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Argentine ants harm nestlings of the blue tit

The consequences of ant invasions on ecosystems may only become apparent after long periods. In addition, predicting how sensitive native fauna will respond is only possible if the underlying proximate mechanisms of their impact are identified. The attraction of the native and invasive ant community to artificial bird nests was studied, together with reproduction of a wild native songbird over five consecutive breeding seasons in relation to the presence of an invasive ant species. Biometric, reproductive and individual blood parameters of great tits Parus major breeding in invaded as compared to uninvaded sites by Argentine ants Linepithema humile were analysed. Great tits bred preferably in uninvaded territories by the Argentine ant. Moreover, Argentine ants were more abundant at nests in invaded sites, than any native ant species were at uninvaded sites. Further, Argentine ants recruited at the artificial nests more intensively and responded to a larger variety of nest (intact eggs, cracked eggs, faeces, and cracked eggs plus faeces) contents than native species. Although breeding success and adult condition did not vary in relation to invasion status, offspring quality was negatively affected by the presence of Argentine ants. Nestlings reared in invaded sites were lighter, with lower wing/tarsus length ratio and had a reduced nutritional condition and altered oxidative stress balance as measured from several blood parameters. The interspersed distribution and small distance between invaded versus uninvaded territories suggest that ant presence affects nestling condition through direct interference at the nest. These results highlight the importance of evaluating the proximate effects like physiological parameters of the native fauna, when studying invasive ant-native bird interactions. informacion[at] Álvarez et al (2020) Breeding consequences for a songbird nesting in Argentine ant' invaded land. Biol Invasions
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Identifying the most threatened areas by human activity in the Mediterranean Sea

Identifying the most threatened areas by human activity in the Mediterranean Sea

A study analysed and distributed the existing information on several impacts that are simultaneously affecting the Mediterranean Sea: from climate impacts like the rise of temperatures in the sea, to the fishing pressure on natural resources or changes in physical and chemical conditions. The result is a map of the places that are most affected by human activity such as the Adriatic Sea, the Aegean Sea, the African coast and the Catalan sea, among others. According to the researchers, this information will enable identifying areas that need local action to minimize the impacts of a global problem such as climate change. The study is framed within the concept of Safe Operating Spaces (SOS), which determines a multidimensional space in which we would find an ecosystem and is delimited by several kinds of impacts such as pollution, fishing, or the temperature of water. In order for this ecosystem to be in the right conditions, magnitude of the impacts should not exceed certain thresholds, therefore, if the magnitude of an impact increases, the thresholds of the others decrease and vice-versa. By delimiting a SOS out of climate and human impacts, when reducing anthropic pressure, the threshold for climate impacts would increase and therefore, the ecosystem's ability to resist environmental impacts related to climate change would increase. To spatially delimit the potential impacts that would affect the Mediterranean Sea, several methodologies and databases such as the largest temporary series of remote sensing –satellite images- that provide data on the temperature of the marine surface were combined. Data on the distribution of the fishing pressure provided by Global Fishing Watch were also used. According to the study, those areas that are affected by human impact would be more potentially vulnerable to climate change. In particular, the results show that there are certain areas that are more vulnerable such as the Adriatic Sea, the Aegean Sea, the African coast and the Catalan sea, where fishing intensity is high. If we add the rise of temperatures in the sea, caused by global warming, the result is that there will be species of commercial interest like the sardine, which will be particularly affected, since they are very sensitive to the rise of temperatures. Knowing how to distribute these threats can help management of several activities like fishing. For instance, it can regulate these activities in affected areas or move fishing to areas that are less affected by other threats. Local administrations cannot fight climate change by themselves, since it requires the consensus and action of all the international community. However, working on other local impacts, the "vulnerability" of certain areas and ecosystems regarding the climate change could be reduced. In addition to fighting global warming, potential measures of mitigation could consist in managing local impacts. informacion[at] Ramírez et al (2018) Spatial congruence between multiple stressors in the Mediterranean Sea may reduce its resilience to climate impacts. Scientific Reports 8:14871 DOI 10.1038/s41598-018-33237-w