University of California Division of Agriculture and Natural Resources

Clima y enfermedades causan la muerte de rboles en varias

Floods can have enhanced impacts when they occur in close succession with streamflow droughts. Despite the increased likelihood of impacts during such drought-to-flood transition events, substantial gaps remain in the understanding of the hydrological processes and drivers leading to their development. Specifically, it remains unclear how changes in hydrological conditions (IHCs) after drought and meteorological forcings during the transition towards flood conditions propagate to flood characteristics, such as duration and peak flow. We address this research gap by running three stress test experiments at the event scale: (1) changes in IHC based on perturbations applied to the meteorological forcing (e.g., temperature and precipitation) during the drought; (2) perturbation of observed forcing during the transition; and (3) modifications to both IHC and forcings during the event (i.e., a combination of cases 1 and 2). To do so, we calibrate the bucket-type GR4J hydrological model across a quasi-global dataset encompassing 2003 catchments. Using the results of all synthetic experiments conducted across all catchments, we estimate the isolated and joint sensitivities of both transition and flood characteristics to changes in drought characteristics (e.g., duration, intensity, severity) and to meteorological forcings during the transition. By analyzing the joint sensitivity of a given attribute (e.g., peak flow) to IHCs and meteorological forcings, we estimate the relative importance of each in driving the attribute's overall sensitivity (i.e., total effect of all individual sensitivities). Our findings indicate that, regardless of whether the system is stressed in isolation (i.e., experiment 1 or 2) or jointly (i.e., experiment 3), meteorological forcings - primarily temperature - are the main drivers affecting changes in transition and flood characteristics across hydroclimatic regions. Overall, clear differences between sensitivities, e.g., of peak flow to precipitation during the transition, emerge when comparing snowmelt- and rainfall-influenced catchments. Furthermore, hydroclimatic and streamflow regimes, along with catchment storage dynamics, are the main proxies for understanding the sensitivity of transition attributes to changes in IHC and meteorological forcings. Additionally, we show that IHCs are more important than meteorological forcing in explaining the variability of transition characteristics. Consequently, although IHCs control the baseline state, small changes in variables such as temperature during transitions can significantly alter flood characteristics, largely independently of the IHCs. Ultimately, we show that warming, rather than variations in drought severity (i.e., antecedent conditions) or precipitation, is likely to shape future transitional floods. Our results enhance our understanding of drought-to-flood transitions and their sensitivities to hydrometeorological conditions, thereby generating clearer insights into how droughts and meteorology influence floods and their impacts.

Abstract This exploratory study sought to determine the extent of implementing research ethics by animal scientists and how they contribute to improving research productivity in the global south. A cross-sectional survey design using stratified sampling was used. Data were collected from a sample of 93 scientists who had pursued bachelor’s, master’s, and/or doctoral degrees, or had conducted non-degree research. The study found imbalances by gender, with males pursuing research more than females ( p = 0.046 ). Surveys and experimental studies were conducted, rather than reviews ( p = 0001 ). There was limited acquisition of informed consent by researchers. No financial inducements were given to respondents. There was limited knowledge of the functions of institutional review boards; however, doctoral researchers had more knowledge than other categories ( p = 0.001 ). There were deliberate efforts to handle the cultures of respondents, such as hiring local enumerators. All researchers did not have conflicts of interest, and their funders never interfered with data management and reporting processes. However, the degree of study significantly ( p < 0.05 ) influenced the presence of several ethical issues, including guest authors, ghost authors, salami slicing, and bias in authorship assignment. The study recommends capacity building of animal scientists in ethical research processes with a focus on seeking informed consent, respondents' protection, and research ethics committees' roles. Universities should acquire anti-plagiarism software for researchers. Students and academics should build their capacity on ethical issues in publishing research results. Research Ethics Committees at universities should be strengthened to promote mainstreaming of research culture to foster credibility and usability of the findings in community development.

Phenological datasets for temperate fruit trees are often short, fragmented and geographically restricted, which hampers the development of cultivar-specific spring phenology models. To address this, we propose a novel calibration approach (“combined-fitting”), which pools observations from several cultivars of the same species, distinguishing between shared and cultivar-specific parameters. This method requires fewer observations per cultivar and allows jointly analyzing cultivars of the same species. We evaluate combined-fitting using the PhenoFlex framework, comparing it to a baseline model and to models that are fitted only with data for single cultivars (“cultivar-fit”). Our analysis is based on flowering data from nine almond, six apricot and six sweet cherry cultivars across Mediterranean (Spain, Morocco, Tunisia) and German climates. The combined-fit model failed to achieve higher prediction accuracy compared to the cultivar-fit and the baseline approach, as evidenced by similar root mean square errors across the data splits and calibration dataset sizes. When comparing the estimated parameters of the chill and heat accumulation submodels, we observed a large variation among cultivars of the same species in the cultivar-fit models. In contrast and by design, the combined-fit yielded only one parameter set for cultivars of the same species. Our findings demonstrate that integrating data from multiple cultivars can yield spring phenology models with high accuracy. Even though the combined-fit approach did not outperform the cultivar-fit approach, combined-fitting offers a practical solution for spring phenology modeling with limited datasets and facilitates comparison across cultivars of the same species.

