Effect of Nitrogen Application Rate on the Relationships between Multidimensional Plant Diversity and Ecosystem Production in a Temperate Steppe.

Forest biodiversity world‐wide is affected by climate change, habitat loss and fragmentation, and today 20% of the forest area is located within 100 m of a forest edge. Still, forest edges harbour a substantial amount of terrestrial biodiversity, especially in the understorey. The functional and phylogenetic diversity of forest edges have never been studied simultaneously at a continental scale, in spite of their importance for the forests' functioning and for communities' resilience to future change. We assessed nine metrics of taxonomic, phylogenetic and functional diversity of understorey plant communities in 225 plots spread along edge‐to‐interior gradients in deciduous forests across Europe. We then derived the relative effects and importance of edaphic, stand and landscape conditions on the diversity metrics. Here, we show that taxonomic, phylogenetic and functional diversity metrics respond differently to environmental conditions. We report an increase in functional diversity in plots with stronger microclimatic buffering, in spite of their lower taxonomic species richness. Additionally, we found increased taxonomic species richness at the forest edge, but in forests with intermediate and high openness, these communities had decreased phylogenetic diversity. Functional and phylogenetic diversity revealed complementary and important insights in community assembly mechanisms. Several environmental filters were identified as potential drivers of the patterns, such as a colder macroclimate and less buffered microclimate for functional diversity. For phylogenetic diversity, edaphic conditions were more important. Interestingly, plots with lower soil pH had decreased taxonomic species richness, but led to increased phylogenetic diversity, challenging the phylogenetic niche conservatism concept. Synthesis . Taxonomic, phylogenetic and functional diversity of understorey communities in forest edges respond differently to environmental conditions, providing insight into different community assembly mechanisms and their interactions. Therefore, it is important to look beyond species richness with phylogenetic and functional diversity approaches when focusing on forest understorey biodiversity.

Abstract:Several studies have evaluated the short-term effects of tropical forest fragmentation on plant taxonomic diversity, while only a few have evaluated its effects on functional or phylogenetic diversity. To our knowledge no study has looked at the long-term consequences of tropical forest fragmentation on the three main components of plant diversity simultaneously: taxonomic, functional and phylogenetic diversity. We sampled the vascular flora using belt transects (50 × 4 m) in a continuous tropical semi-evergreen forest (16 transects) and in an adjacent naturally fragmented forest (fragments of 1.7-My-old semi-evergreen forest immersed in a mangrove/sedge matrix) (18 transects), and compared their taxonomic, functional and phylogenetic plant diversity. There were 36 species in the continuous forest and 28 in the fragmented forest. Continuous forest was taxonomically more diverse (25%) than the fragmented forest. All functional diversity metrics were greater (6–33%) in the continuous than in the fragmented forest. Phylogenetic diversity was 19% greater and phylogenetically more overdispersed in the continuous forest than in the fragmented forest. The results suggest that in the fragmented forest not only is taxonomic plant diversity lower, but functional and phylogenetic diversity are as well. The negative effects of forest fragmentation on plant diversity seem to be chronic.

We investigate the ecological and evolutionary variables that best explain spatial diversity patterns of anuran amphibians in three of South America's most diverse and geographically widespread biomes: the Cerrado, Amazonia, and Atlantic Rainforest. We used Conditional Autoregressive Models to assess the potential influence of present-day climate (temperature and precipitation), historical climate (stability over the last 120,000 years), potential evapotranspiration (PET), and topography (slope, aspect, and rugosity) on spatial variation in taxonomic, functional, and phylogenetic diversity at a resolution of 0.5 × 0.5 degrees. Both taxonomic diversity and phylogenetic diversity increased with long-term climatic stability in all regions. By contrast, functional diversity was negatively impacted by precipitation in the driest quarter. However, the relative importance of each predictor variable differed among diversity metrics and biomes. In the Atlantic Rainforest, potential evapotranspiration was positively correlated with functional diversity but negatively associated with taxonomic and phylogenetic diversity. In Amazonia, precipitation and relief slopes were positively associated with functional and phylogenetic diversity, respectively, whereas relief slopes were negatively correlated with taxonomic diversity. In the Cerrado, precipitation was negatively correlated with functional diversity, but climatic stability was more strongly associated with phylogenetic and taxonomic diversity. These findings indicate that present-day climatic factors are critical in forested biomes, whereas a combination of historical and current variables is more relevant in Cerrado's savanna mosaics. Notably, ecotones exhibit significantly higher functional diversity (except for Amazon), reflecting the encounter of faunas from adjacent biomes having distinct ecological regimes and thus associated organismal traits. Characterizing the drivers of heterogeneous biodiversity distribution will offer insights into the assembly of ecological communities in other tropical and transitional ecosystems and can potentially guide conservation strategies globally.

