Quantifying the effectiveness of private land conservation areas in preventing losses of natural land cover and biodiversity intactness across South Africa

Thesis (MScConsEcol)--Stellenbosch University, 2019.

ENGLISH ABSTRACT: Global biodiversity conservation targets cannot be achieved by relying on state-owned protected areas (PAs) alone. Private land conservation areas (PLCAs) are one potential complementary conservation strategy. However, despite their increasing extent and recognition, little is known about their effectiveness in conserving biodiversity, or how different environmental and social-ecological factors influence their effectiveness. In South Africa, a long history of conservation on PLCAs and the diverse PLCA models provide an interesting case study to address this knowledge gap. The effectiveness of PLCAs across South Africa, and factors influencing their effectiveness, were thus quantified using losses in natural land cover (NLC) and the biodiversity intactness index (BII) as proxies. NLC was based on 1990 and 2013 national land cover maps, while BII represented a measure of the percentage of major taxa that can persist in an area given different land use scenarios. Points within PLCAs were matched with unprotected control points to test the prediction that if PLCAs offer effective protection, losses in NLC and BII would be significantly lower within their boundaries in comparison to unprotected controls exposed to similar conditions. NLC and BII losses were then compared across different types of PLCAs, with the hypothesis that legally protected PLCAs would be more effective than the informal ones. Of particular interest was also how different factors influenced the effectiveness of PLCAs in preventing losses of NLC and BII. In that regard accessibility (distance to road, distance to town, elevation and slope), rainfall, age and size of PLCAs were considered as explanatory variables. There were significant differences in losses in NLC and BII between PLCAs and matched unprotected areas. PLCAs lost 3% NLC and 2% BII between 1990 and 2013, while unprotected areas lost 6% NLC and 4% BII. These findings indicate the relative effectiveness of PLCAs, and provide insight into the implications of NLC loss on biodiversity intactness, thus advancing standard approaches for quantifying PA effectiveness. There were also significant differences in losses of NLC and BII between different types of PLCAs. However, contrary to the hypothesis, effectiveness did not depend on legal protection, as informal PLCAs were relatively more effective than some of the formally protected ones. NLC and BII losses were likely to occur at points within PLCAs that were closer to towns, further from roads, with low elevation, gentle slopes, within small and old PLCAs, and with low rainfall. This supports research on state-owned PAs, in which highly accessible areas were shown to be less effective due to higher human pressure. This study provides evidence that PLCAs are relatively effective, which is highly relevant given current discussions around their inclusion towards biodiversity targets. The study also highlights how different factors influence the effectiveness of PLCAs, which has important implications on where best to establish future PLCAs and how different management strategies and policies can be better placed to facilitate biodiversity conservation within PLCAs. The study contributes to the growing body of knowledge about PLCAs as a complementary biodiversity conservation strategy worth considering, which future studies can build upon.

AFRIKAANSE OPSOMMING: Wereldwye pogings of biodiversiteit te beskerm kan nie ekslusief op beskermde gebiede (BG) wat deur die staat besit word staat maak nie. Privaat land bewaring gebiede (PLBGe) is een moontlike, komplimentêre bewaring strategie. Ten spyte van die immer-groeiende omvang en erkenning van die gebiede wereldwyd, is die mate tot wat PLBGe effektief is meestal steeds onbekend. Kennis met betrekking tot die invloed van kontekstuele sosiaal-ekologiese faktore op genoemde effektiewiteit is soortgelyk beperk. Danksy Suid-Afrika se lang geskiedenis met PLBG bewaring, sowel as sy diversiteit van PLBG instrumente, bied dié land ‘n interessante gevallestudie wat hierdie kennisgaping kan aanspreek. Hierdie studie het dus die effektiwiteit van PLBGe regoor Suid-Afria, sowel as die faktore wat daardie effektiwiteit beïnvloed, gewantifiseer, Tot daardie doeleinde het ek verliesse in natuurlike gronddekking (NG), sowel as die biodiversiteit intaktheid indeks (BII), as proksies gebruik. Die NG was gebaseer op die nasionale landbedekking kaart van 1990 en 2013 en die BII verteenwoordig die persentasie van ‘n meerderheid taksa wat in ‘n area kan voortbestaan onder verkillende landgebruike. Ek het punte binne PLBGe gepaar met kontroleer punte buite PLBGe om die voorspelling te toets dat, indien PLBG effetiewe bekserming bied, verliesse in NG and BII aansienlik laer sou wees binne hulle grense in vergelyking met onbeskermde kontroleer punte met soortgelyke omgewings. Ek het daarna NG en BII verliesse vergelyk tussen verskillende tipe PLBGe, met die verwagting dat PLBGe wat wettig beskerm word meer effektief sou wees as meer informele PLBGe. Ek was veral geïnteresseer in hoe verskillende kontekstuele faktore die effektiwitiet van PLBGe beinvloed, soos gemeet deur die vermoë van ‘n PLBG om verliese van NG en BII te voorkom. Moontlike verklarende faktore het toeganklikheid (gemeet deur afstand-tot-by-naaste-pad en –dorp, sowel as elevasie en helling), reënval, ouderdom en gebied grote ingesluit. Daar was ‘n aansienlike verskil in NG en BII verliesse tussen PLBGe en gepaarde onbeskermde punte. Terwyl PLBGe 3 % NG en 2 % BII verloor het tussen 1990 en 2013, het onbeskermde punte 6 % NG en 4 % BII verloor. My bevindings dui op die relatiewe effektiewiteit van PLBGe, bied insig oor die implikasies van NG verlies vir biodiversiteit intaktheid, en bevorder die tegniese kwantifisering van BG effektiewiteit. Daar was ook aansienlike verskille tussen NG- en BII verliese tussen verskillende kategoriee PLBGe. Teen verwagtinge was effektiwiteit egter nie afhanklik van wettige beskerming nie, aangesien informele PLBGe relatief meer effektief as sekere kategorieë formele gebiede was. NG en BII verliesse is meer gereëld gevind op punte wat nader aan dorpe en verder van paaie was, punte met laer elevasie, sagter hellings, en laer reënval, en punte binne ouer en kleiner beskermde gebiede. Hierdie resultate is ondersteunend van navorsing op staat-beheerde BG, wat wys dat meer toeganklike areas minder effektief is as gevolg van hoër mensdruk. Hierdie studie verskaf bewys dat PLBGe relatief effektief is, ‘n bevinding wat uiters relevant is vir kontemporêre besprekings rondom hulle insluiting in formele biodiversiteit teikens. Hierdie studie beklemtoon ook hoe verskeie faktore die effektiwiteit van PLBGe beïnvloed, wat belangrike implikasies het vir die optimale vestiging van toekomstige BGs, sowel as die mees gepaste besturing strategieë en beleide vir biodiversiteit bewaring in verskillende PLBGe. Die studie lewer bydrae tot die toenemede kennis van PLBGe as ‘n komlimentêre bewarings strategie.

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