Dispersal Networks Research Articles

Structure, spatial dynamics, and stability of novel seed dispersal mutualistic networks in Hawai'i.

Increasing rates of human-caused species invasions and extinctions may reshape communities and modify the structure, dynamics, and stability of species interactions. To investigate how such changes affect communities, we performed multiscale analyses of seed dispersal networks on O'ahu, Hawai'i. Networks consisted exclusively of novel interactions, were largely dominated by introduced species, and exhibited specialized and modular structure at local and regional scales, despite high interaction dissimilarity across communities. Furthermore, the structure and stability of the novel networks were similar to native-dominated communities worldwide. Our findings suggest that shared evolutionary history is not a necessary process for the emergence of complex network structure, and interaction patterns may be highly conserved, regardless of species identity and environment. Introduced species can quickly become well integrated into novel networks, making restoration of native ecosystems more challenging than previously thought.

Invasive birds spread native seeds

Ecological Networks When humans introduce exotic species to sensitive ecosystems, invasion and extinction of native species often follow. The resulting ecological communities can develop unusual interactions between the survivors and newcomers. Vizentin-Bugoni et al. analyzed the structure of seed dispersal networks in Hawai'i, where native bird species have been mostly replaced by invaders. They found that the native plants now depend on the invasive birds for seed dispersal. The network of dispersal interactions is complex and stable, which are features of native seed-dispersal networks in other parts of the world. It appears that introduced species may, in some circumstances, become integrated into native ecosystems. Science , this issue p. [78][1] [1]: /lookup/volpage/364/78?iss=6435

Driver's Seat: Understanding Divergent Zoochorous Dispersal of Propagules

The mechanisms which underpin passive dispersal (zoochory) of organisms (or propagules) by other, usually more mobile animals (vector species), are frequently poorly understood. While certain dispersal networks have received considerable scientific interest, basic questions concerning the relative importance of vector species, propagule survival, and likely dispersal distances, often remain unanswered. Here, we propose and apply a series of novel metrics, the Dispersal Potential (DP), the Relative Dispersal Potential (RDP) and the Combined Dispersal Potential (CDP), to predict and classify likely dispersal and vector importance. In essence, DP = Np × Tv, whereby Np is the per capita propagule load (e.g. mean, minimum, or maximum abundance) or species richness of propagules carried per individual vector species, while Tv is the total number of possible vectors (e.g. individuals of a single species at a source site, local scale abundances, or entire continental populations). Further, the ratio based metric RDP allows for DP comparison between species, while the CDP accumulates the DP of a variety of vector species. An additional Relative CDP (RCDP) metric facilitates comparison between the CDP for multiple vectors to that of one or more additional vectors. The proposed metrics can also be used to assess intraspecific differences (e.g. ontogeny or reproductive status). Accordingly, we examine a variety of case studies and present calculations to ascertain the usefulness of our proposed metrics. Finally, we argue that adoption of these metrics and variants thereof, will enhance understanding of zoochory within and across dispersal networks.

Seeds and the City: The Interdependence of Zoochory and Ecosystem Dynamics in Urban Environments

The increasing urban sprawl has contributed to the extensive fragmentation and reduction of natural habitat worldwide. Urbanization has a range of adverse effects on ecosystem functioning, including the disruption of plant dispersal processes across the landscape. Urban fragmentation can alter the distance and directionality of dispersal, leading to disrupted gene flow among populations. The dispersal processes of plants that rely on animal-mediated dispersal (zoochory) may be disproportionately affected by urbanization, as many animals avoid urban areas or restrict their movements within urban habitats. This could alter the efficiency of animal dispersal vectors and modify seed movements across urban habitats. While recent studies suggest that seed dispersal networks can be complex and dynamic even in highly managed green areas with relatively low biodiversity, zoochory in urban environments remains understudied. We synthesize the existing literature on zoochory in urban environments and place the findings in the context of ecosystem dynamics. We assess the ecological and evolutionary consequences for seed dispersal following urbanization by considering how zoochory is affected by specific features of urban environments. These include the complexity of habitats with varying continuity; high disturbance and intense management; a high proportion of alien species combined with low natural biodiversity; animal behavioral adjustments in different urban settings; and rapid evolutionary change due to urbanization. We conclude that 1) urbanization can disrupt and alter zoochory processes; and 2) successful zoochory can, in turn, alleviate or worsen the challenges to ecosystem dynamics originating from increased urbanization. The dynamic urban seed dispersal networks are emerging as useful models for the adaptability of seed dispersal communities. Their study can also shed light on eco-evolutionary processes under anthropogenic selective pressures, including species interactions. Finally, urban zoochory processes are critical to the functioning of urban ecosystems and as such, constitute an important ecosystem service with management implications. We propose directions for further research into urban zoochory processes to ensure the maintenance of ecosystem dynamics as urbanization continues.

