Selection of Priority Areas for Fish Conservation in Guadiana River Basin, Iberian Peninsula

Abstract

We developed a species-by-species approach for selecting protected areas for conservation of native freshwater fishes in semiarid regions, with catchment as the fundamental landscape unit for conservation efforts. Input data were composed of occurrences of freshwater fishes and landscape variables, and general quantification of occurrence, abundance, and endemicity of each fish species, to derive an index of conservation value for each species. Probability of occurrence of each species was performed with logistic-regression analysis based on the landscape variables and extrapolated to the entire study area with a geographic information system. We estimated the conservation value of a stream reach by summing the predicted probability of occurrence of each species multiplied by its corresponding conservation value. To define and select reserves, we used a threshold that maximizes conservation value of the stream reaches but identifies the minimum number of reaches for protection. The approach was applied to native freshwater fishes in the Guadiana River basin (southern Iberian Peninsula), which are threatened by the construction of two major dams. We used the data from 1 sampling year (1999) to produce the models, which were validated based on data collected in 2000 and 2001. We used variables of climate (3), geomorphology (4), hydrology (7), and human influence (6) to build the predictive models, which revealed that native species occur over a wide range of riverine habitats, with stream order and location in the basin the most frequently selected variables. The conservation value of species varied considerably, with Anaecypris hispanica the highest-ranked species. The catchments selected for reserves were the mainstream of the Guadiana River (upstream and downstream of the Alqueva and Pedrogão reservoirs) and the Degebe, Ardila, and Enxoé catchments. Our approach is a pragmatic way to address the urgent need to protect Guadiana native fish species in light of the ongoing anthropogenic degradation of aquatic environments.Selección deÁreas Prioritarias para la Conservación de Peces en la cuenca del Río Guadiana, Península Ibérica Resumen: Desarrollamos un método especie-específico para seleccionaráreas protegidas para la conservación de peces nativos de agua dulce en regiones semiáridas, con la subcuenca como unidad paisajística fundamental para los esfuerzos de conservación. Los datos de entrada fueron las ocurrencias de peces de agua dulce y las variables de paisaje, una cuantificación general de la ocurrencia, abundancia y endemicidad de cada especie piscícola para obtener uníndice del valor de conservación para cada especie. La probabilidad de ocurrencia de cada especie se obtuvo con análisis de regresión logística basado en las variables del paisaje y extrapolado a toda elárea de estudio con un sistema de información geográfica. Estimamos el valor de conservación de un tramo sumando la probabilidad de ocurrencia de cada especie multiplicado por su valor de conservación correspondiente. Para definir y seleccio...

Addressing longitudinal connectivity in the systematic conservation planning of fresh waters

“…A whole basin approach has been followed in this study while previous efforts in the same area were only focused on the Portuguese (Filipe et al, 2004) or Spanish (Hermoso et al, submitted) portions of the basin while cross-boundary conservation management seems a more effective practice. The most irreplaceable area and the best solution when setting the CP at high values were especially focused on a single subbasin (Chanza River).…”

“…Sampling was conducted once at every site without C o p y f o r R e v i e w block-nets in stretches of 100 m (when possible). This protocol is recommended for obtaining an accurate characterization of species´ presence-absence in the same area (Filipe et al, 2004). The sampling stretch was representative of all the habitats present in the area, including pools and riffles where available.…”

The importance of land use/land cover data in fish and mussel conservation planning

“…Each measure is described in detail below. Our methodology was based on a technique developed by Filipe et al (2004). However, in the current study we added a measure of connectivity, added a measure of species trend and quantified endemism more explicitly.…”

“…Once calculated, we standardized the CI to range between 0 and 100. Following the methods of Filipe et al (2004), a cumulative-frequency curve of increasing CI values was used to define the threshold for selection of reaches as focal areas for conservation. This technique is designed to optimize the relationship between CI and the number of reaches selected for conservation.…”

The impact of wildfire on stream fishes in an Atlantic-Mediterranean climate: evidence from an 18-year chronosequence

“…Although characterized by low taxa richness, upland tributary streams are largely free from invasive species and their associated impact on native fauna (Magalhaes et al, 2002;Clavero and Garcia-Berthou, 2006). Upland streams therefore provide important refugia for native species and represent river habitats of high conservation value (Ribeiro et al, 2000;Filipe et al, 2004;Ribeiro et al, 2009). As these upland landscapes are particularly susceptible to large-scale wildfire (Amorim et al, 2011) and because the ecological impact of wildfire is inversely proportional to stream size (the smaller the stream, the greater the impact; Minshall et al, 2003), these remote upland ecosystems may be particularly vulnerable to fire-related disturbance.…”