Araya and Paria xeric scrub

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Araya Peninsula, Sucre, Venezuela. (Source: Photograph by Luke Mastin)

Introduction

Included in the large coastal area of the Caribbean, the Araya-Paria xeric scrub ecoregion occupies the arid zones of Araya-Paria peninsula, with the exception of the montane areas of the Paria side. The montane areas of Paria are included in the Cordillera de la Costa ecoregion. Aria-Paria also includes the island of Margarita (all except the mangroves), and extends south on to the mainland to Cumaná. The Araya-Paria xeric scrub ecoregion is characterized by very dry environments, and constitutes one of the last refuges for a number of rare and restricted-range animal species.

Location and General Description

caption WWF

Oriented from east to west, the island of Margarita is located at 38 kilometers (km) north of Araya peninsula and has a total area of 934 square kilometers (km2). The island is made up of two regions joined by an isthmus. The eastern part is the larger, where there is a massive mountain center with a high peak, the Cerro Copey, at 910 meters (m) in altitude. The Cerro Copey is surrounded by mid-height peaks separated by depressions and valleys. The western part of the island is the Peninsula of Macanao, where there is a row of mountains oriented from east to west, and reaching their highest altitude at the Cerro Macanao, 740 meters in altitude. Between these regions is an extended coastal plain that forms several sandy beaches, dunes, and salinas.

The northern coastline of the Araya-Paria peninsula, is a rectilinear and rocky littoral zone that is 370 km long. The coastline breaks at the Morro de Chacopata, an ancient island now joined to the mainland in the Araya peninsula. The western section of the Araya peninsula is characterized by a long, sandy plain that is frequently inundated by sea water, forming the extensive Araya salina. From this point, a series of low hills that increase in altitude from west to east, reach their highest point midway along the peninsula, in Cerro San José (1,104 m). To the east, these mountains are separate by low lands from the mountains of the Paria peninsula, which belong to the Cordillera de la Costa montane forest ecoregion. To the south, the Cariaco-Yaguaraparo isthmus joins the peninsula to the mainland. The mountains decrease in altitude and continue irregularly towards Cumaná. The coastline from the tip of the Araya peninsula to Cumaná encloses the Gulf of Cariaco.

The area occupied by the ecoregion is considered to be part of the Cordillera de la Costa, and to have its origins in the Tertiary. Geologically, it consists mainly of schist and gneisses underlain in some parts by granites. Soils are predominantly entisols and ultisols.

Climatic conditions along this ecoregion are very variable. In the coast, between Carúpano and Cumaná, there are two times of peak rainfall during the year; one from June to August, and the other at the end of the year. Rainfall ranges between 900–375 millimeters (mm), decreasing from east to west. In the Margarita island, there are the same two times of peak rainfall, but with annual average rainfall ranging from 250 mm in the lowlands to 1,000 mm in the Cerro Copey. The Araya peninsula area is very arid, with an annual average precipitation of 200–300 mm, and very irregular rainfall that tends to accumulate at the end of the year. In Paria, annual rainfall ranges from 900–2000 mm throughout the year. Along the coastline, rainfall tends to be lower. Average temperatures range from 26–27 °C, but can be higher in Araya and the dry lands of Margarita. Lower temperatures prevail in Cerro Copey and the moist valleys and mountains around it.

According to Huber and Alarcón, vegetation of the coastal range of Margarita and Araya-Paria peninsula, including the coast of the isthmus and mainland, is characterized by halophytic and psamophylic coastal herbs, and littoral xerophytic thorn scrubs. Halophytic coastal herbs are low-height, open communities that are found in depressions frequently inundated by sea water. This kind of habitat is poor in plant species; the most common are represented by Atriplex pentandra, Heterostachya ritteriana, Salicornia fruticosa, Batis maritima, and Sesuvium portulacastrum. Psamophylic coastal herbs are also low height communities, from open to dense, that cover sandy dunes of the beaches. Poor in plant species; the most characteristics examples are: Scaevola plumieri, Portulaca pilosa, Cakile lanceolata, Cyperus planifolius, Sporobolus virginicus, Ipomoea pes-capreae and Euphorbia buxifolia.

Littoral xerophytic thorn scrubs are low- to mid-height communities (0.5–5 m) of variable density. The communities are characterized from open, to very closed. There are strongly armed columnar cacti and spiny shrubs. These communities develop above rocks and sandy subtracts, adjacent to the beaches, between 50–100 m in altitude. The most characteristic flora is represented by Prosopis sp., Cercidium sp., Bourreria cumanensis, Ritterocereus griseus, R. deficiens and Opuntia caribaea.

The low-height deciduous forests of mainland and Paria peninsula, are middle-density forests with relatively well developed understories. Around Turimiquire massif, some frequent species are: Taebuia billbergii, Bourreria cumanensis, Bauhinia aculeata, Pereskia guamacho and Bursera simaruba. In Paria, Diospyros inconstans, Capparis coccolobifolia, Maytenus sieberiana and Jacquina revoluta are dominant.

