Assembly is a process that shapes the abundance and identity of species in a community. Niche and neutral theory explain assembly processes with mechanisms driven by either species differences, or functional equivalence and stochastic dispersal. In 2017 I sampled vegetation and environmental variables at 59 sites in the Noxubee National Wildlife Refuge and Tombigbee National Forest of Mississippi to explore forest understory community assembly. I developed and assessed a framework of predictions concerning general patterns and underlying mechanism. Evidence of dispersal limitation and functional equivalence were expected under neutral theory. Local environmental characteristics, surrounding landscape variables, and fire were significant determinants of beta diversity. Dispersal was not a strong predictor of beta diversity. I found evidence of both niche complementarity and functional equivalence, as well as niche differences among common vines and an introduced vine (Lonicera japonica). Overall, the results were more congruent with predictions expected under niche theory.

Thesis (MSc) -- University of Stellenbosch, 2004. / ENGLISH ABSTRACT: This thesis focuses on the effects of vegetation resting on biodiversity and community dynamics at Rocherpan Nature Reserve (320 36'S, 180 18'E) in the semi-arid coastal strip of the Succulent Karoo known as Strandveld. As a whole, the Succulent Karoo has an extraordinary high level of phyto diversity with high levels of endemism. This is particularly true for succulent shrubs belonging to the groups Mesembryanthemaceae, Crassulaceae and Asteraceae. The thesis begins with an investigation into effects that vegetation resting has on plant diversity. The aim was to determine if resting affected biodiversity levels and if so, which plant groups are affected and why. Through a numerical approach, it was determined that with resting overall species richness remained the same. However, different plant life forms responded to resting differently. With increased resting, abundance of succulent shrubs decreased, while richness of annuals increased. The second aspect under investigation was to determine how resting the vegetation affected community dynamics. The aim was to understand how vegetation structure and interspecific associations changed with resting and to apply these findings to known community models. Through an autocorrelation approach, it was found that horizontal patterning of long-lived woody species, that formed distinctive vegetation clumps, did not change with resting, while differences were found in woody matrix species and succulent species. These changes in structure were investigated further through a study on the demography of specific species. Demography of woody species associated with vegetation clumps did not change with vegetation resting, while significant changes were observed for woody matrix species and succulent species. In longer rested vegetation, woody matrix species showed a greater range in size class distribution (i.e. had both very large and smaller plants) with the tendency towards larger plant sizes. Succulents on the other hand, had a smaller range in size class distribution with a tendency towards larger plants. For all species investigated there were low seedlings counts. It was concluded that succulent shrub populations were 'mature' and continued resting could result in local extinction of some species due to the lack of regeneration. The overall lack of seedlings was attributed to a saturated establishment environment. Implications for conservation management were discussed. / AFRIKAANSE OPSOMMING: Hierdie tesis fokus op die gevolge van plantegroeirus op biodiversiteit en gemeenskapsdinamika by die Roeherpan Natuurreservaat (320 36'S, 180 18"0) in die halfdor kusstrook van die Sukkulente Karoo, bekend as die Sandveld. In die geheel gesien het die Sukkulente Karoo 'n buitengewone hoë vlak plantdiversiteit met hoë vlakke endemie. Dit is veral waar vir sukkulente struike wat tot die groepe Mesembryanthemaceae, Crassulaceae en Asteraceae behoort. Hierdie tesis ondersoek eerstens die gevolge wat plantegroeirus op plantdiversiteit het. Die doel was om te bepaal of rus die biodiversiteitsvlakke beïnvloed het en indien wel, watter plantgroepe en waarom. Deur middel van 'n numeriese benadering is bepaal dat die algehele diversiteit, numeries gesproke, met plantegroeirus dieselfde gebly het. Verskillende plantlewensvorme het egter verskillend