Ecological responses to climate change may depend on complex patterns of variability in weather and local microclimate that overlay global increases in mean temperature. Here, we show that high-resolution temporal and spatial variability in temperature drives the dynamics of range expansion for an exemplar species, the butterfly Hesperia comma. Using fine-resolution (5 m) models of vegetation s...

Complex interactions among climate change and ecosystem processes (plant demographics, tree-grass interactions, grazers, browsers, fire and nitrogen) challenge our ability to predict future carbon stocks in Africa and other tropical regions. Recent work suggests Africa has a near zero decade-scale carbon balance, but that climate fluctuations induce sizeable variability in ecosystem productivit...

Concerns over the effects of private land use on the supply of environmental amenities have led to an increasing global reliance on conservation contracting initiatives (Ferraro and Kiss 2002). The term “conservation contracting” describes the contractual transfer of payments from one party (e.g., government) to another (e.g., landowner) in exchange for land use practices that contribute to the...

Dynamic vegetation models forced with spatially homogeneous biophysical parameters are capable of producing average productivity and biomass values for the Amazon basin forest biome that are close to the observed estimates, but these models are unable to reproduce observed spatial variability. Recent observational studies have shown substantial regional spatial variability of above-ground produ...

This paper explores the computational modeling of nonlocal strain, damage, and fracture in concrete, considering isolated contribution two random, spatially variable properties related to process: Young’s modulus (E) tensile strength (f t ). Applying a continuum damage model, heterogeneous specimens concrete with random varying E or f were found produce substantial differences when contrasted t...

The long-term goals of this project are to identify and quantify specific optical and chemical characteristics of the colored particulate and dissolved fractions of the Penobscot River water system that are associated with defined land use activities (land use proxies), and to determine the scales of variability over which these proxies can be detected both temporally (i.e. seasonal and episodi...

We study the influence of spatially varying reaction rates on a spatial stochastic two-species Lotka-Volterra lattice model for predator-prey interactions using two-dimensional Monte Carlo simulations. The effects of this quenched randomness on population densities, transient oscillations, spatial correlations, and invasion fronts are investigated. We find that spatial variability in the predat...

Randomly connected networks of excitatory and inhibitory spiking neurons provide a parsimonious model of neural variability, but are notoriously unreliable for performing computations. We show that this difficulty is overcome by incorporating the well-documented dependence of connection probability on distance. Spatially extended spiking networks exhibit symmetry-breaking bifurcations and gener...

We formulate equations for the slow time dynamics of fluid motion that self consistently account for the effects of the variability upon the mean. The time-average effects of the fluctuations introduce nonlinear dispersion that acts to spatially smooth the transport velocity of the mean flow relative to its circulation or momentum velocity, by the inversion of a Helmholtz operator whose length ...