Flora and Vegetation of New Guinea
The flora and vegetation of New Guinea , the second largest island in the world, located in the South Pacific and up to almost 5,000 meters high in its center, is one of the most important botanical hot spots in the world. Around 20,000 to 25,000 species, more than half of which only occur here, make New Guinea one of the most species-rich and peculiar floristic regions on earth.
Regardless of its abundance, the flora and vegetation of New Guinea has so far only been insufficiently researched, and although it has been preserved relatively well up to the present, severe interventions in nature for the benefit of economic interests have begun in recent decades, especially in the much less explored western part of the island .
geography
New Guinea is an island, including some offshore islands and archipelagos, around 786,000 km² (Germany: 357,100 km²) on the northeastern tip of the Australian continent at 5 ° 20'S, 141 ° 36'E. It is separated from Australia by the 150 km wide Torres Strait at its narrowest point .
The island, which is elongated from northwest to southeast, is traversed and divided over its entire length by around 200 km wide mountains (in the west as the Maoke Mountains , in the east as the Bismarck Mountains ), which reach heights of almost 5,000 m ( Puncak Jaya : 4,884 m, Puncak Trikora : 4,730 m, Ngga Pilimsit : 4,717 m, Puncak Mandala : 4,640 m, Mount Wilhelm : 4,509 m).
climate
In addition to local factors such as the altitude, especially in the alpine area, the island's temperatures are determined by the equatorial position of the island, but the wind and rainfall are also influenced by the monsoons .
In the lower altitudes it is continuously hot (on the coast the average monthly temperature is around 27 ° C all year round) and extremely humid without seasonal fluctuations. The average annual precipitation on the coast is around 2800 mm, but in the inland south of the mountain ranges (e.g. Daru Plain) it can rise to values between 5000 and 6000 mm. Due to the influence of the monsoons, there are times of lower rainfall (in the north mainly December to March, in the south mainly between May and October) or heavy rainfall, although these differ significantly from region to region. Noteworthy exceptions to the general abundance of precipitation on the island are zones of relative aridity with less than 2500 mm annual precipitation, mainly in the lowlands, where evergreen dry forests or savannas are found instead of tropical rainforests .
With increasing altitude, the temperatures decrease, but also remain stable all year round. In Kutubu at 885 m the mean annual temperature is 23.3 ° C, in Baliem and Goroka at 1660 and 1730 m 19 ° C and 20.2 ° C and in Wabag (1981 m) only 16.8 ° C .
In the highest elevations of the Puncak Jaya, the Ngga Pilimsit and the Puncak Mandala there are even glaciers , but these are falling drastically due to the melting of the glaciers due to climate change. Precipitation and temperatures here are stable all year round and are subject to only slight fluctuations, the temperatures are around 8 ° C at 3,600 m and around 3.5 ° C at 4,200 m, precipitation values for the Puncak Jaya resulted in estimated annual rainfall between 2,800 and 3,000 mm.
Floristry and biodiversity
New Guinea, regardless of its geographical affiliation to the Australian continent, is part of the Oceanic Floral Kingdom . Dominated by rainforests island has floristically the ten most biodiverse regions in the world, its flora comprises from 20 to 25,000 species of over 1500 species in 250 families. Particularly noticeable is the high proportion of species that are not found anywhere else in the world (so-called endemics ), around 55%.
The high number of species is favored by the island's wealth of different biotopes and habitats , which is due on the one hand to the geographical diversity of the island and on the other to its closed vegetation, around 75% of the area of New Guinea, which has been largely untouched by human intervention are covered with forests alone. In recent times, however, this unity is increasingly endangered , especially in West New Guinea, which is politically part of Indonesia, due to massive logging and the subsequent conversion into agricultural land.
Regardless of the diversity and current endangerment, New Guinea, with collection values of less than 50 (East) or 25 (West) collections per 100 km², is at the same time the botanically least developed tropical metropolitan area.
Flora story
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New Guinea is part of the Australian continent and forms the northernmost part of the Australian plate . With the breakup of the southern supercontinent Gondwana about 150 million years ago, Australia gradually separated from South America , Africa , India and Antarctica and rotated counterclockwise. The Gondwanian flora that predominated in New Guinea at that time was essentially adapted to warm-temperate conditions.
