BINDURA UNIVERSITY OF SCIENCE EDUCATION
FACULTY OF ENVIRONMENTAL SCIENCE DEPARTMENT
RICHNESS AND DIVERSISTY OF WOODY AND HERBACEOUS SPECIES AT ASTRA CAMPUS, BINDURA UNIVERSITY OF SCIENCE EDUCATION
KUGEDERA TINASHE B1231342
A DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS OF THE BACHELOR OF ENVIRONMENTAL SCIENCE NATURAL RESOURCES MANAGEMENT
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DEDICATION
I dedicate this research to my family, God bless you all for your support and sympathy.
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ACKNOWLEDGMENTS
I am grateful to everyone who contributed towards the success of this study. I am grateful to my research supervisor Mr. G. Chikorowondo for the commitment shown during the whole research process it was not easy but your sympathy encouraged me may God bless you. I would like to express my appreciation to my best friend Paul Kganyago for helping me during my data collection. I would also like to acknowledge the efforts and support of Mr Kundhlande for helping me on species identification. Thank you all.
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ABSTRACT
Biodiversity assessment and monitoring is critical to effective ecosystem management. It helps to monitor changes which might affect the ecosystem processes and function. Therefore the study aimed to assess the richness and diversity of woody and herbaceous vegetation around Astra campus. A stratified random design was used with less, moderate and heavily disturbed areas being the strata. A Kruskal Wallis test was used to test level of significance amongst the threes strata for abundance, richness and diversity. There was no significance difference in density (P>0.05, H=0.989) across strata. Diversity was also similar (P>0.05, H=2.34) across the strata. However, least disturbed areas recorded the highest diversity (Shannon H=2.01). Biodiversity monitoring must be a continuous operation in order to monitor disturbances which might hinder ecosystem function especially invasion and extinction of species. The study recommends for continuous monitoring of biodiversity in and around the campus. The authorities must improve on landscape management and use environmentally sound methods.
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DEDICATION ...... i ACKNOWLEDGMENTS ...... iii LIST OF FIGURES PAGE ...... vii LIST OF ACRONYMS AND ABBREVIATION ...... viii CHAPTER ONE: INTRODUCTION ...... 1 1.1 Background to the study ...... 1 1.2 Problem Statement ...... 1 1.3 Justification ...... 2 1.4 Aim ...... 2 1.5 Objective ...... 2 1.6 Research Hypothesis ...... 2 CHAPTER TWO: LITERATURE REVIEW ...... 3 2.1Conservation of biodiversity ...... 3 2.1What is a biodiversity inventory? ...... 4 2.2The value of biodiversity inventory in monitoring ...... 4 2.3 What is biodiversity ...... 6 2.4The importance of biodiversity ...... 6 2.5Threats associated with biodiversity ...... 7 2.6 Impacts of invasive species ...... 9 CHAPTER THREE: METHODOLOGY ...... 11 3.1 Study area...... 11 Table 3.1 Showing materials and their use ...... 12 3.2 Methods...... 12 3.3.1Research design ...... 12 3.3.2Sampling design ...... 12 3.3.3Data collection method ...... 12 3.4 Data analysis ...... 13 CHAPTER FOUR: RESULTS ...... 14 4.1 Checklist of herbaceous species...... 14 CHAPTER FIVE: DISCUSSION ...... 19 5.1 Species abundance ...... 19 5.2 Species richness ...... 19 5.3 Species diversity ...... 20 5.4 Invasive species ...... 20 6.1 Recommendations ...... 21 6.2 Conclusion ...... 21 REFERENCES ...... 22
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LIST OF FIGURES PAGE
Fig 3.1 : Map of Astra Campus...... 12 Fig 3.2 : Quadrat format...... 14 Fig 3.2: Quadrat along a transect line...... 14 Fig 4.1 : Mean abundance of herbaceous species...... 17 Fig 4.2 : Total abundance of herbaceous species...... 18 Fig 4.3: Total abundance of woody species...... 21
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LIST OF ACRONYMS AND ABBREVIATION
FAO: Food and Agriculture Organisation UNEP: United Nations Environment Programme UNESCO: United Nations Educational Scientific and Cultural Organisation
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CHAPTER ONE: INTRODUCTION
1.1 Background to the study
