Southern Sierra Research Articles

Trends in regolith thickness in a headwater catchment, Sierra Nevada, California

AbstractRooting in deep regolith enables forests to withstand seasonal and annual precipitation shortfalls. Despite its ecological importance, spatial patterns in regolith thickness within forest ecosystems are scarcely documented. Regolith thickness was estimated at 66 sites throughout a 543‐ha watershed in the southern Sierra Nevada by hand auger to point of failure or a maximum depth of 7.5 m, describing a minimum thickness estimate. Regolith consists of 1–2 m of soil overlying thick and porous weathered granodiorite. Depth to auger failure ranged from 1.52 to an indeterminate depth beyond 7.5 m. A total of 27 points exceeded 7.5 m depth. Normal, lognormal, and gamma data distribution models were fitted to observations to extrapolate thickness across the watershed and estimate thicknesses beyond the measurement limitation. Predictions for the 95th percentile of regolith thickness varied substantially; 26.05 m for lognormal, 16.87 m for gamma, and 9.56 m for normal. Considering any best fit model, >55% of the watershed area was deeper than 5 m. Depth classes were formed to evaluate the extent to which topography is associated with spatial trends in regolith thickness. Spatial patterns were related to two covariate proxies (distance from stream channel and topographic wetness) with the general landscape trend of shallow depth classes (<3.3 m) in lowlands and deeper regolith classes (>7.5 m) in uplands. The normalized difference vegetation index signatures over the late stages of a 5‐year drought were greener in the lowlands. In contrast, upland forests displayed widespread tree die‐off, suggesting deep water storage does not maintain forests over long‐term drought.

Assessing Influence of HIV Status on Management outcomes of Drug Sensitive Pulmonary Tuberculosis in the Bo District of Southern Sierra Leone.

Purpose: Tuberculosis in Human immunodeficiency virus is a predictor of unfavourable outcome during the management of TB cases due to the synergy both bear in the patient. This study is to test the hypothesis that patient is more likely to be unfavourable in the co infected than the TB stand-alone patients with standard treatment in patients. The associated factors might not be exhaustive that leads to outcomes factored in the study.
 Methodology: The retrospective cohort study data of 1,947 patients admitted from 1st January 2020 to 1st January 2022 at TB treatment centres in Bo district of Sierra Leone was analysed using datatab software after data completeness was checked and cleaned. Both bi-variable and multi-variable logistics regression and other statistical methods were employed to assess the relationship between HIV+TB synergic as well as TB alone outcomes. Data was analysed based on 95% CI and p<0.05.
 Findings: When an ANOVA was used to test for significance from zero, F=3.41, p = 0.002, R2 = 0.01. Regression coefficients for exits = 1.17 - 0.02., gender =-0.02, literacy = -0.1, family bread winner with TB= -0.02 and foods insecurity = +0.07. A point-biserial correlation was also computed to determine the relationship between HIV status and TB interms of outcome which showed a positive correlation between HIV status and exit code information, although no statistically significance (rpb = 0.04, n = 1987, p = .065).
 Unique contribution to theory, practice and policy: Successful treatment outcome was high among HIV/TB co-infected as well as TB mono-infected should both be treated with standard treatments. Strengthening patient management in a collaborative approach and use of novel drugs as well as research will increase the survival rate of patients treated. With standard treatment and patient centered care the outcome of TB patient management will not be hinged on their HIV status. The adoption of this theory into policy in TB programmes will improve the success rate in TB management.

Cenozoic slip along the southern Sierra Nevada normal fault, California (USA): A long-lived stable western boundary of the Basin and Range

