Amount of vegetation and water: Stream Versus Arid Mountainside

By comparing the plants present within the arid portions of the Altadena mountains, with the areas where a stream is present, one thing that I found was just the general abundance of vegetation. Within the water laden areas supplied by the stream, the abundance of trees is considerably greater. Conversely, along the arid regions that I surveyed, the vegetation consisted mostly of shrubs and bushes. One possible reason that may have accelerated this difference is the long standing drought. According to Suarez, M., & Sasal, Y in “Drought-Induced Mortality..”, “when drought is severe enough to produce massive die-offs, the consequences for forest composition can be considerable. For example, in semi-arid woodlands, drought may cause massive die-offs that contribute to ecotonal shifts along a moisture gradient, and accelerate shrub invasions”. And because shrubbery is known to be a factor in wildfire risk and prevalence, the recent abundance that we have been witnessing of wildfires, may be further explained to the abundance of certain shrubs. And according to Elizabeth Shogren, “The [California] fires gained intensity as they ran through ...slopes covered with chaparral, manzanita and other shrubs. Chaparral “is designed to burn pretty hot,” says Jeffrey Kane, an associate professor of fire ecology at Humboldt State. And both forests and shrublands were overgrown, choked with underbrush and small trees that provided a continuous source of fuel as the fires moved across the hilly terrain.”. This is concerning, as I found that a major species present within the dry areas was chaparral yucca.

Sources:
Suarez, M., & Sasal, Y. (2012). Drought-induced mortality affects understory vegetation: release after death. Ecological Research, 27(4), 715-724. doi:10.1007/s11284-012-0945-5
http://www.hcn.org/articles/wildfire-what-role-did-wildlands-play-in-californias-wine-country-fires

Publicado el diciembre 10, 2017 09:46 TARDE por _ben_