Structure Of Ecological Networks Research Articles

Diagnosis of the fragmentation of urban ecological network structure and its social-ecological responses.

The fragmentation of ecological network structures has become a common problem faced by cities. By establishing the urban ecological network under a specific socio-ecological system framework, we aimed to propose a quantitative index to diagnose the fragmentation of the network structure, and to construct detection model to explore the driving factors and mechanism of the network fragmentation. Using Shenzhen City as an example, we used the Floyd-Prim algorithm to generate the skeleton structure of the ecological network and construct a density discontinuity index to diagnose network fragmentation. Combined with the ecological network scenario, social-ecological system framework and a two-layer indicator system were constructed. The detection models were then established to explore the drivers of network disruption and their mode of impact. The models show that the average degree of network fragmentation in Shenzhen was 0.13, and the density of about 85% of corridor discontinuities was greater than 0.01, reflecting the serious state of structural fragmentation. Corridors with more severe structural fragmentation have poorer social-ecological coordination. The fragmentation in Shenzhen was mainly affected by the activities of actors (A) at the microlevel and the resource system (RS) at the macrolevel. The methods and the framework of socio-ecosystem analysis proposed in this paper can reveal the driving factors and influence modes of network fragmentation, providing decision-making reference for ecological restoration practice in urbanized areas.

Australia's recently established predators restore complexity to food webs simplified by extinction.

Since prehistory, humans have altered the composition of ecosystems by causing extinctions and introducing species. However, our understanding of how waves of species extinctions and introductions influence the structure and function of ecological networks through time remains piecemeal. Here, focusing on Australia, which has experienced many extinctions and introductions since the Late Pleistocene, we compared the functional trait composition of Late Pleistocene (130,00-115,000 years before present [ybp]), Holocene (11,700-3,000 ybp), and current Australian mammalian predator assemblages (≥70% vertebrate meat consumption; ≥1kg adult body mass). We then constructed food webs for each period based on estimated prey body mass preferences. We found that introduced predators are functionally distinct from extinct Australian predators, but they rewire food webs toward a state that closely resembles the Late Pleistocene, prior to the megafauna extinctions. Both Late Pleistocene and current-day food webs consist of an apex predator and three smaller predators. This leads to food web networks with a similar total number of links, link densities, and compartmentalizations. However, this similarity depends on the presence of dingoes: in their absence, food webs become simplified and reminiscent of those following the Late Pleistocene extinctions. Our results suggest that recently established predators, even those implicated in species extinctions and declines, can restore complexity to food webs simplified by extinction.

Restoration of the ecological network structure based on the spatiotemporal changes of the wintering Grus japonensis habitat in the Yancheng coastal area

As an Asian endemic species, Grus japonensis (G. japonensis) reproduction and survival rely on natural wetland resources. G. japonensis is adept at long-distance flight, thereby displaying distinct network structural characteristics in its utilization of habitat within its range. Therefore, scientific restoration and management of the ecological network (ENs) are urgently needed. On the basis of the data of G. japonensis and environmental data, this study used the MaxEnt model, stepping-stone theory, and circuit models to analyze the spatiotemporal changes in the ENs structure of G. japonensis habitat. The primary factors influencing the habitat suitability of G. japonensis was the distance to Phragmites australis (P. australis) community. The area of ecological source areas decreased from 56,528.59 hm2 in 1987 to 14,040.20 hm2 in 2021, with the distribution range contracting from Beihuan (BH), Nanhuan (NH), Hexin (HX) and Tiaozini (TZN) to Hexin (HX). Between 1987 and 2007, there were dense ecological corridors along the coastal areas. However, by 2021, only BH and HX had dense ecological corridors between them. The node centrality of HX decreased from 900.78 in 1987 to 264.64 in 2021, with the most significant decrease between 2007 and 2021. On this basis, the expanded habitat area, the stepping stone area in 2021 and the ecological source area of 2007 with low development intensity were taken as restoration areas. The restoration areas were classified into two types based on their distribution: landing nodes and expansion nodes. The addition of landing nodes enhanced the overall stability of the ENs, resulting in an increase in the centrality of nodes from 264.64 to 398.08. Finally, an optimization and restoration framework for the habitat network based on identifying priority restoration areas, land use type transformation, and enhancing ENs stability for habitat restoration was proposed.

