Different Dimensions Of Biodiversity Research Articles

Pelagic zone is an evolutionary catalyst, but an ecological dead end, for North American minnows.

Colonization of a novel geographic area is a classic source of ecological opportunity. Likewise, complex microhabitats are thought to promote biodiversity. We sought to reconcile these two predictions when they are naturally opposing outcomes. We assess the macroevolutionary consequences of an ancestral shift from benthic to pelagic microhabitat zones on rates of speciation and phenotypic evolution in North American minnows. Pelagic species have more similar phenotypes and slower rates of phenotypic evolution, but faster speciation rates, than benthic species. These are likely two independent, opposing responses to specialization along the benthic-pelagic axis, as rates of phenotypic evolution and speciation are not directly correlated. The pelagic zone is more structurally homogenous and offers less ecological opportunity, acting as an ecological dead end for minnows. In contrast, pelagic species may be more mobile and prone to dispersal and subsequent geographic isolation and, consequently, experience elevated instances of allopatric speciation. Microhabitat shifts can have decoupled effects on different dimensions of biodiversity, highlighting the need for nuance when interpreting the macroevolutionary consequences of ecological opportunity.

Advancing terrestrial biodiversity monitoring with satellite remote sensing in the context of the Kunming-Montreal global biodiversity framework

Satellite remote sensing (SRS) provides huge potential for tracking progress towards conservation targets and goals, but SRS products need to be tailored towards the requirements of ecological users and policymakers. In this viewpoint article, we propose to advance SRS products with a terrestrial biodiversity focus for tracking the goals and targets of the Kunming-Montreal global biodiversity framework (GBF). Of 371 GBF biodiversity indicators, we identified 58 unique indicators for tracking the state of terrestrial biodiversity, spanning 2 goals and 8 targets. Thirty-six shared enough information to analyse their underlying workflows and spatial information products. We used the concept of Essential Biodiversity Variables (EBV) to connect spatial information products to different dimensions of biodiversity (e.g. species populations, species traits, and ecosystem structure), and then counted EBV usage across GBF goals and targets. Combined with published scores on feasibility, accuracy, and immaturity of SRS products, we identified a priority list of terrestrial SRS products representing opportunities for scientific development in the next decade. From this list, we suggest two key directions for advancing SRS products and workflows in the GBF context using current instruments and technologies. First, existing terrestrial ecosystem distributions and live cover fraction SRS products (of above-ground biomass, ecosystem fragmentation, ecosystem structural variance, fraction of vegetation cover, plant area index profile, and land cover) need to be refined using a co-design approach to achieve harmonized ecosystem taxonomies, reference states and improved thematic detail. Second, new SRS products related to plant physiology and primary productivity (e.g. leaf area index, chlorophyll content & flux, foliar N/P/K content, and carbon cycle) need to be developed to better estimate plant functional traits, especially with deep learning techniques, radiative transfer models and multi-sensor frameworks. Advancements along these two routes could greatly improve the tracking of GBF target 2 (‘improve connectivity of priority terrestrial ecosystems), target 3 (‘ensure management of protected areas’), target 6 (‘control the introduction and impact of invasive alien species’), target 8 (‘minimize impact of climate change on biodiversity’), target 10 (‘increase sustainable productivity of agricultural and forested ecosystems’) and target 12 (‘increase public urban green/blue spaces’). Such improvements can have secondary benefits for other EBVs, e.g. as predictor variables for modelling species distributions and population abundances (i.e. data that are required in several GBF indicators). We hope that our viewpoint stimulates the advancement of biodiversity monitoring from space and a stronger collaboration among ecologists, SRS scientists and policy experts.