AbstractThe uplift history of the Sierra Nevada, California, is a topic of long-standing disagreement with much of it centered on the timing and nature of slip along the range-bounding normal fault along the east flank of the southern Sierra Nevada. The history of normal fault slip is important for characterizing the uplift history of the Sierra Nevada, as well as for characterizing the geologic and geodynamic factors that drove, and continue to drive, normal faulting. To address these issues, we completed new structural studies and extensive apatite (U-Th)/He (AHe) thermochronometry on samples collected from three vertical transects in the footwall to the east-dipping southern Sierra Nevada normal fault (SNNF). Our structural studies on bedrock fault planes show that the SNNF is a steeply (~70°) east-dipping normal fault. The new AHe data reveal two elevation-invariant AHe age arrays, indicative of two distinct periods of cooling and exhumation, which we interpret as initiation of normal faulting along the SNNF at ca. 28–27 Ma with a second phase of normal faulting at ca. 17–13 Ma. We argue that beginning in the late Oligocene, the SNNF marked the now long-standing stable western limit, or breakaway zone, of the Basin and Range. Slip along SNNF, and the associated unloading of the footwall, likely resulted in two periods of uplift of Sierra Nevada during the late Cenozoic. Trench retreat, driven by westward motion of the North American plate, along the Farallon–North American subduction zone boundary, as well as the gravitationally unstable northern and southern Basin and Range pushing on the cold Sierra Nevada, likely drove the late Oligoceneaged normal slip along the SNNF and the similar-aged but generally local and minor extension within the Basin and Range. We posit that the thick proto–Basin and Range lithosphere was primed for late Oligocene extension by replacement of the steepening Farallon slab with hot and buoyant asthenosphere. While steepening of the Farallon slab had not yet reached the southern Sierra Nevada by late Oligocene time, we speculate that late Oligocene slip along the SNNF reactivated a late Cretaceous dextral shear zone as the Sierra Nevada block was pulled and pushed westward in response to trench retreat and gravitational potential energy. The dominant middle Miocene normal faultslip history along the SNNF is contemporaneous with high-magnitude slip recorded along range-bounding normal faults across the Basin and Range, including the east-adjacent Inyo and White mountains, indicating that this period of extension was a major regional tectonic event. We infer that a combination of slabdriven trench retreat along the Juan de Fuca–North America subduction zone boundary and clockwise rotation of the southern ancestral Cascade Range superimposed on continental lithosphere preconditioned for extension drove this episode of middle Miocene normal slip along the SNNF and extension to the east across the Basin and Range. Transtensional plate motion along the Pacific–North America plate boundary, and likely a growing slab window, continued to drive extension along the SNNF and the western Basin and Range, but not until ca. 11 Ma when the Mendocino triple junction reached the latitude of our northernmost (U-Th)/He transect.

Threshold controlling runoff generation mechanisms in Mediterranean headwater catchments

Runoff generation thresholds and pathways are critical to understanding catchment-scale hydrological processes. The variability in catchment storage, soil moisture dynamics, and rainfall characteristics influence the spatial and temporal variability of runoff thresholds and pathways. This study used six years of hourly hydro-meteorological datasets of two independent (P301 and P303) and one nested (P300) headwater catchments located in the southern Sierra Nevada region of California, USA, to understand the spatial variability in runoff thresholds and runoff pathways. Further, we identified the spatio-temporal variability in preferential flow pathways, changes in soil moisture, and vertical wetting front velocity along with their controlling factors. From the analysis of 129 rainfall-runoff events, it was found that the catchment runoff was activated when the catchment wetness (i.e., storage plus rainfall) was greater than 212 mm, 238 mm, and 250 mm in P301, P303, and P300, respectively. The catchment storage was higher at the lower slope, resulting in higher runoff thresholds, compared to upslope locations inside P301 and P303. Further, we observed dominance of preferential flow (> 60%) at 60 cm and 90 cm depth at the lower and upper slope locations, respectively, indicating a domination of subsurface runoff generation mechanism in these catchments. The preferential flows were more frequent during the drought years (2012–2015) than those in the normal years (2010–2011). Furthermore, we observed higher vertical wetting front velocity at deeper depths, but no consistent pattern was observed in the change in soil moisture along the soil profile. This study will be useful for field hydrologists and modelers to design an experimental setup and to develop a more realistic hydrological model considering the spatio-temporal variation in runoff thresholds and preferential flow pathways in forested montane headwater catchments of the Mediterranean region.

