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Biodiversity Conservation in Costa RicaLearning the Lessons in a Seasonal Dry Forest$

Gordon Frankie

Print publication date: 2004

Print ISBN-13: 9780520223097

Published to California Scholarship Online: March 2012

DOI: 10.1525/california/9780520223097.001.0001

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Introduction

Introduction

Chapter:
(p.1) Chapter 1 Introduction
Source:
Biodiversity Conservation in Costa Rica
Author(s):

Alfonso Mata

Jaime Echeverría

Publisher:
University of California Press
DOI:10.1525/california/9780520223097.003.0001

Abstract and Keywords

This introductory chapter is concerned with biodiversity conservation of the seasonal dry forest in the Chorotega Region in Costa Rica, focusing on the Tempisque River Basin (TRB) and the Nicoya Peninsula. It presents the region's physical, biological, and general environmental characteristics, as well as some anthrophogenic environmental effects.

Keywords:   biodiversity, conservation, dry forest, Chorotega Region, Costa Rica, Tempisque River Basin, Nicoya Peninsula

THE CHOROTEGA REGION in northwestern Costa Rica is one of the most important areas of this republic; it covers primarily the Tempisque River Basin (TRB), Nicoya Peninsula, and other nearby lands (see map 1.1). The country′s only seasonal dry forest is located here. Enjoying a climate of contrasts, varied geological formations, very attractive natural scenic areas, and a rich cultural heritage, the Chorotega region is perhaps the second most important economic region in the country, after the Central Valley (Mata and Blanco 1994), where the capital city of San José is located. Politically, this area constitutes the province of Guanacaste, with approximately 275,000 inhabitants distributed in 11 counties and an average density of 26 inhabitants per square kilometer. In addition, three counties of Puntarenas Province occupy the tip of the Nicoya Peninsula. The TRB is made up of nine counties of Guanacaste Province. The approximate population in this area is 157,000, with an average density of 30.6 inhabitants per square kilometer. Of this population, 43 percent is located in urban centers (˜60 inhabitants per square kilometer), whereas 57 percent lives in rural areas and tends to move toward cities such as Liberia, Cañas, and Nicoya (see map 1.2).

There has been a slow migration of rural and urban residents toward other parts of the country, mainly owing to lack of employment and the mechanized monocultures that require less human labor. These activities involve seasonal crops (melons, sugarcane) and are primarily carried out by a large contingent of nonresident Nicaraguans. The tourism industry in this area is one of the most important of the country.

The entire region has been notably altered and transformed, undergoing substantial changes in land use and ownership, as well as in the quality and quantity of its natural resources. The impact is a cause of concern for the region′s inhabitants, public institutions, and nongovernmental organizations, which are making efforts to prevent further damage and repair that which (p.2) has already been done. This introductory chapter presents the region′s main physical, biological, and general environmental characteristics, as well as some anthropogenic environmental effects, topics discussed in subsequent chapters of this volume.

Introduction

Map 1.1. Principal river basins of Costa Rica.

Geography

The massive mountain range system that runs along the length of Costa Rica, with a northwest–southeast orientation, creates two principal versants, or basins, with similar areas (map 1.1). The Pacific Basin covers a territory of 26,585 km2 (Herrera 1985), modeled by a network of rivers whose flow and eroding behavior are determined by marked climatic seasons. This basin, particularly the northwestern part of Guanacaste, is characterized by a dry seasonal climate, represented by the tropical dry-forest life zone (sensu Holdridge 1967; see the section “Life Zones” later in this chapter and map 1.2) with its transitions and the tropical wet forest of atmospheric association, which is characteristic of the (p.3) Nicoya Peninsula. On the other side, the Caribbean Basin has a more homogeneous and much more humid climate for most of the year. This large basin is divided into two main watersheds; in one, the rivers empty into Lake Nicaragua and the San Juan River, which in turn reach the Caribbean Sea, and in the other, the rivers empty directly into the Caribbean.

Introduction

Map 1.2. Life zones, river matrix, and important geographical points of northwestern Costa Rica.