Multiple stressors drive multitrophic biodiversity and ecological network dynamics in a shrinking sandy lake

Stressors endanger lake ecosystem biodiversity and networks, especially in sandy lakes of arid/semiarid regions, where impacts are poorly understood. Here, we investigate the changes in multitrophic biodiversity and ecological networks under increasing stress (temperature, nutrients, lake area) by using sedimentary DNA from a shrinking sandy lake in China over nearly 100 years. With increasing stress, species richness and stability increased, whereas species turnover decreased. Species synchronism decreased at high-trophic levels but increased at low-trophic levels. Empirical dynamic modeling showed network connectance and strength of species interactions decreased–increased–decreased over time, signaling a potential adaption–resistance–degradation change in ecosystem responses with increasing stress. Models also indicated network structure primarily depended on direct effects of nutrients and temperature under low/medium stress and on a diversity-mediated pathway under high stress. Thus, maintaining ecological network structure complexity and integrity in lake ecosystems is essential to mitigate the effects of multiple stresses.

Effects of dietary restriction and one-carbon metabolite supplementation during the first 63 days of gestation on the maternal gut, vaginal, and blood microbiota in cattle

BackgroundMaternal diet quality and quantity have significant impacts on both maternal and fetal health and development. The composition and function of the maternal gut microbiome is also significantly influenced by diet; however, little is known about the impact of gestational nutrient restriction on the bovine maternal microbiome during early gestation, which is a critical stage for maternal microbiome-mediated fetal programming to take place. The objective of the present study was to evaluate the impacts of diet restriction and one-carbon metabolite (OCM) supplementation during early gestation on maternal ruminal, vaginal, and blood microbiota in cattle. Thirty-three beef heifers (approx. 14 months old) were used in a 2 × 2 factorial experiment with main factors of target gain (control [CON]; targeted 0.45 kg/d gain vs restricted [RES]; targeted − 0.23 kg/d gain), and OCM supplementation (+ OCM vs − OCM; n = 8/treatment; except n = 9 for RES–OCM). Heifers were individually fed, starting treatment at breeding (d 0) and concluding at d 63 of gestation. Ruminal fluid and vaginal swabs were collected on d − 2, d 35, and d 63 (at necropsy) and whole blood was collected on d 63 (necropsy). Bacterial microbiota was assessed using 16S rRNA gene (V3–V4) sequencing.ResultsOverall ruminal microbiota structure was affected by gain, OCM, time, and their interactions. The RES heifers had greater microbial richness (observed ASVs) but neither Shannon nor Inverse Simpson diversity was significantly influenced by gain or OCM supplementation; however, on d 63, 34 bacterial genera showed differential abundance in the ruminal fluid, with 25 genera enriched in RES heifers as compared to CON heifers. In addition, the overall interaction network structure of the ruminal microbiota changed due to diet restriction. The vaginal microbiota community structure was influenced by gain and time. Overall microbial richness and diversity of the vaginal microbiota steadily increased as pregnancy progressed. The vaginal ecological network structure was distinctive between RES and CON heifers with genera-genera interactions being intensified in RES heifers. A relatively diverse bacterial community was detected in blood samples, and the composition of the blood microbiota differed from that of ruminal and vaginal microbiota.ConclusionRestricted dietary intake during early gestation induced significant alterations in the ruminal microbiota which also extended to the vaginal microbiota. The composition of these two microbial communities was largely unaffected by OCM supplementation. Blood associated microbiota was largely distinctive from the ruminal and vaginal microbiota.

