Articles publicats (Ciència i Enginyeria Forestal i Agrícola)
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- ItemOpen AccessUAVs for monitoring responses of regenerating forests under increasing climate change-driven droughts - a review(IOP Publishing, 2023) Luber, A.; Ramachandran, V.; Jaafar, W.S.W.M.; Bajaj, Shaurya; Miguel Magaña, Sergio de; Cardil Forradellas, Adrián; Doaemo, Willie; Mohan, MidhunThe impact of climate change-driven droughts on regenerating forests is poorly understood due to the complexities involved in regeneration processes and the difficulties in measuring the relevant parameters with sufficient spatial and temporal resolution in a timely manner. Drought increases tree mortality in both undisturbed and disturbed forests and may influence forest regeneration dynamics from seed germination to the recruitment, growth, and survival of tree seedlings. Seedlings and small saplings may be more susceptible to changes in water availability than larger individuals due to their shallower roots that may be unable to reach the deeper, moist soil layers, and due to uneven competition with adult trees for soil moisture. The potential range shifts and local extinction of drought-sensitive species can also result in changes in forest species community composition and diversity loss at different scales. There is a need for precise and low-cost monitoring systems that facilitate better capturing of the complexities of such processes for restoration measures. The objective of this paper is to study the use of UAVs (Unmanned Aerial Vehicles) for monitoring responses of regenerating forests under increasing climate change-driven droughts. UAVs have several advantages over traditional field-based monitoring techniques and flexibility in selecting the required spatiotemporal resolution over other remote sensing methods, making them a promising tool for monitoring forest recovery. Although further research is required to ensure the accuracy and effectiveness of UAV-facilitated measures for monitoring forest regeneration, UAVs possess great potential in forest management in the event of increasing occurrences of climate-change driven droughts.
- ItemOpen AccessLate-vegetative and reproductive-stage nitrogen determinants of kernel weight in maize(Elsevier, 2023) Olmedo Pico, Lia B.; Savin, Roxana; Schussler, Jeffrey R.; Vyn, Tony J.Differences in maize kernel weight (KW) due to soil N availability have usually been associated with the indirect role that N plays in the prevailing source-sink balance for carbon at the canopy level during reproductive development. Additionally, KW changes have also been described in response to N assimilate supply to the reproductive tissues (i.e., direct N role). Our objective was to determine the most important source factors driving KW gains with varying N and dry matter supply via the multivariate study of pertinent phenotypic relationships during late vegetative and reproductive growth. Maize responses to N rate plus N timing and(or) plant density treatments were followed in five field experiments. Principal component analyses (PCA) and partial least square (PLS) regressions explored the relationships between final KW, plant-component biomass (DM), plant-component N concentrations, N uptake at V12, R1, R3, and R6 stages, plus specific grain-filling parameters including effective grain-filling rate (EGFR), grain-filling duration (GFD), and the kernel N accumulation features of rate and duration (KNAR and KNAD, respectively). Across experimental sites, grain yields at the highest N rate were 93-196 % above those with zero N. These yield increases coincided with incremental gains in both kernel number and KW at maturity. Via PCA, final KW was more positively correlated with vegetative-tissue N concentrations (stem N % at V12 and R1, leaf N % at R1 and R3) than with biomass during the critical period. In addition, final KW was more correlated with stem biomass at R6 than at V12, R1 or R3 stages. Via PLS, the majority of KW variability was explained by critical-period N contents, either in leaf (V12 and R1) or stem (R3), while at R6 stem DM was more important in KW determination. Finally, when tested against its physiological determinants, KW at maturity was largely associated with KNAR (via PCA) and EGFR (via PLS) during the grain-filling period. Overall, these results suggest the dual importance of N in determining KW at maturity through both leaf and stem N supply during the critical period and through dry matter allocation during the effective grain filling period.
