Do Protected Areas Conserve Neotropical Freshwater Fishes? a Case Study of a Biogeographic Province in Venezuela

Do Protected Areas Conserve Neotropical Freshwater Fishes? a Case Study of a Biogeographic Province in Venezuela

Animal Biodiversity and Conservation 34.2 (2011) 273 Do protected areas conserve neotropical freshwater fishes? A case study of a biogeographic province in Venezuela D. Rodríguez–Olarte, D. C. Taphorn & J. Lobón–Cerviá Rodríguez–Olarte, D. Taphorn, D. C. & Lobón–Cerviá, J., 2011. Do protected areas conserve neotropical fresh- water fishes? A case study of a biogeographic province in Venezuela. Animal Biodiversity ad Conservation, 34.2: 273–285. Abstract Do protected areas conserve neotropical freshwater fishes? A case study of a biogeographic province in Venezuela.— The effectiveness of protected areas to conserve freshwater fishes is limited because these areas are not usually congruent with regional patterns of fish species richness and distribution. We compared the richness, distribution and abundance of coastal freshwater fishes in a biogeographic province of Venezuela to determine their conservation status. We also estimated the relevance of existing protected areas in conserving fishes in different physiographic units and tributaries by evaluating species richness and distribution. The ichthyofauna (72 spp., ~30% endemic, ~10% threatened) was distributed according to orography, drainage and physiographic units. Most protected areas had limited effectiveness for fish conservation, mainly because they were too small or included only fragments of tributaries or drainages, or because they were located only in highland drain- ages where species diversity was minimal. To adequately protect freshwater fishes in this province the existing protected areas should be modified and expanded. Key words: Aquatic biodiversity, Biogeographic province, National parks, Coastal rivers. Resumen ¿Las áreas protegidas conservan los peces continentales neotropicales? un caso de estudio para una provincia biogeográfica en Venezuela.— La efectividad de las áreas protegidas para la conservación de peces continentales es limitada ya que generalmente estas no son congruentes con los patrones regionales de la riqueza y distribución de las especies de peces. Como caso de estudio comparamos la riqueza, distribución y abundancia de la ictiofauna en ríos costeros de una provincia biogeográfica de Venezuela para determinar su estatus de conservación. Además, también estimamos la efectividad de las áreas protegidas para la conservación de la ictiofauna según la riqueza y distribución de especies en diferentes unidades fisiográficas y afluentes. La ictiofauna (72 spp., ~30% endémicas; ~10% amenazadas) se distribuyó acorde con la orografía, cuencas y unidades fisiográficas. La mayoría de áreas protegidas evidenciaron una efectividad baja para la conservación de peces, principalmente porque eran muy pequeñas o incluían sólo fragmentos de afluentes o cuencas, o porque estaban localizadas en zonas de montaña, donde la diversidad de especies era mínima. Para proteger con eficacia adecuada a los peces continentales de la provincia, las áreas protegidas existentes deberían ser modificadas y expandidas. Palabras clave: Biodiversidad acuática, Provincia biogeográfica, Parques nacionales, Ríos costeros. (Received: 15 II 10; Conditional acceptance: 16 IX 10; Final acceptance: 22 VI 11) Douglas Rodríguez Olarte, Colección Regional de Peces, Lab. de Ecología, Depto. de Ciencias Biológicas, Decanato de Agronomía, Univ. Centroccidental Lisandro Alvarado–UCLA, Ap. postal 400, Barquisimeto (Lara), Venezuela.– Donald C. Taphorn, 1822 North Charles Street, Belleville, IL, 62221, USA.– Javier Lobón Cerviá, Museo Nacional de Ciencias Naturales–CSIC, Depto. de Ecología Evolutiva, c/. José Gutiérrez Abascal 2, 28066 Madrid, España (Spain). Corresponding author: Douglas Rodríguez Olarte. E–mail: [email protected] ISSN: 1578–665X © 2011 Museu de Ciències Naturals de Barcelona 274 Rodríguez-Olarte et al. Introduction endemics. Several protected areas have been cre- ated in the WCP (ABRAE, or areas under special Areas protected for conservation are often set up on the administration regime). These include national parks basis of available regional inventories of landscapes, and natural monuments. In our study area these biogeographic patterns of terrestrial biota, or the need comprise mainly mountain regions, a few wildlife to protect populations of specific, usually terrestrial, refuges in lowland areas near river deltas, and areas species. A lack of complete biogeographic records adjacent to marine parks. Also, in the wcp, two areas often leads to the creation of protected areas that are of special interest for the conservation of biodiversity later found to exclude important habitats and species, come together: the Tropical Andes Hotspot (Myers et and thus limit their relevance