Radiocarbon is an exceptionally useful tool for studying soil-respired CO₂, providing information about soil
carbon turnover rates, depths of production, and the biological sources of production through partitioning. Unfortunately, little
work has been done to thoroughly investigate the possibility of inherent biases present in current measurement techniques,
like those present...
We present a new method developed for measuring radiocarbon of methane (¹⁴CH₄) in ancient air samples
extracted from glacial ice and dating 11,000–15,000 calendar years before present. The small size (~20 μg CH₄ carbon), low
CH₄ concentrations ([CH₄], 400–800 parts per billion [ppb]), high carbon monoxide concentrations ([CO]), and low...
The interannual and intraseasonal variability of the North American monsoon is of great interest because a large proportion of the annual precipitation for Arizona and New Mexico arrives during the summer monsoon. Forty-one years of daily monsoon season precipitation data for Arizona and New Mexico were studied using wavelet analysis....
AIM:
Meta-community structure is a function of both local (site-specific) and regional (landscape-level) ecological factors, and the relative importance of each may be mediated by the dispersal ability of organisms. Here, we used aquatic invertebrate communities to investigate the relationship between local and regional factors in explaining distance decay relationships...
The ascomycete Geosmithia morbida and the walnut twig beetle Pityophthorus juglandis are associated with thousand
cankers disease of Juglans (walnut) and Pterocarya (wingnut). The disease was first reported in the western United States
(USA) on several Juglans species, but has been found more recently in the eastern USA in the...
Wildland fire affects both public and private resources throughout the United States. A century of fire suppression has contributed to changing ecological conditions and accumulated fuel loads. Managers have used a variety of approaches to address these conditions and reduce the likelihood of wildland fires that may result in adverse...
Hydrology is the main environmental filter in aquatic ecosystems and may result in shared tolerances and functional traits among species in disparate ecosystems. We analyzed the associations between taxonomic and functional facets of diversity within aquatic ecosystems (ponds vs. streams) across a hydroperiod gradient (1–365 d) to untangle the hydrologic...
National-scale analyses of fire occurrence are needed to prioritize fire policy and
management activities across the United States. However, the drivers of national-scale
patterns of fire occurrence are not well understood, and how the relative importance of human
or biophysical factors varies across the country is unclear. Our research goal...
Hydrology is a fundamental factor influencing ecosystem dynamics, life-history strategies, and diversity patterns in running-water habitats. However, it remains unclear how hydrology may structure the taxonomic and functional composition of communities, especially in systems with high spatiotemporal variability in flow. We examined invertebrate diversity from 7 desert streams in the...
Bighorn sheep (Ovis canadensis) were not known to live on Tiburón Island, the largest island in the Gulf of California and
Mexico, prior to the surprisingly successful introduction of 20 individuals as a conservation measure in 1975. Today, a stable
island population of ~500 sheep supports limited big game hunting...