Developing consistent and repeatable broad-scale methods for biodiversity modelling is an important goal to address as habitat loss, fragmentation and environmental degradation threaten our ability to maintain ecosystem and species diversity levels. Geospatial reviews of biodiversity monitoring have identified ecological indicators for the indirect mapping of species richness and ecosystem components modelling the processes controlling species distribution gradients. The goal of our research is to advance broad-scale biomonitoring by demonstrating how landscape-scale environmental indices can be used to model regional ecosystem and species diversity of British Columbia (BC), Canada. We meet our ecosystem-modelling goal by selecting and developing suitable ecological indicators from Earth observation data and terrain indices to represent the structure, composition and function of the environment, displaying both static and dynamic landscape processes of BC’s ecosystems. We regionalize the selected indirect indicators of biodiversity using a two-step clustering algorithm. The results display 16 ecologically distinct terrestrial ecosystems, 10 of which characterize the northern Boreal, coastal and Southern Interior mountain regions, and six represent the coastal lowlands, interior, Georgia Depression, Boreal and Taiga Plains of British Columbia. Comparing our classification to BC Ministry of Forests biogeoclimatic zone mapping, we find spatial similarity in the coastal, Taiga and Boreal Plains. Overall, our classification distinguishes a greater diversity of ecosystems in the mountainous regions of the province and greater homogeneity in the Central Interior where our landscape characteristics represent current productivity conditions. Our approach to ecosystem modelling supports legacy mapping by providing ecological information in under-sampled regions of BC and offers a method for consistent repeat modelling of ecosystem diversity to identify landscape change. To meet our species-modelling goal we employ a flexible non-parametric regression tree model (Random Forests) to establish the power of landscape-scale indicators (productivity, ambient energy, and heterogeneity) to predict the spatial distribution of breeding bird richness and establish the dominant landscape processes controlling vertebrate richness throughout BC. Our models explain approximately 40% of the variation in survey effort stratified breeding bird species richness levels and distinguish ambient energy as the top ranked environmental predictors of breeding richness. Using our modelled relationships, we forecast breeding richness levels for the regions of BC not currently surveyed to support conservation management of birds and vertebrate species. The results identify the lowland, warm and dry regions of the Boreal, Taiga, South and Central Interior and the Georgia Depression to be species rich. These results have implications for conservation managers, as high breeding richness is also concentrated in the areas favourable to human settlement. Additionally, by connecting breeding bird data derived from remotely sensed data and continuously collected climate data, we provide an approach for monitoring ecological indicators as surrogates of vertebrate population levels over broad spatial scales. / Graduate

Doctor of Philosophy / Department of Biology / Keith B. Gido / Global climate change could lead to less frequent but more severe precipitation events in the Great Plains, altering the hydrologic regimes of streams. It is important to quantify species roles in these dynamic systems, because changes in stream communities are likely to accompany predicted changes in hydrology. The effects of species on ecosystem processes also are limited by the frequency of disturbance, because prairie streams are harsh, nonequilibrium systems characterized by a wide range of disturbances. In particular, frequent floods that reset the ecosystem to an early successional state can override the influence of consumer populations because the availability of resources is too unpredictable to maintain stable populations of those species or because species are absent following the flood. As flood frequency decreases, potential consumer effects may intensify. Using a combination of field and experimental stream mesocosm experiments, I (1) characterized the ecosystem effects of southern redbelly dace (Phoxinus erythrogaster), a grazing minnow, (2) tested the interactive effects of flood frequency and the presence of water column (red shiner; Cyprinella lutrensis) or grazing minnows (Phoxinus) on ecosystem processes, and (3) tested the effects of species loss from the grazer functional feeding group on stream ecosystem structure and function. I found that dace affected some aspects of ecosystem structure but not function, which suggested that grazer effects in prairie streams may not be consistent across taxa. In the context of flood frequency, both the water column omnivore and dace affected recovery of prairie stream primary producers following flooding disturbance by stimulating production, presumably through nutrient remineralization. However, some of these effects were transient or dependent on flood frequency, and my results indicate that consumer effects depend not only on environmental venue but also on the balance between consumptive losses and nutrient stimulation. In a comparison of the effects of removing different taxa from a grazer assemblage, the loss of crayfish, snails, or dace from a grazer assemblage did not differentially affect ecosystem processes, suggesting overlap in the ecosystem roles of these species in the context of this experiment.

