Pigment allocation to eggs decreases plasma antioxidants in a songbird

Although evidence is accumulating on the adaptive function of female ornamentation, very little is known about maternal allocation decisions involving sexual signaling and other reproductive functions. Blue egg coloration has been suggested as a sexually selected signal of female quality to males, and some recent studies are in accordance with this hypothesis. Blue eggshell coloration results from the deposition of biliverdin pigment by laying females, which is a potent antioxidant. Thus, egg pigmentation should be costly in terms of antioxidants, an assumption of the signaling hypothesis that has not been tested yet. We induced increased reproductive effort in a set of female pied flycatchers Ficedula hypoleuca through nest removal and measured egg pigmentation and plasma antioxidant levels in relation with a control group. Experimental females showed a negative association between egg color and plasma antioxidant levels, while there was no relationship for control birds. This supports that egg pigmentation is costly in terms of general antioxidant defenses and suggests a tradeoff between the allocations to both traits. Furthermore, experimental females with more colorful eggs raised more fledglings, especially when breeding early. Controls did not show a relationship between egg color and reproductive success. Females laying more colorful eggs could have shifted their allocation decisions towards current reproduction, at the expense of their own antioxidant defenses. Our results highlight that blue egg coloration is a life-history trait, subject to tradeoffs with other attributes, and seems to be especially informative under harsh breeding conditions.     

Daphnia emergence: a sensitive indicator of fire-retardant stress in temporary wetlands

Fire-retardant formulations are increasingly used by fire managers to control wildland fires. Their extensive use requires an assessment of their impacts in those ecosystems that could be affected by them. Recent studies indicate the potential for environmental impacts when accidentally delivered to surface waters. Yet the response of temporary wetlands, such as vernal pools, typical in Mediterranean areas, is unknown. This study reports on the emergence response of a wetland population of Daphnia curvirostris Eylmann (Cladocera, Crustacea) from sediments that were treated with a commercial fire retardant (Fire-Trol 934). Three application levels were used: 1, 3 and 5 L m(-2). The low and medium levels are in the range of manufacturer's recommendations of use in the field based on the fuel characteristics. The high level simulates local elevated concentrations that may result from inhomogeneous retardant delivery. Results indicate that emergence success decreases with increasing application rate, leading to a complete failure with application levels of 5 L m(-2). This suggests that benthic-pelagic interactions in temporary wetlands-often the primary way by which recolonization of isolated wetlands occurs-can be significantly impacted by fire retardants once they fill with fall/winter rains, thereby serving as a sensitive indicator of fire-retardant contamination. Results highlight a research need for establishing of criteria for effective, but environmentally safe use of fire retardants in the environment.     

Isotopic composition and origin of uranium and plutonium in selected soil samples collected in Kosovo

Soil samples collected from locations in Kosovo where depleted uranium (DU) ammunition was expended during the 1999 Balkan conflict were analysed for uranium and plutonium isotopes content (234U, 235U, 236U, 238U, 238Pu, (239 + 240)Pu). The analyses were conducted using gamma spectrometry (235U, 238U), alpha spectrometry (238Pu, (239 + 240)Pu), inductively coupled plasma-mass spectrometry (ICP-MS) (234U, 235U, 236U, 238U) and accelerator mass spectrometry (AMS) (236U)). The results indicated that whenever the U concentration exceeded the normal environmental values (approximately 2 to 3 mg/kg) the increase was due to DU contamination. 236U was also present in the released DU at a constant ratio of 236U (mg/kg)/238U (mg/kg) = 2.6 x 10(-5), indicating that the DU used in the ammunition was from a batch that had been irradiated and then reprocessed. The plutonium concentration in the soil (undisturbed) was about 1 Bq/kg and, on the basis of the measured 238Pu/(239 + 240)Pu, could be entirely attributed to the fallout of the nuclear weapon tests of the 1960s (no appreciable contribution from DU).     

A stakeholder driven process to reduce vulnerability to climate change in Hermosillo,Sonora, Mexico

While there is a growing body of knowledge on potential impacts of climate change on water availability, there has been much less empirical research on exploring the viability of particular adaptation options. The participation of stakeholders in defining appropriate adaptation strategies is increasingly recognized as a critical element in the translation of climate change impact research into effective actions to reduce future vulnerability, yet the process by which stakeholders are included in such initiatives is not well-defined. This article presents the results of a pilot project in which a participatory approach was employed to identify and evaluate adaptation options to climate change scenarios for Sonora’s capital city, Hermosillo. In an iterative process, stakeholders representing different water users and managers in the city met to discuss climate change scenarios, identify specific adaptation options, and evaluate a subset of options for possible future implementation. This process enabled the focus of the investigation on those adaptations that addressed not only concerns with the potential future impacts of climate change but also the immediate and pressing concerns about development patterns and water use in the city. Two of the adaptations to climate change identified by stakeholders would also reduce energy demand. The simplicity of the approach makes it a feasible model for adaptation initiatives in other regions of Mexico and in other countries in Latin America.