Valley Sites Research Articles

Analysis of site-response residuals from empirical ground-motion models to account for observed sedimentary basin effects in Wellington, New Zealand

Analysis of prediction–observation residuals from the empirical ground-motion models (GMMs) used in the 2022 New Zealand National Seismic Hazard Model (NZ NSHM) update indicates a general underprediction of ground motions in the period range of [Formula: see text] s for soft sedimentary basin sites in Wellington. This study uses residual analysis to quantify this underprediction, understand the spatial distribution of these residuals and the specific conditions that cause them, and investigate options for the development of non-ergodic site-response adjustments to the GMMs. All 15 GMMs used in the NZ NSHM were evaluated, and the variability in site-response residuals between different models and different tectonic types of earthquake sources was quantified. Sites are regionalized based on different geomorphic features, such as individual basins and valleys. For example, average site terms are calculated for Te Aro, Thorndon, Miramar, Lower Hutt, Upper Hutt, and several smaller valleys. The period at which maximum underprediction occurs at these sedimentary basin and valley sites was found to correlate well with the fundamental site period of the soil profile [Formula: see text], suggesting improvements can be made to regionalized GMMs by incorporating site period into the site-response prediction for sedimentary basin sites.

Transfer Efficiency and Organization in Turbulent Transport over Alpine Tundra

The exchange of momentum, heat and trace gases between atmosphere and surface is mainly controlled by turbulent fluxes. Turbulent mixing is usually parametrized using Monin–Obukhov similarity theory (MOST), which was derived for steady turbulence over homogeneous and flat surfaces, but is nevertheless routinely applied to unsteady turbulence over non-homogeneous surfaces. We study four years of eddy-covariance measurements at a highly heterogeneous alpine valley site in Finse, Norway, to gain insights into the validity of MOST, the turbulent transport mechanisms and the contributing coherent structures. The site exhibits a bimodal topography-following flux footprint, with the two dominant wind sectors characterized by organized and strongly negative momentum flux, but different anisotropy and contributions of submeso-scale motions, leading to a failure of eddy-diffusivity closures and different transfer efficiencies for different scalars. The quadrant analysis of the momentum flux reveals that under stable conditions sweeps transport more momentum than the more frequently occurring ejections, while the opposite is observed under unstable stratification. From quadrant analysis, we derive the ratio of the amount of disorganized to organized structures, that we refer to as organization ratio (OR). We find an invertible relation between transfer efficiency and corresponding organization ratio with an algebraic sigmoid function. The organization ratio further explains the scatter around scaling functions used in MOST and thus indicates that coherent structures modify MOST. Our results highlight the critical role of coherent structures in turbulent transport in heterogeneous tundra environments and may help to find new parametrizations for numerical weather prediction or climate models.

Patterns of pastoralism: Temporal and regional variation within the Indus Valley Civilisation

The archaeozoological study of the Indus Valley Civilisation, particularly in the last few decades, has resulted in a better understanding of human-animal interactions, providing information about species that have been commonly found at Indus Valley sites, both wild and domestic. This is also indicative of the nature of animal-based subsistence at these settlements and the interplay between humans, animals, and the environment. However, these studies have largely been conducted at the level of individual sites, and despite extensive analysis of excavated faunal materials, synthesis of faunal data across different developmental phases of this civilisation and its regions, has rarely taken place. As a result, there exists little understanding of broader animal utilisation patterns within the Indus Valley Civilisation and their relation to climate and landscape. This article produces a comparative analysis of domestic animal utilisation by combining and reanalysing faunal data from different regions of the Indus Valley Civilisation. Our analysis reveals extreme disparity in the spatial and temporal distribution of domesticated animals within this Civilisation. Of the different regions, the amount of data required for interpretation is only available from Haryana and Gujarat, and this largely pertains to the Mature Harappan period, with the Early and Late Harappan phases being grossly underrepresented. Although cattle, buffalo, goats, sheep, and pigs were the primary domesticates across regions, their distribution and economic importance varied and changed over time. This variation may indicate differentiated regional and temporal cultures and adaptations to climatic change.