gereageer. Met toenemende rus het die diversiteit van sukkulente struike afgeneem, terwyl die diversiteit van jaarplante verhoog het. Die tweede aspek wat ondersoek is, was om te bepaal hoe die plantegroeirus die dinamika van die omgewingsgemeenskap beïnvloed het. Die doel was om te verstaan hoe die struktuur van die plantegroei en die interspesifieke assosiasies verander het met rus en om dan hierdie bevindinge toe te pas op bekende gemeenskapsmodelle. Deur middel van 'n outokorrelasiebenadering is gevind dat die horisontale patrone van meerjarige houtagtige spesies wat in duidelik-uitkenbare plantegroeigroeperings voorkom, nie met rus verander het nie. Veranderinge is egter wel in die houtagtige matriksspesies en die sukkulente spesies waargeneem. Hierdie veranderinge in struktuur is verder ondersoek deur 'n studie te maak van die demografie van spesifieke spesies. Daar is gevind dat die demografie van houtagtige spesies geassosieer met plantegroeigroeperings nie met plantegroeirus verander het nie, maar beduidende veranderinge is waargeneem in die geval van houtagtige matriksspesies en sukkulente spesies. By plantegroei wat langer gerus het, het die houtagtige matriksspesies 'n wyer verspreiding in klasgroottes vertoon (d.i. daar was baie groot plante én kleiner plante) met 'n gemiddelde afname in plantgrootte. Sukkulente, aan die ander kant, het 'n kleiner verspreiding in klasgroottes vertoon met 'n neiging tot groter plante. Vir al die spesies wat ondersoek is, was daar lae saailingtellings. As gevolg van die "volwassenheid" van die populasies van sukkulente struike, sou voortdurende rus, weens die gebrek aan regenerasie, kon lei tot die plaaslike uitwissing van sommige spesies. Die algemene gebrek aan saailinge is toegeskryf aan die versadigde vestigingsomgewing. Die implikasies VIr natuurbewaringsbestuur word bespreek. v

Thesis (PhD(Agric) (Conservation Ecology and Entomology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: See full text document for abstract / AFRIKAANSE OPSOMMING: sien volteks dokument vir die opsomming

No description available.

Traditional peoples are often described as "stewards of agricultural diversity", yet little research has been conducted on the determinants of agrodiversity. This thesis focuses on agrodiversity and how peasant farmers build and maintain cultivated plant diversity in home gardens found in three distinct traditional communities along the Maranon river in the Peruvian Amazon---an upland mixed agricultural village, a lowland agricultural village, and a lowland fishing village. Data were gathered through household surveys (n = 192) and in-depth interviews (n = 112). Substantial variation in cultivated plant diversity was found among and within villages. Residents with the highest home garden agrodiversity tend to be among the wealthier households, and are more likely to have both established their own garden, and tended it for longer periods. Complex planting material exchange networks underlie the establishment and maintenance of home garden agrodiversity. The results underscore the importance of studying local variations in agricultural diversity, and exchange networks that bring agricultural planting stock to peasant farmers.

Agrobiodiversity constitutes an essential resource for traditional rural populations. Home gardens are "hotspots" of agrobiodiversity and important loci of in situ conservation efforts. This study seeks to understand the factors affecting gardeners' choices and to assess the accessibility of planting material in rural communities of the Peruvian Amazon. Household surveys and garden inventories conducted in 15 villages of the Corrientes river (n = 300), and case studies in three of these villages (n = 89), allowed to describe the local and regional patterns of garden agrobiodiversity and the structure of planting material exchange networks. Analyses reveal a strong link between species diversity and both household cultural and socioeconomic characteristics, and village ethnicity and size. Planting material flows primarily through matrilineal bonds, from advice-givers to advice-seekers, from old to young and from rich to poor. Farmers with exceptional species diversity, propensity to give and/or expertise are identified and their role in the conservation of cultivated plants is assessed. Expertise is not found to be as closely related to high species diversity as expected, but knowledge and planting stock dissemination go hand-in-hand.