The role of functional and phylogenetic diversity in riparian tree vegetation on leaf litter breakdown in rivers

While how taxonomic diversity mediates changes in ecosystem function is well‐studied, how deeper dimensions of biodiversity drive important processes is understudied. The overarching goal of this work was to determine the role of these dimensions of biodiversity independently and/or interactively in explaining carbon processing in rivers. Here, we explicitly link community structure and subsequent traits of riparian forests to adjacent ecosystem processing of carbon (e.g. leaf litter). This was accomplished by examining how forests are actually structured in addition to experimental manipulations of phylogenetic and functional diversities of riparian forest community inputs of leaf litter to streams. Experimental field manipulations were carried out in three Piedmont headwater streams to answer the following questions: 1) does existing variation in taxonomic, functional and phylogenetic diversity of riparian communities differentially drive decomposition in rivers? And 2) independent of taxonomic diversity, how does functional and phylogenetic diversity of leaf litter assemblages influence rates of decomposition in rivers? We observed significant interspecific variation in breakdown among 30 riparian tree species, in addition to significant relationships between breakdown rate and important foliar tissue chemistries. Breakdown of mixtures that reflected the composition of the riparian species composition did not vary with functional nor phylogenetic diversity, but breakdown of litter mixtures was higher than that of single species. In a separate study, when manipulated independently, functional and phylogenetic diversity were positively related to breakdown, and explained similar degrees of variation. These results are important to understand in light of deepening knowledge of the role different dimensions of biodiversity take in explaining ecosystem function.

Safeguarding sloths and anteaters in the future: Priority areas for conservation under climate change

AbstractSloths and anteaters form the monophyletic order Pilosa, which is currently represented by only 16 extant species distributed exclusively in the Neotropics. This present‐day low species richness is an inheritance of the Pleistocene megafaunal extinctions, where over 65 Pilosa species known from the fossil record went extinct. The large number of species lost in the recent past suggests that this group is greatly vulnerable to extinction. Here, we propose long‐term priority conservation areas for the order Pilosa, considering different future climate change scenarios, biotic stability, and the multiple dimensions of the group's biodiversity, such as species richness, species endemism, and phylogenetic diversity. Projections of species distribution for future scenarios show increased fragmentation and clear habitat loss as the Amazon Forest is replaced by savanna‐like habitats. Conservation solutions were highly congruent for the different dimensions of biodiversity, with priority areas emerging mainly in the Atlantic Forest, Amazonian wetlands, highlands of Ecuador, and the Central American isthmus. Expanding the currently protected areas network by 6% with the proposed priority areas, independently of which future climatic scenario is considered, can increase sloths and anteaters' coverage in the future by 12%. As a group of high phylogenetic and ecological importance, future conservation planning should deliberately aim to protect areas favorable to Pilosa, especially given the current scenario of environmental dismantling and neglect of critical Neotropical biomes.Abstract in Portuguese is available with online material.

Disentangling direct and indirect effects of landscape structure on urban bird richness and functional diversity.

As fragmented landscapes become increasingly common around the world, managing the spatial arrangement of landscape elements (i.e., landscape configuration) may help to promote the conservation of biodiversity. However, the relative effects of landscape configuration on different dimensions of biodiversity across species assemblages are largely unknown. Thus, a key challenge consists in understanding when it is necessary to focus on landscape configuration, in addition to landscape composition, to achieve multifunctional landscapes. We tested the effects of landscape composition (the percentage of tree cover and built infrastructure) and landscape configuration (degree of fragmentation) on landscape-level species richness and different metrics of functional diversity of urban birds. We collected data on different bird guilds (nectarivores/frugivores, insectivores) from Brisbane, Australia. Using structural equation models, we found that landscape structure (landscape composition and configuration) affected functional diversity via two main pathways: (1) through effects of landscape composition, mediated by landscape configuration (indirect effects), and (2) through direct ("independent") effects of landscape composition and configuration, filtering species with extreme trait values. Our results show that landscape-level species richness declined with the extent of built infrastructure, but patterns of trait diversity did not necessarily correlate with this variable. Landscape configuration had a stronger mediating effect on some metrics of the functional diversity of insectivores than on the functional diversity of frugivores/nectarivores. In addition, fragmentation increased the effects of built infrastructure for some traits (body size and dispersal capacity), but not for others (habitat plasticity and foraging behavior). These results suggest that differential approaches to managing landscape structure are needed depending on whether the focus is on protecting functional diversity or species richness and what the target guild is. Managing landscape fragmentation in areas with high levels of built infrastructure is important if the objective is to protect insectivore species with uncommon traits, even if it is not possible to preserve high levels of species richness. However, if the target is to enhance both functional diversity and species richness of multiple guilds, the focus should be on improving composition through the reduction of negative effects of built infrastructure, rather than promoting specific landscape configurations in growing cities.

