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Ecology and Conservation of Bird Assemblages in Native and Afforested Environments in the Northern Campos Grasslands of UruguayMartínez Lanfranco, Juan Andrés 08 December 2017 (has links)
Commercial forestry has expanded across the Rio de la Plata Grasslands (RPG) of South America in recent decades. I conducted a resource-use based study on bird communities during the 2013-2014 austral breeding season in northern Uruguay. I assessed relationships between habitat types and bird abundance as a function of vegetation structure. To compare avian responses to treatments, I included native environments, pine and eucalyptus plantations of different ages and thinning regimes. I detected differences in species richness and composition and species-specific responses in abundance along structural gradients sampled. Although poorer in species than native habitat types, tree plantations were extensively used by birds. Birds associated with plantations were primarily habitat generalists and forest dependent species, with low incidence of grassland specialists. Results of my study provide baseline information for stand-level management and future landscape design of timber plantations to benefit conservation of bird communities in afforested landscapes in the RPG.
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How flower visitation of remnant grassland patches is affected by commercial timber plantations and an invasive alien species (Rubus cuneifolius)Hansen, Simone 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Our planet is in the midst of a biodiversity crisis, with factors such as land transformation,
climate change, anthropomorphic disturbance and invasive species acting together to threaten
biodiversity. In South Africa, with minimal natural wood resources, commercial forestry is one
of the most abundant forms of landscape transformation. However, a third of the land inside
many plantations has been set aside for conservation as unplanted remnant grassland patches
(RGPs). These areas are subjected to an additional negative impact by invasive alien species,
namely Rubus cuneifolius (American bramble), a weed that is particularly problematic in and
around forestry plantations in South Africa. The grassland biome of South Africa is extremely
diverse and is of vital importance for the ecosystem services it supplies. Despite this, the
grassland biome is under threat as this is where much of South Africa’s forestry plantations are
located. Driven by anthropomorphic disturbance, pollinators are in decline. Landscape
transformation of natural areas for forestry plantations is likely to affect plant-pollinator
interactions which will affect ecosystems and biodiversity. However, it is not known to what
extent these ecosystems are affected. It is thought that the impact depends on the complexity
of the ecosystem in question, and analyses at the network-level provide insights into the
robustness of ecosystems in the face of biodiversity loss. Thus, this study evaluates the effect
of natural habitat fragmentation and invasion of the alien species, R. cuneifolius, on flower
visitation networks of South African grasslands.
The study was conducted in the KwaZulu-Natal Midlands within a commercial timber
plantation and a neighbouring protected area (PA). Flower-visitor observations were carried
out in uninvaded protected areas and RGPs and in protected areas and RGPs invaded by R.
cuneifolius. I found that RGPs within commercial forestry plantations successfully decrease
the negative effects of land transformation on the grasslands of the KwaZulu-Natal Midlands,
and flower visitation network patterns are largely maintained in these habitat fragments.
However, within RGPs, invasion by R. cuneifolius affected the composition and the interaction
network structure of flower-visitor and plant communities.
The fact that there are unplanted areas within commercial forestry plantations is positive for
biodiversity conservation in South Africa. Research has indicated that these areas successfully
aid in the conservation of biodiversity and ecosystem functioning. Due to the positive influence
that RGPs have on conservation in fragmented and transformed landscapes, it is critical that
these unplanted areas are retained. However, the effects of bramble invasion are more intense
within RGPs than within protected areas, and therefore, it must be a priority to keep these areas
undisturbed. R. cuneifolius has been found to have devastating effects on ecosystem function
and network structure. It is also a category 1 invasive plant within South Africa, and its removal
is required by law. Therefore, the removal of bramble must be a management priority. / AFRIKAANSE OPSOMMING: Ons planeet is in die middel van 'n biodiversiteit krisis, met faktore soos grond transformasie,
klimaatsverandering, antropomorfiese versteuring en indringerspesies wat gesamentlik werk
om biodiversiteit te bedreig. Suid-Afrika, besit minimale houtbronne. Daarom is kommersiële
bosbou een van die mees algemene vorme van landskap transformasie. Tog is 'n derde van die
land binne baie plantasies opsy gesit vir bewaring as oorblywende grasveld kolle (OGKs).
