Optimising the use of visual and radar observations for the mitigation of wind energy related impacts on Cape Vultures (Gyps coprotheres) in the Eastern Cape Province

Becker, Frowin Klaus (2016-03)

Thesis (MSc)--Stellenbosch University, 2016.

Thesis

ENGLISH ABSTRACT: Being one of the leading global renewable energy investors over the last few years, South Africa’s energy sector is undergoing a rapid transformation. This transformation has been driven by the Renewable Energy Independent Power Producers Procurement Programme (REIPPPP) – a competitive bidding process, which has already concluded four bidding windows since 2011. Wind energy has comprised the bulk of the approved projects, thus far. Its accelerated development, however, poses a threat to the country’s airborne wildlife. Birds have been amongst the avifauna, most affected by wind energy facilities (WEF), both directly and indirectly. These impacts include collision-induced mortalities, habitat loss, costly avoidance behaviour, and barrier effects, which have been well documented in Europe and the United States. In response to such impending risks, South Africa’s environmental sector has drawn up a set of guidelines for baseline studies, pre-construction, and post-construction monitoring of birds. Two of the recommended monitoring techniques are direct or visual observations, and radar observation, which formed the foundation of this study. Due to its morphology, phenology and flight behaviour, the Cape Vulture (Gyps coprotheres) is considered as particularly vulnerable to WEFs, and has recently been deemed ‘endangered’, both locally and globally. Considering the species’ somewhat fragile status, using it as the primary subject, only added more significance to the study. The aims were to (1) assess the accuracy of visual observations, and (2) investigate activity patterns amongst Cape Vultures in the Eastern Cape Province, using a marine surveillance radar (EchoTrack Inc.). The proposed Umtathi Emonyeni WEF near Komga (-32.577°, 27.888°) in the Eastern Cape Province, served as the study site. Here, three radar placement sites were established. Vantage point (VP) and radar observations were conducted simultaneously from October 2014 to June 2015. A total of five replicates were completed in that time, one consisting of 12 days. Four days were spent at each placement site. Visually assessed targets were plotted using a cross-platform Geographical Information System (GIS), which allowed for the recording of coordinates. Parameters captured by the radar included latitudinal and longitudinal coordinates, flight height, reflectivity (size), and the airspeed of each target. Using customised EchoTrack software, visual and radar tracks were matched with a certain degree of confidence, depending on temporal, spatial and directional margins. A total of 66.4% of all visual observations were matched with corresponding radar tracks. The mean difference in time and distance, between those tracks, was 108.8s and 262.7m, respectively. Those margins were highly significant between Cape Vultures and other priority species. The dataset also indicated a significant positive relationship between both degree of inaccuracy and the distance of the target from the radar, as well as the degree of inaccuracy and the target’s height. Using the visually verified Cape Vulture radar tracks, target airspeed and size were used to distinguish the remaining unverified dataset from other bird tracks. Movement frequency (observations/hour), climbing rate (m/s), and flight height all exhibited similar patterns, with peaks being reached during the middle of the day. Trends in movement frequencies were valid for both visual and radar observations. Results presented here highlight the inconsistencies that govern visual monitoring. They also demonstrate the broad practical uses of avian radar systems. Implementing a comprehensive pre-construction monitoring regime is of great value to both the developers and bird conservationists. Collecting high-quality data vastly improves the reliability of the mitigation strategies that are put in place, and ensures that impacts are efficiently minimised. This also benefits developers as minimal impacts decrease the probability of costly compensations. While radar’s application is limited to bird movements, and still requires augmentation through visual observations, the quality of data produced adds significant value to both research and management decision-making. Obtaining data of such high quality is even more valuable for the conservation of endangered species, like the Cape Vulture.