The inventorying and monitoring of biodiversity represents a major theme and high priority of the programme of ecosystem function (UNESCO, 1992). The concern is to estimate problems related to the species number and their distribution around the world. The problems associated with biodiversity loss are undetailed inventories around the world. Also, ignoring data lead to underestimation of biodiversity loss thus to prevent that, inventories have came into practice thus biodiversity data of a given ecosystem can be compiled (Cutko, 2009). More so, to fully promote conservation of biodiversity, periodic checklists or inventory should be conducted (Stork , 1997). Inventory or biodiversity data can be used as biodiversity monitoring tool. Inventories provide current state of ecosystem thus change can be noticed (UNESCO, 1992). Moreover inventories helps in identifying areas which need maintenance within an ecosystem. Inventories also helps in mapping and describing significant species in an ecosystem thereby giving light on how they can be protected to limit chances of extinction. Inventories have a scientific importance thus they assess ecosystem processes like production, decline, regeneration and response to disturbance (Hill, 2005). Species richness and diversity has been used as biodiversity monitoring tool in some conservation areas for instance parks and protected areas of Canada have been conducting biological inventory work in order to repair gaps within biological diversity (Barnes, 1989). Despite biodiversity loss in Zimbabwean ecosystems a little has been done to promote periodic inventory operations. Anthropogenic activities cause ecosystem change especially in most developing countries and therefore it is important to make periodic inventories to make planning easier (Wilson and Peter, 1988).
1.2 Problem Statement
Astra campus might be a victim of ecological degradation as evidenced in proliferation of invasive alien species, plant monocultures and land degradation. This is mainly driven by anthropogenic disturbances including trampling, mowing and landscape management. Native species might be being replaced by problematic invasive alien species and their richness and diversity might be on the decline. 1
1.3 Justification
Biodiversity monitoring and assessment is critical for determining the small changes in ecosystem processes and functions before catastrophic and irreversible problems happen (Stock, 1997). Biodiversity data will be used to monitor disturbances which might happen from time to time and formulation of environmentally sound management strategies. It serves as a baseline study for future studies in biodiversity assessment and monitoring. Monitoring also helps in mapping and describing significant species in an ecosystem thereby giving light on how they can be protected to limit chances of extinction. This study has a scientific importance thus it will help in assessing ecosystem processes like production, decline, regeneration and response to disturbance. 1.4 Aim
To assess the richness and diversity of woody and herbaceous vegetation at Astra campus
1.5 Objective
1. To establish a species checklist of woody and herbaceous species in three selected habitat strata (less, moderate and high disturbed areas). 2. To determine species richness, abundance and diversity of woody and herbaceous species in three selected habitat strata. (less, moderate and high disturbed areas).
1.6 Research Hypothesis
Species richness, diversity and abundance is expected to be high with decreasing disturbance.
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CHAPTER TWO: LITERATURE REVIEW
2.1Conservation of biodiversity
The real problem the world face is the failure to conserve biodiversity. While everyone agrees that conserving natural resources is a good idea, there is no consensus on how to go about it (Hill, 2005). Every group, from governmental agencies to agro businesses to concerned individuals has their own idea of what conservation of biodiversity means, and what measures should be taken to achieve it (Gaston and Spicer 2004). Further, each group has its own agenda to pursue, and may regard some factors of conservation of biodiversity as threats to those agendas. Part of the problem is that conservation of biodiversity is quite costly.
Developing countries have just begun to develop the technologies necessary to preserve biodiversity hotspots, but trying to restore an area to its original state is not only costly, it is often impossible (Sala et al, 2000). Further, no one solution fits all hotspots. However with so many groups and interests, and the high costs, it is clear that the conservation of biodiversity is a complicated matter. Yet, if it is not resolved during our lifetimes, the problems accumulate and our descendants will be even more complicated and harder to resolve (Groombridge, 1996). Biodiversity as genetic species and as intact ecosystems can be best preserved in-situ by setting aside an adequate representation of wilderness as protected areas. These include national parks and wildlife sanctuaries which receive protection from governmental and international agencies (Jenkins, 1985).