Hierdie gebiede word ongelukkig blootgestel aan die bykomende negatiewe impak van die
uitheemse spesies, Rubus cuneifolius (Amerikaanse steekdoring), wat veral problematies is in
en rondom bosbouplantasies. Die grasveldbioom van Suid-Afrika is baie divers en is van
kardinale belang vir die ekosisteem dienste wat dit lewer. Ten spyte hiervan, word die
grasveldbioom bedreig waar dit op dieselfde areas as die meerderheid van Suid-Afrika se
bosbouplantasies geleë is. Antropomorfiese versteuring lui daartoe dat bestuiwergetalle daal.
Landskap transformasie vir bosbou plantasies raak dus plant-bestuiwer interaksies, wat
ekosisteme en biodiversiteit beïnvloed. Dit is nie bekend tot watter mate hierdie ekosisteme
geraak word nie. Daar word vermoed dat die impak af hang van die kompleksiteit van die
ekosisteem. Ontledings van ekosisteme op netwerk vlak kan insigte bied oor die robuustheid
van hierdie ekosisteme in die aangesig van biodiversiteitverlies. Dus, die studie evalueer die
effek van fragmentasie van natuurlike habitatte en inval van die indringer spesie, R. cuneifolius,
op blom-besoekings netwerke van Suid-Afrikaanse grasvelde.
Hierdie studie is uitgevoer in die KwaZulu-Natal Midlands binne 'n kommersiële hout plantasie
en 'n naburige beskermde gebied (BG). Blom-besoeker waarnemings was in BGs en OGKs
sonder R. cuneifolius, en in BGs en OGKs met R. cuneifolius uitgevoer. Ek het gevind dat
OGKs binne kommersiële bosbouplantasies suksesvol is om die negatiewe uitwerking van land
transformasie te verminder, en blom-besoeking netwerk patrone grootliks gehandhaaf word in
hierdie habitat fragmente. Egter, binne OGKs, het R. cuneifolius die samestelling en die
interaksie netwerk struktuur van blom-besoekers en plant gemeenskappe negatief geraak.
Die feit dat OGKs ongeplant gelaat word, is positief vir die bewaring van biodiversiteit in Suid-
Afrika. Navorsing dui aan dat hierdie gebiede suksesvol is om te help met die bewaring van
biodiversiteit en ekosisteemfunksionering. As gevolg van die positiewe invloed van OGKs op
bewaring in gefragmenteerde en omskepte landskappe, is dit krities dat hierdie areas ongeplant
bly. Egter, die gevolge van steekdoring inval is meer intens binne OGKs as binne beskermde
gebiede, en daarom moet dit 'n prioriteit wees om hierdie gebiede ongestoord te hou. R.
cuneifolius se verwoestende uitwerking op ekosisteem funksie en netwerk struktuur was baie
duidelik. Dit is ook 'n kategorie 1 indringerplant in Suid-Afrika, en sy verwydering word deur
is die wet vereis. Daarom moet die verwydering van steekdoring ‘n bestuursprioriteit wees.
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Biodiversity value of grassland ecological networks in afforested areas, KwaZulu-Natal, South AfricaJoubert, Lize 03 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The current biodiversity crisis requires creative initiatives for mitigating further
biodiversity loss. The use of ecological networks (ENs) is such an initiative. The South
African forestry industry recognizes that there is loss of biodiversity at the smaller patch
scale, while attempting to mitigate this loss at the landscape scale by implementing largescale
ENs.
The aim of this study was to determine how representative grassland biodiversity in
ENs are of similar habitat in a nature reserves (NR). The study was conducted in the northeast
of the KwaZulu-Natal Province, adjacent iSimangaliso Wetland Park, which is a natural
World Heritage site. A systematic approach compared a wide range of taxa, namely plants,
decomposition macrofungi, vertebrates (birds and large mammals) and faunal manifestations
(e.g. molehills, dung and ant nests) between the EN and nature reserve, while controlling for
differences in disturbance regime. Species richness was compared using Mann-Whitney U
tests, while differences in species composition were determined using Correspondence
Analyses, Multi-Dimensional Scaling and Analyses of Similarity.
