Heavy metal pollution is not only a hazard to living organisms but also an important worldwide environmental concern. Experiments were performed to investigate the physiological mechanisms of magnetic (Fe₃O₄) nanoparticles (nano-Fe₃O₄) mitigation of the toxicity of heavy metals (Pb, Zn, Cd and Cu) in wheat seedlings. All the Petri dishes with germinating seedlings (1d) were covered, sealed with parafilm, and placed in a dark growth chamber. All parameters (seedling growth inhibition, heavy metal accumulation, enzymatic activities, and reducing effects of nano-Fe₃O₄ on heavy metal toxicity) were analyzed only after five days. The results showed that the tested heavy metals significantly affected the growth of wheat seedling by decreasing root length, shoot length and even death at 10 mM concentration in the case of Cd and Cu. Heavy metals exposure also showed that superoxide dismutase (SOD) and peroxidases (POD) activities decreased significantly when the malondialdehyde (MDA) content was significantly higher in wheat seedlings. Addition of magnetic (Fe₃O₄) nanoparticles (2000 mg/L) in each heavy metal solution (1 mM) significantly decreased the growth inhibition and activated protective mechanisms to reduce oxidative stress induced by heavy metals in the wheat seedlings. The reducing effects of nano-Fe₃O₄ against heavy metals stress could be dependent on the increase in the enzyme activity (SOD and POD). Their protective role was confirmed by the decrease in MDA content. The alleviating effect of nano-Fe₃O₄ is associated with their adsorption capacity of heavy metals.

ITM Web of Conferences, open-access proceedings in information technology, computer science and mathematics

The High Niger National Park is one of the most important protected areas for biodiversity conservation in Guinea. This study examined the temporal evolution of the bushmeat trade in three rural markets in the Park and in the nearest urban centre, Faranah. We collected data in markets during August–November 2017 in three villages around the Mafou core area of the Park and in Faranah, and compared these data with equivalent published data from the same rural areas in 2001 and 2011 and from Faranah in 1994, 1995, 1996 and 2011. Across all study periods, mammals predominated in the bushmeat trade. In rural markets we noted a marked increase in the number of carcasses and biomass offered for sale from 2001 onwards, whereas in Faranah there were no differences over time other than a peak in 1996. Overall, there was an increase in the sale of smaller sized species (< 10 kg), and a marked increase in the sale of species that forage on crops, including the green monkey Chlorocebus sabaeus and warthog Phacochoerus africanus, in spite of religious taboos against the consumption of primates and Suidae. Green monkeys were not sold in markets during the 1990s but were the dominant species in Faranah in 2011 and 2017. Our findings suggest a marked shift in traded species, associated with crop protection by farmers and economic incentives to kill and trade crop-foraging species. This study highlights the value of a longitudinal perspective for investigating the dynamic relationship between local livelihoods and biodiversity conservation.

For centuries, human communities have relied on natural resources to satisfy their various needs (food, health, housing, etc.). Among these resources, Terminalia superba, a wood of high technological quality, is highly sought-after, which has led to strong pressure on its natural populations throughout its range, including Guinea. The present study assessed the factors determining the use and conservation of the species in Forest Guinea. Specifically, it aimed to i) assess the factors affecting the use values of T. superba, and ii) analyze the socio-economic factors controlling the conservation of Terminalia superba by rural communities. Data were collected on a random sample of 354 people in three prefectures (Lola, Macenta and N'Zérékoré) of Guinée Forestière. The relative frequency of users of the species (all forms of use combined) was calculated, and through a generalized linear model based on the Poisson distribution, the relationship between use values and respondents' socio-economic factors was analyzed. Logistic regression in a step-by-step selection approach was used to identify the factors controlling the retention of Terminalia superba plants in the fields. The relative frequency of use of Terminalia superba was 99.15%. The average number of uses reported per respondent was 1.92, with a coefficient of variation of 49.72%. Of all the factors involved, only gender had a significant effect on the number of uses reported, with men reporting more uses (mean = 1.97 and CV = 48.72%) than women (mean = 1.06 and CV = 22.91%). The final logistic regression model identified variables such as prefecture of residence, time spent in the village over 20 years, monthly income, main source of income, age category, marital status and level of education as factors controlling the retention of Terminalia superba plants by respondents in their fields. This study demonstrates the importance of the species and identifies the socio-economic factors of interest to be considered in programs for its valorization and conservation.