Assessing the carbon capture potential of reforestation project

Acknowledgements We acknowledge funding through the UP-Green-LCA (NE/P019668/1) and Soils-R-GGREAT (NE/P019498/1) projects of the greenhouse gas removal (GGR) programme. The GGR programme is financed by the UK Natural Environment Research Council (NERC), Engineering and Physical Science Research Council (EPSRC), Economic and Social Science Research Council (ESRC) and the UK department for Business, Energy and Industrial Strategy (BEIS). We thank CINCIA and its funders (USAID and WWF) for their help and support during this projectPeer reviewedPublisher PD

Ecohydrology and ecosystem services of a natural and an artificial bofedal wetland in the central Andes

High-altitude wetlands of the Central Andes, locally known as bofedales, provide important ecosystem services, particularly carbon storage, forage provisioning, and water regulation. Local communities have artificially expanded bofedales by irrigating surrounding grasslands to maximise areas for alpaca grazing. Despite their importance, biophysical processes of both natural and artificial bofedales are still poorly studied, which hinders the development of adequate management and conservation strategies. We analyse and compare the vegetation composition, hydrological variables, groundwater chemistry, and soil characteristics of a natural and an artificial bofedal of at least 10 years old in southern Peru, to understand their interrelations and the consequences for ecosystem service provisioning. We do not find statistically significant differences in the soil, water, and vegetation characteristics. Soil organic carbon (SOC) content, which we use as a proxy for carbon storage, is negatively correlated to dissolved oxygen, pH, and soil water temperature. In addition, Non-Metric Multidimensional Scaling analysis shows a positive relation between plant community composition, SOC content, and water electric conductivity. Our results suggest a three-way interaction between hydrological, soil, and vegetation characteristics in the natural bofedal, which also holds for the artificial bofedal. Vegetation cover of two of the most highly nutritious species for alpaca, Lachemilla diplophylla and Lilaeopsis macloviana with 19-22% of crude protein, are weakly or not correlated to environmental variables, suggesting grazing might be obscuring these potential relationships. Given the high economic importance of alpaca breeding for local communities, expanding bofedales artificially appears an effective strategy to enhance their ecosystem services with minimal impact on the ecohydrological properties of bofedales

PISCOeo_pm, a reference evapotranspiration gridded database based on FAO Penman-Monteith in Peru

A new FAO Penman-Monteith reference evapotranspiration gridded dataset is introduced, called PISCOeo_pm. PISCOeo_pm has been developed for the 1981–2016 period at ~1 km (0.01°) spatial resolution for the entire continental Peruvian territory. The framework for the development of PISCOeo_pm is based on previously generated gridded data of meteorological subvariables such as air temperature (maximum and minimum), sunshine duration, dew point temperature, and wind speed. Different steps, i.e., (i) quality control, (ii) gap-filling, (iii) homogenization, and (iv) spatial interpolation, were applied to the subvariables. Based on the results of an independent validation, on average, PISCOeo_pm exhibits better precision than three existing gridded products (CRU_TS, TerraClimate, and ERA5-Land) because it presents a predictive capacity above the average observed using daily and monthly data and has a higher spatial resolution. Therefore, PISCOeo_pm is useful for better understanding the terrestrial water and energy balances in Peru as well as for its application in fields such as climatology, hydrology, and agronomy, among others

Redefining Secondary Forests in the Mexican Forest Code: Implications for Management, Restoration, and Conservation

The Mexican Forest Code establishes structural reference values to differentiate between secondary and old-growth forests and requires a management plan when secondary forests become old-growth and potentially harvestable forests. The implications of this regulation for forest management, restoration, and conservation were assessed in the context of the Calakmul Biosphere Reserve, which is located in the Yucatan Peninsula. The basal area and stem density thresholds currently used by the legislation to differentiate old-growth from secondary forests are 4 m2/ha and 15 trees/ha (trees with a diameter at breast height of >25 cm); however, our research indicates that these values should be increased to 20 m2/ha and 100 trees/ha, respectively. Given that a management plan is required when secondary forests become old-growth forests, many landowners avoid forest-stand development by engaging slash-and-burn agriculture or cattle grazing. We present evidence that deforestation and land degradation may prevent the natural regeneration of late-successional tree species of high ecological and economic importance. Moreover, we discuss the results of this study in the light of an ongoing debate in the Yucatan Peninsula between policy makers, non-governmental organizations (NGOs), landowners and researchers, regarding the modification of this regulation to redefine the concept of acahual (secondary forest) and to facilitate forest management and restoration with valuable timber tree species

Natural Regeneration after Long-Term Bracken Fern Control with Balsa (Ochroma pyramidale) in the Neotropics

In many parts of the Neotropics, deforested areas are often colonized by the highly competitive invasive bracken fern (Pteridium aquilinum), which inhabits naturally regenerated forests and successional forests on abandoned farmland. Within the tropical forest region of Chiapas in southern Mexico, we implemented an experiment in 2005 to out-compete bracken fern infestation and reduce or eliminate live bracken rhizomes using several treatments: Direct sowing of balsa seeds (Ochroma pyramidale; Malvaceae), a traditional Lacandon treatment of scattering balsa seeds, transplanting balsa seedlings, and a control treatment (without balsa). For each treatment, we applied three different bracken weeding frequencies: No weeding, biweekly weeding, and monthly weeding. In this study, we present data gathered four years after establishing the experiment regarding: Bracken fern rhizome biomass, balsa density, basal area, height, density, species richness of naturally regenerating vegetation for all treatments, and bracken weeding frequencies. We also evaluated the importance of balsa and its regenerative attributes in controlling bracken fern by correlating it with remaining belowground live rhizome biomass. Living rhizome biomass was completely eradicated in all treatments with biweekly and monthly weeding. Density and species richness of a naturally regenerated species were negatively correlated with bracken fern rhizome biomass, and the density of this species was highest in areas with no rhizome biomass. Although balsa tree stands are effective short-term solutions for controlling rhizome biomass, the success of natural regeneration following balsa establishment can be critical to long-term elimination of bracken fern

