Climate of Uruguay

The whole of Uruguay is officially classified as a CFA climate according to the Koppen classification system, meaning it is temperate with high humidity and warm summers, as previously illustrated in Blog 1.

CFA climates are indicated in green. Image obtained from Wikipedia,
information regarding climate confirmed from instructor slides.

Atmospheric conditions influencing climate in the region are dominated by the high pressure cell. The proximity of the Atlantic Ocean contributes to the climate's humidity. Urban heat island effects are minimal although anthropogenic influences are discussed below.

Soil Types
There are a variety of soil types across Uruguay that determine the types of plants that can flourish in different areas. These plants in turn impact the climate and types of organisms. Furthermore, soil conditions influence areas of anthropogenic impact (ie soils suitable for agriculture and grazing) [4]. Pellic Vertisols and lithosols cover most of the country. These soil types offer good drainage and do not hold water too well [1]. Mollic Planosols in much of the country are rich in organic matter and support crops. The relativly flat topography and steady precipitation levels prevent major soil erosion and allow for the accumulation of organic matter.

Group I soils are vertisols and lithosols. Group III and IV are planosols.
image from http://www.fao.org/ag/AGP/AGPC/doc/Counprof/uruguay/Fig4.htm 

Plants of Uruguay


Herbaceous and grass plants dominate the native vegetation of the region. Larger native trees occur in small forest clusters and grow particularly near rivers.

Piptochaetium montevidense. A grass common
in Uruguay, now considered an invasive species
in Australia
Photo from [2]

Celtus Spinosa. A tree that commonly grows in the proximity of
rivers. [3]

Phytolacca Dioica. A variety of herbaceous
vegitation found in Uruguay that may also
grow in a tree habit [5].

The burrowing owl, pictured above, is native to Uruguay.
It has adapted to life within the grasslands and burrows
in the ground instead of nesting within trees since taller
foliage is a limited resource.

Since population expansion, native forests were cleared to make way for agricultural lands. However several native tree species were planted in urban areas as ornamental varieties. [4]

Citharexylum montevidense. Known only as
an ornamental tree [3]. Despite clearing natural
foest for agriculture, ornamental trees have seen
an increase with urbanization.

Currently there are few introduced plants from other similar climates, most notably the Eucalyptus.

Paleoclimate


Because of the flat topography and high humidity in the region, sediments are particularly well preserved in Uruguay and can give an accurate view of previous climate. Lake deposits indicate similar plant species in the region previously with roughly the same climate. Recent (ten to twenty years ago) data does not suggest any significant trends in temperature change within Uruguay. However, varying sea levels and meandering rivers have altered the status of water bodies. Data that goes as far back as the Holocene suggests that Uruguay dries out from its characteristic perennially humid state during cold periods, particularly during the last smaller ice age [6].

Isotopic analysis of lake sediments has revealed human contributions to local climate recently. Since the increased demand for agriculture and from minor contributions from urbanization, Uruguay has seen an increase in eutrophication. Increased levels of nitrogen in sediments are attributed to fertilizer runoff. Eutrophication can affect local climate by increasing the amount of carbon dioxide released during fall and spring turnover. Additionally, high concentrations of algae absorb greater amounts of sunlight and may increase lake temperatures by limiting reflectivity [7].



References
[1] http://www.fao.org/ag/AGP/AGPC/doc/Counprof/uruguay/uruguay2.htm
[2] http://www.zhiwutong.com/tu/bp/p/piptochaetium%20montevidense%2002.JPG
[3] http://micol.fcien.edu.uy/flora/uy_flora.htm
[4] http://www.worldwildlife.org/wildworld/profiles/terrestrial/nt/nt0803_full.html
[5] http://florasilvestre.es/mediterranea/Phytolaccaceae/Phytolacca_dioica2.jpg
[6] http://pages-142.unibe.ch/products/newsletters/2009-3/Special%20section/Science%20Highlights/Garcia-Rodriguez_etal_2009-3(115-117).pdf
[7] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2266883/