Flora of the Cerro Copey and adjacent mountains is very similar to that of the Cordillera de la Costa montane forest. As in other montane ranges, the distribution of vegetation follows an altitudinal zonification. Between 200–500/600, relatively dense semi-deciduous low to mid forest (10–25 m) is present, and Tabebuia billbergii, Aspidosperma vargasii, Bursera simaruba, Croton xanthochloros, Clusia major, Maytenus karstenii, Coccoloba coronata, Machaerium roboniifolium, Ximena americana, Neea anisophylla are common species. Submontane evergreen forest, betweens 500–750/800 m, are of low- to mid- (10–20 m) density with 1–2 layers; they have a well developed understory and abundant epiphytes and palms. Frequent species are: Taebuia chrysantha, Myrcianthes compressa, Margaritaria nobilis, Guapira ofersiana, Nectandra coriacea, Dendropanax arboreus, Inga macrantha, Eutherpe karsteniana and Bactris setulosa. The montane evergreen shrub is made up of low shrubby-herbaceous vegetation from 1–3 m height, present above 750 m. Common examples are: Clusia flavia, Blakea monticola, Clidemia hirta, Macleania nitida, Rapanea guayanensis, and Glomeropitcairnia erectiflora.

Although, the montane forests of Cerro Copey are similar to the Cordillera de la Costa montane forests, they show a low degree of endemism. Until now, only 6 endemic species, Mikania johnstonii, Argythamnia erubescens, Croton margaritensis, Clerodendrum margaritense, Blakea monticola and Inga macrantha, have been described.

Biodiversity Features

Excluding the Cerro Copey montane forest, the species composition of these ecoregions is common to other xerophytic regions of the Caribbean. Here, neither great species diversity nor endemism are found. Nevertheless, this ecoregion is considered very important in terms of conservation, because it constitute a refuge for a number of restricted-range species that exploit very specific habitats along them.

The peninsula of Macanao and the tip of the Araya peninsula are considered by Wede and Long, as key areas for threatened birds in the Neotropics, especially due the presence of the very endangered Yellow-shouldered Amazon (Amazona barbadensis). Found in few localities of the arid zones of Venezuela and the islands of La Blanquilla, Margarita and Bonaire, and already extinct in Aruba and possibly in Curazao, this species is seriously threatened by pet trade and habitat destruction. Silvius, estimated that the population in Macanao peninsula was only about 700–800 individuals. A Margaritan subspecies of parrot, the Margarita s blue-crowned Parakeed, (Aratinga acuticaudata neoxena), occurs in the arid zones around the mangroves of La Restinga lagoon, and is also severely threatened by pet trade.

The large complex of lagoons around Cumaná, the large salina of the Golf of Cariaco and the lagoons along the Araya peninsula, (sometimes adjacent to populated areas), are refuges to many bird species. The Laguna of Chacopata, one of the best studied in terms of aquatic organisms and associated avifauna, gives refuge to the largest Pelican colony in Venezuela. Also, for several years, great groups of flamingos have been seen arriving.

Many sandy beaches along the eastern portion of Margarita and Macanao Peninsula, are permanent or occasional reproduction sites for the loggerhead (Curette caretta), and Green turtles (Chelonia midas). In Venezuela, the Leatherback turtle (Dermochelys coriacea) has its principle nesting zone along the northern coast of Paria peninsula, where densities of 2.8 nests/km2 have been recorded.

Finally, the humid region of Cerro Copey contains many ancient introduced species that are considered subspecies of those found in Margarita. Some examples of Margaritan subspecies are: the Margarita s Cotton-tail rabbit, Sylvilagus floridanus margaritae, and the Margaritan monkey Cebus apela margaritae.

Current Status

Protected areas have been created in Margarita Island around the most notable ecosystems: Cerro Copey National Park (7,130 hectares [ha]), Cerro Matasiete, and Guayamurí Natural Monument. They cover the major area of forest found in the island. La Restinga National Park (18,862 ha) covers mangroves, some arid areas around it, and portions of the northern Macanao peninsular coasts. Laguna de Las Marites Natural Monument protects other portions of mangroves and it surrounds Las Tetas de María Guevara Monument, (which also covers a small portion of dry lands around it). Nevertheless, effective protection of these areas has still not been reached according to the governmental institution of National Parks (INPARQUES).

The major area of the Macanao peninsula still remains unprotected. Although many efforts have been directed to create a Fauna Refuge, the proposal has not yet been approved by the governmental environmental agency (Ministerio del Ambiente). In the non-protected areas, all land is property of private individuals and companies, most of which exploit the sand and gravel found around the stational streams (the typical habitat of the Yellow-shouldered Amazon). The Araya peninsula and lagoons remain unprotected.

Types and Severity of Threats

All xerophytic vegetation in both Araya and Macanao is under strong pressure from overgrazing by goats. Lowlands areas of Macanao, especially those around stational streams, have been intensively deforested and destroyed for sand exploitation. A new type of adventure tourist package includes long treks in vehicles across the areas of La Restinga National Park, in trails that are banned to use. Many of these cars are driven along the beaches and destroy turtle nests.

