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Riparian Ecology Summary

Good Essays

Richie Magallon
Riparian Ecology, Fall 2014
October 14, 2014
Literature Review #2 – Importance of Alder Phenology and Nitrogen Fixation in Riparian Zones Phenology is simply defined as the study of how the biological world times natural events. It is now scientifically understood that plants and animals alike take their seasonal cues from local weather. The phenology of all plant life is determined by sunlight, temperature, and water availability (in some cases precipitation, but in this case, streams). This review will focus mainly on the phenology of white alder (Alnus rhombifolia) and red alder (Alnus Rubra) and why they are able to fixate nitrogen in riparian ecosystems. Alder trees and shrubs are part of the birch family (Betulaceae) and are thought to play an essential role in riparian systems. Alder trees are flowering plants belonging to the genus Alnus which contains thirty species of Alder. While white alder trees are native to …show more content…

The flowers are produced in catkins. A catkin is a slim, cylindrical flower cluster, typically with no petals, that is usually wind-pollinated (anemophilous) although its seeds can also be water-pollinated (hydrophilous). Catkins are often drooping and are 1.25 to 4 inches (3-10 cm) long and are normally found near the end of a twig. Pollination occurs in early spring just before the leaves emerge, however, the alder retains its leaves most of the year in southern California. While White alder is closely related to the red alder (Alnus rubra) in most ways described above, the way to tell them apart is that they differ in the leaf margins being flat and not curled under. Both species, like other alders, are able to fix nitrogen, and tolerate infertile soils. Although strangely similar, both species do not tend to overlap although they seem to be important N fixers in the riparian areas that they reside

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