Trincheras Tradition Plant Use Practices from ∼400 to 1450 CE

The Trincheras tradition thrived in the Altar, Magdalena, and Asunción-Concepción valleys from 400 to 1450 CE. In the early twentieth century, archaeologists proposed that the Trincheras people were hunter-gatherers until around 1300 CE. This study investigates whether the plant use practices of the Trincheras tradition remained consistent across different regions and through time. I compare archaeological and macrobotanical data recovered at three Altar Valley Trincheras sites dated to ∼750–1300 CE (El Póporo, La Potranca, and San Martin) and integrate data from La Playa (400–650 CE) and Cerro de Trincheras (1300–1450 CE). The results revealed that the Trinchereños were agriculturalists from 400 to 1450 CE, disproving twentieth-century archaeologists' hypothesis. Between 1050 and 1300 CE, the ubiquity values of maize were the greatest at Trincheras Altar Valley sites. However, after relocating to the Magdalena Valley around 1300 CE, the percent presence of maize decreased, while that of agave and foraged foods increased.

Langke Bulawa Statue in the perspective of review Bada valley site culture

Langke Bulawa Statue in the perspective of review Bada valley site culture

Unstructured satellite survey detects up to 20% of archaeological sites in coastal valleys of southern Peru.

Satellite survey is widely used for archaeological site discovery, but the efficacy of the method has received little systematic investigation. In this analysis, twelve study participants of different experience levels performed an unstructured remote survey of 197 km2 in the Sama and Moquegua valleys of south central Peru where previous pedestrian surveys recorded 546 archaeological sites. Results indicate an average site discovery rate of 9.3% (0-18%, 95% range). The most experienced participants detect up to 20% (17-22%) of known archaeological sites. These detection rates can be used to derive reliable site frequency estimates on the Andean coast, which can be used in planning and budgeting for field efforts and estimating demographic patterns at large spatial scales that are difficult to achieve through pedestrian survey. More generally, this analysis offers a method for deriving correction terms specific to other parts of the world. Additionally, the results can serve as a baseline for evaluating the effectiveness of emerging artificial intelligence routines for archaeological site detection.

Prokaryote communities along a source-to-estuary river continuum in the Brazilian Atlantic Forest.

The activities of microbiomes in river sediments play an important role in sustaining ecosystem functions by driving many biogeochemical cycles. However, river ecosystems are frequently affected by anthropogenic activities, which may lead to microbial biodiversity loss and/or changes in ecosystem functions and related services. While parts of the Atlantic Forest biome stretching along much of the eastern coast of South America are protected by governmental conservation efforts, an estimated 89% of these areas in Brazil are under threat. This adds urgency to the characterization of prokaryotic communities in this vast and highly diverse biome. Here, we present prokaryotic sediment communities in the tropical Juliana River system at three sites, an upstream site near the river source in the mountains (Source) to a site in the middle reaches (Valley) and an estuarine site near the urban center of Ituberá (Mangrove). The diversity and composition of the communities were compared at these sites, along with environmental conditions, the former by using qualitative and quantitative analyses of 16S rRNA gene amplicons. While the communities included distinct populations at each site, a suite of core taxa accounted for the majority of the populations at all sites. Prokaryote diversity was highest in the sediments of the Mangrove site and lowest at the Valley site. The highest number of genera exclusive to a given site was found at the Source site, followed by the Mangrove site, which contained some archaeal genera not present at the freshwater sites. Copper (Cu) concentrations were related to differences in communities among sites, but none of the other environmental factors we determined was found to have a significant influence. This may be partly due to an urban imprint on the Mangrove site by providing organic carbon and nutrients via domestic effluents.

The Impact of Circuits and Systems on the Etna Valley Site [CAS Regional Report

The Impact of Circuits and Systems on the Etna Valley Site [CAS Regional Report

The transformation of river ecosystems caused by mining affects bird breeding in indigenous riparian habitats

Our study considered the excavation of sand and gravel, which modifies the landscapes of riparian ecosystems. It promotes the creation of water bodies with surrounding vegetation, but it also results in the loss of natural habitats.We investigated the species richness, composition, and abundance of aquatic and terrestrial breeding birds and their interaction with three habitat types: managed and abandoned flooded pits, and oxbow lakes. We surveyed 117 sites in medium-sized river valleys in the foreground of the Bohemian Massif (Czech Republic), and in the Carpathian Mountains (Poland, Slovakia) in 2022.Flooded pits were suitable for open-water and colonial birds. Managed flooded pits were also suitable for early successional land birds, but they did not provide habitat for birds that use marshes and wet meadows, or riparian woodlands. The majority of species preferred to breed in oxbow lakes with riparian forests and these areas hosted the highest number of threatened species.We concluded that high levels of disturbance in riparian ecosystems promoted some birds (e.g. colonial or breeding in early-successional habitats), but it negatively affected the overall bird diversity, and it led to a species composition shift with the elimination of taxa associated with indigenous riparian habitats. The importance of flooded pits increases with subsequent plant succession. Our results indicate that gravel or sand mine pits, although beneficial for some taxa, are not substitutes for natural habitats in riparian ecosystems, as they do not support birds breeding in indigenous riparian habitats. Natural oxbow lakes with riparian forests are habitats that need to be preserved to effectively promote local biodiversity.

