Ferenc Jordán

Università di Parma | UNIPR

News outlets publicize scientific research findings that have not been peer reviewed yet, and they often do it with active contribution by the authors of the unpublished manuscripts. While researchers are aware of the importance of the peer review process and what it means to discuss findings before manuscripts are accepted for publication, the gen...

The advent of metabarcoding (metaB) in aquatic ecology has provided a huge amount of information on plankton biodiversity worldwide. However, the large datasets obtained with that approach are still partially explored, especially for what concerns the study of trophic interactions and food webs. In this study, we analysed a metaB time series from t...

Managing sustainable marine fisheries is one of the greatest challenges for humanity. The complexity of the issue calls for the development of socio-ecological models and the integration of our knowledge from several disciplines. Here we focus on the ecological aspects of sustainability: how can we increase the catch and, at the same time, possibly...

Life is organized into more or less well-defined organizational levels, connected both horizontally and vertically. Our knowledge is richer along the horizontal levels (e.g. inter-specific interactions in multispecies communities), while vertical thinking (e.g. individual-level variability of the prey in a predator-prey interaction) is more challen...

Loss of biodiversity comprehends not only the extinction of individual species, but also the loss of the ecological interactions among them. Survival of species, continuation of ecosystem functioning in nature, and ecosystem services to humans depend on the maintenance of well-functioning networks of species interactions (e.g. plant–pollinator netw...

Network analysis is employed in biodiversity studies to explore the possible ecological implications of taxa co-occurrences across time or space, but the conceptual robustness of this approach is still under debate. Herein, by focusing our attention on a marine pelagic community previously described by metabarcoding data gathered over a time-series...

In ecological systems, multiple interactions connect various kinds of components. Strong and weak as well as positive and negative effects cause complex dynamics and often quite unpredictable processes. Human impact is added to this complexity, with all of its diverse effects. In this paper, we present a case study on the Kelian river ecosystem (Bo...

Biodiversity is measured from various perspectives. One of them, functional diversity, quantifies the heterogeneity in species traits and roles in an ecosystem. One important aspect of species roles is their interactions with other species, i.e. their network role. We therefore investigate here functional diversity from the network perspective. Spe...

Quantitative methods of prioritization are necessary to optimize the selection of protected areas for biodiversity conservation. Reserve selection is traditionally based on single species, considers representative habitats or, occasionally, spatial configuration but mostly the needs of the society. However, protecting particular species as independ...

Loss of biodiversity comprehends not only the extinction of individual species, but also the loss of the ecological interactions among them. Survival of species, continuation of ecosystem functioning in nature, and ecosystem services to humans depend on the maintenance of well-functioning networks of species interactions (e.g. plant-pollinator netw...

Food webs are often simulated dynamically to explore how trophic interactions influence resource and consumer abundances. As large trophic networks cannot be simulated in their original size – it would be too computationally expansive – they are shrunk by aggregating species together. However, key species may get lumped during this process, masking...

Networks of trophic interactions provide a lot of information on the functioning of marine ecosystems. Beyond feeding habits, three additional traits (mobility, size, and habitat) of various organisms can complement this trophic view. The combination of traits and food web positions are studied here on a large food web database. The aim is a better...

Increasingly we are discovering that the interactions between individuals within social groups can be quite complex and flexible. Social network analysis offers a toolkit to describe and quantify social structure, the patterns we observe, and evaluate the social and environmental factors that shape group dynamics. Here, we used 14 Gunnison’s prairi...

Network analysis offers a rich toolkit to study various graph models in biology. In ecology, centrality indices have been suggested to indicate keystone species in interaction networks and to quantify their importance in an ecosystem. There is a large number of centrality indices, however, and it is often unclear what is their precise biological me...

In the era of bioinformatics and big data, ecological research depends on large and easily accessible databases that make it possible to construct complex system models. Open-access data repositories for food webs via publications and ecological databases (e.g. EcoBase) are becoming increasingly common, yet certain ecosystem types are underrepresen...

Food web research needs to be predictive in order to support decisions system-based conservation. In order to increase predictability and applicability, complexity needs to be reduced to simple and clear results. One question emerging frequently is whether certain perturbations (environmental effects or human impact) have positive or negative effec...