Identifying areas for multidimensional biodiversity conservation, with a case study in Oaxaca, Mexico

The greatest challenge that we currently face is generating integrative conservation strategies to guarantee the preservation not only of species richness, but also of ecological functions and evolutionary history. We propose to assess these different dimensions to identify areas of high multidimensional diversity (AMC), and exemplify this approach with cricetid mice, in a region of Mexico with high diversity that is considered a priority for global conservation. We elaborate models of the potential geographic distribution of 49 species of mice to predict their communities; we then used those predictions to calculate the number of rare species, and taxonomic, functional, and phylogenetic diversity. Subsequently, we identify AMC and evaluate their ecological integrity and the level to which they are protected by government and indigenous communities. We found a high spatial incongruity between the different dimensions of biodiversity, which indicates that in situ diversification processes and dispersal limitation drive spatial heterogeneous patterns of diversity. The AMC overlapped very little with the governmental (6.4%) and indigenous communities (15.2%) conservation areas, the Payments for Environmental Services initiative is the most overlaps. Half of the AMC had an intermediate ecological integrity. Protected areas systems protect few sites with high multidimensional biodiversity values, and half of the priority areas we identified requires restoration programs. The proposed methodology is an integral way to evaluate current protected areas systems and will be useful to guide effective and efficient conservation priorities involving evolutional and ecological dimensions of the biodiversity.

Scale Effects on the Relationship between Plant Diversity and Ecosystem Multifunctionality in Arid Desert Areas

Understanding the relationship between biodiversity and ecosystem multifunctionality is popular topic in ecological research. Although scale is an important factor driving changes in biodiversity and ecosystem multifunctionality, we still know little about the scale effects of the relationship between the different dimensions of biodiversity and ecosystem multifunctionality. Using plant communities in the northwest of the Qira Desert Ecosystem National Field Research Station of the Chinese Academy of Sciences in Qira County, Xinjiang, as the study object, we explored the scale effects of plant diversity and ecosystem multifunctionality at different sampling scales (5 m × 5 m, 20 m × 20 m, and 50 m × 50 m) and the relative contribution of different dimensions of diversity (species diversity, functional diversity, and phylogenetic diversity) to variation in ecosystem multifunctionality. At different scales, a significant scale effect was observed in the relationship between plant diversity and ecosystem multifunctionality. Species diversity dominated ecosystem multifunctionality at large scales (50 m × 50 m), and species diversity and ecosystem multifunctionality varied linearly between scales. Functional diversity made the greatest contribution in small scales (5 m × 5 m), and the relationship between phylogenetic diversity and ecosystem multifunctionality tended to show a single-peaked variation between scales, with a dominant effect on multifunctionality at the mesoscale (20 m × 20 m). The results of the study deepen the understanding of the scale effect of the relationship between plant diversity and ecosystem multifunctionality in arid desert areas, and help to further conserve plant diversity and maintain ecosystem multifunctionality.