An Analysis of the Grammatical Errors in the Written English Compositions of JSS 1 Pupils in Five Junior Secondary Schools in Bo City, Southern Sierra Leone

This study focuses on the grammatical errors in the essays written by JSS1 pupils in five junior secondary schools in Bo city. It aims at identifying the errors occurring in the use English grammar by pupils, classifying the errors, determining their frequency levels and their sources. The descriptive survey design was used in this study, where out of a population of 853 pupils, 250 pupils were used a sample for this study. Each of the pupils was asked to write an essay, and the scripts were marked to identify all grammatical errors made by the pupils. From this study, it was discovered that out of 250 scripts, 32% of the pupils were not able to communicate their thoughts meaningfully. Out of the comprehensible scripts the following errors were identified and their frequencies: wrong use of tense 29.54%, errors in spelling 24.67%, errors in the choice of words 13.13%, wrong use of prepositions 7.79%, verb addition errors 5.84%, preposition addition errors 4.87%, pronoun addition, subject-verb agreement errors, wrong use of pronouns, plural and verb omission errors all received 1.62% each. The study further revealed that a good number of errors discovered from students’ writings were intralingual errors.

Shifts in fisher (Pekania pennanti) diet in response to climate-induced tree mortality in California assessed with DNA metabarcoding

A recent climate-induced tree mortality event in California, USA has led to dramatic landscape-level changes in the southern Sierra Nevada. Wide-spread conifer mortality was documented in habitat occupied by fisher (Pekania pennanti), a mature-forest associated species of conservation concern in this region. We analyzed fisher scats collected on the Sierra National Forest from the pre-tree-mortality period (PreTM, 2011 – 2013) and post-tree-mortality period (PostTM, 2017 – 2018). We used DNA metabarcoding to successfully identify taxa and summarized diet composition for 109 PreTM and 102 PostTM fisher scats. We observed 48 different diet items (33 assigned to species and 15 to genus). Mammals, birds, and plants of the Ribes genus (gooseberries and currents) comprised the highest proportions of diet items, although scats also contained DNA from reptiles, insects, arachnids, snails, and fungi. The frequency of occurrence of mammalian prey items was lower in PostTM (49.0%) versus PreTM scats (81.7%) with a reduction in the occurrence of two tree squirrels (Douglas squirrel and Humboldt’s flying squirrel). A higher proportion of scats collected PostTM (46.1%) contained DNA from Ribes spp. versus scats collected PreTM (19.3%). Our data reveal potential cascading effects of climate-induced tree mortality on fisher diet in the southern Sierra Nevada. Flexibility in fisher diet, however, may allow resilience to ecological change though future studies should consider the behavioral, energetic, demographic or fitness consequences from a shift away from medium-sized mammalian prey to plants.

A Remote Sensing and GIS Analysis of Rockfall Distributions from the 5 July 2019 Ridgecrest (MW7.1) and 24 June 2020 Owens Lake (MW5.8) Earthquakes

We examine the coseismic influence of the 5 July 2019, MW7.1 Ridgecrest and the 24 June 2020 MW5.8 Owens Lake earthquakes on rockfall distributions in two undisturbed high-altitude areas of the southern Sierra Nevada Mountains, California, USA. These events occurred within the geologically recent (<2 Mya) Walker Lane/eastern California shear zone. While both study areas are characterized as plutonic, the Owens Lake event largely affected terrain that was formerly glaciated and oversteepened while the Ridgecrest event affected non-glaciated terrain. Our inventory of rockfall locations was derived from analysis of Sentinel-2 images acquired just prior to and immediately after the events. This difference mapping approach using readily-available Sentinel-2 imagery allows for rapid rockfall and landslide mapping. GIS analysis shows that even though the total area assessed for both earthquakes was similar (~1500 km2), the significantly lower magnitude Owens Lake event produced nearly twice as many (102) mappable rockslides as the significantly stronger Ridgecrest event (58), a difference likely due to slope oversteepening in the formerly glaciated area. Significant seismic amplification by topography and reactivation of preexisting failures was apparent for both areas. Inclusion of these factors may improve failure predictions and rockfall probability estimation.

