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Habitat Changes on the Falkland Islands

51.7S 59.4W

January 31st, 2013 Category: Snapshots

Argentina – January 29th, 2013

The Falkland Islands (Islas Malvinas) are located in the South Atlantic Ocean on a projection of the Patagonian Shelf about 310 miles (500 kilometres) east of the Patagonian coastline and about 280 miles (450 kilometres) north-east of the southerly tip of Tierra del Fuego, Argentina. The Falklands, which have a total land area of 4,700 square miles (12,173 square kilometres) and a coastline estimated at 2,200 miles (3,500 km)[92] comprise two main islands, West Falkland and East Falkland and about 776 smaller islands. The two principal islands are 140 miles (220 km) from east to west and 87 miles (140 km) from north to south. They are heavily indented by sounds and fjords and have many natural harbours. The two main islands are separated by the Falkland Sound.

There is little long-term data on habitat changes, so the extent of human impact to the islands is unclear. Vegetation such as tussac grass, fachine, and native box have been heavily impacted by introduced grazing animals. Virtually the entire area of the islands is used as pasture for sheep. Rats and Grey foxes have been introduced and are having a detrimental impact on birds that nest on the shores, as are feral cats. Many breeding birds similarly only live on offshore islands, where introduced animals such as cats and rats are not found. There is also an introduced reindeer population, which was brought to the islands in 2001 for commercial purposes. Twenty two introduced plant species are thought to provide a significant threat to local flora.

Salinity and Seagrass of Shark Bay, Australia

25.7S 113.6E

December 20th, 2012 Category: Snapshots

Australia – December 19th, 2012

The waters of Shark Bay, Australia, appear greenish in color due to phytoplankton growth and shallower depths. In the bay’s hot, dry climate, evaporation greatly exceeds the annual precipitation rate. Thus, the seawater in the shallow bays becomes very salt-concentrated, or ‘hypersaline’. Seagrasses also restrict the tidal flow of waters through the bay area, preventing the ocean tides from diluting the sea water. The water of the bay is 1.5 to 2 times more salty than the surrounding ocean waters.

Shark Bay has the largest known area of seagrass, with seagrass meadows covering over 4,800 km² of the bay. The seagrasses are a vital part of the complex environment of the bay. Over thousands of years, sediment and shell fragments have accumulated in the seagrasses to form vast expanses of seagrass beds. This has raised the sea floor, making the bay shallower.

Agriculture Across California’s Great Central Valley, USA

38.7N 121.5W

June 12th, 2012 Category: Snapshots

USA - June 11th, 2012

California’s Central Valley is a large, flat valley that dominates the central portion of California. The valley stretches approximately 450 miles (720 km) from northwest to southeast inland and parallel to the Pacific Ocean coast.

The ‘Central Valley Grassland’ is the Nearctic temperate and subtropical grasslands, savannas, and shrublands ecoregion which was once a diverse grassland containing areas of desert grassland (at the southern end), prairie, savanna, riverside woodland, marsh, several types of seasonal vernal pool and large lakes.

However much of the Central Valley environment has been removed or altered by human activity including the introduction of exotic plants, especially grasses. It is home to California’s most productive agricultural areas. The wetlands have been the target of rescue operations to restore areas nearly destroyed by agriculture

Desert Agriculture in Saudi Arabia

29.9N 38.3E

June 4th, 2012 Category: Snapshots

Saudi Arabia - June 1st, 2012

A great number of circular green and brown fields contrast with the surrounding orange and tan desert sands of arid Saudi Arabia. This agricultural technique is known as Center Pivot Irrigation – water from deep underground is pumped to the surface and distributed via large center pivot irrigation feeds.

These circular fields range from a few hundred meters in diameter to as much as 3 km (2 miles) across. Although the fields may appear to be dotted randomly across the landscape, they actually are planned by engineers who follow ancient river channels now buried by the desert sand.

Environmental Threats to Lesser Sunda Islands

8.6S 121.0E

May 22nd, 2012 Category: Snapshots

Indonesia - May 20th, 2012

This image shows several of the Lesser Sunda Islands, a group of islands in the southern Maritime Southeast Asia, north of Australia. The three largest islands visible here are Sumba, Flores and Timor (lower half of image, from left to right). The islands are part of a volcanic arc, the Sunda Arc, formed by subduction along the Java Trench in the Java Sea.

Although most of the vegetation on these islands is dry forest there are patches of rainforest on these islands too, especially in lowland areas and along riverbanks. However, the ecosystem is threatened: more than half of the original vegetation of the islands has been cleared for planting of rice and other crops, for settlement and by consequent forest fires.

While many ecological problems affect both small islands and large landmasses, small islands suffer their particular problems and are highly exposed to external forces. Development pressures on small islands are increasing, although their effects are not always anticipated. Although Indonesia is richly endowed with natural resources, the resources of the small islands of Nusa Tenggara are limited and specialised; furthermore human resources in particular are limited.