Factors Altitudinal zonation

1 factors

1.1 temperature
1.2 humidity
1.3 soil composition
1.4 biological forces
1.5 solar radiation
1.6 massenerhebung effect
1.7 other factors

factors

heating of solids, sunlight , shade in different altitudinal zones (northern hemisphere)

a variety of environmental factors determines boundaries of altitudinal zones found on mountains, ranging direct effects of temperature , precipitation indirect characteristics of mountain itself, biological interactions of species. cause of zonation complex, due many possible interactions , overlapping species ranges. careful measurements , statistical tests required prove existence of discrete communities along elevation gradient, opposed uncorrelated species ranges.

temperature

decreasing air temperature coincides increasing elevation, directly influences length growing season @ different altitudes of mountain. mountains located in deserts, extreme high temperatures limit ability of large deciduous or coniferous trees grow near base of mountains. in addition, plants can sensitive soil temperatures , can have specific elevation ranges support healthy growth.

humidity

the humidity of zones, including precipitation levels, atmospheric humidity, , potential evapotranspiration, varies altitude , significant factor in determining altitudinal zonation. important variable precipitation @ various altitudes. warm, moist air rises windward side of mountain, air temperature cools , loses capacity hold moisture. thus, greatest amount of rainfall expected @ mid-latitudes , can support deciduous forest development. above elevation rising air becomes dry , cold, , discourages tree growth. though rainfall may not significant factor mountains, atmospheric humidity or aridity can more important climatic stresses affect altitudinal zones. both overall levels of precipitation , humidity influence soil moisture well. 1 of important factors control lower boundary of encinal or forest level ratio of evaporation soil moisture.

soil composition

the nutrient content of soils @ different altitudes further complicates demarcation of altitudinal zones. soils higher nutrient content, due higher decomposition rates or greater weathering of rocks, better support larger trees , vegetation. altitude of better soils varies particular mountain being studied. example, mountains found in tropical rainforest regions, lower elevations exhibit fewer terrestrial species because of thick layer of dead fallen leaves covering forest floor. @ latitude more acidic, humose soils exist @ higher elevations in montane or subapline levels. in different example, weathering hampered low temperatures @ higher elevations in rocky mountain of western united states, resulting in thin coarse soils.

biological forces

in addition physical forces, biological forces may produce zonation. example, strong competitor can force weaker competitors higher or lower positions on elevation gradient. importance of competition difficult assess without experiments, expensive , take many years complete. however, there accumulating body of evidence competitively dominant plants may seize preferred locations (warmer sites or deeper soils). 2 other biological factors can influence zonation: grazing , mutualism. relative importance of these factors difficult assess, abundance of grazing animals, , abundance of mycorrhizal associations, suggests these elements may influence plant distributions in significant ways.

solar radiation

light significant factor in growth of trees , other photosynthetic vegetation. earth’s atmosphere filled water vapor, particulate matter, , gases filter radiation coming sun before reaching earth’s surface. hence, summits of mountains , higher elevations receive more intense radiation basal plains. along expected arid conditions @ higher elevations, shrubs , grasses tend thrive because of small leaves , extensive root systems. however, high elevations tend have more frequent cloud cover, compensates of high intensity radiation.

massenerhebung effect

the physical characteristics , relative location of mountain must considered in predicting altitudinal zonation patterns. massenerhebung effect describes variation in tree line based on mountain size , location. effect predicts zonation of rain forests on lower mountains may mirror zonation expected on high mountains, belts occur @ lower altitudes. similar effect exhibited in santa catalina mountains of arizona, basal elevation , total elevation influence altitude of vertical zones of vegetation.

other factors

in addition factors described above, there host of other properties can confound predictions of altitudinal zonations. these include: frequency of disturbance (such fire or monsoons), wind velocity, type of rock, topography, nearness streams or rivers, history of tectonic activity, , latitude.