Analysis Of Functional Diversity Research Articles

Gustatory Receptor 206 Participates in the Foraging Behavior of Larvae of Polyphagous Pest Spodoptera litura.

Insect gustatory receptors (GRs) aid in the precise identification of deterrent or stimulant compounds associated with food, mating, and egg-laying. Thus, they are promising targets for developing efficient insecticides. Here, 61 GRs in the chemosensory organs of Spodoptera litura larvae and adults were identified. Among them, SlitGR206 exhibited larval labium (LL)-specific expression characteristics. To explore the role of SlitGR206, a bacterial expression system was established to produce high-quality double-stranded RNA (dsRNA) and suppress SlitGR206 expression in LL. Subsequent behavioral assessments revealed that SlitGR206 silencing influenced larval feeding preferences and absorption. Moreover, it was found to reduce the ability of larvae to forage the five crucial host odorants. These findings demonstrate that SlitGR206 likely plays an indirect regulatory role in host recognition, consequently affecting foraging behavior. This provides a crucial foundation for the analysis of functional diversity among insect GRs and the precise development of nucleic acid pesticides in the future.

A meta‐analysis of the effects of anthropogenic disturbances on tropical mammal functional diversity

Abstract Understanding the processes that shape biological communities under a variety of perturbations is a central challenge in ecology and conservation. Mammals contribute to critical functional processes of an ecosystem, such as seed dispersal to maintain forest carbon stocks. The analysis of functional diversity, which measures the range and value of the ecological traits of organisms, provides critical information to understanding the link between biodiversity and ecosystem functioning. A growing number of studies have investigated the effects of anthropogenic disturbances on mammalian functional diversity; however, their results are very heterogeneous. Here, we conduct a comprehensive meta‐analysis of the effects of such anthropogenic disturbances on mammalian functional diversity in the tropics. We highlight major trends and analyse the influence of the type of anthropogenic disturbance, subgroups, and the functional diversity index used/applied. Our results indicate a negative effect of anthropogenic disturbances on mammalian functional diversity, particularly on functional richness (FRic) and functional dispersion (FDis). Habitat isolation was the stressor with the strongest effect, while agriculture and urbanisation showed a positive link with functional diversity. These results indicate that anthropogenic disturbances not only affect taxonomic diversity, but also reduce the functional diversity of mammals, which is likely to affect ecosystem functioning and possibly ecosystem service provision.

Assessing Microbial Diversity in Páramo Soils (Multistrategy Analysis): Effects of Potato Farming and Livestock Grazing in Nevados National Natural Park, Colombia

High Andean Páramos are very fragile neotropical ecosystems. Moreover, biodiversity in these areas is threatened by the anthropic activities of agriculture, cattle raising, and mining and has been little studied. Changes associated with potato farming and livestock grazing on microorganisms of Páramo soil of the Nevados National Natural Park (Nevados NNP) were assessed by (1) determination of physical and chemical properties (physicochemical matrix) and enzymatic activities associated (enzymatic activity matrix) with different biogeochemical cycles (C, N, and P); (2) microbial community functional diversity via evaluation of functional groups associated with carbon, nitrogen, and phosphorus cycles using cultivation-dependent techniques (arable functional group matrix and most probable number matrix); and (3) microbial diversity using cultivation-independent techniques that employ the hypervariable V5–V6 region of the 16S rRNA gene and pyrosequencing (16S-454 genus matrix and 16S-454 OTU matrix). Four of the six evaluated matrices (physicochemical, enzymatic activities, most probable number, and arable functional groups) revealed significant differences according to land use. The strategy adopted by the arable functional group matrix, in which the diversity of nitrogen fixation, phosphate solubilization, and cellulolytic compounds was evaluated, showed the most significant impacts of the different factors (land use, season, and elevation), especially those caused by potato cultivation and livestock. These results indicate that the initial impacts of potato farming and livestock grazing on the microbial community in El Bosque Village are better detected by functional diversity analysis than by molecular analysis of the 16S rRNA gene V5–V6 variable region. The results may have been caused by the type of molecular marker used in the analyses and the type of agricultural practices used by peasant farmers, which affect the functional diversity of the soil community. Among these practices are the maintenance of fallow periods greater than 7 years between each potato crop and the small proportion of cattle in relation to the total land area of the village. As the findings can be interpreted as an indicator of the early impacts of potato cultivation and livestock on microbial diversity, the effects of implementing community management plans, applying agroecological models, retaining biocultural memory, and changing agrarian structure are relevant for mitigating future changes.