Fish Symbolism in Indus Valley Epigraphy and Protohistoric Accounts

The contribution of the Indus Valley civilization to the historic cultures of South Asia is a matter of debate due to a discontinuity in material culture, from the time of its decline to the reappearance of urbanization several centuries later. Progress in the epigraphy of the Indus Valley has been hindered by the absence of a bilingual inscription and the brevity of its texts. One of the most frequent signs encountered in its undeciphered writing system is the pictogram of ‘fish’. On a few seal inscriptions, this sign appears alone, suggesting that it represented a meaningful word or a name. It is noteworthy that Indian literature of later centuries recounts a protohistoric kingdom named Matsya in the vicinity of the Indus Valley sites, as matsya is the Sanskrit word for ‘fish’ and a divinity in the form of a fish is celebrated in the Indian version of the flood myth. An analysis of these narratives is presented in this paper, revealing the possibility of an association with the Indus Valley civilization of the more distant past. These observations indicate that fish symbolism may have occupied a place of prominence in Indus culture from political and religious perspectives. The Matsya territory mentioned in Vedic and epic literature is discussed in light of the chalcolithic cultures of Rajasthan, and it is suggested that this region witnessed successive waves of migration of different cultural groups due to its economic importance related to the exploitation of copper reserves.

Mountain snow depth retrievals from customized processing of ICESat-2 satellite laser altimetry

Snow depth is highly variable across basins, yet most snow depth data in the western U.S. come from sparse in situ point measurements. The water resources community needs accurate snow depth data for improved basin-wide snow depth estimates. The NASA ICESat-2 mission has provided over four years of global satellite laser altimetry measurements since October 2018. Previous studies have shown that standard ICESat-2 data products, when combined with snow-off digital terrain models (DTMs) from airborne laser scanning, have the potential to provide snow depth measurements with varying accuracy depending on factors such as surface slope and canopy cover. In this study we show that ICESat-2 snow depth measurements can be improved with customized data products generated using the SlideRule Earth service. Here we investigate the accuracy of our ICESat-2 SlideRule snow depth method using four years (2019–2022) of reference in situ snow depth measurements and airborne lidar snow depth observations for two watersheds with varying terrain characteristics: the Tuolumne River basin above Hetch Hetchy, CA and the Methow Valley, WA. We observe median differences of −0.14 m (RMSE of 0.18 m) and −0.20 m (RMSE of 0.33 m) between our ICESat-2 snow depth measurements and reference snow depth measurements for the Tuolumne Basin and Methow Valley sites, respectively. While individual ICESat-2 elevation measurements can contain noise, basin-scale aggregation offers robust statistics for snow depth. Differences in accuracy between sites are attributed to terrain characteristics and their spatial distributions. The customized ICESat-2 SlideRule data products used in this study resulted in more accurate median snow depth values, including under canopy, than those found by previous studies using standard ICESat-2 data products in mid-latitude mountainous regions. When combined with snow-off DTMs, the aggregated snow-on ICESat-2 SlideRule observations could provide a new snow depth dataset across the western U.S. and potentially global land surfaces.

Chemical control and herbicide resistance of hairy fleabane (Erigeron bonariensis L.) in Jordan.

