56 research outputs found
Geomorphology and geomorphological responses to climate change in the interior of sub-Antarctic Marion Island
The influence of climate change on the geomorphology of the interior of Marion Island (above 750m a.s.l.) is investigated as climatic amelioration is thought to be responsible for the observed rapid melt out of the summit regions. Records have shown that the climate on Marion Island is warming and, as it represents a maritime periglacial environment characterised by small seasonal temperature ranges and steep temperature profiles, it is particularly sensitive to climate change. Marion Island is, therefore, an ideal location to address the poor understanding of periglacial environments in the Southern Circumpolar Region in the context of environmental conditions governing permafrost, seasonally frozen ground, and frost processes. To ascertain the influence of climatic amelioration on the geomorphology of Marion Island’s interior, thermokarst, periglacial, and rudimentary aeolian features were identified and mapped. Geomorphological features were documented to determine the extent of landscape response to climate change in the island’s interior. In addition, identification and mapping of geomorphological features were, in some cases, used to provide evidence for the previous existence of permafrost. Ground temperatures were also monitored to determine the present state and possible existence of permafrost above 750m a.s.l. Landscape development in the certain areas of the interior of Marion Island where glacial ice persists beneath sediment (scoria) and where permafrost previously existed has resulted in the manifestation of thermokarst features and the creation of a unique undulating topography. In parts of the study area, thermal erosion and subsidence of the thermokarst are identified as processes that are important agents of landscape evolution. Thermokarst processes, indicative of climate change are, however, limited to areas where buried glacial ice persists and permafrost existed. Thermokarst features studied were also noted to be ephemeral and easily destroyed through erosion by wind and water. Aeolian erosion, in particular, has a significant influence on thermokarst as the interior of the island represents a polar desert where almost no vegetation survives. Persistence of thermokarst features is further limited due to the nature of local sediment, namely scoria, being cohesionless, thereby limiting the retention of water that can be frozen. The disappearance of the former permanent snowline sub-aerially exposing much of the interior suggests interaction between frost and aeolian processes will provide potentially relevant avenues for future geomorphological research. Furthermore, interactions between frost and aeolian processes are extremely important for plant colonisation in an area that is almost entirely devoid of vegetation.Dissertation (MSc)--University of Pretoria, 2006.Geography, Geoinformatics and MeteorologyMScUnrestricte
Species differ in their responses to wind : the underexplored link between species fine-scale occurrences and variation in wind stress
Questions Species distribution models have traditionally relied heavily on temperature and precipitation, often ignoring other potentially important variables. However, recent advances have shown other climatic variables, including snow cover and solar radiation, may strongly improve predictions of species occurrence. Wind has long been known to have mechanical and physiological impacts on plants, but has not yet received adequate attention as a driver of species distributions. Location Marion Island, sub-Antarctic. Methods Using data from 1,440 plots in a chronically windy system, we test if wind stress (a combination of wind exposure and wind speed) improves species distribution models of vascular plant species, examining predictions for both species occurrence and cover. Results Wind stress was a significant predictor of the occurrence of 12 of the 16 species, even after accounting for seven other ecophysiologically important abiotic variables. Species showed differential responses to wind, but wind stress was among the four most important drivers for the majority of species when modelling occurrence patterns (10 of 16) and variation in cover (12 of 16). Further, wind stress was more important than all temperature and precipitation variables in predicting the occurrence of six species (and three species' cover). Conclusions Wind conditions were most influential for species that are characteristic of open, wet environments and for pteridophyte species, likely due to high wind speeds and exposure increasing the potential for moisture loss. This research highlights the value of incorporating wind metrics into species distribution models, particularly under changing wind patterns.Peer reviewe
An open access geospatial database for the sub-Antarctic Prince Edward Islands
Researchers of projects at the sub-Antarctic Prince Edward Islands are increasingly considering geospatial data as an essential component in answering scientific questions. A need exists for high-resolution geospatial data in both multi- and transdisciplinary research to better analyse fine-scale biotic–abiotic interactions of the Islands’ landscape and ecosystems within the context of climate change and the impacts of invasive species. However, much of the geospatial data that currently exist have limitations in spatial coverage and/or resolution, are outdated, or are not readily available. To address these issues, we present an online geospatial database for the Prince Edward Islands (both islands) produced from a high-resolution digital surface model and satellite imagery. This database contains vector files, raster data sets, and maps of topographical and hydrological parameters. It is freely available to download from Figshare – an open access data repository. We encourage the South African polar science community to make use of similar platforms for improved data sharing practices.
Significance:
A topographical and hydrological geospatial database – produced from a 1 m x 1 m digital surface model of the Prince Edward Islands – is provided.
These fine-scale geospatial data allow for a more comprehensive assessment of biotic–abiotic interactions at an island scale.
