Comparing demography inferred from age vs. stage in a perennial plant.

Life history theories analyze and predict variation in vital rates, such as survival and reproduction, based on age. The age-from-stage method to derive age-specific vital rates from stage data was developed because age-specific data are rarely obtained for plants. Age-specific vital rates derived by this method might underestimate effects of age on vital rates, because the models assume that vital rates do not vary within stage classes.

Does masting scale with plant size? High reproductive variability and low synchrony in small and unproductive individuals.

Background And Aims: In a range of plant species, the distribution of individual mean fecundity is skewed and dominated by a few highly fecund individuals. Larger plants produce greater seed crops, but the exact nature of the relationship between size and reproductive patterns is poorly understood. This is especially clear in plants that reproduce by exhibiting synchronized quasi-periodic variation in fruit production, a process called masting.

Arctic and boreal plant species decline at their southern range limits in the Rocky Mountains.

Climate change is predicted to cause a decline in warm-margin plant populations, but this hypothesis has rarely been tested. Understanding which species and habitats are most likely to be affected is critical for adaptive management and conservation. We monitored the density of 46 populations representing 28 species of arctic-alpine or boreal plants at the southern margin of their ranges in the Rocky Mountains of Montana, USA, between 1988 and 2014 and analysed population trends and relationships to phylogeny and habitat.

Ability of matrix models to explain the past and predict the future of plant populations.

Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future.

Are dormant plants hedging their bets? Demographic consequences of prolonged dormancy in variable environments.

During the growing season, some individuals in perennial plant populations may remain alive belowground while others emerge. This phenomenon, known as prolonged dormancy, seems maladaptive, because prolonged dormancy delays growth and reproduction. However, prolonged dormancy may offer the benefit of safety while belowground, leading to the hypothesis that prolonged dormancy is a bet-hedging strategy.

How do plant ecologists use matrix population models?

Matrix projection models are among the most widely used tools in plant ecology. However, the way in which plant ecologists use and interpret these models differs from the way in which they are presented in the broader academic literature. In contrast to calls from earlier reviews, most studies of plant populations are based on < 5 matrices and present simple metrics such as deterministic population growth rates.

Pollen and water limitation in Astragalus scaphoides, a plant that flowers in alternate years.

Mast seeding is common in plant populations, but its causes have rarely been tested experimentally. We tested mechanisms of alternate-year flowering and fruit set in an iteroparous, bee-pollinated, herbaceous plant, Astragalus scaphoides, in semi-arid sagebrush steppe. Patterns of reproduction from 1986 to 1999 indicated that spring precipitation was a cue for synchronous flowering, and that increased pollination in high-flowering years was a fitness advantage of synchrony.

Rare plants are common where you find them.

Broad patterns in distribution and abundance can elucidate processes of evolution. A positive association between local abundance and the size of the geographic range has been demonstrated for closely related species across many taxa. This pattern is usually explained by assuming that species with smaller ranges are ecologically inferior (e.

Empirical models of pollen limitation, resource acquisition, and mast seeding by a bee-pollinated wildflower.

Synchronous mast seeding is increasingly recognized as common in plant populations. Recent theoretical models show that synchronous mast seeding could be a consequence of resource allocation and storage within individual plants, coupled by pollen limitation in low-flowering years. We used long-term population and weather data to parameterize models of flowering based on stored resources and pollen limitation in Astragalus scaphoides, a bee-pollinated plant that flowers in alternate years.

Autecology of the Endangered Plant Howellia Aquatilis; Implications for Management and Reserve Design.

Howellia aquatilis is an annual aquatic plant of ephemeral ponds. It is considered extirpated or endangered throughout its range in the United States Pacific Northwest. I studied populations in the Swan Valley of Montana to determine life history traits and ecological attributed in order to influence planning decisions on lands managed for multiple use.