Relationship between biodiversity and ecosystem multifunctionality along the elevation gradient in alpine meadows on the eastern Qinghai-Tibetan plateau

Exploring the spatial pattern of biodiversity in different dimensions and its relationship with ecosystem multifunctionality was one of the hot topics in ecological research, and elevation was an important topographic factor affecting biodiversity changes. The maintenance mechanism of ecosystem multifunctionality (EMF) relationship between different dimensions of biodiversity and ecosystem multifunctionality in alpine meadows on the eastern Qinghai-Tibetan Plateau was still unclear. This paper investigates the elevation patterns of species, functions, and phylogenetic diversity of plant communities in alpine meadows on the eastern Qinghai-Tibetan Plateau and their effects on EMF using factor analysis and the radial basis function (RBF) neural network model. The results showed that (1) the species and phylogenetic diversity indices (except MPD index) increased and then decreased with elevation; the functional diversity indices FRic and FEve showed a decreasing trend with elevation, while FDiv showed the opposite. (2) Ecosystem multifunctional indices for the five elevation gradients were 3000 m > 3250 m > 3500 m > 3750 m > 4000 m. There were significant correlations between biodiversity and ecosystem functions. Species richness, Simpson, FRic, and FDiv increased with increasing EMF, but the relationship between phylogenetic diversity and EMF was insignificant. (3) Among the biodiversity indices, species richness and functional richness indices had a greater impact on EMF and were also important drivers to explain changes in EMF, followed by PD indices. The high biodiversity of alpine meadows can contribute to the supply of multifunctional ecosystems, making them healthier and more stable.

Towards mapping biodiversity from above: Can fusing lidar and hyperspectral remote sensing predict taxonomic, functional, and phylogenetic tree diversity in temperate forests?

AbstractAimRapid global change is impacting the diversity of tree species and essential ecosystem functions and services of forests. It is therefore critical to understand and predict how the diversity of tree species is spatially distributed within and among forest biomes. Satellite remote sensing platforms have been used for decades to map forest structure and function but are limited in their capacity to monitor change by their relatively coarse spatial resolution and the complexity of scales at which different dimensions of biodiversity are observed in the field. Recently, airborne remote sensing platforms making use of passive high spectral resolution (i.e., hyperspectral) and active lidar data have been operationalized, providing an opportunity to disentangle how biodiversity patterns vary across space and time from field observations to larger scales. Most studies to date have focused on single sites and/or one sensor type; here we ask how multiple sensor types from the National Ecological Observatory Network’s Airborne Observation Platform (NEON AOP) perform across multiple sites in a single biome at the NEON field plot scale (i.e., 40 m × 40 m).LocationEastern USA.Time period2017–2018.Taxa studiedTrees.MethodsWith a fusion of hyperspectral and lidar data from the NEON AOP, we assess the ability of high resolution remotely sensed metrics to measure biodiversity variation across eastern US temperate forests. We examine how taxonomic, functional, and phylogenetic measures of alpha diversity vary spatially and assess to what degree remotely sensed metrics correlate with in situ biodiversity metrics.ResultsModels using estimates of forest function, canopy structure, and topographic diversity performed better than models containing each category alone. Our results show that canopy structural diversity, and not just spectral reflectance, is critical to predicting biodiversity.Main conclusionsWe found that an approach that jointly leverages spectral properties related to leaf and canopy functional traits and forest health, lidar derived estimates of forest structure, fine‐resolution topographic diversity, and careful consideration of biogeographical differences within and among biomes is needed to accurately map biodiversity variation from above.

Promoting Biodiversity Conservation Requires a Better Understanding of the Relationships Between Ecosystem Services and Multiple Biodiversity Dimensions

In order to reverse the global trend of biodiversity loss, the concept of ecosystem services has been widely applied to make policymakers and the general public realize that conserving biodiversity possesses both intrinsic and utilitarian values. However, to achieve this goal, it is necessary to first have a clear understanding of the relationships between biodiversity and ecosystem services (BES). To advance our understanding of this issue, we first reviewed the major progress in current BES studies, with an emphasis on three biodiversity dimensions (i.e., taxonomic diversity, functional diversity, and ecosystem diversity). Based on the findings, we then propose three research topics as future directions: (1) More direct and explicit studies on the effects of different dimensions of biodiversity on various ecosystem service types; (2) developing a biodiversity-based understanding of the formation of ecosystem services; (3) creation of science-based ecosystem management plans and policies that can maximize synergies between biodiversity conservation and ecosystem service enhancement. By conducting such research, we will be able to not only further understand the complex relationships between biodiversity and ecosystem services but also better promote the concept of ecosystem services for more successful biodiversity conservation in the future.

