The content of this thesis is to determine the current state of secondary succession of trees in the southwestern part of Ethiopia, in the surroundings of Lake Awassa, on the slopes of Kebele (the smallest administrative unit in Ethiopia) Umbullo Kajima and implementation of the coppicing experiment of the species Acacia saligna. After the elaboration of the methodology, the research of both parts of the work was carried out. The field research itself has been running since 17. 7. 2016 to 08. 08. 2016. In the research section focused on secondary succession, the occurrence of native species and the successful extension of plantations from the past project years were found. For Acacia saligna was confirmed coppicing ability.

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Thesis (MScAgric (Soil Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The sandy soils of the Riverlands Nature Reserve, near Malmesbury, and the neighbouring farm were studied to determine the effects of long term invasion of the legume Acacia saligna on the soil nutrient content of a soil previously vegetated with fynbos. The effect of the removal of this alien legume on general soil properties and groundwater quality were also studied. The changes in nitrates and nitrites (NOX) due to the invasion and removal of the alien legume were investigated in more detail than changes in other soil nutrients. In addition to that emphasis was placed on the effect of vegetation clearing on groundwater quality, specifically relating to potential contamination with nitrates. This study was initiated after Conrad et al., (1999) found increased NOX concentrations in ground water while studying the effects of pig farming on ground water nitrogen (N) near a site cleared of Acacia saligna by Working for Water (WFW). Since many sites are scheduled for removal of this alien vegetation it was deemed necessary to study the effects that clearing alone had on groundwater quality. It was suspected that there would be an increase in soil and groundwater NOX with vegetation removal due to the inputs from the legume alien invader. Soil sampling was done continuously throughout the rainy season of 2007 (From May to December) on three adjacent sites separated by some 50 m of distance, consisting of a natural fynbos site and two Acacia saligna sites. The sites were selected approximately on the same contour line to prevent interaction through lateral water flow. One of the Acacia sites was cleared by the Working for Water programme in the usual manner leaving slash on the ground. Soil samples were collected at regular intervals throughout the season from all three sites (fynbos, Acacia and cleared site) using a Jarrett soil auger. They were airdried (to achieve full oxidation of mineral N) and sieved though a 2mm sieve. Soils were analysed by atomic absorption spectroscopy for basic cations and by ion chromatography for anions, including nitrates and nitrites. Total carbon and nitrogen was determined by combustion, pH (1M KCl and H2O) and EC (1:5 H2O) were also measured. The present study was part of a wider investigation into the quality of groundwater, modelling flow and contaminant transport (Jovanovic et al., 2008). The largest changes in soil properties were observed in the top (0-5 cm) layer. The fynbos site had a lower nutrient status by comparison to the Acacia site and the cleared site. The sum of cations from the soils of the fynbos site at a soil depth of 0-5cm was 100mg/kg and soils from the cleared and Acacia sites were about 190mg/kg. The Acacia site had a higher NOX status and experienced a larger NOX fluctuation during the rainy season than the fynbos site; minimum NOX values were similar (below 10mg/kg) but the Acacia site had a maximum NOX value of near 60mg/kg and the fynbos site just below 30mg/kg. There was little difference in general soil characteristics (exchangeable cations, pH and EC, total soil C and N) during the first season after clearing, between the Acacia and the cleared sites. The effect of soluble nitrogen changes due to alien legume invasion and removal on groundwater quality, relating to NOX, during the first season after clearing, was determined. It was found that the Acacia site had higher NOX concentrations than the fynbos site. At 0-5cm the fynbos site NOX was less than 30mg/kg and the Acacia site was between 30 and 110mg/kg for most of the season, with values lower than 30mg/kg for the last four sampling dates only. N concentrations on the cleared site behaved in a similar manner to the uncleared Acacia site, but