The effect of paraquat, oxadiazon and oxyfluorfen herbicides was tested on two populations of hairy fleabane (Erigeron bonariensis L.), collected from a date palm orchard at Tal al-Ramil (Central Jordan Valley) and al-Twal (Northern Jordan Valley) sites using the recommended rates (0.5, 1.25 and 0.792kg a.i ha-1 for each herbicide, respectively) and 10-fold (5, 12.50 and 7.92 kg a.i. ha-1, respectively) under glasshouse conditions. Results showed that the date palm weed population was resistant to the three herbicides at both application rates and al-Twal site population was highly susceptible. Two field experiments were conducted to evaluate the effectiveness of 12 herbicides in controlling the weed in the date palm orchard during the spring of 2017, revealed that E. bonariensis resists paraquat (0.5, 1.0 and 1.5 kg a.i. ha-1), oxadiazon (1.25 kg a.i. ha-1) and oxyfluorfen (0.792 kg a.i. ha-1) herbicides. None of the three herbicides was effective against the weed and treated plants continued to grow normally similar to those of untreated control. Ten-fold higher rates of these herbicides failed to control the weed. The effect of other tested herbicides was variable with bromoxynil plus MCPA (buctril®M), 2,4-D- iso-octyl ester, glyphosate, glyphosate trimesium and triclopyr being the most effective and completely controlling the weed at recommended rates of application. It is concluded that the tested populations of E. bonariensis developed resistance to paraquat, oxadiazon and oxyfluorfen but control of the weed was possible using other herbicides with different mechanisms of action. Herbicide rotation or other nonchemical weed control methods have been suggested to prevent or reduce the buildup and spread of resistant populations of this weed. These results represent the first report of herbicide resistance of E. bonariensis in Jordan.

Mycoheterotrophic plants as indicators of post-agricultural forest regeneration: abundance of Hypopitys monotropa and Monotropa uniflora in post-agricultural forests changes through time

Herbaceous layers in second-growth forests are shaped by past land use. Disturbances such as agriculture may impact populations of mycoheterotrophs, non-photosynthetic mycorrhizal plants that obtain carbon from fungal networks by altering mycorrhizal communities or removing trees they derive carbon from. I tested the hypotheses that two mycoheterotrophic forest herbs increase in abundance during succession and become most common in older forests as plant communities reassemble through time. Distributions of Hypopitys monotropa and Monotropa uniflora were sampled in Athens County, Ohio, USA. I surveyed populations in a 40-site post-agricultural forest chronosequence with five upland and five valley sites in each of four age classes: 40–60, 61–80, 81–100, and >130 years since canopy closure. Aspect and elevation were measured to assess environmental influence. Both H. monotropa and M. uniflora were most common in older stands with EM tree-rich canopy composition and west- or south-facing aspects, indicating influence of historical, biotic, and edaphic factors. Hypopitys was exclusive to forests >80 years old, while M. uniflora was present in younger stands. Abundance of both species was also significantly predicted by Fagaceae basal area. Because EM trees were also most abundant in south- and west-facing uplands, environmental influence appears to be mediated through canopy composition.

Implications for Validation of IMERG Satellite Precipitation in a Complex Mountainous Region

Satellite-based precipitation retrievals such as the Integrated Multi-satellite Retrievals for Global Precipitation Measurement (IMERG), provide alternative data in mountainous regions. In this study, we evaluated IMERG in the Yarlung Tsangbo Grand Canyon (YGC) using ground observations. It was found that IMERG underestimated the total rainfall primarily due to under-detection of rainfall events, with misses being more prevalent than false alarms. We analyzed the relationships between the probability of detection (POD), false alarm ratio (FAR), bias in detection (BID), and Heidke skill score (HSS) and terrain factors. It was found that the POD decreased with elevation, leading to increased underestimation of rainfall events at higher elevations, and the FAR was higher in valley sites. In terms of the hit events, IMERG overestimated the light rainfall events and underestimated the heavy rainfall events and the negative bias in the hit events decreased with elevation. IMERG could capture the early morning peak precipitation in the YGC region but underestimated the amplitude of the diurnal variation. This bias was inherent at the sensor level, and the Global Precipitation Climatology Center (GPCC) calibration partially improved the underestimation. However, this improvement was not sufficient for the YGC region. This study fills the gap in IMERG validation in a complex mountainous region and has implications for users and developers.