The role of organisms in community assembly and functioning is a crucial question of community ecology. We address this issue in a particular marine coastal ecosystem at SE Pacific: although kelp forests and urchin barrens are conspicuous benthic systems in rocky habitats, only a few studies have been focused on studying their successional patterns...

Contrasting reductionistic versus holistic views, it is a general question whether adding the parts equals the sum. In the time of multiple drivers of anthropogenic change, it is a crucial issue, and better understanding additivity is critical for strategy and management. More particular research questions ask what are the community effects of the...

Benthic ecosystems along the north-central Chilean coast are characterised by the presence of kelp forests, considered as ecosystem engineer or niche constructor organisms. Despite their essential ecological role, in the last years kelp forests have been heavily exploited and disturbed by artisanal fishing, inducing drastic changes in such benthic...

Coastal ecosystems, being on the interface between various habitats and also heavily influenced by human impact, face most challenges influencing natural and social systems. This book presents a collection of frontline research on Latin-American coastal marine ecosystem models, written mostly by Latin-American authors. Linking parts to the whole, e...

The book presents a collection of large-scale network-modeling studies on coastal systems in Latin America. It includes a novel description of the functioning of coastal complex ecosystems and also predicts how natural and human-made disturbances percolate through the networks. Coastal areas belong to the most populated ecosystems around the globe,...

Abstract The position of a node in a social network, or node centrality, can be quantified in several ways. Traditionally, it can be defined by considering the local connectivity of a node (degree) and some non-local characteristics (distance). Here, we present an approach that can quantify the interaction structure of signed digraphs and we define...

The geographic isolation of the Antarctic continent offers an interesting opportunity to quantify and qualify the actual ecological conditions and the most sensitive components from an ecosystem perspective. Antarctic coastal ecosystems are under severe stress as a consequence of climate change, which could facilitate biological invasions, reduced...

Aquatic ecosystems face several major challenges from the introduction and invasion of species, to overfishing. In order to better manage these situations, we need predictive models, where diverse scenarios can be simulated and tested. One key challenge to address is how to quantify the relationships between single-species disturbances and their mu...

Species are characterized by physiological and behavioral plasticity, which is part of their response to environmental shifts. Nonetheless, the collective response of ecological communities to environmental shifts cannot be predicted from the simple sum of individual species responses, since co‐existing species are deeply entangled in interaction n...

Network models are among the most powerful tools in systems ecology. As trophic relationships (i.e. who eats whom) are among the most frequent interspecific interactions, food webs serve well as system models. To better understand ecosystem dynamics, neither strictly local (focusing on individual species) nor strictly global (focusing on the whole...

We briefly discuss the relationship between the biological knowledge and the methodological issues related to trait-based ecological analyses. We provide illustrative examples and argue that the biological novelty of trait-based research is generally less than expected - while new information is mostly coming from data management and methodology.

Species are embedded in a web of intricate trophic interactions. Understanding the functional role of species in food webs is of fundamental interests. This is related to food web position, so positional similarity may provide information about functional overlap. Defining and quantifying similar trophic functioning can be addressed in different wa...

Important species may be in critically central network positions in ecological interaction networks. Beyond quantifying which one is the most central species in a food web, a multinode approach can identify the key sets of the most central n species as well. However, for sets of different size n , these structural keystone species complexes may dif...

Individual nature reserves are rarely able to host viable populations. A potential solution is designing reserve systems where local reserves are connected to each other, allowing for dispersal. We use network analysis to identify habitat areas that are key for system connectivity, and should therefore be selected for protection.

In community ecology, network perspective can be useful in answering many different questions: besides describing and comparing different systems, it is often used to quantify the relative importance of functional groups and to identify keystone species within ecosystems. Despite the fact that food webs seem to be strictly hierarchical, food web m...

Food webs dynamically react to perturbations and it is an open question how additive are the effects of single-species perturbations. Network structure may have topological constraints on additivity and this influences community response. Better understanding the relationships between single-species and multi-species perturbations can be useful for...

Using network analysis for making predictions about food web dynamics is one of the major challenges in systems ecology. Since there are several notoriously difficult methodological problems with food webs, only a comparative perspective can help. We study a standard database for trophic flow networks and analyse the correlation between structure a...