Length-Weight Relationships for 32 Species of Cryptobenthic Reef Fishes from the Red Sea

Cryptobenthic reef fishes (CRFs) are often neglected in reef biodiversity assessments, trophodynamic studies, and biomass models. This oversight is due to the challenges associated with recording them in traditional underwater visual surveys and the scarcity of literature detailing their life history, ecology, and body growth parameters. Given their pivotal role in the functioning and maintenance of coral reef ecosystems, addressing these information gaps for CRF species is of great importance. In this study, we have computed the length-weight relationships (LWRs) for 32 CRF species spanning seven families in the Red Sea. This marks the first comprehensive report of LWR parameters for CRFs from this region, and for 31 of these species, it serves as their first LWR data report. The coefficient of determination (r2) ranged from 0.82 to 0.99, indicating a good fit for the LWRs. Half of the presented species belong to the Gobiidae family, including three undescribed species. In addition, we present LWRs for species from the families Blenniidae (5 spp.), Tripterygiidae (2 spp.), Apogonidae (4 spp.), Pseudochromidae (3 spp.), Plesiopidae (1 spp.), and Scorpaenidae (1 spp.). This research contributes invaluable insights into the growth patterns of CRFs not only in a global context but also beyond, as 50% of the recorded species are endemic to the region. The data generated holds great significance for conducting functional diversity analyses, ecosystem assessments, and coral reef health monitoring. By capturing this critical information, this work provides foundational metrics to take significant strides toward the conservation of these essential coral reef fishes.

Applying network analysis to measure functional diversity in food webs

Functional diversity is the heterogeneity in the functional roles of organisms in an ecosystem. Because the morphological traits of species dictate their functional roles, morphological trait diversity has traditionally been used as a proxy for functional diversity. However, species are embedded in a food web and their functional roles also depend on their network positions therein, therefore we argue that functional diversity can also be viewed from a network perspective. We therefore analysed food webs derived from 92 aquatic ecosystems. For every species in a food web, we measured its network position using several indices. Each of the indices emphasize a specific network characteristic, and we consequently call them “species network traits”. We then subjected these network traits to conventional functional diversity analysis to quantify the network-based functional diversity of an ecosystem. We show that high network-based functional diversity is typical of food webs with large network size, sparse in their organization, highly modular structure, or low network cohesion. We further show that our network-based functional diversity correlates weakly with its conventional morphological trait-based counterpart, and thus it provides an additional view on ecological functioning.

Comparative analysis of functional diversity of rumen microbiome in bison and beef heifers.

Ruminants play a key role in the conversion of cellulolytic plant material into high-quality meat and milk protein for humans. The rumen microbiome is the driver of this conversion, yet there is little information on how gene expression within the microbiome impacts the efficiency of this conversion process. The current study investigates gene expression in the rumen microbiome of beef heifers and bison and how transplantation of ruminal contents from bison to heifers alters gene expression. Understanding interactions between the host and the rumen microbiome is the key to developing informed approaches to rumen programming that will enhance production efficiency in ruminants.

Molecular Identification and Fungal Diversity Associated with Diseases in Hass Avocado Fruit Grown in Cauca, Colombia.

Hass avocado fruit diseases are one of the main marketing constraints in Colombia. To identify and reveal the diversity of fungi associated with diseases in fruits and peduncles, symptomatic samples were collected from 67 farms in the 9 main Hass avocado-producing municipalities of the department of Cauca located in southwestern Colombia. A total of 237 monosporic isolates were obtained that were subjected to DNA extraction, amplification of the ITS region, sequencing and functional diversity analysis based on Hill numbers by municipality and altitude. The results indicated that the genera Pseudocercospora, Diaporthe, Colletotrichum, Neofusiococcum, Lasiodiplodia and Pestatoliopsis were associated with fruit diseases. The genus with the highest number of effective species was Colletotrichum. The ITS region revealed 100% identity of the species Pseudocercospora norchiensis, which was the first report of this pathogen in the crop. There was a greater richness and diversity of associated species in the three municipalities, revealing that the higher the altitude was, the lower the richness and diversity of fungi associated with fruit diseases. These results will provide a better understanding of the identification and diversity of pathogenic microorganisms present in avocado production systems in this region of Colombia.

