Regionally nested patterns of fish assemblages in floodplain lakes of the Magdalena river (Colombia)

Abstract

We investigated if fish assemblages in neotropical floodplain lakes (cienagas) exhibit nestedness, and thus offer support to the managers of natural resources of the area for their decision making. The location was floodplain lakes of the middle section of the Magdalena river, Colombia. We applied the nested subset analysis for the series of 30 cienagas (27 connected to the main river and three isolated). All fish were identified taxonomically in the field and the matrix for presence–absence in all the lakes was used for the study of the pattern of nestedness. The most diverse order was Characiformes (20 species), followed by Siluriformes (19 species). Characidae and Loricaridae were the richest families. The species found in all the lakes studied were migratory species (17), and sedentary species (33). Two species (Caquetaia kraussii and Cyphocharax magdalenae) were widespread across the cienagas archipelago (100% of incidence). Nestedness analysis showed that the distribution of species over the spatial gradient studied (840 km) is significantly nested. The cienagas deemed the most hospitable were Simiti, El Llanito, and Canaletal. Roughly, 13 out of the 50 species caught show markedly idiosyncratic distributions. The resulting dataset showed a strong pattern of nestedness in the distribution of Magdalenese fishes, and differed significantly from random species assemblages. Out of all the measurements taken in the cienagas, only the size (area) and local richness are significantly related to the range of order of nested subset patterns (r=–0.59 and –0.90, respectively, at p < 0.01). Differential species extinction is suggested as the cause of a nested species assemblage, when the reorganized matrix of species occurring in habitat islands is correlated with the island area. Our results are consistent with this hypothesis.

Diel cycle size-dependent trophic structure of neotropical fishes: a three year case analysis from 35 floodplain lakes in Colombia

“…Granado‐Lorencio et al. (,b) provided physical and chemical details of the selected lakes (see Appendix ). Each lake was sampled over the course of 24 h during one rainy season.…”

Freshwater fish faunas, habitats and conservation challenges in the Caribbean river basins of north‐western South America

“…These data were published by Granado‐Lorencio et al . (2012 a , b ), Hernández‐Serna et al . (), Jiménez‐Segura et al .…”

“…These aquatic systems have received much of the scientific research attention because they are important for fisheries sustainability in the Magdalena‐Cauca Basin (Arango‐Rojas et al ., ; Jaramillo‐Villa & Jiménez‐Segura, ; Ríos‐Pulgarín et al ., ; Jiménez‐Segura et al ., ; Granado‐Lorencio et al ., 2012 a , b ). Climatic seasonality determines the characteristics of the lakes and the behaviour of the fish fauna is also synchronized with it.…”

A Systematic, Automated Approach for River Segmentation Tested on the Magdalena River (Colombia) and the Baker River (Chile)

“…(k) Rio Cesar, Cauca, and S. Jorge (reach T10, 9, 8, 7, 6, 5, 4): the influence of the important Cesar River is significantly moderated by the large wetland (the "Ciénaga La Zapatosa") at its outlet into the Magdalena River. This wetland, analogously to many other wetlands in the area, regulates the river-wetland water exchanges in both senses with a strong effect on the dynamics of the fish population (Granado-Lorencio et al [41]; López-Casas S. et al [42]). In the whole area, the Magdalena maintains its anastomosing character until the exit from the Mojana region (reach T4), with several character variations of the main stem (see "brazo La Loba") and additional branches.…”