A ciénega (also spelled ciénaga) is a wetland system unique to the American Southwest. Ciénagas are alkaline, freshwater, spongy, wet meadows with shallow-gradient, permanently saturated soils in otherwise arid landscapes that often occupy nearly the entire widths of valley bottoms. That description satisfies historic, pre-damaged ciénagas, although few can be described that way now. Incised ciénagas are common today. Ciénagas are usually associated with seeps or springs, found in canyon headwaters or along margins of streams. Ciénagas often occur because the geomorphology forces water to the surface, over large areas, not merely through a single pool or channel. In a healthy ciénaga, water slowly migrates through long, wide-scale mats of thick, sponge-like wetland sod. Ciénaga soils are squishy, permanently saturated, highly organic, black in color or anaerobic. Highly adapted sedges, rushes and reeds are the dominant plants, with succession plants—Goodding's willow, Fremont cottonwoods and scattered Arizona walnuts—found on drier margins, down-valley in healthy ciénagas where water goes underground or along the banks of incised ciénagas.
Ciénagas are not considered true swamps due to their lack of trees, which will drown in historic ciénagas. However, trees do grow in many damaged or drained ciénagas, making the distinction less clear. (Full article...)
Credit: Lynn Betts, USDA Natural Resources Conservation Service
Topsoil is the upper, outermost layer of soil, usually the top 2 inches (5.1 cm) to 8 inches (20 cm). It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Pictured: Terraces, conservation tillage, and conservation buffers save soil, control erosion and improve water quality on this Iowa farm. 1999.
Image 3A generalised graph of a predator-prey population density cycle (from Community (ecology))
Image 4Sequence of a decomposing pig carcass over time (from Ecosystem)
Image 5Global oceanic and terrestrial phototroph abundance, from September 1997 to August 2000. As an estimate of autotroph biomass, it is only a rough indicator of primary production potential and not an actual estimate of it. (from Ecosystem)
Image 13An Antarctic rock split apart to show endolithic lifeforms showing as a green layer a few millimeters thick (from Habitat)
Image 14A simple trophic cascade diagram. On the right shows when wolves are absent, showing an increase in elks and reduction in vegetation growth. The left one shows when wolves are present and controlling the elk population. (from Community (ecology))
Image 17a) A trophic pyramid showing the different trophic levels in a community. b) A food web of the same community (from Community (ecology))
Image 18Wetland habitat types in Borneo (from Habitat)
Image 19Dense mass of white crabs at a hydrothermal vent, with stalked barnacles on right (from Habitat)
Image 20Few creatures make the ice shelves of Antarctica their habitat, but water beneath the ice can provide habitat for multiple species. Animals such as penguins have adapted to live in very cold conditions. (from Habitat)
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The peacock flounder can change its pattern and colours to match its environment.
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the battledress of a modern soldier, and the leaf-mimic katydid's wings. A third approach, motion dazzle, confuses the observer with a conspicuous pattern, making the object visible but momentarily harder to locate, as well as making general aiming easier. The majority of camouflage methods aim for crypsis, often through a general resemblance to the background, high contrast disruptive coloration, eliminating shadow, and countershading. In the open ocean, where there is no background, the principal methods of camouflage are transparency, silvering, and countershading, while the ability to produce light is among other things used for counter-illumination on the undersides of cephalopods such as squid. Some animals, such as chameleons and octopuses, are capable of actively changing their skin pattern and colours, whether for camouflage or for signalling. It is possible that some plants use camouflage to evade being eaten by herbivores.
Military camouflage was spurred by the increasing range and accuracy of firearms in the 19th century. In particular the replacement of the inaccurate musket with the rifle made personal concealment in battle a survival skill. In the 20th century, military camouflage developed rapidly, especially during the First World War. On land, artists such as André Mare designed camouflage schemes and observation posts disguised as trees. At sea, merchant ships and troop carriers were painted in dazzle patterns that were highly visible, but designed to confuse enemy submarines as to the target's speed, range, and heading. During and after the Second World War, a variety of camouflage schemes were used for aircraft and for ground vehicles in different theatres of war. The use of radar since the mid-20th century has largely made camouflage for fixed-wing military aircraft obsolete. (Full article...)
Exequiel Ezcurra (born March 21, 1950, Buenos Aires, Argentina) is a Mexican plant ecologist and conservationist. His highly interdisciplinary work spans desert plant ecology, mangroves, island biogeography, sea birds, fisheries, oceanography, and deep-sea ecosystems.
Between 2008 and 2019 he was director of the University of California Institute for Mexico and the United States (UC MEXUS). He is now Professor of Plant Ecology at UC Riverside. (Full article...)
To secure our environmental legacy for future generations, we must find ways to reconcile humanity more satisfactorily with the natural systems upon which all human life and civilizations depend. We must recognize that the natural systems of which we are part have an intrinsic worth transcending narrow utilitarian values. They must be preserved for their own sake. No philosopher or religious thinker has been more sensitive to this intimate relationship between humanity and nature than St. Francis of Assisi. The powerful contemporary environmental tradition of preservation, of reverence for wilderness and protection for all living things - the ideal that sees, as John Muir said, ‘in God’s wildness... the hope of the world’ - virtually began with St. Francis.
... paleoecology uses data from fossils and subfossils to reconstruct the ecosystems of the past? It involves the study of fossil organisms and their associated remains, including their life cycle, living interactions, natural environment, and manner of death and burial to reconstruct the paleoevironment.