However, there are situations in which an endangered species is so close to extinction that unless alternate methods are instituted, the species may be rapidly driven to extinction. This strategy is known as ex-situ conservation (Sala et al , 2000). Botanical gardens and zoological parks are set up for multiplying species of plants and animals in artificially managed conditions. Most of the world’s bio rich nations are developing countries and the countries capable of exploiting biodiversity are the developed nations. In order to have access to these resources the developed countries have vested interest in making biodiversity a common property resource to be shared by all nations (Groombridge and Jenkins 2002).
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International agreements such as World Heritage Convention attempts to protect and support many hotspots of biodiversity in different parts of the world. Another treaty known as the Convention in the Trade of Endangered Species (CITES) intends to reduce the utilization of endangered plants and animals by controlling trade in their products (Cutko, 2009). However having conservation in mind, inventories are being used as biodiversity monitoring tools. 2.1What is a biodiversity inventory?
An inventory is a list of biological entities from a particular site or area, these entities may be genes, individuals, populations and habitats (Stork, 1997). It is also defined as a stock take of vegetation composition, structure and condition at one point in time without any intended measurement (Hill et al, 2005). Inventory is a biodiversity monitoring tool which must be included in achieving conservation of biodiversity. Inventories provide accurate data on species richness, composition as well as the spatial and temporal structuring of communities (UNESCO 1992).
2.2The value of biodiversity inventory in monitoring
Inventory and monitoring are undertaken at a wide range of scale basing with intended objectives to be achieved. General inventory and monitoring may contribute to fundamental ecological knowledge of ecosystems patterns and processes. Examples include the effects of site factors such as altitude and drainage on vegetation composition; succession pathways following disturbance like fire (Helman, 1983). More over having biodiversity data knowledge may be critical for interpreting the outcomes of management focused studies for instance effects of invasive species (Wiser et al , 1988). Inventories shades light on management focused studies that may also contribute to fundamental knowledge. At the local level, most biodiversity monitoring is management focused, aimed at assessing the need for, or effectiveness of, some kind of intervention for instance areas which need attention at most (Sala et al , 2000). Inventory is a monitoring tool thus after biodiversity data compiled knowledge on vegetation composition, structure, and condition can be used as indicators of wider ecosystem condition. For example, an aerial canopy survey determines that un controlled possum populations are causing excessive canopy dieback; the effectiveness of subsequent possum control is assessed by monitoring canopy dieback, canopy cover, and seedling regeneration on permanent sample sites before and after (Mueller and Ellenberg1974).
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Globally nature supports lot of species but however conservation have not been fully addressed in terms of inventory, thus there are virtually no place where on the ground Inventories of biodiversity are considered complete when they do not have information about scarce taxa (Ponomarenko and Alvo, 2005). This is particularly true in remote or inaccessible areas, such as large parts of Latin America and Canada. The variation in inventory data is represented by the appropriately named “university hot spot” phenomenon, whereby high concentrations of rare species are often found within a short drive of universities with botany or zoology departments (Cutko, 2009).
Increasingly, land managers are becoming proactive about biodiversity inventories. Inventories have been recognized that they are cost effective to document hot spots in advance since it incorporates them appropriately into planning than waiting disasters to occur first. In this regard, having biodiversity information starting at local level its critical since financial exposure is minimised due to limited risk which might affect ecosystems (McPeek and Miller, 1996) More so inventory promotes sustainable development thus some species considered extinct can be identified giving room for their conservation to limit extinction .Biodiversity inventories basing with less known species may actually result in the down listing of species previously mentioned as rare thus such data can be shared among interested parties like local heritage or conservation data centre (Ponomarenko and Alvo, 2005). More over biodiversity inventory provides a tool for evaluating ecosystem health so as to maximise economic and health benefits and this is termed green infrastructure (Stohlgren et al ,1996).