Around 80 million years ago, the continent gradually began to drift north towards the equator and later collided with the Eurasian plate . Due to the climatic changes during the continental drift , the flora of New Guinea was exposed to increasingly tropical conditions; the previous floral elements either died out, adapted to the new conditions or withdrew to locations that still met their requirements. From such island locations, a new expansion was favored, in particular by the unfolding of today's mountains from the Miocene around 25 million years ago to the formation of the high mountains at the end of the Pliocene around 2 million years ago, as the conditions were higher Locations partially correspond to moderate conditions. Up until the present day, the flora of the high mountains is dominated by descendants of Gondwanian floral elements, and the families and genera that occur here have their closest relatives in the temperate zones of South America.
At the same time, the new proximity to the Eurasian Plate enabled the immigration of previously non-indigenous species from Asia, which had already adapted to the now prevailing tropical conditions and which, due to the partial retreat of the temperate flora, conquered the habitats mainly in the lower elevations and dominates them to this day .
However, there was also immigration from Australia. The Gulf of Carpentaria, which separates the two land masses, to the west of the Torres Strait , which is only 12 meters deep and only reaches depths of up to 53 meters, as well as parts of the Arafura Sea to the west have repeatedly fallen completely or partially dry over the course of the earth's history, especially during the cold periods the last 3 million years, the last time up to around 10,000 years ago. This created regular land connections between New Guinea and northeast Australia, through which not only humans and animals but also plants migrated. Regardless of this, the proportion of plants with an origin in the Australian flora is comparatively low.
vegetation
Due to the geographical situation of the island, which builds up evenly from the coast to the high mountains, the vegetation of Papua New Guinea is mostly divided according to the altitude levels, the following illustration follows K. Paijmans et al. 1976. As a supplementary deviation from this model, however, there is also a horizontal differentiation in the lowlands into rainforest areas with high levels of precipitation and dry forest areas and savanna areas with less precipitation. Some types of vegetation that are not primarily climatic must be integrated into this model.
Beach coast ( Coastal beach ridges and flats )
In front of the actual coast there are seagrass meadows consisting of Thalassia , Enhalus , Halophila and Cymodocea species in shallow coastal waters . They represent the pasture grounds of the dugongs .
The coastal zone formed as a beach ( Coastal beach ridges and flats ) is the smallest of all vegetation zones with a share of only 0.5% of the total area of all biotopes and is divided into five types of vegetation.
The herbaceous vegetation beach ( Herbaceous beach vegetation ) adjacent to the sea and directly starts behind the flood zone. Dominate sedges , grasses and low herbaceous plants such as Ipomoea pes-caprae ( Ipomoea pes-caprae ) (after the formation "pes-caprae formation" means), Canavalia maritima and behind Ischaemum muticum Fimbristylis species, Cyperus peduncullatus and Cassytha filiformis . All species fortify the sand, are tolerant of the extreme salt, wind and temperature conditions and are widespread in the oceanic flora and the Australis .
In this area already take part in some bushes and low trees whose stocks can condense and then the type of vegetation beach bushes ( Beach Scrub form). Typical are lime-leaved marshmallow , Desmodium umbellatum and Flagellaria indica . This type of vegetation is predominant on some offshore coral islands, supplemented in particular by species of the genera fan flowers ( Scaevola ) and Messerschmidia as well as Allophylus cobbe and Pemphis acidula .
If there is no beach scrub the Herbaceous beach vegetation goes directly to beach Woodlands ( Beach Woodlands on) that after having prevailing Barringtonia asiatica as " Barringtonia formation is called". It also appears as a pioneering society when, e.g. B. because of eroded coasts or on rock or pumice soils , the herbaceous beach vegetation is missing. In addition to B. asiatica there are screw trees ( P. tectorius , P. dubius ), katappenbaum and Calophyllum inophyllum . The undergrowth can be closed in more open tree stands and is composed of ferns , ginger plants , grasses and herbaceous plants such as Crinum asiaticum . In the vicinity of mangroves there are also minor occurrences of Acrostichum aureum and Acanthus illicifolius .
