aves Flora Fauna Ecosistema

Patagonian Ecosystems

Argentine Patagonia, also known as the Patagonian region, is one of Argentina's geographical regions. It is the largest in all Argentina and is sometimes simply called "The South". This area contains a number of provinces and natural features that are unique in the world. The most important cities are Neuquén, in the upper Río Negro valley, Comodoro Rivadavia, on the Atlantic coast, and San Carlos de Bariloche, which lies close to the Andes Mountain Range.

Dry Forests

These are situated between 200 and 1200 masl, (depending on the latitude). Annual precipitation in these forests is around 1000 mm, although in the most easterly forests this may be as low as 600mm. The dominant species vary according to the area, and especially the soil. On the valley floors and in deeper soils with a higher volcanic ash content Nothofagus species predominate: Antarctic decidious beech (N. antarctica), raulí beech (N. alpina), roble beech (N. obliqua) and evergreen beech (N. dombeyi). On steep hillsides with rockier or sandier ground, the cordillera cypress (Austrocedrus chilensis) and the monkey-puzzle tree (Araucaria araucana) are the species most commonly found.

The underbrush varies considerably in its makeup: it is usually dense where there is more humidity and deeper soil. Here, species of Berberis (box-leafed barberry and holly-leafed barberry) thrive, as do laura (Schinus patagonicus), maqui (Aristotelia chilensis), chilcas (Baccharis spp.) and colihue cane (Chusquea culeou).

In drier areas and where the soil is shallower there is greater diversity of low shrubs and plants.

High Altitude Forests

These are generally situated above 1200 masl and reach as high as 1800 masl, growing alongside the high Andean vegetation. Annual precipitation in these forests varies between 1500 and 3000 mm (with more precipitation at higher altitudes), and much of this falls in the form of snow. The predominant woody species is high deciduous beech, (Nothofagus pumilio), which tends to be replaced by the Antarctic low beech (Nothofagus antarctica) where the soil is very humid.

With altitude, both species adopt a stunted, shrubby growth style, even taking on a creeping form in flat areas with a lot of snow. The barberries are common in the underbrush, as well as other shrubby species. Below 1400m the coverage of colihue cane (Chusquea culeou) also tends to be dense. At higher altitudes, the amancay (Alstroemeria aurea) is a common sight amongst the plant life of these forests.


These are situated between 200 masl (in Lago Puelo, Chubut) and 100 masl. In Argentina they represent a simplified or impoverished expression of the Valdivian Forest of Chile. Annual precipitation in these forests is high (around 2000 mm) and, in contrast to what happens in other forest communities in the area, it is distributed with a certain regularity throughout the year, due to the humid influence of the Pacific Ocean. Moreover, this influence moderates the extreme temperatures. A high diversity of tree species coexists in these forests, reaching over 10 different species per hectare in the most westerly forests. Some of the most characteristic species, in addition to the evergreen beech (which tends to dominate), are the lahuán (Fitzroya cupressoides), the mañíos (male, Podocarpus nubigena, and (female, Saxegothaea conspicua), the tineo (Weinmannia trichosperma), the fuinque (Lomatia ferruginea), the avellano (Gevuina avellana), the lingue (Persea lingue) and the hua-huán (Laureliopsis philippiana).

All of these species are perennial and have characteristics similar to tropical species. Also common in this type of community are the climbing species (several of which have red flowers), ferns and mosses. Decomposing organic matter abounds, although the shadiness of the forest determines that herbaceous species are not common.


Ecotonal Scrub

This community is typical of the lower areas of hillsides and mountainsides and wide valleys with little water. The altitude varies between 600 and 1000 masl and annual precipitations are less than 1500mm. The dominant species in these scrublands depend on exposure to sun and the soil (generally sandy or rocky). In the more humid zones with deeper soil, trees or shrubs of up to five metres in height predominate, such as radales (Lomatia hirsuta), lauras (Schinus patagonicus), maitenes (Maytenus boaria), chacayes (Discaria serratifolia) and retamos (Diostea juncea). The barberries (Berberis spp.), palo piche (Fabiana imbricata) and the chilcas and huautros (Baccharis spp.) form a shrubby layer less than three metres in height.