for conservation. This al., 2000), which includes several terrestrial ecore- lack of foresight is most evident and worrisome when gions (Olson & Dinerstein, 2002) and the Caribbean considering freshwater ecosystems and their fish Freshwater Ecoregion of South America and Trinidad fauna. Information about fishes is not usually taken (Abell et al., 2008). into consideration when designing park and refuge Recent work in the wcp shows that most aquatic systems. This is paradoxical since today we know that ecosystems and their fishes are at risk and several freshwater fishes are among the most endangered species have been listed as threatened (Rodríguez species on the planet as a result of habitat loss and & Rojas–Suárez, 2008; Rodríguez–Olarte et al., degradation, water pollution, species invasion and 2007; 2009). Since the distribution patterns of fish climate change (Abell et al., 2009). species vary within drainage and even more so Terrestrial protected areas have been shown to within a biogeographic province, we hypothesised have inadequate design and coverage to sufficiently that the current protected area network of this bio- conserve aquatic ecosystems (Herbert et al., 2010; geographic province did not adequately protect the Barletta et al., 2010). The situation is dire in the variety of aquatic ecosystems and the fishes found Neotropics where the largest diversity of freshwa- there. To design a project that would systematically ter fishes occurs, but our scant knowledge of fish document this, we evaluated the protected areas taxonomy, biology and ecology hinders the design of the wcp as a case study, with respect to the of effective strategies for their conservation. Thus, freshwater fishes, incorporating both historical and many protected areas in South America include only recent records for fish species distribution. fragments of watersheds or streams and so fail to include essential regions necessary to guarantee the continuity of hydrosystem function and maintenance Methods of freshwater biodiversity. Conservation biologists have a serious interest in Historical records, fish sampling and geographical determining how to best evaluate the effectiveness data of protected areas, but freshwater hydrosystems and fishes have only recently been taken seriously We used museum collections (cpucla, mbucv, into account. Newer methods now include a simple mcng and mhnls) and published accounts to quantification of fish distribution coverage, fresh- obtain historical records of fish distribution in the water habitat features and their relationships with province (Reis et al., 2003; Rodríguez–Olarte et al., attributes of protected areas or drainages (Herbert 2009). We also consulted records from databases et al., 2010; Nogueira et al., 2010) and the use of (Froese & Pauly, 2010). We estimate that the his- rarity, vulnerability or conservation indices for fishes torical records thus obtained would be sufficient in (Abellán et al., 2005; Bergerot et al., 2008). Most the wcp to delimit species distributions. We also evaluations are applied to a specific tributary or considered that data on fish abundance of historical drainage, and few take the regional biogeographic records are from sufficiently long–term observations context into account. In biogeographic provinces, bi- to infer tendencies in variation for most species and otas have evolved together, and they show patterns most drainages. and gradients of species richness and distribution We collected standardized samples from 32 different that differ at different scales (Whittaker & Fern- sites (fig. 1) among drainages of the Andes (Tocuyo), ández–Palacios, 2007). Evaluations of protected Coastal (Aroa, Yaracuy, urama) and Coriano mountain area systems that take biogeographic context into ranges (Ricoa, Hueque, Coro, Mitare and Tucurere). consideration will provide more useful information At each locality, the sampling transect was about 50 m for effective conservation. long and less than 1.5 m deep. We used electroshock- The Western Caribbean province (wcp) –a zo- ing gear with hand nets and seines to capture fishes ogeographic unit proposed to delimit the freshwater in three successive passes (Lobón–Cerviá, 1991). fishes of coastal Caribbean drainages in Venezuela– We collected samples (n = 120) from foothills and includes streams that originate in the high Andes mountain streams, concentrating efforts towards the Mountains, the arid hills of the Coriano range and end of the wet and dry seasons (September–October humid valleys in the limits of the Coastal range (Ro- and February–March) from 2005 to 2007. dríguez–Olarte et al., 2009). This set of drainages We also collected fish samples at other sites (207 lo- comprises only around 30,000 km2 but it includes a calities, fig. 1), most frequently from the foothill flood- remarkable variety of

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