Spatial modelling of freshwater fish in semi‐arid river systems: a tool for conservation

Abstract

This paper examines the feasibility of using multivariate statistics to model fish species distribution and habitat requirements for intermittent streams in semi-arid regions, many of which are coming under increasing pressure from water resource development schemes. The assessment was based on the geographical distribution of six endemic fish species in the Guadiana river, a semi-arid river system in southern Iberia. Their presence was related to 20 environmental variables linked to climate, geomorphology, riparian vegetation and location in the drainage basin. These variables were collected in the field or from topographical maps to evaluate habitat suitability and to predict the presence of the species according to season. Multivariate logistic regression in a geographic information system (GIS) environment was performed to identify regions with high probability of occurrence for each species. The variables that best explained the occurrence of the species were the sample location in the drainage basin, the geomorphology and the riparian vegetation. The models presented have a high predictive power and can be used in monitoring and predicting temporal changes caused by human activities. This modelling approach can be used to predict the areas that need to be conserved to protect or rehabilitate the endangered species. Armed with this information, managers can formulate conservation measures to prevent further degradation of the stocks and possibly enhance the populations.

Comparative habitat use by large riverine fishes

“…Understanding habitat patch dynamics (Winemiller et al 2010) can help predict priority areas (Filipe et al 2002) that can cater for multiple species (Welcomme et al 2006). The present study of adults of four large Australian freshwater fishes in the Murray River has provided quantification of their comparative daytime microhabitat use within the same river reach, under the same environmental conditions.…”

“…Globally, lowland riverine fishes face many threats and conservation challenges (Dudgeon et al 2006;Cooke et al 2012), especially in semi-arid systems (Filipe et al 2002) and habitat degradation has contributed to the decline of freshwater fish populations (Cadwallader 1978;Cowx and Welcomme 1998;Cooke et al 2012). The importance of structural habitat for fish has been widely recognised (Matthews 1998) and is a cornerstone central to the management of fishes (Rice 2005), especially keystone species (Naiman and Latterell 2005).…”

“…Protecting and rehabilitating habitats is hence critical for conservation management and threatened-species recovery (Freeman and Freeman 1994;Peterson and Rabeni 2001) and this involves understanding the habitat needs of fish species (Rice 2005;Rosenfeld and Hatfield 2006). Detailed habitat requirements of species can be used to develop models to predict priority areas for their conservation or rehabilitation (Filipe et al 2002). Because habitat patches occur at differing scales, understanding fish-habitat patch relationships is essential (Wiens 2002), as2004; Koehn and Lintermans 2012).…”

High Variability Is a Defining Component of Mediterranean-Climate Rivers and Their Biota

“…These shifts occur both at the reach scale [86,87] and the microhabitat scale [88,89]. In contrast, the few studies that have explored variation in fish assemblages across seasons found no significant differences in diversity [86] or fish assemblage structure [90], despite considerable variation in environmental conditions among seasons.…”

Estado de las poblaciones de trucha en los ríos de la Comunidad Valenciana y caracterización de sus hábitats

“…En este sentido, también se han desarrollado estudios en la Península Ibérica a nivel de cuenca y microhábitat, donde se indagan sobre las particularidades que sufren las especies que viven en ríos influenciados por el clima mediterráneo, donde los fuertes periodos de lluvias torrenciales y sequías y la alta variación intra-anual e inter-anual de sus caudales es una constante . Ejemplos a nivel de cuenca o segmentos fluviales lo encontramos en ríos portugueses (Godinho et al, 2000;Filipe et al, 2002;Magalhães et al, 2002) y más recientemente a nivel de microhábitat en ríos centrales españoles (Ayllón et al, 2009;Martínez-Capel et al, 2009), pero sorprende el hecho de que no se ha realizado ningún estudio sobre la influencia de los hábitats en las abundancias de peces en ríos mediterráneos. Hankin (1984) recomendaba que las secciones de muestreo del hábitat se realizaran de forma equivalente e independientemente en estratos construidos a partir de los distintos tipos naturales de los hábitats de un río dentro de cada cuenca, para cometer menor error en la estimación del número de salmones.…”