Evaluating the structure of commensalistic epiphyte–phorophyte networks: a comparative perspective of biotic interactions

Epiphytic vascular plants comprise an essential part of the tropical flora and are a key component for ecosystem functioning. Some recent studies have used a network approach to investigate the interaction of epiphytes with host phorophytes at the community level. However, knowledge on commensalistic epiphyte–phorophyte network structure still lags behind with regard to other biotic interaction networks. Our goal was to provide a more complete overall perspective on commensalistic epiphyte–phorophyte interaction and its placement with respect to other better studied mutualistic interactions. We hypothesized that the intensity of the fitness effect of the different types of biotic interactions would determine the degree of specialization of the interacting organisms. Thus, commensalistic epiphyte–phorophyte interactions would have lower specialization than mutualistic interactions. We compiled and analysed the structural properties (nestedness, network specialization and modularity) of 12 commensalistic epiphyte–phorophyte networks and compared them with the same metrics to 11 ant–myrmecophyte, 86 pollination and 13 seed dispersal mutualistic networks. Epiphyte–phorophyte networks were nested and modular with regard to the corresponding null models and had greater nestedness than mutualistic networks, whereas specialization and modularity were significantly lower. Commensalistic epiphyte–phorophyte networks of interactions are both nested and modular, and hence, are structured in a similar way to most other types of networks that involve co-evolutionary interactions. Nevertheless, the nature and intensity of the ecological processes involved in the generation of these patterns is likely to differ. The lower values of modularity in commensalistic epiphyte–phorophyte networks are probably due to the low levels of specialization and the lack of co-evolutionary processes between the interacting partners.

Identifying ‘firebreaks’ to fragment dispersal networks of a marine parasite

Marine ecosystems are beset by disease outbreaks, and efficient strategies to control dispersal of pathogens are scarce. We tested whether introducing no-farming areas or ‘firebreaks’ could disconnect dispersal networks of a parasitic disease affecting the world’s largest marine fish farming industry (∼1000 farms). Larval salmon lice (Lepeophtheirus salmonis) are released from and transported among salmon farms by ocean currents, creating inter-farm networks of louse dispersal. We used a state-of-the-art biophysical model to predict louse movement along the Norwegian coastline and network analysis to identify firebreaks to dispersal. At least one firebreak that fragmented the network into two large unconnected groups of farms was identified for all seasons. During spring, when wild salmon migrate out into the ocean, and louse levels per fish at farms must be minimised, two effective firebreaks were created by removing 13 and 21 farms (1.3% and 2.2% of all farms in the system) at ∼61°N and 67°N, respectively. We have demonstrated that dispersal models coupled with network analysis can identify no-farming zones that fragment dispersal networks. Reduced dispersal pathways should lower infection pressure at farms, slow the evolution of resistance to parasite control measures, and alleviate infection pressure on wild salmon populations.

Local drivers of the structure of a tropical bird-seed dispersal network.

One of the major challenges in ecology is to understand the relative importance of neutral- and niche-based processes structuring species interactions within communities. The concept of neutral-based processes posits that network structure is a result of interactions between species based on their abundance. On the other hand, niche-based processes presume that network structure is shaped by constraints to interactions. Here, we evaluated the relative importance of neutral-based process, represented by species' abundance (A) and fruit production (F) models, and niche-based process, represented by spatial overlap (S), temporal overlap (T) and morphological barrier (M) models, in shaping the structure of a bird-seed dispersal network from the Brazilian Atlantic Forest. We evaluated the ability of each model, singly or in combination, to predict the general structure [represented by connectance, nestedness (NODF), weight nestedness (WNODF), interaction evenness and complementary specialization] and microstructure of the network (i.e., the frequency of pairwise interactions). Only nestedness (both NODF and WNODF) was predicted by at least one model. NODF and WNODF were predicted by a neutral-based process (A), by a combination of niche-based processes (ST and STM) and by both neutral- and niche-based processes (AM). NODF was also predicted by F and FM model. Regarding microstructure, temporal overlap (T) was the most parsimonious model able to predict it. Our findings reveal that a combination of neutral- and niche-based processes is a good predictor of the general structure (NODF and WNODF) of the bird-seed dispersal network and a niche-based process is the best predictor of the network's microstructure.