The Guanacaste Mountain Range (Cordillera Guanacaste) separates the watersheds with a few rivers flowing to Lake Nicaragua and the San Juan River from those of the Gulf of Nicoya (Mata and Blanco 1994). The Nicoya Peninsula is located in the southern sector of Guanacaste. Along with the continental northwest, the peninsula encloses the Gulf of Nicoya, one of the most important ecosystems in the country (chapter 10). The coastal hills and mountains determine the watershed of the northwestern coastal strip, which begins at the border with Nicaragua and ends at the southern tip of the peninsula (map 1.1).

The vast region around the Gulf of Nicoya, with this common drainage, is known as the Gulf of Nicoya Basin (GNB), covering approximately 12,000 km2. The basin′s land and estuarine fluvial components are hydrologically connected with a common receptor: the Gulf of (p.4) Nicoya (see maps 1.11.3). The surface area of the GNB constitutes half of the country's entire Pacific Basin (map 1.1) and represents nearly 25 percent of the entire country (Mata and Blanco 1994: 47). The GNB has a variety of land and aquatic ecosystems comprising nearly all the life zones that occur in Costa Rica. It also features the country’s only tropical dry-forest zone. The TRB, which includes the Bebedero River, is situated here. It is the most extensive hydrological subregion of Guanacaste (5,460 km2, which represents 54% of the province and approximately 10% of the total national area). The largest extant territory of dry forest in the Pacific-side ecoregion of Mesoamerica (World Wildlife Fund/World Bank 1995), which is protected (Boza 1999), is in this subregion.

Introduction

Map 1.3. Parks, reserves, and conservation areas of Costa Rica.

(p.5) Geophysical Aspects

Climate

Precipitation in the northwestern region of the country shows a marked seasonal variation, with an average of 1,800 mm annually; the TRB has 1,746 mm of rain per year. About 95 percent of the rainfall occurs from May to November, and the dry period extends from December to April. There are recurrent periods of prolonged rains that induce extensive flooding in the lowlands of the TRB (Asch et al. 2000). The southern region of Nicoya Peninsula has the most abundant annual precipitation, between 1,800 and 2,300 mm, and the least abundant is in the central and northwestern zones of the TRB, with around 1,400 mm per year. The monthly mean temperature lies between 24.6°C and 30°C. The highest temperatures occur in April and the lowest between September and December. Strong trade winds are predominant during the dry season, with speeds between 10 and 30 km per hour and gusts of roughly 60 km per hour. Winds from the Pacific are predominant during the rainy season, bringing humidity with them, with speeds between 3 and 8 km per hour, making the Nicoya Peninsula the most humid sector of the entire region.

Geology and Geomorphology

The northwestern region of Costa Rica was formed through various processes. Notable are the volcanic and sedimentary rocks from the Mesozoic, which crop up extensively in the peninsula (Castillo 1984), as well as the Bagaces and Liberia formations and the sedimentary rocks of the Quaternary (Castillo 1983) in the TRB. The Nicoya complex, the Aguacate Group, and the Quaternary volcanic formations are included in this geological evolution, as well as recent volcanic structures that make up the Guanacaste Mountain Range (map 1.1). The Nicoya complex consists of the oldest rocks in Costa Rica, formed around 74 million years ago. In addition, the region has sedimentary formations such as Rivas, Sabana Grande, Brito, and Barra Honda. Formations of intrusive rocks and fluvial, colluvial, and coastal deposits are common, as well as swampy areas. Three main formation processes contributed to the relief in the TRB. The first is volcanic, which occurred in the northern and northeastern sectors of the area. The second, denudation, occurred in different sectors but more toward the southwestern sector. The main alluvial sedimentation forms, the result of the third process, are located in the flat and lower parts of the TRB (Bergoeing et al. 1983).

Sulfur, clays, alluviums, limestone, and diatomite are among the geological resources of Guanacaste. There have been claims of illegal exploitation of alluvial material in public-access riverbeds, and there are authorized quarries for road maintenance and construction. Geothermal energy is generated on the volcanic mountain range slopes. Seismic activity is lively throughout the province, with local faults. The subduction process of the Coco’s and Caribbean tectonic plates affects the whole country, and consequently the probability of a strong energy release is high in the entire Chorotega region.

