Ana səhifə

A biodiversity Vision for the upper Paraná Atlantic Forest Ecoregion

Yüklə 11.55 Mb.
ölçüsü11.55 Mb.
1   2   3   4   5   6   7   8   9   ...   18


The Biodiversity Vision as a tool for implementing Ecoregion Conservation

The cornerstone of ERC is a Biodiversity Vision that goes far beyond the current configuration of protected sites and management practices. To conserve the full range of biodiversity in most terrestrial ecoregions over the long term, conservation areas will need to be much larger and more numerous than what currently exists on the map today. In addition to putting more natural habitat under protection, other related conservation activities – more sustainable use of natural resources, protection of watersheds, establishment of strong NGOs, supportive legislation, environmental education – need to be greatly expanded in scope and effort. Thus, in every ecoregion, we ask from a conservation perspective, “What should the ecoregion look like in 10, 20, and 50 years hence?” This creation of a Biodiversity Vision highlights our commitment to the restoration of biologically valuable but degraded landscapes, strong legislation and enforcement programs that protect native biodiversity, and the nurturing of an ecoregion-wide conservation movement.

All of these actions take time to develop. Thus, the Biodiversity Vision requires us to plan conservation activities over larger spatial and longer temporal scales than in the past. Conservationists are challenged to define what success looks like in the context of conserving an ecoregion´s biodiversity in order to create a Vision. This picture of success depends greatly on the biological assessment as it gets refined. Too often, we confine our efforts to protecting isolated sites rather than developing a more far-reaching strategy for successful conservation at an ecoregion scale.

Without the Biodiversity Visions, ERC is only an incremental improvement over existing approaches. The creation of a Vision, as well as the implementation of an ecoregion conservation strategy, depends on the active involvement of many, in particular: host governments, experts of many disciplines, local conservation groups, development organizations, and citizens of countries within an ecoregion. WWF´s role will vary in each ecoregion, and throughout the life of an ecoregion conservation initiative. ERC highlights the conservation of ecological processes, important evolutionary phenomena, higher order diversity (generic and family), and rare habitat types as well as the more traditional taxonomic indicators of priority-setting - species richness and endemism.

In ERC biological analysis, we highlight intact or near-intact large vertebrate assemblages as vital conservation targets because of their increasing rarity worldwide. Target areas and landscapes that support or, with moderate restoration efforts, could support assemblages of megafauna such as top predators, megaherbivores, and keystone species are identified. Top predators, such as jaguars, mountain lions, wolves, lions, tigers, and snow leopards, help to control native herbivore populations. Megaherbivores, such as elephants, giraffes, hippos, and rhinoceroses, influence habitat structure through their trampling, browsing, and grazing. Keystone species, such as sea otters, fig trees, or keystone herbivores such as beavers, bison, deer, and prairie dogs – are species whose removal or decline in an ecoregion would have a disproportionate negative effect on the persistence of other species. We also highlight the critical importance of less conspicuous invertebrates and diminutive vascular plants – the taxonomic units most numerous in species in any terrestrial ecoregion.

Finally, a smaller goal of ERC is to reduce overarching threats to biodiversity that operate over multiple areas within the ecoregion (and sometimes outside of an ecoregion) rather than on a site-by-site basis.
From: Dinerstein et al. 2000. A Workbook for developing biological assessments and developing Biodiversity Visions for ecoregion conservation. Part I: Terrestrial Ecosystems. WWF-Conservation Science Program.

WWF cannot work simultaneously in all of the more than 200 ecoregions within the Global 200, and so has selected a subset of ecoregions on which to currently focus its efforts as an international network. The Atlantic Forests of South America is one of these focal ecoregions. This document presents a Biodiversity Vision for one of the ecoregions of the Atlantic Forests Ecoregion Complex, the Upper Paraná Atlantic Forest. It also provides a technical description of the analyses undertaken to arrive at this ambitious Vision. The Biodiversity Vision is aimed at laying the foundation for long-term (50 to 100 years) biodiversity conservation in the Upper Paraná Atlantic Forest. It is meant to capture the major elements of biodiversity and serves as a fresh organizing concept from which to frame actions, projects, trade-offs, threats, opportunities, partners, and stakeholders. The Vision highlights areas in which special attention should be paid to factors such as land- and resource-use planning, watershed management, and social and economic development.
Figure 1. The Global 200 Terrestrial Ecoregions

Chapter 2

The Upper Paraná Atlantic Forest Ecoregion

The Atlantic Forests Ecoregion Complex

The Atlantic Forests Global 200 Ecoregion Complex of Brazil, Paraguay, and Argentina (hereafter referred to as the Atlantic Forest), is composed of 15 ecoregions, and is among the most endangered tropical rainforests in the world, with just 7.4 percent of its original 1,713,535 square kilometers of forest cover intact. The Atlantic Forest extends from a tropical latitude in the states of Ceará and Río Grande do Norte on the northeast coast of Brazil, to a highly seasonal subtropical latitude in the southern state of Río Grande do Sul in Brazil. It extends from the Atlantic Ocean westward to the interior over Brazil's coastal mountain range to the watershed of the Paraná River in eastern Paraguay and to Misiones Province of Argentina (Figure 2).

The biodiversity of the Atlantic Forest is not evenly distributed since different combinations of temperature, altitude, soils, rainfall, and distance to the ocean along its range have created conditions for unique groups of species to evolve in localized areas. The forest retractions and expansions of the geologically recent Pleistocene period may have contributed to the creation of new species and have shaped the actual distribution of the species of the Atlantic Forest (Prance 1982 in Tabarelli et al. 1999). To design a conservation strategy that would ensure the long-term survival of a representative sample of the complex biodiversity of the Atlantic Forest, WWF scientists and partners have divided the Atlantic Forest into 15 ecoregions for analysis to identify biological goals and long-term conservation strategies to achieve them (Figure 3).