Inventories serve as the basis of forest management plan thus information about species distribution can be of greater concern and if there are necessary vacant gaps other species can be grown (Hill et al , 2005). In addition monitoring promotes preservation of natural resources, thus areas of ecological value can be identified and local people encouraged to work towards conservation for instance like what happened in the town of Stratham. The town carried an inventory to map and describe significant natural resources, identify areas of high ecological at local, regional and state level as well as giving proper recommendations for the protection of resources (UNEP, 2006). Biodiversity inventory and monitoring provides fundamental and essential biological information used by many basic scientific disciplines for example systematic, population biology, behaviour, ecology and other fields of comparative biology and many applied sciences 5 for instance biotechnology, forestry, conservation and environmental science (Heywood, 1995). Biodiversity inventory promotes identification of species, results of identification and monitoring are important for developing conservation strategies, plans and sustainable use of resources as a measure of supporting article 8,9 and 10 of the Convention on Biological Diversity (Holdgate, 1996).
Biodiversity monitoring is important in identification of economic valuable wild species what is termed bio prospecting. According to the world conservation monitoring centre through inventories ecosystem processes can be understood so that ecological services essential for human survival can be maintained, and anthropogenic impacts reduced. More so by inventories, ecosystem aesthetic benefits can be identified promoting ecotourism activities and conservation. 2.3 What is biodiversity
Biodiversity includes variety of life and it can be studied at many levels depending with one’s area of interest that is can be studied both on small scale or broader scales. However identifying and understanding the relationships between all the lives on Earth are some of the greatest challenges in science in which inventory try to address but it needs team work of experts. Biodiversity as a scientific term also includes genetic and ecological biodiversity . Genetic Biodiversity is the variation in genes that exists within a species for example some citrus species grow to a certain height and some can not grow to that height. Ecological Biodiversity is the diversity of ecosystems, Biodiversity is a concept designed to demonstrate the wealth of an area in terms of its natural diversity. The term is a contraction of ‘biological diversity’ and is generally considered to be an amalgam of three separate aspects of natural diversity that is genetic, species and habitat biodiversity (UNEP, 1992).
2.4The importance of biodiversity
Biodiversity is extremely important to people and the health of ecosystems. Biodiversity allows human beings to live healthy lives in the sense of getting proper oxygen from trees. More so it provides food and materials and it contributes to the economy. Most medical discoveries to cure diseases and lengthen life spans were made because of research into plant and animal biology and genetics for example Vernonia amygdalina used to cure stomach pains, anti cancer drugs like taxo from taxus trees and hycamtin from camptotheca (FAO, 2001).Without biodiversity we would be a homogeneous population, with each of us having
6 the same vulnerabilities. This would mean that in case of an epidemic, we would all be killed since there would be no biologic differences that would enable some of us to survive and adapt (Jenkins, 1985). Much of our modern medicine is based on combinations of biologically diverse substances isolated from various plants which therefore, labelled medicinal. Even before the rise of modern medicine, ayurveda and unani systems of medicine used various plants to achieve various results. Without those plants, and the great variety of insects that pollinate and cross pollinate them, humans would be much more vulnerable to disease (Born et al , 2005). Every time a species goes extinct or genetic diversity is lost, it becomes difficult to get another research concerned with vaccines found in different species. Biodiversity is an important part in ecology; it makes life affordable on earth. The ecological function of biodiversity includes cleaning water and absorbing chemicals which wetlands do, providing oxygen for proper breathing of human beings. Biodiversity allows for ecosystems to develop defence mechanisms to threats like extreme fires and other anthropogenic (UNESCO, 1992).
Biodiversity play a significance role in the regulation and control of infectious diseases, so biodiversity loss and ecosystem change can increase the risk of emergence or spread of infectious diseases in animal, plants, and humans. Reduction in anthropogenic impacts to ecosystems can reduce outbreak of diseases like skin cancer due to reduction of ultra violet radiation (UNEP, 2006).
More over biodiversity provide important natural buffers against natural disasters such as floods and drought. Normally rural people pose threats to ecosystems yet there are the one again benefit from this ecosystem at most (UNESCO, 1992).Sustainable management of biodiversity can helping to provide essential resources for promoting healthy and rebuilding livelihood an post crisis situation (FAO, 2001).
