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Journal articles on the topic 'Hilltops'
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1
Nandikar, Mayur D., Priyanka T. Giranje, and Durga C. Jadhav. "Floristic enumeration of Torna Fort (Western Ghats, India): a storehouse of endemic plants." Journal of Threatened Taxa 10, no. 7 (June 26, 2018): 11895. http://dx.doi.org/10.11609/jott.3705.10.7.11895-11915.
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The forts on hilltops of the Sahyadri (northern Western Ghats) have seen a turbulent historical past and are famous for their architectural style and cultural heritage. Besides this, these hilltops are home to an incredible plant diversity. One of the highest hilltop forts (ca. 1,403m) the Torna, has been explored since 2012 for floral assessment. The study documented ca. 399 plant species of which about 28% are endemic to the Western Ghats and 16 monotypic species were recorded. A brief account of the immense floristic diversity and new findings from Torna fort are summarized in the present article.
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Menšík, Petr, and Milan Menšík. "An Overview of Southern Bohemian Hilltop Settlements from Prehistory to the Late Middle Ages." Archaeologia Lituana 19 (December 20, 2018): 34–61. http://dx.doi.org/10.15388/archlit.2018.19.3.
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[full article, abstract in English; abstract in Lithuanian]
The Southern Bohemian Region belongs to regions where many hilltop settlements had been built since the Early Stone Age. However, the first fortified systems were built in the Late Bronze Age, as hilltops, mountain peaks, and promontories were fortified using complex systems of ramparts and ditches. This phenomenon thereafter continued into younger prehistoric periods, especially the Early Iron Age, resulting in the foundation of hilltops in the Early Middle Ages, starting with the 9th century and frequently continuing in the form of castles and manor houses built in the Middle Ages and the Modern Period. This paper is not only an attempt to summarize and survey the use of hilltop sites and the continuity of settlements but also an effort to state their classification, characteristics, and function considering their practical, social and symbolical roles, which can be detected in both prehistoric (sophisticated fortifications with no practical use, relocation) and medieval (show of power, the question of defence) heritage.
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Montaño, Noé Manuel, Ana Lidia Sandoval-Pérez, Felipe García-Oliva, John Larsen, and Mayra E. Gavito. "Microbial activity in contrasting conditions of soil C and N availability in a tropical dry forest." Journal of Tropical Ecology 25, no. 4 (July 2009): 401–13. http://dx.doi.org/10.1017/s0266467409006166.
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Abstract:We studied the relationships between soil nutrient availability and microbial biomass and activity of two contrasting soil conditions in a tropical deciduous forest in western Mexico. Hilltops have higher pH, water, dissolved organic C, and ammonium concentrations than hillslopes. Our main hypothesis was that soil microbial biomass, microbial activity and bacterium species richness would be higher in soils with high availability of nutrients. Fifteen soil cores, 0–5 cm depth, were taken in the dry, early rainy and rainy season, from each of the ten replicate plots in hilltop and hillslope positions located on three contiguous small watersheds. We measured moisture, C, N and P availability, potential C mineralization, net nitrification, microbial biomass and culturable heterotrophic and nitrifying bacteria in composite samples from each plot. Microbial biomass, species richness of culturable heterotrophic bacteria and C mineralization were significantly higher on hilltops than on hillslopes. Net nitrification was, in contrast, significantly higher on hillslopes than on hilltops and counts of culturable nitrifying bacteria were also significantly higher in the rainy-season samples. Hilltops and hillslopes had low similarity in composition of culturable heterotrophic bacterial species, particularly during the rainy season. The results suggested that C and N availability and seasonal changes in soil moisture are important controlling factors for some soil culturable-bacterial species, which may affect both C mineralization and nitrification in these tropical deciduous forest soils.
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Swanson, Steve. "Documenting Prehistoric Communication Networks: A Case Study in the Paquimé Polity." American Antiquity 68, no. 4 (October 2003): 753–67. http://dx.doi.org/10.2307/3557071.
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Hilltop features reported around the site of Paquimé, the political center of a prehistoric complex polity in northwest Chihuahua, Mexico, have been interpreted as a fire-signaling network by archaeologists. If these hilltop platform features functioned as such a communication system, it provides important information for our interpretation of regional integration and interaction for the Paquimé polity. This paper reports the results of a survey of hilltops in the area and a subsequent GIS-based intervisibility analysis, which determined that a series of hilltop platforms in the region were ideally situated for fire-signaling purposes. I discuss the need for implementing tests for intervisibility and tests for determining the significance of that intervisibility, and then consider some implications of the Paquimé fire-signaling system on sociopolitical organization and integration.
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Fan, Yan Rong, Shuang Lin Chen, Hua Lin, Qing Ping Yang, Yi Cong Hong, and Zi Wu Guo. "Effects of Anthropogenic Disturbance Measures on Plant Diversity of Understory Vegetation in Moso Bamboo Forests." Advanced Materials Research 726-731 (August 2013): 4288–93. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.4288.
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Anthropogenic disturbance measures have complex effects on understory plants. In order to establish a theoretical basis for moso bamboo forest sustainable management, three types of moso bamboo forests with many years not weeding, hilltops weeding and herbicides weeding were choosed. And species names, numbers and coverages of all arbors, shrubs, herbs and vines were recorded in every quadrat. Species composition and α-diversity were analyzed to compare understory vegetation under the three types of moso bamboo forests with consistent stand structure and site conditions. There are four major findings in this study: (1) 74 species belonged to 47 families and 58 generas which are recorded in the three types of moso bamboo forests. Many years not weeding, hilltops weeding and herbicides weeding are respectively 33 families 39 genera 40 species, 33 families 37 genera 41 species and 37 families 43 genera 49 species. (2) Dominant species of arbors and shrubs within hilltops weeding and herbicides weeding moso bamboo forests are less than the ones of many years not weeding moso bamboo forest, whereas dominant species of herbs increased. Meanwhile, co-dominant specie of arbors is Cunninghamia lanceolata, shrubs is Rubus reflexus, and herbs are Melastoma dodecandrum and Dicranopteris dichotoma. (3) Richness of herbicides weeding and hilltops weeding moso bamboo forests is significantly lower than (p<0.05) the one of many years not weeding moso bamboo forest, and Containing absolute abundance diversity index (I) of hilltops weeding moso bamboo forest is also significantly lower than (p<0.01) many years not weeding moso bamboo forest. The differences of Simpson dominance index (C), Simpson diversity index (D),Shannon-Wiener diversity index (H) and Pielou evenness index (J) among the three types of moso bamboo forests are not significant. Considering understory plant diversity and system structure stability analysis, anthropogenic hilltops weeding measure is suggested to be used for understory vegetation interference.
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Oliveira, Guilherme de Castro, and Elpidio Inacio Fernandes Filho. "AUTOMATED MAPPING OF PERMANENT PRESERVATION AREAS ON HILLTOPS." CERNE 22, no. 1 (March 2016): 111–20. http://dx.doi.org/10.1590/01047760201622012100.
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ABSTRACT Permanent Preservation Areas (PPAs) on hilltops are among the many areas protected by the New Forest Code in Brazil. Mapping of these involves difficult interpretation and application of the Law, as well a complex task of translating it in map algebra. This paper aims to present, in detail, a methodological model for delimitation of PPAs on hilltops, according to the Brazilian new Forest Code (NFC, Law 12,651/2012). The model was developed in Model Builder for ArcGIS 10.2, and is able to map the PPAs in any digital terrain model. However, field validations are required to verify its efficiency. There is need for legal standardization of criteria that may cause subjectivity in delimitation. The organization of these data on a large scale is very important, as example, to the Rural Environmental Registry, which provides georeferencing of all rural properties and its protected areas in Brazil.
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Baden, H. M., T. Särkinen, D. A. Conde, A. C. Matthews, H. Vandrot, S. Chicas, C. Pennil, et al. "A BOTANICAL INVENTORY OF FOREST ON KARSTIC LIMESTONE AND METAMORPHIC SUBSTRATE IN THE CHIQUIBUL FOREST, BELIZE, WITH FOCUS ON WOODY TAXA." Edinburgh Journal of Botany 73, no. 1 (November 10, 2015): 39–81. http://dx.doi.org/10.1017/s0960428615000256.