AFRIKAANSE OPSOMMING: Suid-Afrika is die afgelope paar jaar een van die wêreld se voorste beleggers in hernubare energie en is tans besig om ‘n vinnige transformasie te ondergaan. Hieride transformasie word aangedryf deur die Renewable Energy Independent Power Producers Procurement Programme (REIPP) – ‘n kompeterende bie proses, wat alreeds vier bedingings vensters afgesluit het vanaf 2011. Windkrag maak so ver die grootste komponent van die goedgekeurde projekte op. Die versnelde ontwikkeling van windkrag hou egter bedreigings in vir die land se vlieënde wild. Voëls word die ergste van alle vlieënde diere geaffekteer deur wind energie fasiliteite (WEF), beide direk en indirek. Hierdie impakte is goed gedokumenteer in Europa en die Vereenigde State van Amerika en sluit in sterftes veroorsaak deur botsings, habitat verlies, kostelike vermydingsgedrag, en versperrings-effekte. Suid-Afrika se omgewingssektor het gereageer op hierdie bedreigings deur riglyne op te stel vir basislyn studies en pre- en post-konstruksie monitering van voëls. Twee moniteringstegnieke word aanbeveel: direkte of visuele waarnemings, of radar waarnemings. Die twee tegnieke vorm die basis van hierdie projek. As gevolg van die morfologie, fenologie en vlieg gedrag word die Kransaasvoël (Gyps coprotheres) beskou as besonder kwesbaar vir WEFe, en is onlangs plaaslik en internasionaal gelys as ‘bedreig’. Die gebruik van die bedreigde Kransaasvoël as hoof onderwerp in hierdie navorsing dra dus by tot die belangrikheid en beduidenheid van hierdie projek. Die doelstellings van hierdie studie was om (1) die akuraatheid van visuele waarneemings te evalueer, en (2) aktiwiteitspatrone van Kransaasvoëls te ondersoek in die Oos-Kaap met gebruik van ‘n mariene waarneming radar (EchoTrack Inc.). Die studie area was die voorgestelde Umtathi Emonyeni WEF naby Komga (-32.577o, 27.888o) in die Oos-Kaap. Die radar is op drie plasingspunte opgestel. Visuele uitkykpunt (VP) en radar observasies is gelyktydig uitgevoer vanaf Oktober 2014 tot Junie 2015. ‘n Totaal van vyf replikas is tydens die periode voltooi, en elke replika het 12 dae geduur. Vier dae is spandeer by elke radar plasingspunt. Visuele geassesseerde teikens is geplot met behulp van ‘n kruis-platform Georafiese Informasie Sisteem (GIS), wat toegelaat het vir die opname van koordinate. Die radar het lengte- en breedtegrade, vlug hoogte, weerkaatsing (grootte) en die lugspoed van elke teiken opgeneem. EchoTrack sagteware is gebruik omvisuele en radar spore te vergelyk met ‘n redelike mate van vertroue, afhangende van temporale, ruimtelike en rigting marges. ‘n Totaal van 66.4% van alle visuele waarneemings het gepas by ooreenstemmende radar spore. Die algemene verskil in tyd en afstand tussen daardie spore was 108.8s en 262.7m onderskeidelik. Die marges was hoogs beduidend tussen Kransaasvoëls en ander prioriteit spesies. Die data stel het ook aangedui dat ‘n beduidende positiewe verhouding bestaan tussen die graad van onakkuraatheid en die afstand van die teiken vanaf die radar, asook die graad van onakuraatheid en die hoogte van die teiken. Deur die gebruik van die geverifieerde Kransaasvoëls radar spore kon teiken lugspoed en grootte gebruik word om die ongeverifieerde datastel van ander voëls se radar spore te identifiseer. Bewegings-frekwensie (waarnemings/uur), klim koers (m/s), en vlug hoogte het soortgelyke patrone gevolg, en hoogtepunte is tydens die middle van die dag bereik. Tendense in bewegings-frekwensies was geldig vir beide visuele en radar waarnemings. Die resultate wat hier aangebied word beklemtoon die teenstrydighede van visuele waarnemings. Verder toon die resultate dat pre-konstruksie monitering van kardinale belang is vir beide die ontwikkelaars en die bewaringsekoloë. Die versameling van hoë gehalte data verbeter die vertroubaarheid van die versagting strategië wat in plek gestel word, en verseker dat impakte op voëls doeltreffend verminder word. Dit bevoordeel ook ontwikkelaars, aangesien ‘n afname in impakte die waarskynlikheid van kostelike vergoeding verminder. Terwyl die radar se toewending beperk is tot slegs die voëls se bewegings, en gelyktydige visuele waarnemings toegevoeg moet word, dra die hoë gehalte van die data wat verkry word by tot navorsing en besluitneming. Verkryging van sulke hoë gehalte data is selfs meer belangrik vir die bewaring van bedreigde spesies, soos die Kransaasvoël.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/98716
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