Egg production and life history of Alona guttata Sars, 1862 (Cladocera, Chydoridae): implications for colonization of temporary ponds

Cladocerans are a diverse group of species that show rapid responses to changes in environmental conditions. This adaptive capacity has important implications for egg production and life cycle, especially in transitory environments such as temporary waterbodies. The present study investigated the life history and egg production of Alona gutatta Sars, 1862 (Crustacea, Cladocera), an abundant and frequent species from a high-altitude temporary pond (Lagoa Seca, Minas Gerais, Brazil). Newly hatched neonates were monitored in relation to time of maturation, number of eggs produced per female and time of survival. Neonates required a mean of 8 days to mature. A. guttata survived for a mean of 30.9 ± 8.1 days and produced 2 eggs per brood, generating a mean of 10.95 ± 6.41 neonates during the entire life cycle. The rapid development, short time to produce eggs and long life cycle are important adaptations to the adverse environmental conditions of temporary aquatic environments, which can contribute to the rapid colonization of Alona guttata in transitory ecosystems.

Phenotypic Plasticity and Parental Effect on Rearing of Two Diverse Habitat Environment for Laboratory Reared Sympetrum Meridionale

Laboratory observations on rearing experiment of Odonata serve to answer many evolutionary and ecological questions. In order to evidences the role of species parental habitat provenience in the development behaviour of their offspring, we surveyed several life history traits of two rearing populations of Sympetrum meridionale (Anisoptera: Sympetrinae), coming from two different habitats across north-eastern Algeria. The first one is a RAMSAR wetland called ‘Mekhada’ (a perennial water body), and the second one is a temporary pond located at “Maouna” Mountain (1400 m altitude). Overall, the development patterns of the two populations of dragonflies vary with the type of habitat the parental generation of the species occupy (Factorial ANCOVA: all p < 0.05). Firstly, egg mortality was very low in dragonfly population inhabiting the RAMSAR wetland compared of those belonging to Maouna Mountain. Secondly new-borne larvae stemming from females inhabiting the Mekhada wetland develop more slowly than did those coming from the “Maouna” Mountain pond. Finally, larvae of Sympetrum meridionale stemming from females inhabiting the temporary wetland were heavier than those inhabiting the perennial wetland. Such studies will ads considerably to our understanding of the mechanisms that are responsible for possible effects of environmental changes on life history traits of dragonflies across the southern part of their distribution range.

Mediterranean Temporary Ponds: using isotope hydrology tools to describe and understand their behaviour

&lt;p&gt;Mediterranean temporary ponds are very shallow ponds, isolated from permanent water bodies, which undergo a periodic cycle of flooding and drought, and have a characteristic flora and fauna adapted to this alternation. This habitat is mainly distributed in dry and sub-arid areas. Mediterranean temporary ponds are identified as one of the worldwide biodiversity hotspots and constitutes therefore a priority habitats according to the Natura 2000 network of the European Union (3170*, Council Directive 92/43/CEE). The development of flora and fauna in this type of ecosystem is defined by the natural length of the hydro-period. However, little is known about the hydrological functioning of these very specific hydrosystems. DespiteHS10 this protective conservation status, this habitat has suffered continuous degradation and loss disappearing at a fast rate due anthropogenic impacts and climate pressures. In most cases, temporary wetland disappearance is unintentional and related to a lack of understanding of its hydrological functioning within the watershed.&lt;/p&gt;&lt;p&gt;The aim of this work is, hence, to use the tools of the isotope hydrology to increase our basic understanding of the hydrological functioning of the Mediterranean temporary ponds. Our study focuses on the Musella temporary pond located in Southern Corsica (France) which undergoes important man-induced and climatic pressures. During one full hydrological cycle, surface and groundwater levels, major ions, stable isotopes of the water molecules as well as field parameters (temperature, pH, electrical conductivity, dissolved oxygen) have been measured every month.&lt;/p&gt;&lt;p&gt;Results bring information on the water quality, chemical stability and temporal evolution in terms of surface water level as well as potential connection with the underlying carbonated aquifer. The stable isotopes inform about the origin of water, its mixing processes with groundwater, and its evaporative status through time.&lt;/p&gt;&lt;p&gt;Flooding and drying processes of the Musella temporary pond are now better constrained and documented projections can now be set up towards the resilience of the hydrosystem considering the future consequences of climate change in the Mediterranean region.&lt;/p&gt;

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

&lt;p&gt;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&amp;#176;C, preventing the collection of terrestrial data, particularly within the tropics.&lt;/p&gt;&lt;p&gt;Here we propose an alternative low-cost method for the determination of a temporary pond&amp;#8217;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.&lt;/p&gt;&lt;p&gt;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.&lt;/p&gt;

First record of Scapholeberis freyi Dumont and Pensaert, 1983 (Crustacea:Anomopoda: Daphniidae) from Colombia

From the analysis of plankton samples from a temporary pond of northern Colombia some female specimen of the daphinid cladoceran Scapholeberis freyi Dumont and Pensaert, 1983 was collected. It represents the first report in Colombia and expands its known occurrence in South America. The specimens observed are described and compared with available morphological data of their closest congeners. A brief descriptions of this taxon based on Colombian material is given.

Impacts of agrochemical intensification on the assembly and reassembly of a mainland-island model metacommunity

ABSTRACTMany lentic aquatic environments are found embedded in agricultural fields, forming complex metacommunity structures. These habitats are vulnerable to contamination by agrochemicals, which can differentially affect local communities depending on the intensity and variability of species dispersal rates. We conducted a field experiment to assess how agrochemical intensification simulating the conversion of savannas into managed pastures and sugarcane fields affects freshwater community structure at different levels of spatial isolation. We constructed forty-five 1,200-L artificial ponds in a savanna landscape at three distances from a source wetland (30 m, 120 m, and 480 m). Ponds were spontaneously colonized by aquatic insects and amphibians and treated with no agrochemicals (‘savanna’ treatment), fertilizers (‘pasture’ treatment), or fertilizers and a single pulse of the insecticide fipronil and the herbicide 2,4-D (‘sugar cane’ treatment) following realistic dosages and application schedules. The experiment encompassed the entire rainy season. ‘Pasture’ communities were only slightly different from controls largely because two predatory insect taxa were more abundant in ‘pasture’ ponds. ‘Sugarcane’ communities strongly diverged from other treatments after the insecticide application, when a decrease in insect abundance indirectly benefitted amphibian populations. However, this effect had nearly disappeared by the end of the rainy season. The herbicide pulse had no effect on community structure. Spatial isolation changed community structure by increasing the abundance of non-predatory insects. However, it did not affect all predatory insects nor, surprisingly, amphibians. Therefore, spatial isolation did not change the effects of agrochemicals on community structure. Because agrochemical application frequently overlaps with the rainy season in many monocultures, it can strongly affect temporary pond communities. Ponds embedded in pastures might suffer mild consequences of fertilization by favoring the abundance of few predators through bottom-up effects. Ponds in sugarcane fields, however, might experience a decline in the insect population, followed by an increase in the abundance of amphibians tolerant to environmental degradation. Furthermore, we found no evidence that isolation by distance can change the general effects of chemical intensification, but future experiments should consider using real crop fields as the terrestrial matrix since they can represent different dispersal barriers.