Landscape Stability Research Articles

Depositional and post-depositional processes in human-modified cave contexts of west-central Patagonia (Southernmost South America)

This contribution aims to analyse depositional and post-depositional processes from two volcanic caves (Baño Nuevo 1 and Cueva de la Vieja) from west-central Patagonia, in order to evaluate if natural and anthropogenic processes recorded therein are representative of basin-scale processes. For this purpose, geomorphological, sedimentological, micromorphological, petrographic, magnetic, paleontological and archaeological data are integrated. Results allow correlating the Baño Nuevo 1 and Cueva de la Vieja sequences, comprising a record of ca. 19,000 years. In the first place, the distinction between endogenous and exogenous detritus input, mainly recorded by the mineralogy and lithotypes, provided environmental data related to landscape stability (i.e., vegetation cover). The latter, in turn, could be interpreted as part of a complex feedback associated with major climatic changes. On the other hand, cave weathering rates observed through vertical variations of the gravel fraction, along with bioactivity recorded by percentages of Total Organic Carbon and micromorphological analysis, provided constraints on temperature and/or humidity, being in agreement with available regional information. Main regional palaeoenvironmental changes observed in the sequences were the deglaciation processes, the Pleistocene-Holocene transition, the Holocene amelioration and the Anthropocene. Although no distinctive variations were observed within Holocene deposits, biological processes mainly resultant of the human occupations could have obliterated such finer scale distinctions.

GIS-Based Landscape Stability Analysis: A Comparison of Overlay Method and Fuzzy Model for the Case Study in Slovakia

Landscape stability refers to spatial and functional stability of land use categories over time. This article is focused on the identification and comparison of stable areas in landscape using the overlay method and fuzzy model applying geographic information systems. The study area includes Handlová town and Cigeľ municipality in Slovakia. Both methods were based on land use data from 1955, 1987, 2003, and 2016. After determining stable areas, it was found that the difference between the overlay method and fuzzy model was 29.62 percent. Both methods resulted in an almost identical size of stable built-up area. The stable forest area computed by the fuzzy model was larger than the one calculated by the overlay method. Using the fuzzy model, arable land and grassland categories were mainly found to be unstable. As for the overlay method, the share of stable areas in case of arable land and grassland categories was 5.89 percent of the total stable area. Key Words: fuzzy model, GIS, landscape stability, land use, overlay method, Slovakia.

Palaeocupressinoxylon uniseriale n. gen. n. sp., a gymnospermous wood from the upper Permian of Central Taodonggou, southern Bogda Mountains, northwestern China

A silicified wood, Palaeocupressinoxylon uniseriale n. gen. n. sp., is described from the upper Permian of the Central Taodonggou section, Turpan–Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China. Multidisciplinary data including U–Pb ID–TIMS zircon dating, vertebrate and invertebrate biostratigraphic, and cyclostratigraphic correlation from current and previous studies indicate that the fossil bearing interval is Wuchiapingian (late Permian) in age. The pycnoxylic wood consists of thick-walled tracheids and parenchymatous rays. It is characterized by separated uniseriate radial tracheidal pits, uniseriate ray cells, and cupressoid cross-field pitting. The absence of growth rings in the wood, together with the occurrence of Argillisols, Gleysols, and Histosols above and below the fossil interval, suggests that a stable landscape and a perennially humid climate prevailed in the Taodonggou area during the Wuchiapingian.

High species diversity and turnover in granite inselberg floras highlight the need for a conservation strategy protecting many outcrops.

