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Okavango Delta

Okavango Delta

This delta in north-west Botswana comprises permanent marshlands and seasonally flooded plains. It is one of the very few major interior delta systems that do not flow into a sea or ocean, with a wetland system that is almost intact. One of the unique characteristics of the site is that the annual flooding from the River Okavango occurs during the dry season, with the result that the native plants and animals have synchronized their biological cycles with these seasonal rains and floods. It is an exceptional example of the interaction between climatic, hydrological and biological processes. The Okavango Delta is home to some of the world’s most endangered species of large mammal, such as the cheetah, white rhinoceros, black rhinoceros, African wild dog and lion.

Delta de l’Okavango

Cette plaine située au nord-ouest du Botswana est composée de marécages permanents et de prairies saisonnièrement inondées. Il s’agit d’un des très rares grands systèmes de deltas intérieurs n’ayant pas de débouché dans la mer et d’un système de zones humides quasi intact. Une des caractéristiques uniques de ce site est que les crues annuelles se produisent en saison sèche, de sorte que les plantes et les animaux ont synchronisé leur rythme biologique avec les crues et les pluies annuelles. C’est un exemple exceptionnel de l’interaction des processus climatiques, hydrologiques et biologiques. Le delta de l’Okavango entretient des populations de certains des grands mammifères les plus en danger du monde tels que le guépard, le rhinocéros blanc et le rhinocéros noir, le lycaon et le lion.

Дельта Окаванго

Объект, расположенный на северо-западе Ботсваны, представляет собой болотистую низменность, состоящую из заливных лугов, пересечённых множеством рукавов и протоков. Дельта Окаванго – одно из немногих крупных дельта-подобных образований, не имеющих выхода к морю. Она также является примером почти нетронутой водно-болотистой системы. Одна из уникальных особенностей данного объекта состоит в том, что ежегодные наводнения происходят здесь во время сухого периода, так что растения и животные адаптировали свой биологический ритм к ежегодным наводнениям вне сезона дождей. Дельта Окаванго – это яркий пример взаимодействия климатических, гидрологических и биологических процессов. Она поддерживает популяцию ряда крупных млекопитающих, находящихся под наибольшей угрозой исчезновения, среди них гепард, белый и черный носорог, гиеновидная собака и лев.

source: UNESCO/ERI

Delta del Okavango

Situado al noroeste del país, este sitio está formado por una planicie de pantanos permanentes y de praderas inundables estacionalmente. Se trata de un complejo de zonas húmedas prácticamente intacto y de uno de los pocos sistemas de deltas interiores del mundo que carece de desembocadura al mar. Una de las características excepcionales del sitio estriba en que las crecidas anuales tienen lugar en la estación seca, lo cual hace que sus especies vegetales y animales hayan sincronizado su ritmo biológico con las inundaciones y lluvias anuales. El delta del Okavango constituye además un ejemplo, único en su género, de interacción de procesos climáticos, hidrológicos y biológicos, y alberga en su territorio poblaciones de algunos de los grandes mamíferos que mayor peligro de extinción corren actualmente, a saber: rinocerontes blancos y negros, licaones, leopardos y leones.

source: UNESCO/ERI

Okavango Delta

De Okavango delta in het noordwesten van Botswana bestaat uit permanente moerassen en seizoen-overstromende vlaktes. Het is een van de weinige grote inlandse delta’s die niet uitmonden in een zee of oceaan, met een bijna intact wetlandsysteem. Een van de unieke kenmerken van dit gebied is de jaarlijkse overstroming van de Okavango rivier tijdens het droge seizoen. De inheemse planten en dieren hebben hun biologische cyclus gesynchroniseerd met deze seizoensgebonden regenval en overstromingen. De delta is hierdoor een bijzonder voorbeeld van interactie tussen klimatologische, hydrologische en biologische processen. Het is de thuisbasis van enkele van 's werelds meest bedreigde grote zoogdieren, zoals de cheetah, witte neushoorn, zwarte neushoorn, de Afrikaanse wilde hond en de leeuw.

Source: unesco.nl

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Okavango Delta © Department of Wildlife and National Parks
Outstanding Universal Value

Brief synthesis 

The Okavango Delta is a large low gradient alluvial fan or ‘Inland Delta’ located in north-western Botswana. The area includes permanent swamps which cover approximately 600,000 ha along with up to 1.2m ha of seasonally flooded grassland. The inscribed World Heritage property encompasses an area of 2,023,590 ha with a buffer zone of 2,286,630 ha. The Okavango Delta is one of a very few large inland delta systems without an outlet to the sea, known as an endorheic delta, its waters drain instead into the desert sands of the Kalahari Basin. It is Africa’s third largest alluvial fan and the continent’s largest endorheic delta. Furthermore it is in a near pristine state being a largely untransformed wetland system. The biota has uniquely adapted their growth and reproductive behaviour, particularly the flooded grassland biota, to be timed with the arrival of floodwater in the dry, winter season of Botswana.

