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Université de Fribourg

A guideline to study the feasibility domain of multi-trophic and changing ecological communities

Song, Chuliang ; Rohr, Rudolf P. ; Saavedra, Serguei

In: Journal of Theoretical Biology, 2018, vol. 450, p. 30–36

The feasibility domain of an ecological community can be described by the set of environmental abiotic and biotic conditions under which all co-occurring and interacting species in a given site and time can have positive abundances. Mathematically, the feasibility domain corresponds to the parameter space compatible with positive (feasible) solutions at equilibrium for all the state variables...

Université de Fribourg

Comparing species interaction networks along environmental gradients: Networks along environmental gradients

Pellissier, Loïc ; Albouy, Camille ; Bascompte, Jordi ; Farwig, Nina ; Graham, Catherine ; Loreau, Michel ; Maglianesi, Maria Alejandra ; Melián, Carlos J. ; Pitteloud, Camille ; Roslin, Tomas ; Rohr, Rudolf ; Saavedra, Serguei ; Thuiller, Wilfried ; Woodward, Guy ; Zimmermann, Niklaus E. ; Gravel, Dominique

In: Biological Reviews, 2018, vol. 93, no. 2, p. 785–800

Knowledge of species composition and their interactions, in the form of interaction networks, is required to understand processes shaping their distribution over time and space. As such, comparing ecological networks along environmental gradients represents a promising new research avenue to understand the organization of life. Variation in the position and intensity of links within networks...

Université de Fribourg

Towards the integration of niche and network theories

Godoy, Oscar ; Bartomeus, Ignasi ; Rohr, Rudolf P. ; Saavedra, Serguei

In: Trends in Ecology & Evolution, 2018, vol. 33, no. 4, p. 287–300

The quest for understanding how species interactions modulate diversity has progressed by theoretical and empirical advances following niche and network theories. Yet, niche studies have been limited to describe coexistence within tropic levels despite incorporating information about multi-trophic interactions. Network approaches could address this limitation, but they have ignored the...

Université de Fribourg

Why are some plant–pollinator networks more nested than others?

Song, Chuliang ; Rohr, Rudolf P. ; Saavedra, Serguei

In: Journal of Animal Ecology, 2017, vol. 86, no. 6, p. 1417–1424

Empirical studies have found that the mutualistic interactions forming the structure of plant–pollinator networks are typically more nested than expected by chance alone. Additionally, theoretical studies have shown a positive association between the nested structure of mutualistic networks and community persistence. Yet, it has been shown that some plant–pollinator networks may be more...

Université de Fribourg

Reorganization of interaction networks modulates the persistence of species in late successional stages

Saavedra, Serguei ; Cenci, Simone ; del-Val, Ek ; Boege, Karina ; Rohr, Rudolf P.

In: Journal of Animal Ecology, 2017, vol. 86, no. 5, p. 1136–1146

Ecological interaction networks constantly reorganize as interspecific interactions change across successional stages and environmental gradients. This reorganization can also be associated with the extent to which species change their preference for types of niches available in their local sites. Despite the pervasiveness of these interaction changes, previous studies have revealed that...

Université de Fribourg

A structural approach for understanding multispecies coexistence

Saavedra, Serguei ; Rohr, Rudolf P. ; Bascompte, Jordi ; Godoy, Oscar ; Kraft, Nathan J. B. ; Levine, Jonathan M.

In: Ecological Monographs, 2017, p. -

Although observations of species-rich communities have long served as a primary motivation for research on the coexistence of competitors, the majority of our empirical and theoretical understanding comes from two-species systems. How much of the coexistence observed in species rich communities results from indirect effects among competitors that only emerge in diverse systems remains poorly...

Université de Fribourg

Persist or produce: a community trade-off tuned by species evenness

Rohr, Rudolf P. ; Saavedra, Serguei ; Peralta, Guadalupe ; Frost, Carol M. ; Bersier, Louis-Félix ; Bascompte, Jordi ; Tylianakis, Jason M.

In: The American Naturalist, 2016, vol. 188, no. 4, p. 411–422

Understanding the effects of biodiversity on community persistence and productivity is key to managing both natural and production systems. Because rare species face greater danger of extinction, species evenness, a measure of how similar abundances are across species in a community, is seen as a key component of biodiversity. However, previous studies have failed to find a consistent...

Université de Fribourg

How structurally stable are global socioeconomic systems?

Saavedra, Serguei ; Rohr, Rudolf P ; Gilarranz, Luis J ; Bascompte, Jordi

In: Journal of The Royal Society Interface, 2014, vol. 11, no. 100, p. 20140693

The stability analysis of socioeconomic systems has been centred on answering whether small perturbations when a system is in a given quantitative state will push the system permanently to a different quantitative state. However, typically the quantitative state of socioeconomic systems is subject to constant change. Therefore, a key stability question that has been under-investigated is how...

Université de Fribourg

Stock fluctuations are correlated and amplified across networks of interlocking directorates

Saavedra, Serguei ; Gilarranz, Luis J ; Rohr, Rudolf P. ; Schnabel, Michael ; Uzzi, Brian ; Bascompte, Jordi

In: EPJ Data Science, 2014, vol. 3, no. 1, p. 30

Traded corporations are required by law to have a majority of outside directors on their board. This requirement allows the existence of directors who sit on the board of two or more corporations at the same time, generating what is commonly known as interlocking directorates. While research has shown that networks of interlocking directorates facilitate the transmission of information between...

Université de Fribourg

Nested species interactions promote feasibility over stability during the assembly of a pollinator community

Saavedra, Serguei ; Rohr, Rudolf P. ; Olesen, Jens M. ; Bascompte, Jordi

In: Ecology and Evolution, 2016, p. -

The foundational concepts behind the persistence of ecological communities have been based on two ecological properties: dynamical stability and feasibility. The former is typically regarded as the capacity of a community to return to an original equilibrium state after a perturbation in species abundances and is usually linked to the strength of interspecific interactions. The latter is the...