21 research outputs found
Ecosystem Interactions in a Heterogenous Landscape:Linking long-term patterns of landscape heterogeneity to changing ecosystem processes in the Kruger National Park, South Africa
Get PDFBiodiversity informatics: building a lifeboat for high functionality data to decision pipeline [Editorial]
Get PDFRainfall, geology and landscape position generate large-scale spatiotemporal fire pattern heterogeneity in an African savanna
Get PDFFire is considered a critical management tool in fire prone landscapes. Often studies
and policies relating to fire focus on why and how the fire regime should be managed,
often neglecting to subsequently evaluate management’s ability to achieve these
objectives over long temporal and large spatial scales. This study explores to what
extent the long-term spatio-temporal fire patterns recorded in the Kruger National
Park, South Africa has been influenced by management policies and to what extent it
was dictated by underlying variability in the abiotic template. This was done using a
spatially explicit fire-scar database from 1941 to 2006 across the 2 million hectare
Park. Fire extent (hectares burnt per annum) (i) is correlated with rainfall cycles (ii) exhibits no long-term trend and (iii) is largely non-responsive to prevailing fire
management policies. Rainfall, geology and distance from the closest perennial river
and the interactions between these variables influence large-scale fire pattern
heterogeneity: areas with higher rainfall, on basaltic substrates and far from rivers are
more fire prone and have less heterogeneous fire regimes than areas with lower
rainfall, on granitic substrates and closer to rivers. This study is the first to illustrate
that under a range of rainfall and geological conditions, perennial rivers influence
long-term, landscape-scale fire patterns well beyond the riparian zone (typically up to
15 km from the river). It was concluded that despite fire management policies which
historically aimed for largely homogeneous fire return regimes, spatially and
temporally heterogeneous patterns have emerged. This is primarily because of
differences in rainfall, geology and distance from perennial rivers. We postulate that
large-scale spatio-temporal fire pattern heterogeneity is implicit to heterogeneous
savannas, even under largely homogenizing fire policies. Management should be
informed by these patterns, embracing the natural heterogeneity-producing template.
We therefore suggest that management actions will be better directed when operating
at appropriate scales, nested within the broader implicit landscape patterns, and when
focusing on fire regime parameters over which they have more influence (e.g. fire
season).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1600-0587hb201
Drowning in data, thirsty for information and starved for understanding: A biodiversity information hub for cooperative environmental monitoring in South Africa
Get PDFThe world is firmly cemented in a notitian age (Latin: notitia, meaning data) – drowning in data, yet thirsty for information and the synthesis of knowledge into understanding. As concerns over biodiversity declines escalate, the volume, diversity and speed at which new environmental and ecological data are generated has increased exponentially. Data availability primes the research and discovery engine driving biodiversity conservation. South Africa (SA) is poised to become a world leader in biodiversity conservation. However, continent-wide resource limitations hamper the establishment of inclusive technologies and robust platforms and tools for biodiversity informatics. In this perspectives piece, we bring together the opinions of 37 co-authors from 20 different departments, across 10 SA universities, 7 national and provincial conservation research agencies, and various institutes and private conservation, research and management bodies, to develop a way forward for biodiversity informatics in SA. We propose the development of a SA Biodiversity Informatics Hub and describe the essential components necessary for its design, implementation and sustainability. We emphasise the importance of developing a culture of cooperation, collaboration and interoperability among custodians of biodiversity data to establish operational workflows for data synthesis. However, our biggest challenges are misgivings around data sharing and multidisciplinary collaboration
Drowning in data, thirsty for information and starved for understanding: A biodiversity information hub for cooperative environmental monitoring in South Africa
Get PDFThe world is firmly cemented in a notitian age (Latin: notitia, meaning data) – drowning in data, yet thirsty for information and the synthesis of knowledge into understanding. As concerns over biodiversity declines escalate, the volume, diversity and speed at which new environmental and ecological data are generated has increased exponentially. Data availability primes the research and discovery engine driving biodiversity conservation. South Africa (SA) is poised to become a world leader in biodiversity conservation. However, continent-wide resource limitations hamper the establishment of inclusive technologies and robust platforms and tools for biodiversity informatics. In this perspectives piece, we bring together the opinions of 37 co-authors from 20 different departments, across 10 SA universities, 7 national and provincial conservation research agencies, and various institutes and private conservation, research and management bodies, to develop a way forward for biodiversity informatics in SA. We propose the development of a SA Biodiversity Informatics Hub and describe the essential components necessary for its design, implementation and sustainability. We emphasise the importance of developing a culture of cooperation, collaboration and interoperability among custodians of biodiversity data to establish operational workflows for data synthesis. However, our biggest challenges are misgivings around data sharing and multidisciplinary collaboration
Common, low-frequency, rare, and ultra-rare coding variants contribute to COVID-19 severity