In spite of its highly fragmented condition (Figure 4), the Atlantic Forest remains one of Earth’s most biologically diverse ecosystems, containing about 7% of the world´s species (Quintela 1990 in Cullen et al. 2001). One of the world´s highest diversity of woody plant species per hectare has been recorded in the Atlantic Forest, in the State of Bahia, with 450 species of trees (>10 cm dbh) per ha. Not only its biodiversity characterizes the Atlantic Forest, but its high level of endemic species (those found nowhere else on earth) is astonishing and makes this ecoregion complex a high priority for conservation. Forty percent (8,000 species – 2.7% of all plants on the planet) of the Atlantic Forest’s 20,000 plant species are endemic. Forty-two percent (567 species – 2.1% of the Earth’s terrestrial vertebrates) of the Atlantic Forest’s 1,361 terrestrial vertebrates are also endemic (Myers et al. 2000). Over 52% of the Atlantic Forest’s tree species, 74% of its bromeliad species, 80% of the primate species, and 92% of its amphibians are endemic (Mittermeier et al. 2001, Quintela 1990 in Valladares-Padua et al. 2002). Many of these species are now threatened with extinction. Of all the species recognized as endangered in Brazil, nearly three-quarters live in the Atlantic Forest (Bright & Mattoon 2001). It is not a surprise that the eight Brazilian species considered extinct in recent times were all endemic to the Atlantic Forest (Mittermeier et al. 1999).

The Atlantic Forests Ecoregion Complex has also been identified as a Biodiversity Hotspot, first by Myers (1988, 1990) and then by Conservation International as one of its 25 Hotspots (Mittermeier et al. 1998, Myers et al. 2000). The Hotspots approach focuses on threatened areas of species endemism. BirdLife International has mapped every bird species with a restricted range of less than 50,000 square kilometers with Endemic Bird Areas significantly overlapping a large part of the Atlantic Forests Global 200 Ecoregion Complex (WWF 2000).

In addition to containing some of the world’s rarest species, what remains of the Atlantic Forest is directly associated with the quality of life of the human population. Forests are vital to watershed protection, prevention of soil erosion, and to maintaining environmental conditions necessary for the existence of cities and rural areas. In Brazil alone, the Atlantic Forest is the water reservoir for almost three-quarters of Brazil´s population. A large fraction of the electricity produced in Brazil, Paraguay, and Argentina, is produced in the rivers of the Atlantic Forest and especially in the Upper Paraná ecoregion, where two of the largest hydroelectric dams in the world are located (Itaipú and Yaciretá).

A long history of human occupation of the region is testified by the stone tools of approximately 11,000 years ago that have been found in the Atlantic Forest. When the Spaniards and Portuguese arrived in the region in the early 1500s, they found groups of people, mostly Guaraní, with an economy based on small farming, hunting, and gathering. These native people, living at low to medium densities, had at most moderate effects on the environment. However, with the arrival of the Europeans in the 16th century, a dramatic transformation of the environment began to take place in the Atlantic Forest (Dean 1995, Jacobsen in press).

As the first part of Brazil to be colonized by the Portuguese in the early 1500s, the Atlantic Forest has developed into the population hub of the country. In the 17th and 18th centuries, sugar cane, cattle raising, and uncontrolled logging for the exploitation of wood from a few tree species were the main economic activities that began to transform the Atlantic Forest into pastures and monocultures. In the 19th century, coffee plantations became increasingly common in the southern and central portions of the Atlantic Forest. In the 20th century industrial activities, especially steel production, started to consume increasing quantities of fuel-wood (Dean 1995, Bright and Mattoon 2001). Eucalyptus and other exotic monoculture forest plantations (for timber, pulp, firewood, charcoal, and other wood products) replaced huge expanses of Atlantic Forest. In more recent times, and especially in the south, soybean, wheat, corn, and other annual monocultures have definitely transformed what was a vast continuous forest into a highly fragmented landscape where small fragments of forest survive amidst a matrix of monocultures, cattle pastures, roads, and cities. Similar consequences of forest destruction occurred in all the Atlantic Forest´s Brazilian states, despite differences in the main economic activities and the timing of forest destruction. In the state of São Paulo, for example, large landowners began to exploit the forest very early in the history of Brazil, and most of the land is in the hand of a few people (Cullen et al. 2001). In the state of Santa Catarina, the destruction of the forest mostly began in the 20th century and most landowners possess small parcels (Hodge et al. 1997). Nowadays, three-quarters of Brazil’s population of 170 million lives in the Atlantic Forest and eighty percent of Brazil's GNP, the world’s eighth largest economy, is produced in this region.

In contrast, the isolation from human population centers of the Argentine and Paraguayan portions of the ecoregion has allowed the preservation of the largest piece of Atlantic Forest. The occupation of the ecoregion in Paraguay and Argentina began later, and until the beginning of the 20th century, most of the Atlantic Forest in these countries was still covered by native forest. In the last few decades, large expanses of Atlantic Forests were clearcut in Paraguay for the development of large-scale soybean plantations and small-scale agriculture. In Argentina, the colonization and development of the country began in the pampas, with one of the richest soils in the world, far from the forest. The Atlantic Forest of Misiones Province in Argentina was exploited relatively late in the history of the country, mainly for timber and yerba mate (an endemic plant used for tea).

The habitat destruction and fragmentation of the Atlantic Forest coupled with the high levels of species endemism make conservation action particularly urgent.

1   2   3   4   5   6   7   8   9   ...   18

Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur © 2016
rəhbərliyinə müraciət