Phylogenomic and population genomic analyses reveal the spatial-temporal dynamics of diversification of the Nigella arvensis complex (Ranunculaceae) in the Aegean archipelago

The continental-shelf islands of the Aegean Sea provide an ideal geographical setting for evolutionary-biogeographical studies but disentangling the relationships between palaeogeographical history and the times, orders of modes of taxon divergence is not straightforward. Here, we used phylogenomic and population genomic approaches, based on orthologous gene sequences and transcriptome-derived SNP data, to reconstruct the spatial-temporal evolution of the Aegean Nigella arvensis complex (Ranunculaceae; 11 out of 12 taxa). The group's early diversification in the Early/Mid-Pliocene (c. 3.77 Mya) resulted in three main lineages (Greek mainland vs. central Aegean + Turkish mainland/eastern Aegean islands), while all extant taxa are of Late Plio-/Early Pleistocene origin (c. 3.30-1.59 Mya). Demographic modelling of the outcrossing taxa uncovered disparate modes of (sub)speciation, including divergence with gene flow on the Greek mainland, para- or peripatric diversification across eastern Aegean islands, and a 'mixing-isolation-mixing (MIM)' mode of subspeciation in the Cyclades. The two selfing species (N. stricta, N. doerfleri) evolved independently from the outcrossers. Present-day island configurations are clearly insufficient to explain the spatial-temporal history of lineage diversification and modes of (sub)speciation in Aegean Nigella. Moreover, our identification of positively selected genes in almost all taxa calls into question that this plant group represents a case of 'non-adaptive' radiation. Our study revealed an episodic diversification history of the N. arvensis complex, giving new insight into the modes and drivers of island speciation and adaption across multiple spatiotemporal scales.

Spatial-temporal and structural differences in the carbon footprints embedded in households food waste in urban and rural China

Household food waste (HFW) accounted for about 66% of global food waste's total carbon footprints (CF). Based on China's macro-panel food consumption data, this paper measures the urban-rural and provincial differences in the HFW CF from scale, structure, and temporal-spatial evolution perspectives. The results indicate that HFW and CF continue to grow, and the total CF and per capita HFW in urban households are higher than in rural households. The structural differences between urban and rural HFW CF vary significantly over time and spaces, which reflected that rural households in the southeastern coastal areas have higher per capita HFW CF than urban in 2019. The research results help to clarify the distribution and evolution pattern of HFW CF in China and offer new ideas for the differentiated governance of CF reduction in the food system.

Indicators for Evaluating High-Quality Agricultural Development: Empirical Study from Yangtze River Economic Belt, China

Agriculture is the foundation of the national economy, and achieving high-quality agricultural development is an important support for strong economic development in the post-pandemic era. Based on the new development philosophy of the Chinese government, this study constructs an evaluation framework of "innovation-coordination-green-openness-sharing" for high-quality agricultural development, and quantitatively assesses the level of high-quality agricultural development in China's Yangtze River Economic Belt with a systematic integration model, and explores the spatial evolution characteristics and obstacles of the level of high-quality agricultural development in Yangtze River Economic Belt. It reveals that the level of high-quality agricultural development in the Yangtze River Economic Belt shows a fluctuating upward trend in general, but there is variability among regions. The green dimension has the fastest development rate, followed by innovation and sharing. In terms of spatial characteristics, it gradually shows a pattern dominated by high levels and shows the characteristics of agglomeration, but the spatial correlation is not high. In terms of obstacle factors, openness and coordination are the main obstacle factors. Considering the different agricultural development models, it is suggested that international cooperation, new agricultural cooperation, and differentiated policies can be considered to promote high-quality agricultural development. This study provides a more complete evaluation framework for government policy-making authorities to measure the level of regional agricultural development and help regional agriculture achieve sustainable development at a higher quality level.

Exploring the convergence patterns of PM2.5 in Chinese cities

Economic development and ongoing urbanization are usually accompanied by severe haze pollution. Revealing the spatial and temporal evolution of haze pollution can provide a powerful tool for formulating sustainable development policies. Previous studies mostly discuss the differences in the level of PM2.5 among regions, but have paid little attention to the change rules of such differences and their clustering patterns over long periods. Therefore, from the perspective of club convergence, this study employs the log t regression test and club clustering algorithm proposed by Phillips and Sul (Econometrica 75(6):1771-1855, 2007. 10.1111/j.1468-0262.2007.00811.x) to empirically examine the convergence characteristics of PM2.5 concentrations in Chinese cities from 1998 to 2016. This study found that there was no evidence of full panel convergence, but supported one divergent group and eleven convergence clubs with large differences in mean PM2.5 concentrations and growth rates. The geographical distribution of these clubs showed significant spatial dependence. In addition, certain meteorological and socio-economic factors predominantly determined the convergence club for each city.