Multi-generational dispersal and dynamic patch occupancy reveals spatial and temporal stability of seascapes

The success of non-native species (NNS) invasions depends on patterns of dispersal and connectivity, which underpin genetic diversity, population establishment and growth. In the marine environment, both global environmental change and increasing anthropogenic activity can alter hydrodynamic patterns, leading to significant inter-annual variability in dispersal pathways. Despite this, multi-generational dispersal is rarely explicitly considered in attempts to understand NNS spread or in the design of management interventions. Here, we present a novel approach to quantifying species spread that considers range expansion and network formation across time using the non-native Pacific oyster, Magallana gigas (Thunberg 1793), as a model. We combined biophysical modelling, dynamic patch occupancy models, consideration of environmental factors, and graph network theory to model multi-generational dispersal in northwest Europe over 13 generations. Results revealed that M. gigas has a capacity for rapid range expansion through the creation of an ecological network of dispersal pathways that remains stable through time. Maximum network size was achieved in four generations, after which connectivity patterns remained temporally stable. Multi-generational connectivity could therefore be divided into two periods: network growth (2000−2003) and network stability (2004–2012). Our study is the first to examine how dispersal trajectories affect the temporal stability of ecological networks across biogeographic scales, and provides an approach for the assignment of site-based prioritisation of non-native species management at different stages of the invasion timeline. More broadly, the framework we present can be applied to other fields (e.g. Marine Protected Area design, management of threatened species and species range expansion due to climate change) as a means of characterising and defining ecological network structure, functioning and stability.

Combining critical transition indicator to compare the stable structure of epiphyte–host networks

Networks have been widely used to describe a range of biotic interactions in ecosystems; topological indicators of ecological networks provide systematic way to characterize patterns of different interacting systems. However, it is hampered by sampling bias and detecting the true structures to compare the stability of ecological communities. In this context, we aimed to employ innovative approach of identifying critical transition indicator to compare stable network structure by simulating dynamics of network assembly. Four epiphyte–host networks were compiled, including two groups (epiphytic bryophyte and epiphytic vascular plant) of tropical rainforest (TRF) and subtropical forest (STF). The dynamics of three structure indictors, i.e. connectance, nestedness and modularity were simulated to explore what changes occurred as sampling effort increases. The critical transition indicator was detected to compare the structure of four networks at a stable state. Meanwhile, the variation dynamics of host size and epiphyte richness were fitted to analyze the underlying processes shaping the stable network structure. Using a dynamic simulation, the network structures showed the critical transition to stable state when sampling size approximated 30 hosts for epiphytic bryophytes and 100 hosts for epiphytic vascular plants. After critical transition, connectance and nestedness were higher in the STF than in the TRF. In contrast, modularity was higher in the TRF than in the STF. The coefficient of variations (CV) of host size and epiphyte richness tended to be stable at the same critical transition point; the distribution of host size and epiphyte richness could be the fundamental factors for the assembly of stable epiphyte–host network. Our study emphasized the importance of considering sampling effort while evaluating the network structure. Combining critical transition indicator with structure indicator dynamics could be a powerful method to compare the stable structure of different ecological networks.

Soil phosphorus cycling microbial functional genes of monoculture and mixed plantations of native tree species in subtropical China.

Transforming coniferous plantation into broadleaved or mixed broadleaved-coniferous plantations is the tendency of forest management strategies in subtropical China. However, the effects of this conversion on soil phosphorus (P) cycling microbial functional genes are still unknown. Soil samples were collected from 0-20, 20-40, and 40-60 cm (topsoil, middle layer, and subsoil, respectively) under coniferous Pinus massoniana (PM), broadleaved Erythrophleum fordii (EF), and their mixed (PM/EF) plantation in subtropical China. Used metagenomic sequencing to examine the alterations of relative abundances and molecular ecological network structure of soil P-cycling functional genes after the conversion of plantations. The composition of P-cycling genes in the topsoil of PM stand was significantly different from that of PM/EF and EF stands (p < 0.05), and total phosphorus (TP) was the main factor causing this difference. After transforming PM plantation into EF plantation, the relative abundances of P solubilization and mineralization genes significantly increased in the topsoil and middle layer with the decrease of soil TP content. The abundances of P-starvation response regulation genes also significantly increased in the subsoil (p < 0.05), which may have been influenced by soil organic carbon (SOC). The dominant genes in all soil layers under three plantations were phoR, glpP, gcd, ppk, and ppx. Transforming PM into EF plantation apparently increased gcd abundance in the topsoil (p < 0.05), with TP and NO3 --N being the main influencing factors. After transforming PM into PM/EF plantations, the molecular ecological network structure of P-cycling genes was more complex; moreover, the key genes in the network were modified with the transformation of PM plantation. Transforming PM into EF plantation mainly improved the phosphate solubilizing potential of microorganisms at topsoil, while transforming PM into PM/EF plantation may have enhanced structural stability of microbial P-cycling genes react to environmental changes.

