Access to global wheat reserves determines country-level vulnerability to conflict-induced Ukrainian wheat supply disruption.

The Russia-Ukraine conflict reduced global wheat supplies, yet the food security implications vary across countries. We identify a 39% decrease in Ukrainian wheat exports in 2022 resulting in >70% import losses in some of the countries most vulnerable to these disruptions, with substantial impacts felt in Egypt, Oman, Saudi Arabia, Libya, Mauritania, Yemen and Lebanon. Differential impacts are a function of access to capital and international trade, suggesting the need for policy measures to defuse the impending food crisis.

Food demand displaced by global refugee migration influences water use in already water stressed countries.

Millions of people displaced by conflicts have found refuge in water-scarce countries, where their perceived effect on water availability has shaped local water security discourses. Using an annual global data set, we explain the effects of refugee migrations on the host countries' water stress through the food demand displaced by refugees and the water necessary to produce that food. The water footprint of refugee displacement increased by nearly 75% globally between 2005 and 2016.

Eco-hydrological modelling of channel network dynamics-part 2: application to metapopulation dynamics.

Temporal variations in the configuration of the flowing portion of stream networks are observed in the large majority of rivers worldwide. However, the ecological implications of river network expansions/retractions remain poorly understood, owing to the lack of computationally efficient modelling tools conceived for the long-term simulation of river network dynamics. Here, we couple a stochastic approach for the simulation of channel network expansion and retraction (described in a companion paper) with a dynamic version of a stochastic occupancy metapopulation model.

Eco-hydrological modelling of channel network dynamics-part 1: stochastic simulation of active stream expansion and retraction.

Dynamic changes in the active portion of stream networks represent a phenomenon common to diverse climates and geologic settings. However, mechanistically describing these processes at the relevant spatiotemporal scales without huge computational burdens remains challenging. Here, we present a novel stochastic framework for the effective simulation of channel network dynamics capitalizing on the concept of 'hierarchical structuring of temporary streams'-a general principle to identify the activation/deactivation order of network nodes.

Emergent dispersal networks in dynamic wetlandscapes.

The connectivity among distributed wetlands is critical for aquatic habitat integrity and to maintain metapopulation biodiversity. Here, we investigated the spatiotemporal fluctuations of wetlandscape connectivity driven by stochastic hydroclimatic forcing, conceptualizing wetlands as dynamic habitat nodes in dispersal networks. We hypothesized that spatiotemporal hydrologic variability influences the heterogeneity in wetland attributes (e.

Stochastic dynamics of wetlandscapes: Ecohydrological implications of shifts in hydro-climatic forcing and landscape configuration.

Wetlands are embedded in landscapes in fractal spatial patterns, and are characterized by highly dynamic, interlinked hydrological, biogeochemical, and ecological functions. We propose here a stochastic approach to evaluate and predict the spatiotemporal hydrologic variability of wetlands at landscape scale (100 km). Stochastic hydro-climatic forcing (daily rainfall and evapotranspiration) and the landscape topographic setting (spatial structure of wetlands within the landscape) are key drivers of wetland eco-hydrologic functionality.