The geology of the area, a part of the African Rift Valley System, has resulted in the ‘capture’ of the Okavango River that has formed the Delta and its extensive waterways, swamps, flooded grasslands and floodplains. The Okavango River, at 1,500kms, is the third largest in southern Africa. The Delta’s dynamic geomorphological history has a major effect on the hydrology, determining water flow direction, inundation and dehydration of large areas within the Delta system. The site is an outstanding example of the interplay between climatic, geomorphological, hydrological, and biological processes that drive and shape the system and of the manner in which the Okavango Delta’s plants and animals have adapted their lifecycles to the annual cycle of rains and flooding. Subsurface precipitation of calcite and amorphous silica is an important process in creating islands and habitat gradients that support diverse terrestrial and aquatic biota within a wide range of ecological niches.  

Criterion (vii): Permanent crystal clear waters and dissolved nutrients transform the otherwise dry Kalahari Desert habitat into a scenic landscape of exceptional and rare beauty, and sustain an ecosystem of remarkable habitat and species diversity, thereby maintaining its ecological resilience and amazing natural phenomena. The annual flood-tide, which pulses through the wetland system every year, revitalizes ecosystems and is a critical life-force during the peak of the Botswana’s dry season (June/July). The Okavango Delta World Heritage property displays an extraordinary juxtaposition of a vibrant wetland in an arid landscape and the miraculous transformation of huge sandy, dry and brown depressions by winter season floods triggers spectacular wildlife displays: large herds of African Elephant, Buffalo, Red Lechwe, Zebra and other large animals splashing, playing, and drinking the clear waters of the Okavango having survived the dry autumn season or their weeks’ long migration across the Kalahari Desert.

Criterion (ix): The Okavango Delta World Heritage property is an outstanding example of the complexity, inter-dependence and interplay of climatic, geo-morphological, hydrological, and biological processes. The continuous transformation of geomorphic features such as islands, channels, river banks, flood plains, oxbow lakes and lagoons in turn influences the abiotic and biotic dynamics of the Delta including dryland grasslands and woodland habitats. The property exemplifies a number of ecological processes related to flood inundation, channelization, nutrient cycling and the associated biological processes of breeding, growth, migration, colonization and plant succession. These ecological processes provide a scientific benchmark to compare similar and human-impacted systems elsewhere and give insight into the long-term evolution of such wetland systems.

Criterion (x): The Okavango Delta World Heritage property sustains robust populations of some of the world’s most endangered large mammals such as Cheetah, white and black Rhinoceros, Wild Dog and Lion, all adapted to living in this wetland system. The Delta’s habitats are species rich with 1061 plants (belonging to 134 families and 530 genera), 89 fish, 64 reptiles, 482 species of birds and 130 species of mammals. The natural habitats of the nominated area are diverse and include permanent and seasonal rivers and lagoons, permanent swamps, seasonal and occasionally flooded grasslands, riparian forest, dry deciduous woodlands, and island communities. Each of these habitats has a distinct species composition comprising all the major classes of aquatic organisms, reptiles, birds and mammals. The Okavango Delta is further recognized as an Important Bird Area, harbouring 24 species of globally threatened birds, including among others, six species of Vulture, the Southern Ground-Hornbill, Wattled Crane and Slaty Egret. Thirty-three species of water birds occur in the Okavango Delta in numbers that exceed 0.5% of their global or regional population. Finally Botswana supports the world’s largest population of elephants, numbering around 130,000: the Okavango Delta is the core area for this species’ survival.

Integrity

The property covers most of the Delta, encompassing a vast area of over 2 millions ha of substantially undisturbed wetlands and seasonally flooded grasslands. It is of sufficient size to represent all of the delta’s main biophysical processes and features and support its communities of plant and animal species. Because of its vast size and difficult access the delta has never been subject to significant development and it remains in an almost pristine condition. Tourism to the inner Delta is limited to small, temporary tented camps with access by air. Facilities are carefully monitored for compliance with environmental standards and have minimal ecological impact. Most importantly, the source of the Okavango Delta’s waters in Angola and Namibia remain unaffected by any upstream dams or significant water abstraction and the three riparian states have established a protocol under the Permanent Okavango River Basin Water Commission (OKACOM) for the sustainable management of the entire river system. OKACOM has formally supported the inscription of the Okavango Delta on the World Heritage List. It is imperative that upstream environmental water flows remain unimpeded and that over abstraction of water, the building of dams and the development of agricultural irrigation systems do not impact on the sensitive hydrology of the property.