HML-IDS: A Hybrid-Multilevel Anomaly Prediction Approach for Intrusion Detection in SCADA Systems

Critical infrastructures, e.g., electricity generation and dispersal networks, chemical processing plants, and gas distribution, are governed and monitored by supervisory control and data acquisition systems (SCADA). Detecting intrusion is a prevalent area of study for numerous years, and several intrusion detection systems have been suggested in the literature for cyber-physical systems and industrial control system (ICS). In recent years, the viruses seismic net, duqu, and flame against ICS attacks have caused tremendous damage to nuclear facilities and critical infrastructure in some countries. These intensified attacks have sounded the alarm for the security of the ICS in many countries. The challenge in constructing an intrusion detection framework is to deal with unbalanced intrusion datasets, i.e. when one class is signified by a lesser amount of instances (minority class). To this end, we outline an approach to deal with this issue and propose an anomaly detection method for the ICS. Our proposed approach uses a hybrid model that takes advantage of the anticipated and consistent nature of communication patterns that occur among ground devices in ICS setups. First, we applied some preprocessing techniques to standardize and scale the data. Second, the dimensionality reduction algorithms are applied to improve the process of anomaly detection. Third, we employed an edited nearest-neighbor rule algorithm to balance the dataset. Fourth, by using the Bloom filter, a signature database is created by noting the system for a specific period lacking the occurrence of abnormalities. Finally, to detect new attacks, we combined our package contents-level detection with another instance-based learner to make a hybrid method for anomaly detection. The experimental results with a real large-scale dataset generated from a gas pipeline SCADA system show that the proposed approach HML-IDS outperforms the benchmark models with an accuracy rate of 97%.

A Geographic Network Automata Approach for Modeling Dynamic Ecological Systems

Landscape connectivity networks are composed of nodes representing georeferenced habitat patches that link together based on a species’ maximum dispersal distance. These static representations cannot capture the complexity in species dispersal where the network of habitat patch nodes changes structure over time as a function of local dispersal dynamics. Therefore, the objective of this study is to integrate geographic information, complexity, and network science to propose a novel Geographic Network Automata (GNA) modeling approach for the simulation of dynamic spatial ecological networks. The proposed GNA modeling approach is applied to the emerald ash borer (EAB) forest insect infestation using geospatial data sets from Michigan, U.S.A. and simulates the evolution of the EAB spatiotemporal dispersal network structures across a large regional scale. The GNA model calibration and sensitivity analysis are performed. The simulated spatial network structures are quantified using graph theory measures. Results indicate that the spatial distribution of habitat patch nodes across the landscape in combination with EAB dispersal processes generate a highly connected small‐world dispersal network that is robust to node removal. The presented GNA model framework is general and flexible so that different types of geospatial phenomena can be modeled, providing valuable insights for management and decision‐making.

Loss of Generalist Plant Species and Functional Diversity Decreases the Robustness of a Seed Dispersal Network

SummaryUnderstanding cascading effects of species loss is a major challenge for ecologists. Traditionally, the robustness of ecological networks has been evaluated based on simulation studies where primary extinctions occur at random or as a function of species specialization, ignoring other important biological factors. Here, we estimate the robustness of a seed dispersal network from a grassland–forest mosaic in southern Brazil, simulating distinct scenarios of woody plant species extinction, including scenarios where species are eliminated based on their evolutionary and functional distinctiveness. Our results suggest that the network is more robust when species are eliminated based on their evolutionary uniqueness, followed by random extinctions, the extinction of the most specialist species, functional distinctiveness and, at last, when the most generalist species are sequentially eliminated. Our results provide important information for grassland–forest mosaic management, as they indicate that loss of generalist species and functional diversity makes the system more likely to collapse.