Functional diversity and spatial association analyses at different spatial scales reveal no changes in community assembly processes along an aridity gradient in the Atacama Desert

The structuring of plant assemblages along environmental gradients is typically explained by shifts from competition (limiting similarity) to environmental filtering as the environment becomes more stressful. However, facilitation, weaker-competitor exclusion, environmental heterogeneity, and the colonization-competition tradeoff can also structure plant assemblages along gradients. These assembly processes act on different plant traits and organs, and their prevalence varies with respect to the spatial scale. Using patterns of functional diversity, coupled with patterns of species association at two spatial scales, here we discern the assembly processes that structure shrub communities in four localities along an aridity gradient of the Atacama Desert. At each site, we calculated functional dispersion indexes for above- and below-ground traits, and patterns of species association at a patch and neighborhood scale. Our results revealed that at the patch scale in intermediate levels of aridity, the dominant assembly process was within-site environmental heterogeneity. At the neighborhood scale, communities are assembled mainly through random processes. Nonetheless, in some communities, the dominant assembly process was competition via limiting similarity or exclusion of the weaker competitor, and these did not change along the gradient. Together, these results reveal that environmental heterogeneity and competition are the main drivers of plant community assembly in a hyper-arid environment.

Uncovering the Prokaryotic Diversity of the Bathyal Waters above the Kuril–Kamchatka Trench

The Kuril–Kamchatka Trench (North-West Pacific Ocean) is included in the deepest trenches (>9000 m). This study is the first that aims at uncovering the bathyal prokaryotic diversity (1000–2000 m) of this fascinating extreme environment. The analysis of α-diversity revealed that bacterial communities showed greater diversity than archaeal communities and that both communities were characterized by poor evenness (indicative of the presence of few dominant OTUs). The metabarcoding analysis showed that Proteobacteria (65.5–90.7%), Bacteroidetes (2.4–10.7%), and Actinobacteria (2.5–9.6%) were the highly represented phyla of bacteria, with Acinetobacter (21.5–62.5%) as the most abundant genus. Moreover, the recently described Pseudofrancisella genus, which has been isolated from estuarine environments, has been found among the major bacterial taxa. This work represents the first report stating the presence of this genus in bathyal waters. The archaeal communities were dominated by the phylum Thaumarchaeota (53.6–94.0%), with Nitrosopumilus (53.6–94%) as its representative genus. The functional diversity analysis revealed that overall, the bacterial communities had a higher involvement in the carbon and nitrogen biogeochemical cycles, with chemoheterotrophy (mostly aerobic), aromatic compound degradation, and nitrate reduction as the most represented functions. In the archaeal communities, the most represented ecological function was the aerobic oxidation of ammonia (first stage of nitrification), a functional feature characteristic of Nitrosopumilus.

Toward a common set of functional traits for soil protists

Protists are major actors of soil communities and play key roles in shaping food webs, community assembly, and ecosystem processes, yet their functional diversity is understudied. High-throughput sequencing data have revealed their ubiquity and diversity, but lack of standardized traits has hampered the integration of functional information, limiting our understanding of soil ecosystems. Here, we propose a functional framework for soil protists, identify a set of common traits to characterize their functional diversity, and apply the framework on a broad-scale, real-world dataset. We reviewed studies on soil protists to identify the traits used in the literature, and define a framework based on 10 key traits that satisfy two criteria: availability of information, and applicability to most taxa. The framework was tested on a dataset of environmental DNA metabarcoding data from 1123 soil samples collected in 48 glacier forelands worldwide. Traits were assigned to the 570 Molecular Operational Taxonomic Units (MOTUs) detected in our dataset, leading to the production of a global trait-based dataset from glacier forelands. We estimated the functional space of protist communities and evaluated if the selected traits were effective in describing protist diversity. The functional space of protist communities showed that the MOTUs are clustered in three regions, mainly reflecting different nutritional and habitat preferences. The proposed framework is appropriate for multiple applications, including estimation of functional diversity and food web analyses, and provides a basis for ecological studies on soil protists, enabling the functional characterization of this essential but often neglected component of soil biodiversity.