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The Chiquibul Forest Reserve and National Park in Belize is a priority conservation area within the ‘Maya Forest’ in Central America. Although taxonomic data are essential for the development of conservation plans in the region, there is limited knowledge of the existing species in the area. Here we present a botanical species list of mostly woody taxa based on voucher specimens, with particular focus on the Raspaculo watershed in the eastern part of the National Park. Within the Raspaculo watershed, a comparison is made between 0.1 ha of valley floor and 0.1 ha of hilltop vegetation, sampling trees, shrubs, palms and lianas ≥2.5 cm diameter at breast height. Additionally, a 1 ha plot was established in the Upper Raspaculo watershed. Our study shows 38 new species records for the region, and important additions to the flora of Belize. New records were recorded from forests on both metamorphic and karstic substrate, including previously overlooked hilltop forest elements. Quantitative assessment of vegetation across elevation zones shows distinct elements dominating on valley floors and hilltops. Our results show that the Chiquibul contains at least 58% of Belize’s threatened plant species, and represent a source of information for the management and conservation of the area.
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Emelin, Maxim, and Radu Tatar. "Axion hilltops, Kahler modulus quintessence and the swampland criteria." International Journal of Modern Physics A 34, no. 28 (October 10, 2019): 1950164. http://dx.doi.org/10.1142/s0217751x19501641.
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We study the interplay among extrema of axion potentials, Kahler moduli stabilization and the swampland criteria. We argue that moving away from the minima of nonperturbatively generated axion potentials can lead to a runaway behavior of moduli that govern the couplings in the effective field theory. The proper inclusion of these degrees of freedom resolves the conflict between periodic axion potentials and the gradient de Sitter criterion, without the need to invoke the refined de Sitter criterion. We investigate the possibility of including this runaway direction as a model of quintessence that satisfies the swampland criteria. Using a single nonperturbative effect, the maximum along the axion direction provides such a runaway direction, which is unstable in the axion directions, sensitive to initial conditions and too steep to allow for a Hubble time of expansion without violating the field excursion criterion. Adding a second nonperturbative effect generates a saddle point in the potential satisfying the refined de Sitter criterion, which solves the steepness problem and improves the initial conditions problem although some fine-tuning remains required.
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Nilssen, Arne C., and John R. Anderson. "The mating sites of the reindeer nose bot fly: not a practical target for control." Rangifer 15, no. 2 (January 1, 1995): 55. http://dx.doi.org/10.7557/2.15.2.1167.
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The reindeer nose bot fly Cephenemyia trompe aggregates on hilltops/mountaintops to mate. Although active only for brief periods on certain days, males have been collected only from such sites. To evaluate possible suppression of the fly population by killing males (by insecticides or traps) at such sites, the density of sites and the number of males at each site were monitored in a summer grazing area of the semidomestic reindeer host (Rangifer tarandus) in Finnmark, northern Norway. In an area of ca. 20 km2, 19 mating sites were detected and examined during 4 hours on one day. The number of males observed at most sites was 5-16 (range 3-60). Minor hilltops had few males but at some sites >20-60 flies were dispersed over an area of at least 100 m2. It is concluded that mating sites in the study area are too numerous, and also used by many beneficial non-target species, to be practical targets for control of the species.
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McCrink, Timothy P., Chris J. Wills, Charles R. Real, and Michael W. Manson. "Effects of Topographic Position and Geology on Shaking Damage to Residential Wood-Framed Structures during the 2003 San Simeon Earthquake, Western San Luis Obispo County, California." Earthquake Spectra 26, no. 3 (August 2010): 779–802. http://dx.doi.org/10.1193/1.3459160.
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A statistical evaluation of shaking damage to wood-framed houses caused by the 2003 M6.5 San Simeon earthquake indicates that both the rate and severity of damage, independent of structure type, are significantly greater on hilltops compared to hill slopes when underlain by Cretaceous or Tertiary sedimentary rocks. This increase in damage is interpreted to be the result of topographic amplification. An increase in the damage rate is found for all structures built on Plio-Pleistocene rocks independent of topographic position, and this is interpreted to be the result of amplified shaking caused by geologic site response. Damage rate and severity to houses built on Tertiary rocks suggest that amplification due to both topographic position and geologic site response may be occurring in these rocks, but effects from other topographic parameters cannot be ruled out. For all geologic and topographic conditions, houses with raised foundations are more frequently damaged than those with slab foundations. However, the severity of damage to houses on raised foundations is only significantly greater for those on hill slopes underlain by Tertiary rocks. Structures with some damage-resistant characteristics experienced greater damage severity on hilltops, suggesting a spectral response to topographic amplification.
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Fordyce, IR, GA Duff, and D. Eamus. "The Ecophysiology of Allosyncarpia ternata (Myrtaceae) in Northern Australia: Tree Physiognomy, Leaf Characteristics and Assimilation at Contrasting Sites." Australian Journal of Botany 43, no. 4 (1995): 367. http://dx.doi.org/10.1071/bt9950367.
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Allosyncarpia ternata S.T.Blake, a large, evergreen tree endemic to the northern part of the Northern Territory, Australia, dominates the canopy in a wide variety of habitats, including monsoon rainforest on ravine floors, open forest and woodland on cliffs, screes and sandsheets, and open woodland on ridges and hilltops. This study examines tree physiognomy, leaf characteristics and leaf assimilation rates of A. ternata growing at sites with strongly contrasting micro-climates near Baroalba Springs, Kakadu National Park. By comparison with trees growing on the ravine floor, cliff and hilltop trees are generally shorter, they branch lower, are more frequently multi stemmed and have higher ratios of canopy width to height, while their leaves are generally smaller and thicker and contain less chlorophyll a and chlorophyll b per unit dry weight. They have lower mean specific leaf areas and higher mean stomatal densities. Assimilation measurements on leaves at a cliff site showed significantly higher rates of light-saturated assimilation during the morning than in the afternoon. On the ravine floor, by contrast, assimilation responses to changes in light flux density did not vary significantly through the day. Leaves of trees growing on the ravine floor had lower values oi light-saturated assimilation and light compensation point, and higher values of apparent quantum yield than cliffside leaves.
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Fordyce, I. R., G. A. Duff, and D. Eamus. "The Water Relations of Allosyncarpia ternata (Myrtaceae) at Contrasting Sites in the Monsoonal Tropics of Northern Australia." Australian Journal of Botany 45, no. 2 (1997): 259. http://dx.doi.org/10.1071/bt96016.
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Allosyncarpia ternata S.T.Blake (Myrtaceae) is an evergreen tree, restricted largely to rocky habitats on the Arnhem Land Plateau in the wet–dry tropics of northern Australia. Allosyncarpia ternata grows in a wide range of habitats, including sites near permanent springs, where it forms a distinctive closed-canopy forest with an understorey of rainforest plants, and sites on exposed cliffs and hilltops, where it occurs in open forest and woodland. Leaf water relations differ markedly between these contrasting sites. During the dry season, trees at open sites show strong diurnal hysteresis in stomatal conductance (gs); afternoon depressions in gs coincide with regular afternoon increases in vapour pressure deficit. Pressure–volume analyses indicate that A. ternata maintains turgor down to leaf water potential values of about –2.8 MPa, close to the minimum experienced by hilltop leaves late in the dry season. By contrast, trees on the ravine floor, with year-round access to water, exhibit much smaller diurnal and seasonal variation in stomatal conductance and little seasonal variation in leaf water potential. It is concluded that this flexible response in leaf water relations to seasonally dry conditions is partly responsible for the ability of A. ternata to occupy and dominate the vegetation in such a wide variety of habitats. The near confinement of the species to the Arnhem Land Plateau is in part due to the water-holding capacity of the bedrock.
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Lucas da Costa-Lima, James, and Earl Celestino de Oliveira Chagas. "Two New Species of Erythroxylum (Erythroxylaceae) from the EspinhaçoRange, Eastern Brazil." Systematic Botany 45, no. 1 (March 25, 2020): 96–101. http://dx.doi.org/10.1600/036364420x15801369352351.
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Abstract—Two new species of Erythroxylum endemic to the Espinhaço Range, in eastern Brazil, are described. Erythroxylum itan occurs in seasonal forest on hilltops in the Itacambiruçu River valley, in the Grão Mogol region of northern Minas Gerais, and E. kanga occurs in campo rupestre and cerrado vegetation along the Espinhaço Range, in the states of Bahia and Minas Gerais. The new species are compared with morphologically similar species and illustrations and comments about distribution and habitat are provided. In addition, we present an updated list of Erythroxylum species from the Espinhaço Range.