Construction of Ecological Security Patterns and Evaluation of Ecological Network Stability under Multi-Scenario Simulation: A Case Study in Desert–Oasis Area of the Yellow River Basin, China

Land use change has a significant impact on the sustainability of ecosystems, and ecological security patterns (ESPs) can improve environmental quality through spatial planning. This study explored a multi-scenario ESP framework by integrating future land use simulation (FLUS) and minimum cumulative resistance (MCR) for urban agglomeration along the Yellow River Basin (YRB) in Ningxia. The research involved simulating land use change in 2035 under four development scenarios, identifying ecological security networks, and evaluating network stability for each scenario. The study revealed that the ecological sources under different development scenarios, including a natural development scenario (NDS), an economic development scenario (EDS), a food security scenario (FSS), and an ecological protection scenario (EPS), were 834.82 km2, 715.46 km2, 785.56 km2, and 1091.43 km2, respectively. The overall connectivity values (OG) for these scenarios were 0.351, 0.466, 0.334, and 0.520, respectively. It was found that under an EPS, the ESPs had the largest area of ecological sources and the most stable ecological network structure, which can effectively protect natural habitats. This study provides a valuable method for identifying ESPs that can respond to diversity and the uncertainty of future development. It can assist decision-makers in enhancing the ecological quality of the study area while considering various development scenarios.

Networking nutrients: How nutrition determines the structure of ecological networks.

Nutrients can shape ecological interactions but remain poorly integrated into ecological networks. Concepts such as nutrient-specific foraging nevertheless have the potential to expose the mechanisms structuring complex ecological systems. Nutrients also present an opportunity to predict dynamic processes, such as interaction rewiring and extinction cascades, and increase the accuracy of network analyses. Here, we propose the concept of nutritional networks. By integrating nutritional data into ecological networks, we envisage significant advances to our understanding of ecological processes from individual to ecosystem scales. We show that networks can be constructed with nutritional data to illuminate how nutrients structure ecological interactions in natural systems through an empirical example. Throughout, we identify fundamental ecological hypotheses that can be explored in a nutritional network context, alongside methods for resolving those networks. Nutrients influence the structure and complexity of ecological networks through mechanistic processes and concepts including nutritional niche differentiation, functional responses, landscape diversity, ecological invasions and ecosystem robustness. Future research on ecological networks should consider nutrients when investigating the drivers of network structure and function.

Forest loss and habitat changes reduce hummingbird functional diversity and the specialization of their interactions with plants in the tropical Andes

The expansion of agricultural landscapes is one of the main drivers of biodiversity loss around the world; the environmental gradients resulting from these landscape changes, however, allow an assessment of how biodiversity responds to environmental change. Functional diversity and mutualistic interactions between plants and animals represent an important aspect of biodiversity. In particular, the interactions between hummingbirds and plants stand out for their morphological specialization. Here, we evaluated how changes in landscape attributes affect the functional diversity and hummingbird-plant interaction networks in the coffee-growing region of the Colombian Andes. We described the functional diversity of hummingbirds and their interaction networks with plants in circular plots with a diameter of 50 m located in forests and coffee agroecosystems distributed along a landscape transformation gradient. We found that network specialization in forests is positively related to forest coverage of the landscape, while the relationship with landscape diversity and heterogeneity was weak. In contrast, we found no relationship between landscape variables and network specialization in coffee agroecosystems where the networks are less specialized and less modular compared to forests. A structural equation model (SEM) showed that hummingbird functional diversity had a significant relationship to landscape structure, while the specialization of hummingbird-plant networks was mainly affected by the amount of forest in the landscape. Although no significant direct relationship was found between hummingbird functional diversity and network specialization, SEMs show that, when considering a mediating role of functional diversity, the specialization R2 coefficient increased. Based on our results, we suggest that changes in the diversity and structure of ecological networks were a consequence of the impacts of human intervention on landscapes and natural habitats.