Origin, evolution and diversification of plant mechanosensitive channel of small conductance-like (MSL) proteins

Mechanosensitive (MS) ion channels provide efficient molecular mechanism for transducing mechanical forces into intracellular ion fluxes in all kingdoms of life. The mechanosensitive channel of small conductance (MscS) was one of the best-studied MS channels and its homologs (MSL, MscS-like) were widely distributed in cell-walled organisms. However, the origin, evolution and expansion of MSL proteins in plants are still not clear. Here, we identified more than 2100 MSL proteins from 176 plants and conducted a broad-scale phylogenetic analysis. The phylogenetic tree showed that plant MSL proteins were divided into three groups (I, II and III) prior to the emergence of chlorophytae algae, consistent with their specific subcellular localization. MSL proteins were distributed unevenly into each of plant species, and four parallel expansion was identified in angiosperms. In Brassicaceae, most MSL duplicates were derived by whole-genome duplication (WGD)/segmental duplications. Finally, a hypothetical evolutionary model of MSL proteins in plants was proposed based on phylogeny. Our studies illustrate the evolutionary history of the MSL proteins and provide a guide for future functional diversity analyses of these proteins in plants.

Avian Taxonomic and Functional Diversity in Contrasting Habitats: A Comparative Study of Urban and Remote Forests in Arusha, Tanzania

Urbanisation globally transforms landscapes, impacting biodiversity significantly. In Arusha, Tanzania, rapid urban expansion accentuates the interplay between urbanisation and avian biodiversity. This study investigates urbanisation's influence on avian communities in two contrasting forested habitats: the urban "Themi River Forest" and the remote "Lake Duluti Forest." We explore taxonomic and functional avian diversity, elucidating underlying mechanisms. Taxonomic diversity analysis reveals "Lake Duluti Forest" with slightly higher species richness and "Themi River Forest" with a more even species distribution, reflecting urbanisation's influence. This aligns with global trends indicating reduced urban species richness due to habitat fragmentation. The urban forest, however, demonstrates avian adaptability to urbanised landscapes. Functional diversity analysis uncovers "Lake Duluti Forest" with greater functional richness, indicating a wider array of ecological roles. In contrast, "Themi River Forest" maintains comparable functional evenness, suggesting ecological balance despite urbanisation. Both forests exhibit distinct ecological niches, highlighting avian community flexibility. These findings hold significance for avian conservation and urban planning in Arusha and similar urbanising regions. Higher taxonomic diversity in remote forests underscores conservation importance. The urban forest showcases avian adaptability, emphasising green spaces in urban planning. Long-term conservation should protect both urban and remote forests, integrating strategies for avian habitat preservation and connectivity. This study advances understanding of urbanisation, forest type, and avian biodiversity's intricate relationship, offering insights for effective conservation in evolving urban landscapes

Detecting sediment recovery below an offshore longline mussel farm: A macrobenthic Biological Trait Analysis (BTA)

Expansion of bivalve aquaculture offshore reports lower environmental impacts compared to inshore farms. Taking a Before-After Control-Impact approach, this study presents the first functional diversity analysis and long-term Biological Trait Analysis (BTA) of infauna functional traits following the development of the United Kingdom's first large-scale, offshore longline mussel farm. Located in an area historically impacted by mobile fishing gear, farm sites had the greatest number of taxa and abundance compared to control sites. Functional diversity varied significantly across treatments (farm, near control, far control); while Functional Diversity, Richness, Divergence and Dispersion increased over time within the farm, Functional Evenness and Redundancy decreased. Bioturbation, body size, diet, feeding mode, life span, motility, sediment position, sensitivity and substrate type were chosen for Community-level Weighted Mean analysis, depicting the most frequently affected biological traits by shellfish farming. Farm sites developed a wider range of traits enhancing ecosystem function and habitat recovery after years of seabed damage. Outcomes support the use of functional diversity and BTA analysis to perform ecosystem assessment, supporting decision-makers implement policy and management.

Gut microbiome profile of Chinese hypertension patients with and without type 2 diabetes mellitus

