THE POTENTIAL USE OF WETLAND PLANT SPECIES WITH IN A RENOSTERVELD SETTING FOR THE PHYTOREMEDIATION OF GLYPHOSATE AND FERTILISER by Dylan Michael Jacklin Thesis presented in fulfilment of the requirements for the degree of Master of Science in the Faculty of Science at Stellenbosch University Supervisor: Mr J de Waal Co-supervisor: Dr IC Brink December 2018 Department of Geography and Environmental studies Stellenbosch University https://scholar.sun.ac.za DECLARATION By submitting this thesis electronically, I declare that the entirety of the work contained therein is my own, original work, that I am the sole author thereof (save to the extent explicitly otherwise stated), that reproduction and publication thereof by Stellenbosch University will not infringe any third-party rights and that I have not previously in its entirety or in part submitted it for obtaining any qualification. DM Jacklin Date Copyright © 2018 Stellenbosch University All rights reserved i Stellenbosch University https://scholar.sun.ac.za DEDICATION The author wishes to dedicate this thesis to his mother. ii Stellenbosch University https://scholar.sun.ac.za ABSTRACT In South Africa, fertiliser and herbicide pollutants resulting from various agricultural practices lead to a degradation of surface freshwater and groundwater quality. Nitrogen and phosphorous, and glyphosate derived from agricultural fertiliser and herbicide applications, respectively, significantly contribute to watercourse toxicity. Adjacent to many of the surface freshwater systems are some of the South Africa’s most productive agricultural fields, which convert the surrounding natural ecosystems in favour of the crops produced. As a result, the degradation of natural vegetation and deterioration of freshwater quality is observed. The critically endangered status of some Renosterveld vegetation types is the product of agricultural expansion, nutrient loading through fertilisation and the spraying of herbicides. The characteristics of phytoremediation provide an attractive alternative for the pollutant biofiltration of freshwater aquatic ecosystems. A buffer of Renosterveld vegetation along river corridors may be a solution for agricultural pollutant remediation prior to entering the watercourses. As a result of its successful uptake and metabolism capabilities of fertilisers and herbicides, inexpensiveness, aesthetic advantages and long-term use, it has become a remediation technology of choice in developing countries. The utilisation of wetland plants occurring within Renosterveld vegetation for pollutant extraction from agricultural practices will increase river corridor biodiversity, creating indigenous refuges, and facilitating habitat connectivity. Considering this, the study aims to delineate the potential use of wetland plant species indigenous to Renosterveld for the effective removal of agricultural pollutants. The evaluation of plant species’ pollutant removal efficiency in comparison to unvegetated soil will substantiate its use in vegetative buffer strips. The potential use of indigenous species as an alternative to invasive alien plant (IAP) species, currently considered successful phytoremediators, will aid in conserving the Renosterveld ecoregion. An experimental phytoremediation system was designed and constructed under laboratory conditions to investigate the pollutant removal potential of indigenous vegetation. Five pollutant parameters, namely ammonia, nitrate, soluble reactive phosphorous and two glyphosate concentrations (0.7 and 225 mg/L), were selected to reflect environmental stresses on 14 indigenous wetland species. The high but non-lethal glyphosate dosage strength was selected by means of a dual species dilution series experiment, where two plant species were subjected to ten different glyphosate concentrations. The dosage strength was selected at a concentration where plants did not display signs of mortality. Effluent analyses indicated the exceptional removal efficiencies of the indigenous wetland species across both fertiliser and herbicide pollutants, with the two most beneficial species identified as the species selected for this test aquic Phragmites australis and Cyperus textilis. The unvegetated soil control further exhibited efficient pollutant removal. However, indigenous vegetation consistently displayed greater pollutant removal than the unvegetated soil control. When compared to the IAP and Palmiet (Prionium serratum) multi-plant iii Stellenbosch University https://scholar.sun.ac.za community assemblage, the indigenous species indicated similar pollutant removal efficiencies, justifying the use of indigenous plant species over the alien invasive equivalent. Phytoremediation presented significant potential for the utilisation of non-invasive