Распространение и формирование подземных содовых вод на водосборной площади Верхней Колымы

In the Upper Kolyma basin, mostly hydrocarbonate and sulfate waters are distributed with a predominance of alkaline earth metal cations in the composition. Hydro-carbonates with alkali metal cations (Na+ + K+), distinguished as soda, are found only in local areas in fault zones and those of granite intrusion contacts. They are the least mineralized (no more than 100 mg/dm3) in the seasonally thawed layer and river valley taliks, but even there, in separate foci at the elevation of above 1600 m, soda water springs with the mineralization exceeding 200 mg/dm3 occur. Soda waters in Cretaceous coal-bearing deposits within intermountain artesian basins are the most mineralized (up to 3000 mg/dm3). The association of these waters with deep fault zone has been assumingly traced. The sharp increase of the dissolved carbon dioxide and the carbonic acid anions in waters at local river valley sites is offered as the indicator of the current ingress of carbon dioxide into underground waters. Soda waters with mineralization exceeding 600 mg/dm3 , contained in some samples, are referred to balneal. Hydrogeochemical methods are proposed for further study of the role of deep faults in soda waters formation as well as for the possible use of them for curing and preventing diseases.

Shaking table test for near-valley subway station - Part I: Seismic site effects

As a typical local irregular topography, valley would have a significant influence on the seismic distribution around the local site as well as on seismic responses of near-valley underground structures, which has been evidenced by ground motion observation and field seismic records. However, current knowledge on the seismic site effects of the valley is limited to analytical solutions or numerical methods, and lack of experimental data from physical models. In this paper, a physical model test method based on 1g shaking table for arc-shaped valley topography is proposed, and a series of shaking table tests are carried out to investigate the seismic site effects induced by the valley topography. Details of experimental setup include not only the dynamic similitude design, the laminar model container and the model soil, but also the design and fabrication of arc-shaped valley topography with three kinds of depth-to-width ratios, i.e. 1/3, 1/4, and 1/8, as well as procedure for simulation of seismic excitations considering harmonic waves and actual seismic records. The free-field test case without valley site is also involved and taken as a benchmark comparison to better understand the seismic site effects of valley terrain. Acceleration sensors are placed and embedded in the model soil with different buried depths and distances to the local valley site in order to record the overall free-field seismic responses as well as the local topography effects. Results show that the dynamic response on the surface of model soil exhibits strong spatial variability due to the impact of the local valley topography. Results also indicate the ground acceleration increases within the local site, and the amplification effect is most pronounced at the valley top. The influence of the valley on the acceleration response of the ground is more significant when the predominant frequency of the seismic motions is higher and closer to the natural frequency of the site under different seismic motions. Furthermore, when the depth-to-width ratio of the valley increases, the acceleration amplitude at the valley top gradually increases, and the predominant frequency of Fourier spectrum at the valley top is also amplified. Notably, the Arias intensity amplification factor of the surrounding strata increases significantly due to the local valley topography, and the Arias intensity is also increased with the depth-to-width ratio of the valley.

Shaking table test for near-valley subway station - Part Ⅱ: Seismic response of the station

With the expansion of metro lines in cities especially in megacities, the number of tunnels and subway stations built near urban valley are rapidly growing. However, the influence mechanism of valley on the nearby subway station, which is due to the strong spatial variability of local valley topography during earthquakes, has not been well-understood. In this paper, a series of 1g shaking table tests is performed to investigate the seismic performance of a typical two-story, three-span subway station nearby the valley topography. The stratum is simulated by synthetic model soil (a mixture of sand and sawdust) and the model structure is made by granular concrete with galvanized steel wires. Note that this is done according to the similitude ratio design to ensure the consistency of the structure-soil flexibility ratio between the prototype and the model. The arc-shaped valley topography with three kinds of depth-to-width ratios, i.e. 1/3, 1/4, and 1/8, are designed and fabricated, and a subway station test without valley site was also considered and taken as a comparative benchmark to better understand the seismic response of the subway station affected by the valley topography under harmonic motions and actual seismic records. Result shows that the acceleration response of the top slab of the near-valley structure is significantly larger than that of the case without valley site, and what's more interesting, the subway station exhibits strong lateral racking under the horizontal transverse motion. The active dynamic earth pressure on the sidewall of the near-valley structure is dramatically increasing due to the valley topographic effect. The bending moments of the sidewall close to the local valley is also significantly amplified compared to the benchmark test without valley site, except for the moments of central columns. Results also indicate that, the acceleration amplitude at the top slab gradually increases with the depth-to-width ratio of the valley, and the lateral racking of the near-valley structure is more pronounced when near the valley with a larger depth-to-width ratio under earthquakes.