Kasuarinenwald ( Casuarina forest ) is a pioneer company on beaches and estuaries. Dominated by the horsetail cassuarine , it is more of a temporary nature. With decreasing tree density, this type of vegetation dissolves through undergrowth and subsequent vegetation through broad-leaved trees and turns into beach woodlands or - in the south - mixed coastal forest ( Mixed littoral forest ), a widespread and quite species-rich vegetation type with palm trees , syzygium , myrobalans , erythrina , pterocarpus indicus , Sarcocephalus coadunate , Derris indica , the climbing fern Stenochlaena and - in the southwest - acacias . Planchonia papuana , Melaleuca cajuputi and scattered mangroves can be found in wet locations .
Salt and brackish water marshes ( saline and brackish swamps )
The most characteristic types of vegetation on the coast are the mangroves . With around 1.5% of the total area, they only take up a small part of the island, but comprise around 75% of the coastline. Mangroves can be found from the direct coast to inland and are highly dependent on the combination of factors such as soil, salinity or tides. Favorable habitats are estuaries with their protection against strong waves and high and even precipitation values. Here there are seven types of vegetation, which are always dominated by only one or a few mangrove species.
A dense pioneer vegetation in muddy coastal areas is the mangrove bushes ( Mangrove scrub ), dominated by Avicennia marina and Sonneratia caseolaris and, more rarely, Ceriops tagal . Dominated by other Sonneratia , it is also found on flat river banks and on small islands in the tidal area of river mouths.
This pioneering company often following or in sheltered locations itself as a pioneer vegetation is that of Rhizophora -dominated Lower mangrove forest ( low mangrove forest ). Young forests have a dense canopy that barely lets light through for undergrowth, and there are also no epiphytes and climbing plants. Only later did among other mangroves (see Bruguiera ) acrostichum ( Acrostichum ) and the climbing plant Derris trifoliata .
Older forests become full-grown mangrove forest ( Mature mangrove forest ). Trees can now reach heights of up to 30 meters, the canopy opens and allows light for a more pronounced undergrowth (in addition to mangrove seedlings and mangrove ferns, acanthus and occasional nipa palms ), epiphytes and climbers as well as hoya , Dischidia , Myrmecodia , orchids and ferns . With decreasing salinity, the number of species increases inland, trees such as Camptostemon schultzii , Heriteria littoralis and Intsia bijuga are typical . Shrubs and small trees ( Aegiceras corniculatum , Brownlowia argentata , Myristica hollrungii ) form, together with palms and screw trees, a multi-layered undergrowth, open zones are dominated by the latter in combination with sedges . Mature mangrove forests can merge directly into the vegetation zone of the lowland freshwater swamps, the transition zone can be up to half a kilometer long.
In addition to these frequent, closely interlinked types of vegetation, there are special forms:
Avicennia-Busch and Woodland ( Avicennia scrub and woodland ) settled around the mangrove vegetations around locations on muddy as sandy soils with high salt content with less and seasonal rainfall. It is dominated by A. marina in the company of Sesuvium portulacastrum , Lumnitzera racemosa , Ceriops tagal , Batis argillicola (in southwest New Guinea) and - in less flooded areas - by sedges. In the transition zones between Avicennia bush and woodland and dry grassland or eucalyptus savannas, Sporobolus grassland ( Sporobolus grassland ) occurs, a type of vegetation that is regularly flooded by freshwater.
Similar claims have the Excoecaria-Busch and Woodland ( Excoecaria scrub and woodland , which is, however, specializes in marshland). In the undergrowth of the dominant Excoecaria agallocha there are linden-leaved marshmallow and Pluchea indica as well as mangrove ferns , which are displaced by grasses and sedges as the proportion of freshwater increases, here acacias and myrtle heaths ( Melaleuca ) mix between the Excoecaria .
Nipa palm woodland ( Nipa palm woodland ) forms almost monocultures, only rarely are some mangrove ferns or hook lilies . It is restricted to low-lying areas in estuaries and their tributaries that are flooded daily by brackish water.