These scrublands have been greatly disturbed by anthropic activities, (tree felling, cattle, etc.) and therefore the larger plants are more and more spread out, providing suitable conditions for the establishment of creeping shrubs such as mosaiquillo, (Baccharis magellanica), subshrubs (Senecio spp. and Acaena spp.) and various species of plants, such as invasive shrubs like the sweet briar (Rosa rubiginosa).

Shrub steppe

This community occupies dry zones of Patagonia (usually with less than 700 mm annual precipitation). There is much variation in altitude and in the plant species found here. In general the larger plants of the shrub steppe are no more that one and a half metres in height and are widely dispersed. It is common to find shrubs or subshrubs in cushion form, such as neneos (Mulinum spinosum), abrojos (Acaena spp.) and espinos (Discaria articulata). One group of subshrubs which has diversified greatly is the senecio group (Senecio spp.), some of which are known as charcao.

In contrast to the plant communities growing in more favourable environmental conditions, in the shrub steppe annual plants are common, and they thrive in the shelter of the shrubs and subshrubs. Due to the strength of the winds, the sandy, rocky soil and low rainfall, invasive species rarely become established here, although the cattle do contribute with the dissemination of sweet briar (Rosa rubiginosa).

Herbaceous steppe

This community is similar to the shrub steppe in terms of low precipitation levels and exposure to strong westerly winds. However, in contrast to that community, in the herbaceous steppe the predominant species are graminaceous plants (grasses) with a compact, hemispherical structure, known as coirones, which belong to various different genera (Poa spp., Festuca spp. and Jarava spp.). These tend to be the only plants capable of tolerating the harsh environmental conditions, in addition to sheep and goat activity.

Shrubs and subshrubs are less abundant, although sometimes the non-edible charcaos (Senecio filaginoides) thrive in disturbed sites. It is also possible in these sites to find annual plants which are too small to provide food for the large herbivores.

Wet Meadows and Peat Bogs

These communities are found in sites where the soil is permanently humid, so the species in the drier surroundings cannot thrive. Well known plants predominate here, like rushes, but belonging principally to two plant families, the Juncáceas (Juncus spp.) and the Ciperáceas (Carex spp., Cyperus spp., Eleocharis spp., etc.). These are greatly diverse communities, both in their situation (from the floors of wide valleys to high mountain peaks) and in the rainfall conditions they withstand. Peat bogs are different from wet meadows in that they receive water without nutrients and have a highly acid substrate, so the organic material decomposes very slowly.

In addition, since water is permanently available (generally from mountain tops) in the peat bogs, their water level varies less throughout the year. The woody species living in these communities develop very little and many grow as creepers. The wet meadows in the steppe tend to be under pressure from cattle in dry periods, and so exotic plants can become established there, such as clover (Trifolium repens) and dandelion (Taraxacum officinale).

High Andean Steppe

This is the type of vegetation that lives at the highest altitudes in the Andes (up to around 2200 masl). It is composed of cushion form or creeping plants, and perennial plants of low height. Although precipitation is higher here than at lower altitudes, the soil, extreme exposure to the wind, radiation and low nocturnal temperatures all signify unfavourable conditions for plants for much of the year.

As a consequence, many high Andean plants complete their annual cycles in few weeks and tend to grow very slowly. Despite these conditions a great diversity of species inhabit these high peaks, and the predominant species vary from one mountain to another. The compact shrubs known as llaretas (Azorella spp., Bolax spp.) are characteristic of this habitat, as are the chauras enanas (Gaultheria spp.), the columnar violets (Viola spp.) and various species of Senecium.

Javier Puntieri, INIBIOMA, CONICET, Universidad Nacional de Río Negro.


Birding Patagonia • Birdwatcing in Bariloche, Patagonia, Argentina and Chile.
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