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28-1021: Key traits of urban wilderness that differentiate it from other urban green spaces: Various urban wilderness areas have been established throughout the world. Examples include the Knoxville Urban Wilderness in Knoxville, TN, Purgatory Creek Natural Area in San Marcos, TX, the Danube-Auen National Park in Vienna and Lower Austria, the Turkey Mountain Urban Wilderness Area in Tulsa, and the Milwaukee River Greenway in Milwaukee, WI. The nineteenth and twentieth centuries saw

56-418: A courtship display , and females lay around 200 eggs individually onto leaves of aquatic plants. Larvae develop two to four months in the water before reaching metamorphosis . For the remainder of the year, the newts live in shady land habitats, usually forests. Although not yet considered threatened, Danube crested newt populations have declined significantly, the reason being mainly habitat loss . The species

84-485: A large area of lowland forests, meadows, wetlands, and other riparian habitat along the Danube just downstream of Vienna. The Park was designated an IUCN category II national park and spans the areas of Vienna ( Lobau ), Groß-Enzersdorf , Orth an der Donau , Eckartsau , Engelhartstetten , Hainburg , Bad Deutsch-Altenburg , Petronell-Carnuntum , Regelsbrunn , Haslau-Maria Ellend , Fischamend and Schwechat . Until

112-720: A nearly unbroken chain of hydroelectric power plants and associated dams on the Austrian section of the Danube River. In 1984, the planned construction of the Hainburg hydroelectric power plant, just downstream from Vienna, threatened to destry one of two remaining free-flowing sections of the Danube in Austria and its riparian forests (the other remaining free-flowing section in Austria is upstream, near Wachau ). An outcry by environmental and nature protection groups caused nationwide protests against

140-541: A pause for reflection. In January 1985 the Austrian Supreme Court forbad further deforestation. In March 1985, the so-called Konrad Lorenz-Volksbegehren (petition), signed by 353,906 people, demanded the prohibition of large power plants such as Hainburg and the establishment of a national park in the area of Hainburg. On 1 July 1986, the Administrative Court released a decision cancelling the water rights of

168-597: A power plant in the area would not be compatible with national park status for the region. On October 27, 1996, a State Treaty between the Republic of Austria and the federal states of Vienna and Lower Austria was signed. With that treaty, Donau-Auen National Park was officially opened. In the National Park area there are more than 700 species of higher plants, more than 30 mammals, 100 species of breeding birds, 8 reptiles, 13 amphibian species, and around 50 species of fish. Among

196-410: A strong impact on the natural flow dynamics, by stabilizing riverbanks, by reducing erosion, and by creating areas of reducing or increased flow rates, and thus affecting in which areas sediments are deposited or removed. Large tree trunks and accumulations of smaller flotsam cause the water to stagnate and the speed of the current to drop, leading to increased sedimentation. To counteract the effects of

224-524: Is a bluish-white stripe along the tail. Females can sometimes have a yellow stripe along the back, similar to the Italian crested newt ( T. carnifex ). The Danube crested newt is found in three allopatric areas of distribution from central to eastern Europe: In addition to the northern crested newt to the north, the Danube crested newt's range borders that of the Italian crested newt ( T. carnifex ) in

252-500: Is available. During land phase, the newts live in deciduous forests or groves, bushlands, or meadows. Danube crested newts have the longest aquatic phase in the genus Triturus . Adults move to their breeding sites in February or March and usually stay there for six months; occasionally, they may even stay longer or return to the water in autumn. Males court females with a display of ritualised body movements. When they have gained

280-720: Is one of the largest remaining floodplains of the Danube in Middle Europe . The German word Aue (variant Au ) means " river island , wetland , floodplain, riparian woodland ", i.e. a cultivated landscape in a riparian zone . The words Aue and Au occur in a large number of German place names—including Donau , the German word for the Danube River—and refer to forests, meadows, and wetlands in river and stream lowlands and floodplains. The Danube-Auen National Park protects

308-422: Is orange to red (in other crested newts, it is usually yellow or orange–yellow), with small or medium-sized black blotches that have sharp edges. Like all crested newts, T. dobrogicus males develop a crest on their back and tail during breeding phase, which can be quite high and jagged, usually starts between the eyes and nostrils, and is interrupted at the tail base. Another feature of males at breeding season

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336-503: Is protected by law in the European Union. The Danube crested newt was described as a variety of the northern crested newt ( Triturus cristatus ) by C. Kiritzescu in 1903. Later, it was considered a subspecies until genetic analysis supported its recognition as a separate species in the crested newt species complex . The northern crested newt is its sister species , according to phylogenomic studies. Separated populations from

364-519: The Danube Delta and the Pannonian Basin (see section Distribution and habitats ) were described as two subspecies, T. dobrogicus dobrogicus and T. dobrogicus macrosoma , in 2000. Later genetic study, however, did not support the distinction of these two forms. Measuring 13 to 15 centimetres (5.1 to 5.9 in) long in total, sometimes up to 18 centimetres (7.1 in) in females,