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Ben-Asher, Matan, Itai Haviv, Onn Crouvi, Joshua J. Roering, and Ari Matmon. "The convexity of carbonate hilltops: 36Cl constraints on denudation and chemical weathering rates and implications for hillslope curvature." GSA Bulletin 133, no. 9-10 (January 15, 2021): 1930–46. http://dx.doi.org/10.1130/b35658.1.
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Abstract Carbonate hillslopes are often soil mantled and display a classic convex morphology. In this study we examine controls on carbonate hillslope denudation and morphology using a modified regolith mass balance equation to account for chemical weathering and dust input—two fluxes that are commonly neglected in settings with silicate-dominated bedrock. We utilize seven study sites in the Eastern Mediterranean across a significant gradient in the mean annual rainfall and dust deposition flux. Combining cosmogenic 36Cl-derived hilltop denudation rates with an estimate of the regolith chemical depletion and the quantified fraction of dust in the regolith we predict hilltop curvature and compare our predictions with observations based on high-resolution airborne LiDAR (light detection and ranging). Denudation rates vary from 5 to 210 mm/k.y. and increase with mean annual rainfall. Less resistant carbonates (chalk) experience faster denudation rates relative to more resistant dolo-limestone and are less prone to chemical weathering. Soil production exhibits a humped dependency on soil thickness. The observed hilltop curvature varies as a function of rainfall and dust flux with a minimum at sub-humid sites. While trends in hilltop convexity are often solely attributed to variations in erosion rate, our results illustrate the additional effects of dust production and chemical depletion. Our mass balance model implies that drier sites in the south probably experienced a more intricate history of regolith production due to dust flux fluctuations. Thus, by incorporating dust flux and chemical weathering to the classic hillslope evolution model we are able to identify a complex relation between hilltop curvature, soil production, and climate.
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Ribon, Rômulo, Luane Reis dos Santos, Paulo De Marco, and Miguel Ângelo Marini. "Topography as a determinant of bird distribution in secondary Atlantic Forest fragments." Journal of Tropical Ecology 37, no. 5 (August 13, 2021): 228–34. http://dx.doi.org/10.1017/s0266467421000328.
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AbstractThe spatial distribution of Neotropical birds at local scales is often associated with plant successional stages and unique microhabitats such as bamboo stands and treefall gaps. Only 15% of the Atlantic Forest remains, yet this habitat is home to more than 200 endemic birds. Understanding the distribution of bird species within the Atlantic Forest can improve the test of ecological hypotheses related to habitat use and habitat selection. This study analyses the distribution of birds among different types of relief (lowlands, ravines, hillsides, and hilltops) in 41 forest fragments of different sizes (1 to 384.5 ha) within the Atlantic Forest, south east Brazil. The presence and absence data were analysed with dynamic occupancy models to determine the influence of area and topography in the distribution of bird species. Of the 169 species detected, we were able to estimate an occupancy probability of 67. Among them, relief type was an important variable for 26 species (39%). Most species showed a preference for lowlands and ravines, and some showed an association of combinations of these two reliefs with hillsides and hilltops. These preferences might be related to distribution of preferred food, nesting microhabitats, and thermoregulation. For the endemic and threatened Atlantic Forest mountain birds, the ecological association with areas of relief is a strong, and previously unsuspected, spatial distribution pattern. Our results suggest that the ecology and distribution of birds in tropical forests across hilly regions could be better understood if topography is considered. This pattern should be better investigated among other taxa in tropical forests.
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Tuck, Anthony, Kate Kreindler, and Theresa Huntsman. "Excavations at Poggio Civitate (Murlo) During the 2012--2013 Seasons: Domestic Architecture and Selected Finds From the Civitate A Property Zone." etst 16, no. 2 (November 1, 2013): 287–306. http://dx.doi.org/10.1515/etst-2013-0016.
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Abstract Excavations over the course of the 2012 and 2013 seasons at Poggio Civitate (Murlo) have revealed the presence of domestic architecture in an area immediately to the southwest of the Piano del Tesoro plateau, the portion of Poggio Civitate that preserves evidence of monumental building from the Orientalizing and Archaic phases of the site’s occupation. At least two building phases have been discovered in the eastern extent of the hill’s Civitate A property zone and they reveal that a small rectilinear structure dating to the late seventh century BCE was superimposed on an earlier, curvilinear structure. These architectural discoveries indicate that the opulent Orientalizing structures on the Piano del Tesoro plateau were not only visible to people on nearby hilltops, but also to a community that stood to its immediate west. While additional excavation is needed to clarify a number of questions about Civitate A, it is striking that its inhabitants appear to have had access to at least a few items of notable quality and potential social value, many of which were also used by the social elite living on the plateau. In addition, the number of planed, cut and carved antler, horn and bone objects and fragments recovered within the interior area of Structure 1 raises the possibility that artisans employed in the service of Poggio Civitate’s ruling elite created similar artifacts for their own domestic arena. Future excavations both in Civitate A as well as on other hilltop settlements in the region of Murlo should provide even greater insight into these and many other questions concerning this remarkably well-preserved site and the activities of its ancient inhabitants.
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Hopper, Stephen D., and Nathan K. McQuoid. "Two new rare species and a new hybrid in Eucalyptus series Tetrapterae (Myrtaceae) from southern coastal Western Australia." Australian Systematic Botany 22, no. 3 (2009): 180. http://dx.doi.org/10.1071/sb06034.
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Three new rare taxa allied to the conspicuous, common four-winged mallee (Eucalyptus tetraptera Turcz.) are described. E. sweedmaniana is a large-leaved and prostrate coastal mallee known only from Mount Arid, Western Australia. E. brandiana, a non-lignotuberous mallet, occupies spongolite hilltops and escarpments near the Fitzgerald River Inlet in Fitzgerald River National Park, Western Australia. A single hybrid mallet, E. arborella × brandiana, is described from the type locality of E. brandiana. Both new species and the new hybrid show potential for horticultural use, given their compact habit, large leaves and conspicuous red floral hypanthia and fruits. E. arborella × brandiana and E. brandiana are particularly at risk, being highly localised endemics that are killed by fire.
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Meyer, William B. "The Poor on the Hilltops? The Vertical Fringe of a Late Nineteenth-Century American City." Annals of the Association of American Geographers 95, no. 4 (December 2005): 773–88. http://dx.doi.org/10.1111/j.1467-8306.2005.00486.x.
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Bernard, Seth G. "CONTINUING THE DEBATE ON ROME'S EARLIEST CIRCUIT WALLS." Papers of the British School at Rome 80 (September 24, 2012): 1–44. http://dx.doi.org/10.1017/s0068246212000037.
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Rome's pre-Imperial circuit walls pose a particular problem of reconstruction: collectively, their 11 km course represents the largest single monument of the early city, but our understanding of this structure is based on an assemblage of several dozen disparate archaeological sites. After tracing the interpretation of these fragments from antiquity to the present, this article examines the literary, topographical and archaeological evidence for the wall's character and date. Ultimately, the non-archaeological data are inconclusive, and the material evidence seems to affirm an early phase (sixth centurybc) focused on individual hilltops, rather than encompassing all hills within a full course. Following this logic, I continue to question the presence of a unified circuit wall at Rome prior to the mid-Republic (fourth centurybc). A concluding section reviews the historical circumstances in support of this view.
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Meslem, Abdelghani, Fumio Yamazaki, Yoshihisa Maruyama, Djillali Benouar, Abderrahmane Kibboua, and Youcef Mehani. "The Effects of Building Characteristics and Site Conditions on the Damage Distribution in Boumerdès after the 2003 Algeria Earthquake." Earthquake Spectra 28, no. 1 (February 2012): 185–216. http://dx.doi.org/10.1193/1.3675581.
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This study highlights the major contributing factors to the observed damage distribution in the city of Boumerdès after the 2003 Algeria earthquake. The results of field investigations and statistical analyses show that a majority of the damaged buildings, mostly mid-rise reinforced concrete (RC) moment-frame systems, were located on steep slopes and small hilltops, along river valleys. The horizontal-to-vertical (H/V) ratios from free-field microtremor measurements at these sites did not show clear results. In contrast, buildings with the same structural characteristics located on flat ground did not suffer much damage, and clear peaks were observed from the H/V ratio curves. The amplification effects of topography have not been incorporated into the revised Algerian seismic code, but the results from this study show the importance of considering this factor when designing new buildings for earthquake resistance.