BackgroundThe coexistence of hypertension and type 2 diabetes mellitus (T2DM) may largely increase the risk for cardiovascular disease. However, there is no clear consensus on the association between hypertension and the risk of diabetes. Gut microbiota plays important roles in the development of hypertension and T2DM, but whether there is difference between hypertension patients with or without T2DM has not been explored yet.MethodsWe recruited 101 hypertension patients in this study (72 patients without T2DM named HT group and 29 patients with T2DM named HT-T2DM group). Their blood samples were collected for testing clinical characteristics and fecal samples were tested for bacterial DNA using 16 S ribosomal RNA gene sequencing targeting the V3 and V4 region. The data of 40 samples were downloaded from project PRJNA815750 as health control (HC group) in this study. The community composition and structure of the microbiome, taxonomic difference, co-occurrence network and functional enrichment were analyzed by alpha/beta diversity, LEfSe, Fruchterman Reingold’s algorithm and PICRUSt2 functional analysis, respectively.ResultsAlpha and beta diversity analysis showed significant differences in microbial community richness and composition among the three groups. The HC group had a significantly higher Simpson index and a distinct microbiota community compared to the HT and HT-T2DM groups, as demonstrated by significant differences in unweighted and weighted UniFrac distances. The LEfSe analysis identified specific taxa that had significantly different abundance among the groups, such as Bacteroides uniformis, Blautia wexlerae, Alistipes putredinis, and Prevotella stercorea in the HC group, Prevotella copri and Phascolarctobacterium faecium in the HT group, and Klebsiella pneumoniae in the HT-T2DM group. Co-occurrence network analysis indicates that Prevotella copri, Mediterraneibacter gnavus, Alistipes onderdonkii and some unidentified species act as key nodes in the network. Differentially functional pathway identified by PICRUSt2 were concentrated in nutrition and energy metabolism, as well as the biosynthesis of other secondary metabolites.ConclusionsOur study found significant differences in microbial community richness, composition, and function among the healthy controls, hypertension patients with and without T2DM. Some specific taxa may explain this difference and serve as potential therapeutic targets for hypertension, T2DM, and their coexistence.

Single-cell analysis of human MAIT cell transcriptional, functional and clonal diversity

Mucosal-associated invariant T (MAIT) cells are innate-like T cells that recognize microbial metabolites through a semi-invariant T cell receptor (TCR). Major questions remain regarding the extent of human MAIT cell functional and clonal diversity. To address these, we analyzed the single-cell transcriptome and TCR repertoire of blood and liver MAIT cells and developed functional RNA-sequencing, a method to integrate function and TCR clonotype at single-cell resolution. MAIT cell clonal diversity was comparable to conventional memory T cells, with private TCR repertoires shared across matched tissues. Baseline functional diversity was low and largely related to tissue site. MAIT cells showed stimulus-specific transcriptional responses in vitro, with cells positioned along gradients of activation. Clonal identity influenced resting and activated transcriptional profiles but intriguingly was not associated with the capacity to produce IL-17. Overall, MAIT cells show phenotypic and functional diversity according to tissue localization, stimulation environment and clonotype.

Functional Response of Aquatic Macroinvertebrate Communities to Temporality in Tropical Temporary Ponds

Temporary or stationary wetlands (ponds) are bodies of shallow water that experience periodic droughts and an irregular flood cycle throughout the year. Although these wetlands are widely distributed in the Colombian territory, there have been few studies on their ecology. The aim of this research is to determine the effects of hydroperiod on the functional diversity of aquatic and semiaquatic macroinvertebrates in five temporary ponds in the department of Magdalena (Colombia). The samplings were performed during the hydroperiods of the filling and drying phases. Samples were collected from all the microhabitats present (sediment, littoral, and limnetic zones). Correlation analyses were performed between the traits and sites in the two hydroperiods, and a multidimensional and comparative analysis of functional diversity was performed, where indices of distance, richness, and functional dispersion were calculated in each hydroperiod. Statistical differences in functional replacement were found for only one of the ponds; however, the other ponds showed a similar trend. These results fit the functional turnover ecological hypothesis in that the response of the aquatic and semiaquatic macroinvertebrate communities was associated with the hydroperiod of the ponds based on the habitat “templet” theory.

Analysis of short-term and local scale variations in fish community structure in Dachen Island waters

Understanding the changes in community structure of fishery resources in island reef waters is crucial for effective fishery resource management, as these waters constitute a critical link in maintaining the sustainable development of offshore fishery resources. The study analyzed the structure of the fish community in the waters surrounding Dachen Island by using data collected during four voyage surveys conducted between September 2020 and April 2021. The study utilized co-occurrence network analysis, multiple regression trees, and functional diversity analysis to investigate the short-term and local scale changes in fish community structure. The results showed that the fish community in the waters adjacent to Dachen Island can be categorized into two groups: annual and stage-use species. The stage-use species include Scoliodon laticaudus, Trichiurus lepturus, Tetraodontidae, and others, which are used during the summer and autumn stages of bait migration. Additionally, Dasyatidae and others, which used during the winter and spring stages of reproductive migration. Furthermore, the study found that the habitats dominated by nearshore rocky habitats and distant deep habitats formed the local scale variation in community structure in island waters. The integrated analysis of species α-diversity and functional diversity provided a basis for understanding the mechanisms of biodiversity action. Our study aims to provide a theoretical framework for the development of fishery resource management strategies based on the life cycle of fish, and to serve as a reference for the prioritization of key protection areas for fishery resources in island and reef environments. Overall, the study’s findings can promote the understanding of community structure dynamics in island waters. Additionally, these findings can offer valuable insights into the restoration of habitats and the implementation of marine ranching activities in Dachen Island. Moreover, the outcomes can serve as a theoretical foundation for the development of appropriate management and conservation strategies for fisheries resources.