Grassland ENs had significantly less plant species. In addition, there were differences
in plant and fungi species composition. Differences were probably caused by (1) degree of
isolation i.e. proximity to source habitat patches in the surrounding matrix, and (2) habitat
quality. Habitat quality was determined by local disturbance regimes (e.g. grazing and fire)
and plantation-induced drought for plants, and size and amount of coarse woody debris for
fungi. In addition, significant differences in abundances of mole hills (NR>EN) and small
mammal burrows (EN>NR) might have had an effect on succession and regeneration of plant
communities.
There were differences in plant species composition between grassland EN and that at
the adjacent nature reserve. However, differences between EN and NR were small when
compared to differences between habitat types at the landscape spatial scale. It is concluded
that grassland ENs among forestry plantations contribute to biodiversity conservation in the
commercially-productive landscape. This approach to land use planning should be explored
for other commercial land uses. / AFRIKAANSE OPSOMMING: Die huidige biodiversiteitskrisis vereis kreatiewe strategieë om ‘n verdere verlies in
biodiversiteit te bekamp. Ekologiese Netwerke (EN’e) is een voorbeeld van sulke kreatiewe
strategieë. Die Suid Afrikaanse bosbou-industrie erken die verlies in biodiversiteit wat
kenmerkend in plantasies gevind word. Implementering van grootskaalse EN’e kan egter die
verlies aan biodiversiteit, wat in plantasies ondervind word, temper.
Die doel van hierdie studie was om vas te stel hoe goed biodiversiteit in grasveld EN’e
soortgelyke habitat in ‘n nabygeleë natuurreservaat verteenwoordig. Die studie was uitgevoer
in die noordooste van KwaZulu-Natal, langs iSimangaliso Wetland Park wat ‘n
wêrelderfenisgebied is. Ons het ‘n stelselmatige benadering gevolg waartydens ‘n wye
verskeidenheid taksa, naamlik plante, makro-fungi, vertebrate (groot soogdiere en voëls) en
tekens van diere-aktiwiteit (bv. miersneste, dieremis en molshope), in die EN vergelyk is met
die van ‘n natuurreservaat terwyl ons vir verskillende versteuringe gekontrolleer het.
Spesiesrykheid is vergelyk met Mann-Whitney U toetse terwyl verskille in
spesiessamestelling vasgestel is met Correspondence Analyses, Multi-Dimensional Scaling en
Analyses of Similarity.
Daar was ‘n statisties beduidende verskil in die hoeveelheid spesies tussen grasveld
EN’e en die natuurreservaat. Grasveld EN’e het minder plant spesies gehad. Boonop was daar
verskille in die samestelling van plant en fungi gemeenskappe. Verskille was waarskynlik
veroorsaak deur (1) isolasie of die hoeveelheid nabygeleë habitatbronne in die omliggende
omgewing, en (2) habitat kwaliteit. Habitat kwaliteit word bepaal deur versteuringe (bv. brand
en beweiding) en die uitdrogingseffek van plantasies vir plante, en die hoeveelheid en grootte
van growwe houtagtige puin vir fungi. Daar was ook beduidende verskille in die hoeveelheid
molshope (NR>EN) en klein soogdier gate (EN>NR), wat moontlik ‘n effek kon hê op
suksessie en herstel van plantgemeenskappe.
Daar was verskille in plantspesiessamestelling tussen grasveld EN’e en die van die
langsliggende natuurreservaat. Hierdie verskille was egter klein wanneer dit vergelyk word
met die verskille tussen verskillende soorte habitatte in die landskap. Daarom kom ons tot die
gevolgtrekking dat grasveld EN’e tussen bosbouplantasies bydra tot die bewaring van
biodiversiteit in kommersiële landskappe. Hierdie benadering tot grondgebruik behoort verder
verken te word vir ander kommersiële bosbou en boerderypraktyke.
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