generally N values were lower on the cleared site, there were only two sampling dates where the cleared site had higher NOX values than the Acacia site at 0-5cm. The average groundwater N in NOX under the cleared site was 4.34 mg/l, and under the Acacia site 3.78mg/l, these values are both below the level determined for water contamination with nitrates. However, the increase in ground water nitrate levels after A. saligna clearing was significant. It was concluded that there is a change in the nutrient status of soil with Acacia invasion and again with removal. NOX migrates to the groundwater to a larger degree once vegetation has been removed, although during this study the nitrate pollution threshold of 10 mg/l nitrate N was not reached. / AFRIKAANSE OPSOMMING: Die sanderige gronde van die Riverlands Natuur Reservaat, naby Malmesbury, en die aangrensende plaas was bestudeer om die effek van die langtermyn indringing van die peulgewas, Acacia saligna, op die voedingswaarde van ‘n voorheen fynbos begroeide grond, sowel as die effek van die verwydering van die indringer op die algemene samestelling van die grond en grondwater kwaliteit. Oplosbare stikstof veranderings (NOX) wat plaasvind as gevolg van die indringing en verwydering van die indringer peulgewas, was in meer diepte bestudeer as die ander elemente. Klem was ook geplaas op die effek van die verwydering van plantegroei op grondwater kwaliteit, met spesifieke verwysing na potensiële nitraat besoedeling. Die studie was beplan na Conrad et al., (1999) ‘n toename van NOX konsentrasies in grondwater ontdek het, tydens ‘n studie van die effek wat vark boerdery het op grondwater N naby ‘n area waar Acacia Saligna verwyder was deur Working For Water (WFW). As gevolg van die feit dat verskeie areas in die proses is om skoongemaak te word van Acacia Saligna, is dit nodig geag om die effek daarvan of grondwater kwaliteit te ondersoek. Die hipotesis was dat daar ‘n toename in NOX konsentrasies in grond en grondwater sal wees as gevolg van die verwydering van plantegroei. Grond monsters was deurlopend geneem gedurende die reën seisoen van 2007 (Vanaf Mei tot Desember) uit nabygeleë areas wat omtrent 50 meter uitmekaar is. Die volgende tipes grond was verteenwoordig: ‘n Fynbos begroeide grond sowel as ‘n grond begroei met Acacia saligna. Die areas was geselekteer ongeveer op die selfde kontoer lyn om interaksie tussen areas te voorkom as gevolg van laterale water vloei. ’n Gedeelte van die A. saligna area was skoongemaak deur die Working for Water program op die gewone manier deur die afgesnyde plant materiaal op die grond te los. Grond monster was geneem met gereelde intervalle gedurende die seisoen op al drie areas (fynbos, A. saligna, en skoongemaakte area) deur die gebruik van ’n Jarret grondboor. Die monsters was lugdroog gemaak (om volle oksidasie van die mineraal N te verseker) en toe gesif deur ‘n 2mm sif. Die gronde was analiseer deur atoom absorpsie vir basiese katione en deur ioon chromatografie vir anione, insluitende nitriete en nitrate. Totale koolstof en stikstof was bepaal deur verbranding terwyl pH (1M KCl en H2O) en EC (1:5 H2O) ook gemeet was. Hierdie studie was deel van ‘n wyer ondersoek na die kwaliteit van grondwater, vloei modelering en vervoer van kontaminante (Jovanovic et al., 2008). Die grootste veranderinge in die grond eienskappe was in die boonste grondlaag (0-5cm) waargeneem. Die bevinding was dat die fynbos area ‘n laer voedingswaarde het as die area begroei met die indringer sowel as die die skoongemaakte area. Die som van katione onder fynbos grond by ‘n grond diepte van 0-5cm, was 100/mg/kg en die som van katione by die ander twee areas was omtrent 190mg/kg. Die Acacia area het ‘n hoër NOX inhoud en het ‘n groter NOX fluktuasie ervaar gedurende die reën seisoen as die fynbos area. Die minimum NOX waardes was soortgelyk (minder as 10/mg/kg), maar die Acacia area het ‘n maksimum NOX waarde van omtrent 60mg/kg terwyl die fynbos area se maksimum net minder as 30mg/kg gehad het. Daar nie veel verskil tussen die algemene grond eienskappe (uitruilbare katione, pH en EC, totale C en N) van die Acacia en skoongemaakte areas gedurende die eerste seisoen na die indringer verwyder is nie. Die effek van oplosbare stikstof veranderings as gevolg van die peulgewas se indringing en verwydering op grondwater kwaliteit, met verwysing na NOX, gedurende die eerste seisoen na verwydering van die indringer was bepaal. Dit was bevind dat die Acacia area ‘n hoër NOX konsentrasie as die fynbos area het. Op ‘n diepte van 0-5cm was die fynbos NOX laer as 