Priority areas for the conservation of the genus Abies Mill. (Pinaceae) in North America

Fir forests (Abies, Pinaceae) are dominant in temperate regions of North America; however, they have experienced high degradation rates that can threaten their long-term continuity. This study aimed to identify the priority areas for the conservation of the genus Abies in North America. First, we modeled the species distribution of the 17 native species through ecological niche modeling, considering 21 environmental variables. Then, we defined the priority areas through multi-criteria analysis, considering the species richness, geographic rareness, irreplaceability, habitat degradation, and risk extinction. We also built six scenarios, giving more priority to each criterion. Finally, we identified the proportion of the extent of the priority areas covered by protected areas. Elevation, precipitation seasonality, and winter precipitation influenced the distribution of most of the Abies species. When considering equal weights to each criterion, the priority areas summed up 6% of the total extent covered by the Abies species in North America. Most priority areas were located on the West Coast of the United States, the Eastern Sierra Madre, Southern Sierra Madre, Sierras of Chiapas and Central America, and the Trans-Mexican Volcanic Belt ecoregions. In these ecoregions, the Abies species are restricted to small areas facing high degradation levels. Only 16% of the area covered by the Abies species in North America is protected, mainly under restrictive schemes such as National Parks and Wilderness Areas. The priority areas identified could be the basis for establishing or enlarging protected areas. The preservation of the genus Abies could also maintain other ecological features and processes such as biodiversity, forest resources, and environmental services.

PHILONOTIS BREUTELIOIDES (BARTRAMIACEAE, BRYOPHYTA), A NEW MONTANE FEN MOSS SPECIES ENDEMIC TO CALIFORNIA

Philonotis breutelioides Shevock & Aguero is described as a new endemic moss species restricted to montane and subalpine fen habitats in California from the southern Cascades and Klamath Range south to the southern Sierra Nevada. Molecular data suggests an affinity within the genus Philonotis even though this new species shares morphological character states more frequently observed in the genus Breutelia. Available molecular data suggest distinctiveness of the new species within Philonotis fontana lineage, but they are insufficient to resolve relationships among the taxa in this lineage. Morphologically, Philonotis breutelioides differs from P. fontana by having more narrowly tapered leaves with slightly flexuose apices, leaf base with obvious plications, and elongate thin-walled cells in more numerous rows between costa and margin.

Re:]Entanglements: Colonial Collections in Decolonial Times curated by Paul Basu

Re:]Entanglements: Colonial Collections in Decolonial Times curated by Paul Basu

Prevalence and Associated Risk Factors of Hookworm Infection among Primary School Children in Three Selected Schools in Moriba Town, Southern Sierra Leone

Background: In tropical and subtropical developing nations, hookworm is the main cause of maternal and childhood illnesses. In vulnerable children, hookworm causes cognitive and growth retardation, intrauterine growth delay, prematurity, and low birth weight among newborns of infected mothers. The research aims to determine the prevalence and risk factors of hookworm infection among primary school children in three selected schools in the study area. Methods: This study utilized a case-control research approach. Stool specimens were collected and analyzed for intestinal parasites from children in classes 1-6. A total of sixty (60) enrolled students between the ages of 5 and 15 were chosen at random from three primary schools in Moriba town, Bo city, southern Sierra Leone. Results: The research findings revealed that the prevalence of hookworm infection was 47.4% among 5-7 years in the study area. The findings also demonstrated that there was no connection between the children’s sex and hookworm infection. It was discovered that women had a higher risk of contracting an infection than men. The prevalence of hookworm among the children and the accessibility of toilets in the home were significantly correlated. A significant association with hookworm infection was shown in the toilet facility type. Conclusion: Hookworm infections are extremely frequent in Sierra Leone among schoolchildren and are a major cause of the disease. Poor personal and environmental hygiene, poverty, and a favourable climate are important variables for the sustainability of transmission, but no policy-driven effort to prevent it has been made.

Repeated burns fail to restore pine regeneration to the natural range of variability in a Sierra Nevada mixed‐conifer forest, U.S.A.

Fire‐exclusion has acted as a major perturbation on dry conifer forests in the western United States, increasing tree density and, in mixed‐conifer forests, the dominance of shade‐tolerant species. Restoration efforts aim to reverse these effects by reducing stand density, restoring relative proportions of tree species, and reintroducing recurrent fire, but there are limited long‐term data on the effects of repeated burning on tree regeneration. We analyzed two decades of seedling and overstory data from the Teakettle Experimental Forest in the southern Sierra Nevada, California, United States to determine how thinning and repeated burning affect seedling establishment and overstory recruitment. Across treatments, pine seedling densities remained much lower than shade‐tolerant seedling densities. We found repeated burns led to modest increases in sugar pine (Pinus lambertiana) and substantial increases in incense‐cedar (Calocedrus decurrens) seedling densities 4 years postburn. No significant differences in seedling densities among repeated burning treatments were detected for Jeffrey pine (P. jeffreyi) or white fir (Abies concolor). Estimates of natural midstory recruitment were much higher among white fir and incense‐cedar than pines, even following treatments. However, postharvest planting increased rates of pine midstory recruitment in overstory thinned treatments. Our results suggest that fire‐exclusion may have shifted the ecosystem out of its initial domain of attraction, creating a forest dominated by shade‐tolerant species that exhibits hysteresis by resisting a return to a natural range of variability even after restoring structure and process. Planting pine species may be effective at overcoming this resistance to restore the forest to a pine‐dominated state.