Multiple measures of plant diversity are vital to understand the response of plant communities to changing environmental conditions in peatlands. We assessed whether functional, phylogenetic and taxonomic diversities of woody and herbaceous fen peatlands in East Anglia, UK varied between plant communities under different management practices (mowing and grazing). We adjusted the weight of phylogenetic distances in a combined functional-phylogenetic distance matrix to assess functional and phylogenetic diversities separately and in combination. We tested the phylogenetic signal of four traits (leaf dry-matter content, leaf N, leaf δ13C and leaf δ15N) and employed null models to determine patterns of clustering and over-dispersion of traits and phylogenies. We used rarefaction to determine if observed taxonomic diversity was higher or lower than expected. Functional, phylogenetic and taxonomic diversities varied across and within vegetation types. Annual grazing was associated with reduced functional and phylogenetic diversities but was not significantly associated with taxonomic diversity. Annual mowing was associated with increased phylogenetic and taxonomic diversities. Multiple diversity metrics can provide complementary or contrasting information. While there are benefits to annual management of wetlands (benefitting rare species), these must be weighed against eroding functional and phylogenetic diversities that can potentially adversely affect responses to environmental change. Communities mown every seven to eight years supported characteristic fen vegetation and maintained high plant diversity across a range of measures. Our results sound a cautionary note of neglecting to monitor multiple plant diversity measures in managed habitats, since attempts to maximize one may inadvertently lead to the erosion of others.

Habitat fragmentation is considered as major threat to biodiversity worldwide. Biodiversity can be described as taxonomic, functional and phylogenetic diversity. However, the effect of forest fragmentation on taxonomic, phylogenetic and functional diversity is barely understood. We compare the response of taxonomic (species richness), phylogenetic and functional diversity of birds to forest fragmentation. We hypothesised that with increasing forest patch isolation and/or decreasing patch size the diversity of birds decreases but only if certain thresholds of fragmentation metrics are reached. Specifically, we hypothesized that out of the three diversity components the taxonomic diversity is the most sensitive to forest fragmentation, which means that it starts declining at larger patch size and higher connectivity values than phylogenetic and functional diversity do. We compared the three biodiversity metrics of central European bird species in a large set of forest patches located in an agricultural landscape. General additive modeling and segmented regression were used in analyses. Habitat fragmentation differentially affected studied biodiversity metrics. Bird taxonomic diversity was the most responsive towards changes in fragmentation. We observed an increase in taxonomic diversity with increasing patch area, which then stabilized after reaching certain patch size. Functional diversity turned out to be the least responsive to the fragmentation metrics and forest stand characteristics. It decreased linearly with the decreasing isolation of forest patches. Apart from the habitat fragmentation, bird taxonomic diversity but not phylogenetic diversity was positively associated with forest stand age. The lower share of dominant tree species, the highest taxonomic diversity was. While preserving a whole spectrum of forests (in terms of age, fragmentation and size) is important from the biodiversity perspective, forest bird species might need large, intact, old-growth forests. Since the large and intact forest becomes scarcer, our study underscore their importance for the preservation of forest specialist species.

