Hiking up to the next plot…
Examines how plant life-history strategies, pollinator foraging behavior, and intraspecific competition shape population-level trait variation across alpine and subalpine flora.
Plant life history, foraging behavior, and population divergence are intertwined topics that help us understand why species look and act the way they do in mountain landscapes like the Gunnison Basin. Life history refers to the schedule of major events in an organism's life — when it grows, when it reproduces, how long it lives, and how quickly it ages. Ecologists often arrange species along a fast-slow continuum: fast-lived species mature quickly, reproduce often, and die young, while slow-lived species grow slowly, reproduce less frequently, and live longer. Where a species sits on this continuum shapes nearly every other aspect of its biology, including how vulnerable it is to environmental change.
Foraging behavior — the way animals search for and consume food — links plants and animals together in ecological networks. In subalpine meadows around Gothic, Colorado, bumblebees visiting wildflowers such as larkspur (Delphinium) and monument plant (Frasera) are a textbook example. The way bees move between flowers determines how pollen is transferred, which in turn shapes plant reproduction and, over generations, plant evolution. Small mammals like deer mice (Peromyscus) similarly influence plant populations by eating seeds and seedlings. Foraging is not random: animals respond to the spatial pattern of rewards such as nectar, and these decisions ripple outward into plant population dynamics.
Population divergence describes how groups of the same species, separated by distance or habitat, accumulate differences over time. In a topographically complex place like the Gunnison Basin, populations of a single wildflower species growing on different slopes or at different elevations may diverge in size, flowering time, or seed traits. Two concepts help here: intraspecific competition, where individuals of the same species compete for limited resources such as light, water, or nutrients, and evolvability, the capacity of a population to respond to selection. Together these forces govern whether mountain plant populations can adapt to local conditions and to a rapidly changing climate.
Much of the foundational research in this area emerged from a remarkable burst of student and faculty studies at RMBL in 1983 that examined plants, pollinators, and small mammals in the meadows around Gothic. Daggett and colleagues documented how nectar is distributed within larkspur inflorescences and how bumblebees adjust their foraging routes in response, providing an early window into how floral architecture shapes pollinator movement (Daggett et al., 1983). Head examined bumblebee foraging on the towering inflorescences of monument plant, linking queen bee behavior to the spatial structure of flower displays . Complementary work by Daggett and Gerut on deer mouse foraging in the laboratory helped establish how rodents make decisions about where and what to eat, with implications for seed predation in the field .
Genome-wide DArTseq scans of 268 individuals of Eucalyptus salubris, distributed along an aridity gradient in southwestern Australia, revealed cryptic...
On the plant side, Eiseman and colleagues quantified intraspecific competition in the small annual rockjasmine, Androsace septentrionalis, showing how density influences growth and survival within a single population (Eiseman et al., 1983). Jones mapped the distribution of bluebells, Mertensia fusiformis, documenting the kind of patchy, habitat-tied occurrence that sets the stage for population divergence in mountain wildflowers (Jones, 1983). Collectively, these early studies established the natural-history baseline that later, more quantitative work would build upon.
A central, broadly supported finding is that aging itself is a normal feature of wild populations, and that how fast a species ages depends on where it sits on the fast-slow life-history continuum. Drawing on twenty long-term, individual-based datasets of birds and mammals, Jones and colleagues showed that senescence — declines in survival and reproduction with age — is widespread in the wild and occurs about equally in both components of fitness (Jones et al., 2008). Importantly, mammals were found to age faster than similarly sized birds not because mammals are intrinsically different, but because they tend to have faster life histories for their body size (Jones et al., 2008). This reframing shifted the field away from taxonomic generalizations toward life-history-based explanations.
The RMBL-based studies of foraging and competition contributed a second strand of findings: that the fine-scale behavior of foragers and the local density of plants together generate strong selective pressures. Bumblebee movement responds to how nectar is dispersed within and among inflorescences, meaning that floral display traits feed back into pollination success (Daggett et al., 1983); (Head, 1983). Within plant populations, crowding measurably reduces individual performance, indicating that competition among neighbors is a real force shaping mountain wildflower demography (Eiseman et al., 1983).
Taken together, the early Gothic studies and the later comparative work converge on a single message: the schedule of life events, the behavior of foragers, and the local environment combine to drive both ecological dynamics in the short term and evolutionary divergence among populations in the long term.
Early work in the 1980s at RMBL established the natural-history and behavioral foundations for this area, while the 2008 senescence synthesis pushed the field toward quantitative, cross-species comparison. More recent directions, hinted at by the use of G-matrix analysis to pair plant population divergence data with estimates of evolvability, focus on whether the genetic architecture of traits actually constrains how mountain plant populations can respond to selection. This represents a shift from describing patterns of divergence to predicting them from underlying genetic variation.
The broader trajectory is toward integrating long-term demographic monitoring, behavioral observation, and quantitative genetics. Researchers are increasingly asking how climate-driven changes in snowmelt timing and growing-season length will reshape the fast-slow continuum for subalpine plants and the animals that depend on them.
Several important questions remain. How will the senescence patterns documented in vertebrates translate to long-lived subalpine plants, where individuals can persist for decades? Can measurements of evolvability in Gunnison Basin wildflower populations predict which species will keep pace with rapid climate change and which will lag behind? How do pollinator foraging decisions, which were first characterized at small scales in single meadows, scale up to influence gene flow and divergence across the basin? And what are the consequences of changing small-mammal populations for seed predation and plant recruitment in a warming world? Answering these questions will require linking the rich behavioral and demographic records collected at RMBL since the 1980s to modern genomic and modeling tools.
Daggett & Gerut (1983). A laboratory study of the foraging behavior of Peromyscus maniculatus. →
Daggett, et al. (1983). Nectar dispersion and bumblebee foraging in Delphinium nelsonii. →
Eiseman, et al. (1983). Intraspecific competition in Androsace septentrionalis. →
Head (1983). Bumblebee foraging patterns on Frasera speciosa inflorescences or, a monumental approach to Gothic queens. →
Jones (1983). Distribution of Mertensia fusiformis. →
Jones, O. R., et al. (2008). Senescence rates are determined by ranking on the fast-slow life-history continuum. Ecology Letters. →