Challenges in Developing Aquaculture for Livelihood Enhancement in Bo City, Southern Sierra Leone

The study investigated socioeconomic characteristics, aquacultural practices and constraints among smallholder fish farmers in the study location of Bo City, Southern Sierra Leone. The present study employed a survey research design. The smallholder farmers who were growing food for themselves, for sale, and for consumption by others as well as those who were primarily growing it for the market were each given 40 questionnaires in total. The results revealed that most of the respondents were male (90.0%), married (60.0%), lacked training in fish farming (57.5%) and the household income of most (60.0%) ranged from NLe600-NLe1,000. The farmers mostly opined low fish farming experience (70.0%), Semi-intensive fish farming (67.5%), low aquaculture development (57.5%), predominantly seasonal fish pond irrigation (77.5%). All of the respondents’ view fish farming as an economically viable enterprise as well as a profitable (87.5%) entity. The mean rank of constraints was significantly (p ≤ 0.006) differed among fish farmers. The key fish farming constraints included culturing fish, fish feed in culturing fish, less interest, fewer fish farmers, high inputs, high cost of fish pond construction and intensive capital investment that could be exploited for improved productivity. The outcomes of these recent studies imply that fish farmers should receive training and funding for their operations to improve their competitiveness in their smallholder fish businesses as well as in the local and international aquaculture industries. Also, the governments and other practitioner authorities ought to implement policies and initiatives that would support fish farming activities, further research development in aquaculture, the development of the nation, and the fish farmers themselves.

Ecological integrity of whitebark pine ecosystems in California’s national forests

Whitebark pine ( Pinus albicaulis) forest ecosystems in California are diverse and unique, yet their current status and condition are uncertain. Using a combination of geospatial and field plot data, we assessed patterns in the structure, composition, and health of whitebark pine ecosystems on national forests throughout the state of California to evaluate potential signs of declining ecosystem integrity. We found whitebark pine ecosystems to be structurally, compositionally, and functionally distinct among subregions of California, and all subregions displayed some evidence of declining ecological integrity. Whitebark pine forests in northern California exhibited signs of greater stand densification (Cascade–Klamath), potential encroachment by shade-tolerant conifer species (Cascade–Klamath and Warner Mountains), and increased tree mortality associated with mountain pine beetle outbreaks (Warner Mountains) than elsewhere in California. Whitebark pine stands in the Sierra Nevada showed signs of stand densification (central Sierra) and localized mountain pine beetle outbreaks (southern Sierra east). Notwithstanding these negative signs, much of the state’s whitebark pine ecosystems on national forestlands appear to be relatively healthy and intact compared to more northern latitudes. Active management may be required to restore whitebark pine ecosystems on national forests in California with declining integrity, including stands experiencing substantial stand densification, encroachment by shade-tolerant conifers, and mountain pine beetle outbreaks.

The Sierra Nevada (California) Is a Relict Tropical Late Cretaceous Range: A Field Guide to the Evidence