Determining patterns of plant diversity on granite inselbergs is an important task for conservation biogeography due to mounting threats. However, beyond the tropics there are relatively few quantitative studies of floristic diversity, or consideration of these patterns and their environmental, biogeographic, and historical correlates for conservation. We sought to contribute broader understanding of global patterns of species diversity on granite inselbergs and inform biodiversity conservation in the globally significant Southwest Australian Floristic Region (SWAFR). We surveyed floristics from 16 inselbergs (478 plots) across the climate gradient of the SWAFR stratified into three major habitats on each outcrop. We recorded 1,060 species from 92 families. At the plot level, local soil and topographic variables affecting aridity were correlated with species richness in herbaceous (HO) and woody vegetation (WO) of soil‐filled depressions, but not in woody vegetation on deeper soils at the base of outcrops (WOB). At the outcrop level, bioclimatic variables affecting aridity were correlated with species richness in two habitats (WO and WOB) but, contrary to predictions from island biogeography, were not correlated with inselberg area and isolation in any of the three habitats. Species turnover in each of the three habitats was also influenced by aridity, being correlated with bioclimatic variables and with interplot geographic distance, and for HO and WO habitats with local site variables. At the outcrop level, species replacement was the dominant component of species turnover in each of the three habitats, consistent with expectations for long‐term stable landscapes. Our results therefore highlight high species diversity and turnover associated with granite outcrop flora. Hence, effective conservation strategies will need to focus on protecting multiple inselbergs across the entire climate gradient of the region.

Defining molecular risk in ALK+ NSCLC.

Anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancers (NSCLC) have the best prognosis among metastatic pulmonary malignancies, with a median patient survival currently exceeding 5 years. While this is definitely a major therapeutic success for thoracic oncology, it may not be entirely attributable to rapid drug development and the strenuous clinical efforts. At the genetic level, ALK+ disease is also unique, distinguished by the lowest tumor mutational burden (mean below 3 mutations/Mbp), the lowest frequency of TP53 mutations (20–25%) and very few other co-mutations compared to other NSCLC. The relative simplicity and stability of the genetic landscape not only contribute to the relatively favourable clinical course, but also make study of the effects from individual molecular features easier. EML4-ALK fusion variant 3 (E6;A20) and TP53 mutations were recently identified as main molecular determinants of adverse outcome: they occur in about 30–40% and 20–25% of newly-diagnosed cases, respectively, have possibly synergistic effects and are independently associated with more aggressive disease, shorter progression-free survival under treatment with ALK inhibitors and worse overall survival. Secondary detection of TP53 mutations at disease progression in previously negative patients defines another subset (about 20%) with similarly poor outcome, while detection of ALK resistance mutations guides next-line therapy. As our biological understanding deepens, additional molecular risk factors will be identified and refine our concepts further. The translation of clinical risk at the molecular level and the ability to predict early events are of key importance for individualized patient management and preclinical modeling in order to advance therapeutic options.

Procedencia, manufactura y uso de los materiales líticos en el sitio Laguna Cabeza de Buey 2 (centro de los pastizales pampeanos, Buenos Aires) durante el Holoceno medio y tardío

In this article, we describe the results obtained from the techno-morphological and micro-wear analysis of lithic materials from the excavated sector of Laguna Cabeza de Buey 2 site. Here, we assess data concerning the acquisition, production, and use strategies of these resources, as developed by hunter-gatherer groups under two different palaeoenvironmental conditions. During the Middle Holocene, we identified a semi-arid environment with the presence of a small, brackish and shallow body of water that permitted ephemeral human occupations. The technological characteristics, the low diversity of typological groups, and types of materials processed by the tools —mainly wood and bone— lends support to the presence of temporary human occupations linked to a high mobility pattern. On the other hand, towards the end of the Late Holocene, the palaeoclimatic model indicates humid conditions similar to the present-day, with a more stable landscape —dunes fixed with grassland vegetation— and the presence of a permanent body of water. In this context, there was a much more intense occupation, reflected in the greater quantity and diversity of tools, the wide range of materials processed with them, including skin, wood, bone and non-woody vegetables, as well as the appearance of pottery.