Common species contribute little to spatial patterns of functional diversity across scales in coastal grasslands

Abstract Spatial patterns of functional diversity are important in understanding community assembly as well as spatial variation in ecosystem functioning, yet the contribution of different species to these patterns remains unclear, making it difficult to generalise. Several studies have previously used a sequential addition approach to determine the subsets of species that contribute to the spatial distribution of species richness, frequently showing the importance of common species to richness patterns. This approach, however, has not been applied to functional diversity despite the central role of species traits in community ecology. Here we use a multiscale survey of plants from the Machair grassland system of the Western Isles of Scotland to ask the following questions: (i) Do functional diversity patterns correlate better with geographically common or geographically rare species?; (ii) Do their relative contributions vary with spatial scale?; and (iii) Do these patterns vary between functional diversity measures? We show that while species richness patterns correlate with geographically common species, common species contribute less than expected to spatial patterns of functional diversity at frequently used spatial monitoring scales. The relative contribution of species to overall biodiversity patterns, however, can vary with spatial scale. Synthesis. Surveying only common species may be inadequate for estimating spatial patterns of functional diversity, especially if using occurrence as opposed to percentage cover or abundance data, and spatial scale needs to be considered when designing surveys. Our approach highlights the species that may be adequate indicators of different dimensions of biodiversity and contributes to our understanding of the distribution of functional diversity in space.

Idea paper: Improving forecasts of community composition with lightweight biodiversity monitoring across ecological and anthropogenic disturbance gradients

AbstractAccurate and up‐to‐date biodiversity forecasts enable robust planning for environmental management and conservation of landscapes under a wide range of uses. Future predictions of the species composition of ecological communities complement more frequently reported species richness estimates to better characterize the different dimensions of biodiversity. The models that make community composition forecasts are calibrated with data on species' geographic patterns for the present, which may not be good proxies for future patterns. The future establishment of novel communities represents data on species interactions unaccounted for by these models. However, detecting them in a systematic way presents challenges due to the lack of monitoring data for landscapes with high environmental turnover, where such communities are likely to establish. Here, we propose lightweight monitoring over both ecological and anthropogenic disturbance gradients using passive sensors (i.e., those that operate continuously without much human input) to detect novel communities with the aim of updating models that make community composition forecasts. Monitoring over these two gradients should maximize detection of novel communities and improve understanding of relationships between community composition and environmental change. Further, barriers regarding cost and effort are reduced by using relatively few sensors requiring minimal upkeep. Ongoing updates to community composition forecasts based on novel community data and better understanding of the associated uncertainty should improve future decision‐making for both resource management and conservation efforts.

Geographic patterns and climate correlates of the deviation between phylogenetic and taxonomic diversity for angiosperms in China

Taxonomic diversity (TD) of areas within a region is often strongly and positively correlated with phylogenetic diversity (PD) of the areas. However, variation in speciation and extinction rates and the biogeographic histories of lineages can result in significant deviation of PD from TD (i.e., relative PD after correcting for TD; hereafter PDdev). Identifying areas with higher or lower PDdev within a region is important not only to understanding evolutionary processes associated with the causes of biodiversity patterns across the region but also to identifying areas to be protected for different dimensions of biodiversity. Here, we contrast geographic distributions of PD versus TD for angiosperms in China, explore geographic patterns of PDdev, identify areas where PD is much higher (hotspots) or much lower (coldspots) than expected based on TD, and relate the three diversity metrics to climate variables. We found that geographic patterns of TD were highly congruent with those of PD but they were incongruent with those of PDdev. Areas of unusually high PDdev were generally not those of high TD and PD. Biodiversity hotspots identified based on PDdev generally did not overlap with those identified based on TD and PD. We suggest that identifying areas to be protected should consider not only areas of high TD and PD but also areas of unusually high PDdev, because areas of high PDdev likely hold ancient evolutionary histories and uniqueness, and these areas may not overlap with those having high TD and PD.

