A major restriction in predicting plant community response to future climate change is a lack of long‐term data needed to properly assess species and community response to climate and identify a baseline to detect climate anomalies. Here, we use a 106‐year dataset on a Sonoran Desert plant community to test the role of extreme temperature and precipitation anomalies on community dynamics at the decadal scale and over time. Add...

Offspring polymorphism is a reproductive strategy where individual organisms simultaneously produce offspring that differ in morphology and ecology. It occurs across the Tree of Life but is particularly common among plants, where it is termed seed (diaspore) heteromorphism. The prevalence of this strategy in unpredictably varying environments has resulted in the assumption that it serves as a bet‐hedging mechanism. We found 10...

Plant germination ecology involves continuous interactions between changing environmental conditions and the sensitivity of seed populations to respond to those conditions at a given time. Ecologically meaningful parameters characterizing germination capacity (or dormancy) are needed to advance our understanding of the evolution of germination strategies within plant communities. The germination traits commonly examined (e.g.,...

Phylogenetically informed trait comparisons across entire communities show promise in advancing community ecology. We use this approach to better understand the composition of a community of winter annual plants with multiple decades of monitoring and detailed morphological, phenological and physiological measurements. Previous research on this system revealed a physiological trade‐off among dominant species that accurately pr...

Numerous mechanisms may allow species to coexist. We tested for frequency‐dependent predation, a mechanism predicted by theory and established as a foraging behavior for many types of animals. Our field test included multiple prey species exposed in situ to multiple predator species and individuals to determine whether the prey species experienced predation patterns that were frequency dependent. The prey were seeds of three s...

In variable environments, organisms must have strategies to ensure fitness as conditions change. For plants, germination can time emergence with favourable conditions for later growth and reproduction (predictive germination), spread the risk of unfavourable conditions (bet hedging) or both (integrated strategies). Here we explored the adaptive value of within‐ and among‐year germination timing for 12 species of Sonoran Desert...

Early life‐cycle events play critical roles in determining the population and community dynamics of plants. The ecology of seeds and their germination patterns can determine range limits, adaptation to environmental variation, species diversity, and community responses to climate change. Understanding the adaptive consequences and environmental filtering of such functional traits will allow us to explain and predict ecological...

Phenotypic plasticity in seed provisioning is a widespread phenomenon in plant populations that is often manifested as environmentally induced maternal effects. Environmental maternal effects can be beneficial if they influence population dynamic functions of seeds in a way that increases fitness, such as escaping from crowding. Using the winter annual plant, Dithyrea californica , we studied the response of seed provisioning...

Under stressful circumstances, seed size has important consequences for germination, survival, and reproductive success; all of these are important components of plant fitness. This study investigates the relationship between seed size and fitness in the Sonoran Desert winter annual Dithyrea californica . This species represents a unique opportunity to study natural selection on seed size in the wild due to a serendipitous det...

In bet hedging, organisms sacrifice short‐term success to reduce the long‐term variance in success. Delayed germination is the classic example of bet hedging, in which a fraction of seeds remain dormant as a hedge against the risk of complete reproductive failure. Here, we investigate the adaptive nature of delayed germination as a bet hedging strategy using long‐term demographic data on Sonoran Desert winter annual plants. Us...

The saguaro cactus ( Carnegiea gigantea ) is one of the most iconic perennials in the Sonoran Desert. The ecological importance of this species has motivated studies that explored its physiological adaptations to deserts, factors controlling its recruitment and distribution, and changes in its population density and extent over time. The population of saguaros on Tumamoc Hill (Tucson, Arizona) is one of the best studied. Sagua...

How species respond to environmental variation can have important consequences for population and community dynamics. Temperature, in particular, is one source of variation expected to strongly influence plant performance. Here, we compared photosynthetic responses to temperature across a guild of winter annual plants. Previous work in this system identified a trade‐off between relative growth rate (RGR) and water‐use efficien...

Impacts of long‐term climate shifts on the dynamics of intact communities within species ranges are not well understood. Here, we show that warming and drying of the Southwestern United States over the last 25 years has corresponded to a shift in the species composition of Sonoran Desert winter annuals, paradoxically favoring species that germinate and grow best in cold temperatures. Winter rains have been arriving later in th...