Networks

The predictability of qualitative food web dynamics in response to extinction and invasion

Food webs are extraordinarily complex, containing myriad direct interactions and indirect effects. Determining how this network of interactions and effects influences a food web’s qualitative dynamics is a challenging task, especially because data …

Exact probabilities for the indeterminacy of complex networks as perceived through press perturbations

We consider the goal of predicting how complex networks respond to chronic (press) perturbations when characterizations of their network topology and interaction strengths are associated with uncertainty. Our primary result is the derivation of exact …

Characterizing species interactions to understand press perturbations: What is the community matrix?

The community matrix is among ecology's most important mathematical abstractions, formally encapsulating the interconnected network of effects that species have on one another's populations. Despite its importance, the term “community matrix” has …

Complexity increases predictability in allometrically constrained food webs

All ecosystems are subjected to chronic disturbances, such as harvest, pollution, and climate change. The capacity to forecast how species respond to such press perturbations is limited by our imprecise knowledge of pairwise species interaction …

An Online Database for Informing Ecological Network Models: http://kelpforest.ucsc.edu

Ecological network models and analyses are recognized as valuable tools for understanding the dynamics and resiliency of ecosystems, and for informing ecosystem-based approaches to management. However, few databases exist that can provide the life …

Complex networks in kelp forest ecosystems - Visualizing big data

Kelp forests serve as an integral abode for aquatic species. Kelp forests are one of the most productive terrestrial systems, providing its denizens the conditions necessary for growth. Wave action allows for the constant motion of the seaweed, …

Probabilistic patterns of interaction: the effects of link-strength variability on food web structure

Patterns of species interactions affect the dynamics of food webs. An important component of species interactions that is rarely considered with respect to food webs is the strengths of interactions, which may affect both structure and dynamics. In …

Structure and mechanism of diet specialisation: testing models of individual variation in resource use with sea otters

Studies of consumer‐resource interactions suggest that individual diet specialisation is empirically widespread and theoretically important to the organisation and dynamics of populations and communities. We used weighted networks to analyze the …

Predicting community responses to perturbations in the face of imperfect knowledge and network complexity

How best to predict the effects of perturbations to ecological communities has been a long‐standing goal for both applied and basic ecology. This quest has recently been revived by new empirical data, new analysis methods, and increased computing …

Trophic omnivory and the structure, strength, and nonlinear nature of species interactions across a productivity gradient

Two elements of food webs add significantly to their complexity: The presence of trophic omnivores and the nonlinear nature of predator-prey interactions. I introduce a new observational method for estimating the strengths of species interactions …