Although species richness has been hypothesized to be highest at 'intermediate' levels of disturbance, empirical studies have demonstrated that the disturbance-diversity relationship can be either negative or positive depending on productivity On the other hand, hypothesized productivity diversity relationships can be positive, negative or unimodal, as confirmed by empirical studies. However, it has remained unclear under what conditions each pattern is realized, and there is little agreement about the mechanisms that generate these diverse patterns. In this study, I present a model that synthesizes these separately developed hypotheses and shows that the interactive effects of disturbance and productivity on the competitive outcome of multispecies dynamics can result in these diverse relationships of species richness to disturbance and productivity The predicted productivity diversity relationship is unimodal but the productivity level that maximizes species richness increases with increasing disturbance. Similarly, the predicted disturbance diversity relationship is unimodal but the peak moves to higher disturbance levels with increasing productivity Further, these patterns are well explained by the opposite effects of productivity and disturbance on competitive outcome that are suggested by the change in community composition along these two environmental gradients: higher productivity favours superior competitors while higher disturbance levels favour inferior competitors.

Soil respiration (Rs) is a key ecosystem function that controls the terrestrial energy balance and element cycling. Quantifying how plant diversity affects Rs is critical for predicting the impact of global plant diversity loss on ecosystem function. However, it is unclear how soil factors and plant diversity are spatially interrelated under natural environmental gradients, and how plant diversity affects the spatial variation of Rs on the basis of soil factors. Our objectives were to quantify the direction and magnitude of direct and indirect effects of plant diversity on Rs. We assessed spatial variability in the relationships between soil factors (soil chemistry and microclimate), multiple dimensions of plant diversity (taxonomic, functional, and phylogenetic diversity), and Rs using a new combination of geographically weighted regression and structural equation modeling based on survey data from three plots (river bank, transitional zone, and desert margin plots) along an environmental gradient in northwest China. Reduced plant diversity had a negative impact on Rs. However, when the effects of soil factors on Rs and spatial non-stationarity were considered simultaneously, the relationship between plant diversity and Rs changed in magnitude and direction. From the river bank to the desert margin, the positive effect of taxonomic and functional diversity on Rs gradually weakened, while the effect of phylogenetic diversity on Rs changed from a negative to a positive effect. Plant diversity and soil factors together explained 55%–75% of the spatial variation in Rs. Among them, the contribution of plant diversity to the spatial variation of Rs gradually decreased from the river bank to the desert margin, while the contribution of soil factors gradually increased. Functional diversity (17.39%–18.93%) and phylogenetic diversity (10.75%–19.53%) better explained the spatial variability of Rs compared with taxonomic diversity (2.67%–6.01%). The results provide strong evidence that plant diversity, especially functional and phylogenetic diversity, is a key driver of Rs, expanding our understanding of the relationship between plant diversity and Rs. These findings more accurately reveal the changing characteristics of carbon dynamics in desert ecosystems, and provide a methodological framework for studying the spatial variability of the relationship between plant diversity and ecosystem function.

AimRaptors, a highly threatened but ecologically important group of birds, have been recognized as a good proxy for overall biodiversity in conservation planning. However, previous work on raptor diversity focused predominantly on taxonomic diversity. Here, we assess the global patterns of raptor taxonomic, phylogenetic and functional diversity and their association with current and historical environmental factors.LocationGlobal.Time periodPresent day.Major taxa studiedRaptors.MethodsWe compiled information from distribution maps, global trait datasets and avian phylogenies for all extant raptors. We used generalized least squares (GLS) to assess the relationship between historical and contemporary environmental predictors and species richness, phylogenetic diversity [Faith's phylogenetic diversity index (Faith's PD), mean pairwise distance (MPD) and mean nearest taxon distance (MNTD)] and functional diversity of traits related to raptor morphology, lifestyles, diet, foraging and vagility, while controlling for spatial autocorrelation.ResultsRaptor taxonomic diversity peaked in tropical regions and nearby mountain ranges. After controlling for species richness, species‐poor assemblages in high latitudes and deserts were more phylogenetically and functionally diverse than expected by chance. In species‐rich assemblages, diet and foraging traits had greater variation, whereas morphological traits had less variation than expected, suggesting that species packing promoted adaptive radiation in these assemblages. Historical climate influenced phylogenetic diversity and functional diversity of morphological, foraging and diet traits, leaving a signal of evolutionary history on modern assemblages. Human footprint was also an important driver of MPD and of niche and vagility trait functional diversity, with higher phylogenetic diversity in disturbed areas and with higher functional diversity in regions with intermediate levels of disturbance.Main conclusionsBoth palaeoclimate and contemporary environmental conditions are important drivers of raptor phylogenetic and functional diversity. We found large mismatches among taxonomic, functional and phylogenetic diversity, demonstrating how different processes filter lineages and species traits shaping raptor assemblages. Our results highlight the need to consider multiple dimensions of diversity to inform conservation planning better when using raptors as umbrella species.