- ItemOpen AccessEcosystem services provision by Mediterranean forests will be compromised above 2ºC warming(Wiley, 2021-07-06) Morán Ordóñez, Alejandra; Ramsauer, Julia; Coll Mir, Lluís; Brotons, Lluís; Améztegui González, AitorForests provide a wide range of provisioning, regulating and cultural services of great value to societies across the Mediterranean basin. In this study, we reviewed the scientific literature of the last 30 years to quantify the magnitude of projected changes in ecosystem services provision by Mediterranean forests under IPCC climate change scenarios. We classified the scenarios according to the temperature threshold of 2℃ set by the Paris Agreement (below or above). The review of 78 studies shows that climate change will lead to a general reduction in the provision of regulating services (e.g. carbon storage, regulation of freshwater quantity and quality) and a general increase in the number of fires, burnt areas and generally, an increase in climate-related forest hazards (median + 62% by 2100). Studies using scenarios above the 2℃ threshold projected significantly more negative changes in regulating services than studies using scenarios below this threshold. Main projected trend changes on material services (e.g. wood products), were less clear and depended on (i) whether or not the studies considered the interaction between the rise in temperatures and other drivers (e.g. forest management, CO2 fertilization) and (ii) differences in productivity responses across the tree species evaluated. Overall, the reviewed studies projected significant reductions in range extent and habitat suitability for the most drought-sensitive forest species (e.g. −88% Fagus sylvatica), while the amount of habitat available for more drought-tolerant species will remain stable or increase; however, the magnitude of projected change for these more xeric species was limited when high-end extreme climatic scenarios were considered (above Paris Agreement). Our review highlights the benefits that climate change mitigation (to keep global mean temperature increase <2℃) can bring in terms of service provision and conservation of Mediterranean forests.
- ItemOpen AccessFirst report of glyphosate resistance in an Amaranthus palmeri population from Europe(WILEY, 2023) Manicardi, Alfredo; Milani, Andrea; Scarabel, Laura; Mora, Germán; Recasens i Guinjuan, Jordi; Llenes; José María Montull; Joel TorraThe invasive weed Amaranthus palmeri is spreading throughout Spain, with Catalonia being one of the most affected regions. For this species, acetolactate synthase-inhibiting herbicide-resistant populations have been reported, and now glyphosate resistance is also suspected. Glyphosate targets and inhibits the enzyme 5-enolpyruvylshikimate3-phosphate synthase (EPSPS), but A. palmeri has evolved different resistant mechanisms leading to plant survival. One of the most effective is the EPSPS overexpression due to copy number variation (CNV). Gene copies accumulate within the EPSPS cassette that is an extrachromosomal circular DNA displaying unique structural polymorphisms. This study aims to determine the response to glyphosate of a suspected resistant population collected from a roadside and investigate the resistance mechanism involved. The herbicide bioassay confirmed that 40% of the plants survived glyphosate applied at 540 g a.i. ha 1 . No known mutations endowing glyphosate resistance were found at EPSPS amongst confirmed resistant plants, while in most of them (70%) specific molecular markers revealed the presence of the EPSPS cassette. All these results indicate that this population is glyphosate resistant and it is very likely that the EPSPS gene CNV is the main resistance mechanism. This is the first case of glyphosate resistance in A. palmeri in Europe whose introduction is likely due to importation of contaminated seed with glyphosate-resistant Palmer amaranth from the Americas. This introduction poses a significant danger to summer crops in our continent.
- ItemOpen AccessDifferent non-target site mechanisms endow different glyphosate susceptibility in avena species from Spain(MPDI, 2023) Vázquez-García, José G.; Torra Farré, Joel; Palma-Bautista, Candelario; Bastida, Fernando; Alcántara-de la Cruz, Ricardo; Portugal, João; Jorrin-Novo, Jesus V; Prado, Rafael DeIn recent decades, cereal agriculture across main producing areas in Spain has progressively adopted direct sowing, associated with an increased use of herbicides in pre-sowing. Weedy species from genus Avena have been observed after the application of glyphosate in wheat. Here, Avena fatua (two accessions), Avena byzantina and Avena sterilis subsp. sterilis, one accession each, were taxonomically characterized by a biometric study. Dose-response trials confirmed that one A. fatua accession evolved to resistance, because it was four times more resistant (R) than the others, ascribed as susceptible (S). In addition, based on LD50, A. byzantina and A. sterilis had low susceptibility to glyphosate, with 604 and 458 g ae ha−1. Shikimic acid accumulation was able to discriminate between high susceptible (A. fatua (S)), low susceptible (A. byzantina and A. sterilis), and low resistant (A. fatua (R)) populations. On the other hand, the study revealed that A. fatua (R), A. byzantina and A. sterilis had low foliar uptake and decreased movement of glyphosate. In addition, the metabolism study showed less metabolite accumulation in A. byzantina and A. fatua (S). However, at 96 h after glyphosate application, A. fatua (R) and A. sterilis were able to convert more than 30% of glyphosate to aminomethylphosphonic acid (AMPA) and sarcosine. Enzyme basal activity and I50 values predicted high affinity between the herbicide and the target enzyme for all accessions, thus indicating that a target-site (TS) mechanism is probably not involved in the differences in glyphosate susceptibility. In closing, non-target site (NTS) mechanisms could participate both in A. fatua R to glyphosate, and low susceptibility in A. byzantina and A. sterilis from Spain.