The Role of Physical and Political Factors on the Conservation of Native Vegetation in the Brazilian Forest-Savanna Ecotone

The AraguaiaRiver Basincovers a considerable extent of Brazilian Savanna (locally called Cerrado) and part of Amazon Tropical Rainforest, embracing high biodiversity and a vast flooding area. This region has been converted to agricultural lands since 1970s, for the past four decades, leading to a fragmented landscape that holds one of the few large remaining blocks of Cerrado primary vegetation. Therefore, to assess the degree of preservation of this area a 2007 primary vegetation map was derived through Boolean operations using land use and land cover maps from 1975, 1985, 1996 and 2007, from digital classification of Landsat MSS and TM images. To evaluate the role of driving factors on the presence of pristine vegetation, a logistic regression analyses was performed. Tested factors were: distance from roads and cities, terrain slope, land tenure, soil fertility and flooding. We found statistical significant values (p nous lands, wetlands and areas with low fertility have positive influence on the presence and maintenance of these pristine areas. The occurrence of original vegetation in many cases is associated with environmental constraints that difficult or do not allow agricultural use. Analysis of physical and political factors, which may have direct or indirect influence on the conservation and degradation of native vegetation are very important for the comprehension of the dynamics of regional land use, and provide supporting information for a more efficient and sustainable regional landscape planning.

Urban heat mitigation by green and blue infrastructure:Drivers,effectiveness,and future needs

The combination of urbanization and global warming leads to urban overheating and compounds the frequency and intensity of extreme heat events due to climate change.Yet,the risk of urban overheating can be mitigated by urban green-blue-grey infrastructure(GBGI),such as parks,wetlands,and engineered greening,which have the potential to effectively reduce summer air temperatures.Despite many reviews,the evidence bases on quantified GBGI cooling benefits remains partial and the practical recommendations for implementation are unclear.This systematic literature review synthesizes the evidence base for heat mitigation and related co-benefits,identifies knowledge gaps,and proposes recommendations for their implementation to maximize their benefits.After screening 27,486 papers,202 were reviewed,based on 51 GBGI types categorized under 10 main divisions.Certain GBGI(green walls,parks,street trees)have been well researched for their urban cooling capabilities.However,several other GBGI have received negligible(zoological garden,golf course,estuary)or minimal(private garden,allotment)attention.The most efficient air cooling was observed in botanical gardens(5.0±3.5℃),wetlands(4.9±3.2℃),green walls(4.1±4.2℃),street trees(3.8±3.1℃),and vegetated balconies(3.8±2.7℃).Under changing climate conditions(2070–2100)with consideration of RCP8.5,there is a shift in climate subtypes,either within the same climate zone(e.g.,Dfa to Dfb and Cfb to Cfa)or across other climate zones(e.g.,Dfb[continental warm-summer humid]to BSk[dry,cold semi-arid]and Cwa[temperate]to Am[tropical]).These shifts may result in lower efficiency for the current GBGI in the future.Given the importance of multiple services,it is crucial to balance their functionality,cooling performance,and other related co-benefits when planning for the future GBGI.This global GBGI heat mitigation inventory can assist policymakers and urban planners in prioritizing effective interventions to reduce the risk of urban overheating,filling research gaps,and promoting community resilience.

Impact of Land Degradation on Soil Microbial Biomass and Activity in Northeast Brazil

Land degradation causes great changes in the soil biological properties.The process of degradation may decrease soil microbial biomass and consequently decrease soil microbial activity.The study was conducted out during 2009 and 2010 at the four sites of land under native vegetation(NV),moderately degraded land(LDL),highly degraded land(HDL) and land under restoration for four years(RL) to evaluate changes in soil microbial biomass and activity in lands with different degradation levels in comparison with both land under native vegetation and land under restoration in Northeast Brazil.Soil samples were collected at 0-10 cm depth.Soil organic carbon(SOC),soil microbial biomass C(MBC) and N(MBN),soil respiration(SR),and hydrolysis of fluorescein diacetate(FDA) and dehydrogenase(DHA) activities were analyzed.After two years of evaluation,soil MBC,MBN,FDA and DHA had higher values in the NV,followed by the RL.The decreases of soil microbial biomass and enzyme activities in the degraded lands were approximately 8-10 times as large as those found in the NV.However,after land restoration,the MBC and MBN increased approximately 5-fold and 2-fold,respectively,compared with the HDL.The results showed that land degradation produced a strong decrease in soil microbial biomass.However,land restoration may promote short-and long-term increases in soil microbial biomass.