Abstract This chapter analyzes bioeconomy strategies for decarbonization, emphasizing their importance in achieving global net-zero emissions by 2050. While renewable energy plays a central role in climate mitigation, it cannot alone eliminate fossil fuel dependence due to electrification limits, storage challenges, and sectoral constraints. Bioeconomy strategies complement renewables by leveraging biological systems to capture, substitute, and remove atmospheric CO₂. These strategies are organized into three pathways: photosynthesis, thermochemical conversion, and microbial processes. Together, they enable a diverse set of technologies—ranging from biofuels and bioplastics to soil carbon sequestration and carbon-negative systems like biochar and BECCS (Bioenergy with Carbon Capture and Storage). Strategies are further categorized into carbon sequestration, carbon substitution, and carbon removal approaches. Technology readiness varies across the portfolio. Afforestation, conventional biofuels, and bioplastics are commercially mature (TRL 9), while algae-based biofuels, microbial CO₂ conversion, and genetic engineering remain in earlier development stages. Economic feasibility also ranges widely. Nature-based solutions like afforestation offer highly cost-effective mitigation ($4.2–16.9/ton CO₂), whereas algae systems and some advanced biofuels are not yet competitive without policy support. Biochar and BECCS occupy a middle ground, offering scalable carbon removal with additional co-benefits for agriculture and energy systems. The chapter calls for targeted investments, policy alignment (e.g., carbon pricing), and regional implementation strategies to scale promising bioeconomy pathways. Emerging tools such as artificial intelligence and biotechnology can further accelerate progress. By delivering both carbon mitigation and broader sustainability outcomes, bioeconomy strategies represent essential components of an integrated, resilient, and low-carbon economic future.

Abstract Off-ground almond harvesting is a promising alternative to conventional on-ground methods, reducing dust, microbial contamination, and insect damage. However, the high moisture content (MC) in off-ground harvested almonds requires timely mechanical drying to maintain product quality and safety. This study aimed to characterize insect damage, physical and thermal properties of off-ground harvested almonds, and their components (hulls, shells, and kernels) at early (EH) and standard (SH) harvest stages, and to provide foundational data for drying process modeling and optimization. To minimize losses from prematurely detached almonds, EH was conducted 3–4 weeks before SH, which followed local practices. Off-ground harvesting reduced infestation by 52% compared to conventional methods, demonstrating significant quality and safety advantages. EH samples consisted entirely of in-hull almonds, while SH almonds included three distinct fractions: in-hull almonds, in-shell almonds, and loose hulls. EH almonds exhibited higher MC, thermal conductivity, and specific heat, indicating greater energy demand during drying. Among components, hulls had the highest MC and thermal properties, followed by shells and kernels. These findings support a two-phase drying strategy for EH almonds, starting with high temperature for efficient hull moisture removal, followed by moderate temperature to preserve kernel quality. In SH almonds, distinct thermal behaviors between in-hull and in-shell fractions, along with significant thickness differences (24.5 ± 2.5 mm vs. 17.2 ± 1.3 mm), highlight the need for separate drying. A size-based sorting strategy prior to drying is recommended to enhance efficiency and product uniformity. Overall, this study provides essential data to guide harvest-stage-specific postharvest practices in the almond industry.

Restoring populations of native keystone species can increase landscape resilience to global change when those species create or modify ecosystems. The North American beaver (Castor canadensis) is an ecosystem engineer that increases river water storage and residence time, increasing fire resilience at the landscape level. Beaver populations in North America are significantly lower than they were historically, but over the last decade, beavers have been increasingly recognized for their ecosystem services, and reintroduction efforts throughout their historic range have become more prevalent. Here, we modeled potential beaver dam‐building capacity, associated surface water storage, and fire resilience in California's Sierra Nevada, a region at high risk of drought and wildfire. We estimate that 51% of beaver dam‐building capacity remains in this region compared to historical levels, and considerable dam capacity remains in all watersheds. Our conservative estimates suggest that beaver dams have the potential to store a total of 120 million m3 of surface water and create 2200 km2 of fire resilience in high fire risk areas. Additionally, streams where beavers have the potential to create the greatest water and fire benefits due to physical landscape and habitat characteristics are frequently found within watersheds that are at high risk for both drought and fire. Specifically, we identified five priority watersheds that have both high risk for drought and fire impacts, and have high potential to benefit from beaver conservation and restoration. Even in areas where fire and drought are less probable, the reestablishment of beavers will likely provide similar benefits. This unique approach to quantifying potential beaver benefits illustrates that wildlife can increase resilience to global change stressors and suggests that biodiversity and nature‐based climate solutions are intertwined.