Mid-Cretaceous Paleopedology and Landscape Reconstruction of the Mid-Atlantic U.S. Coastal Plain

AbstractWe identified and described Potomac Formation paleosols from three coreholes in New Jersey and Delaware to interpret depositional history and reconstruct regional landscapes during the climatic transition from the Early to the Late Cretaceous. In total, 103 paleosol profiles were described and grouped into five pedotypes (gray, gray-red, purple, red, and brown) ranging in pedogenic maturity from: 1) weakly developed, immature soils formed under poor drainage conditions (gray and gray-red); to 2) moderately developed soils formed under alternating drainage conditions (purple and red); to 3) well-developed, mature soils formed under well-drained conditions (brown). Geochemical and stable-isotope proxies (Ba/Sr and δ18O on sphaerosiderite) are presented to constrain paleoprecipitation and/or fluvial position and drainage conditions. Potomac Formation Unit I (Barremian to lower Albian) generally displays well-drained, stable landscape conditions upsection, with paleoprecipitation being the main control on development of paleosol type. Potomac Formation Units II (lower Albian to lower Cenomanian) and III (lower Cenomanian) have variable drainage and landscape conditions upsection. Paleoprecipitation exerted a controlling role in the development of paleosol type lower in Unit II, while base-level changes exerted greater influence on landscape conditions upsection into Unit III. Geochemical proxies provide evidence that Unit I was subhumid with episodes of saturation and overall better drainage conditions relative to the overlying units. Units II and III were deposited under more waterlogged conditions, experiencing subhumid to humid conditions, with episodes of enhanced drainage from base-level fall. The use of these proxies is consistent with interpretations made using the macro-features and micro-features of the paleosols and sphaerosiderite δ18O, and emphasizes that the main long-term environmental control on landscape development during this period was initially paleoprecipitation, with progressive influence from base-level changes.

Late Holocene Changes in Erosion Patterns in a Lacustrine Environment: Landscape Stabilization by Volcanic Activity Versus Human Activity

AbstractThe most recent eruption of Mount Fuji (Japan), the VEI 5 Hōei plinian eruption (CE 1707) heavily impacted Lake Yamanaka, a shallow lake located at the foot of Mount Fuji. Here we discuss the influence of the Hōei eruption on the lacustrine sedimentation of Lake Yamanaka using high‐resolution geophysical and geochemical measurements on gravity cores. Hōei scoria fallout had two major impacts on Lake Yamanaka: (i) reduction of the sedimentation rate (from ~0.16 to ~0.09 cm/year) and (ii) the increase of in situ lake productivity. Sedimentation rates after the eruption were relatively low due to the thick scoria layer, trapping underlying sediments in the catchment. The lacustrine system took more than ~170 years to begin to recover from the Hōei eruption: most recently sedimentation recovery has been accelerated by changes in land use. Since the beginning of the twentieth century, vegetated strips delimited cultivated parcels, trapping sediment and minimizing anthropogenic impacts on the sedimentation rate. Over the last decade, the decline of agriculture and the increase of other human activities has led to an increase in the sedimentation rate (~1 cm/year). This study highlights the effect of the grainsize of the volcanic ejecta on the sedimentation rate following a volcanic eruption. Coarse‐grained tephra are difficult to erode. Therefore, their erosion and remobilization is largely limited to intense typhoons when porous scoria deposits are saturated by heavy rains. Moreover, this study suggests that recent anthropogenic modifications of the catchment had a greater impact on the sedimentation rate than the Hōei eruption.

Effect of Newly Created Water Reservoirs on Agricultural Landscape Stability

Effect of Newly Created Water Reservoirs on Agricultural Landscape Stability

The Widdington Sands: High-level Kesgrave Sands and Gravels near the Cam-Stort interfluve, Northwest Essex, UK