Soils

Soils vary from volcanic types in the upper parts of the mountain range to flooding alluvial in the lower part of the TRB. The region has valleys of varying sizes, with high-fertility soils (e.g., Tempisque, Curime, Nacaome, Nosara) and poor soils (ignimbrite deposits of Liberia-Cañas). Some soils are light in texture, such as the volcanic types, and others are heavy, such as soils with a high clay content in the floodplains. Among the soil orders in the TRB are alfisols (13%), entisols (26%), inceptisols (38%), mollisols, and vertisols (TSC 1999).

Land-Use Capacity and Conflicts

The soils of Guanacaste are shallow or stony, or both, and the long dry period and strong winds (p.6) further limit their productiveness (Echeverría et al. 1998). Many sectors with small slopes are classified as lands for watershed protection, for example, north of Bagaces and Liberia and the hills of the Nicoya Peninsula. During the first half of the past century, deforestation was extensive in the entire region, but particularly in the lowlands during the period 1940–65, with the opening of the Pan American Highway. After the cattle-ranching decline, at the end of the century, and regardless of natural regeneration on many hills, the effects of tree cutting are still noticeable in the inner parts of the peninsula’s coastal mountain range.

Official data indicate that the Chorotega area has some of the highest land-use imbalances in the country. In this region 38 percent of the land—almost 600,000 ha—is overused, only 16 percent is used sustainably, and the rest is underused. In the case of the TRB, which is the flattest land in the region, 30 percent of the area is overused, 40 percent used sustainably, and 30 percent underused. Overuse brings about deterioration of soils and other resources, as is the case when cattle are kept in lands with forest capacity. An example of underuse in the basin is raising livestock in lands with the potential for agricultural activity.

A considerable part of the Guanacaste floodplains is used for agricultural purposes and for some urban and semiurban areas (such as Filadelfia and Ortega); these zones are extremely vulnerable because they include wetlands and plains with recurrent flooding (see the section “Geohazards and Disasters”). There are no ordinances for the safe construction and location of urban developments in these areas.

The main erosive process in the region is hydrological, but eolian erosion is also a problem. Because of the inadequate use of soils, the sediment load in rivers is directly related to the erosion. The most abundant production of sediments coincides with the rainy season (May to November), particularly in the hills of the Nicoya Peninsula, which become microbasins producing large quantities of water during short periods. Landslides and fast floods are frequent during the strong and sustained rainfalls of September and October, particularly under the influence of the tropical storms in the Caribbean Basin.

Hydrogeology

Groundwater is used in the entire region for human as well as agricultural, industrial, and cattle needs. The Chorotega region has 62 percent of the country’s rural aqueducts, which are supplied by wells (Echeverría et al. 1998). The principal sources are the volcanic aquifer of the Bagaces formation, which supplies water to the people of Liberia, Bagaces, and Cañas, and the colluvial-alluvial aquifer alongside the right-hand region of the Tempisque River, which supplies water to several towns and smaller population centers and may be the most important aquifer in the entire basin. Colluvial deposits in Nicoya Peninsula’s valleys can provide effective flows of up to 65 liters per second (e.g., Nosara Valley and smaller ones). Their waters are generally potable and suitable for agriculture.

Several of these aquifers could supply coastal tourist projects between Culebra and Brasilito Bays, transporting water across the TRB’s western divider and therefore diminishing risks of saline intrusion in those limited coastal aquifers. There have been documented cases of salinization from overexploitation of the northwestern coastal strip, specifically in Flamingo, El Coco, and Tamarindo and particularly in the area of Puntarenas (TSC 1983: 95), among other cases.

Hydrology

The rivers of northwestern Costa Rica can be divided into three geographical sectors: the Lake Nicaragua Basin, to the north; the northwestern coastal strip; and the GNB. In the first sector, four rivers originate in the volcanic massifs of Cerro El Hacha and Orosi Volcano, the northern extreme of the Guanacaste Mountain Range (map 1.2). These are the Sapoa, Sabalos, Mena, and Haciendas, and they empty into Lake Nicaragua. The Haciendas is the boundary between the provinces of Alajuela and Guanacaste. The largest watercourse of Guanacaste is the Tempisque River, born in the southern flanks of the (p.7) Orosi volcanic massif. Together with the Bebedero River it forms the largest watershed in Costa Rica. The western sector of the Nicoya Peninsula has low coastal sierras (50 to 250 m above sea level) where creeks and a few rivers originate, their microbasins emptying directly into the Pacific Ocean along the entire northwestern coastal strip. Most of these small streams remain dried up during the summer but rapidly grow and flood with the strong and persistent precipitation of the rainy season. All of them are born in the driest life zones of the country (see map 1.2), such as the tropical dry forest, as well as in the tropical moist and premontane wet forests.