Ecosystem engineers shape ecological network structure and stability: A framework and literature review

Abstract Ecosystem engineering is a ubiquitous process where species influence the physical environment and thereby structure ecological communities. However, there has been little effort to synthesize or predict how ecosystem engineering may impact the structure and stability of interaction networks. To assess current scientific understanding of ecosystem engineering impacts via habitat forming, habitat modification and bioturbation on interaction networks/food webs, we reviewed the literature covering marine, freshwater and terrestrial food webs, plant‐pollinator networks and theory. We provide a conceptual framework and identify three major pathways of engineering impact on networks through changes in resource availability and energy flow, habitat heterogeneity and environmental filtering. These three processes often work in concert and most studies report that engineering increases species richness. This is particularly marked for engineers that increase habitat heterogeneity and thereby the number of available niches. The response of network structure to ecosystem engineering varies, however some patterns emerge from this review. Engineered habitat heterogeneity leads to a higher number of links between species in the networks and increases link density. Connectance can be negatively or positively affected by ecosystem engineer impact, depending on the engineering pathway and the engineer impact of species richness. We discuss how ecosystem engineers can stabilize or destabilize communities through the changes in niche space, diversity, network structure and the dependency on the engineering impact. Theory and empirical evidence need to inform each other to better integrate ecosystem engineering and ecological networks. A mechanistic understanding how ecosystem engineering traits shape interactions networks and their stability will be important to predict species extinctions and can provide crucial information for conservation and ecosystem restoration. Read the free Plain Language Summary for this article on the Journal blog.

Understanding Trophic Interactions in a Warming World by Bridging Foraging Ecology and Biomechanics with Network Science.

Climate change will disrupt biological processes at every scale. Ecosystem functions and services vital to ecological resilience are set to shift, with consequences for how we manage land, natural resources, and food systems. Increasing temperatures cause morphological shifts, with concomitant implications for biomechanical performance metrics crucial to trophic interactions. Biomechanical performance, such as maximum bite force or running speed, determines the breadth of resources accessible to consumers, the outcome of interspecific interactions, and thus the structure of ecological networks. Climate change-induced impacts to ecosystem services and resilience are therefore on the horizon, mediated by disruptions of biomechanical performance and, consequently, trophic interactions across whole ecosystems. Here, we argue that there is an urgent need to investigate the complex interactions between climate change, biomechanical traits, and foraging ecology to help predict changes to ecological networks and ecosystem functioning. We discuss how these seemingly disparate disciplines can be connected through network science. Using an ant-plant network as an example, we illustrate how different data types could be integrated to investigate the interaction between warming, bite force, and trophic interactions, and discuss what such an integration will achieve. It is our hope that this integrative framework will help to identify a viable means to elucidate previously intractable impacts of climate change, with effective predictive potential to guide management and mitigation.

Optimization of ecological network function and structure by coupling spatial operators and biomimetic intelligent algorithm

Ecological networks (ENs) can maintain regional ecological security and reconcile the contradiction between development and conservation. Optimization of ENs is crucial for promoting sustainable development and human well-being. Although various valuable methods have been explored to optimize ENs, collaborative optimization research on the EN function and structure through a quantitative simulation at the patch level is yet to be conducted. This study integrated spatial function and structural operators into a multi-type ant colony optimization model and constructed a high-performance land-use conversion framework for EN optimization. Results showed that: (1) the optimized ecological source exhibits heightened functionality and improved connectivity, resulting in a more stable and rational network structure; (2) the proposed ecological nodes emergence mechanism prevents fragmentation of local ENs and improves the overall structural integrity and resilience; and (3) the introduction of graphics processing unit (GPU) parallelization improves the efficiency of the model at city level by 13.49 times, resolving the paradox between the computational efficiency of high-precision land-use simulation and the construction of large-scale ENs. This study provides methodological support for patch-level landscape planning and reference for formulating reasonable ecological restoration strategies.