A small but stratigraphically significant exposure of Quaternary sandy sediments (Widdington Sands) was observed and recorded in the early 1970s in northwest Essex. These data are here re-examined and re-evaluated, yielding new insights into early proto-Thames aggradation following the marine recession of the Norwich Crag Formation (MIS 74–71, about 2 Ma). As the proto-Thames trajectory shifted south eastwards, a period of landscape stability ensued in the early Middle Pleistocene (MIS 19–13) during which the Valley Farm Soil was formed. This and the succeeding Barham Soil can be recognised in the stratigraphy, the second palaeosol heralding the arrival of glaciation in the Anglian Stage (MIS 12, 480–420 ka). These pedogenic signatures are enclosed within palaeokarstic features in the form of infilled sinkhole pipes. A large doline has functioned as a sediment trap preserving pre-truncation structures including reverse ring faults. These confirm basal support removal leading to upward migration of a dissolution cavity and roof collapse within the sinkhole pipe. The process and timing of subsidence can thus be defined more clearly than for similar features found in comparable Kesgrave aggradations of the Middle Thames. The likely glacitectonic origin of the planar sub-till surface is examined and discussed. Dating of Early Pleistocene fluvial activity is constrained by estimating the height of a former terrace surface whose elevation points to a correlation with the higher Stoke Row Member (MIS 64, 1.8 Ma), suggesting the oldest known proto-Thames activity within southern East Anglia.

Postglacial incision-infill cycles at the Borisoglebsk Upland: Correlations between interfluve headwaters and fluvial network

The article discusses postglacial landscape transformation in the Northern Hemisphere Middle Pleistocene glaciation area located in the center of the Russian Plain. We attempted to verify the regional paleogeographic model by reconstructing the Late Pleistocene incision-infill cycles at the Eastern Borisoglebsk Upland based on a comparison of inactive interfluves headwaters and actual fluvial network palaeoarchives. The study was also aimed to determine the past extent of fluvial systems. Interdisciplinary research of the actual and buried topography, lithology and pedogenic properties of surface deposits was carrid out with remote sensing data interpretation, DGPS survey, and detailed description of geological cores involved. The study was followed by analysis of grain size, chemical and organic contents, microstructure, and numerical dating. Integrating the available results, we propose a scenario of the fluvial network transformation at the Eastern Borisoglebsk Upland over the last 150 ka. At least four fluvial incision stages were determined while network extent has significantly changed through the Late Pleistocene. Three can be generally associated with the regional base level decrease – Late Moscow, Late Valdai and Late Holocene and accompanying isolation of the Nero Lake terraces of 130 m, 100–105 m and 95–98 m. Incision stages were separated by landscape stability or aggradation periods those were asynchronous at the middle and upper parts of the fluvial network. The main agent of initial valley infill appears to be local lacustrine sedimentation altered by alluvial and colluvial deposition towards the second half of Valdai. Revealed landscape conditions variability emphasize the importance of comprehensive local correlations for regional retrospective models.

Monitoring the pollution effects from a gold tailing storage facility on adjacent land through Landscape Function Analysis

Degraded landscapes adjacent to gold tailing storage facilities (TSFs) typically suffer from loss of ecosystem function as a result of seepage pollution. Restoration of these areas has become a primary concern in the fields of environmental science and management within recent decades. To assess the extent of land degradation, detailed monitoring of pollution took place over a period of 4 years on farmland adjacent to a gold TSF in South Africa. The Landscape Function Analysis (LFA) monitoring procedure was developed by David Tongway for the Australian rangelands, and has been utilised in this investigation to assess the impact of seepage pollution on the soil within the aforementioned farmland area. This paper indicated that the LFA procedure could not accurately present landscape stability and ecosystem functionality at the seepage-polluted sites within the short monitoring period presented in this study. It was established that no adverse effects on the natural vegetation were apparent, other than encroachment by Seriphium plumosum, which affected the grazing quality of the area but contributed significantly to the LFA values.

