1. Resource competition is thought to be important in controlling zooplankton population dynamics and structuring zooplankton communities. Resource competition requires that resources are limiting. Ten field experiments were conducted to determine the presence and intensity of resource limitation of

The evolution of flowering phenology has most often been examined in light of one set of organisms, namely pollinators. However, the patterns of flowering phenology observed in nature are likely to reflect evolutionary compromises in response to a variety of selective forces. Two of the most importa

The range of Opuntia imbricata (Haw.) DC., together with data from 250 weather stations, was mapped revealing that the cactus is essentially confined to a region receiving 28 to 48 cm annual precipitation and experiencing mean January temperatures above --1'C. The distribution of the cactus was quan

Abstract Water is a critical resource that causes significant challenges to inhabitants of the western United States. These challenges are likely to intensify as the result of expanding population and climate-related changes that act to reduce runoff in areas of complex terrain. To better understand

Over the past two decades, thermochronological studies have greatlyincreased our knowledge of the Cenozoic evolution of the Colorado Plateau(western United States). There has been particular interest in the southwesternpart of the plateau, leading to debate regarding the timing of uplift andfluvial

A theory of macroecology based on the maximum information entropy (MaxEnt) inference procedure predicts that the log-log slope of the species-area relationship (SAR) at any spatial scale is a specified function of the ratio of abundance, N(A), to species richness, S(A), at that scale. The theory thu

The distance at which animals move away from threats, flight initiation distance (FID), is often used to study antipredator behaviour and risk assessment. Variation in FID is explained by a variety of internal and external biotic and physical factors, including anthropogenic activities. Most prior s

After maintaining elevations near sea level for over 500 million years, the Colorado Plateau (CP) has a present average elevation of 2 km. We compute new receiver function images from the first dense seismic transect to cross the plateau that reveal a central CP crustal thickness of 42–50 km thinnin

In August 2009, President Barack Obama traveled to Grand Junction, Colorado, touting that community's health care system as a model for the provision of low-cost, high-quality care. According to the Dartmouth Atlas of Health Care, average per capita Medicare spending in Grand Junction was $6,599 in

Growth and adult survival rates were estimated for the endangered Colorado squawfish Ptychocheilus lucius inhabiting the upper Colorado River by using data from fish captured during 1990–1995. Mean annual growth rates of fish aged 3–6 years ranged from 32.2 (age 6) to 82.0 (age 3) mm/year. Growth ra

Research Article| February 01, 1985 Revised interpretation of the age of allochthonous rocks of the Uncompahgre Formation, Needle Mountains, Colorado B. J. TEWKSBURY B. J. TEWKSBURY 1Department of Geology, Hamilton College, Clinton, New York 13323 Search for other works by this author on: GSW Google

AbstractDams have reduced distribution of the endangered Colorado pikeminnow Ptychocheilus lucius in the upper Colorado River basin: low‐head diversion dams blocked upstream passage and large dams inundated free‐flowing segments and cooled downstream reaches with deep‐water releases. To date, range

The fate of natural populations is mediated by complex interactions among vital rates, which can vary within and among years. Although the effects of random, among-year variation in vital rates have been studied extensively, relatively little is known about how periodic, nonrandom variation in vital

In Frasera speciosa , a long‐lived monocarpic gentian from the Colorado Rocky Mountains, leaves are preformed two to three yr in advance of their appearance above ground. Initiation of a flower stalk may begin as long as three yr before it becomes fully developed during a plant's final year. Whorls

PHYSIOLOGIcAL homeostasis is maintained with energy that a bird must extract from its environment. Effective investment of the bird's time in exchange for the necessary energy must be the objective of maintenance strategy. If the rate of intake is less than the metabolic rate over a period of time,

A year-round study was conducted in the Colorado River, USA, to examine microdistributions and feeding habits of the filter-feeding Trichoptera (caddisflies) em Arctopsyche grandis /em , em Brachycentrus occidentalis /em and em Hydropsyche cockerelli /em . Only one significant relationship was found