La structuration spatiale de la diversité floristique constitue un outil de base pour la gestion durable des forêts tropicales. La complexité des forêts tropicales s’accommode mal des généralisations et des extrapolations qui aboutissent le plus souvent à des résultats imprévisibles. La présente étude a pour but (1) d’identifier les groupements végétaux des forêts matures de terre ferme de la RBD et partitionner la variance floristique ;(2) de comparer les forêts matures de terre ferme de la RBD à d’autres forêts tropicales sur la base de la diversité, de la structure et de la dominance des taxons; (3) d’évaluer la structuration spatiale de la diversité dans les forêts à Gilbertiodendron dewevrei de la RBD; (4) d’évaluer l’influence des densités de Raphia regalis sur la diversité des forêts matures de terre ferme de la RBD; (5) de déterminer le statut phytogéographique des forêts à Coula edulis du sud-est Cameroun ;(6) de Comparer les différents types forestiers de forêts matures de terre ferme du sud-est Cameroun sur la base de la diversité et de la structure. La Réserve de Biosphère du Dja (RBD) ainsi que le massif forestier Ngoyla Mintom font partie sont faiblement perturbés par les activités anthropiques et font partie de l’initiative de conservation transfrontalière TRIDOM. La variance floristique dans la RBD est principalement expliquée par les distances géographiques, l’indice de continentalité et la topographie. La part de variance floristique non expliquée est élevée et due aux facteurs stochastiques et à l’hétérogénéité environnementale non détectée. La diversité locale dans les forêts matures de terre ferme de la RBD est élevée, bien que n’atteignant pas les degrés extrêmes observés dans certaines forêts tropicales d’Asie et d’Amérique du Sud. La diversité de différenciation est faible et positivement corrélée aux distances géographiques. Quelques taxons sont dominants tandis que le nombre d’espèces rares est élevé. Dans les forêts à Gilbertiodendron dewevrei, les strates arborescentes sont moins diversifiées que celles des forêts hétérogènes aussi bien à l’échelle locale qu’à celle du site. A surface égales, les strates herbacées des forêts monodominantes sont aussi diversifiées que celles des forêts hétérogènes. La diversité de différenciation est négativement corrélée à l’amplitude de la monodominance et aux distances géographiques même en absence des effectifs de Gilbertiodendron dewevrei. Raphia regalis influence négativement les densités dans les strates arborescentes, contribuant ainsi à une diversité locale artificiellement élevée. Les forêts à Coula edulis du sud-est Cameroun correspondent à la continuité de la partie continentale du bas-guinéen. Le district congolais du Dja suit les contours de la rivière dont il porte le nom. Les types forestiers matures de terre ferme du sud-est Cameroun diffèrent aussi bien du point de vu de leur structure que de leurs diversités à différentes échelles. Toute intervention doit tenir compte des spécificités de chacune d’entre elles. Les taux élevés d’espèces rares et la faible diversité des forêts à Gilbertiodendron dewevrei, l’isolement relatif des forêts à Coula edulis du district congolais du Dja, les faibles densités d’espèces arborescentes dans les forêts à Raphia regalis et le statut conservatoire de l’espèce dominante, la diversité élevée des forêts mixtes à l’échelle du sud-est Cameroun et du bassin du Congo. / Doctorat en Sciences agronomiques et ingénierie biologique / info:eu-repo/semantics/nonPublished

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-01-20T23:17:07Z No. of bitstreams: 1 Ana Paula Lima do Cout1.pdf: 2447904 bytes, checksum: 7c9755ccd95ffbece7c6941079071845 (MD5) / Made available in DSpace on 2016-01-20T23:17:07Z (GMT). No. of bitstreams: 1 Ana Paula Lima do Cout1.pdf: 2447904 bytes, checksum: 7c9755ccd95ffbece7c6941079071845 (MD5) Previous issue date: 2014-09-30 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Funda??o de Amparo ? Pesquisa do Estado da Bahia - FAPEB / (Effect of edge in structure, diversity and phenology in seasonal tropical forest submontane) Forest fragmentation causes physical and biological changes with habitat loss and insularization of