ABSTRACT: The notion of late-Cenozoic uplift was implied in 1865 by Whitney, who assumed a buried bedrock canyon lay beneath the Table Mountain latite flow and above the modern Stanislaus River canyon, with the difference between the two longitudinal profiles suggesting post-latite uplift. However, only a series of buried bedrock ridges exists and no uplift is inferred. I briefly present thirty-three key sites of about three hundred remnants in the entire Sierra Nevada, from north of the Feather River south to the Kern River. These include Late Cretaceous strata, Eocene strata, Oligocene rhyolites, Mio-Pliocene andesites, and Quaternary basalts, some remnants on canyon floors but most on lower slopes, preserving topography at the time of deposition. I found no evidence of late-Cenozoic incision, which is required under the late-Cenozoic uplift paradigm. Instead, each site contains verifiable field evidence that challenges the uplift paradigm. Moreover, the results are consistent with the range having a common uplift history: the crest elevation, drainage topography, and relief developed in the Late Cretaceous, and only minor changes occurred in post-Eocene time. This supports uplift studies in the northern Sierra based on hydrogen and oxygen isotopes on auriferous deposits, and supports pediment ages of 40+ Ma in the southern Sierra. Uplift studies based on thermochronology and numerical modeling, on cave-sediment dating and its implied incision, and on significant denudation on benchlands cannot be reconciled with verifiable field evidence. Finally, migration of giant sequoias southwest into the Sierra Nevada was possible only from late in the Cretaceous, when the Nevadaplano came into existence and the range was high, negating any Sierran late-Cenozoic uplift paradigm.

AN EMPIRICAL AND ECONOMIC ANALYSIS OF CASSAVA PRODUCTIVITY IN SELECTED AREAS OF SOUTHERN SIERRA LEONE

This study examined the productivity and economic analyses of the cassava production in three communities—Nyallay, Sammamie, and Sindeh sections in Bo districts, Southern Sierra Leone. The crop is processed into garri, fufu, akara, and other foods. Cassava can also be used to make flour, pellets, and chips for animal consumption, as well as biofuel and particle boards The data was gathered using a questionnaire and interview schedule that were both well organized. Descriptive statistics, financial techniques, and a multiple regression model were all employed in the data analysis. The main data came from a sample of 300 cassava growers from three regions. The collected data were evaluated using econometric regression analysis. The findings indicated that, the net farm income was Le 214,361 and the net return on investment was almost Le 258, 375. The findings of a regression analysis showed that the number of cassava cuttings, hired labor, farm size, farming experience, and age statistically substantially influenced the output of cassava in the research region. It is indicated that the availability of improved cassava cuttings in the area and farmers’ access to subsidized inputs like fertilizer. In the study it was suggested that farmers be prodded to invest in the cultivation of cassava because of its economic worth and profitability. Cassava growers should be encouraged to obtain instruction on correct agronomic practices and input usage, and inputs should be made available and at reasonable costs, especially improved types of cassava cuttings, this will increase productivity.

Cassava Groundnut Intercropping: A Sustainable Land Management Practice for Increasing Crop Productivity and Organic Carbon Stock on Smallholder Farms

Cassava-groundnut intercropping is not a common practice among smallholder farmers in Sierra Leone even though both crops are well suited for intercropping. On-farm trials were conducted in three locations (Bai Largor, Bassah, and Njala Kanima) in the Moyamba district during the 2021 cropping season to investigate the efficacy of cassava-groundnut intercropping for increasing crop productivity and soil organic carbon stock on smallholder farms in the Moyamba district, Southern Sierra Leone. The experimental design was a randomized complete block design in three replications with treatments of sole groundnut, sole cassava and cassava-groundnut intercropping. Data on the yield and yield components of cassava and groundnut were analysed using the PROC MIXED procedure of SAS 9.4 and means were compared using the standard error of difference (SED). The above-ground biomass, number of roots per plant, and fresh root yield of cassava were not significantly (p > 0.05) affected by the cassava-based cropping system. Averaged across locations, intercropping cassava with groundnut decreased the above-ground biomass, the number of roots per plant, and fresh root yield of cassava by 17%, 11%, and 17%, respectively. The above-ground biomass, number of pods per plant and fresh pod yield of groundnut were significantly (p 1), the highest net revenue and benefit-cost ratio. The benefit-cost ratio was also favourable for the sole cassava (BCR > 1) but not favourable for the sole groundnut (BCR < 1). Averaged across locations, intercropping cassava with groundnut increased the benefit-cost ratio by 121% and 13% when compared to the sole groundnut and sole cassava. In the event of a 40% yield loss for the cassava and groundnut, the benefit-cost ratio was favourable (1.12) only for the cassava groundnut intercropping system. The net soil organic carbon stock was favourable only for the cassava-groundnut intercrop. Averaged across locations, the net soil organic carbon for the cassava-groundnut intercropping increased by 3.4% when compared to the baseline within one cropping cycle of the cassava (12 months). The results confirm that cassava-groundnut intercropping is a sustainable land management practice that could enhance crop productivity and soil organic carbon stock on smallholder farms.