wetland plant species in agricultural pollutant remediation, ameliorating freshwater aquatic ecosystems, and aiding the conservation of the already fragmented landscape. iv Stellenbosch University https://scholar.sun.ac.za OPSOMMING In Suid-Afrika lei kunsmis- en onkruiddoder-besoedelingstowwe wat aanwesig is tydens verskeie landbou aktiwiteite tot die afname van die oppervlak varswater asook ondergrondse water. Stikstof, fosfaat en glifosaat afkomstig vanuit landboukunsmis en onkruiddoders dra aansienlik by tot die toksisiteit van waterlope. Sommige van Suid-Afrika se mees produktiewe landbouindustriee is aangresend tot oppervlak-varswatersisteme, en vereis die omskakeling van die omliggende natuurlike ekosisteme om die groei van aangeplante gewasse te bevorder. Die agteruitgang van plantegroei en natuurlike habitatte asook die varswater- kwaliteit word dus waargeneem. Renosterveld-plantegroei is sodoende op ‘n kritiese bedreigde vlak weens verskeie bevrugtingvoedingstowwe, asook die bespuiting van onkruiddoders. Die eienskappe van fytoremediëring bied 'n aantreklike alternatief vir die biofiltrasie van besoedeling met betrekking tot varswater-akwatiese ekosisteme. 'n Buffer van Renosterveld-plantegroei kan 'n effektiewe oplossing bied vir die herstelling van landboubesoedelende middels voordat dit waterlope binnedring. Die suksesvolle opname en metabolieringsvermoëns met betrekking tot kunsmis en onkruiddoders, tesame met die koste- effektiwiteit, estetiese voordele en langtermyn toepaslikheid, het dit alreeds die vooraanstaande remediëringstegnologie in verkeie ontwikkelende lande gemaak. Dit sal ook inheemse toevlugsoorde skep wat habitatverbindings fasiliteer. In die lig hiervan is die studie daarop gemik om die potensiële gebruik van vleiland-plantspesies te definieer vir die effektiewe verwydering van Landbou-besoedelstowwe. Die evaluering van inheemse vleiland plantspesies se verwyderingsdoeltreffendheid in vergelyking met onbegroeide grond sal die gebruik daarvan in vegetatiewe bufferstroke staaf. Die potensiële gebruik van inheemse- spesies as 'n alternatief vir indringerplantspesies, wat tans as suksesvolle fytoremediatore beskou word, sal help om die area te bewaar. 'n Eksperimentele fytoremediëringsisteem is ontwerp en gebou onder laboratoriumtoestande om die verontreinigingspotensiaal van inheemse plantegroei te ondersoek. Vyf besoedelende parameters, naamlik ammoniak, nitraat, oplosbare reaktiewe fosfor en twee glifosaat konsentrasies (0,7 en 225 mg / L), is geidentifiseer en gekies om omgewingstressors op 14 inheemse vleiland-spesies te weerspieël. Die hoë, maar nie-dodelike glifosaat-dosis sterkte is gekies deur middel van 'n eksperiment wat ‘n dubbele spesies verdunning reeks bevat, waar twee plantspesies aan tien verskillende glifosaat konsentrasies blootgestel was. Die dosis sterkte is die konsentrasie waar plante nie tekens van mortaliteit vertoon het nie. Verskeie uitvloeisel-ontledings dui op die uitsonderlike doeltreffendheid van die verwydering van inheemse vleiland-plantspesies oor beide kunsmis- en onkruiddoder-besoedelingsstowwe met die twee mees voordelige spesies geïdentifiseer as Cyperus textilis en Phragmites australis, onderskeidelik. Die grondbeheer het verder doeltreffende kontaminante verwyder. Vleiland-plantegroei het egter meer kontaminante as die onbedekte grondbeheer verwyder. In vergelyking met die indringerspesies insluitend Palmiet, het inheemse-plantegroei soortgelyke besoedelingsverwydering-doeltreffendheid aangedui, wat die gebruik van inheemse v Stellenbosch University https://scholar.sun.ac.za plantspesies oor die uitheemse indringende plus Palmiet ekwivalent regverdig. Fytoremediasie het aansienlike potensiaal getoon vir die gebruik van die nie-indringende vleiland-spesies in die voorkoming van landbou-besoedelstowwe asook die verbetering van varswater-akwatiese ekosisteme, wat in geheel tot die bewaring van die reeds gefragmenteerde landskap sou bydra. vi Stellenbosch University https://scholar.sun.ac.za THE RUFFORD FOUNDATION The Rufford Foundation is a UK registered charity that funds nature conservation projects across the developing world. The author gratefully acknowledges the Rufford Foundation for their generous financial assistance to this research project [23296-1], granting stability for the duration of the project. vii Stellenbosch University https://scholar.sun.ac.za ACKNOWLEDGEMENTS I would like to thank the following people and organisations for their assistance and contribution to the success of this study: My supervisor Mr J de Waal (Geography and Environmental Studies, Stellenbosch University) for his guidance and constant support for the duration of the project. My co-supervisor Dr IC Brink (Water and Environmental Engineering, Stellenbosch