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Keyword: ecosystem

Soil: The foundation of the ecosystem; effects of management activities on forest soils: Can we manage better?

Documents and Media Posted on: November 30, 2018
Since Aristotle considered soil in relation to plant nutrition (348-322 B.C.), knowledge of soils has made tremendous strides. The way we view soils has evolved from a focus on agriculture to modem views of soil from multiple perspectives, including that of soils as natural bodies, partitioners of water, a medium for plant growth, soils as ecosystems and ecosystem components, and soil as engineering materials. Document Type: Other Documents

Terrestrial vertebrates of mesquite bosques in southwestern North America [Chapter 11]

Publications Posted on: November 27, 2018
The major emphasis of this chapter is to address the species richness and population densities of land vertebrates in riparian mesquite bosques (woodlands). We find no single publication that lists vertebrates - amphibians, reptiles, birds, and mammals - of riparian mesquites of the Southwest lowlands. These vertebrates are listed for a few river valleys, such as the Santa Cruz River (Webb et al.

Breeding waterbirds of the Mexican portion of the Colorado River delta [Chapter 10]

Publications Posted on: November 27, 2018
Once a mighty and wild river with abundant wetlands, the section of the Colorado River flowing through Mexico has become a trickle ... whenever it flows. Most of the time since the 1960s, until recently, it did not and was completely dry. This brought tremendous changes in the "original" constitution and biological processes of the region, although they have not been fully investigated.

Evaluating riparian vegetation change in canyon-bound reaches of the Colorado River using spatially extensive matched photo sets [Chapter 9]

Publications Posted on: November 27, 2018
Much of what we know about the functional ecology of aquatic and riparian ecosystems comes from work on regulated rivers (Johnson et al. 2012). What little we know about unregulated conditions on many of our larger rivers is often inferred from recollections of individuals, personal diaries, notes, maps, and collections from early scientific surveys (Webb et al. 2007) and from repeat photography (Turner and Karpiscak 1980; Webb 1996).

Arizona as a watershed - then and now: Case studies of changed management of rivers and habitat in the lower Colorado River system [Chapter 8]

Publications Posted on: November 27, 2018
Prior to human development in the West, rivers flowed freely. Flows in the Colorado River varied greatly with season, with snowmelt runoff from the Rocky Mountains resulting in annual high flows (Topping et al. 2003). The large sediment loads historically found in the Colorado River, estimated to average 160,000,000 tons passing Yuma annually (LaRue 1916), have since caused Laguna Dam (fig.

Euro-american beaver trapping and its long-term impact on drainage network form and function, water abundance, delivery, and system stability [Chapter 7]

Publications Posted on: November 27, 2018
Euro-American (EA) beaver trapping was a regional and watershed-scale disturbance that occurred across the North American continent. This concentrated removal of beavers altered drainages by creating thousands of localized base-level drops as beaver dams failed and were not repaired.

Beavers, livestock, and riparian synergies: Bringing small mammals into the picture [Chapter 6]

Publications Posted on: November 27, 2018
Riparian ecosystems provide the anchor for their associated aquatic habitats and the structure for a unique assemblage of life found in these exceptionally productive ecosystems. Much of upland life also is tied to this zone, particularly in arid regions. For instance, on National Forest lands in the Southwest Region, 57 percent of all vertebrates occur in riparian ecosystems, but these systems make up

Unintended consequences: Tamarisk control and increasing threats to the southwestern willow flycatcher [Chapter 5]

Publications Posted on: November 27, 2018
It is well known that nonnative tamarisk (Tamarix parviflora, T. ramosissima, T. chinensis, and their hybrids; a.k.a. saltcedar) has replaced native riparian woodland vegetation along many streams in the arid Southwest over the last 100 years. Tamarisk can form extensive, dense monocultures and may alter not only the physical structure of the riparian woodland but also soil salinity and fire frequency (Sher 2013).

Invasion and restoration of western rivers dominated by Tamarix spp. [Chapter 4]

Publications Posted on: November 27, 2018
Scientists, land managers, government, and private institutions in the United States have given much attention to invasive control and restoration projects along western rivers; in the West, removal of Tamarix spp. (tamarisk, saltcedar) has been a primary focus of these projects (Dennison et al. 2009; González et al. 2017a; Harms and Hiebert 2006; Shafroth et al. 2008).

Impacts of interacting fire, climate, and hydrologic changes on riparian forest ecosystems in the Southwest [Chapter 3]

Publications Posted on: November 27, 2018
Changes in human populations, water use, climate, and related disturbances are impacting riparian ecosystems throughout the western United States. Nowhere is this more pronounced than in the arid American Southwest (Gutzler 2013; Molles et al. 1998; Webb et al. 2007).