Landscape connectivity is of major importance in biodiversity conservation, and is one of the key aspects to be taken into consideration in the spatial design of networks of protected areas. Graph-theoretical approaches are useful in modelling habitat connectivity and defining priority areas for the protection of connectivity. This prioritization c...

A keystone species complex (KSC) is a small set of interacting species that play an outstandingly important role in community organization. Two KSC indices are suggested and have been calculated in the coastal benthic/pelagic ecosystem of Fildes Bay, King George Island (Antarctica). These indices of keystoneness emerge after considering: (1) functi...

HIGHLIGHTS: ● Maximum sustainable yield (MSY) should be assessed in multi-species context ● Single-species and pairwise disturbances on food web simulations ● We determine which pairs of species show non-additive community effects when disturbed ● We study the topological relationship of these species pairs ● Perturbing pairs of species that are ei...

Urban green spaces are very important for human wellbeing and environmental sustainability. The efficiency of managing urban green spaces often depends on communication and integration of information. We performed a social network analysis survey for assessing the communication structure among the staff in four New Delhi city parks. We were interes...

Habitat connectivity is a major concern in biodiversity conservation. Network analysis provides efficient tools for assessing landscape connectivity and identifying priority areas for protection. Widespread approaches consist of ranking individual habitat patches by their importance for connectivity. However, depending on the spatial arrangement of...

Introduction The dynamical behavior of individuals in ecosystems involves a multifaceted set of interaction types and processes that take place at different hierarchical levels. We present an individual-based, stochastic model that considers species dynamics at three hierarchical levels: population, community, and metacommunity. We use an individua...

Introduction Trophic interactions are one of the most important aspects shaping ecological communities, and the food-web paradigm has played a major role in the development of ecology as a science. Early food-web models attempted to simulate the flow of energy and biomass within local communities (Odum, 1956) or describe the structure of feeding re...

Individual-Based Modeling in Conservation Biology A major challenge for food-web research is studying diversity and variability more explicitly. This means a focus on individual-level variability in populations (Bolnick et al., 2011) that hopefully might help to better understand how structural properties predict dynamical behavior (Dunne, 2006). O...

We studied 25 published marine food web models. We compared the sizes of carbon flows to the strength of interactions inferred by a topological measure. We determined which network properties correlate with a significant relationship between major flows and strong interactions. It is concluded that small and dense networks show significant interact...

One of the most important aims of conservation ecology is to quantify the relative importance of species and find keystone species within ecosystems. A possible approach for this problem is the network perspective which focuses on the structure and interactions of community webs and is able to define the positional importance of species with the he...

Coexisting bacteria form various microbial communities in human body parts. In these ecosystems they interact in various ways and the properties of the interaction network can be related to the stability and functional diversity of the local bacterial community. In this study, we analyze the interaction network among bacterial OTUs in 11 locations...

There is a growing interest in understanding the structure–dynamic relationship of ecological networks. Ecological network changes along primary successions are poorly known: to address such topic, gradient of primary succession on glacier forelands is an ideal model, as sites of different age since deglaciation stand for different ecosystem develo...

Background The human intestinal microbiota changes from being sparsely populated and variable to possessing a mature, adult-like stable microbiome during the first 2 years of life. This assembly process of the microbiota can lead to either negative or positive effects on health, depending on the colonization sequence and diet. An integrative study...

Ecological and eco-social network models were constructed with different levels of complexity in order to represent and evaluate management strategies for controlling the alien species Pterois volitans in Chinchorro bank (Mexican Caribbean). Levins´s loop analysis was used as a methodological framework for assessing the local stability (considered...

Living in larger, more complex social groups is assumed to increase disease risk in primates, yet empirical evidence is mixed on how group size or structure influence disease dynamics. We studied the networks of 42 primate social groups of varying size to test whether larger social groups displayed quantitatively different network structures than s...

Increased risk of infectious disease is assumed to be a major cost of group living, yet empirical evidence for this effect is mixed. We studied whether larger social groups are more subdivided structurally. If so, the social subdivisions that form in larger groups may act as barriers to the spread of infection, weakening the association between gro...

Rarity of species is often considered to set priorities for biodiversity conservation. Less abundant species are expected to be at higher risk of extinction and make significant contribution to food web functioning. However, the relationship between species abundance and position in food webs is still unclear. Here we tested possible correlations b...