392-1034: The urbanization of cities. Jacob Riis and other reformers fought for parks in urban areas. While many societies had traditions of intense urban plantings, such as the rooftops of pre-conquistador Mexico City , these traditions did not reemerge on a larger scale in the industrialized world until the creation of naturalistic urban parks, such as the ones by Calvert Vaux and Frederick Law Olmsted . More recently, groups such as squatters and Reclaim The Streets have performed guerrilla plantings, worked in and on abandoned buildings, and torn holes in highway asphalt to fill with soil and flowers. These actions have been effective in creating new planted zones in economically stagnant areas like urban Eastern Germany , where abandoned buildings have been reverted to forest-like conditions. Danube-Auen National Park Donau-Auen National Park ( German : Nationalpark Donau-Auen ) covers 93 square kilometres in Vienna and Lower Austria and

420-427: The 19th century the Danube was an untamed river. In the 19th century, extensive engineering began to alter the natural balance of the river landscape dramatically. Many side-channels were dammed so that they now carry water from the Danube only at flood stages. Ever more intrusive engineering interventions were accompanied by decades of heavy forestry use in many parts of lowland forests. In the 1950s, development began of

448-532: The Danube crested newt has declined significantly, and the International Union for Conservation of Nature has assessed its conservation status as " least concern ". The main threat is habitat destruction by humans, especially through drainage, damming, or pollution. Hybridisation with other crested newt species and a loss of breeding ponds because of decreasing spring rain in the southern range (possibly due to global warming ) are also seen as threats. Like

476-488: The Danube crested newt is the smallest crested newt species. It has a more slender, elongate body than the other species, well adapted to swimming, with a narrow head and relatively short limbs. This body shape has evolved through an increase in the number of rib -bearing vertebrae : there are 16–17 of them in T. dobrogicus , the highest number among the crested newts. The Danube crested newt's back and sides are dark brown with black spots and white stippling. The belly

504-432: The Danube was separated from its side channels by the flood control measures that were constructed around the year 1900. The outcome was a higher current velocity in the main channel, with a resulting deepening of the river bed, while in the side channels—which no longer had current flowing through them—sand and loam deposits were no longer removed by the current. In a natural riparian ecosystem woody plants and deadwood have

532-463: The basin of the Danube river and some of its tributaries and in the Dnieper delta. It has a smaller and more slender body than the other crested newts in genus Triturus but like these, males develop a conspicuous jagged seam on back and tail during breeding season. For half of the year or longer, adults live in slow-flowing river margins, lakes, or ponds, where reproduction takes place. Males perform

560-428: The complete flood works were removed across the river from Hainburg, so that the river once again could spread into the floodplain areas. In a similar project near Witzelsdorf , about one kilometer of the levees were removed. After the completion of the pilot projects in Hainburg and Witzelsdorf, future plans for this river engineering project are for removal of 50% of the levees and flood control works between Vienna and

588-455: The eastern border of Austria. Aside from a revitalization of the Au ( riparian zone ), the project promises to mediate the effects of floods on the river and to stabilize the riverbed to the benefit of both river ecology and navigation. Danube crested newt The Danube crested newt or Danube newt ( Triturus dobrogicus ) is a species of newt found in central and eastern Europe, along

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616-458: The female's interest, they guide it over a spermatophore they deposit on the ground, which the female then takes up with her cloaca . The eggs are fertilised internally. As in other crested newts, a female lays around 200 eggs per season, which are folded individually into leaves of aquatic plants. Eggs and larvae are smaller than in the other crested newt species, and they take longer (two to four months) until they reach metamorphosis and leave

644-528: The flood control measures, beginning in 2002 individual side channels were tied in with the main channel again—at least at high water times—via Gewässervernetzungen ("water crossings"), which lower or remove the levees protecting those channels. In a 2006 pilot project created with the support of the LIFE+ Program of the European Union and the Austrian riverways agency via donau , about three kilometers of

672-483: The most characteristic inhabitants of the wetlands of the National Park are the Danube crested newt , European pond turtle , European mudminnow , white-tailed eagle , Eurasian kingfisher , and Eurasian beaver . With the variety of insects living on both land and water, and other invertebrates, the total number of species in Donau-Auen National Park is estimated to be at least 5,000. The main channel of

700-415: The planned power plant. Extensive scientific studies were then made of the area, with surprising discoveries. More species of fish were observed than was known at the time the planning of the power plant. The most important result of these studies was that the Danube lowlands area (Donau-Auen) in and east of Vienna was determined to be worthy of becoming a national park. It was also determined that creating

728-513: The project. The operator of the power plant project disregarded the protests and began work to clear the area. Protests stepped up, eventually leading to the occupation of the Hainburg wetlands by thousands of people from all ages and professions (the so-called "Hainburg Movement"). After police tried several times to clear protestors from the area, in December 1984 the Federal Government declared

756-468: The water. Both in water and on land, the newts are largely nocturnal. In their aquatic habitats, they hide under vegetation, and on land, they use structures such as logs, rocks, or small animal burrows for cover. They feed mainly on different invertebrates , but in the water may also prey on tadpoles and smaller newts. Predators include herons and other birds, snakes such as the grass snake , and various carnivorous mammals. The population of

784-517: The west, and that of the Macedonian ( T. macedonicus ) and Balkan ( T. ivanbureschi ) crested newts in the south. Compared to the other crested newt species, the Danube crested newt is more adapted to life along a river system and frequently occurs in flowing water and together with fish. Typical breeding sites are slow-flowing river margins, oxbow lakes , flooded marshland , larger ponds, or ditches, provided abundant underwater vegetation

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