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Dawson, P., and G. Weste. "Changes in the Distribution of Phytophthora cinnamomi in the Brisbane Ranges National Park Between 1970 and 1980-81." Australian Journal of Botany 33, no. 3 (1985): 309. http://dx.doi.org/10.1071/bt9850309.
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The distribution of Phytophthora cinnamomi in the Brisbane Ranges National Park of Victoria was mapped and related to vegetation susceptibility, disease severity and past distribution. P. cinnamomi extended its distribution from 1% of the park in 1970 to 31% in 1980-81. The dispersal of the pathogen has occurred through roadworks and subsequent drainage of water-borne zoospores. In 1980-81, 50% of 1191 grids (250 x 250 m) occurred in susceptible vegetation (sclerophyllous forest/woodland). Of these, 45% (266 grids) were moderately diseased and 16% (95) severely diseased. Stands of dead trees occurred in 29 severely diseased grids which were in shallow gullies with impeded drainage. The 39% (231) of susceptible vegetation which remained unaffected occurred mainly on ridges and hilltops. P. cinnamomi was isolated from 3% of apparently resistant vegetation (graminoid forest/woodland). Restriction of access is recommended to the remaining areas of susceptible unaffected vegetation.
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Langlie, BrieAnna S. "Late Intermediate Period Plant Use at a Colla Hillfort, Puno, Peru (AD 1300–1450)." Latin American Antiquity 31, no. 4 (June 18, 2020): 702–19. http://dx.doi.org/10.1017/laq.2020.28.
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In the Lake Titicaca Basin during the Late Intermediate period (LIP; AD 1100–1450), people's lives were overwhelmingly structured by warfare. Previous research in the region has shed light on how martial conflict between and possibly among competing ethnic groups motivated people to live in fortified villages on defensive hilltops. At the same time, there was a centuries-long drought that threatened agricultural production. Little is known about the plant use of people living in hillforts during this arduous time. Drawing on macrobotanical information collected from Ayawiri, one of the largest hillforts in the northern Titicaca Basin, I argue that the food stuffs and plants used were locally grown. Additionally, these findings indicate a possible departure from earlier symbolically charged and ritually important plant consumption practices based on the lack of imported maize. This research sheds light on how people adapted their domestic and agricultural strategies to warfare and climate change during the LIP.
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Ruth, A., B. B. Johnson, and T. J. Fowler. "Geomorphic controls on aluminium in acid soils of the Axe Creek catchment, Victoria." Soil Research 36, no. 6 (1998): 951. http://dx.doi.org/10.1071/s97072.
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This study investigates the influence of terrain, including steepness and position in slope, on soil pH, extractable aluminium (Al), and organic carbon (OC) in the Axe Creek catchment, Victoria. Both soil pH and Al were determined by use of 1 : 5 soil : 0·01 M CaCl2 extracts, with Al measured colorimetrically using a modified pyrocatechol violet method. Although all soils were acidic, the Al concentration was highest on the hilltops (>10 mg/kg) and lowest at base-of-slope sites (<1 mg/kg). The concentration of Al was generally inversely related to soil pH. However, on average, a lower Al concentration was found in the top 10 cm than in the interval from 10 to 30 cm, even though the soil pH remained relatively constant throughout the top 30 cm. The lower Al concentration in the surface layer corresponded to a substantially higher level of OC near the surface, suggesting the formation of Al-organic matter complexes.
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Wright, M. D. "Pleistocene deposits of the South Wales Coalfield and their engineering significance." Geological Society, London, Engineering Geology Special Publications 7, no. 1 (1991): 441–48. http://dx.doi.org/10.1144/gsl.eng.1991.007.01.41.
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AbstractThe importance of glaciation in the modification of landscape in the South Wales coalfield has long been acknowledged. The effect of periglacial conditions has never been fully assessed, even though these are of enormous relevance to the geomorphology and to the prediction of the engineering characteristics of the superficial deposits.Examination of field relationships and sedimentology has proved the presence, in valley-floors, of glacial lodgement tills, meltout tills and associated water-lain deposits. On lower valley-sides, however, a large proportion of the drift has moved downslope by gelifluction or as mudflows. These redistributed sediments contain silt bands which can cause side-slope collapse in cuttings. They also extend over valley-floors and may conceal glaciolacustrine deposits which can contain water at artesian pressures.Higher valley-side slopes and hilltops show extensive modification by periglacial processes, and there are solifluction terraces and nivation hollows. A good understanding of depositional processes is required for any investigation of slope stability.
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Gao, B., X. Wen, H. Guan, M. Knížek, and J. Žďárek. "Distribution and attack behaviour of the red turpentine beetle, Dendroctonus valens, recently introduced to China." Journal of Forest Science 51, No. 4 (January 10, 2012): 155–60. http://dx.doi.org/10.17221/4554-jfs.
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The red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Scolytidae), was found for the first time in China in Yangcheng and Xinshui counties, Shanxi province in 1998, and in Hebei province in 1999. The beetle mostly attacks the oil pine Pinus tabulaeformis Carriére. By 2003 the beetle was found in 85 counties of three provinces in north China and the area of infested pine forests covered more than 700,000 ha. The elevation above sea level of forests infested is more than 800 m. The beetles most frequently attack trees on hilltops and at the forest edge, fewer attacks occur in the centre of the stand. This correlates with the damage done to the trees by wind or man. Weak and dying trees are more vulnerable to attack than healthy ones. The most attractive breeding sites are fresh stumps. The population density of the beetles is higher in the forests on northern slopes than on southern slopes. Most of the bores in the trunk are less than 0.5 m above ground; the galleries are found also on roots.
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Gore, Damian B. "Blanketing snow and ice; constraints on radiocarbon dating deglaciation in East Antarctic oases." Antarctic Science 9, no. 3 (September 1997): 336–46. http://dx.doi.org/10.1017/s0954102097000412.
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Radiocarbon dating of marine, lacustrine or terrestrial biogenic deposits is the main technique used to determine when deglaciation of the oases of East Antarctica occurred. However, at many of the oases of East Antarctica, including the Schirmacher Oasis, Stillwell Hills, Amery Oasis, Larsemann Hills, Taylor Islands and Grearson Oasis, snow and ice presently forms extensive blankets that fills valleys and some lake basins, covers perennial lake ice and in places overwhelms local topography to form ice domes up to hundreds of square kilometres in area. Field observations from Larsemann Hills and Taylor Islands suggest that under these conditions, terrestrial and lacustrine biogenic sedimentation is neither widespread nor abundant. If similar conditions prevailed in and around the oases immediately following retreat of the ice sheet, then a lengthy hiatus might exist between deglaciation and the onset of widespread or abundant biogenic sedimentation. As a result, radiocarbon dating might be a clumsy tool with which to reconstruct deglaciation history, and independent dating methods that record emergence of the hilltops from the continental ice must be employed as well.
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Smith, R. B., P. Schafer, D. J. Kirshbaum, and E. Regina. "Orographic Precipitation in the Tropics: Experiments in Dominica." Journal of the Atmospheric Sciences 66, no. 6 (June 1, 2009): 1698–716. http://dx.doi.org/10.1175/2008jas2920.1.
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Abstract The “natural laboratory” of mountainous Dominica (15°N) in the trade wind belt is used to study the physics of tropical orographic precipitation in its purest form, unforced by weather disturbances or by the diurnal cycle of solar heating. A cross-island line of rain gauges and 5-min radar scans from Guadeloupe reveal a large annual precipitation at high elevation (7 m yr−1) and a large orographic enhancement factor (2 to 8) caused primarily by repetitive convective triggering over the windward slope. The triggering is caused by terrain-forced lifting of the conditionally unstable trade wind cloud layer. Ambient humidity fluctuations associated with open-ocean convection may play a key role. The convection transports moisture upward and causes frequent brief showers on the hilltops. The drying ratio of the full air column from precipitation is less than 1% whereas the surface air dries by about 17% from the east coast to the mountain top. On the lee side, a plunging trade wind inversion and reduced instability destroys convective clouds and creates an oceanic rain shadow.
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Sheridan, Peter, Simon Vosper, and Samantha Smith. "A Physically Based Algorithm for Downscaling Temperature in Complex Terrain." Journal of Applied Meteorology and Climatology 57, no. 8 (August 2018): 1907–29. http://dx.doi.org/10.1175/jamc-d-17-0140.1.
