Regeneração de espécies lenhosas sob a influência do bambu Actinocladum verticillatum (Nees) McClure ex Soderstr. (Poaceae) em cerradão e cerrado típico na transição Cerrado-Amazônia

In this study, we analyzed and compared the floristic composition, species richness and diversity, and structure of the natural regeneration of two phytophysiognomies (savanna forest and typical cerrado) under the effect of natural clumps of the bamboo Actinocladum verticillatum (Nees) McClure ex Soderstr. at the Bacaba City Park, Nova Xavantina municipality (Mato Grosso state, Brazil). In each phytophysiognomy, we established 15 contiguous plots in a bamboo-free control site (NB) and 15 in a site densely occupied by bamboos (WB). The natural regeneration and the woody vegetation (WV, diameter ≥ 3 cm at 30 cm above ground) were sampled in plots of 1 x 1 m, 2 x 2 m, 5 x 5 m (natural regeneration) and 10 x 10 m (WV). In the natural regeneration, we found 55 species in the savanna forest (NB = 49, WB = 34) and 76 in the typical cerrado (NB = 68, WB = 51). Overall, the NB sites from both phytophysiognomies had the highest values of species diversity, evenness and abundance of individuals, which indicates a possible interference of the clumps with the structure of the natural regeneration. The occurrence of Brosimum gaudichaudii Trécul and Myrcia splendens (Sw.) DC at most stages of regeneration highlights their potential for the recovery of lands occupied by these clumps.No presente estudo foram analisadas e comparadas a composição florística, riqueza, diversidade de espécies e a estrutura da regeneração natural em duas fitofisionomias (cerradão e cerrado típico) sob o efeito de adensamentos naturais do bambu Actinocladum verticillatum (Nees) McClure ex Soderstr. no Parque Municipal do Bacaba, Nova Xavantina-MT. Em cada fitofisionomia foram alocadas 15 parcelas contíguas em um sítio controle, com ausência completa de bambu (SB) e 15 em um sítio com bambu (CB). A regeneração natural e a vegetação lenhosa (VL, ≥ 3 cm de diâmetro a 30 cm do solo) das duas fitofisionomias foram amostradas em parcelas de 1 x 1 m, 2 x 2 m, 5 x 5 m (regeneração natural) e 10 x 10 m (VL). Foram encontradas, na regeneração natural, 55 espécies no cerradão (SB = 49 e CB = 34) e 76 no cerrado típico (SB = 68 e CB = 51). De forma geral, os sítios SB nas duas fitofisionomias detiveram os maiores valores de diversidade de espécies, equabilidade e abundância de indivíduos, o que indica possível interferência dos adensamentos na estrutura da regeneração natural. A ocorrência de Brosimum gaudichaudii Trécul e Myrcia splendens (Sw.) DC. na maioria dos estádios da regeneração, reforça o potencial dessas espécies na recuperação de áreas ocupadas por estes adensamentos.

Tree diversity and above-ground biomass in the South America Cerrado biome and their conservation implications

Less than half of the original two million square kilometers of the Cerrado vegetation remains standing, and there are still many uncertainties as to how to conserve and prioritize remaining areas effectively. A key limitation is the continuing lack of geographically-extensive evaluation of ecosystem-level properties across the biome. Here we sought to address this gap by comparing the woody vegetation of the typical cerrado of the Cerrado–Amazonia Transition with that of the core area of the Cerrado in terms of both tree diversity and vegetation biomass. We used 21 one-hectare plots in the transition and 18 in the core to compare key structural parameters (tree height, basal area, and above-ground biomass), and diversity metrics between the regions. We also evaluated the effects of temperature and precipitation on biomass, as well as explored the species diversity versus biomass relationship. We found, for the first time, both that the typical cerrado at the transition holds substantially more biomass than at the core, and that higher temperature and greater precipitation can explain this difference. By contrast, plot-level alpha diversity was almost identical in the two regions. Finally, contrary to some theoretical expectations, we found no positive relationship between species diversity and biomass for the Cerrado woody vegetation. This has implications for the development of effective conservation measures, given that areas with high biomass and importance for the compensation of greenhouse gas emissions are often not those with the greatest diversity

ALICE upgrades during the LHC Long Shutdown 2

International audienceA Large Ion Collider Experiment (ALICE) has been conceived and constructed as a heavy-ion experiment at the LHC. During LHC Runs 1 and 2, it has produced a wide range of physics results using all collision systems available at the LHC. In order to best exploit new physics opportunities opening up with the upgraded LHC and new detector technologies, the experiment has undergone a major upgrade during the LHC Long Shutdown 2 (2019–2022). This comprises the move to continuous readout, the complete overhaul of core detectors, as well as a new online event processing farm with a redesigned online-offline software framework. These improvements will allow to record Pb-Pb collisions at rates up to 50 kHz, while ensuring sensitivity for signals without a triggerable signature