2.5Threats associated with biodiversity
Biodiversity is a fragile thing, susceptible to all sorts of threats despite it supports all life on earth, it is constantly facing threats and damage that is almost impossible for our multiple ecosystems to recover (Sala et al , 2000).Threats to biodiversity come from many sources, most human but some natural. Largest among the threats to biodiversity looms human greed, Historically, humans have always taken what they needed from the earth itself and from its plant and animal species, with no regard as to whether the resources being consumed were finite or not (Purvis and Hector, 2000). It has only been since the middle of the 1980s, as species
7 started becoming extinct at a record rate, that threats to biodiversity became recognized as a major concern (Stein, 2000).
Extinction has become the most threat of biodiversity thereby making goal of sustainable development unachievable. Historically the planet’s most species that ever existed evolved and then gradually went extinct (May, 1988). Species go extinct because of natural shifts in the environment that take place over long periods of time, such as ice ages. However today, species are driving to extinction at an accelerated and dangerous rate this is so because of non natural environmental changes caused by human activities. Some of the activities have direct effects on species and ecosystems, such as habitat loss, over exploitation of resources as well as spread of invasive species which can cause sudden change to ecosystems (Stein, 2000). Activities like degradation can lead to climate change in the long run.
Biodiversity threats have put a serious strain on the diversity of species on Earth, globally about one third of all known species are threatened with extinction and if people do not stop the threats to biodiversity, nations could be facing another mass extinction with dire consequences to the environment and human health as well as livelihood. Due to threats associated with ecosystems periodic inventory ventures as a monitoring tool for ecosystems disturbances to be fully minimised (May, 1988). Overexploitation a classic tragedy of the commons, people tend to use natural resources with exploitation in mind for example in activities like poaching and cutting down of tress (Chapin et al, 1996). More over invasive species is another threat to ecosystems they out compete and drive indigenous, and especially endemic, species to extinction (UNEP, 1992).A main reason for the degradation of the natural environment is population pressure, but there are other cultural factors that have compounded the problem and most threats are anthropogenic (Selin, 2003). Population growth the continuous increase in human population exerts population pressure on many ecological and evolutionary processes and functions thus cutting down of trees can be highly experienced thereby affecting ecosystem function as a whole (Purvis and Hector,2006). More over due to population growth poverty and hunger increases thus too much pressure which exceeds carrying capacity of ecosystem became threats to ecosystem function since activities like deforestation, poaching will experienced (Sebastian, 2006).In other words population growth leads to overconsumption of resources.
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More over misperception is also a threat ,that is most government are not willing to enjoy long benefits of ecosystems thus they might fail to fund programmes which promote biodiversity rather they only fund departments like medical of which they should be bio centric economic policies (Barnes, 1989). Humans are omnivorous, without biodiversity there would be virtually no variety in diets one reason to ask “why is biodiversity important?” is because biodiversity provides a literal treasure trove of food. Further, not all the nutrients we need are in any particular food, so without a diverse base of foods to make combinations from our general health would suffer (Sala et al , 2000). Biodiversity sustains the bodies we live in, and affects the lives we lead, and the societies we form (Gaston and Spicer, 2004). 2.6 Impacts of invasive species
Invasive species are organisms (plant, animal, and bacterium), that is not native and has a negative effect on environment. Invasive species also threaten ecosystem function. The impacts of invasive species in ecosystem services have attracted world wide attention, despite the overwhelming evidence of these impacts and a growing appreciation for ecosystem services, however, researchers and policy makers rarely directly address the connection between invasions and ecosystem services. Various attempts have been made to address the ecosystem processes that are affected by invasive species (Callaway and Ridenour, 2004).
Invasive species influence change to ecosystems and changes in species and community structure can affect ecosystem services both directly and indirectly (Born et al , 2005). Direct effects include the decline in abundance of economically valuable species in particular those used for food, forage, fiber, fuel, or medicine (Helman, 1983). Aesthetic values are commonly lost with the arrival of nuisance species such as invasive vines or aquatic floating plants. Moreover invasive species that disrupt mutualisms pose risks particularly for pollination and natural pest control services (Chapin et al , 1996). Indirect effects include a potential decrease in ecosystem resistance and resilience to change, due to the hypothesized link between stability and changes in biodiversity (Heywood,1995). More so interactions of invasive species may lead to increased vulnerability to further invasion, and potential degradation of ecosystem services increases (Simberloff and Von Holle, 1999).
