Recent Submissions
Holocene patterns of peat accumulation in Peruvian Amazonia
(Elsevier, 2026-03-15) Lawson, Ian T.; Åkesson, Christine M.; Dargie, Greta C.; del Águila Pasquel, Jhon; Draper, Frederick C.; Hastie, Adam; Kelly, Thomas J.; Sassoon, D.; Abraham, V.; Baker, Timothy R.; Fabel, D.; Gulliver, P.; Honorio Coronado, Eurídice; Roucoux, Katherine H.
Peatlands accumulate and store carbon over centuries to tens of millennia. Analysing the age structure of peatlands helps us to understand their genesis, development, and stability as carbon stores, and informs peatland management. Here we analyse new and previously published radiocarbon dates from peatlands in the Pastaza-Maran ̃on ́ Basin in Peru, the largest known peatland complex in Amazonia. We show that peatlands here are younger (< c. 8900 and frequently <2500 years old) than in many other parts of the tropics. Basal peat ages in extant peatlands vary depending on the geomorphological stability of the landscape, with younger basal dates typically occurring close to active river floodplains and older basal dates in more stable contexts. The data indicate that within individual peatlands, peat initiation may occur synchronously across a basin, or peat may spread laterally from one or more nucleation sites. Only two out of seven well-dated records show clear hiatuses in past peat accumulation, suggesting that carbon sequestration in some, but not all peatlands has been vulnerable to landscape hydrological change or climate change. Peatland ecosystems in the region are economically important sources of non-timber forest products, which it may be possible to harvest sustainably without biomass loss or drainage, but our analysis indicates that the peat itself accumulates too slowly to be considered as a renewable resource on economically meaningful timescales.
Integrative taxonomy uncovers Clinostomum chaacci and an unidentified congeneric metacercaria infecting Hoplosternum littorale (Siluriformes: Callichthyidae) in the Peruvian Amazon Basin
(Elsevier, 2025-11-27) Chero, Jhon Darly; Ñacari, L.A.; Murrieta Morey, Germán; Cruces, Celso Luis; Cacique, E.; Huaman, N.; Lopez, D.; Mondragón-Martínez, Aarón; Martínez-Rojas, Rosa; Yunis Aguinaga, Jefferson
Clinostomum Leidy, 1856 is a cosmopolitan genus of digenean trematodes whose metacercariae commonly infect freshwater fishes and amphibians as second intermediate hosts. In South America, the diversity and taxonomy of Clinostomum metacercariae remain poorly understood, due in part to the morphological similarity of larval stages and the scarcity of molecular data. This study provides the first integrative evidence of two phylogenetically distinct Clinostomum lineages infecting the callichthyid catfish Hoplosternum littorale (Hancock, 1828) (Siluriformes: Callich- thyidae), a benthic catfish of commercial and subsistence importance in the Peruvian Amazon. Morphological analyses (light and scanning electron microscopy) combined with molecular data from mitochondrial (cox1) and nuclear (28S rDNA) market revealed two lineages with clear genetic differentiation. Specimens from Loreto were conspecific with Clinostomum chaacci Sereno-Uribe, Lopez-Jim ́ ́enez, Gonz ́alez-García, Ortega-Olivares & García-Varela, 2025, previously re-ported from several fish hosts across Central and South America, whereas those from Ucayali formed a distinct and highly divergent lineage (11.9–12.7 % cox1 divergence) closely related to Clinostomum L1, representing a potentially undescribed species. The detection of C. chaacci in H. littorale constitutes a new host record and expands the known distribution of this species to the western Amazon Basin. The detection of Clinostomum metacercariae in fish muscle tissue raises potential zoonotic concerns, especially in regions where raw or undercooked fish is consumed. These findings underscore the need for integrative taxonomic approaches to unravel hidden
Variability in Fruit Production of Carapa guianensis Associated with Edaphoclimatic Factors in the Amazon
(MDPI, 2026-02-10) Angulo Villacorta, Carlos Darwin; Silva da Conceição, Denilson; Chunchon Remon, Rodolfo Juan; Manigat, Donald; Antunes Jimenez, Lorena; De Toledo, José Julio
Carapa guianensis Aubl., widely distributed throughout the Amazon, is recognized for its ecological, economic, and social importance, and constitutes a key source of income for numerous extractive communities. However, fruit production exhibits marked spatial variation that may be influenced by soil properties and climatic factors. In this study, we assessed this variability using data from 21 studies conducted in the Brazilian Amazon, incorporating georeferenced information from each site on climate and soil characteris-
tics. Environmental variables were evaluated using Random Forest models. Although the number of independent production estimates available in the literature is limited, average fruit productivity showed a broad range (0.34 to 34.6 kg·tree−1·year−1), with higher values in várzea forests (16.5 kg·tree−1·year−1) and lower values in igapó forests (2.5 kg·tree−1
·year−1). The Random Forest model explained 42% of the variability in fruit
production according to cross-validation, whereas the model fit using the full dataset showed a higher R2 value (0.83). Soil organic carbon, mean annual temperature, and clay content were the most influential predictors. These findings demonstrate that fruit production is shaped by the interaction between edaphic and climatic conditions, which determine the species’ productivity patterns and highlight the need to foster adaptive management strategies that ensure the sustainable use of andiroba across Amazonian
ecosystems. Nevertheless, it is acknowledged that the number of available production estimates is limited and that methodological heterogeneity exists among the analyzed studies. Despite this, the results reveal consistent patterns of association between Carapa guianensis fruit production and edaphoclimatic gradients, highlighting the influence of climatic and soil-related variables at a regional scale.