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AbstractRecent improvements to an algorithm to be used operationally for downscaling screen temperatures from numerical weather prediction models are described. Testing against very high resolution dynamically downscaled screen temperatures and intensive field measurements taken during the Cold-Air Pooling Experiment (COLPEX) is performed. The improvements are based on a physical understanding of the processes involved in the formation of cold-air pools (CAPs) that is informed by recent research. The algorithm includes a parameterization of sidewall sheltering effects that lead to lower temperatures in valley-bottom CAPs on clear, calm nights. Advection and adjustment over exposed hilltops results in higher screen temperatures than on flat ground but lower temperatures relative to the free air above the valley at the same elevation, and a treatment of this effect has also been developed. These processes form the major contributions to the often dramatic small-scale variations in temperature in complex terrain in stable boundary layer conditions, even when height variation is fairly shallow. The improvements result in qualitatively better reproduction of subgrid temperature patterns in complex terrain during CAPs. Statistical forecast errors are subsequently improved.
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Ferreira-Júnior, W. G., A. F. Silva, C. E. G. R. Schaefer, J. A. A. Meira Neto, A. S. Dias, M. Ignácio, and M. C. M. P. Medeiros. "INFLUENCE OF SOILS AND TOPOGRAPHIC GRADIENTS ON TREE SPECIES DISTRIBUTION IN A BRAZILIAN ATLANTIC TROPICAL SEMIDECIDUOUS FOREST." Edinburgh Journal of Botany 64, no. 2 (July 2007): 137–57. http://dx.doi.org/10.1017/s0960428607000832.
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AbstractThis study investigated the effect of environmental variables such as soil class, soil water availability, topography and slope on spatial distribution patterns of tree species in a Brazilian Seasonal Semideciduous Forest area. Floristic and structural data for a tree community were obtained by sampling 100 plots 10 × 10 m in which every tree with trunk diameter (dbh) ⩾ 4.77 cm at 130 cm above ground level was sampled. The area under study showed a marked soil gradient, directly associated with the topography: flat hilltops with Al3+-rich Dystric Latosols give way to steep colluvial slopes with shallower and more Dystric Cambic Latosols without Al3+, changing over, at the bottom of the hollows, to Epieutrophic Cambisols richer in nutrients. The floristic-sociological parameters analysed for the soil habitats did not differ statistically from each other. The diversity and equability indices were 3.6 and 0.84, 3.48 and 0.85, 3.49 and 0.84 for the Dystric Latosol, Dystric Cambic Latosol and Epieutrophic Cambisol, respectively. The soil variables (related to the fertility and texture) and the soil water regime (drainage) were probably the principal factors determining the spatial distribution patterns of tree species in the forest.
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Carrión-Mero, Paúl, Alicia Ayala-Granda, Sthefano Serrano-Ayala, Fernando Morante-Carballo, Maribel Aguilar-Aguilar, Miguel Gurumendi-Noriega, Nataly Paz-Salas, Gricelda Herrera-Franco, and Edgar Berrezueta. "Assessment of Geomorphosites for Geotourism in the Northern Part of the “Ruta Escondida” (Quito, Ecuador)." Sustainability 12, no. 20 (October 14, 2020): 8468. http://dx.doi.org/10.3390/su12208468.
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The relevant geomorphological characteristics of territory represent an essential part of its natural heritage. They are also an asset to be exploited for stimulating socio-economic development. The “Ruta Escondida” in Ecuador constitutes a historical place full of culture and landscapes that have been shaped over time by geological and geomorphological processes. Among the geomorphological features of the study area, volcanic cones, hilltops, terraces, foothills and glacial valleys stand out. The aims of this work were: (1) to characterize 18 places of geomorphological interest, located in the northern part of the Ruta Escondida and (2) to propose alternatives (geotourism) to contribute to the local development of the area. The applied methodology included: (1) the compilation of geomorphological elements; (2) the assessment of geomorphosites using the Inventario Español de Lugares de Interés Geológico (IELIG) method and (3) a strengths–opportunities–weaknesses–threats analysis of the contribution and influence of geomorphosites in the development of the study area. With this work, it was possible to determine that all the analyzed geomorphological sites have a high and very high interest. The strengths, weaknesses, opportunities, and threats (SWOT) analysis revealed that the geomorphosites could provide significant added value to the development of geotourism on the route, complementing the already known cultural and historical attractions.
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Berg, Sonja, Martin Melles, Damian B. Gore, Sergei Verkulich, and Zina V. Pushina. "Postglacial evolution of marine and lacustrine water bodies in Bunger Hills." Antarctic Science 32, no. 2 (February 27, 2020): 107–29. http://dx.doi.org/10.1017/s0954102019000476.
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AbstractUnglaciated coastal areas in East Antarctica provide records of past ice sheet and glacier fluctuations and subsequent environmental conditions. In this paper we review lithological, geochemical, diatom and radiocarbon data from sediment records from inland and epishelf lakes in Bunger Hills, East Antarctica. While some hilltops were unglaciated during the Last Glacial Maximum, till deposits in lake basins indicate infilling by glacier ice prior to the Holocene. Proglacial sedimentation occurred in lakes during the early Holocene. Around 9.6 ka bp, deposition of marine sapropel started under relatively warm climate conditions. Inland lakes were affected by high clastic input from meltwater runoff until c. 7.9 ka bp, when deposition became highly organic and biogenic proxies indicate a period of cooler conditions. Epishelf lakes experienced a decrease in water exchange with the ocean and increased freshwater input around 7.7 ± 0.2 ka bp and after 2.2 ka bp. This probably resulted from grounding line advances of the bounding glaciers, which could be either controlled by relative sea level (RSL) lowering and/or climate-driven glacier dynamics. The absence of marine sediments in the postglacial record of Algae Lake indicates that Holocene RSL probably reached a maximum at or below 10 m above present sea level.
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Lin, Jessica, Seulgi Moon, Alan Yong, Lingsen Meng, and Paul Davis. "Length‐Scale‐Dependent Relationships between VS30 and Topographic Slopes in Southern California." Bulletin of the Seismological Society of America 109, no. 6 (September 17, 2019): 2614–25. http://dx.doi.org/10.1785/0120190076.
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Abstract In engineering seismology, the time‐averaged shear‐wave velocity (VS) of the upper 30 m of the crust (VS30) is the primary parameter used in ground‐motion models to predict seismic site effects. VS30 is typically derived from in situ recordings of VS, although proxy‐based approaches (using geologic and/or geomorphometric classifications) are provisionally adopted when measurement‐based VS30 are sparse or not readily available. Despite the acceptance of proxy approaches, there are limited studies that examine the empirical relationships between VS30 and topographic attributes measured from various length scales and different resolutions of the digital elevation model. In this study, we examine the relationships between compiled VS30 measurements from 218 sites in southern California and topographic metrics of slope and relief measured over various length scales. We find that the correlations between topographic metrics and VS30 are weak but statistically significant. The correlations are improved when topographic slopes and relief are measured over length scales longer than typical hillslopes and VS30 sites are separated by different geologic groups. This is likely because VS30, especially on the rock sites, is better reflected in topographic metrics that capture large‐scale topographic relief, as well as landscape positions such as hilltops and valley bottoms.
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Wilmsen, Edwin N. "MYTHS, GENDER, BIRDS, BEADS: A READING OF IRON AGE HILL SITES IN INTERIOR SOUTHERN AFRICA." Africa 84, no. 3 (July 23, 2014): 398–423. http://dx.doi.org/10.1017/s0001972014000370.
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ABSTRACTHomologous origin myths concerning the Tsodilo Hills in north-western Botswana, Polombwe hill at the southern tip of Lake Tanganyika in Zambia and Kaphiri-Ntiwa hill in northern Malawi are examined. Parallels are drawn between the myths, where, in the process of creation, a primal pair in undifferentiated space and time passes through a series of liminal states, thereby bringing structure to the landscape and legitimacy to society in Iron Age Central and Southern Africa. These myths narrate the instituting of social legitimacy in their respective societies based on a resolution of the inherent contradiction between the concepts of authority and power, lineage and land. The structure of rights to possession of land is examined, and the text considers the role of sumptuary goods such as glass beads and metonymic signifiers such as birds within this structure. This study examines the prominence of hilltops as the residence of paranormal power and its association with human authority, and relates this to the archaeological interpretation of the Iron Age site Nqoma (Tsodilo Hills); this is compared with Bosutswe (eastern Botswana), Mapungubwe (Shashe-Limpopo basin), and the Shona Mwari myth recorded by Frobenius as used by Huffman in his analysis of Great Zimbabwe.