Effect of Canal Bank Engineering Disturbance on Plant Communities: Analysis of Taxonomic and Functional Beta Diversity

We aimed to determine how patterns of functional and taxonomic dissimilarities and their components differ between disturbed and undisturbed plant communities. Taxonomic (species) and functional (trait) diversity are key aspects of biodiversity, and their respective dissimilarities are important in diversity scaling and for informing conservation. We utilized a pseudo-experimental setting, the Basingstoke Canal, UK, where sections of canal bank have been repaired over a four-year period and are interspersed with sections left undisturbed. We collected plant community data, computed functional beta diversity and taxonomic beta diversity and partitioned them into species loss and replacement components. We compared disturbed and undisturbed plots with respect to these dissimilarity measures, the time since disturbance, invasive species, plant life-forms and environmental dissimilarity. We found high levels of taxonomic (85–90%) and functional (70–76%) dissimilarities between disturbed and undisturbed sites, primarily driven by turnover. The total dissimilarity was lower for functional dissimilarity than taxonomic dissimilarity. Disturbed sites had greater between-site taxonomic and functional dissimilarities and lower plant abundances than undisturbed sites, driven by both turnover and nestedness components. The disturbed site functional diversity diverged strongly from null expectations. We found no significant effects of time since disturbance, environmental variables or invasive species, possibly indicating the dominance of stochastic, local-scale processes. However, disturbed sites had lower levels of phanerophyte richness and higher levels of therophyte richness. Our results indicate that small-scale disturbances may increase taxonomic and functional between-community dissimilarities in anthropogenic habitats without increasing invasive species, lending support to local-scale conservation that enhances habitat heterogeneity to promote taxonomic diversity and its corresponding biotic functions.

N‐dimensional hypervolumes in trait‐based ecology: Does occupancy rate matter?

Abstract Many methods for estimating the functional diversity of biological communities rely on measuring geometrical properties of n‐dimensional hypervolumes in a trait space. To date, these properties are calculated from individual hypervolumes or their pairwise combinations. Our capacity to detect functional diversity patterns due to the overlap of multiple hypervolumes is, thus, limited. Here, we propose a new approach for estimating functional diversity from a set of hypervolumes. We rely on the concept of occupancy rate, defined as the mean or absolute number of hypervolumes enclosing a given point in the trait space. Furthermore, we describe a permutation test to identify regions of the trait space in which the occupancy rate of two sets of hypervolumes differs. We illustrate the utility of our approach over existing methods with two examples on aquatic macroinvertebrates. The first example shows how occupancy rate relates to the stability of trait space utilisation due to increased flow intermittency and allows the identification of taxa in regions of the trait space with low occupancy rates. The second example shows how the permutation test based on occupancy rates can detect differences in trait space utilisation due to river morphology variation even with a high degree of overlap among input hypervolumes. Our newly developed approach is particularly suitable in functional diversity analysis when investigating patterns of overlap among multiple hypervolumes. We emphasise the need to consider analyses based on occupancy rate into functional diversity estimation. Read the free Plain Language Summary for this article on the Journal blog.

Generalized network density matrices for analysis of multiscale functional diversity.

The network density matrix formalism allows for describing the dynamics of information on top of complex structures and it has been successfully used to analyze, e.g., a system's robustness, perturbations, coarse-graining multilayer networks, characterization of emergent network states, and performing multiscale analysis. However, this framework is usually limited to diffusion dynamics on undirected networks. Here, to overcome some limitations, we propose an approach to derive density matrices based on dynamical systems and information theory, which allows for encapsulating a much wider range of linear and nonlinear dynamics and richer classes of structure, such as directed and signed ones. We use our framework to study the response to local stochastic perturbations of synthetic and empirical networks, including neural systems consisting of excitatory and inhibitory links and gene-regulatory interactions. Our findings demonstrate that topological complexity does not necessarily lead to functional diversity, i.e., the complex and heterogeneous response to stimuli or perturbations. Instead, functional diversity is a genuine emergent property which cannot be deduced from the knowledge of topological features such as heterogeneity, modularity, the presence of asymmetries, and dynamical properties of a system.