Climate change and anthropogenic alteration of landscapes negatively impact the abundance and species diversity of plant and animal communities worldwide. Much less is known about the effects on phylogenetic diversity and community functioning. Here we use long‐term butterfly data (1980–2022) from the Austrian Alps along an elevation gradient. We assessed how communities adjust structures and functionality to increasing temperatures, and how these changes are linked to trait expression and community functioning. Species diversity decreased at low and intermediate altitudes, and increased at high ones. Functional diversity was lower than expected by a random model at intermediate and high altitudes and increased with time at high, but not at intermediate and low altitudes. Phylogenetic diversity did not show significant temporal trends at low altitude, but increased with time at intermediate and high altitudes. Multifunctionality significantly decreased at intermediate and high altitudes and was not significantly correlated with functional diversity, but was negatively correlated with phylogenetic diversity. We argue that the ongoing homogenisation of Alpine butterfly communities strongly affects species, functional and phylogenetic diversity. The assessment of species richness and diversity alone, as provided by common species surveys, might give a false impression about the state and functional diversity of Alpine insect communities in the course of climate change. The directions of faunal changes heavily depend on altitude and therefore on specific climatic conditions. Higher altitudes face decreasing butterfly multifunctionality despite of increasing species richness due to climate induced altitudinal up‐hill shifts of many species. We conclude that studies on community time series should include phylogenetic and functional diversity besides of being focused on richness and endangerment. Red lists might be extended by categories on functional importance and phylogenetic distinctness.

Biocrusts are major contributors to dryland diversity, functioning, and services. However, little is known about how habitat degradation will impact multiple facets of biocrust diversity and measurable functional traits. We evaluated changes in taxonomic, functional, and phylogenetic diversity of biocrust-forming lichens along a habitat degradation gradient related to the presence of linear infrastructure (i.e., a road) and a profound agricultural driven transformation. To do so, we selected 50 remnants of a Mediterranean shrubland. We considered several surrogates of habitat quality and causal disturbance on the various diversity facets of biocrusts by using structural equation modeling, hypothesizing that habitat degradation primarily affects functional diversity, which in turn regulates changes in taxonomic and phylogenetic diversities, and also that taxonomic and phylogenetic diversities are coupled. Fragment connectivity, distance to linear infrastructure (i.e., a road) and, particularly, soil fertility (i.e., soil P concentration), had mostly negative effects on biocrust functional diversity, which in turn affected both taxonomic and phylogenetic diversities. However, we found no direct effects of habitat degradation variables on the taxonomic and phylogenetic diversities. We also found that increases in phylogenetic diversity had a positive effect on taxonomic diversity along the habitat degradation gradient. Our results indicate that functional diversity of biocrusts is strongly affected by habitat degradation, which may profoundly alter their contribution to ecosystem functioning and services. Furthermore, functional diversity regulates the response of biocrust taxonomic and phylogenetic diversity to habitat degradation. These findings indicate that habitat degradation alters and simplifies the diversity of functional traits of biocrust-forming lichens, leading to biodiversity loss, with important consequences for the conservation of global drylands biodiversity.