Predicting contemporary range‐wide genomic variation using climatic, phylogeographic and morphological knowledge in an ancient, unglaciated landscape

AbstractAimUnderstanding the spatial distribution of genetic variation across a species’ range is a central tenet in evolutionary biology and the ability to predict such patterns is valuable to conservation management. Genetic diversity and differentiation may be explained by present‐day niche centrality, historical processes, or morphological variation across a species’ range, yet few studies evaluate these factors concurrently. Moreover, there is a particular lack of knowledge of the influence of these factors in ancient, unglaciated landscapes of the Southern Hemisphere. We investigate these concepts for their influence upon spatial patterns of genetic variation in a widespread plant species in a southern biodiversity hotspot.LocationSouth‐western Australia.TaxonCalothamnus quadrifidus.MethodsWe use genotyping‐by‐sequencing to assess genome‐wide diversity and differentiation across the range of Calothamnus quadrifidus, a morphologically variable species that occurs over a wide geographic range in an ancient, unglaciated landscape. We correlated the patterns of genetic diversity and differentiation with those predicted under four hypotheses regarding effects of geographic centrality, climatic centrality, historical phylogeography and morphological subspecies.ResultsWe found spatial variation in genetic diversity and strong population structuring, and while each hypothesis was consistent with some of these patterns, no hypothesis predicted the full extent of genetic diversity or structure in C. quadrifidus.Main conclusionsOur results are indicative of a complex evolutionary history, with multiple factors shaping contemporary genetic variation in C. quadrifidus over time, rather than any one major driving factor. This is enabled by the greater capacity to build complex evolutionary signals in ancient, more stable landscapes like the southwest of Western Australia that are not as predictable as those within the younger, post‐glacial landscapes of the Northern Hemisphere. Finally, our study demonstrates the importance of using an interdisciplinary approach to understanding the spatial patterns of genetic variation across species’ ranges and the influence of ecological, geographical and historical factors.

Ecological and economic basis of anti-erosion stability of forest-agrarian landscapes

The ecological and economic foundations of rational nature management in restoring various kinds of protective forest stands under conditions of severe damage and destruction of wood-shrubby species in the natural-climatic and economic zones of the country were developed. It was determined that using traditional methods of restoration of protective forest plantations in many cases is no longer acceptable due to different levels of damage and substantial changes to economic entities on Earth. However, the main methodological approaches remain. A new methodological approach to restoring forests on the basis of constant adaptation of the existing methodologies for the design and calculation of economic efficiency of new plantings and new ecological-economic conditions and peculiarities has been developed. Certainly ,numerousincorrectly planned forest stands have been created that do not sufficiently fulfill their ecological and economic functions and do not even have a general system of protection of the soil from negative factors. For effective regeneration of plants we have developed a formula for calculating the erosion stability of forest-agrarian landscapes for their optimal recovery through forest shelterbelts. We have developed new features of design and calculation of ecological and economic efficiency of newly created forest ameliorative spaces with new natural-economic conditions for their sustainable regeneration under modern conditions. The transition to environmentally sustainable agriculture of European standards requires fundamentally new solutions to the problem of using forest stands as an organizational component of ameliorative complexes in the context of soil erosion control measures. Soil erosion is one of the main factors of anthropogenic impact on land resources. Intensification of erosion processes leads to substantial degradation of soils, causing great losses to agriculture and generally endangers the safe development of mankind. As long as the process of degradation of the soil continues , the agroecological condition deteriorates and the increased application of mineral and organic fertilizers fails to improve the crop volume , insofar as the crop yield is formed mainly due to the natural soil fertility. In the process of research, we discovered that the expansion of the front intake surface runoff in forestry plantings allows one to increase their effective water-regulative functions. Such an event has a certain practical value, because a large proportion of forest shelterbelts even in satisfactory condition only perform their functionsat 20-30%. Taking into account the indicators of ameliorative-hydrological stress and counter-erosion stability of landscapes in locations of planted forest stands proved to be the most effective method of strengthening the initial contact with runoff ("active") plots .This provides is a unique chance to optimize the ecological economic system of protective forest plantations , especially in newly formed agricultural enterprises under new economic conditions.