populations, and the edge effect the most obvious consequence of this process. Thus, this study aimed to investigate the effect of linear edge in a fragment of submontane seasonal forest in the Chapada Diamantina, Bahia, Brazil (12?28'31 "S and 41?23'14''W) in order to analyze the structure and composition vegetation, reproductive phenology and the vegetative phenology, classifying the forest as their leaf pattern, and the functional diversity. Were marked 30 plots (10 x 10 m) random and 15 at the forest edge (0 - 100m) and 15 inside (> 150m) in the power line high voltage. For structural studies were marked all individuals with diameter at breast height ?5 cm. The species were classified according to successional category and phytosociological parameters were calculated and diversity indices. The Shannon - Wiener index was compared by t test Hutcheson and the other parameters by ANOVA. From this study the species with the highest importance value and abundance for the other investigations were chosen. In the reproductive phenological study monthly observations were made over 26 months in 481 individuals (282 on the edge (61 species) and 199 inside (50 species) of forest), recording the presence and absence of flowering (and flower button) and fruiting (immature and mature fruit) for all life forms. It is estimated timing, frequency and duration of phenological events and the species were classified as the pollination and dispersal syndromes. Data were analyzed with G test, linear regression and circular statistics. In the study of functional diversity created a matrix of functional traits to the edge and interior including phenological, structural and reproductive aspects. Measurements of leaf traits (thickness, dry dough sheet per unit area, juiciness, density, leaf area ratio and leaf mass fraction), density and wood water saturation were carried out in the dry and wet seasons (September / 2012 and January / 2013) in 20 species. Regressions were made between phenophases and environmental variables (precipitation, temperature, relative humidity, photoperiod and heat stroke), circular statistics and comparisons of leaf traits and wood density between the dry and rainy season through the G test and ANOVA. The species ordination in relation to leaf and wood attributes was evaluated by Principal Component Analysis (PCA). The functional groups were defined by cluster analysis with distance Gower and calculated indexes Functional richness (FRic), Functional divergence (FDiv), Functional evenness (FEve), Functional dispersion (FDis). ANOVA and linear regression were used to evaluate the rates between areas. In vegetative phenological study followed up the budding and leaf fall 350 individual trees in the community (39 species). Increase the impact of straight edge on the floristic composition was checked, the diversity and abundance of species, while less interference was observed in the tree community structure, as phytosociological parameters and ratios between the guilds did not differ significantly between edge and interior fragment. The phenological analysis revealed that flowering and fruiting at the edge and interior were continued for long, low-intensity periods, asynchronous and assazonal being for most phenophases, with a significant difference in the individual to button number. Seasonality in flowering and fruiting were observed for bush and grass land in both areas and epiphytes to the edge. Similar proportions in the number of species for pollination and dispersal syndromes were found on the edge and inside, with a predominance of melittophilous and animal dispersed species. The vegetation was evergreen, with budding and continuous leaf fall, low intensity and low sync. The leaf bud was related to rainfall and sunshine and fall with precipitation and humidity. Significant variation between the dry and wet seasons were observed in the proportion of saturated water in the wood, leaf area ratio and leaf succulence. ACP showed greater variance for wood density (88.7%) and stored water (11.3%), gathering most species with standard perenif?lios phenological and episodic perenif?lios, other attributes showed no relevance to the phenological patterns. The