Invasive species can introduce unknown pathogens that normally spreads diseases which ecosystem can fail to resist thereby the diseases can be transferred from ecosystems to human populations. Again invasive species are competitive so other species can fail to compete for
9 nutrients, water and this can lead to biodiversity loss (Collaway and Ridenour, 2004). Invasive species can also alter the physical habitat .Both plant and animal invaders are capable of outcompeting natives and taking over habitat, and certain invaders additionally make the habitat less suitable for other species. Invasive plants may decrease the suitability of soil for other species by secreting salts for example Tamarisk (Vivrette and Muller 1977). Invasive species can acidify the soil, or by release novel chemical compounds, as in allelopathy (Callaway and Ridenour, 2004). However inventory of ecosystem helps in evaluating ecosystem that are at risk and invasive species dominant as well as their impacts. Predicting which invasive species will have the greatest impact on ecosystem services would have both economic and societal benefits, and allow introduction of preventive and management strategies (Constantino, 2002).
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CHAPTER THREE: METHODOLOGY
3.1 Study area
The study was carried out at Astra Campus of Bindura Unversity of Science Education, Mashonaland central province. Annual temperatures on average range from 24 0c to 32 0c and average rainfall on balance is 847 mm per year. The area is prone to anthropogenic disturbances and fire experienced almost every year and it is affecting growth of vegetation. Invasive species are increasing due to the fact that different people dispose different seeds which are sometimes invasive. Anthropogenic activities like trampling; mowing and landscape management suppresses growth of most herbaceous species.
Fig 3.1 map of Astra campus
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Table 3.1 Showing materials and their use
Material Use Tape measure Measuring k th individual to place the quadrat Quadrat For sample plots. Transect line Marking of systematic points and dividing plots
3.2 Methods
The area to collect herbaceous data, it was grouped in to three categories basing with disturbances that is less disturbed (back of the computer laboratories up to the apiary), moderately disturbed (between lecture rooms) and highly disturbed (car park area).
3.3.1Research design
A stratified random design was used to select the sampling zones. The highly and moderate disturbed areas were homogeneous thus quadrats were thrown systematically in a zig zag way. As for less disturbed which was heterogeneous because of buildings a transect line was first laid and a 1m by 1m quadrat was used to collect data along the laid transect. Quadrat system was used they produce results considered sufficient mostly in sampling plants (Winkworth and Goodall, 1962). 3.3.2Sampling design
Systematic random sampling was used to collect data. Systematic random sampling involves random start and then proceeds with the selection of every k th element like on this research the 10 th element and quadrat system was used.
3.3.3Data collection method
All woody species which were found in the two categorised strata were enumerated. Herbaceous species data was collected from each quadrat placed in every strata (less, moderate and highly disturbed) and all herbaceous species inside each quadrat were recorded. The species identification was done using the Zimbabwean botanical checklist (Mullin, 2003) and
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those not identified were stamped and later identified using the book, Grasses of Southern Africa (Frits, 2012) and the identification of species was done to species level.
Fig 3.2 showing quadrats in a zig zag
Fig 3.3quadrates along the transect line placed after 10m
3.4 Data analysis
Species diversity and richness was measured for all species that were identified using biodiversity calculators. This was done to compare the variations between plant species across the study area. The formula for Shannon Weiner used is given below. Shannon Weiner (H) = ∑S Pi In P i Where: S is the total number of species (richness) in the community; :P i is the proportion of S made up to the ith species.
The data obtained for species abundance was subjected to one way analysis of variance (ONEWAY ANOVA) per each categorised area using SPSS Version 21. The difference between means was tested at a 5 % level of significance. Graphs of abundance were drawn from SPSS at 5% level of significance.
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CHAPTER FOUR: RESULTS
4.1 Checklist of herbaceous species
The checklist below shows that species of the family Poacese and Asteracease was high at less disturbed sites followed by moderately disturbed and disturbed respectively. Apiaceae was only found only on moderately disturbed and disturbed sites. Gramineae was found at all three sites, less disturbed, moderately disturbed and disturbed. Species of family Zygophyllaceae was only found at less disturbed sites .