The exploitation of salt in the tip of the Araya peninsula constitutes a focus of urbanization and a permanent threat to the xeric ecosystem. Lagoons around Cumaná are severely threatened by pollution, introduction of exotic species, and urbanization.

Despite efforts made to reduce massive catch and trade of Yellow-shouldered Amazon and Margarita s blue-crowned Parakeet during their reproductive season, it is still part the way of life of many residents of Macanao peninsula. These species may be threatened with extinction within a few years. Hunting of rabbits and iguana is also common among local people.

The most important conservation actions are those directed to create protected areas in the Araya and Macanao peninsulas. More restrictions in the exploitation of salt and sand should be imposed. Supervision efforts by authorities must be taken extremely seriously. Protection in National Parks needs to be improved.

Exploitation and trade of wildlife is a more complex problem that needs a holistic solution. This must include not only effective protection of nest areas and punishment of the traders, but also social and anthropological studies focused to create alternative economic sources for the population, sustained by a program of environmental education.

Justification of Ecoregion Delineation

The xeric habitats of the Araya and Paria Peninsula represent a region of isolation and subsequent species endemism. Our linework was derived from Huber and Alarcon, and includes the island of Margarita. From the aforementioned classification, we lumped the following vegetation types into this ecoregion from the Araya and Paria Peninsula and vacinity: "halophyllic and psamophyllic littoral grasslands", "littoral xeric shrublands", and "low evergreen xeric forests".

Additional information on this ecoregion

Further Reading

  • Forshaw, J.M. 1978. Parrots of the World. Lansdowne, Melbourne. ISBN: 0691092516
  • Huber, O. and C. Alarcon. 1988. Mapa de Vegetación de Venezuela. 1:2,000,000. Ministerio del Ambiente y de los Recursos Naturales Renovables. The Nature Conservancy. Caracas, Venezuela.
  • Huber, 1997. Bosques montanos de la Cordillera de la Costa. In: Identificación de vacíos de información botánica para la conservación de la biodiversidad en América Latina y el Caribe. Memorias del taller llevado a cabo entre el 7 y el 9 de abril de 1996 en Washington D.C. y consultas con los especialistas de la región.
  • Huber, O. 1999. Ambientes Fisiograficos y vegetales de Venezuela. In: Vertebrados de Venezuela. La Marca, E., editore. Museo de Ciencia y Tenología de Mérida. Merida, Venezuela.
  • Lentino, M., and A.R. Bruni. 1994. Humedales Costeros de Venezuela: Situación Ambiental. Sociedad Conservacionista Audubon de Venezuela, Caracas.
  • Linares, O. 1998. Mamíferos de Venezuela. Sociedad Conservacionista Audubon de Venezuela. Caracas.
  • PDVSA. 1995. Imagen de Venezuela, una visión espacial. Third edition. Petróleos de Venezuela, S.A. Caracas, Venezuela. ISBN: 980259475X
  • Rodriguez, J.P. and F. Rojas-Suarez. 1997. Libro rojo de la fauna venezolana. Second ed. Provita, Fundación Polar, Wildlife Conservation Society, Profauna-M.A.R.N.R., UICN. Ex Libris, Caracas.
  • Rojas-Suárez, F. 1994. Situación Actual y Aspectos de la Biología del Ñángaro, (Aratinga acuticaudata neoxena) en la Isla de Margarita. Pages 57-63 in G. Morales, I. Novo, D. Bigio, A. Luy, and F. Rojas-Suarez, editors. Biología y Conservación de los Psitásidos de Venezuela. Sociedad Conservacionista Audubon de Venezuela, Estación Biologica de Rancho Grande, EcoNatura, Sociedad Científica Parque Nacional Henri Pittier, Provita. Caracas.
  • Silvius, K.M. 1989. Resultados Preliminares del Proyecto Ecología, Biología, y Situación Actual de la cotorra (Amazona barbadensis: Psittacidae) en la Isla de Margarita, Nueva Esparta. Informe para la Fundación para la Defensa de la Naturaleza (FUDENA), Caracas.
  • Stattersfield, A.J., M.J. Crosby, A.J. Long, and D.C. Wege. 1998. Endemic Bird Areas of the World. Priorities for Biodiversity Conservation. Birdlife Conservation Series No. 7. BirdLife International. Cambridge, U.K. ISBN: 1560985747
  • Steyermark, J.A. 1979. Plant refuge and dispersal centres in Venezuela: their relict and endemic element. Pages 185-221 in K. Larsen and L.B. Holm-Nielsen, editors. Tropical Botany. Academic Press. Great Britain, London. ISBN: 012437350X
  • Wege, D.C. and A.J. Long. 1995. Key Areas for Threatened Birds in the Neotropics. Bird Conservation Series No. 5. BirdLife International. Cambridge, U.K. ISBN: 0946888310

 

 

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Citation

Fund, W. (2014). Araya and Paria xeric scrub. Retrieved from http://www.eoearth.org/view/article/150170

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