Conservation risks and portfolio effects in mixed‐stock fisheries

AbstractFish biodiversity sustains the resilience and productivity of fisheries, yet this biodiversity can be threatened by overharvest and depletion in mixed‐stock fisheries. Thus, the biodiversity that provides benefits may also make sustainable resource extraction more difficult, a key challenge in fisheries management. We simulated a mixed‐stock fishery to explore relationships between different dimensions of biodiversity and fishery performance relative to conservation and fishery objectives. Different dimensions of biodiversity (number of stocks, evenness, asynchrony among stocks, heterogeneity in stock productivity) exacerbated trade‐offs between fishery and conservation objectives. For example, fisheries targeting stock‐complexes with greater asynchrony, and to a lesser extent richness, had greater stability in harvest through time but also greater risks of overfishing weak stocks and reduced yield compared to less biodiverse stock‐complexes. These trade‐offs were ameliorated by increasing management control—the capacity of fishery managers to harvest specific stocks. To explore these trade‐offs in real‐world fisheries, we contrasted the fishing and population status of individual stocks within three major mixed‐stock sockeye salmon (Oncorhynchus nerka, Salmonidae) fisheries—Bristol Bay, Fraser River, and Skeena River. In general, the fisheries with lower management control had individual stocks that were more often being over‐ or under‐fished, compared with those with higher management control, though variation among regions in biodiversity, scale of management, and magnitude of habitat alteration likely also contribute to these relationships. Collectively, our findings emphasize that there is a need to extract less or regulate better in order to conserve and benefit from biodiversity in fisheries and other natural resource management systems.

Spatial and temporal trends in different dimensions of macrophyte biodiversity in boreal lakes

To comprehensively understand the impact of anthropogenic activities on biodiversity, we must understand how biodiversity has changed over time and its underlying processes. Regardless of a recent increase in scientific interest towards changes in community composition, i.e. beta diversity, these changes have not been studied comprehensively in lake environments in a spatio-temporal framework. In addition, although biotic homogenisation has gained much attention in recent decades, it is still unclear how this process acts at different levels of biodiversity through time.
 The main aim of this thesis is to study temporal and spatial biodiversity patterns of vascular aquatic macrophyte communities in small boreal lakes during a period of 70 years. The focus is on beta diversity-environment relationships and different dimensions of biodiversity, with special attention to functional features. This thesis is based on three separate case studies that all have utilised temporal presence-absence data of vascular aquatic macrophytes from 27 to 28 lakes from the 1940s to the 2010s.
 Vascular aquatic macrophyte communities showed only moderately different spatial beta diversity patterns in relation to human impact across decades. The patterns of different dimensions of spatial beta diversity diverged only slightly from each other. The temporal change in aquatic macrophyte communities at the lake level has beenmodest since the 1940s. Nevertheless, it seems that even relatively modest changes in the environment affect temporal gains and losses of species at the lake level. There were no signs of either biotic homogenisation or biotic differentiation (taxonomic, phylogenetic or functional), but the changes in the environment have affected functional community composition and changes in functional richness to some extent.
 By using the spatial and temporal beta diversity perspective, this thesis highlights the fact that even though biotic homogenisation is a pervasive problem globally, it is not an unambiguous process acting similarly at all spatial and temporal scales or in different environments and different organism groups. There are likely five partly interdependent reasons why no signs of biotic homogenisation were detected in the study area during the 70-year study period: the modest changes in the environment from the 1940s to the 2010s, high ecological resilience of the lakes, information on species presence and absence was used instead of abundance data, biotic interactions and complex community-environment relationships together with stochastic processes and climate change.
 The results highlight that relying on only one or two survey points in time can result in limited knowledge of the ecological phenomenon under study, and an exceptional year in terms of weather conditions can hinder detecting overall long-term trends in compositional changes, especially under ongoing climate change. The patterns detected in macrophyte beta diversity are likely to represent situations in the extensive boreal and glaciated areas of Eurasia and North America, with largely similar species pools in many regions. Therefore, lakes across the boreal region and areas that have faced glaciation and postglacial processes might be resistant against moderate levels of human pressure.