Reclaimed artificial coastal territories for the development of urban areas

The article discusses the possibility and perspectives of using the reclaimed artificial areas in the coastal zone of marine estuaries for the sustainable development of urban infrastructure and creation of modern architectural ensembles with the background of green economy using the example of Lakhta-Center on the northern coast of the Neva Bay (St. Petersburg, Russia). The geo-ecological stability of underwater and coastal landscapes of the coastal zone of the Neva Bay is analyzed using side scan sonar. The environmental sensitivity of coastal ecosystems is estimated. The received data can be used on practice for planning the construction work and for the development of the infrastructure of urbanized coastal zone of the Neva Bay. The general geo-ecological situation in the observed area is rather stable. The coastal zone has good perspectives for the development of a sustainable urban infrastructure against the backdrop of the green economy. The special attention should be paid to migration of birds and fish, who are using the North Lakhta coast as a temporary refugium during Spring and Autumn migrations. An effective solution from both environmental and economic points of view could be the organization of the Nature Conservation Reserve, which is spatially associated with the Lakhta Center zone. Such type of the complex using of the coastal zone could be a good example of the spatial planning in the environmentally sensitive area.

A complete Late Weichselian and Holocene record of aeolian coversands, drift sands and soils forced by climate change and human impact, Ossendrecht, the Netherlands

AbstractA stacked aeolian sequence with intercalated soils is presented from the southern Netherlands, which fully covers the Late Weichselian and Holocene periods. An integrated sedimentological (sedimentary structures, grain size), palynological (pollen) and dating approach (radiocarbon, optically stimulated luminescence (OSL)) was applied to unravel climatic and human forcing factors. The dating results of soils and sediments are compatible, and no large hiatuses between the radiocarbon-dated top of the soils and OSL-dated overlying sands were observed. It is argued that the peaty top of wet-type podzols can be used for reliable radiocarbon dating. This study reveals more phases than previously known of landscape stability (Usselo Soil and two podzol soils) and instability (Younger Coversand I and II, two drift-sand units) that are related to Late Weichselian climate change and Holocene human occupation. Regional aeolian deposition in source-bordering (river) dunes (Younger Coversand II) took place in the second part of the Younger Dryas, after 12.3 ka cal. BP, implying a delayed response to Younger Dryas cooling, vegetation cover decline and river pattern change of the Scheldt. The onset of podzolisation and development of ericaceous vegetation occurred prior to the introduction of Neolithic farming, which is earlier than previously assumed. Early podzolisation was followed by a short phase of local drift-sand deposition, atc.5500 cal. BP, that possibly relates to agriculture. Strong human impact on the landscape by deforestation and agriculture resulted in a second phase of widespread drift-sand deposition covering the younger podzol soil after AD 1000.

Identification of vulnerable regions to soil loss under the dynamic saturation process

This study presents a theoretical framework based on power law distribution to identify the vulnerable regions to soil loss in Susu river basin at Cameron Highlands, Malaysia by using the geomorphologic factors from Digital Elevation Model (DEM). Drainage area is used to describe the runoff aggregation structure of the watershed which represents the magnitude of discharge. Stream power is also used to describe the energy expenditure pattern of the watershed. They are fitted to power law distribution by means of the maximum likelihood to estimate the threshold for soil loss. The landscape stability condition is assessed through the mechanism of channel initiation. Two regions in the slope area plot are recognized as the regimes susceptible to soil loss, in that discharge, local slope and energy are sufficient for the initiation of soil movement. The result is further improved by incorporating the Topographic Wetness Index (TWI) aiming to locate vulnerable regions to soil loss under the dynamic saturation process. The final result indicates that the vulnerable regions expand from perennial reaches to ephemeral reaches as saturation process develops. It implies the transition of runoff generation from groundwater in perennial reaches to surface runoff in ephemeral reaches. Identification of soil loss vulnerable regions under the dynamic saturation process helps in planning of the mitigation measures for soil erosion.