Also included are locality maps specifying place names and established long-term marine mammal monitoring beaches and coastal zones for improved cross-referencing.
The dataset is downloadable from an open access data repository and intended to promote open science and data sharing practices
Diagnostic criteria for pronival ramparts : site, morphological and sedimentological characteristics
Pronival ramparts are discrete debris accumulations found below steep rock faces at the foot of snowbeds or firn fields but they are often confused with moraines, protalus rock glaciers or rock-slope failure debris accumulations. This can be attributed to a poor understanding of the modes of rampart genesis, failure to recognise the significance of topography in their development and the use of inappropriate diagnostic criteria. Various characteristics have been suggested for identification of pronival ramparts but these are derived largely from relict features. Research on actively accumulating ramparts has shown that some of the suggested criteria are no longer useful. This paper reviews existing criteria and shows that, for diagnostic purposes, more emphasis should be placed on the attributes of actively accumulating features. A more robust set of criteria, derived from common characteristics of actively accumulating ramparts, are proposed that assists in discriminating relict and active pronival ramparts from other discrete bedrock cliff-foot debris accumulations.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1468-0459hb201
COVID-19 and the academe in South Africa: Not business as usual
The famous R.E.M. song laments ‘It’s the end of the world as we know it, I had some time alone, I feel fine…’. Many South Africans would agree that COVID-19 signals the end of the world (or business) as we know it, and through the lockdown we have certainly had some time alone. But contrary to the lyrics, all may not be fine, especially for South Africa’s scientific community. The novel coronavirus SARS-CoV-2 has impacted every economic and social sector1 across the globe, including higher education in South Africa. Every student and staff member at a higher education institution will have been affected in some way and to varying degrees; not one person will emerge from this unscathed. It is impossible to predict every short- and long-term impact of the COVID-19 pandemic, but we will experience the aftershocks for a long time to come. Here we discuss some of these impacts, ranging from undergraduate level to large research projects, and we offer suggestions on how to mitigate some of the damage.Geograph
The changing racial profile of academic staff at South African higher education institutions (HEIs), 2005–2013
South Africa has undergone transformation since the end of apartheid governance in 1994. Legislatively enforced, this transformation has permeated most sectors of society, including higher education. Questions remain, however, about the extent to which transformation has occurred in Higher Education Institutions (HEIs) in general, and across the academic staff body in HEIs in particular. In this study, we examine the transformation of academic staff profiles at HEIs throughout the country. Initially, we graph the racial profile of academics across multiple positions (junior lecturer to professor) from 2005 to 2013. We then use correlational analysis to identify which characteristics of universities in South Africa can be used to explain the racial inequities evident in South African HEIs. Our results indicate that world university ranking; percentage black African staff; percentage black African student body; and whether the university is 'historically disadvantaged', all influence the racial profile of the academic staff body to varying degrees. The size of the overall staff and study body does not appear to influence the racial profile of universities' staff component. We conclude that transformation of the academic staff body of HEIs in South Africa is indeed occurring, albeit slowly. Rather than seeing this as a negative, we argue that the pace of 'academic' transformation in the country needs to be interpreted within the framework of academic governance.http://www.tandfonline.com/loi/raer202018-03-30Geography, Geoinformatics and Meteorolog
Lake Itasca Greenway II
Report and posters completed by students enrolled in ARCH 3250: Community Design and Public Interest Architecture, taught by James Wheeler, and LA 3002: Informants of Creating Landscape Space, taught by Jessica Rossi-Mastracci and Joe Favour in spring 2018.This project was completed as part of the 2017-2018 Resilient Communities Project (rcp.umn.edu) partnership with the City of Ramsey. City staff identified a parcel of land for a proposed multi-use trail to connect Ramsey’s mixed-use, transit-oriented downtown area to nearby Lake Itasca. They partnered with students in ARCH 3250/LA 3002: Design Workshop/Informants of Creating Landscape Space, taught by James Wheeler, Joseph Favour and Jessica Rossi-Mastracci to create a conceptual design for the trail, including a proposed route and trail user amenities. The students’ final report is available.This project was supported by the Resilient Communities Project (RCP), a program at the University of Minnesota whose mission is to connect communities in Minnesota with U of MN faculty and students to advance community resilience through collaborative, course-based projects. RCP is a program of the Center for Urban and Regional Affairs (CURA). More information at http://www.rcp.umn.edu
Exposing wind stress as a driver of fine-scale variation in plant communities
The effects of temperature and precipitation, and the impacts of changes in these climatic conditions, on plant communities have been investigated extensively. The roles of other climatic factors are, however, comparatively poorly understood, despite potentially also strongly structuring community patterns. Wind, for example, is seldom considered when forecasting species responses to climate change, despite having direct physiological and mechanical impacts on plants. It is, therefore, important to understand the magnitude of potential impacts of changing wind conditions on plant communities, particularly given that wind patterns are shifting globally.