Get PDFThe combined impact of common and rare exonic variants in COVID-19 host genetics is currently insufficiently understood. Here, common and rare variants from whole-exome sequencing data of about 4000 SARS-CoV-2-positive individuals were used to define an interpretable machine-learning model for predicting COVID-19 severity. First, variants were converted into separate sets of Boolean features, depending on the absence or the presence of variants in each gene. An ensemble of LASSO logistic regression models was used to identify the most informative Boolean features with respect to the genetic bases of severity. The Boolean features selected by these logistic models were combined into an Integrated PolyGenic Score that offers a synthetic and interpretable index for describing the contribution of host genetics in COVID-19 severity, as demonstrated through testing in several independent cohorts. Selected features belong to ultra-rare, rare, low-frequency, and common variants, including those in linkage disequilibrium with known GWAS loci. Noteworthily, around one quarter of the selected genes are sex-specific. Pathway analysis of the selected genes associated with COVID-19 severity reflected the multi-organ nature of the disease. The proposed model might provide useful information for developing diagnostics and therapeutics, while also being able to guide bedside disease management. © 2021, The Author(s)
Quantifying spatiotemporal drivers of environmental heterogeneity in Kruger National Park, South Africa
Full text linkLinking long-term patterns of landscape heterogeneity to changing ecosystem processes in the Kruger National Park, South Africa
Get PDFThesis (PhDAgric)--Stellenbosch University, 2018.ENGLISH ABSTRACT: Biodiversity loss is a global threat to ecosystem function and human well-being. Environmental
heterogeneity is a recognised driver of biodiversity under a niche-based view of available
species habitats. As such, an increase in environmental heterogeneity is expected to promote
species coexistence, persistence and diversification. Loss of environmental heterogeneity is
therefore considered proximal evidence of biodiversity loss. At a landscape scale, this
heterogeneity is defined as the degree of difference between landscape elements and is often
described as landscape heterogeneity. Patterns of landscape heterogeneity are generated and
maintained by the physical landscape template or abiotic environment (e.g. topography,
geology and climate), upon which complex adaptive interactions between landscape pattern
(structure and composition) and ecological processes (function) occur. Landscape pattern can
therefore be described as the self-organising expression of landscape function which varies not
only across space but also through time. Accordingly, observable variations in landscape pattern
are conjectured to signify divergence in landscape function. This thesis explores this
relationship further within the Kruger National Park (Kruger): a large (~ 20,000 km2
), longestablished (proclaimed 1898) protected area in South Africa’s semi-arid savanna. Results
therefore describe landscape heterogeneity, in terms of the abiotic and biotic components
(environmental drivers) that generate and maintain landscape pattern in Kruger, to inform
strategic biodiversity planning. Chapter 1 introduces the reader to landscape heterogeneity and
its relevance to protected area management and biodiversity conservation. Chapter 2 begins by
isolating the effects of ‘stationary’ landscape properties on environmental heterogeneity
through their relationship with Landsat spectral variance. Results show this relationship is
sensitive to season and rainfall with the effects of dynamic ecosystem processes dominating
many areas. Thereafter, Chapters 3 and 4 examine in more detail the nature of selected dynamic drivers in Kruger, namely rainfall and elephants. Results demonstrate the existence of longterm spatiotemporal changes in both rainfall and elephant density and distribution patterns in
Kruger from 1985-2015. Together these results feed into chapter 5, where a Structural Equation
Model (SEM) is used to investigate the causal structure of landscape heterogeneity with stable
landscape properties, rainfall, herbivory and fire. Results are presented as path coefficients and
long-term driver dominance maps showing the magnitude and direction of the different cause
and effect relationships between heterogeneity, the physical landscape template, rainfall,
herbivory and fire return interval. Finally the nature of the environmental-heterogeneity theory
is operationalised in Chapter 6 using R, Shiny and Leaflet to provide an interactive web
interface for protected area managers to explore heterogeneity differences in context with park
specific research questions. Chapter 7 concludes the thesis with a brief synthesis of results in
context with current literature and highlights future research opportunities and possible directions.AFRIKAANSE OPSOMMING: Geen opsommingDoctora
Science support within the South African National Parks adaptive management framework
No full text‘Behind all good science is good science support.’ Implementing a successful strategic adaptive management (SAM) framework requires an effective science support structure. This structure must be effective in all areas of data management, starting with data collection and ending with the dissemination of knowledge, to facilitate timeous management decisions and associated actions. Accordingly, South African National Parks has embraced the use of various technologies to enable the effective implementation of a functional support structure. This paper described these technologies and discussed how they benefit the implementation of the SAM framework.
Conservation implications: The importance of functional support structures in science and conservation management is frequently undervalued in a system where emphasis is placed on scientific products. In order to promote research and facilitate analysis, sound data management practices are essential to integrating knowledge into an organisation’s institutional memory
Editorial: Biodiversity informatics: building a lifeboat for high functionality data to decision pipeline
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