Frugivore biodiversity and complementarity in interaction networks enhance landscape‐scale seed dispersal function

Abstract Animal biodiversity matters for the provision of ecosystem functions derived from trophic activity. However, the mechanisms underlying this pattern remain elusive since animal abundance and diversity, which are the components commonly used for representing biodiversity, provide poor information about ecological complementarity in species assemblages. An approach based on species interaction networks may overcome this constraint. Here, we relate frugivore biodiversity and frugivore–plant network structure with landscape‐scale seed dispersal function. We sampled, for two years, and at fourteen plots with variable assemblages of frugivores and plants in the Cantabrian Range (N Spain), data on the abundance and diversity of frugivorous birds, the consumption of fleshy fruits of woody plants and the landscape‐scale patterns of avian seed deposition. As a measure of interaction complementarity in seed dispersal networks, we estimated the degree to which frugivore and plant species specialize in their interacting partners. Specialization varied strongly across the seed dispersal networks of the different plots, being higher in networks harbouring smaller bird species that dispersed mostly small‐fruited plants, and also in networks with late‐ripening, dominant fruiting species dispersed mostly by wintering birds. Bird abundance markedly affected seed deposition. Plots harbouring more birds received a higher density of dispersed seeds and showed higher probabilities of seed arrival and seed deposition in open microhabitats. Bird diversity also had a positive effect on the density of dispersed seed and, to a lesser extent, seed arrival probability. Independently of frugivore abundance and diversity, the density of dispersed seeds increased in plots where seed dispersal networks showed a higher degree of specialization. This study considers the structure of interaction networks to re‐address the relationship between biodiversity and ecosystem functionality, evidencing that specialization in frugivore–plant networks drives the large‐scale process of seed dispersal. These results encourage the consideration of interaction complementarity as an underlying mechanism linking animal biodiversity and trophic‐related functions.

Mapping the resilience of chemosynthetic communities in hydrothermal vent fields

Hydrothermal vent fields are vulnerable to natural disturbances, such as volcanic activity, and are currently being considered as targets for mineral mining. Local vent communities are linked by pelagic larval dispersal and form regional metacommunities, nested within a number of biogeographic provinces. Larval supply depends on the connectivity of the dispersal networks, and affects recoverability of communities from disturbances. However, it is unclear how the dispersal networks contribute to recoverability of local communities. Here, we integrated a population dynamics model and estimation of large scale dispersal networks. By simulating disturbances to vent fields, we mapped recoverability of communities in 131 hydrothermal vent fields in the western Pacific Ocean. Our analysis showed substantial variation in recovery time due to variation in regional connectivity between known vent fields, and was not qualitatively affected by potential larval recruitment from unknown vent fields. In certain cases, simultaneous disturbance of a series of vent fields either delayed or wholly prevented recovery. Our approach is applicable to a dispersal network estimated from genetic diversity. Our method not only reveals distribution of recoverability of chemosynthetic communities in hydrothermal vent fields, but is also a practical tool for planning conservation strategies.

Rewiring of experimentally disturbed seed dispersal networks might lead to unexpected network configurations

The consequences of species extinctions in ecological communities may be buffered through the rearrangement (rewiring) of the interactions between the remaining species. The structural and functional consequences of such extinctions can be explored by means of computer simulations that try to predict secondary extinctions and the degradation of ecosystem services. However, to improve the accuracy of these simulations, it is pivotal to evaluate their performance in predicting changes observed in natural communities. In this study, we first described the avian seed dispersal networks in 17 sites throughout Portugal, and found that blackberry (Rubus ulmifolius) was the most dispersed species in 13 out of the 17 sites. Second, we performed a manipulative experiment to evaluate the effect of removing the most dispersed plant species and compared the observed outcome in the structure of the network with computer simulations with and without rewiring. Observed changes were consistent with some rapid network rewiring, with dispersers shifting to alternative fruit species. Although the observed network topology after the experimental removal was not accurately predicted, the extinction simulation with rewiring performed considerably better than that without rewiring. Individual species roles were even harder to predict than emergent network properties on both types of models. We show that incorporating rewiring rules can considerably increase the accuracy of species extinction models, however, the functional consequences of losing important resources might not be easily anticipated, and rewiring might occur in unexpected directions.

Introduction of mammalian seed predators and the loss of an endemic flightless bird impair seed dispersal of the New Zealand tree Elaeocarpus dentatus.