Extending biodiversity conservation with functional and evolutionary diversity: a case study of South African sparid fishes

Designing marine protected area (MPA) networks has relied primarily on species- or habitat-based measures that assess spatial distributions of biodiversity. Molecular and functional data have the potential to unlock information regarding the evolutionary uniqueness and resilience of natural communities, making phylogenetic diversity (PD) and functional diversity (FD) effective tools for spatial planning. These are, however, rarely used in marine conservation planning. In South Africa, MPAs have been implemented to protect rare and valuable fishery resources, such as members of the Sparidae (seabreams), but have not considered different dimensions of biodiversity, such as its phylogenetic and functional components. Here, we mapped species distributions, phylogenetic relationships and functional features of the Sparidae in South Africa to refine how biodiversity is spatially structured for this species-rich taxonomic group. Our results show strong spatial similarities between PD and FD, suggesting that, for this group, PD is an effective surrogate for functional data. However, there was a mismatch between areas selected with different biodiversity metrics (particularly endemicity levels) and established MPAs, highlighting the need for integrated approaches to conserve this unique marine fauna.

Testing Darwin’s naturalization conundrum based on taxonomic, phylogenetic, and functional dimensions of vascular plants

AbstractCharles Darwin posited two alternative hypotheses to explain the success of nonnative species based on their relatedness to natives: nonnative species that are closely related to native species could experience (1) higher invasion success because of an increased probability of habitat suitability (conferred by trait similarity) or (2) lower invasion success due to biotic interference, such as competition and limiting similarity. The paradox raised by the opposing predictions of these two hypotheses has been termed “Darwin’s naturalization conundrum” (DNC). Using plant communities measured repeatedly across an experimental fire gradient in an oak savanna (Minnesota, USA) over 31 yr, we evaluated the DNC by incorporating taxonomic, functional, and phylogenetic information. We used a “focal‐species” approach, in which the taxonomic, functional, and phylogenetic structure of species co‐occurring with a given nonnative (focal) species in local communities was quantified. We found three main results: first, nonnative species tended to co‐occur most with closely related natives, except at the extreme ends of the fire gradient (i.e., in communities with no fire and those subjected to high fire frequencies); second, with increasing fire frequency, nonnative species were functionally more similar to native species in recipient communities; third, functional similarity between co‐occurring nonnatives and natives was stable over time, but their phylogenetic similarity was not, suggesting that dynamic external forces (e.g., climate variability) influenced the phylogenetic relatedness of nonnatives to natives. Our results provide insights for understanding invasion dynamics across environmental gradients and highlight the importance of evaluating different dimensions of biodiversity in order to draw stronger inferences regarding species co‐occurrence at different spatial and temporal scales.

Spatial incongruence in the species richness and functional diversity of cricetid rodents.

Biodiversity is multidimensional and different mechanisms can influence different dimensions. The spatial distribution of these dimensions can help in conservation decisions through the location of complementary areas with high diversity. We analyzed congruence in spatial patterns of species richness and functional diversity of cricetid rodents in the state of Oaxaca, southern Mexico, at different scales, and environmental variables related. Potential distribution models were produced for 49 species of cricetids in Maxent and superimposed to obtain potential communities in cells of 25, 50,100, 200 and 400 km2. We estimated species richness (SR) and functional diversity (SES.FD) eliminating the species richness effect through null models. The patterns and spatial congruence of species richness and functional diversity are described. The relationships between the environmental variables (elevation, temperature, precipitation, net primary productivity and potential evapotranspiration) and the SR and SES.FD were explored using Generalized Linear Models (GLMs) and Generalized Additive Models (GAMs). The highest species richness was found in mountainous ecosystems while the highest functional diversity was in tropical forests, revealing a spatial incongruence among these components of biodiversity (r = -0.14, p = 0.42; Pearson correlation). The locations of the cells of low congruence varied according to spatial resolution. In univariate models, elevation was the variable that best explained species richness (R2 = 0.77). No single variable explained the functional diversity; however, the models that included multiple environmental variables partially explained both the high and low functional diversity. The different patterns suggest that different historic, ecological and environmental processes could be responsible for the community structure of cricetid rodents in Oaxaca. These results indicate that one great challenge to be met to achieve more effective planning for biological conservation is to integrate knowledge regarding the spatial distribution of different dimensions of biodiversity.