Changes in Rainfall and Temperature and Its Impact on Crop Production in Moyamba District, Southern Sierra Leone

Rainfall and temperature are the important variables that are often used to trace climate variability and change. A Perception study and analysis of climatic data were conducted to assess the changes in rainfall and temperature and their impact on crop production in Moyamba district, Sierra Leone. For the perception study, 400 farmers were randomly selected from Farmer-Based Organizations (FBOs) in 4 chiefdoms and 30 Agricultural Extension Workers (AWEs) in the Moyamba district were purposely selected as respondents. Descriptive statistics and Kendall’s test of concordance was used to analyze the data collected from the farmers and AEWs. Data for the analysis of variability and trends of rainfall and temperature from 1991 to 2020 were obtained from the Sierra Leone Meteorological Agency and Njala University and grouped into monthly, seasonal and annual time series. Regression analyses were used to determine the statistical values and trend lines for the seasonal and annual time series data. The Mann-Kendall test and Sen’s Slope Estimator were used to analyze the significance and magnitude of the trends respectively. The results of both studies show evidence of climate change in the Moyamba district. A substantial number of farmers and AEWs perceived a decrease in the annual rainfall amount, length of the rainy season, a late start and end of the rainy season, an increase in the temperature during the day and night, and a shortened harmattan period over the last 30 years. Analysis of the meteorological data shows evidence of variability in the seasonal and annual distribution of rainfall and temperature, a decreasing and non-significant trend in the rainy season and annual rainfall and an increasing and significant trend in seasonal and annual temperature from 1991 to 2020. However, the observed changes in rainfall and temperature by the farmers and AEWs partially agree with the results of the analyzed meteorological data. The majority of the farmers perceived that; adverse weather conditions have negatively affected crop production in the district. Droughts, high temperatures, and irregular rainfall are the three major adverse weather events that farmers perceived to have contributed to a substantial loss in the yields of the major crops cultivated in the district. In response to the negative effects of adverse weather events, a substantial number of farmers take no action due to their lack of knowledge, technical or financial capacity to implement climate-sensitive agricultural (CSA) practices. Even though few farmers are practicing some CSA practices on their farms, there is an urgent need to build the capacity of farmers and AEWs to adapt to and mitigate the negative impacts of climate change. The most priority support needed by farmers is the provision of climate-resilient crop varieties whilst the AEWs need training on CSA practices.

Preliminary Analysis of Unsaturated Fatty Acid Profiles of Coffea arabica L., in Samples with a Denomination of Origin and Speciality of Oaxaca, Mexico.

In February 2020, Coffea arabica L. grown on the coast and in the Southern Sierra Madre of the state of Oaxaca, Mexico obtained the denomination of origin. Which does not have data on color and chemical composition, the first associated with the degree of roasting and the second with lipids (17-18%), as the group of compounds responsible, in part, for flavor, consistency, and may contribute to health benefits. In the present work, color was determined on the CIE L*a*b* scale and the unsaturated fatty acids by Nuclear Magnetic Resonance (NMR) of 1H and 13C in samples of medium roasted specialty coffee from the "Pluma" coffee-growing region, Oaxaca, Mexico. The average value of L* luminosity in ground coffee was 42.1 ± 0.1 reported for a light roast. Unsaturated fatty acids were quantified from the lipid fraction of the gr1 ound grain by NMR 1H and 13C, obtaining on average the highest abundance of linoleic (41.7 ± 0.5 by 1 H and 41.24 ± 0.5 by 13C), followed by oleic (9.2 ± 0.2 by 1H and 7.4 ± 0.2 by 13C) and linolenic (1.5 ± 0.1 by H and 1.1 ± 0.2 by 13C). This study indicates that 1H and 13C NMR spectroscopy is a useful tool for the quantification of linolenic, linoleic, and oleic fatty acids by the method of key signal shifts of these acids found in lipid samples in roasted coffee grains.

A Vascular Flora of the South Fork Tule River, Southern Sierra Nevada, Tulare County, California

A Vascular Flora of the South Fork Tule River, Southern Sierra Nevada, Tulare County, California