The northwestern coastal strip is narrow compared with the TRB, which empties into the gulf, and it widens heading south in the peninsula as its mountains become higher. For example, the Cerros La Carbonera and Cerro Vista al Mar (983 m above sea level) and Zaragoza later average between 200 and 500 m above sea level all the way to the extreme of the peninsula. Although most of the rivers are nearly dry during the summer, the Nosara and Ario Rivers, the two longest and most affluent of the entire northwestern coastal strip, keep a perceptible base flow, with a more noticeable decrease in April and May. Two of the most important wetlands of the coastal strip are the outstanding Tamarindo National Wildlife Refuge (mangroves and estuary), annexed to Las Baulas Marine National Park and the Ostional National Wildlife Refuge, at the mouth of the Nosara River (map 1.3).

Water is used in many ways in the region: public supply, domestic use, agricultural irrigation, hydroelectricity generation, tourism, and industrial activities. Water services to cities and large towns are provided by the national system of aqueducts. There are rural aqueduct councils in smaller population centers, but some are continuously mismanaged, and the dispersed population obtains its water supply from artesian wells. Groundwater resources largely supply industrial and agricultural activities.

Irrigation water, used for the extensive sugarcane, rice, and melon industries, is obtained primarily by detouring rivers and creeks through the Arenal Tempisque Irrigation System. When completed, the system will service about 45,000 ha, with a water volume of 45 m3 per second. This project, the largest hydrological system in the country, consists of surface water for multiple purposes collected from the Arenal River watershed (Atlantic Basin), which passes through a tunnel to feed a cascade of three power stations on the Pacific Basin side. These power stations are part of the Arenal-Corobici-Sandillal Hydroelectric Project developed by the Costarrican Institute of Electricity. The presence of water of excellent quality in the dry-zone area has stimulated the invasion of the floodplains and many wetlands for agricultural purposes, without sufficient environmental studies. The entire area is subject to recurrent natural floods. Stream corridors are being altered, and levees, channels, and ditches have been constructed without a master plan. These and other activities are making the area highly vulnerable to environmental damage (see the section “Deforestation of Basins, Wetlands, and Stream Corridors” and chapter 9). Balance between ecological alteration and economic development of the entire region, although it seems to be positive, has not yet been studied.

Geohazards and Disasters

The main geohazards of the region are hydrometeorological; they increase during times of strong rainfall and storms, which in some instances are indirect effects of hurricanes originating far in the Caribbean but which always have strong repercussions. As a result of the vulnerability caused by uncontrolled human activity (deficient urban planning, urban invasion of lands susceptible to the effects of these strong recurring phenomena), there are damages from floods, avalanches, and landslides, as well as from hydrological erosion. They occur in the floodplains of rivers and on steep slopes, and they affect crops, bridge infrastructure, roads, and urban areas, particularly in the wetland sectors of the Tempisque, Cañas, and Las Palmas Rivers. However, these lands have been overtaken by (p.8) agricultural activities, settlements, neighborhoods, and even cities (case in point: the city of Filadelfia and areas nearby). Although the National Emergency Commission acts efficiently during disasters, there is no ordinance for appropriate and obligatory construction of houses (e.g., perched on piles) or for development of urban centers on more elevated lands. Levee construction continues along the Tempisque River without environmental studies or official restrictions.

There is a potential seismic threat throughout the entire Pacific region of the country. Volcanic hazards are present only in the sector of the Guanacaste Mountain Range, where the Rincon de la Vieja and Arenal are the only volcanoes currently having eruptions and fumaroles activity; other volcanoes show less activity.