M.Ed. / This study, entitled "Stakeholders Perceptions about their Educational Contributions of GNP in Mozambique" focused on stakeholders of Nhambita buffer zone in the Province of Sofala. My interest in conducting such an investigation stemmed from the fact that when started this research I was working at the center for sustainable development of natural resources (CDS-RN) in Chimoio. — Manica Province and had Gorongosa National Park (GNP) as our pilot project. I realized that there were different stakeholders involved with the Park as well as the communities around it and not that much was done to improve their quality of life. Therefore, there was a need to conduct an inquiry which could lead to identifying the real reason underpinning the stakeholders not to do much and to afterwards draw some conclusions to modify the methodologies in order to change stakeholders' perceptions. In this regard, I conducted interviews and questionnaires in the community and with some stakeholders at Nhambita community, followed by data analysis of research data representing the stakeholders, community members, GNP and also to empower all participants. Hopefully, an educational programme would result from the consensus among all interested parties in the process with the objective of improving the citizen's life.

Despite advances in Earth observation and modeling, estimating tropical biomass remains a challenge. Recent work suggests that integrating satellite measurements of canopy height within ecosystem models is a promising approach to infer biomass. We tested the feasibility of this approach to retrieve aboveground biomass (AGB) at three tropical forest sites by assimilating remotely sensed canopy height derived from a texture analysis algorithm applied to the high-resolution Pleiades imager in the Organizing Carbon and Hydrology in Dynamic Ecosystems Canopy (ORCHIDEE-CAN) ecosystem model. While mean AGB could be estimated within 10% of AGB derived from census data in average across sites, canopy height derived from Pleiades product was spatially too smooth, thus unable to accurately resolve large height (and biomass) variations within the site considered. The error budget was evaluated in details, and systematic errors related to the ORCHIDEE-CAN structure contribute as a secondary source of error and could be overcome by using improved allometric equations.

Magister Scientiae - MSc (Biodiversity and Conservation Biology) / Arundo donax is an invasive species that mostly impacts on sensitive riparian ecosystems. Arundo is also invasive in South Africa, though less is known about its ecology, biology, and impacts. Since California and the Western Cape of South AFrica have similar Mediterranean-type climates, we could assume that the impacts of Arundo on ecosystems in California are likely to be similar in the Western Cape, and that control methods used could be extrapolated for use in South Africa. This thesis attempted to determine what impact Arundo has on biodiversity at the community-ecosystem level. / South Africa

The presence of green spaces in cities has been increasingduring recent years. The aim of this thesis is to understand the importance of these areas in the city through the ecosystem services approach, and to provide an example on how that approach is undertaken in two different European cities: Madrid and Stockholm. By using Geographic Information Systems, interviews with planning representatives in both countries, and planning documents, it was found that even though this approach is known and mentioned in both cases, the outcome in the distribution and accessibility of these areas varies widely from one study area to another.

