陕西神木侏罗纪恐龙足迹的新发现及其地层学意义

在进行文物普查时于陕西神木县栏杆堡镇附近发现了大量恐龙足迹化石,而且足迹的种类也不尽相同,同以往该地发现的足迹类型相比、存在明显的区别。两处足迹化石点地层时代分属早侏罗世和中侏罗世,较之以前在该地和省内其他地方发现的足迹化石的时代要早很多。在对化石所在地层作对比的同时,对陕西神木的恐龙足迹化石分布展开了探讨。     

Agricultural and forestry trade drives large share of tropical deforestation emissions

Deforestation, the second largest source of anthropogenic greenhouse gas emissions, is largely driven by expanding forestry and agriculture. However, despite agricultural expansion being increasingly driven by foreign demand, the links between deforestation and foreign demand for agricultural commodities have only been partially mapped. Here we present a pan-tropical quantification of carbon emissions from deforestation associated with the expansion of agriculture and forest plantations, and trace embodied emissions through global supply chains to consumers. We find that in the period 2010–2014, expansion of agriculture and tree plantations into forests across the tropics was associated with net emissions of approximately 2.6 gigatonnes carbon dioxide per year. Cattle and oilseed products account for over half of these emissions. Europe and China are major importers, and for many developed countries, deforestation emissions embodied in imports rival or exceed emissions from domestic agriculture. Depending on the trade model used, 29–39% of deforestation-related emissions were driven by international trade. This is substantially higher than the share of fossil carbon emissions embodied in trade, indicating that efforts to reduce greenhouse gas emissions from land-use change need to consider the role of international demand in driving deforestation. Additionally, we find that deforestation emissions are similar to, or larger than, other emissions in the carbon footprint of key forest-risk commodities. Similarly, deforestation emissions constitute a substantial share (˜15%) of the total carbon footprint of food consumption in EU countries. This highlights the need for consumption-based accounts to include emissions from deforestation, and for the implementation of policy measures that cross these international supply-chains if deforestation emissions are to be effectively reduced.     

Identifying regional drivers of future land-based biodiversity footprints

Biodiversity footprints quantify the impacts on ecosystems caused by final consumption in a region, accounting for imports and exports. Up to now, footprint analyses have typically been applied to analyze past or present consumption patterns. Here, we quantify future land-based biodiversity footprints associated with three diverging Shared Socio-economic Pathways (SSPs), using loss in Biodiversity Intactness Index (BII) as an indicator of biodiversity loss. For each SSP, we retrieved socio-economic and land use projections to 2100 from the IMAGE-MAGNET model and calculated associated biodiversity footprints for seven aggregated world regions. We then compared these with the functional diversity component of the biosphere integrity planetary boundary. Our results indicate that the global land-based biodiversity impact stays below the boundary (tentatively set at 90% of original BII) in all scenario-year combinations. Contrastingly, the per capita boundary is transgressed in one, four and five out of the seven world regions in 2100 for SSP1 (‘sustainability’), SSP2 (‘middle of the road’) and SSP3 (‘regional rivalry’), respectively. These results indicate a strong difference in the biodiversity impact of final consumption between the regions and between SSPs. Even in the ‘sustainability’ scenario, the per capita biodiversity footprint of consumption in North America needs to be reduced to meet the per capita boundary. Thus, policy-making to safeguard the environment would benefit from adopting region-specific strategies: focusing on realizing agricultural efficiency gains in regions with unexploited potential, while focusing on promoting dietary changes towards less animal-based consumption in regions with limited potential for additional efficiency gains.     

Current situation of the ichnological locality of São Domingos from the Corda Formation (Lower Cretaceous), northern Tocantins state,Brazil

In the 80's, Leonardi treated the presence of a vertebrate ichnological locality from the Barremian Corda Formation, Parnaíba Basin, on the left bank of the Tocantins river, near of the São Domingos town, Itaguatins, State of Tocantins, Brazil. Originally, the record was composed of at least seven in situ trackways, accounting for fifty six tracks. Since 2011, the Hydroelectric Power Plant do Estreito has begun to work, causing the development of a water reservoir 160 km upstream to the ichnological site, causing periodic and highly energetic floods over the footprints-bearing level and altering it. The imprints are poorly to moderate preserved, but it is possible to distinguish the general morphology and the spatial arrangement of the footprints. The specimens are represented by pes imprints, mostly circular to subcircular, with no digital and claw impressions. No distinguishable manus imprints are present. The trackways are relative narrow with respect to the size of the tracks, so they are considered into the Parabrontopodus-like category. The São Domingos tracks have been originally assigned to iguanodontid dinosaurs, and posteriorly related to a sauropodian origin. This idea is herein accepted, particularly to a basal sauropod, basal macronarians, or diplodocoids. Up to date, the tracks from the São Domingos locality are the only vertebrate fossil record from the Corda Formation, meaning an important contribution to the Cretaceous ichnofauna from South America.