Context The increase in surface dominated by woody species and the consequent reduction of grassland areas is globally reported phenomenon. This ecological process, known as woody plant encroachment (WPE), is a major driver of landscape change, reshaping spatial patterns and ecological functioning. WPE has been shown to affect various ecosystem variables, including plant diversity. Although taxonomic diversity (TD) has been the focus of most studies, often with inconsistent findings, much less is known about how functional and phylogenetic dimensions of diversity respond to this process. Objectives This study addressed four main objectives: (i) to analyse changes in phylogenetic plant diversity along the WPE gradient; (ii) to explore the relationship between different facets of diversity; (iii) to analyse the degree of decoupling between phylogenetic diversity (PD) and functional diversity (FD) at different levels of encroachment; and (iv) to characterise the patterns of diversity components in relation to woody cover. Methods The research was conducted at four sites in the north of the Iberian Peninsula, where plots were established along a gradient of woody plant cover. Four WPE levels were considered, with a total of 36 replicate plots per level across the study area. In each plot, several indices were calculated to quantify TD, FD, and PD. Results Phylogenetic plant diversity showed a gradual increase with higher cover of encroaching shrubs. Phylogenetic overdispersion was observed in shrubland communities, mainly due to the presence of older lineages such as pteridophytes and gymnosperms. When the analysis was restricted to angiosperms, phylogenetic clustering appeared at lower levels of woody cover, indicating a stronger influence of environmental filters. Regarding the relationships among diversity dimensions, a negative relationship was observed between TD and the other components, FD and PD, highlighting ecological redundancy. In contrast, FD and PD maintained a positive relationship, reflecting trait conservatism across lineages, although this relationship weakened when only angiosperms were considered. The direction of PD–FD decoupling varied depending on the level of woody encroachment and the taxonomic scope analysed: shrubland communities exhibited PD-driven decoupling, likely linked to the influence of non-angiosperm lineages, whereas grassland communities showed FD-driven decoupling, reflecting adaptive divergence among closely related taxa. Both functional and phylogenetic diversity tended to increase along the gradient of encroaching species cover, whereas taxonomic diversity peaked at intermediate covers (5–30%) before declining under higher shrub cover. Conclusions The findings of this study highlight that the different facets of plant diversity do not respond uniformly to increasing shrub encroachment. This reinforces the need for a multifaceted approach to better understand the complexity of the shrub encroachment process.

BackgroundThe geographic patterns of plant diversity in the Qinghai-Tibet Plateau (QTP) have been widely studied, but few studies have focused on wetland plants. This study quantified the geographic patterns of wetland plant diversity in the QTP through a comprehensive analysis of taxonomic, phylogenetic and functional indices.MethodsBased on a large number of floras, monographs, specimens and field survey data, we constructed a comprehensive dataset of 1,958 wetland plant species in the QTP. Species richness (SR), phylogenetic diversity (PD), functional diversity (FD), net relatedness index (NRI) and net functional relatedness index (NFRI) were used to assess the taxonomic, phylogenetic and functional diversity of wetland plants. We explored the relationships between the diversity indices and four categories of environmental variables (i.e. energy-water, climate seasonality, topography and human activities). We used four diversity indices, namely endemic species richness, weighted endemism, phylogenetic endemism and functional endemism, together with the categorical analysis of neo- and paleo-endemism (CANAPE), to identify the endemic centers of wetland plants in the QTP.ResultsSR, PD and FD were highly consistent and showed a decreasing trend from southeast to northwest, decreasing with increasing elevation. The phylogenetic structure of wetland plant assemblages in most parts of the plateau is mainly clustered. The functional structure of wetland plant assemblages in the southeast of the plateau is overdispersed, while the functional structure of wetland plant assemblages in other areas is clustered. Energy-water and climate seasonality were the two most important categories of variables affecting wetland plant diversity. Environmental variables had a greater effect on the functional structure of wetland plants than on the phylogenetic structure. This study identified seven endemic centres, mainly in the Himalayas and Hengduan Mountains.ConclusionsClimate and topography are the main factors determining the geographic distribution of wetland plant diversity at large scales. The majority of grid cells in the QTP with significant phylogenetic endemism were mixed and super-endemism. At large scales, compared to climate and topography, human activities may not have a negative impact on wetland plant diversity in the QTP.