Construction of ecological network in Qujing city based on MSPA and MCR models.

With the rapid advancement of urbanization and industrialization, ecological patches within cities and towns are fragmented and ecological corridors are cut off, regional ecological security is threatened and sustainable development is hindered. Building an ecological network that conforms to regional realities can connect fragmented patches, protect biodiversity and regional characteristics, and provide scientific reference for regional ecological protection and ecological network planning. By taking Qilin District, the main urban area of Qujing City as an example, and using geospatial data as the main data source, based on morphological spatial pattern analysis (MSPA) and minimum cumulative resistance (MCR), this study identified ecological source areas, extracted ecological corridors, and build & optimize ecological networks. (1) All landscape types are identified based on MSPA, the proportion of core area was the highest among all landscape types, which was 80.69%, combined with the connectivity evaluation, 14 important ecological source areas were selected. (2) 91 potential ecological corridors were extracted through MCR and gravity models, there were 16 important ones. (3) The network connectivity analysis method is used to calculate the α, β, and γ indexes of the ecological network before optimization, which were 2.36, 6.5, and 2.53, while after optimization, α, β and γ indices were 3.8, 9.5 and 3.5, respectively. The combined application of MSPA-MCR model and ecological network connectivity analysis evaluation is conducive to improving the structure and functionality of ecological network.

Telling mutualistic and antagonistic ecological networks apart by learning their multiscale structure

Abstract Characterizing and understanding the processes that shape the structure of ecological networks, which represent who interacts with whom in a community, has many implications in ecology, evolutionary biology and conservation. A highly debated question is whether and how the structure of a bipartite ecological network differs between antagonistic (e.g. herbivory) and mutualistic (e.g. pollination) interaction types. Here, we tackle this question by using a multiscale characterization of network structure, machine learning tools, and a large database of empirical and simulated bipartite networks. Contrary to previous studies focusing on global structural metrics, such as nestedness and modularity, which concluded that antagonistic and mutualistic networks cannot be told apart from only their structure, we find that they can be told apart by combining a meso‐scale characterization of their structure and supervised machine learning. Motif frequencies appear particularly informative, with an over‐representation of densely connected motifs in antagonistic networks and of motifs with asymmetrical specialization in mutualistic networks. These structural properties can be used to predict the type of interaction with relatively good confidence. Beyond this classical mutualism/antagonism dichotomy, we also find significant structural uniqueness linked to specific ecologies (e.g. pollination, parasitism). Our results clarify structural differences between antagonistic and mutualistic networks and suggest the investigation of the structural uniqueness of specific ecologies as a promising approach for characterizing interactions beyond the coarse antagonistic/mutualistic dichotomy.

Perspectives in modelling ecological interaction networks for sustainable ecosystem management

Abstract The concept of ecological interaction networks has been widely used in fundamental ecology in the last two decades and has progressively infused in a diverse array of applied studies. Classical studies represented species interactions as static interaction webs to identify generalities in the structure of ecological networks and understand the propagation of indirect effects of species on each other and the environment. More recent research demonstrates that ecological networks are emerging features of community and interaction processes. Understanding the determinants of interaction variability in space and time and its consequences for biodiversity dynamics and ecosystem functioning constitute current frontiers in ecological network science. Although these frontiers meet a variety of applied ecological questions, many network models have been developed without clear applied perspectives. We detail how we could build on them to advance three main topics. First, the spatial dimension of ecological networks has direct implications for the design of sustainable landscapes and fisheries, for agroecology and for lake management. Second, the temporal dimension of ecological networks provides important insights for projecting biodiversity changes and adapting human actions. Third, the interactions between the abiotic and biotic components of ecosystems constitute key drivers of biogeochemical cycles, thereby providing important levers for sustainable management. Synthesis and applications. Collaborative work between empirical and theoretical network ecologists could accelerate the delivery of realistic models to inform applied practices across disciplines.