Cette thèse étudie par trois modèles et une expérience les effets des interactions entre le réseau vert (basé sur la production primaire) et brun (basé sur la décomposition) sur le fonctionnement des écosystèmes. Trois interactions entre les deux réseaux sont étudiées: 1) les nutriments recyclés par tous les organismes couplent les réseaux verts et bruns par une relation de mutualisme/compétition entre les producteurs primaires et les décomposeurs; 2) les consommateurs généralistes se nourrissent de proies des deux réseaux trophiques et 3) les connexions spatiales par les consommateurs généralistes mobiles en haut des réseaux trophiques et les flux de nutriments et de détritus en bas. Les résultats montrent que ces interactions peuvent affecter le fonctionnement des écosystèmes y compris les cascades trophiques, la stabilité et l'importance relative de la chaîne verte et brune. Ces résultats conduisent à (1) de nouvelles perspectives sur la modélisation du fonctionnement des réseaux trophiques, (2) des prédictions originales, (3) des nouvelles interprétations de résultats empiriques, (4) des idées sur des différences fondamentales de fonctionnement entre types d’écosystèmes, (5) des prédictions sur la réponses des écosystèmes aux changements globaux. / This thesis studies through three models and an experiment the important effects of the interactions between the green (based on primary production) and brown (based on decomposition) food webs on ecosystem functioning. Three interactions between the two food webs are studied: 1) nutrients recycled from all organisms in the food web couple the green and brown food webs through mutualistic/competitive interaction between primary producers and decomposers; 2) generalist consumers feed on prey from both food webs; and 3) the spatial connections between the two food webs through mobile generalist consumers at the top and through nutrient and detritus fluxes at the bottom of the food webs. The results show that these interactions may affect the ecosystems functioning including trophic cascades, stability and the relative importance of green and brown food chains. These results lead to new (1) insights on the way to model food webs, (2) predictions on food web functioning, (3) interpretation of empirical results, (4) ideas to compare the functioning of different ecosystem types and (5) predictions on food web responses to global changes.

Résumé confidentiel / Résumé confidentiel

The seed bank dynamics of five habitats as well as a grazing gradient in the southwestern Kalahari, South Africa were studied. Soil samples were collected in the following habitats: dune crests, dune slopes, dune streets, a calcrete outcrop and a riverbed on the farm Alpha. Soil samples were also collected along a grazing gradient from a watering point. Three methods of soil seed bank analysis were used to analyse the soil samples and to gain insight into soil seed bank response to habitat type and to grazing pressure, over four seasons in the year 2004. Results from the three methods of analysis were also compared to each other. They included the direct seedling germination method, the seedling germination re-examination and the seed extraction method. These analyses were used to (a) estimate seed bank size and composition in response to habitat type and grazing pressure; (b) the differences between the standing vegetation- and the seed bank-flora in different habitats and along a grazing gradient and (c) the type of seed banks that tend to form in certain habitats and in response to grazing pressure. Analyses of soil seed bank size along a grazing gradient showed that the seedling emergence re-examinations estimated a larger size for the seed bank than the direct seedling emergence method. The seed extraction method estimated a significantly larger seed bank size than the other two methods. Heavy grazing pressure favoured annual/opportunistic species such as Schmidtia kalahariensis, which formed very large seed banks in heavily trampled areas. When Schmidtia kalahariensis data was removed from the seed bank analyses, it was found that, in contrast to previous results, the direct germination method mostly estimated a larger seed bank size than the re-examination. Also, the estimation of seed bank size by the flotation method, in this case, was much smaller. The flotation method produced data mostly for hard-seeded species, while the seedling emergence method produced data for species with small seeds and which were readily germinable. In all seasons, the dune crest habitat always had the smallest seed bank and the riverbed habitat always had the largest seed bank. All the dune habitats were characterised by perennial grasses. Perennial grasses formed transient seed banks which were relatively small. The riverbed habitat’s vegetation was mostly composed of annuals. Annual plants formed persistent seed banks which were relatively large. Species richness of the readily germinable seed bank in all habitats, fluctuated between the four seasons and was usually largest in summer. The difference in species richness between the above- and belowground floras fluctuated over four seasons. The dune habitats showed a large difference between the species richness of the above- and the below-ground flora, while the riverbed habitat showed a much smaller difference. The dune habitats had many species with transient seed banks while the riverbed was characterised by many species with short-term persistent and ‘permanent’ seed banks. / Dissertation (MSc)--University of Pretoria, 2011. / Plant Science / unrestricted

