Responses of plant populations and communities to environmental changes of the late Quaternary

Abstract

The environmental and biotic history of the late Quaternary represents a critical junction between ecology, global change studies, and pre-Quaternary paleobiology. Late Quaternary records indicate the modes and mechanisms of environmental variation and biotic responses at timescales of 101–104 years. Climatic changes of the late Quaternary have occurred continuously across a wide range of temporal scales, with the magnitude of change generally increasing with time span. Responses of terrestrial plant populations have ranged from tolerance in situ to moderate shifts in habitat to migration and/or extinction, depending on magnitudes and rates of environmental change. Species assemblages have been disaggregated and recombined, forming a changing array of vegetation patterns on the landscape. These patterns of change are characteristic of terrestrial plants and animals but may not be representative of all other life-forms or habitats. Complexity of response, particularly extent of species recombination, depends in part on the nature of the underlying environmental gradients and how they change through time. Environmental gradients in certain habitats may change in relatively simple fashion, allowing long-term persistence of species associations and spatial patterns. Consideration of late Quaternary climatic changes indicates that both the rate and magnitude of climatic changes anticipated for the coming century are unprecedented, presenting unique challenges to the biota of the planet.

Geographical and climatic limits of needle types of one‐ and two‐needled pinyon pines

“…This ‘potential climate range’ for each plant species (Jackson & Overpeck, 2000) acknowledges that ecological variables other than climate (i.e. fire, history, substrate, succession, migration) can be important in determining a species’ limits.…”

Marked genetic divergence among sky island populations ofSedum lanceolatum(Crassulaceae) in the Rocky Mountains

“…Biogeographic responses of flora to recurrent cycles of climate change greatly impact the evolution of a species (Stebbins, 1984) and that response is species dependent (Jackson and Overpeck, 2000), based on seed-dispersal abilities, pollination strategies, life span, and whether the species is asexual, a self-pollinator, or outcrossing. Several life history traits in S. lanceolatum (Clausen, 1975), including a long-lived perennial habit, slow growth, local outcrossing through insect pollination, vegetative reproduction, and limited or short-distance seed dispersal, undoubtedly influenced the high degree of iso-lation and spatial stability of this species.…”

Are fundamental niches larger than the realized? Testing a 50-year-old prediction by Hutchinson

“…Furthermore, limited climate availability [6] is also expected to reduce N F to a smaller realized niche ( N R ). On the other hand, mutualistic interactions should have the opposite effect [3, 7–10]. …”

“…Although old and superficially obvious, Hutchinson’s idea has seldom been tested, partially because the concept of “niche” originally combined many types of variables that caused not only terminological imprecision [11] but also serious complications at measuring the fundamental niche, mostly when the variables used to define it are resources consumed by the species in question [11]. Here, we use the Grinnellian niche concept [10, 12] in which niche space is defined using non-interactive conditions (i.e., scenopoetic variables [13]); specifically, we use one climatic variable (average monthly temperature) measured at every cell of a discrete geographic grid of the planet ( G ). Although we restrict our example to a niche defined by a single scenopoetic variable, all the computations can be performed using more variables, as we show in S1 File, Section 2: Estimation of niches in two dimensions.…”