The structure and robustness of ecological networks with two interaction types.

Until recently, most ecological network analyses investigating the effects of species' declines and extinctions have focused on a single type of interaction (e.g. feeding). In nature, however, diverse interactions co-occur, each of them forming a layer of a 'multilayer' network. Data including information on multiple interaction types has recently started to emerge, giving us the opportunity to have a first glance at possible commonalities in the structure of these networks. We studied the structural features of 44 tripartite ecological networks from the literature, each composed of two layers of interactions (e.g. herbivory and pollination), and investigated their robustness to species losses. Considering two interactions simultaneously, we found that the robustness of the whole community is a combination of the robustness of the two ecological networks composing it. The way in which the layers of interactions are connected to each other affects the interdependence of their robustness. In many networks, this interdependence is low, suggesting that restoration efforts would not automatically propagate through the whole community. Our results highlight the importance of considering multiple interactions simultaneously to better gauge the robustness of ecological communities to species loss and to more reliably identify key species that are important for the persistence of ecological communities.

Adaptive rewiring shapes structure and stability in a three-guild herbivore-plant-pollinator network

Animal species, encompassing both pollinators and herbivores, exhibit a preference for plants based on optimal foraging theory. Understanding the intricacies of these adaptive plant-animal interactions in the context of community assembly poses a main challenge in ecology. This study delves into the impact of adaptive interaction rewiring between species belonging to different guilds on the structure and stability of a 3-guild ecological network, incorporating both mutualistic and antagonistic interactions. Our findings reveal that adaptive rewiring results in sub-networks becoming more nested and compartmentalized. Furthermore, the rewiring of interactions uncovers a positive correlation between a plant’s generalism concerning both pollinators and herbivores. Additionally, there is a positive correlation between a plant’s degree centrality and its energy budget. Although network stability does not exhibit a clear relationship with non-random structures, it is primarily influenced by the balance of multiple interaction strengths. In summary, our results underscore the significance of adaptive interaction rewiring in shaping the structure of 3-guild networks. They emphasize the importance of considering the balance of multiple interactions for the stability of adaptive networks, providing valuable insights into the complex dynamics of ecological communities.

Assessment and optimization of urban ecological network resilience based on disturbance scenario simulations: A case study of Nanjing city

Urbanization has serious implications for the structure and function of ecological networks. Augmenting resilience offers a salient remedy to sustain ecological network stability, thereby leading to heightened ecological efficacy. Nevertheless, extant research pertaining to ecological network resilience predominantly centers around static assessment, disregarding the external dynamic disturbances as well as changes in resilience over long time-series. Furthermore, scant attention has been given to the simultaneous incorporation of both structural and functional attributes in the selection of indicators for resilience assessment. In this study, taking Nanjing as an example, with a five-year interval, we determined the spatial scope of the ecological networks in 2000–2020, used two disturbance scenario simulation methods, probabilistic attack and deterministic attack, and finally optimized the ecological network with the goal of resilience enhancement. The results show that (1) the resilience index thresholds of the ecological networks decreased from 0.43 to 0.37, and the network resilience became progressively worse, but the decline in resilience index thresholds decreased in recent years. (2) The phenomenon of resurgent functional resilience increased, and ecological network redundancy increased. (3) In recent years, critical resilience nodes evinced a trend characterized by a diminishment of significance in the central region and a concomitant enhancement of importance in the southern domain. (4) The functional and structural optimization strategies increased the resilience index thresholds by 0.06 and 0.11, respectively. This study advances the refinement of methodologies and frameworks germane to the dynamic assessment of ecological network resilience, thereby furnishing instructive guidance for the fortification of urban ecosystem resilience and the promotion of sustainable urban governance.