Integrating ichnology and paleopedology in the analysis of Albian alluvial plains of the Parnaíba Basin, Brazil

Studies integrating ichnology and paleopedology in paleoenvironmental interpretations are uncommon in Brazilian continental sedimentary successions. Nevertheless, they are crucial for understanding the interactions between sediments, organisms and soil-forming processes. The Albian sediments of the Parnaíba Basin were deposited in continental environments. These are constituted of very fine-to fine-grained sandstones, interbedded with mudstones and composite and compound paleosol profiles with preserved invertebrate and vertebrate trace fossils and rhizoliths. In this study, ichnological, sedimentological and paleopedological data are integrated in order to define the paleoenvironmental conditions of the Albian deposits of the Parnaíba Basin. The depositional environment is interpreted as alluvial with floodplain and crevasse splay deposition. In the paleosol profiles five invertebrate ichnogenera, one vertebrate ichnogenus and two types of rhizoliths were recognized and attributed to Scoyenia ichnofacies. The water saturation level of paleosols evidenced by the distribution of redoximorphic features and the variation of ichnofossil types suggests that the profiles were developed under moderately well drained conditions with short periods of water retention and that the paleoclimate was seasonal and characterized by alternating wet and dry seasons. The alluvial paleoenvironment was characterized by periods of landscape stability in which the pedogenesis exceeded the sedimentation rates and resulted in formation of soil profiles.

Effects of Cyanobacterial Soil Crusts on Surface Roughness and Splash Erosion

AbstractSoil surface roughness (SSR) modifies interactions and feedback processes between terrestrial and atmospheric systems driven by both the abiotic and biotic components of soils. This paper compares SSR response to a low‐intensity multiday rainfall event for soils with and without early successional stage cyanobacteria‐dominated biological soil crusts (CBCs). A rainfall simulator was used to apply 2, 5, and 2 mm of rain separated by a 24‐hr period over 3 days at an intensity of 60 mm/hr. Changes in SSR were quantified using geostatistically derived indicators calculated from semivariogram analysis of high‐resolution laser scans. The CBCs were stronger and splash erosion substantially less than from the physical soil crusts. Prior to rainfall treatment, soils with CBCs had greater SSR than those without. The rainfall treatments caused the physical crusted soils to increase SSR and spatial patterning due to the translocation of particles, soil loss, and the development of raindrop impact craters. Rainfall caused swelling of cyanobacterial filaments but only a slight increase in SSR, and raindrop impact cratering and splash loss were low on the soils with CBCs. There is no relationship between random roughness and splash erosion, but an increase in splash loss was associated with an increase in topographic roughness and small‐scale spatial patterning. A comparison of this study with other research indicates that for rainfall events up to 100 mm, the effectiveness of CBCs in reducing soil loss is >80% regardless of the rainfall amount and intensity, which highlights their importance for landscape stabilization.

Human occupation strategies and related environmental-climate during the middle and late Holocene in central Pampas of Argentina

The main objective of this work is to generate and integrate interpretations of human occupation strategies and inferences of the environmental-climatic conditions in the central Pampas during the middle and late Holocene. We present a novel archeological–geological–paleoecological analysis in the area of the Cabeza de Buey lake, placed in an aeolian landscape. During the middle Holocene, two events of human occupations were recognized at Laguna Cabeza de Buey 2 archeological site. Both events present a small amount of lithic materials, a low diversity of tools and activities developed with them (principally hard material), and the hunting and primary processing of artiodactyls. These evidences suggest a locus of specific activity associated with an ephemeral human settlement under climate conditions drier than present and the presence of small, brackish, and shallow water bodies. For the late late Holocene, the hunter-gatherer occupation has a higher depositional rate of lithic assemblage, stones with diverse origins, presence of pottery fragments, a great lithic tool diversity, knapping techniques, and activities developed with these tools (processing wood, bone, hide, non-woody plant, and soft material). These evidences reveal an occupation with a higher degree of recurrence represented by a locus of multiple activities associated with a more stable landscape, such as an environment of dunes fixed by grass vegetation, and the establishment of a permanent water body. The different environmental characteristics for the middle and late Holocene in this area promoted that human groups develop two different patterns of mobility, settlement and use of space.