No abstract

The Bakonjo have long practiced an agroforestry system of cultivation on the Ugandan slopes of the Rwenzori Mountain range. All terrain above 1600–2200 m has been strictly protected for many years because it is part of a national park. As a trade-off, the landscapes outside the park have been largely deforested. In the meantime, tourist numbers have increased. In Ruboni, a village of 1200 people, the closest to the eastern gate of the park, we interviewed a random sample of 51 residents aged >14 to understand how they perceived the landscape, park and tourism. Cultivated features were not essential to describe the place of residence, in contrast to natural features and human engineered devices. Cultivated and natural elements were judged as beautiful. Even if the inhabitants did not like human engineered facilities, they welcomed their improvement. The origin of native and non-native plants was not consistently recognized. These results show that the inhabitants feel affection for the agroforestry pattern of the Rwenzori landscape. However, ecological, social and economic pressures are challenging land use sustainability. This would be better addressed by an integrated pattern of land governance than the current two models: strict protection inside the park and relaxed land use outside.

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Artificial light at night (ALAN) is a globally spreading anthropogenic stressor, affecting more than 20% of coastal habitats. The alteration of the natural light/darkness cycle is expected to impact the physiology of organisms by acting on the complex circuits termed as circadian rhythms. Our understanding of the impact of ALAN on marine organisms is lagging behind that of terrestrial ones, and effects on marine primary producers are almost unexplored. Here, we investigated the molecular and physiological response of the Mediterranean seagrass, Posidonia oceanica (L.) Delile, as model to evaluate the effect of ALAN on seagrass populations established in shallow waters, by taking advantage of a decreasing gradient of dim nocturnal light intensity (from < 0.01 to 4 lx) along the NW Mediterranean coastline. We first monitored the fluctuations of putative circadian-clock genes over a period of 24 h along the ALAN gradient. We then investigated whether key physiological processes, known to be synchronized with day length by the circadian rhythm, were also affected by ALAN. ALAN influenced the light signalling at dusk/night in P. oceanica, including that of shorter blue wavelengths, through the ELF3–LUX1–ZTL regulatory network, and suggested that the daily perturbation of internal clock orthologs in seagrass might have caused the recruitment of PoSEND33 and PoPSBS genes to mitigate the repercussions of a nocturnal stress on photosynthesis during the day. A long-lasting impairment of gene fluctuations in sites characterised by ALAN could explain the reduced growth of the seagrass leaves when these were transferred into controlled conditions and without lighting during the night. Our results highlight the potential contribution of ALAN to the global loss of seagrass meadows, posing questions about key interactions with a variety of other human-related stressors in urban areas, in order to develop more efficient strategies to globally preserve these coastal foundation species.