Lowland freshwater swamps
Lowland freshwater swamps are areas that range from the vegetation of open water bodies to herbaceous plant communities, grasslands, savannas and woodlands to swamp forests.
Aquatic vegetation in deep waters is dominated by plant communities of freely floating species such as Lemna , Azolla imbricata , water hoses and Pista stratiotes , which either appear mixed or in large colonies of individual species. As the depth decreases, rooting plants such as horn leaf , water lilies , nymphoides and Nelumbo nucifera can be found from around three meters of water , which reach up to the herbaceous swamp vegetation. In shallow waters they can also form extensive populations across entire lakes or lagoons .
The Herbaceous marsh vegetation ( Herbaceous swamp vegetation ) closes to open waters to, accordingly, the swampy conditions are permanent and the water relatively deep. Sedges (often Scleria , Thoracostachyum sumatranum ), ferns ( Cyclosorus ) and herbaceous plants ( Hanguana malayana ) grow on floating mats made of peat and humus between the often humic acidic water . In the center of the vegetation the biodiversity is decreasing, here, besides low sedges, mostly only gleichenia and bear moss can be found , before grasses and occasional screw trees, sago palms and other shrubs and low trees appear in the run-off zone .
Leersia grass marshes ( Leersia grass swamp ) are dominated by medium-high marsh grasses such as Leersia hexandra , rice , Panicum , amplexicaulis Hymenachne , Echinochloa stagnina that also wet on permanently but temporarily grow up to 3 meters high flooded sites, a type of vegetation, which Occasionally also found at special locations on lakes and lagoons. The sward in turn serves as the basis for knotweed , hayweeds or water spinach .
Saccharum-Phragmites grass swamp ( Saccharum-Phragmites grass swamp ) are significantly less wet and can sometimes dry out. Here higher grasses such as Saccharum robustum (dominant in moving water with rapid fluctuations in the water level) or Phragmites karka (in stagnant water with fluctuations in level up to several months of drought) predominate. In addition to the grasses mentioned, there are scattered small trees or bushes ( Glochidion , Nauclea coadunata , Mitragyna speciosa , Livistona ,), but the conditions for them are borderline, many individuals die again quickly.
Pseudoraphis grass swamp ( Pseudoraphis grass swamp ) is formed almost entirely by Pseudoraphis spinescens , a creeping, matting swamp grass. Except for a seasonal dry phase, the sward is always slightly flooded, in the dry season it stands up and is grazed intensively by deer and wallabies .
As a transition zone between the Herbaceous marsh vegetation and marsh Woodlands (see below) can be found in continuously and uniformly wet areas Mixed swamp Savannah ( Mixed swamp savanna ). The undergrowth is largely identical to that of the herbaceous swamp vegetation, but is accompanied by individual trees of the genera Nauclea , Campnosperma , Myrtle Heath and Syzygium .
The myrtle heather swamp savannah ( Melaleuca swamp savanna ) can only be found in the region around the Fly River and the Strickland River and occasionally in the south and south-west on beach plains. While the undergrowth consists almost exclusively of reeds with isolated lower marsh grasses and sedges, myrtle heaths (especially Melaleuca cajuputi and Melaleuca leucadendron ) dominate the open tree layer, occasionally accompanied by Nauclea coadunata , Livistona , screw trees and sago palms . The locations are wet and dry depending on the season, and fires regularly occur in the dry season.