Multidimensional biodiversity approaches provide a framework for understanding the ecological and evolutionary processes that shape communities through time and space. In this study, we assess the spatial variation in taxonomic, phylogenetic, and functional diversity of reptile assemblages along Chile’s latitudinal gradient to gain insight into the primary assembly processes structuring these communities. We compiled data on distribution, phylogeny, and functional traits and estimated alpha diversity indices of taxonomic, phylogenetic, and functional dimensions. We then assessed the assembly process under the stress dominance hypothesis (SDH), using null models to test whether the observed phylogenetic and functional diversity deviated from random patterns, suggesting the influence of habitat filtering or interspecific competition. We also examined environmental influences on diversity metrics. Our results show that phylogenetic diversity is a poor proxy for functional diversity, highlighting the importance of multidimensional approaches to understanding the drivers of assemblage composition and structure. In support of the SDH, habitat filtering influenced reptile assemblages in arid and cold environments, whereas interspecific competition influenced the assemblages in milder environments, such as the Mediterranean region and Valdivian forests. Furthermore, the spatial mismatch between diversity metrics allowed us to explore how assemblage composition and structure are influenced by local environmental heterogeneity, biogeographic history, and adaptive radiations of squamate reptiles. Environmental variables, particularly temperature, primary productivity, and topographic complexity, emerged as strong predictors of reptile diversity. Our study highlights the importance of integrating species’ evolutionary history and ecological traits with taxonomic richness to improve our understanding of community composition, ecosystem functioning, history, and resilience.

Summary Theory predicts that the processes generating biodiversity after disturbance will change during succession. Comparisons of phylogenetic and functional (alpha and beta) diversity with taxonomic diversity can provide insights into the extent to which community assembly is driven by deterministic or stochastic processes, but comparative approaches have yet to be applied to successional systems. We characterized taxonomic, phylogenetic and functional plant (alpha and beta) diversity within and between four successional stages in a > 270‐year‐long arable‐to‐grassland chronosequence. Null models were used to test whether functional and phylogenetic turnover differed from random expectations, given the levels of species diversity. The three facets of diversity showed different patterns of change during succession. Between early and early‐mid succession, species richness increased but there was no increase in functional or phylogenetic diversity. Higher than predicted levels of functional similarity between species within the early and early‐mid successional stages, indicate that abiotic filters have selected for sets of functionally similar species within sites. Between late‐mid and late succession, there was no further increase in species richness, but a significant increase in functional alpha diversity, suggesting that functionally redundant species were replaced by functionally more dissimilar species. Functional turnover between stages was higher than predicted, and higher than within‐stage turnover, indicating that different assembly processes act at different successional stages. Synthesis. Analysis of spatial and temporal turnover in different facets of diversity suggests that deterministic processes generate biodiversity during post‐disturbance ecosystem development and that the relative importance of assembly processes has changed over time. Trait‐mediated abiotic filtering appears to play an important role in community assembly during the early and early‐mid stages of arable‐to‐grassland succession, whereas the relative importance of competitive exclusion appears to have increased towards the later successional stages. Phylogenetic diversity provided a poor reflection of functional diversity and did not contribute to inferences about underlying assembly processes. Functionally deterministic assembly suggests that it may be possible to predict future post‐disturbance changes in biodiversity, and associated ecosystem attributes, on the basis of species’ functional traits but not phylogeny.

Biodiversity can be quantified by taxonomic, phylogenetic, and functional diversity. Current evidence points to a lack of congruence between the spatial distribution of these facets due to evolutionary and ecological constraints. A lack of congruence is especially evident between phylogenetic and taxonomic diversity since the name and number of species are an artificial, yet commonly used, way to measure biodiversity. Here we hypothesize that due to evolutionary constraints that link phylogenetic and functional diversity, areas with higher phylogenetic and functional diversity will be spatially congruent in Neotropical cocosoid palms, but neither will be congruent with areas of high taxonomic diversity. Also, we hypothesize that any congruent pattern differs between rainforests and seasonally dry forests, since these palms recently colonized and diversified in seasonally dry ecosystems. We use ecological niche modeling, a phylogenetic tree and a trait database to test the spatial congruence of the three facets of biodiversity. Taxonomic and phylogenetic diversity were negatively correlated. Phylogenetic and functional diversity were positively correlated, even though their spatial congruence was lower than expected at random. Taken together, our results suggest that studies focusing solely on large-scale patterns of taxonomic diversity are missing a wealth of information on diversification potential and ecosystem functioning.