Towards adaptive management of high-altitude grasslands: Ingula as a case study

Maphisa, David Hlosi

Towards adaptive management of high-altitude grasslands: Ingula as a case study

Doctoral Thesis

2015

Publisher

University of Cape Town

Department

Department of Statistical Sciences

Faculty

Faculty of Science

Abstract

Eastern high - altitude grasslands of South Africa are centres for endemism and harbour fauna and flora of regional and international conservation concern. This area also provides important ecological services such as provision of water to communities downstream. Sweet and sour veld support beef livestock farming during summer months. The aesthetic beauty of the region makes the area a prime tourist destination too. More recently the area is becoming a target of other agricultural projects such man - made forests. Other new developments that need to be mitigated against are development of renewable energy projects such as pumped water schemes to generate electricity or wind farms. Additional habitat is lost when these projects are connected to the national grid. In this thesis, I use bird data and vegetation data to compare, contrast and suggest management tools to manage this area. I present data that I collected at Ingula Pumped Storage Scheme spanning five years from the beginning of the construction of the scheme to near its completion in 2012 as a case study to manage similar habitats. Chapter 1 presents a brief overview of ecological importance of this area and the history behind the construction of pumped storage scheme at Ingula. A literature review in Chapter 2 investigates management tools to manage these grasslands for avian diversity. Fire and grazing is a key management tool cited to make habitat suitable for birds. While few studies from this type of grassland exist, studies from outside South Africa suggest that fire and grazing supplement each other as management tool to make habitat suitable for species with contrasting ecological requirements. A mosaic of grass heights and cover across the landscape translates to species habitat suitability. Chapter 3 explores species richness through years, seasons and impact of grass height and cover on bird species richness. Species richness was highest in summer suggesting that management should make habitat for species suitable in summer when most priority species are likely to use the habitat. The main disadvantage of using bird species richness is that fieldworkers must know their species well. Secondly, use of species richness must be treated with caution because this method does not account for species detectability in time and in space. In Chapter 4 I use hierarchical distance sampling models which take into account both the detection and the biological process. To demonstrate this I used common grassland bird species which can easily be identified during monitoring. The downside of this approach is that because these species are common and therefore occur almost everywhere, they may not easily respond to lack of habitat heterogeneity. The technical disadvantage of using this method is to accurately allocate species to within distance bands, making this method challenging for fieldworkers. Chapter 5 presents random plot occupancy which records only detection - nondetection of birds during repeated plot surveys. This method accounts for observational and biological processes too and in addition implements rigorous statistical inferences to predict how birds respond to habitat variable s as influenced by management decision on fire and grazing. Finally, adverse weather conditions may hamper surveying all plots in some years. Through occupancy modelling it is possible to predict species occupancy on plots that were not surveyed during some years and finally this method has been improved to include rare species. This is my preferred method to monitor management effect on habitat suitability for birds at Ingula. Adaptive management, a pillar of which is adaptive monitoring is a new paradigm shift in conservation. In Chapter 6, I capture interactions between burning and grazing and effects on grass height and cover to predict habitat suitability for birds including large threatened Ingula birds using a simulation models. This model sets a stage for implementing adaptive management through experimental plots to capture a set of management uncertainties regarding the use of fire and grazing as management tools. Chapter 7 summarizes the thesis and acknowledges that Ingula consists of other equally important habitat and ecosystem such as cool moist mountain forest and matrix of grassland wetland that equally need to be conserved.

Description

Includes bibliographical references

Keywords

Statistics

Ecology and Conservation

Reference:

Collections

PhD / Doctoral

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