Table 4.1 Herbaceous checklist
Order family genus/species less moderately disturbed Total disturbed disturbed Poales Poaceae Cynodon nlemfuensis + 7 Cynodon dactylon + + + 54 Panicum deustum + 3 Sporobolus pyramidalis + + + 18 Urochloa brachyuran + 2 Setaria incrassate + + 7 Setaria sphaceleta var. Sphacelata + 13 Hyparrhenia filipendula + 25 Brachiaria xantholeuca + + 3 Trugus berteronianus + + + 40 Bathriochloa radicans + 6 Asterales Asteraceae Conyza sumatrensis + + + 18 Bidens pilosa + + + 43 Sonchus arvensis + + 23 Sonchus oleraceus + + + 8 Ageratum conzoides + + + 29 Chrysanthemum leucanthemum + 92 Malpighiales Euphorbiaceae Euphorbia esula + + + 43 Euphorbia heterophylla + + + 31 Euphorbia hirta + + + 15 Cyperales Gramineae Sporobolus consimilis + + + 28 Zygophyllales Zygophyllaceae Tribulus terrestris + 2 Lamiales verbenaceae Verbena bonarensis + 13 Apiales Apiaceae Apium leptophyllum + + 15
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Table 4.2 Woody species checklist The woody species checklist shows that Moringa oleifera has the highest abundance followed by Carica papaya , Acacia polyacantha , Citrus sinensis , Delonix regia respectively. Species of order Fabales, Celastrales, Malvales and Caryophyllales had the lowest total abundance.
Genus/species Order family Total abundance Moringa olifeira Brassicales Moringaceae 95 Carica papaya caricaceae 19 Acacia polyacantha Fabales Fabaceae 17 Citrus sinensis Sapindales Rutaceae 14 Delonix regia Fabales Fabacaea 12 Melia ezedarach Sapindales Meliaceae 9 Ziziphus mauritiana Rosales Rhamnaceae 8 Mangifera indica Sapindales Anacardiaceae 7 Bauhinia thonningii Fabales Fabaceae 6 Eucalyptus grandis Myrtales Myrtaceae 5 Euphorbia pulcherima Malpighiales Euphorbiaceae 4 Psidium guajava Myrtales myrtaceae 4 Vernonia amygadalina Asterales Asteraceae 4 Spathodea campanulata Lamiales Bignoniacaea 4 Duranta erectus Verbenaceae 4 Hyphaena benguellensis Arecales Arecaceae 3 Trichilia ametica Sapindales Meliaceae 3 Persia Americana Laurales Lauraceae 3 Red rose Rosales Rosaceae 2 Jacaranda mimosifolia Lamiales Bignoniacaea 2 Red jatropher Malpighiales Euphorbiaceae 2 leucaena leucocephala Fabales Fabacaea 2 Prunus persica Rosales Rosaceae 1 Morus nigra Moraceae 1 white rose Rosaceae 1 Albizia amara Fabales Fabaceae 1 Pterocarpus rotundifolia Fabaceae 1 Lonchocarpus capassa Fabaceae 1 Maytenus heterophila Celastrales Celastraceae 1 Hibiscus Malvales Malvaceae 1 Nelia orianda Caryophyllales Aizoaceae 1
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Table 4.3 herbaceous species diversity, richness and abundance Mean ± SE (Shanon – diversity H) The table below shows that diversity, richness and abundance was high at moderately disturbed sites followed by less disturbed and disturbed respectively.
VARIABLE LESS MODERATE DISTURBED F P DISTURBED value value DIVERSITY 1.922±.0151 1.926±.0197 1.840±.0106 4.45 0.048
RICHNESS 0.115±.0020 0.118±.0036 0.107±.0010 2.43 0.039
13.11±3.004 13.83±4.943 6.57±2.444 1.87 0.001 ABUNDANCE
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The grass species shows that Chrysanthemum leucanthemum had the highest abundance at Moderately disturbed site followed by Trichodesma zeylanicum at less disturded sites. Less species abundance was found at disturbed sites except Trugus berteronians.
Fig 4.2 Species abundance for herbaceous species with site
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The fig below shows that site A has the highest abundance followed by site B with Moringa oleifera , Carica papaya and Acacia polyacantha with the highest abundance at site A. Melia ezedarach has a high abundance at site B.