Concerns have been noted regarding fluctuating populations of large animals. Elephant numbers have been increasing whilst other species are reported as exhibiting significant declines. Data is variable, subject to different survey techniques and uncoordinated surveys undertaken by different institutions all contribute to an unclear picture of the Okavango Delta’s wildlife. Authorities have initiated efforts to establish a comprehensive and integrated wildlife monitoring system that can accurately track population size and trends for the entire property, however ongoing work is needed to realise this. Causes of decline are attributed to seasonal variability, poaching (for example of giraffe for meat) and veterinary cordon fencing used to manage animal sanitation and control the spread of disease between wildlife and domestic stock.

Mining activities including prospecting will not be permitted within the property. Furthermore, potential impacts from mining including concessions in the buffer zone and outside the buffer zone need to be carefully monitored and managed to avoid direct and indirect impacts to the property, including water pollution. The State Party should also work with State Parties upstream from the Delta to monitor any potential impacts, including from potential diamond mining in Angola, which could impact water flow or water quality in the Delta.

Protection and management requirements

The Okavango Delta comprises a mosaic of protected lands. About 40% of the property is protected within the Moremi Game Reserve, and the remainder is composed of 18 Wildlife Management Areas and a Controlled Hunting Areas managed by community trusts or private tourism concession-holders. Legal protection is afforded through Botswana’s Wildlife Conservation and National Parks Act, 1992 and an associated Wildlife Conservation Policy. The Tribal Land Act of 1968 also applies to the property and the whole of the nominated area (and the buffer zone) is communally-owned Tribal Land under the control of the Tawana Land Board.

As noted above the underlying causes of wildlife population declines are not clear, but an imposed hunting ban will further strengthen conservation measures in the property. The State Party is encouraged to develop a coordinated and systematic wildlife monitoring programme to establish population baselines for key species and to track trends. Veterinary cordon fences are known to cause significant disruption to wildlife at individual, population and species levels. Most of the property’s core and buffer zones are free of veterinary cordon fencing and the location of site’s boundaries was guided by these considerations. However, the Southern Buffalo Fence defines the southern boundary of the World Heritage property and whilst damage has compromised its effectiveness in disease control, it acts as a locally known demarcation to stop cattle grazing within the property. The Northern Buffalo Fence, also within the alignment of the property buffer zone, is known to disrupt connectivity in particular for the region’s Roan and Sable Antelope populations. Veterinary fencing is recognised as a sensitive, multi-dimensional issue. The State Party is encouraged to continue efforts to rationalize fencing, removing it when its effectiveness for disease control has become questionable or where more holistic approaches to animal sanitation and disease control are possible.

Ongoing vigilance is critical to ensure mining developments do not adversely impact the property. Past mining prospecting licences have been extinguished, and will not be renewed or extended. No extractive activity is undertaken in the property, and no new licenses will be issued within the property. The State Party should implement rigorous environmental impact assessment procedures for mining activities outside the property but which have the potential to negatively impact on its Outstanding Universal Value, to avoid such impacts.

The Delta has been inhabited for centuries by small numbers of indigenous people, living a hunter-gatherer existence with different groups adapting their cultural identity and lifestyle to the exploitation of particular resources (e.g. fishing or hunting). This form of low-level subsistence use has had no significant impact on the ecological integrity of the area, and today mixed settlements of indigenous peoples and later immigrants to the area are located around the fringes of the delta, mostly outside the boundaries of the property. Continued special attention is needed to reinforce the recognition of the cultural heritage of indigenous inhabitants of the Delta region. Ongoing efforts should focus upon sensitively accommodating traditional subsistence uses and access rights consistent with the protection of the property’s Outstanding Universal Value. Efforts should centre on ensuring that indigenous peoples living in the property are included in all communication about the World Heritage status of the property and its implications, that their views are respected and integrated into management planning and implementation, and that they have access to benefits stemming from tourism.

The State Party is encouraged to address a range of other protection and management issues to improve integrity. These include enhanced governance mechanisms to empower stakeholders in the management of the property; the development of a property specific management plan which harmonizes with planning in the wider landscape; ensuring adequate staffing and funding to build the capacity of the Department of Wildlife and National Parks; and programmes to strengthen the control and elimination of invasive alien species from the property.