main functional groups formed on the edge and inside were similar, defined based on the way of life, stratum and pollination and dispersal. Of co-occurring species (40 species), 22.5% belong to different functional groups due to different growth patterns. The functional diversity indices showed higher mean values for the edge, except that Fric was higher in the forest. These were not affected by the distance to the edge. Changes were observed inside in relation to species richness and Shannon - Wiener only for Fric. The implementation of linear infrastructure brings similar impacts to those coming from other types of edges in community structure. In other aspects analyzed the changes were subtle for the tree community, but the same was not true for shrubs, herbs and vines. The vegetation can be classified as seasonal submontane rainforest always green, with small annual variation in the physiognomy of the vegetation, and the perenif?lios and perenif?lios types episodic predominant both in number of species and in their abundance. The leaf traits showed no relevance to phenology, not being good descriptors for the seasonal evergreen forest. There is no significant difference in functional diversity, but the highest rate obtained inside for functional wealth reflects the biological loss caused by the installation on the edge of the linear edge. Appearance evidenced by the greater abundance of Eschweilera tetrapetala Mori inside, an endemic species of submontane forests of the region. This study contributes to future conservation work to note the interference the linear edge on the forest ecosystem, as well as to the classification of the Brazilian forests, to verify the occurrence of seasonal evergreen forests in the Caatinga. / (Efeito de borda na estrutura, diversidade e fenologia de floresta tropical estacional submontana) A fragmenta??o florestal causa mudan?as f?sicas e biol?gicas com perda de habitat e insulariza??o das popula??es, sendo oefeito de borda a consequ?ncia mais evidente desse processo.Assim,objetivou-se investigar o efeito da borda linear em um fragmento de floresta estacional submontana na Chapada Diamantina, Bahia,Brasil (12?28?31??S e 41?23?14??W) com o intuito de analisar a estruturae a composi??o da vegeta??o, a fenologia reprodutivae a fenologia vegetativa, classificando a floresta quanto ao seu padr?o foliar, e a diversidade funcional. Foram marcadas 30 parcelas (10 x 10 m) aleat?rias sendo 15 na borda da floresta (0 - 100m) e 15 no seu interior (>150m) em rela??o ? rede el?trica de alta tens?o. Para o estudo estrutural foram marcados todos os indiv?duos com di?metro ? altura do peito ?5 cm. As esp?cies foram classificadas quanto ? categoria sucessional e foram calculados os par?metros fitossociol?gicos e ?ndices de diversidade. O ?ndice de Shannon - Wienerfoi comparado pelo teste t de Hutcheson e os demais par?metros pela ANOVA. A partir desse estudo foram escolhidas as esp?cies com maior valor de import?ncia e abundancia para as demais investiga??es.No estudo fenol?gico reprodutivo foram realizadas observa??es mensais durante 26 meses a 481 indiv?duos (282 na borda (61 esp?cies) e 199 no interior (50 esp?cies) da floresta), registrando-se a presen?a e aus?ncia de flora??o (bot?o e flor) e frutifica??o (frutos imaturo e maturo) para todas as formas de vida. Estimou-se sincronia, frequ?ncia e dura??o dos eventos fenol?gicos e as esp?cies foram classificadas quanto ?s s?ndromes de poliniza??o e dispers?o. Os dados foram analisados com teste G, regress?o linear e estat?stica circular. No estudo da diversidade funcional criou-se uma matriz de tra?os funcionais para a borda e interior incluindo aspectos fenol?gicos, estruturais e reprodutivos.Mensura??es de atributos foliares (espessura, massa seca de folha por unidade de ?rea, sucul?ncia, densidade, raz?o de ?rea foliar e fra??o de massa foliar), densidade e ?gua de satura??o da madeira foram realizadas nas esta??es seca e chuvosa (setembro/2012 e janeiro/2013) em 20 esp?cies. Foram feitas regress?es entre as fenofases e as vari?veis ambientais (precipita??o, temperatura, umidade relativa, fotoper?odo e insola??o), estat?stica circular e compara??es dos atributos foliares e