Abstract The degradation of rivers and streams has led to world-wide efforts to restore freshwater habitats. A good understanding of the social-ecological context is considered key to successful restoration. In this thesis, a multidisciplinary framework was applied to study ecological and social dimensions of restoration success. First, the long-term performance of in-stream restoration measures was examined by conducting repeated cross-sectional surveys in restored streams up to 20 years post-restoration. Next, nationwide electrofishing data were used to assess the density responses of juvenile salmonids to habitat restoration and factors influencing restoration success were examined. Finally, changes in the provision of ecosystem services were evaluated by comparing the perceptions of restoration outcomes between two user groups and three study rivers. The results indicated that the restoration-induced increase in habitat heterogeneity persisted over time, initiating an overall positive development also in biological metrics (i.e. juvenile salmonids and aquatic mosses). However, overall substrate variability in restored streams remained lower than in near-pristine streams, with a shortage of gravel beds. Fish responses varied strongly between rivers, which was explained mainly by watershed scale (e.g. river basin size, dominant geology) and local (potential interspecific competition) factors. Site-specific differences were also observed in the delivery of ecosystem services, mainly reflecting stakeholder perceptions of landscape value and fish provisioning. Overall, the results show that setting indicators and target levels for restoration success is grounded on perspective. Socially conscious ecological restoration that acknowledges local specialities and needs in priority setting, planning and implementation has the potential to provide multiple benefits for river ecosystems and society. / Tiivistelmä Virtavesien ekologisen tilan heikentyminen on johtanut maailmanlaajuisiin toimiin niiden elinympäristöjen kunnostamiseksi. Usein ekologisen kunnostuksen onnistuminen edellyttää kuitenkin ihmisen ja ympäristön vuorovaikutussuhteiden laaja-alaista ymmärtämistä. Tässä väitöskirjatutkimuksessa käytettiin monitieteistä viitekehystä virtavesikunnostusten ekologisten ja sosiaalisten vaikutusten tutkimiseen. Ensimmäisessä osatyössä arvioitiin kunnostustoimenpiteiden kestävyyttä sekä uoman rakenteellisen monimuotoisuuden kehittymistä pitkällä aikavälillä (10-20 vuotta kunnostusten jälkeen). Toisessa osatyössä tehtiin valtakunnallisen sähkökalastusaineiston avulla meta-analyysipohjainen yhteenveto suomalaisten virtavesikunnostusten vaikutuksista taimenen ja lohen kesänvanhojen (0+) poikasten tiheyteen sekä tutkittiin kunnostustulokseen vaikuttavia ympäristötekijöitä. Kolmannessa osatyössä selvitettiin kunnostusten onnistumista ekosysteemipalvelujen näkökulmasta vertaamalla kahden eri käyttäjäryhmän kokemia muutoksia kolmen tutkimusjoen välillä. Väitöskirjan tulokset osoittivat, että kunnostukset lisäsivät jokiuoman rakenteellista monimuotoisuutta sekä lyhyellä että pitkällä aikavälillä ja vaikuttivat myönteisesti myös biologisiin indikaattoreihin (lohikalojen poikastiheys ja vesisammalet). Vaihtelu pohjan laadussa oli kuitenkin luonnontilaisia uomia vähäisempää ja erityisesti kutuun soveltuvaa soraa oli niukasti. Lohikalojen tiheysvaste vaihteli voimakkaasti jokien välillä, mikä selittyi pääasiassa valuma-alueeseen liittyvillä (esim. valuma-alueen koko ja geologia) ja paikallisilla (mahdollinen lajien välinen kilpailu) tekijöillä. Paikkasidonnaisia eroja havaittiin myös vaikutuksissa ekosysteemipalveluihin ja ne heijastivat etenkin maisemassa ja kalasaaliissa koettuja muutoksia. Tutkimus osoitti, että erilaiset taustat ja odotukset vaikuttavat vahvasti siihen, millaisten kriteerien perusteella kunnostusten onnistumista arvioidaan. Jotta kunnostuksilla saavutettaisiin hyötyjä sekä jokiekosysteemeille että yhteiskunnalle, on tärkeää tuntea paikalliset erityispiirteet ja -tarpeet ja ottaa ne huomioon kunnostuskohteiden valinnassa sekä toimenpiteiden suunnittelussa ja toteutuksessa.