Partitioning multiple diversity dimensions of nearshore fish assemblages within a coastal seascape

The conservation of coastal seascapes requires a better understanding of how different dimensions of biodiversity are represented between juxtaposed habitats. We explored patterns of taxonomic, functional, and phylogenetic diversity of fishes between four habitats (sandy bottoms, rocky reefs of high and low relief, and mixed bottoms) within a semi-lagoon seascape (Las Canteras beach) in Gran Canaria Island. Data on fish presence in each habitat were provided by weekly snorkeling tours, at day and night, from August 2015 to August 2018. Indices that measured ‘how much’ biodiversity, i.e., ‘how many species’ (species richness), ‘how much functional dissimilarity’, and ‘how much evolutionary history’ were larger on rocky bottoms. However, indices that measured phylogenetic differentiation, i.e., ‘how different’, via the taxonomic distinctiveness and the Mean Pairwise Distance index were particularly high on sandy bottoms, because of the presence of elasmobranchs, which were absent from rocky bottoms. The ‘phylogenetic signal’, whether phylogenetically related species are functionally similar, was significant on rocky bottoms, but non-significant on sandy bottoms, reflecting phylogenetic ‘overdispersion’ on sandy bottoms and phylogenetic ‘clustering’ on hard bottoms. From a conservation perspective, sandy bottoms cannot be underrated, particularly in the context of maximizing indices that measure ‘how phylogenetically different’ biodiversity is.

A latitudinal gradient in dimensionality of biodiversity

Biodiversity is multifaceted and represents numerous dimensions expressing variation in richness and abundances of species, ecosystem functions, phylogenetic relationships, morphology, traits and interactions. Such dimensions are correlated to varying degrees and recent research has attempted to better understand behavior of such correlations. We define dimensionality of biodiversity as degree of redundancy in variation among multiple dimensions of biodiversity. One fundamental question regarding biodiversity is whether its dimensionality is spatially structured, also exhibiting geographic gradients. We examine if redundancy among dimensions of biodiversity changes latitudinally thereby contributing to increased tropical complexity. Geographic range maps of bats were overlaid on a 100 × 100 km grid of the New World to determine species composition of each cell. Species richness and three measures each of phylogenetic, functional and phenetic diversity were calculated. Dimensionality was estimated as evenness of eigenvalues generated from a principal components analysis (PCA) of multiple measures of biodiversity. High dimensionality is characterized by low correlations among biodiversity measures and high evenness of eigenvalues from PCA, whereas low dimensionality is characterized by high correlations and low evenness of eigenvalues. Latitudinal gradients of dimensionality were determined by regression analysis. Slope of the empirical relationship was compared to slopes generated from two null models that randomized the distribution of species. Dimensionality of biodiversity does indeed exhibit a latitudinal gradient, decreasing with increasing latitude. This empirical gradient was stronger than expected by the random distribution of species. Additionally, spatial variation in dimensionality of biodiversity could not be explained by a similar underlying pattern in variation of environmental conditions. Correlations among different dimensions of biodiversity vary spatially, and interpretations of such correlations should be geographically explicit. Mechanisms proposed to explain latitudinal gradients need not only account for gradients of biodiversity, but gradients in dimensionality as well. A gradient in dimensionality suggests that conservation strategies that rely on maximization of a single metric, such as species richness, might be of varying utility in different geographic contexts.