Filters: partyWithName: Belnap, Jayne (X) > partyWithName: Evans, R David (X)
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Invasion by the C3 annual grass Bromus tectorum has significantly increased the amount of relatively low quality (high lignin:nitrogen) plant litter deposited in arid Colorado Plateau grasslands. Our objectives were to determine what effects these changes have on microbial utilization of carbon (C) and nitrogen (N). We measured net C and N mineralization, and the ?13C of bulk organic matter, mineralized C, and bacterial fatty acids from soils of invaded and non-invaded C3 (Stipa hymenoides) and C4 (Hilaria jamesii) native grasslands. Carbon mineralization was greater in invaded compared to non-invaded sites (1.25 +/- 0.09 and 1.52 +/- 0.18 g CO2-C kg-1 soil h-1 respectively). Rates of net inorganic N mineralization...
Global change caused by anthropogenic activities may significantly modify the abundance, structure, and function of biological soil crusts. The components of global change can be grouped into (1) those that impact discreet sites but are occurring on a global scale, such as land-use change and invasive species, and (2) those that alter atmospheric chemistry resulting in changes in CO2 concentration, UV radiation, temperature, and precipitation (Vitousek 1994). In this chapter we will examine how landuse change, invasive species, elevated atmospheric CO2, increased UV radiation, and climate change may affect biological soil crusts and the ecosystems which they inhabit. Published in Biological Soil Crusts: Structure,...
Categories: Publication;
Types: Book Citation,
Citation;
Tags: Biological Soil Crusts: Structure, Function, and Management,
Springer-Verlag
The introduction of nonnative plant species may decrease ecosystem stability by altering the availability of nitrogen (N) for plant growth. Invasive species can impact N availability by changing litter quantity and quality, rates of N2-fixation, or rates of N loss. We quantified the effects of invasion by the annual grass Bromus tectorum on N cycling in an arid grassland on the Colorado Plateau (USA). The invasion occurred in 1994 in two community types in an undisturbed grassland. This natural experiment allowed us to measure the immediate responses following invasion without the confounding effects of previous disturbance. Litter biomass and the C:N and lignin:N ratios were measured to determine the effects on...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Bromus tectorum,
Canyonlands National Park,
Ecological Applications,
N mineralization,
Utah,
Biological soil crusts, composed primarily of photosynthetic cyanobacteria, algae, lichens and mosses, play a key role in many ecosystem functions of semi-arid and arid ecosystems around the world (Belnap and Lange 2001). They often cover plant interspaces in undisturbed areas (Kleiner and Harper 1972) and thus can constitute 70% or more of the living ground cover (Belnap 1995). These soil crusts are critical in the stabilization of soils and reduce both wind and water erosion (Belnap and Gillette 1997, 1998). They influence many processes that determine soil fertility, including carbon and nitrogen fixation, dust capture, and mineral chelation. They are often the dominant source of nitrogen (N) in desert ecosystems...
Categories: Publication;
Types: Citation
Anthropogenic activity is causing dramatic changes in the nitrogen (N) cycle in many ecosystems. Most research has focused on the increase in N input caused by atmospheric deposition and invasion of N-fixing species, and on their effects on resource availability and species composition. However, in contrast to many ecosystems experiencing large increases in N input, many arid ecosystems are experiencing loss of nutrients due to land-use change. An important component of many arid ecosystems on a worldwide basis is the microbiotic crust, a biological soil crust composed of lichens, cyanobacteria, mosses, and algae. Nitrogen fixation by lichens and cyanobacteria comprising the crust is the primary source of N input...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Canyonlands National Park,
Ecology,
Utah,
cryptogamic crusts,
land-use change,
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