Fig4.3 species abundance of woody species with site
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CHAPTER FIVE: DISCUSSION
5.1 Species abundance
Abundance less disturbed area was more of associated with non native species for example Trichodesma zeylanicum and this is so because these non native species are perennial plants and they cope to environment so quickly as compared to some grass species like Panicum deustum . It might be as a result of competition over available resources which result in the reduction in species abundance to weaker species. However species like Hyparrhenia filipendula , Setaria incrassate and Bidens pilosa looks as if they managed to overcome competition or these species do not like too much soil moisture to survive. Also, there are species which only appeared in one area for instance Brachiaria xantholeuc a found in moderate disturbed area Trichodesma zeylanicum found in less disturbed area, Urochloa brachyura , this alone explains difference in species variations as well as different conditions they favour the most for example Urochloa brachyura most favours disturbed areas and in other words it developed defensive mechanisms to survive in such conditions .More over there are species which were dominant per each area , this might as a result of higher competitive ability or rapid reproduction due to favourable soil condition for example chrysanthemum leucanthemum in moderate area looks as if the chemical and physical soil attributes of the area were favourably suitable for its growth that’s why it was dominant with higher abundance. More over there are some species which appeared in all areas less, moderate and disturbed areas for example Cynodon dactylon , this explains that some species besides being perennial they have improved defensive mechanisms to survive under disturbances for instance , competition for nutrients. Species abundance and evenness basically affected by completion, spatial heterogeneity as well as time (Hill, 1993).
5.2 Species richness
Species evenness was less at less and disturbed than moderate disturbed area, this is so because species can not be too close due to different disturbance since the area is used as car park some species due to low of tolerance limit they fail to survive under massive disturbance thus only few species can survive for instance Tragus berteronianus and Sporobolus pyramidalis. Competition or species interaction affects evenness thus the more the competition the less the evenness but however some species can develop mechanisms as defence criteria and those species fail to fight competition die or go extinct (Hill, 2005).
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5.3 Species diversity
More so species diversity of less disturbed and moderately disturbed area is almost the same, the reason might be based on soils that is soils might be the same to be favoured by different species can be as a result of disturbances incurred are not that much different so species are likely to be affected almost the same in both areas. However the there are some species which can only found in moderate area but not in less disturbed area like Chrysanthemum leucanthemum and Claytonia perfoliata . This can be as a result of soil moisture because these species normally grows were there is moisture therefore, less disturbed area is not wet as moderate disturbed .More so species diversity in disturbed area is lower because of the area is prone to disturbance almost daily so only species which can fight disturbances of such magnitude are only the ones found for instance Trugus berteronianus grows well in disturbed areas . The point is the area is bare, rainfall is causing erosion, cars and human tracks also pose disturbances so the area can not support number of different species since some species can not survive under such disturbances. Species diversity refers to the number of different species represented at a given area and diversity is mainly affected by time thus might be low in summer since most species favours rain season, completion affect diversity thus it will be survival of the fittest so those species failure to overcome completion can run extinct or relocate some where (Purvis and Hector, 2000). . 5.4 Invasive species
Moreover looking at the checklist it shows invasive species like Verbena bonarensis have invaded the place and the main reason being invasive species mostly favours wetland areas thus if they are not monitored change can be experienced thus some species can fail to survive under invasive species competition. Concerning trees and shrubs, Moringa oleifera was dominant because it was used by an academic as research. The area has limited indigenous species it is only dominated by exotics which normally regenerate fast. Indigenous species available include the rain tree Lonchocarpu scapassa and Albizia amara. In other words the area is dominated by exotics since there are the once being planted and it looks as if the indigenous species available were not grown by the university rather there were already there when the university established. Exotics grow rapidly and regenerate at fast rate for example Melia ezedarach disperse seeds mostly during rain season
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6.1 Recommendations
• Further research is needed to be done every season before annual species die • Proper monitoring of invasive species to limit chances of change and competition for resources • Growing of indigenous trees should be promoted.
6.2 Conclusion
Biodiversity monitoring and assessment is very crucial thus through biodiversity data, it gives opportunity for proper management strategies which promote conservation. The research might not cover the big area but the ideologies applied qualify to be used at local, national and global level.
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