proof
- Handbooks to the Flora of Papua New Guinea , Papua New Guinea National Herbarium, 1978, 1981, 1995, ( Online )
- Paijmans, K., MMJ van Balgooy, JM Powell: New Guinea Vegetation , 1976, CSIRO, Canberra, ( Online )
- Muller, Kal: Keregaman Hayati Tanah Papua [The Biodiversity of Papua] , Manokwari Universitas Negeri Papua (kerjasama dgn Dinas Pendidikan dan Pengajaran Provinsi Papua), ISBN 979-97700-5-X , ( Online )
- Hope, Geoff S, et al. (Editors): The Equatorial Glaciers of New Guinea (Results of the 1971-1973 Australian Universities' Expeditions to Irian Jaya: survey, glaciology, meteorology, biology and palaeoenvironments) , 1976, ( Online )
- Selvaradjou, SK., L. Montanarella, O. Spaargaren, D. Dent: European Digital Archive of Soil Maps (EuDASM) - Soil Maps of Asia DVD-ROM version. EUR 21823 EN. Office of the Official Publications of the European Communities, Luxembourg, 2005, Online
Individual evidence
The information in this article is taken from the literature given under references; the following literature is also cited:
- ^ Ian Allison, James A. Peterson (2000): Glaciers of Irian Jaya, Indonesia and New Zealand , US Geological Survey, US Department of the Interior, online
- ↑ Arithmetic mean according to information from Brookfield, Hart: New Guinea. Rainfall Distribution and Climatic Diagrams. , 1966, Commonwealth Scientific and Industrial Research Organization, Australia, Canberra, in: Selvaradjou, SK., L. Montanarella, O. Spaargaren, D. Dent: European Digital Archive of Soil Maps (EuDASM) - Soil Maps of Asia , DVD- ROM version, EUR 21823 EN, Office of the Official Publications of the European Communities, Luxembourg, 2005, Online JPG ( Memento of the original from September 5, 2015 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Brookfield, Hart: New Guinea. Rainfall Distribution and Climatic Diagrams. , 1966, Commonwealth Scientific and Industrial Research Organization, Australia, Canberra, in: Selvaradjou, SK., L. Montanarella, O. Spaargaren, D. Dent: European Digital Archive of Soil Maps (EuDASM) - Soil Maps of Asia , DVD- ROM version, EUR 21823 EN, Office of the Official Publications of the European Communities, Luxembourg, 2005, Online JPG ( Memento of the original from September 5, 2015 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Topographic service of The Netherlands: Rainfall Distribution and Climatic Diagrams New Guinea , undated, in: Selvaradjou, SK., L. Montanarella, O. Spaargaren, D. Dent: European Digital Archive of Soil Maps (EuDASM) - Soil Maps of Asia , DVD-ROM version, EUR 21823 EN, Office of the Official Publications of the European Communities, Luxembourg, 2005, Online JPG ( Memento of the original from September 5, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ Ian Allison, James A. Peterson (2000): Glaciers of Irian Jaya, Indonesia and New Zealand , US Geological Survey, US Department of the Interior, Online
- ↑ Hope, Geoff S, et al. (Editors): The Equatorial Glaciers of New Guinea (Results of the 1971-1973 Australian Universities' Expeditions to Irian Jaya: survey, glaciology, meteorology, biology and palaeoenvironments) , 1976, pp . 62-63
- ↑ Hope, Geoff S, et al. (Editors): The Equatorial Glaciers of New Guinea (Results of the 1971-1973 Australian Universities' Expeditions to Irian Jaya: survey, glaciology, meteorology, biology and palaeoenvironments) , 1976, pp . 69-71
- ↑ Barthlott et al .: Global Biodiversity - Species Numbers of Vascular Plants , Tafel, between pp. 1003 and 1004, Strasburger, 35th ed.
- ↑ MMJ van Balgooy: Phytogeography in: Paijmans, K. et al., 1976, p.5. The numbers of higher taxa given there are based on the Melchior system of the systematics of plants according to Engler , which is largely out of use today , and based on more recent systems, these numbers would in some cases be significantly higher.
- ↑ a b Kal Muller: Keregaman Hayati Tanah Papua [The Biodiversity of Papua]
- ^ Ghillean T. Prance, Henk Beentje, John Dransfield, Robert Johns: The Tropical Flora Remains Undercollected , in: Annals of the Missouri Botanical Garden, Vol. 87, No. 1, 2000, p. 70
- ↑ K. Paijmans: Part II: Vegetation In: K. Paijmans, MMJ van Balgooy, JM Powell: New Guinea Vegetation , 1976, CSIRO, Canberra, pp. 23-105
- ↑ K. Paijmans: Vegetation in: Paijmans, K. et al., 1976, p.24. The values given there refer only to Papua New Guinea alone, values for the entire island are not available.
- ↑ The term Woodlands cannot be translated correctly and is therefore used here in the original. As Woodlands is called in English tree stands, the more open and relaxed but are not as scattered as forests such as savannas .