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Mihu-Pintilie and Nicu. "GIS-based Landform Classification of Eneoli thic Archaeological Sites in the Plateau-plain Transition Zone (NE Romania): Habitation Practices vs. Flood Hazard Perception." Remote Sensing 11, no. 8 (April 15, 2019): 915. http://dx.doi.org/10.3390/rs11080915.
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The landforms of the Earth’s surface ranging from large-scale features to local topography are factors that influence human behavior in terms of habitation practices. The ability to extract geomorphological settings using geoinformatic techniques is an important aspect of any environmental analysis and archaeological landscape approach. Morphological data derived from DEMs with high accuracies (e.g., LiDAR data), can provide valuable information related to landscape modelling and landform classification processes. This study applies the first landform classification and flood hazard vulnerability of 730 Eneolithic (ca. 5000–3500 BCE) settlement locations within the plateau-plain transition zone of NE Romania. The classification was done using the SD (standard deviation) of TPI (Topographic Position Index) for the mean elevation (DEV) around each archaeological site, and HEC-RAS flood hazard pattern generated for 0.1% (1000 year) discharge insurance. The results indicate that prehistoric communities preferred to place their settlements for defensive purposes on hilltops, or in the close proximity of a steep slope. Based on flood hazard pattern, 8.2% out of the total sites had been placed in highly vulnerable areas. The results indicate an eco-cultural niche connected with habitation practices and flood hazard perception during the Eneolithic period in the plateau-plain transition zone of NE Romania and contribute to archaeological predictive modelling.
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Simon, Zeno, Mario L. Baldasso, Adejalmo F. Gazen, and Juan C. Aguirre. "Comparison between a Perforated Pipe and a Fixed Sprinkler System for Land Disposal of Treated Petrochemical Effluent." Water Science and Technology 19, no. 8 (August 1, 1987): 107–19. http://dx.doi.org/10.2166/wst.1987.0049.
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At SITEL – the integrated effluent treatment system of Pólo Petroquímico do Sul (South Petrochemical Complex, Triunfo, Brazil) – the tertiary-treated effluent is disposed of on land at an average hydraulic application rate of 140 m3/ha.day. Two subsystems have been installed in order to minimize the devastation of indigenous vegetation during the construction phase, aiming also at investigating the cheaper processes to be adopted when expansions become necessary. The first subsystem consists of a network of perforated PVC pipes which distribute the effluent over a forested area through an arrangement compatible with the local basin divides. It is fed by six submersible centrifugal pumps operating at moderate heads (ca. 30 m H2O). The second subsystem comprises high capacity rotating impact sprinklers fixed on hilltops covered predominantly by grasses. It is fed by two dry well centrifugal pumps operating at higher heads. The design criteria for both systems stem from a “zero runoff” legal requirement applicable within the limits of the 100 ha disposal site. The two subsystems are compared as regards technical aspects and economics. Removal efficiencies are presented. Capital and running costs related to pumping stations, mains, distribution networks, ancillary equipment and appurtenances, power consumption, maintenance, operation, materials etc. are compared and discussed. Functions and indexes that may prove useful in feasibility studies for similar systems are presented.
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Kisan, Mali Vijay, Pathak Khanindra, Tiwari Kamlesh Narayan, and Tripathy Swarup Kumar. "Remote sensing and GIS based assessment of soil erosion and soil loss risk around hill top surface mines situated in Saranda Forest, Jharkhand." Journal of Water and Climate Change 7, no. 1 (June 15, 2015): 68–82. http://dx.doi.org/10.2166/wcc.2015.100.
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The quantitative analysis of soil erosion changes over 7 years due to mining operations in two neighboring hilltops in West-Singhbhum District, Jharkhand, are reported. CartoSat-1, ETM+ and LISS-IV satellites' data provided spatial inputs in Universal Soil Loss Equation (USLE) and Morgan, Morgan and Finney method (MMF) models, which were used to predict the average annual soil erosion during the period of 2001–2008 in a geographic information system (GIS), in six distinct classes. In the comparative analysis of the 7-year period, the MMF model revealed a lower coefficient of variation 0.71 (2001) and 0.84 (2008) in predicted average annual soil loss, which increased by 16% (81.3–94.2 t ha−1yr−1), whereas in the case of USLE, the coefficients of variation were 3.88 (2001) and 1.94 (2008), with an increase of 61% (48.56–78.38 t ha−1yr−1). The correlation coefficient of these models was 0.1 (2001) and 0.36 (2008), which shows that both models predicted significantly differently as a result of the different factors considered. Overall, the MMF model predicted a higher soil erosion rate but less variation than USLE. Both models showed soil erosion rates were drastically increased by anthropogenic activities in the area, hence careful consideration is needed. The same sensor and imaging data could not be maintained. Correction of errors may reduce erosion, but it will still remain significant for future planning.
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Koroleva, N. E. "Treeless plant communities of the East Murman shore (Kola peninsula, Russia)." Vegetation of Russia, no. 9 (2006): 20–42. http://dx.doi.org/10.31111/vegrus/2006.09.20.
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A phytosociological survey of the Barents Sea coastal plant communities according to Braun-Blanquet approach is presented. Ass. Honckenyo diffusae—Elymetum arenarii (Regel 1928) R. Tx. 1966. is described on the sand beach. Halophillous vegetation is fragmented and ascribed to the community type Stellaria humifusa—Triglochin palustre. Tall herb meadows on the shore are described as ass. Tripleurospermo—Festucetum arenariae ass. nov. Mesic and moist meadows on the sea-exposed slopes are described as ass. Polygono vivipari—Thalictretum alpini (Kalliola 1939) stat. nov. Ass. Geranietum sylvatici Nordh.1943 includes meadows along springs and brooks, ass. Rumici—Salicetum lapponi Dahl 1957 combines meadows with willow shrub layer. Heath vegetation of the marine terrains and low hills is presented by ass. Arctostaphylo alpinae—Empetretum hermaphroditi (Zinserling 1935) Koroleva 1994, and heathlands on the hilltops belong to the Loiseleurio—Diapensietum (Fries 1913) Nordh. 1943 subass. typicum и salicetosum nummulariae subass. nov. Stands of ass. Phyllodoco—Vaccinietum myrtilli Nordh. (1928) 1943 are common in the snow-protected habitats. Snow-bed communities are described as ass. Veratro lobeliani—Salicetum herbaceae ass. nov. Paludified heathlands are described as ass. Rubo chamaemori—Caricetum rariflorae (Regel 1923) stat. nov. Sloping fens belong to ass. Drepanoclado revolventis—Trichophoretum cespitosi Nordh. 1928. The syntaxa spectrum of the area investigated shows close affinities to the low arctic tundra subzone as well as to the coastal vegetation of the subarctic region.
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Foss, Clive. "Strobilos and Related Sites." Anatolian Studies 38 (December 1988): 147–74. http://dx.doi.org/10.2307/3642848.
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In the Byzantine period, urban life in Anatolia underwent a decay in which ancient cities shrank behind reduced circuits of walls or withdrew to the fortified hilltops whence they had descended in the Hellenistic age. Even the greatest city of the empire, Constantinople, saw a drastic diminution of population and resources, abandonment of its ancient public works and services, and consequent transformation from a classical to a medieval city. These changes began with the devastating invasions of Persians and Arabs in the seventh century. Sources reveal little about Anatolia between the early seventh and mid-ninth century, a true dark age, but the evidence of archaeology often makes it possible to visualize conditions at the time.The Byzantines, whose empire long survived these troubles, generally occupied existing sites in Asia Minor where their ruins are superimposed on those of the Romans or earlier cultures. In only a few instances, usually occasioned by the needs of defence or of a militarized administration, were new sites founded. Although the Dark Ages were not a propitious time for urban development, some new towns did come into existence or prominence. Few of them have been studied. Strobilos on the Carian coast, therefore, is of some potential interest as an example of a Byzantine town which first appears in the historical record in the eighth century, and whose remains have been preserved.
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Stokes, Martin, Anne Mather, Angel Rodes, Samantha Kearsey, and Shaun Lewin. "Anatomy, Age and Origin of an Intramontane Top Basin Surface (Sorbas Basin, Betic Cordillera, SE Spain)." Quaternary 1, no. 2 (August 24, 2018): 15. http://dx.doi.org/10.3390/quat1020015.
