Pieter Olivier

Pieter Olivier
M.A.P Scientific Services

PhD Zoology

About

25
Publications
11,970
Reads
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544
Citations
Additional affiliations
January 2016 - present
University of Pretoria
Position
  • PostDoc Position

Publications

Publications (25)
Article
Full-text available
en State‐level conservation in South Africa is structured around distinct political entities (i.e. municipalities). This is problematic because an ecological approach that considers species distribution is required to delineate meaningful management units. To do so, vegetation types can be used as management units—however, it is uncertain whether v...
Article
Full-text available
Tropical landscapes are changing rapidly due to changes in land use and land management. Being able to predict and monitor land use change impacts on species for conservation or food security concerns requires the use of habitat quality metrics, that are consistent, can be mapped using above-ground sensor data and are relevant for species performan...
Preprint
Tropical landscapes are changing rapidly due to changes in land use and land management. Being able to predict and monitor land use change impacts on species for conservation or food security concerns requires the use of habitat quality metrics, that are consistent, can be mapped using above - ground sensor data and are relevant for species perform...
Preprint
Full-text available
Tropical landscapes are changing rapidly due to changes in land use and land management. Being able to predict and monitor land use change impacts on species for conservation or food security concerns requires the use of habitat quality metrics, that are consistent, can be mapped using above - ground sensor data and are relevant for species perform...
Article
Questions What drives canopy gap formation in regenerating coastal dune forest? Does canopy gap size‐frequency distribution differ between new‐ and old‐growth forests? Can canopy gaps divert regenerating trajectories?. Location Rehabilitating coastal dune forest in KwaZulu‐Natal, South Africa. Methods We mapped canopy gaps in regenerating dune fo...
Article
Full-text available
ContextEcological theory suggests that large habitat fragments should harbour more species than small fragments. However, this may depend on the surrounding matrix. Matrices in fragmented landscapes may either amplify or reduce area effects, which could influence predicted extinctions based on species-area relationships (SARs). Objective To determi...
Article
Full-text available
Background Canopy structure, defined by leaf area index (LAI), fractional vegetation cover (FCover) and fraction of absorbed photosynthetically active radiation (fAPAR), regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Me...
Article
Changes in structure and functioning of tree communities in response to forest fragmentation may alter tropical forest’s capacity to store carbon and regulate climate. However, evidence for indirect effects of forest fragmentation on above – and belowground carbon pools through changes in forest biodiversity is scarce. Here we focus on understandin...
Article
Full-text available
Forest edges influence more than half of the world's forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantif...
Article
Full-text available
The peninsula effect predicts that the number of species should decline from the base of a peninsula to the tip. However, evidence for the peninsula effect is ambiguous, as different analytical methods, study taxa, and variations in local habitat or regional climatic conditions influence conclusions on its presence. We address this uncertainty by u...
Data
This file contains the data from the article “Pattern or process? Evaluating the peninsula effect as a determinant of species richness in coastal dune forests” by Pieter I. Olivier, Victor Rolo, and Rudi J. van Aarde. (CSV)
Article
Functional diversity indicators are increasingly used to monitor forest function recovery because they connect biodiversity to ecosystem functions. However, identifying which functions deviate from a reference forest has not received much attention, despite its potential to inform restoration interventions. In this study, we used functional groups...
Article
South African coastal forests form part of two critically endangered eco-regions and harbor an extinction debt. Remaining fragments are small, isolated, and embedded within a range of human land-use types. In this study, we ask: how should we invest conservation resources if we want to restore this landscape and prevent predicted extinctions? To an...
Article
The planting or seeding of pioneer species to promote restoration apparently contributes little to the establishment of late-successional species, despite the common assumption that they facilitate forest regeneration. We evaluate the consequences of planting pioneers for coastal dune restoration by measuring plant traits (specific leaf area, wood...
Article
Questions Can trends derived from chronosequences (space) be compared with those derived from repeated surveys (time) to validate the use of space-for-time substitution? Can this approach provide insight into the dynamics of vegetation in rehabilitating forests? Location Rehabilitating coastal dune forest in KwaZulu-Natal, South Africa. Methods...
Article
Full-text available
We used a hierarchical fractal-based sampling design to test how sampling grain influences (1) beta diversity of and (2) inferences from the modelled contribution of niche- versus dispersal-based assembly processes in structuring tree and bird assemblages. Coastal forest fragments, South Africa. We surveyed 103 tree plots and 267 bird points within...
Article
Full-text available
AimPredicting extinctions before they are realized has proven difficult, yet is increasingly important for biodiversity conservation as habitat destruction continues unabated around the world. We evaluated whether habitat suitability models can be used in conjunction with species–area relationships (SAR) to detect apparent extinction debts as impli...
Article
We used dung surveys to estimate population size and extracted an age structure from boli diameters for the elephants living in the Maputo Elephant Reserve. Our estimate was based on published defecation rates, dung decay rates, distance-sampling techniques and 1,672 dung piles encountered on 204 line-transects. The reserve had at least 311 (95% CI...
Article
1The metapopulation metaphor is increasingly used to explain the spatial dynamics of animal populations. However, metapopulation structure is difficult to identify in long-lived species that are widely distributed in stochastic environments, where they can resist extinctions. The literature on mammals may not provide supporting evidence for classic...
Chapter
Full-text available
T HE PREVAILING INCREASE IN ELEPHANT numbers across areas of southern Africa raises concern for their impact on biological diversity. Several approaches to elephant management focus on limiting numbers to alleviate these consequences. However, landscape fragmentation, fences, water supple-mentation as well as the shape and size of some conservation...

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Projects

Projects (3)
Project
Analyse shifts in regimes of vegetation biophysical structure in tropical forest-savannah landscapes. Test for and quantify implications of regime shifts for ecosystem service provision (via links to ecosystem productivity, climate regulation, water flows, habitat provisioning for biodiversity linked to pollination and pest-control) at scales relevant for ecosystem management.
Project
Quantifying and projecting biodiversity responses to forest fragmentation at scales at which land use decisions are made. https://biofrag.wordpress.com/
Project
Globally, natural habitats are replaced by human land-use types. This results in the formation of novel landscapes where remaining natural habitats are typically surrounded by agricultural plantations, mines and human settlements. My research focuses on understanding how biodiversity respond to such land-use changes. This is important because if we are to meet conservation targets or regain ecosystem services, we have to evaluate patterns, processes, threats and opportunities that relate to biological diversity within such affected landscapes. Within this framework I have two main research themes. First, I study how birds and trees respond to human land-use changes in the coastal plains of northern KwaZulu-Natal and southern Mozambique. I specifically focus on understanding rarity, extinction risk and the role of matrix habitats that surround coastal forest fragments (e.g. sugarcane and agroforestry plantations versus natural grasslands and woodlands), in supporting regional diversity. I also investigate the drivers of community assembly and the potential role of ecological restoration to regain biodiversity losses and ecosystem services. My second research theme focus on understanding the factors that determine species diversity within South African protected areas. Similar to coastal forest fragments, protected areas are also islands surrounded by an ‘ocean’ of human land-use types. It follows that the same factors that influence species diversity within forest fragments may also influence species diversity within protected areas. I investigate this idea by studying if species diversity within protected areas are determined by the size of the area, its relative connectivity, shape and the habitats that surround these areas. I also investigate if South African protected areas harbor an extinction debt and if species diversity, and the factors that drive species diversity, are changing across time.