Here, we examine the relationship between wind stress (i.e. a combination of wind exposure and wind speed) and species richness, vegetation cover and community composition using fine-scale, field-collected data from 1,440 quadrats in a windy sub-Antarctic environment.
Wind stress was consistently a strong predictor of all three community characteristics, even after accounting for other potentially ecophysiologically important variables, including pH, potential direct incident solar radiation, winter and summer soil temperature, soil moisture, soil depth and rock cover. Plant species richness peaked at intermediate wind stress, and vegetation cover was highest in plots with the greatest wind stress. Community composition was also related to wind stress, and, after the influence of soil moisture and pH, had a similar strength of effect as winter soil temperature.
Synthesis. Wind conditions are, therefore, clearly related to plant community characteristics in this ecosystem that experiences chronic winds. Based on these findings, wind conditions require greater attention when examining environment–community relationships, and changing wind patterns should be explicitly considered in climate change impact predictions.National Research Foundation.http://www.wileyonlinelibrary.com/journal/jechj2022Plant Production and Soil Scienc
Exposing wind stress as a driver of fine-scale variation in plant communities
The effects of temperature and precipitation, and the impacts of changes in these climatic conditions, on plant communities have been investigated extensively. The roles of other climatic factors are, however, comparatively poorly understood, despite potentially also strongly structuring community patterns. Wind, for example, is seldom considered when forecasting species responses to climate change, despite having direct physiological and mechanical impacts on plants. It is, therefore, important to understand the magnitude of potential impacts of changing wind conditions on plant communities, particularly given that wind patterns are shifting globally.
Here, we examine the relationship between wind stress (i.e. a combination of wind exposure and wind speed) and species richness, vegetation cover and community composition using fine-scale, field-collected data from 1,440 quadrats in a windy sub-Antarctic environment.
Wind stress was consistently a strong predictor of all three community characteristics, even after accounting for other potentially ecophysiologically important variables, including pH, potential direct incident solar radiation, winter and summer soil temperature, soil moisture, soil depth and rock cover. Plant species richness peaked at intermediate wind stress, and vegetation cover was highest in plots with the greatest wind stress. Community composition was also related to wind stress, and, after the influence of soil moisture and pH, had a similar strength of effect as winter soil temperature.
Synthesis. Wind conditions are, therefore, clearly related to plant community characteristics in this ecosystem that experiences chronic winds. Based on these findings, wind conditions require greater attention when examining environment–community relationships, and changing wind patterns should be explicitly considered in climate change impact predictions.National Research Foundation.http://www.wileyonlinelibrary.com/journal/jechj2022Plant Production and Soil Scienc
An open access geospatial database for the sub-Antarctic Prince Edward Islands
Researchers of projects at the sub-Antarctic Prince Edward Islands are increasingly considering geospatial
data as an essential component in answering scientific questions. A need exists for high-resolution
geospatial data in both multi- and transdisciplinary research to better analyse fine-scale biotic–abiotic
interactions of the Islands’ landscape and ecosystems within the context of climate change and the impacts
of invasive species. However, much of the geospatial data that currently exist have limitations in spatial
coverage and/or resolution, are outdated, or are not readily available. To address these issues, we present
an online geospatial database for the Prince Edward Islands (both islands) produced from a high-resolution
digital surface model and satellite imagery. This database contains vector files, raster data sets, and maps
of topographical and hydrological parameters. It is freely available to download from Figshare – an open
access data repository. We encourage the South African polar science community to make use of similar
platforms for improved data sharing practices.
SIGNIFICANCE :
• A topographical and hydrological geospatial database – produced from a 1 m x 1 m digital surface
model of the Prince Edward Islands – is provided.
• These fine-scale geospatial data allow for a more comprehensive assessment of biotic–abiotic
interactions at an island scale.
• Also included are locality maps specifying place names and established long-term marine mammal
monitoring beaches and coastal zones for improved cross-referencing.
• The dataset is downloadable from an open access data repository and intended to promote open
science and data sharing practices.DATA AVAILABILITY: Dataset posted on 29.09.2022, 10:09 authored by Elizabeth Rudolph, David William Hedding, Nico De Bruyn and Werner Nel.
This database contains vector files, raster datasets, and maps of topographical and hydrological parameters of the sub-Antarctic Prince Edward Islands. Data production procedures are described in the associated paper (see references below) and the metadata are described in the "README" word document. The data is intended for scientific and/or educational use.
(https://figshare.com/articles/dataset/Prince_Edward_Islands_geospatial_database/19248626)South African National Research
Foundationhttp://www.sajs.co.zahj2022Mammal Research InstituteZoology and Entomolog
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