A Review of Small Farmer Land Use and Deforestation in Tropical Forest Frontiers: Implications for Conservation and Sustainable Livelihoods

Understanding how management can prevent degradation of the structurally fragile soils of the Amazonian periphery

The dynamics and responses to mulching management processes, which affect sustainability in tropical agroecosystems, remain poorly understood. Therefore, this study aims to evaluate and distinguish the short-and long-term effects of mulch of leguminous biomass on fertility of a tropical soil enriched with calcium. This experiment was conducted using the treatments: Long-term mulching (LTM) consisted of planting without mulch in 2019 in soil that had been mulched for six years previously, while short-term mulching (STM) consisted of planting without mulch for six years and with mulch only in 2019. LTM + STM consisted of planting in mulched soil for seven years (from 2013 to 2019), while LTM + synthetic nitrogen (LTM + sN) consisted of the LTM treatment with the addition of 150 kg N ha-1. The remaining treatments were STM + sN; LTM + STM + sN; bare soil with sN, and bare soil without sN as control. In areas with LTM the interactions between products derived from biomass, sN, and Ca resulted in higher total SOC and BS, while STM maintained soil moisture, decreased penetration resistance, and enhanced N uptake providing biological nitrogen able to replace sN for maize nutrition. The positive effects of short- and long-term mulching were cumulative as they increased accumulated N by maize in 163%, and maize grain yield by 125% (4.77-10.78 Mg ha-1) compared to cultivation with sN without mulch. Our results showed that interactions between continuos mulch of leguminous biomass, Ca and sN prevent degradation of agricultural land in Amazonian conditions. Therefore, this combination must be recommended to prevent Amazonian soil management, which in turn reduces the risk of new deforestation in Amazonian periphery.

Carbon balance of plywood from a social reforestation program in Indonesia

Social reforestation programs plant trees on degraded, uncultivated land in low-income regions to allow the local population to generate income from selling wood products and-in case of agroforestry systems-to grow food. For fundraising it is of interest to demonstrate not only positive social impacts but also environmental ones. Proving negative greenhouse gas (GHG) emissions would allow the programs to enter the market for carbon offsetting projects and liberate further funding. In a case study, a social reforestation program in Kalimantan, Indonesia, is analyzed. GHG emissions (according to ISO 14067, PAS 2050 and EU ILCD Handbook for LCA) of the main product, laminated veneer lumber plywood, are determined as 622 and 21 kg CO2-e/m3 for short-term and long-term (above 100 years) plywood use, respectively. Switching to lignin-based resins and renewable electricity could reduce emissions down to - 363 kg CO2-e/m3 for long-term use. The analyzed agroforestry system produces almost carbon-neutral plywood today and could be climate positive in the mid-term.

Advancing the understanding of forest conservation dynamics through livelihood and landscape change scenarios: a case study in Chiapas, Mexico

Forest conversion and conservation in rural settings are linked to both social and biophysical drivers. However, the joint analysis of these drivers presents methodological challenges. To address this problem, we propose a novel methodology to explore the relationship between livelihood heterogeneity and land use change at the community level. It combines the concept of archetype with the accounting scheme of MUlti-Scale Integrated Analysis of Societal and Ecosystem Metabolism to define and quantify the characteristics of livelihood typologies in socioeconomic (time use, financial flows) and ecological terms (land use, agricultural inputs, soil degradation). Conservation trade-offs of potential policies are explored through "what if" scenarios assuming changes in off-farm opportunities, population growth, and conservation/farming subsidies. The approach is tested with a case study of the community of San Isidro, in Chiapas, Mexico. We conclude that the concept of livelihood typologies is useful to inform the debate over conservation prospects in rural environments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10668-023-02965-z.

Multitemporal Spatial Analysis of Land Use and Land Cover Changes in the Lower Jaguaribe Hydrographic Sub-Basin, Ceará, Northeast Brazil

Aquaculture is currently one of the fastest growing food production systems globally, and shrimp is considered one of the most highly valued products. Our study area is the lower Jaguaribe River sub-basin (LJRSB), located in the northeastern part of Ceará in Brazil. The aquaculture activity in this area began in the early 1990s and is currently one of the largest shrimp producers in Brazil. This study generated a spatial-temporal analysis of vegetation index and land use and land cover (LULC) using remote sensing images from Landsat satellites processed using geographic information systems (GIS). The findings showed an increase in the water bodies class where shrimp farms are found. In addition, to help us discuss the results, data from the Global Surface Water Explorer was also used to understand this change throughout intra and interannual water variability. Besides shrimp farms’ intensification, agricultural areas in the LJRSB also increased, mainly in the irrigated perimeter lands (IPLs), causing a loss in the Caatinga native vegetation. In summary, over recent years, significant changes have been noticeable in the LJRSB coastal region, caused by an increase in shrimp farms mainly located on the Jaguaribe River margins, destroying the native riparian forest.