Understanding the mutualistic services provided by species is critical when considering both the consequences of their loss or the benefits of their reintroduction. Like many other Pacific islands, New Zealand seed dispersal networks have been changed by both significant losses of large frugivorous birds and the introduction of invasive mammals. These changes are particularly concerning when important dispersers remain unidentified. We tested the impact of frugivore declines and invasive seed predators on seed dispersal for an endemic tree, hinau Elaeocarpus dentatus, by comparing seed dispersal and predation rates on the mainland of New Zealand with offshore sanctuary islands with higher bird and lower mammal numbers. We used cameras and seed traps to measure predation and dispersal from the ground and canopy, respectively. We found that canopy fruit handling rates (an index of dispersal quantity) were poor even on island sanctuaries (only 14% of seeds captured below parent trees on islands had passed through a bird), which suggests that hinau may be adapted for ground‐based dispersal by flightless birds. Ground‐based dispersal of hinau was low on the New Zealand mainland compared to sanctuary islands (4% of seeds dispersed on the mainland vs. 76% dispersed on islands), due to low frugivore numbers. A flightless endemic rail (Gallirallus australis) conducted the majority of ground‐based fruit removal on islands. Despite being threatened, this rail is controversial in restoration projects because of its predatory impacts on native fauna. Our study demonstrates the importance of testing which species perform important mutualistic services, rather than simply relying on logical assumptions.

Moving from frugivory to seed dispersal: Incorporating the functional outcomes of interactions in plant-frugivore networks.

There is growing interest in understanding the functional outcomes of species interactions in ecological networks. For many mutualistic networks, including pollination and seed dispersal networks, interactions are generally sampled by recording animal foraging visits to plants. However, these visits may not reflect actual pollination or seed dispersal events, despite these typically being the ecological processes of interest.Frugivorous animals can act as seed dispersers, by swallowing entire fruits and dispersing their seeds, or as pulp peckers or seed predators, by pecking fruits to consume pieces of pulp or seeds. These processes have opposing consequences for plant reproductive success. Therefore, equating visitation with seed dispersal could lead to biased inferences about the ecology, evolution and conservation of seed dispersal mutualisms.Here, we use natural history information on the functional outcomes of pairwise bird–plant interactions to examine changes in the structure of seven European plant–frugivore visitation networks after non‐mutualistic interactions (pulp pecking and seed predation) have been removed. Following existing knowledge of the contrasting structures of mutualistic and antagonistic networks, we hypothesized a number of changes following interaction removal, such as increased nestedness and lower specialization.Non‐mutualistic interactions with pulp peckers and seed predators occurred in all seven networks, accounting for 21%–48% of all interactions and 6%–24% of total interaction frequency. When non‐mutualistic interactions were removed, there were significant increases in network‐level metrics such as connectance and nestedness, while robustness decreased. These changes were generally small, homogenous and driven by decreases in network size. Conversely, changes in species‐level metrics were more variable and sometimes large, with significant decreases in plant degree, interaction frequency, specialization and resilience to animal extinctions and significant increases in frugivore species strength.Visitation data can overestimate the actual frequency of seed dispersal services in plant–frugivore networks. We show here that incorporating natural history information on the functions of species interactions can bring us closer to understanding the processes and functions operating in ecological communities. Our categorical approach lays the foundation for future work quantifying functional interaction outcomes along a mutualism–antagonism continuum, as documented in other frugivore faunas.

Functional Resistance to Recurrent Spatially Heterogeneous Disturbances Is Facilitated by Increased Activity of Surviving Bacteria in a Virtual Ecosystem.

Bacterial degradation of organic compounds is an important ecosystem function with relevance to, e.g., the cycling of elements or the degradation of organic contaminants. It remains an open question, however, to which extent ecosystems are able to maintain such biodegradation function under recurrent disturbances (functional resistance) and how this is related to the bacterial biomass abundance. In this paper, we use a numerical simulation approach to systematically analyze the dynamic response of a microbial population to recurrent disturbances of different spatial distribution. The spatially explicit model considers microbial degradation, growth, dispersal, and spatial networks that facilitate bacterial dispersal mimicking effects of mycelial networks in nature. We find: (i) There is a certain capacity for high resistance of biodegradation performance to recurrent disturbances. (ii) If this resistance capacity is exceeded, spatial zones of different biodegradation performance develop, ranging from no or reduced to even increased performance. (iii) Bacterial biomass and biodegradation dynamics respond inversely to the spatial fragmentation of disturbances: overall biodegradation performance improves with increasing fragmentation, but bacterial biomass declines. (iv) Bacterial dispersal networks can enhance functional resistance against recurrent disturbances, mainly by reactivating zones in the core of disturbed areas, even though this leads to an overall reduction of bacterial biomass.

