The use of environmental data in detailing the hydroregime of a temporary pond

<p>Temporary waters span both terrestrial and aquatic environments, though the terrestrial phase is typically understudied. A key component in the ecology of these water bodies is the length of the hydroperiod. To date, hydroperiod length in temporary waters is determined largely by site visits and camera traps. These methods of determination however, are taxing on resources at fine temporal resolutions (daily). While water level loggers are able to determine hydroperiod length, they are relatively expensive and peak at 50°C, preventing the collection of terrestrial data, particularly within the tropics.</p><p>Here we propose an alternative low-cost method for the determination of a temporary pond’s hydroperiod length using anchored HOBO pendant dataloggers of temperature and light intensity. By analysing the environmental data collected at fine temporal resolution across dry and wet seasons - corroborated by daily rainfall collection and frequent site visits - the determination of phase, whether aquatic or terrestrial, using this method was possible. This then extended to the determination of the length of the hydroperiod.</p><p>In addition to determining hydroperiod length, this method also provided data on the diurnal temperature dynamics, photoperiod and irradiation intensity of the aquatic and terrestrial phases. Trends in pond drying were also detectable using these data. In the terrestrial phase, the method provided data on soil surface temperatures, which was particularly lacking for the Caribbean. These data are important in understanding environmental stress regimes among aquatic and terrestrial ecosystems, with applications in agriculture, conservation and infrastructure.</p>

Key environmental factors for the conservation of large branchiopods in farmland vernal pools — a case from a Central European diversity hotspot

Large branchiopod crustaceans are among the most threatened freshwater invertebrates of the world. They are regarded as a flagship group in the conservation of temporary waters, and knowledge of their ecology and conservation has developed rapidly in recent years, especially in the Mediterranean region. Little is known, however, about population functioning in species associated with vernal pools in cooler temperate areas, despite recent data showing a significant decline in their localities. The present study was conducted in western Poland, on a cluster of vernal pools known to host a Central European diversity hotspot of large branchiopods. We collected data on water and sediment quality, as well as hydroperiod length, to determine their effect on the occurrence of four large branchiopod species present in the ponds during our samplings: Eubranchipus grubii (Anostraca), Lynceus brachyurus (Laevicaudata), Cyzicus tetracerus (Spinicaudata) and Lepidurus apus (Notostraca). According to the statistical analyses, the presence or absence of particular species was affected by hydroperiod length, heavy metal content in the sediments of the marginal zone of the pond, total water phosphorus content, and pH value. Since previous studies show that deep and relatively small kettle-hole ponds seem to be the most vulnerable to human-induced changes in water nutrient contents and acidification, large branchiopod populations of this type of pools should be the first target for monitoring and active forms of protection, with the aim of maintaining the good water quality. Shallow shore-bursting type ponds are subject to increased heavy metal contamination and require activities reducing the influx of these elements from their agricultural catchment. Possible forms of protection are suggested, and the use of large branchiopods as an umbrella group in temporary waters of temperate climate is also discussed.