Biological Aspects

Life Zones

The great bioclimatic diversity of the Chorotega region (map 1.2) is divided into seven life zones with various transitions. The method of classification of plant formations, or World Life Zone System (Holdridge 1967), consists of three main levels of detail. The first is the main life zone category, which considers climatic variables of annual mean precipitation and annual mean biotemperature and the potential evapotranspiration defined by the first two variables and a constant empirical value. The biotemperature is an adjustment of the annual mean temperature, in the 0°C–30°C range, at which there is supposed to be a better development of life. Each life zone has a definite range for each variable, and the plotting of these factors on a graph forms a diagram of hexagons (Hartshorn 1983). The plant association, or ecosystem, is the second level. It considers local environmental factors, such as dry periods, soils, geological relief, and prevailing winds; therefore, associations such as hydric, wet and dry edaphic, cold and warm atmospheric, and combinations of them are found. The third level is the successional stage, referring to the degree of intervention, mainly due to human activities, undergone by the original natural vegetation. It includes categories such as intervened primary forests, secondary growths and their initial successional stages, and agricultural and other matrixes in the landscape. Advantages of this system include the prediction of the type of natural vegetation that should exist in a deforested area, starting from local physical environmental factors; the prediction of carbon offsets by terrestrial biota in a determined life zone (Tosi 1997); and the analysis of possible changes in type of vegetation from climatic change.

The tropical dry-forest zones, which are strongly seasonal, and the related transitions to moist forest constitute around 30 percent of the Chorotega region. The largest remaining dry forest in the Pacific-side ecoregion of Mesoamerica (World Wildlife Fund/World Bank 1995), which is protected (Boza 1999), lies in this territory. The tropical moist forest predominates, particularly in the Nicoya Peninsula (map 1.2). The greatest biodiversity occurs in the Guanacaste and Tilarán Mountain Ranges, where several life zones are found as narrow elevational bands surrounding the volcanic mountain chain.

Protection and Biodiversity Conservation

The northwestern region of Costa Rica has three conservation areas: Tempisque (dry), Guanacaste (dry), and Arenal (midelevation/cloud forest) (map 1.3). The three manage a total of 35 wild areas that have varying protection categories, such as national parks and wildlife refuges. One of the most outstanding examples of protection is the Area de Conservación Guanacaste (ACG), covering 120,000 terrestrial and 43,000 marine ha (Janzen 2000; chapter 7). The second dry-forest conservation area, Area de Conservación Tempisque (ACT), consists of about 35,000 ha of terrestrial and wetland habitat and is still being defined and administered.

An essential part of the conservation process is maintenance of the biodiversity that is threatened by human activities. In the dry forest it is (p.9) still necessary to increase the number of protected areas and to connect them with appropriate corridors, so that all existing ecosystems and biomes of the region can be encompassed. Conservation organizations have developed outstanding protected areas (e.g., Monteverde Cloud Forest Preserve) and have been making efforts to protect other important zones already targeted for development projects; a few are nearly established, and several corridors are under consideration.

Wildlife

In general, the Chorotega region still has a rich flora and fauna. The different life zones of the area have an ample diversity of plants and animals. In the past 25 years, important sectors of the forest habitat in the Nicoya Peninsula have naturally recovered (secondary growth) after the recession of cattle ranching (TSC/CIEDES/CI 1997); many species of mammals and birds have had noticeable increases in their populations (A. Mata, pers. obs.). This is an important development because Guanacaste is one region of Costa Rica where wildlife has suffered the greatest negative impact, resulting from loss of natural habitat, overexploitation through extensive cattle ranching and agriculture (chapter 21), and hunting/poaching, particularly during the middle years of the past century. Furthermore, the hunting of sea turtles (chapter 15) and dolphins, as well as overfishing in the Gulf of Nicoya (chapter 10), has prompted legal actions for environmental protection.

There are almost 30 endangered bird species in the region (chapter 12), 12 mammal species (chapter 5), and several hardwood tree species having commercial value. On the other hand, about 20 animal species—among them birds, rodents, and mammals—are considered pests because of alleged damages done to agricultural crops and domestic animals.