30mg/kg terwyl die Acacia area tussen 30 en 110mg/kg vir die grootste gedeelte van die seisoen was met waardes laer as 30mg/kg vir die laaste vier datums waarop monsters geneem was. Veranderings in N op die skoongemaakte area en die Acacia area was soortgelyk, maar oor die algemeen was N waardes laer op die skoongemaakte area. Daar was slegs op twee datums gevalle gevind waar die skoongemaakte area ‘n hoër NOX inhoud as die Acacia area gehad het by ‘n diepte van 0-5cm. Die gemiddelde N in NOX in die grondwater onder die skoongemaakte area was 4.34mg/l en by die Acacia area was dit 3.78mg/l; hierdie waardes is onder die drempel vir nitraatbesoedeling in grondwater. Die nitraat inhoud van die grondwater het wel beduidend toegeneem as gevolg van verwydering van A. saligna. Die gevolgtrekking was dat daar ‘n verandering plaasvind in die voeding status van grond met Acacia saligna indringing en weer met verwydering. NOX migrasie na die grondwater verhoog met verwydering van plantegroei. In hierdie studie was die nitraat besoedeling drempel van 10mg/l nitraat N nie bereik nie.

Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / The fynbos eco-region in the Western Cape lowlands has been extensively transformed by anthropogenic activities such as agriculture and urban development, as well as invasive alien plants. Elandsberg Private Nature Reserve and Farms lies on Swartland Alluvium Fynbos and has been largely fragmented by agricultural crop production, whilst Riverlands Nature Reserve together with the Pella Research Site, which lie on Atlantis Sand Fynbos, are under severe threat from the invasive woody alien Port Jackson Willow (Acacia saligna) which forms dense stands in the lands adjacent the nature reserve. Habitat transformation has resulted in subsequent loss of habitat and a reduction in habitat value for small mammal communities by creating a mosaic of optimal and sub-optimal habitats. The success of A. saligna is, in part, attributed to its production of copious amounts of small hard-shelled seeds and well established soil seed banks. In the first part of this study we investigated the effect of habitat transformation on resident small mammal communities by comparing small mammal species richness, diversity and abundance between natural and transformed habitats as well as between the two vegetation types. We also investigated the population demographics of the striped mouse (Rhabdomys pumilio) in the different habitats. Our study shows that whilst fragments of natural habitats, especially at Riverlands and Pella, may be playing an important role in harbouring rare and possibly endangered species, transformed habitats are also important as secondary habitats providing both cover as well as seasonal food resources. Reproduction and body condition in R. pumilio were dependent on seasonal changes such as availability of water and food resources in the habitats. The second part of this study was carried out to investigate the effect of alien plant invasion on the resident small mammal communities at Riverlands Nature Reserve and to determine the role of small mammals in the removal and predation of A. saligna seeds. Rodent species richness, diversity and abundance were very low in the A. saligna stands compared to the adjacent fynbos vegetation. The interaction of rodents with seeds (removal or predation) was dependent upon seed size and seed abundance in the habitats. Whilst rodents may play an important role in predator limitation in the acacias, it is also possible that they may be playing a significant role in dispersing the seeds of acacias into the fynbos. More work is required to fully understand the role small mammals play in seed predation, dispersal and limitation in alien invaded fynbos systems.

The aim of this diploma thesis is tree planting method comparison of water retention improving technology (Improve pits) and non-improving technology (Pits). Research was realized on the „Sustainable management of soil, forest and water resources as the pilot model for the rural development in SNNPRS, Ethiopia“ project areas. This project was realized by Mendel university in Brno. Terrain investigations, experimental plot set up and soil sample collection and analyses were realized by devised methodology. Terrain works took a place during July and August 2016. When comparing resulting values, it became clear that the Improve pits technology shows positive effect on soil water retention capacity and its gradual release. This effect creates more suitable conditions for regeneration of damaged vegetation.