Population dynamics and tolerance to desiccation in a crustacean ostracod adapted to life in small ephemeral water bodies

Abstract

a b s t r a c tGiven their small size, isolation and unpredictability, temporary rockpools present high environmental stress and impoverished communities of species that have adapted to such stressful conditions. Special adaptations of the invertebrates living in these habitats include tolerance to desiccation and fast ontogenetic development in order to maintain stable populations and face high risk of extinction. Dozens of small rockpools (mostly with Ø < 1 m) can be found in east Spain on limestone substrate, where the only known Iberian populations of Heterocypris bosniaca Petkovski et al. (2000), an ostracod species with geographic parthenogenesis, have been recently found. In this survey, two of these rockpools have been monitored during the main hydroperiod between the fall of 2005 and summer 2006 to test the ability of H. bosniaca parthenogenetic populations to face unpredictable hydroperiod dynamics. Pools were visited weekly, and limnological data and ostracod samples were obtained from either water or substrate in dry periods. Ostracod individuals were counted and assigned to growth instars to monitor population changes. In the laboratory, experimental cultures allowed the estimation of survival dependence on the substrate desiccation rate. Throughout the hydrological cycle studied, several hatching periods were observed, usually preceded by desiccation, followed by substrate hydration and water dilution by rain. The demographic changes observed indicate that H. bosniaca populations are able to persist in intermittently inundated environments and produce several generations per annual hydrological cycle. In addition, adult individuals were able to survive in the wet mud of dry pools for longer than five weeks. The experimental data suggest a lower average survival time when exposed to desiccation processes, and that the velocity of substrate water loss is a determining factor for the survival rate of ostracods resisting dry events in temporary ponds. As shown by ostracods' life histories in temporary aquatic environments undergoing unpredictable desiccation events, a combined strategy of adult tolerance to short periods of water scarcity and rapid hatching from resting egg banks can be advantageous for the monopolization of small-sized ephemeral habitats.

Dynamics of ostracod populations from shallow lakes of Patagonia: life history insights

“…It is known that water temperature and conductivity are important factors controlling the development rate of aquatic crustaceans (Roca and Wansard 1997;Aguilar-Alberola and Mesquita-Joanes 2011;Rossi et al 2013). In fact, the estimated development time of C. pubera was clearly dependent on these parameters, being shorter towards the summer, when temperature and conductivity increased.…”

Spatial and environmental effects on a rock‐pool metacommunity depend on landscape setting and dispersal mode

“…Conversely, we found more abundance of rock‐pool specialists in rock pools on the hill (where spatial factors were stronger) than in the ravine (where environmental effects dominated). For example, the ostracod Heterocypris bosniaca and the anostracan species we found, which are considered ephemeral habitat specialists (Aguilar‐Alberola & Mesquita‐Joanes, ; Vanschoenwinkel et al., ), preferred the hillside pools, whereas Heterocypris incongruens , a generalist ostracod (Fryer, ), was abundant in the ravine setting. Therefore, the abundance of specialists with relatively high dispersal abilities may balance the beta diversity, when compared to another setting with generalist communities connected by overflows (or these relative effects may depend on how specialists and generalists are defined).…”

“…61 ha. These rock pools are small temporary waterbodies (ranging from 12 cm to 250 cm at the longest axis), which become filled with rain water (Aguilar‐Alberola & Mesquita‐Joanes, ). We subdivided the study area into two sets: ravine and hillside rock pools (Figure ).…”

La comunidad de ostrácodos en humedales del sudeste de la Península Ibérica

“…Del mismo modo, las especies del género Cypridopsis parecen seleccionar humedales de carácter eminentemente subsalino (lagunas de Prados del Moral y Argamasilla). La falta de una mayor claridad en la ordenación obtenida, podría ser consecuencia tanto de la amplia distribución geográfica de la mayor parte de las especies encontradas, como de la elevada amplitud/tolerancia ecológica que presentan los ostrácodos a diversas variables ambientales, tales como la salinidad (Baltanás et al, 1990;Baltanás, 1992), el hidroperiodo y su la facultad de producir huevos de resistencia (McLay, 1978;Wissinger, 1999;Mesch, 2000;Aguilar-Alberola & Mesquita-Joanes, 2011), el nivel trófico (Danielopol et al, 1993), la temperatura o el sustrato geológico (Benzie, 1989;Casado-Martínez et al, 2016: Li et al, 2021. Los resultados obtenidos confirman que el hidroperiodo, la profundidad, la conductividad y el sustrato geológico determinan en gran medida la presencia de ostrácodos en los humedales del Alto Guadalquivir.…”