of studies on understory herbaceous plants (herbs) in tropical forests. With their lower dispersal abilities, higher rates of evolution, and lower drought tolerance than trees, herbs are expected to exhibit different patterns of species composition across space. To compare the patterns and drivers of variation in species composition (β-diversity) between these two plant groups, we surveyed tree and herb communities in 13 one-ha plots along a rainfall gradient in a seasonally dry forest in India.
Mudumalai National Park, India.
In each one-ha plot, we censused all trees ≥ 1 cm DBH in each one-ha plot, and herbs in 47–50 1 × 1 m subplots within each one-ha plot. In both groups, we estimated among-plot β-diversity, which we decomposed into two components: turnover and nestedness. Then we partitioned the relative influences of spatial and environmental predictors, including rainfall, temperature, soil, and fire frequency, on β-diversity.
Contrary to our expectations, β-diversity was remarkably similar for herbs and trees, and both groups exhibited high turnover along the gradient. Rainfall and temperature explained most variation in composition within both groups, while fire and soil explained less variation, and their effects differed between groups.
While trees and herbs show contrasting patterns of α-diversity across the same rainfall gradient, our study suggests that both life forms are impacted strongly by environmental filtering, predominantly rainfall and temperature, resulting in similar patterns of β-diversity. The high turnover observed in tree and herb communities, and the influence of rainfall and temperature in structuring these communities, should be considered when designing conservation and restoration strategies in the face of ongoing global change and other anthropogenic pressures on tropical forests.
Community resistance to non-native plant invasions results from intrinsic habitat characteristics, propagule pressure, and the presence of disturbance. Species identity further complicates this relationship due to pre-existing adaptations. Despite these mechanisms being understood in isolation, their interplay is rarely explored in natural field communities. Furthermore, while survey studies have reported levels of invasion across habitat types, few have quantified differences in intrinsic invasibility experimentally.
Roy Berg Kinsella Research Ranch, Alberta, Canada.
We manipulated soil disturbance and propagule pressure in three habitat types (aspen forest, shrub vegetation, and prairie grassland) and examined their impact on the germination success of three pairs of phylogenetically similar native and non-native plant species (Bromus ciliatus/B. inermis, Elymus trachycaulus/Agropyron cristatum, Poa secunda/P. pratensis) for 3 months after seed addition.
Habitats played a crucial role in determining resistance to invasion, with aspen forest exhibiting the highest germination rates and invasibility and prairie grassland the lowest. High propagule pressure significantly increased invasibility across all habitat types and genera, and its impact was most pronounced when combined with soil disturbance, though this was contingent on genus. Invasive Bromus had higher germination compared to its native congener, even in the absence of disturbance. However, native Elymus and Poa species had equal or greater germination compared to their non-native counterparts.
Our results underline that propagule pressure, disturbance, and species identity interact as drivers of plant community invasibility. Furthermore, our study demonstrated that habitat types differ in their intrinsic resistance to invasions. While aspen forests have greater invasibility, grasslands are more invaded than their resistance suggests. Thus, invasibility contrasts with levels of invasion reported in field surveys, supporting previous suggestions that these attributes do not always align.
Zeidler M., Šipoš J., Banaš M., Václavík T. (2025): Response of Subalpine Plant Vegetation to Snow Cover Duration Quantified by In Situ Repeat Photography. Journal of Vegetation Science, 36:e70016. https://doi.org/10.1111/jvs.70016
The title “Response of subalpine plant vegetation to snow cover duration quantified by in situ repeat photography” includes a redundancy (“plant vegetation”).
Please, correct the title to “Response of subalpine vegetation to snow cover duration quantified by in situ repeat photography.”
We apologize for this error.
Zeidler M., Šipoš J., Banaš M., Václavík T.
The community composition of native and alien plant species is influenced by the environment (e.g., nutrient addition and changes in temperature or precipitation). A key objective of our study is to understand how differences in the traits of alien and native species vary across diverse environmental conditions. For example, the study examines how changes in nutrient availability affect community composition and functional traits, such as specific leaf area and plant height. Additionally, it seeks to assess the vulnerability of high-nutrient environments, such as grasslands, to alien species colonization and the potential for alien species to surpass natives in abundance. Finally, the study explores how climatic factors, including temperature and precipitation, modulate the relationship between traits and environmental conditions, shaping species success.
In our study, we used data from a globally distributed experiment manipulating nutrient supplies in grasslands worldwide (NutNet).
We investigate how temporal shifts in the abundance of native and alien species are influenced by species-specific functional traits, including specific leaf area (SLA) and leaf nutrient concentrations, as well as by environmental conditions such as climate and nutrient treatments, across 17 study sites. Mixed-effects models were used to assess these relationships.
Alien and native species increasing in their abundance did not differ in their leaf traits. We found significantly lower specific leaf area (SLA) with an increase in mean annual temperature and lower leaf Potassium with mean annual precipitation. For trait–environment relationships, when compared to native species, successful aliens exhibited an increase in leaf Phosphorus and a decrease in leaf Potassium with an increase in mean annual precipitation. Finally, aliens' SLA decreased in plots with higher mean annual temperatures.
Therefore, studying the relationship between environment and functional traits may portray grasslands' dynamics better than focusing exclusively on traits of successful species, per se.
Spatial patterns of plant traits have rarely been studied at distances below 10 cm. Is it possible to detect nonrandom functional patterns at a very fine scale in mountain secondary grasslands? An analysis in terms of trait similarity, magnitude and density correlation can highlight the importance of different biotic and abiotic processes at these scales. We expect species identity to be of secondary importance if all individuals are identified by their measured traits, resulting in consistent patterns whether it is considered or not, especially if ITV (intraspecific trait variability) and functional overlap are high.
Natural reserve “Montagna di Torricchio,” a strict reserve in the Marche region, central Apennines, Italy.
Plant height, leaf area, and specific leaf area have been measured for each individual (1094 ramets) in 10 quadrats, divided into two grasslands differing in canopy cover. Functional redundancy and ITV were evaluated with overlap measures and variance partitioning. Marked point pattern statistics have been used to test for non-randomness of trait patterns either by considering all individuals at once or by excluding conspecific pairs.
At distances below 8 cm, we found evidence of trait convergence, pairs smaller than expected and negative density correlation. Above 8 cm, we found trait divergence and larger than expected pairs. We suggest biotic and abiotic causes for this, linked to physical packing or similarity in soil depth, respectively. The results differed between traits and between grasslands. The results were consistent whether conspecific pairs were excluded or not. There is a high functional overlap among species, and ITV has a large contribution to variability.
We found nonrandom functional patterns in grasslands below 10 cm, an almost unexplored scale range in any vegetation. The approach used showed that taxonomic identity is less important than the functional setting of individuals at this scale.
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