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Simple Summary: There is increasing interest in the study of how the ongoing climate change is affecting insect populations. However, most research has been focused on a limited number of groups that are particularly charismatic or expected to respond more clearly to climate change. Moreover, most research has been developed in a few areas (especially northern and central European countries), while others (such as the Mediterranean basin) have been largely overlooked. Therefore, more empirical research is needed, particularly on less charismatic species, groups that are expected to react less dramatically to climatic change, and key areas that are still poorly investigated. This study investigates changes in distributional and activity patterns in a common, ecologically tolerant, forest tenebrionid beetle in a region (central Italy) within the Mediterranean biodiversity hotspot, an area strongly subjected to the ongoing climate change, but for which research is still limited. By analyzing changes in elevation, latitude, longitude, and seasonal activity between 1900–1980 and 1981–2022, the results provided insights into the potential effects of climate change on this species. The beetle's average values of elevation and latitude were found to have been increased in the second period. In response to rising temperatures, the species became more frequent at higher elevation and in northern places. No strong evidence was found for an earlier species seasonal activity, but this could be due to the inclusion in the analysis of likely overwintering individuals. The findings suggest that even thermally tolerant species can undergo distributional shifts in elevation and latitude, even at a relatively small scale. There is an increasing volume of literature on the impact of climate change on insects. However, there is an urgent need for more empirical research on underrepresented groups in key areas, including species for which the effects of climatic change may seem less evident. The present paper illustrates the results of a study on a common forest tenebrionid beetle, Accanthopus velikensis (Piller and Mitterpacher, 1783), at a regional scale within the Mediterranean basin. Using a large set of records from Latium (central Italy), changes in the median values of elevation, latitude, longitude, and phenology between two periods (1900–1980 vs. 1981–2022) were tested. Records of A. velikensis in the period 1981–2022 showed median values of elevation and latitude higher than those recorded in the first period. Thus, in response to rising temperatures, the species became more frequent at higher elevation and in northern places. By contrast, A. velikensis does not seem to have changed its activity pattern in response to increased temperatures, but this might be an artifact due to the inclusion of likely overwintering individuals. The results obtained for A. velikensis indicate that even thermally euryoecious species can show changes in their elevational and latitudinal distribution, and that poleward shifts can be apparent even within a small latitudinal gradient. [ABSTRACT FROM AUTHOR]

During the Messinian, the sensitivity of the Mediterranean Basin to ecosystem perturbation was enhanced in response to the progressive restriction of water exchange with the Atlantic Ocean. The widespread deposition of organic-rich layers (i.e. sapropel) during the Messinian testifies the perturbation of the carbon and oxygen cycles; indeed, these sediments were deposited under conditions of oxygen starvation, presumably in response to a periodic deterioration of the thermohaline circulation strength. Disentangling the causes, the effect and magnitude of the thermohaline circulation weakening during the geological past is crucial for better constraining present and near-future deoxygenation dynamics in the Mediterranean region under the current climate warming. For this purpose, we investigate a Messinian sapropel-bearing succession cropping out at Monte dei Corvi (Ancona, central Italy) with mineralogical, petrographic, micropaleontological and stable Carbon and Oxygen isotopic analyses. We show that sapropel layers were deposited in response to an increase of the sea surface buoyancy, which hampered the thermohaline circulation and thus the oxygenation of bottom water, in turn affecting the bioturbating organisms. Within the lithological cycle, the recovery of an efficient thermohaline circulation is recorded by thin packstone layers underlying the marly limestone/marlstone, which record intense bottom currents. The marly limestone/marlstone accumulated during periods of intense primary productivity and organic carbon export to the sea bottom, which promoted bottom hypoxia but not organic matter preservation. We infer that these lithological changes resulted from variations in the Adriatic Deep Water formation system, controlled by precession-driven climatic and oceanographic changes. By integrating previously published Sea Surface Temperature (SST) with new isotopic and mineralogical data, we show that variations in Sea Surface Salinity (SSS) were the leading factor controlling sapropel deposition, minimizing the role of primary productivity. The SSTs characterizing the sapropel deposits are close to the range of those projected in the Eastern Mediterranean at the end of this century under climate warming. In this scenario, future warming will be coupled with SSS increase, which will counteract the density loss provided by temperature, making the bottom deoxygenation in the Eastern Mediterranean abysses unlikely. However, additional forcing, such as winter heat waves and eutrophication, could contribute to negatively affecting the Mediterranean oxygen balance and should be considered in model-based projections. • The Monte dei Corvi recorded the changes in the ADW formation during the Messinian. • The bottom deoxygenation resulted from variations in the freshwater input. • Future deoxygenation in Mediterranean can be provided by productivity or heatwaves. [ABSTRACT FROM AUTHOR]