In complex ecosystem models, relationships between species include a large number of direct interactions and indirect effects. In order to unveil some simple and better understandable relationships, it is useful to study the asymmetry of inter-specific effects. We present a simple approach for this based on stochastic food web simulations from prev...

Climate change was observed during the past century and glacier retreat documented this warming period. Glacier forelands are ideal models to study community dynamics along a chronosequence. Nevertheless, knowledge about how plants and flower-visiting insects interact along a primary succession is still scarce. To fill the gap we performed network...

We propose the use of a new methodological scheme for exploring and quantifying structure in bipartite ecological networks. In this, graphical visualization and numerical measurement are combined, offering a unique possibility for network analysis on a coherent conceptual basis. Dissimilarity between all species pairs in either group of constitutin...

In recent years the experimental and computational research approaches in life sciences have been abandoning the reductionist vision to adopt a system-level point of view. Unlike the reductionist approach, the framework of systems theory proposes an integrative planning out to model complex biological phenomena. The integrative modelling is the mai...

One source of complexity in ecological systems is the hierarchical organization of parallel biological processes. Our 'horizontal' knowledge describing different levels is quite massive, but the understand-ing of their vertical interactions is very poor. We present a toy model linking social networks, food webs and a landscape graph. Horizontal pro...

Although the conflict between conservation efforts and economic growth is a major topic of conservation science, the conflicts between different conservation projects are much less documented and represented in the literature. We provide an overview of some case studies where these conflicts arise and discuss how to manage and solve them. We argue...

There is a growing recognition of the need to integrate non‐trophic interactions into ecological networks for a better understanding of whole‐community organization. To achieve this, the first step is to build networks of individual non‐trophic interactions. In this study, we analyzed a network of interdependencies among bird species that participa...

One of the main concerns of shrimp fisheries is the associ-ated impact on ecosystem biodiversity, particularly on fish assemblages that are poorly characterized yet likely very rele-vant to the health of the ecosystem. The continental shelf along the eastern coast of the mouth of the Gulf of Califor-nia is a region of high biodiversity that harbors...

Understanding queen succession could be a key contribution to the better understanding of the origins and evolution of eusociality. In order to investigate the nature of organizational changes during queen succession, we analyzed two closely related paper wasp species (Ropalidia cyathiformis and Ropalidia marginata). We compared the effects of in v...

Stochastic kinetic methods are currently considered to be the most realistic and elegant means of representing and simulating the dynamics of biochemical and biological networks. Deterministic versus stochastic modelling in biochemistry and systems biology introduces and critically reviews the deterministic and stochastic foundations of biochemical...

Many species inhabiting the benthic marine ecosystems of the central and northern Chilean coast have been intensively harvested and this exploitation has increased considerably in recent years. Despite this harvest pressure, few studies have attempted to establish a more holistic, systems-based management plan. On the contrary, research continues t...

Several important ecological problems are related to the hierarchical organization of ecosystems. In order to better understand the ecology of a population, its internal social structure and its interspecific interactions can be equally important, but it may also matter how it is embedded in a larger-scale metacommunity system. While we know a lot...

The causal relationship between species diversity and environmental (landscape) heterogeneity has been a long-lasting interest among ecologists. In fact, environmental heterogeneity is considered to be one of the main factors associated with biodiversity given that areas with higher environmental heterogeneity can host more species due to their hig...

Network models are traditional in community ecology. For example, they provide a rich analytical toolkit to put higher predators into a multispecies context. Better understanding their top-down effects and the potential bottom-up control on them would be of key importance for predictive ecosystem management. Food web architecture may be used to pre...

Robustness analysis for the betweenness centrality ranking for polarity, cytokinesis and cell cycle networks in fission yeast. We analysed the robustness of ranking proteins by BC centrality in the presence of imperfect network interaction data. We added 10% extra edges at random to the network, calculated BC for every node after adding the edges,...

Functional modularity in the core networks. To calculate how much the functional modularity (the ratio of interactions between nodes with a shared GO category versus interactions between nodes with no GO category in common) observed for the core network of budding and fission yeast deviated from a random network, we kept all the category labels for...