Amy L. Angert results 17
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Linking Climate and Demography to Predict Population Dynamics and Persistence Under Global ChangeNARA Subscribed
Predicting the effects of climate change on plant and animal populations is an urgent challenge for understanding the fate of biodiversity under global change. At the surface, quantifying how climate drives the vital rates that underlie population dynamics appears simple, yet many decisions are required to connect climate to demographic data. Competing approaches have emerged in the literature with little consensus around best...
Organisms have evolved diverse adaptive strategies to cope with environmental fluctuations. Slow‐growing long‐lived species tend to exhibit low temporal variability in population growth (strongly buffered demographically), whereas fast‐growing short‐lived species optimize growth in favorable years (weakly buffered). These patterns set up the expectation that differentiation in demographic buffering may reduce disparities in lo...
Range expansion is both slower and more variable with rapid evolution across a spatial gradient in temperatureNARA Subscribed
Rapid evolution in colonising populations can alter our ability to predict future range expansions. Recent theory suggests that the dynamics of replicate range expansions are less variable, and hence more predictable, with increased selection at the expanding range front. Here, we test whether selection from environmental gradients across space produces more consistent range expansion speeds, using the experimental evolution o...
As ongoing climate change drives suitable habitats to higher elevations, species ranges are predicted to follow. However, observed range shifts have been surprisingly variable, with most species differing in rates of upward shift and others failing to shift at all. Disturbances such as fires could play an important role in accelerating range shifts by facilitating recruitment in newly suitable habitats (leading edges) and remo...
The role of demographic compensation in stabilising marginal tree populations in North AmericaNARA Subscribed
Demographic compensation—the opposing responses of vital rates along environmental gradients—potentially delays anticipated species’ range contraction under climate change, but no consensus exists on its actual contribution. We calculated population growth rate (λ) and demographic compensation across the distributional ranges of 81 North American tree species and examined their responses to simulated warming and tree competiti...
Eco‐evolutionary dynamics of range expansionNARA Subscribed
Understanding the movement of species’ ranges is a classic ecological problem that takes on urgency in this era of global change. Historically treated as a purely ecological process, range expansion is now understood to involve eco‐evolutionary feedbacks due to spatial genetic structure that emerges as populations spread. We synthesize empirical and theoretical work on the eco‐evolutionary dynamics of range expansion, with emp...
Aim Geographical ranges largely reflect the projection of species’ environmental niches onto the landscape, but dispersal limitation can cause ranges to fall short of niche limits. Understanding the prevalence of niche and dispersal limitation is a fundamental problem in ecology and biogeography, and it is relevant in predicting climate‐driven range shifts. Dispersal limitation could also cause widely used ecological niche mod...
Correlative species distribution models are based on the observed relationship between species’ occurrence and macroclimate or other environmental variables. In climates predicted less favourable populations are expected to decline, and in favourable climates they are expected to persist. However, little comparative empirical support exists for a relationship between predicted climate suitability and population performance. We...
A synthesis of transplant experiments and ecological niche models suggests that range limits are often niche limitsNARA Subscribed
Global change has made it important to understand the factors that shape species’ distributions. Central to this area of research is the question of whether species’ range limits primarily reflect the distribution of suitable habitat (i.e. niche limits) or arise as a result of dispersal limitation. Over‐the‐edge transplant experiments and ecological niche models are commonly used to address this question, yet few studies have...
Identifying the paths leading to variation in geographical range size in western North American monkeyflowersNARA Subscribed
Aim Closely related species can vary tremendously in size of geographical range, yet the causes of such variation are poorly understood. Prominent hypotheses about range size emphasize effects of niche properties and habitat connectivity via the amount and occupancy of suitable habitat, respectively. Previous studies have examined single hypotheses in isolation; however, we assessed the relative importance of these effects alo...
Variation in photosynthetic response to temperature in a guild of winter annual plantsNARA Subscribed
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...
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