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Abstract Ecosystems and their biota operate on cyclic rhythms, often entrained by predictable, small-scale changes in their natural environment. Recording and understanding these rhythms can detangle the effect of human induced shifts in the climate state from natural fluctuations. In this study, we assess long-term patterns of reproductive investment in the Antarctic sea urchin, Sterechinus neumayeri, in relation to changes in the environment to identify drivers of reproductive processes. Polar marine biota are sensitive to small changes in their environment and so serve as a barometer whose responses likely mirror effects that will be seen on a wider global scale in future climate change scenarios. Our results indicate that seasonal reproductive periodicity in the urchin is underpinned by a multiyear trend in reproductive investment beyond and in addition to, the previously reported 18–24 month gametogenic cycle. Our model provides evidence that annual reproductive investment could be regulated by an endogenous rhythm since environmental factors only accounted for a small proportion of the residual variation in gonad index. This research highlights a need for multiyear datasets and the combination of biological time series data with large-scale climate metrics that encapsulate multi-factorial climate state shifts, rather than using single explanatory variables to inform changes in biological processes.

Abstract Climate-related disturbance regimes are changing rapidly with profound consequences for ecosystems. Disturbance is often perceived as detrimental to biodiversity; however, the literature is divided on how they influence each other. Disturbance events in nature are diverse, occurring across numerous interacting trophic levels and multiple spatial and temporal scales, leading to divergence between empirical and theoretical studies. The shallow Antarctic seafloor has one of the largest disturbance gradients on earth, due to iceberg scouring. Scour rates are changing rapidly along the Western Antarctic Peninsula because of climate change and with further changes predicted, the Antarctic benthos will likely undergo dramatic shifts in diversity. We investigated benthic macro and megafaunal richness across 10–100 m depth range, much of which, 40–100 m, has rarely been sampled. Macro and megafauna species richness peaked at 50–60 m depth, a depth dominated by a diverse range of sessile suspension feeders, with an intermediate level of iceberg disturbance. Our results show that a broad range of disturbance values are required to detect the predicted peak in biodiversity that is consistent with the Intermediate Disturbance Hypothesis, suggesting ice scour is key to maintaining high biodiversity in Antarctica’s shallows.

Water scarcity is a major challenge in the Sahel region of West Africa. Water scarcity in combination with prevalent soil degradation has severely reduced the land productivity in the region. The decrease in resiliency of food security systems of marginalized population has huge societal implications which often leads to mass migrations and conflicts. The U.S. Agency for International Development (USAID) and development organizations have made major investments in the Sahel to improve resilience through land rehabilitation activities in recent years. To help restore degraded lands at the farm level, the World Food Programme (WFP) with assistance from USAID's Bureau for Humanitarian Assistance supported the construction of water and soil retention structures called half-moons. The vegetation growing in the half-moons is vitally important to increase agricultural productivity and feed animals, a critical element of sustainable food security in the region. This paper investigates the effectiveness of interventions at 18 WFP sites in southern Niger using vegetative greenness observations from the Landsat 7 satellite. The pre - and post-intervention analysis shows that vegetation greenness after the half-moon intervention was nearly 50% higher than in the pre-intervention years. The vegetation in the intervened area was more than 25% greener than the nearby control area. Together, the results indicate that the half-moons are effective adaptations to the traditional land management systems to increase agricultural production in arid ecosystems, which is evident through improved vegetation conditions in southern Niger. The analysis shows that the improvement brought by the interventions continue to provide the benefits. Continued application of these adaptation techniques on a larger scale will increase agricultural production and build resilience to drought for subsistence farmers in West Africa. Quantifiable increase in efficacy of local-scale land and water management techniques, and the resulting jump in large-scale investments to scale similar efforts will help farmers enhance their resiliency in a sustainable manner will lead to a reduction in food security shortages., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)