Deforestation and Forest Degradation Due to Gold Mining in the Peruvian Amazon: A 34-Year Perspective

While deforestation rates decline globally they are rising in the Western Amazon. Artisanal-scale gold mining (ASGM) is a large cause of this deforestation and brings with it extensive environmental, social, governance, and public health impacts, including large carbon emissions and mercury pollution. Underlying ASGM is a broad network of factors that influence its growth, distribution, and practices such as poverty, flows of legal and illegal capital, conflicting governance, and global economic trends. Despite its central role in land use and land cover change in the Western Amazon and the severity of its social and environmental impacts, it is relatively poorly studied. While ASGM in Southeastern Peru has been quantified previously, doing so is difficult due to the heterogeneous nature of the resulting landscape. Using a novel approach to classify mining that relies on a fusion of CLASlite and the Global Forest Change dataset, two Landsat-based deforestation detection tools, we sought to quantify ASGM-caused deforestation in the period 1984–2017 in the southern Peruvian Amazon and examine trends in the geography, methods, and impacts of ASGM across that time. We identify nearly 100,000 ha of deforestation due to ASGM in the 34-year study period, an increase of 21% compared to previous estimates. Further, we find that 10% of that deforestation occurred in 2017, the highest annual amount of deforestation in the study period, with 53% occurring since 2011. Finally, we demonstrate that not all mining is created equal by examining key patterns and changes in ASGM activity and techniques through time and space. We discuss their connections with, and impacts on, socio-economic factors, such as land tenure, infrastructure, international markets, governance efforts, and social and environmental impacts

Natural infrastructure interventions and their effect on soil erosion mitigation in the Andes

The Andes region is prone to soil erosion because of its steep topographic relief, high spatio-temporal variability in precipitation and heterogeneity in lithological strength. Soil erosion by water is affecting natural and anthropogenic environments through its impacts on water quality and availability, loss of soil nutrients, flood risk, sedimentation in rivers and streams, and damage to civil infrastructure. Sustainable land and water management, referred here as natural infrastructure interventions, aims to avoid, reduce and reverse soil erosion and can provide multiple benefits for the environment, population and livelihoods. In this study, we present a systematic review of peer-reviewed and grey literature involving more than 120 local case-studies from the Andes. Three major categories of natural infrastructure interventions were considered: protective vegetation, soil and water conservation measures, and adaptation measures that regulate the flow and transport of water. The analysis was designed to answer the following research questions: (1) Which soil erosion indicators allow us to assess the effectiveness of natural infrastructure interventions across the Andean range? (2) What is the overall impact of implementing natural infrastructure interventions for on-site and off-site erosion mitigation? The systematic review shows that the effectiveness of protective vegetation on soil erosion mitigation is the most commonly studied characteristic, accounting for more than half of the empirical studies. From the suite of physical, chemical and biological indicators that were commonly used in soil erosion research, our review identified two indicators to be particularly suitable for the analyses of the effectiveness of natural infrastructure interventions: soil organic carbon (SOC) of the topsoil, and soil loss rates at plot scale. The implementation of soil and water conservation measures in areas under traditional agriculture had positive effects on SOC (1.28 to 1.29 times higher SOC than in agricultural land). Soil loss rates were 54% lower when implementing SWC than on cropland. When implementing SWC in rangeland, the data indicated an increase in soil loss rate by 1.54 times. Untreated degraded land is reported to have significantly higher soil loss and specific sediment yield compared to cropland. The results of this systematic review allows to assess the overall effectiveness of commonly used natural infrastructure interventions, which can guide policy and decision making in the Andes. Similarly, the review identified critical gaps in knowledge that must be attended by more comprehensive research to consider the high spatiotemporal variability of the Andes region

The effect of natural infrastructure on water erosion mitigation in the Andes

To expand the knowledge base on natural infrastructure for erosion mitigation in the Andes, it is necessary to move beyond case by case empirical studies to comprehensive assessments. This study reviews the state of evidence on the effectiveness of interventions to mitigate soil erosion by water and is based on Andean case studies published in gray and peer-reviewed literature. Based on a systematic review of 118 case studies from the Andes, this study addressed the following research questions. (1) Which erosion indicators allow us to assess the effectiveness of natural infrastructure? (2) What is the overall impact of working with natural infrastructure on on-site and off-site erosion mitigation? (3) Which locations and types of studies are needed to fill critical gaps in knowledge and research? Three major categories of natural infrastructure were considered: restoration and protection of natural vegetation, such as forest or native grasslands, forestation with native or exotic species and implementation of soil and water conservation measures for erosion mitigation. From the suite of physical, chemical and biological indicators commonly used in soil erosion research, two indicators were particularly relevant: soil organic carbon of topsoil and soil loss rates at plot scale. The protection and conservation of natural vegetation has the strongest effect on soil quality, with 3.01±0.893 times higher soil organic carbon content in the topsoil compared to control sites. Soil quality improvements are significant but lower for forestation and soil and water conservation measures. Soil and water conservation measures reduce soil erosion to 62.1g %g ±g 9.2g %, even though erosion mitigation is highest when natural vegetation is maintained. Further research is needed to evaluate whether the reported effectiveness holds during extreme events related to, for example, El Niño-Southern Oscillation. © 2022 Veerle Vanacker et al