The creation of protection areas, such as the ACT and ACG, and wildlife refuges or private preserves (e.g., Monteverde Cloud Forest) has brought about a change in the consciousness of the population, resulting in a slow but effective decline in faunal loss. Even so, poaching still exists, whether with temporary permits or illegally by unscrupulous people, and even fire is sometimes used to flush wildlife. Furthermore, political pressure to develop tourist facilities and hotels in national refuges is common, and there is illegal fishing during prohibited seasons. The National System of Conservation Areas (map 1.3) has recently become an instrument for implementation and interinstitutional coordination, with a geographical decentralization, and watches over integrated forestry management, wildlife, and areas for biodiversity protection. However, the system is not completely efficient, as it lacks appropriate finances and staffing.

Wetlands

These productive ecosystems are abundant in Guanacaste, particularly around the Gulf of Nicoya. Wetlands alone represent 20 percent of the area of the TRB, that is, 1,025 km2, not including the riparian area or uplands. These ecosystems present conditions of great ecological, economic, and social value, and the inhabitants of the region have exploited them throughout history. In the case of the middle TRB area, the continuous invasion of wetlands by agriculture has resulted in a large negative impact. There have also been cases of agricultural, domestic, and industrial contamination of wetlands, as well as overexploitation of their resources and the alteration of natural drainages.

The most extensive wetlands are those between 3 and 30 m above sea level, located in the floodplains of the rivers in the TRB, the so-called palustrine wetlands. Those influenced by tidal estuarine waters are located near the Tempisque River mouth (near Palo Verde; map 1.2) and surrounding the Gulf of Nicoya (Echeverría et al. 1998). Small lakes or lagoons cover a lesser area (e.g., Cañas River); the rest of wetlands are the banks of the stream corridors, which extend up to the headwaters. The natural vegetation includes herbaceous gramineae and cyperaceae shrubs, floating and submerged aquatic vegetation, rooted vascular plants, mangroves, and dry-forest trees in naturally drained areas. The (p.10) wildlife supported by different wetland types is of great environmental significance to inhabitants of the area. The government protects a few of these areas, such as the wetlands in the ACG and Palo Verde in the ACT.

Although smaller in size, other important wetlands have diverse wildlife, such as those located on the northwestern coastal strip (map 1.1). On the southern coast of the Nicoya Peninsula some remain in protected areas such as in Tamarindo and at the mouth of the Nosara River (map 1.3); they are in national wildlife refuges.

Environmental Impacts

Deforestation of Basins, Wetlands, and Stream Corridors

The disappearance of extensive forest areas and fragmentation caused by human actions has strongly affected the ecosystem of the entire region, especially lowland areas subjected to agriculture and extensive livestock use. Damage to riparian systems, which had traditionally been protected, is visible in the majority of rivers in Guanacaste—as it is nationwide. The fluvial-riparian continuum is essential to maintain biodiversity of the ecosystem (chapter 9). However, each bridge, road, or crop established along a river zone results in various degrees of fragmentation, which could be prevented by protecting stream corridors and by environmentally sensitive construction, as well as through enforcement of current laws (chapters 22 and 23). Cattle grazing in wetlands and stream corridors, which is common, is even more damaging to understory vegetation. Slum settlements, as well as expanding urbanization from main cities, have reached the natural floodplains and banks of rivers and their wetlands, resulting in undesirable environmental effects and increasing the vulnerability of those same settlements.

Although outstanding advances have been made in fire prevention, thousands of hectares in the region were affected by fires from 1997 to 1998, in part as a result of the effects of the El Niño phenomenon (Estado de la nación 1999: 189); the old custom of slash-and-burn land clearance is still a problem during the dry season.

Water Extraction By Industry, Irrigation, and Human Populations

There are several notable water consumers in the dry forest. Once they use this resource, those consumers become producers of contaminated water, in varying degrees of output. Among them are sugar industries, rice growers, coffee mills, fruit-packaging plants (melons), the Arenal-Tempisque Irrigation System, aquaculture, cities, and towns (Echeverría et al. 1998).

The sugar industry taps water from the Cañas, Liberia, and Tempisque Rivers, with volumes varying from 5 to 20 m3 per second or more for industrial and irrigation purposes. There have been shortage problems during the dry season and when the sugar harvest is ending, and it has even been necessary to obtain water from the irrigation system to satisfy the industrial demands, to the extent that in some years the Tempisque River can be easily crossed on foot by the end of the dry season. Taxes for exploitation rights are quite low, and, according to municipal authorities, there is an evident lack of controls for the amount of water pumped.