Revealing hidden insect-fungus interactions; moderately specialized, modular and anti-nested detritivore networks.

Ecological networks are composed of interacting communities that influence ecosystem structure and function. Fungi are the driving force for ecosystem processes such as decomposition and carbon sequestration in terrestrial habitats, and are strongly influenced by interactions with invertebrates. Yet, interactions in detritivore communities have rarely been considered from a network perspective. In the present study, we analyse the interaction networks between three functional guilds of fungi and insects sampled from dead wood. Using DNA metabarcoding to identify fungi, we reveal a diversity of interactions differing in specificity in the detritivore networks, involving three guilds of fungi. Plant pathogenic fungi were relatively unspecialized in their interactions with insects inhabiting dead wood, while interactions between the insects and wood-decay fungi exhibited the highest degree of specialization, which was similar to estimates for animal-mediated seed dispersal networks in previous studies. The low degree of specialization for insect symbiont fungi was unexpected. In general, the pooled insect-fungus networks were significantly more specialized, more modular and less nested than randomized networks. Thus, the detritivore networks had an unusual anti-nested structure. Future studies might corroborate whether this is a common aspect of networks based on interactions with fungi, possibly owing to their often intense competition for substrate.

Local extinctions of obligate frugivores and patch size reduction disrupt the structure of seed dispersal networks

A central problem in ecology is to understand how human impacts affect plant–animal interactions that lead to effective seed dispersal services for plant communities. Seed dispersal services are the outcome of plant–frugivore interactions that often form local networks of interacting species. Recent work has shown that some frugivorous bird species are more critical to network organization than others. Here, we explore how patch size and the potential local extinctions of obligate frugivorous birds affect the reorganization of seed dispersal networks. We examined the structure of 20 empirical seed dispersal networks documented across tropical avian assemblages occupying widely variable habitat patch sizes, a surrogate of the amount of remaining habitat. Networks within small forest patches consistently supported both lower plant and bird species richness. Forest patch size was positively associated with nestedness, indicating that reductions in patch size disrupted the nested organization of seed dispersal networks. Obligate frugivores, especially large‐bodied species, were almost entirely absent from small forest patches. Analysis at the species level showed that obligate frugivores formed the core of interacting species, connecting species within a given seed dispersal network. Our combined results revealed that patch size reduction erodes frugivorous bird diversity, thereby affecting the integrity of seed dispersal networks. We highlight the importance of conserving large forest patches to maintain tropical forest functionality.

Graph‐theoretic method on the periodicity of multipatch dispersal predator‐prey system with Holling type‐II functional response

We study the periodicity of multipatch dispersal predator‐prey system with Holling type‐II functional response in this paper. By providing a new method, we overcome the difficulty to get the priori bounds estimation of unknown solutions of operator equation Lu=λNu. Graph theory with coincidence degree theory is used, and a sufficient criterion for the periodicity of the system is obtained. The criterion presented in this paper is closely related with topological structure of dispersal network and can be verified easily. Finally, a numerical example is also provided to verify the effectiveness of theoretical results.

Multilayer networks reveal the spatial structure of seed-dispersal interactions across the Great Rift landscapes

Species interaction networks are traditionally explored as discrete entities with well-defined spatial borders, an oversimplification likely impairing their applicability. Using a multilayer network approach, explicitly accounting for inter-habitat connectivity, we investigate the spatial structure of seed–dispersal networks across the Gorongosa National Park, Mozambique. We show that the overall seed–dispersal network is composed by spatially explicit communities of dispersers spanning across habitats, functionally linking the landscape mosaic. Inter-habitat connectivity determines spatial structure, which cannot be accurately described with standard monolayer approaches either splitting or merging habitats. Multilayer modularity cannot be predicted by null models randomizing either interactions within each habitat or those linking habitats; however, as habitat connectivity increases, random processes become more important for overall structure. The importance of dispersers for the overall network structure is captured by multilayer versatility but not by standard metrics. Highly versatile species disperse many plant species across multiple habitats, being critical to landscape functional cohesion.