Full textAbstract:
Collisional mountain belts commonly develop intramontane basins from mechanical and isostatic subsidence during orogenic development. These frequently display a relict top surface, evidencing a change interval from basin infilling to erosion often via capture or overspill. Such surfaces provide markers that inform on orogenic growth patterns via climate and base level interplay. Here, we describe the top surface from the Sorbas Basin, a key intramontane basin within the Betic Cordillera (SE Spain). The surface is fragmentary comprising high elevation hilltops and discontinuous ridges developed onto the variably deformed final basin infill outcrop (Gochar Formation). We reconstruct surface configuration using DEM interpolation and apply 10Be/26Al cosmonuclides to assess surface formation timing. The surface is a degraded Early Pleistocene erosional pediment developed via autogenic switching of alluvial fan streams under stable dryland climate and base level conditions. Base-level lowering since the Middle Pleistocene focused headwards incision up interfan drainages, culminating in fan head capture and fan morphological preservation within the abandoned surface. Post abandonment erosion has lowered the basin surface by 31 m (average) and removed ~5.95 km3 of fill. Regional basin comparisons reveal a phase of Early Pleistocene surface formation, marking landscape stability following the most recent Pliocene-Early Pleistocene mountain building. Post-surface erosion rate quantification is low and in accordance with 10Be denudation rates typical of the low uplift Betic Cordillera.
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MANU, SHIIWUA, INAOYOM SUNDAY IMONG, and WILL CRESSWELL. "Bird species richness and diversity at montane Important Bird Area (IBA) sites in south-eastern Nigeria." Bird Conservation International 20, no. 3 (January 11, 2010): 231–39. http://dx.doi.org/10.1017/s0959270909990311.
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SummaryThe mountains of south-eastern Nigeria are a western extension of the Cameroon mountain range, which is classified as an endemic bird area (EBA). Unlike its eastern extension in Cameroon, most of the ornithological surveys in the western extension of the Cameroon highlands in Nigeria have produced only limited checklists and inventories. There is a clear need for quantitative baseline data so that conservation problems can be identified. Twenty line transects covering a total transect length of 28.8 km were used to survey five sites (Afi Mountain Wildlife Sanctuary, Oban Division and Okwangwo Division of Cross River National Park, Sankwala Mountains and Mbe Mountains) in the westernmost extension of the Cameroon Mountains EBA in south-eastern Nigeria. Vegetation measurements were taken to control for the potential confounding effect of variation in vegetation density and structure on detectability of birds between sites. The 193 bird species recorded in Afi, 158 in Sankwala, 124 in Oban, 100 in Mbe and 73 in Okwangwo Division included most of the Cameroon highlands restricted range species. The results show that the mountains of south-eastern Nigeria are important parts of the Cameroon EBA, particularly Afi Mountain Wildlife Sanctuary. However these sites are threatened by fire and livestock grazing on the hilltops, shifting agriculture on the hillsides and lowlands, and logging for timber in some parts, as well as wildlife hunting for bushmeat.
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Chias, P., and T. Abad. "Impact Assessment of the Renewable Energies in the Cultural Heritage: the Case of the Way of St. James in Spain." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-5 (June 6, 2014): 165–71. http://dx.doi.org/10.5194/isprsarchives-xl-5-165-2014.
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Medieval town centres and landscapes along the Way of St. James are being affected by renewable energy sources at the architectural, urban and territorial scales. The impact is not only visual, but thermal, accoustic and electromagnetic. Visual impact of solar photovoltaic power plants – which are placed over traditional crops close to the urban borders –, and also wind farms located at the hilltops, are sometimes remarkable. Solar photovoltaic modules are integrated into ancient roofs, and small scale wind turbines are taking up the ancient urban spaces. Among other effects on animal life and vegetation, the rise in temperature, radioelectric interferences, as well as changes in the traditional land uses are noticeable, and a deep analysis is needed. Our main target is to define an integrated methodology which considers all these effects. As a part of our project premises, we work with Open Source programs. We obtained a digital terrain model – 25 m spatial resolution –, and from Corine Land Cover images we got different raster files according to our research targets. Databases where implemented from both remote sensing and measures obtained directly in the field work. We applied GIS based multicriteria decision analysis and weighted linear combination, and then we adapted GRASS tools for a better usability. Our case studies are particularly interesting due to their situation along the Spanish Way of St. James, which is an itinerary named one of UNESCO's World Heritage Sites.
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Lajeunesse, Patrick, and Michel Allard. "The Nastapoka drift belt, eastern Hudson Bay: implications of a stillstand of the QuebecLabrador ice margin in the Tyrrell Sea at 8 ka BP." Canadian Journal of Earth Sciences 40, no. 1 (January 1, 2003): 65–76. http://dx.doi.org/10.1139/e02-085.
Full textAbstract:
During deglaciation of eastern Hudson Bay, the western margin of the QuébecLabrador sector of the Laurentide Ice Sheet came to a stillstand about 8 14C ka BP along the Nastapoka Hills, a series of topographic highs along the bay. These hills are the northward continuation of the eastern Hudson Bay cuesta system. It left a drift belt consisting of ice-contact submarine fans along the western slopes of the hills, small frontal moraines on hilltops, and grounding-line deposits on sills between the hills. Geomorphological, sedimentary, and radiometric evidence suggest that the stillstand responsible for deposition of the Nastapoka drift belt was either entirely or partly synchronous with the deposition of the Sakami moraine farther south. There was a period when these two morainic systems marked a continuous ice margin. These stillstands occurred due to reduction of ablation at the ice margin. In the Nastapoka Hills, ablation slowed down when the ice margin was anchored on higher relief and stood at a regional break of slope that grounded the ice margin and reduced water depth at the ice terminus, therefore, putting an end to intensive calving. In eastern James Bay and southeastern Hudson Bay, stabilization of the ice margin was caused by a reequilibrium of the ice terminus after a rapid drop of water level due to the drainage of Glacial Lake Ojibway. The new data improves the resolution of the position ice margin in eastern Hudson Bay at 8 ka BP.
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Sagona, Antonio, Mustafa Erkmen, Claudia Sagona, and Ian Thomas. "Excavations at Sos Höyük, 1995: Second Preliminary Report." Anatolian Studies 46 (December 1996): 27–52. http://dx.doi.org/10.2307/3642998.
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Archaeological investigations this year at Sos Höyük, carried out by the University of Melbourne and Erzurum Museum, took place in the summer, between 2 June and 3 August. The aims for the 1995 season included activities both on the mound and off-site. Among the former objectives, was the need to expose further the Medieval settlement on the summit of the mound, and the burnt building of the Hellenistic period in trenches L14 and L13. Excavation was also required in the lower northeast trenches to clarify the depositions of the late third to second millennium B.C. In addition to these largely horizontal operations, we commenced an independent vertical sounding in J14 to obtain a immediate guide to the sequence of Iron Age deposits.The intensive field survey of the site environs continued, as did the search for the obsidian source in the hilltops around Pasinler. A detailed palaeoecological study of the region was initiated this year. Information from promising pollen cores taken at various altitudes in the Kargapazarı Dağları, the mountain range immediately to the north of the site, will no doubt complement the faunal and botanical data from the excavations. We also conducted a magnetic survey of the ancient cemeteries surrounding the site to better define their boundaries, but human and animal disturbance often made it difficult to discriminate between burials, pits and burrows of comparable magnetic intensity. Finally, there was a concerted effort to organize and establish a new exhibition at Erzurum Museum covering the campaigns at both Büyüktepe Höyük and Sos Höyük.
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Loiselle, Bette A., John G. Blake, Renata Durães, T. Brandt Ryder, and Wendy Tori. "Environmental and Spatial Segregation of Leks Among Six Co-Occurring Species of Manakins (Pipridae) in Eastern Ecuador." Auk 124, no. 2 (April 1, 2007): 420–31. http://dx.doi.org/10.1093/auk/124.2.420.