Examining the Nasca religious network on the south coast of Peru: LA-ICP-MS of Early Nasca ceramics from the Upper Ica Valley (AD 250–450)

This study investigates the geographic extent of a hypothesized pilgrimage network on the south coast of Peru during the Early Intermediate Period (AD 100-650), centered around the important ceremonial site of Cahuachi. It has been argued that Early Nasca style ceramics were manufactured here and distributed to pilgrims from surrounding Southern Nasca Region (SNR) villages as symbols of their pilgrimage, and daily reminders of the Cahuachi ideology. However, the participation of people from other, more distant parts of the Nasca homeland, including the Upper Ica Valley, has not been tested. We do so here by conducting a compositional study using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) on ceramics from two Upper Ica Valley sites, Cerro Soldado and Cerro Tortolita. The results indicate that ceramics recovered from the SNR and the Upper Ica Valley are chemically distinct, supporting different raw material sources and production zones. Furthermore, our results indicate that pottery produced with SNR raw materials is not present at either site. These findings lead us to reassess the direct reach of Cahuachi’s pilgrimage network, and the importance of production centers outside of Cahuachi for contributing to the Nasca iconography and culture.

Seismic performance of small and medium-sized homogeneous earthen dams considering valley site effects in large-scale shaking table tests

Many existing small and medium-sized homogenous earthen dams (SMHEDs), which were constructed worldwide before the establishment of seismic design codes, are prone to fail when subjected to earthquakes. The geologic condition and shape of the valley sites where SMHEDs are located have an important role in the seismic performance of the dams. In this paper, large-scale shaking table tests were conducted to analyse the seismic responses of the SMHED considering valley site effects. A geologic model with a ‘stiff’ dam built in a ‘soft’ valley was employed to simulate the inappropriate site selection and insufficient treatment of the soft soil layers of valley sites during the construction of SMHEDs. The effects of the spectral characteristics of the dam and the frequency components of the input motions on the seismic responses of the SMHED are analyzed in combination with frequency-domain analysis. The results indicate that the local dominant frequencies at different positions of the SMHED exhibit differences due to valley site effects. Under the input motion with different predominant frequencies (FP), the local dominant frequency differences along the dam crest lead to different distribution patterns of the acceleration response along the SMHED crest, and consequently, different damage modes. Under input motions with FP lower than the dominant frequency of the SMHED, the combined damage of collapses and cracks at the end of the SMHED crest tends to develop into massive sliding. Furthermore, recommendations for the aseismic and reinforcement design of SMHEDs are given.

First evidence of a monodominant (Englerodendron, Amherstieae, Detarioideae, Leguminosae) tropical moist forest from the early Miocene (21.73 Ma) of Ethiopia.

Many tropical wet forests are species-rich and have relatively even species frequency distributions. But, dominance by a single canopy species can also occur in tropical wet climates and can remain stable for centuries. These are uncommon globally, with the African wet tropics supporting more such communities than the Neotropics or Southeast Asia. Differences in regional evolutionary histories are implied by biogeography: most of Africa's monodominance-forming species are Amherstieae-tribe legumes; monodominance in Neotropical forests occur among diverse taxonomic groups, often legumes, but rarely Amherstieae, and monodominance in Southeast Asian forests occurs mostly among Dipterocarpaceae species. African monodominant forests have been characterized ecologically and taxonomically, but their deep-time history is unknown despite their significant presence and bottom-up ecological influence on diversity. Herein we describe fossil leaflets of Englerodendron mulugetanum sp. nov., an extinct species of the extant genus Englerodendron (Berlinia Clade, Amherstieae, Detarioideae) from the 21.73 Ma Mush Valley site in Ethiopia. We also document a detailed study of associated legume pollen, which originate from a single taxon sharing characters with more than one extant descendant. Taxonomically, the pollen is most comparable to that from some extant Englerodendron species and supports a likely affiliation with the Englerodendron macrofossils. The Mush Valley site provides the first fossil evidence of a monodominant tropical forest in Africa as represented by leaflets and pollen. Previous studies documented >2400 leaves and leaflets from localities at six stratigraphic levels spanning 50,000-60,000 years of nearly continuous deposition within seven meters of section; all but the basal level contain ≥ 50% E. mulugetanum leaflets. Modern leaf litter studies in African mixed vs. monodominant forests indicates the likelihood of monodominance in the forests that surrounded the Mush paleolake, particularly after the basal level. Thus, we provide an early case for monodominance within the Amherstieae legumes in Africa.