Protocol for in vitro germination and micropropagation of Himatanthus Sucuuba (Spruce ex Müll. arg.) Woodson
(Scientia Agropecuaria, 2026-02-16) Sáenz Ramírez, Lyanna H.; Revilla Chávez, Jorge; Ramírez Flores, Noe; Imakawa, Angela Maria; Barbosa Sampaio, Paulo de Tarso
Himatanthus sucuuba is important in folk medicine and is widely used as an antitumor, antifungal, vermifuge and anti-anemic agent1. In this context, the objective of this study was to develop a protocol for in vitro germination and micropropagation of H. sucuuba. The seeds were immersed in a 1.0% (v/v) Cabrio Top solution for one hour on a magnetic stirrer and then in a 0.1% (v/v) diluted NaOCl solution for 30 minutes under agitation, followed by immersion in 70% alcohol for 1 minute. Subsequently, the seeds were rinsed four times with sterile distilled water and then inoculated in MS medium supplemented with the auxins AIA, ANA and AIB at concentrations of 0.0; 1.0; 3.0; 5.0 mg L-1. The experimental design was completely randomized, using 10 treatments with 3 replicates of 10 seeds (n = 30). It was observed that the MS medium supplemented with IAA (5.0 mg L-1) resulted in 80% germination and seedlings with 5.97 cm in height and 4.2 nodal segments. To stimulate rooting, the nodal segments were cut and inoculated in MS medium supplemented with BAP (0.1 mg L-1) and in interaction with the auxins IAA, 2,4-D and ANA, at concentrations of 0.0; 3.0; 5.0 and 8.0 mg L-1 and kept in a growth room at 25 ± 2 °C, with a photoperiod of 16 h. The combination BAP+IAA (0.1 + 8.0 mg L-1) showed the best results with 100% sprouting, 40% callus formation and 30% rooting. In conclusion, in vitro propagation is a promising technique to produce H. sucuuba seedlings, however, hormonal adjustments are necessary.
Soil functioning indicators decline with land-use intensification in the Peruvian Amazon: evidence from Ucayali
(Frontiers, 2026-03-04) Abanto Rodríguez, Carlos; Guerra Blas, Juan Carlos; Castillo Torres, Dennis del; Ramírez Flores, Noe; Gonzalo García, Diego; Moya Ambrosio, María Fernanda; Guerra Arévalo, Héctor; Guerra Arévalo, Wilson; Bravo, Jhon Alison; Panduro Tenazoa, Nadia; Tadashi Sakasaki, Roberto; Monteiro Neto, João Luiz Lopes; Revilla Chávez, Jorge; Murga Orrillo, Hipólito
Rapid land-use change in the Peruvian Amazon threatens soil processes that sustain productivity and ecosystem resilience. This study assessed soil functioning indicators along a land-use intensification gradient in Ucayali, Peru.Methods: We evaluated physicochemical (texture fractions, pH, organic matter, cation-exchange capacity, carbon, and micronutrients) and biological indicators (cultivable microbial groups, microbial biomass carbon, respiration, and macrofauna) from 54 independent composite topsoil samples (0–20 cm) across seven land-use systems, multiple localities, and soil texture classes. Principal component analysis and univariate tests were applied to identify multivariate gradients and significant differences among groups. PCA revealed a dominant texture–fertility gradient contrasting sand-rich soils with finer-textured soils associated with higher CEC, organic matter, total carbon, and micronutrients (notably Mn and Cu). Significant differences among land-use systems were detected for CEC, OM, Mn, pH, Cu, SOC, and sand. Cacao agroforestry differed from pasture and oil palm systems in key fertility indicators. Biological indicators showed weaker global separation, although macrofauna differed significantly among land uses. Soil texture modulated baseline fertility and the expression of land-use impacts. Cacao agroforestry and secondary forests occupied transitional positions between forests and intensive systems. A reduced monitoring set including texture fractions, OM, CEC, pH, Mn, and selected biological metrics is recommended for tracking soil degradation in heterogeneous Amazonian landscapes.