Modification of the Natural Course of the Tempisque River

Near those same industries, fluvial morphology has been altered by channeling and dam construction for water deviation and containment, as well as by intervention of riparian forests. If sugarcane expansion in these fragile areas is not regulated, there will probably be more intervention with channels, levees, and fluvial detours, which would bring about certain alteration of nearly all wetlands in this region. Water consumption during the dry season drastically changes the volume of the river, which has already been tapped upstream. There is no legislation that regulates levee or channel construction, and some residents of the area who have experienced floodings feel that this infrastructure, built without specific environmental planning, (p.11) is contributing to the prolonged containment of floodwater in the middle TRB.

Pollution: Water and Solid Wastes

The entire dry-forest region, but particularly the TRB, is subject to various types of pollution; water pollution is the most relevant, in the form of sewage, wastewater from industry and urban centers, and water from agriculture activities. The initial capacity of urban sewage treatment plants was reached some time ago, and now they cannot handle wastes produced by new urban developments (Echeverría et al. 1998; chapter 9).

Point-source pollution is generally caused by the discharge of urban wastewater, tourist developments, industry (sugar mills), mining, pig farms, tilapia aquaculture, and garbage dumpsites, among others. Aside from routine government controls of bacteriological quality of water from aqueducts and sediment monitoring of some rivers by the Costarrican Institute of Electricity, there is almost no surveillance of surface-water quality in the entire region.

The legal frame for pollution control in the country is sufficient. However, the lack of regular monitoring, failure to reinforce laws, lack of application of new technologies, and limited capacity of governmental offices in charge work against improved control of emissions. Despite this situation, several agreements have been reached between the government and the sugar industry (as well as coffee mills and pig farms) regarding the control of these industries’ liquid and solid wastes (chapter 9); a positive change has been noticed. Nonpoint sources of pollution include the use of chemicals in agricultural areas, such as in the extensive rice paddies. Almost no studies have been done on this subject. Along with the pollution from the Central Valley Basin, the contamination of the TRB has repercussions on the Gulf of Nicoya that are yet to be estimated (chapter 10).

Alteration of the Terrestrial-Maritime Zone

Certain laws protect this coastal strip, which is made up of a public area and a restricted area. The public zone consists of the first 50-m strip of land starting from the high-tide water level and all surface uncovered during low tide and includes any extension covered by estuaries, mangroves, coastal lagoons, and floodplains. The interior band of 150 m of continental or insular land constitutes the restricted zone. According to the law, both contiguous bands should be under protection and careful management with regard to urban, tourist, industrial, or agricultural developments. However, there have been serious transgressions. Several disasters have occurred since approval of the law, particularly as a result of ignorance, lassitude, or connivance involving the same municipalities in charge of surveillance of resources. Even worse, some of these disasters were the result of inaction on the part of the Ministry of Environment and Energy (MINAE) and the Tourism Ministry, which were perhaps afraid of hampering economic development. This lack of action may contribute, paradoxically, to the destruction of the natural attraction that is the driving force for tourist development and a reason for the country’s overseas environmental prestige. The problem is of special relevance in the Chorotega region: of 484 official tourism concessions and permissions registered in 1999 for the country (Estado de la nación 1999: 191), 388 were for Guanacaste Province.

Assessment of Biodiversity Conservation By Specialists

Superimposed on today’s complex dry-forest environment are the numerous biologists who have studied the extant flora and fauna, principally in Costa Rica. Working with them, directly or indirectly, are the specialists who have dealt with socioeconomic, political, and legal aspects of conserving this biota. In the chapters that follow, major players present their individual and interrelated stories on what has been learned about biodiversity and its conservation in the dry forest and beyond and what must be done in the future to better protect this biodiversity. The (p.12) authors provide the first overall assessment of how well one Central American country has examined, valued, and conserved its biological heritage.

Acknowledgments

We thank Gordon Frankie and Brad Vinson for their valuable commentaries and suggestions and Vladimir Jimenez at the Tropical Science Center for the preparation of maps.

References

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