densidade de madeira entre a esta??o seca e chuvosa atrav?s do teste G e ANOVA. A ordena??o das esp?cies em rela??o aos atributos foliares e de madeira foi avaliada pela An?lise do Componente Principal (ACP). Os grupos funcionais foram definidos por Cluster analysis com dist?ncia de Gower e calculados os ?ndices Functional richness (FRic), Functional divergence (FDiv), Functional evenness (FEve), Functional dispersion (FDis). ANOVA e regress?o linear foram usadas para avaliar os ?ndices entre ?reas. No estudo fenol?gico vegetativo acompanhou-se o brotamento e queda foliar de 350 indiv?duos arb?reos na comunidade (39 esp?cies). Foi verificado um maior impacto da borda linear sobre a composi??o flor?stica,a diversidade e abund?ncia das esp?cies, enquanto menor interfer?ncia foi verificada na estrutura da comunidade arb?rea, uma vez que par?metros fitossociol?gicos e propor??es entre as categorias sucessionais n?o diferiram significativamente entre borda e interior do fragmento.As an?lises fenol?gicas revelaram que a flora??o e frutifica??o na borda e interior foram cont?nuas por per?odos longos e com baixa intensidade, sendo assincr?nico e assazonal para a maioria das fenofases, com diferen?a significativa no n?mero de indiv?duo para bot?o.Sazonalidade na flora??o e frutifica??o foi observada para arbusto e erva terrestre em ambas as ?reas e ep?fitas para a borda.Propor??es semelhantes no n?mero de esp?cies por s?ndromes de poliniza??o e dispers?o foram encontradas na borda e no interior, com predomin?ncia de esp?cies melit?filas e zooc?ricas.A vegeta??o foi perenif?lia, com brotamento e queda foliar cont?nuos, baixa intensidade e baixa sincronia. O brotamento foliar relacionou-se com precipita??o e insola??o e a queda com precipita??o e umidade. Varia??o significativa entre as esta??es seca e chuvosa foram observadas na propor??o de ?gua saturada na madeira, raz?o de ?rea foliar e sucul?ncia da folha. ACP revelou maior varian?a para densidade da madeira (88,7%) e ?gua armazenada (11,3%), agrupando a maioria das esp?cies com padr?o fenol?gico perenif?lios e perenif?lios epis?dicos, os demais atributos n?o apresentaram relev?ncia em rela??o aos padr?es fenol?gicos. Os principais grupos funcionais formados na borda e no interior foram semelhantes, definidos com base na forma de vida, estrato e s?ndrome de poliniza??o e dispers?o. Das esp?cies co-ocorrentes (40 esp?cies), 22,5% pertencem a grupos funcionais distintos devido a diferentes padr?es fenol?gicos. Os ?ndices de diversidade funcional apresentaram valores m?dios superiores para a borda, exceto FRic que foi superior no interior da floresta. Estes n?o foram alterados pela dist?ncia com a borda. Altera??es foram observadas no interior em rela??o ? riqueza de esp?cie e ao ?ndice de Shannon - Wiener apenas para FRic.A implementa??o de infraestruturas lineares traz impactos semelhantes ?queles advindos de outros tipos de bordas na estrutura da comunidade. Nos demais aspectos analisados as varia??es foram sutis para a comunidade arb?rea, mas o mesmo n?o ocorreuem rela??o a arbustos, ervas e trepadeiras. A vegeta??o p?de ser classificada como floresta tropical estacional submontana sempre verde, com pequena varia??o anual na fisionomia da vegeta??o, sendo os tipos perenif?lios e perenif?lios epis?dicos predominantes tanto em n?mero de esp?cies quanto na sua abund?ncia. Os atributos foliares n?o apresentaram relev?ncia em rela??o aos padr?es fenol?gicos, n?o sendo bons descritores para a floresta estacional sempre verde. N?o h? diferen?a significativa na diversidade funcional, mas o maior ?ndice obtido no interior para a riqueza funcional reflete a perda biol?gica ocasionada na borda pela instala??o da borda linear.Aspecto evidenciado pela maior abund?ncia deEschweilera tetrapetala Mori no interior, esp?cie end?mica das florestas submontanas da regi?o. O presente estudo p?de contribuir com futuros trabalhos de conserva??o por constatar a interfer?ncia da borda linear no ecossistema florestal, bem como com a classifica??o das florestas brasileiras, ao verificar a ocorr?ncia de florestas estacional sempre verde no Bioma Caatinga.

MSCAGR (Animal Science) / See the attached abstract below

No description available.