Managing oxidative stress is an important physiological function for all aerobic organisms, particularly during periods of prolonged high metabolic activity, such as long-distance migration across ecological barriers. However, no previous study has investigated the oxidative status of birds at different stages of migration and whether that oxidative status depends on the condition of the birds. In this study, we compared (1) energy stores and circulating oxidative status measures in (a) two species of Neotropical migrants with differing migration strategies that were sampled at an autumn stopover site before an ecological barrier; and (b) a species of trans-Saharan migrant sampled at a spring stopover site after crossing an ecological barrier; and (2) circulating oxidative measures and indicators of fat metabolism in a trans-Saharan migrant after stopovers of varying duration (0–8 nights), based on recapture records. We found fat stores to be positively correlated with circulating antioxidant capacity in Blackpoll Warblers and Red-eyed Vireos preparing for fall migration on Block Island, USA, but uncorrelated in Garden Warblers on the island of Ponza, Italy, after a spring crossing of the Sahara Desert and Mediterranean Sea. In all circumstances, fat stores were positively correlated with circulating lipid oxidation levels. Among Garden Warblers on the island of Ponza, fat anabolism increased with stopover duration while oxidative damage levels decreased. Our study provides evidence that birds build antioxidant capacity as they build fat stores at stopover sites before long flights, but does not support the idea that antioxidant stores remain elevated in birds with high fuel levels after an ecological barrier. Our results further suggest that lipid oxidation may be an inescapable hazard of using fats as the primary fuel for flight. Yet, we also show that birds on stopover are capable of recovering from the oxidative damage they have accrued during migration, as lipid oxidation levels decrease with time on stopover. Thus, the physiological strategy of migrating songbirds may be to build prophylactic antioxidant capacity in concert with fuel stores at stopover sites before a long-distance flight, and then repair oxidative damage while refueling at stopover sites after long-distance flight.

ABSTRACT. All air-breathing organisms must face the challenge of oxidative damage, and understanding how animals cope can lend insight into their ecology. Unlike other vertebrates, birds rely primarily on fats to fuel endurance exercise such as migration, and therefore face a greater potential for damage from the reactive by-products of their own metabolism. We review the physiological ecology of migrating birds through the lens of oxidation-reduction chemistry, underscoring how oxidative balance in wild birds may affect their dietary choices and use of critical stopover habitats during migration. Recent studies reveal that migratory birds prepare for oxidative challenges either by up-regulating endogenous antioxidants or by consuming them in their diet, and they repair oxidative damage after long flights, although much remains to be discovered about how birds maintain oxidative balance over the course of migration. We conclude by describing some of the most used and useful measures of antioxidant status and oxidative damage that field ornithologists can include in their tool kit of techniques to probe the oxidative balance of wild birds. RESUMEN. Balance oxidativo en aves: introducción para ornitólogos desde losátomos hocia los organismos y a la ecologíaTodos los organismos que respiran aire deben enfrentarse al reto del daño por oxidación. Entender como los animales pueden manejar este daño puede dar indicios sobre su ecología. Contrario a otros vertebrados, las aves se basan primordialmente en grasas como combustible para ejercicios que requieren una resistencia alta, como la migración. Por lo tanto, las aves se enfrentan a un mayor potencial daño oxidativo por parte de los subproductos reactivos de su propio metabolismo. Aquí revisamos la ecología fisiológica de aves migratorias a través de la lupa de la química de oxido-reducción, resaltando como el balance oxidativo en aves silvestres puede afectar sus preferencias en la dieta y uso de hábitats críticos de escala durante la migración. Estudios recientes revelan que las aves migratorias se preparan para los retos oxidativos mediante el incremento de antioxidantes endógenos, o mediante el consumo en su dieta y reparan daños oxidativos después de vuelos largos. Sin embargo, aun queda mucho por descubrir sobre como las aves mantienen su balance oxidativo a lo largo del transcurso de la migración. Concluimos describiendo algunos de las medidasútiles y mas utilizadas del estatus antioxidante y daño oxidativo que los ornitólogos de campo puede incluir dentro de sus técnicas para la exploración del balance oxidativo en aves silvestres.Key words: antioxidants, lipid oxidation, measurement, migration, stopover Compared to other vertebrates, birds are unique endurance athletes capable of sustaining high metabolic rates while relying on fat as their primary fuel. All vertebrates generate reactive byproducts during oxygen-based metabolism, and exercise requires an increase in energy production and consequently can increase oxidative byproducts. Endurance flights of migr...

Ecological forecasting has vast potential to support environmental decision making with repeated, testable predictions across management-relevant timescales and locations. Yet resource managers rarely use co-designed forecasting systems or embed them in decision making. Although prediction of planned management outcomes is particularly important for biological invasions to optimize when and where resources should be allocated, spatial-temporal models of spread typically have not been openly shared, iteratively updated, or interactive to facilitate exploration of management actions. We describe a species-agnostic, open-source framework -called the Pest or Pathogen Spread (PoPS) Forecasting Platform -for co-designing near-term iterative forecasts of biological invasions. Two case studies are presented to demonstrate that iterative calibration yields higher forecast skill than using only the earliest-available data to predict future spread. The PoPS framework is a primary example of an ecological forecasting system that has been both scientifically improved and optimized for real-world decision making through sustained participation and use by management stakeholders.

Participatory research methods are increasingly used to collectively understand complex social-environmental problems and to design solutions through diverse and inclusive stakeholder engagement. But participatory research rarely engages stakeholders to co-develop and co-interpret models that conceptualize and quantify system dynamics for comparing scenarios of alternate action. Even fewer participatory projects have engaged people using geospatial simulations of dynamic landscape processes and spatially explicit planning scenarios. We contend that geospatial participatory modeling (GPM) can confer multiple benefits over non-spatial approaches for participatory research processes, by (a) personalizing connections to problems and their solutions through visualizations of place, (b) resolving abstract notions of landscape connectivity, and (c) clarifying the spatial scales of drivers, data, and decision-making authority. We illustrate through a case study how GPM is bringing stakeholders together to balance population growth and conservation in a coastal region facing dramatic landscape change due to urbanization and sea level rise. We find that an adaptive, iterative process of model development, sharing, and revision drive innovation of methods and ultimately improve the realism of land change models. This co-production of knowledge enables all participants to fully understand problems, evaluate the acceptability of trade-offs, and build buy-in for management actions in the places where they live and work.

Models that are both spatially and temporally dynamic are needed to forecast where and when non-native pests and pathogens are likely to spread, to provide advance information for natural resource managers. The potential US range of the invasive spotted lanternfly (SLF, Lycorma delicatula) has been modeled, but until now, when it could reach the West Coast’s multi-billion-dollar fruit industry has been unknown. We used process-based modeling to forecast the spread of SLF assuming no treatments to control populations occur. We found that SLF has a low probability of first reaching the grape-producing counties of California by 2027 and a high probability by 2033. Our study demonstrates the importance of spatio-temporal modeling for predicting the spread of invasive species to serve as an early alert for growers and other decision makers to prepare for impending risks of SLF invasion. It also provides a baseline for comparing future control options.