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AbstractEnvironmental correlates and geographic spacing of leks were compared for six species of manakins (Pipridae) on two 100-ha study plots in eastern Ecuador. The “hotspot” hypothesis of lek evolution suggests that males should aggregate where females are most likely to be encountered. For ecologically similar species that co-occur at a site, leks are predicted to be clustered in space and, thus, to overlap in macroscale environmental characteristics. The geographic spacing and environmental characteristics of lek sites we observed were inconsistent with the hotspot hypothesis for lek evolution. In general, little geographic overlap occurred among leks, and geographic spacing of leks among heterospecifics more closely fit a regular than a clumped pattern. Further, environmental conditions of leks varied among species with respect to elevation and topography. Leks of some species were more likely to occur on hilltops or ridge tops (e.g., Machaeropterus regulus, Pipra erythrocephala), whereas others appeared to prefer highly dissected drainages (e.g., P. pipra), relatively flat terrain near streams (e.g., Chiroxiphia pareola), or seasonally inundated forests (e.g., P. filicauda). Using randomly placed leks, we found evidence that certain lek environments may be limited, which is consistent with observed levels of population abundances on the two plots. Such environmental limits may constrain lek placement and size. Further study is needed to determine the reproductive implications of placing leks in apparently suboptimal environments, though such compromises may reflect males making the best of a bad situation.Segregación Ambiental y Espacial de las Asambleas de Cortejo Entre Seis Especies Simpátricas de Saltarines (Pipridae) en el Oriente de Ecuador
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MENDOZA B., Martin Alfonso, Angélica NAVARRO-MARTÍNEZ, Carl W. MIZE, Gerson Daniel ALDUCIN CHÁVEZ, and Patricia NEGREROS-CASTILLO. "Tendencias minimalistas en la gestión de los bosques tropicales mexicanos: motivaciones y experiencias." BOIS & FORETS DES TROPIQUES 348 (June 22, 2021): 29–36. http://dx.doi.org/10.19182/bft2021.348.a31913.
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Tropical timber regions across the world share common problems such as degradation and poor regeneration after timber harvesting. Traditional Mayan land management through slash and burn is now recognized as an effective way of renewing forest stands in multispecies tropical forests. The practice of slash and burn for forest management in Mexico has led to area regulation, which has made land value a convenient means of assessing alternative forest plans. The use of expected land value as a performance indicator shifts the manager's attention from managing a species mix to balancing financial tradeoffs between liquidation or retention of the standing biomass. Since the forest-wide residual stock is so large, land value overrides the importance of revenue from timber sales. Several forest management methods along these lines have appeared in tropical regions of Mexico over a thirty-year time span and represent a patrimonial system of forest management (PS). The gradual innovation generated by PS is described here, as well as examples of PS practices. PS methods today provide stewardship for a total of 155,814 ha in different parts of Mexico. PS performance will become evident in the long run; in the meantime, the embrace of PS by private landowners and regulatory institutions is equated with a positive, independent opinion about PS design. The Mexican experience suggests pathways for rational management of all types of forests. PS features that are worth replicating are, for instance, the inclusion of disturbance patterns as factors in decision making, as well as the use of specific silvicultural regimes for roads, woodlands, closed forests, hilltops, swamps, riparian zones, clearings and forest edges.
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Thaler, Evan A., Isaac J. Larsen, and Qian Yu. "The extent of soil loss across the US Corn Belt." Proceedings of the National Academy of Sciences 118, no. 8 (February 16, 2021): e1922375118. http://dx.doi.org/10.1073/pnas.1922375118.
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Soil erosion in agricultural landscapes reduces crop yields, leads to loss of ecosystem services, and influences the global carbon cycle. Despite decades of soil erosion research, the magnitude of historical soil loss remains poorly quantified across large agricultural regions because preagricultural soil data are rare, and it is challenging to extrapolate local-scale erosion observations across time and space. Here we focus on the Corn Belt of the midwestern United States and use a remote-sensing method to map areas in agricultural fields that have no remaining organic carbon-rich A-horizon. We use satellite and LiDAR data to develop a relationship between A-horizon loss and topographic curvature and then use topographic data to scale-up soil loss predictions across 3.9 × 105 km2 of the Corn Belt. Our results indicate that 35 ± 11% of the cultivated area has lost A-horizon soil and that prior estimates of soil degradation from soil survey-based methods have significantly underestimated A-horizon soil loss. Convex hilltops throughout the region are often completely denuded of A-horizon soil. The association between soil loss and convex topography indicates that tillage-induced erosion is an important driver of soil loss, yet tillage erosion is not simulated in models used to assess nationwide soil loss trends in the United States. We estimate that A-horizon loss decreases crop yields by 6 ± 2%, causing $2.8 ± $0.9 billion in annual economic losses. Regionally, we estimate 1.4 ± 0.5 Pg of carbon have been removed from hillslopes by erosion of the A-horizon, much of which likely remains buried in depositional areas within the fields.
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Matsuda, Tomohiro. "Hilltop curvatons." Physics Letters B 659, no. 4 (January 2008): 783–88. http://dx.doi.org/10.1016/j.physletb.2007.12.008.
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Boubekeur, Lotfi, and David H. Lyth. "Hilltop inflation." Journal of Cosmology and Astroparticle Physics 2005, no. 07 (July 19, 2005): 010. http://dx.doi.org/10.1088/1475-7516/2005/07/010.
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Souza, Priscila Bezerra de, João José Lelis, Carlos Ernesto Gonçalves Reynaud Schaefer, Agostinho Lopes de Souza, and João Augusto Alves Meira Neto. "Distribution of tree species in a geomorphological and pedological gradient of submontane semidecidual seasonal forest in the vicinity of Rio Doce state park, Minas Gerais." Revista Árvore 36, no. 4 (August 2012): 707–18. http://dx.doi.org/10.1590/s0100-67622012000400012.
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The objective of this study was to test the hypothesis that the distribution of tree species in a fragment of submontane seasonal semideciduous forest, a buffer zone in the Parque Estadual do Rio Doce, Minas Gerais, is influenced by geomorphological and weather and soil variables, therefore it can represent a source of information for the restoration of degraded areas where environmental conditions are similar to those of the study area. A detailed soil survey was conducted in the area by sampling three soil profiles per slope segment, totaling 12 profiles. To sample the topsoil, four composite samples were collected from the 10-20 cm layers in each topographic range totaling 16 composite samples. In the low ramp and the lower and upper concave slopes, the texture ranged from clay to sandy-clay. The soil and topographic gradient was characterized by changes in the soil physical-chemical properties. The soil in the 10-20 cm sampled layer was sandier, slightly more fertile and less acid in the low ramp than the clayer soil, nutrient-poor and highly acid soil at the top. The soil conditions in the lower and upper slope of the sampled layers, in turn, were intermediate. The P levels were limiting in all soils. The species distribution along the topographic gradient was associated with variations in chemical fertility, acidity and soil texture. The distribution of Pera leandri, Astronium fraxinifolium, Pouteria torta, Machaerium brasiliense and Myrcia rufipes was correlated with high aluminum levels and to low soil fertility and these species may be indicated for restoration of degraded areas on hillsides and hilltops in regions where environmental conditions are similar. The distribution of Pouteria venosa, Apuleia leiocarpa and Acacia polyphylla was correlated with the less acid and more fertile soil in the environment of the low ramps, indicating the potential for the restoration of similar areas.
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ALMEIDA, L. M., G. L. WERNECK, S. CAIRNCROSS, C. M. COELI, M. C. E. COSTA, and P. E. COLETTY. "The epidemiology of hepatitis A in Rio de Janeiro: environmental and domestic risk factors." Epidemiology and Infection 127, no. 2 (October 2001): 327–33. http://dx.doi.org/10.1017/s0950268801005945.
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A serological study of hepatitis A was carried out in low-income areas scheduled for a major sanitation programme in Rio de Janeiro, Brazil. Blood spots were collected by finger puncture and transported on filter paper, and total antibodies to hepatitis A virus were detected by ELISA. Households were also interviewed to collect information on their environmental conditions and socio-economic status. A generalized linear model using a complementary log–log function was fitted to the data, using the logarithm of age as an explanatory variable to derive adjusted rate ratios (RR). The risk of infection was greater among households with 2–3 members per room (RR = 1·4; 95% CI = 1·04–1·8) or more than three per room (RR = 1·5; 95% CI = 1·2–2·0). People living on hilltops (RR = 1·5; 95% CI = 1·02–2·2), near to open sewers (RR = 1·2; 95% CI = 1·03–1·5) or lacking a kitchen (RR = 1·4; 95% CI = 1·08–1·9) were also at greater risk than others. The number of taps and water-using fittings in the house was associated with a protective effect (RR = 0·9 for each tap; 95% CI = 0·9–0·98). A significant protective association was found with maternal education but not with gender or household income. The results do not suggest a strong association with water quality. Ownership of a ceramic water filter was associated with a protective effect on the margin of significance, but the practice of boiling drinking-water was not, nor was the type of water source used. The results suggest that that the risk of infection with hepatitis A is determined by environmental variables in the domestic and public domains.