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Dinâmica da comunidade arbórea de um fragmento florestal urbano dominado por espécies exóticas / Tree community dynamics of an urban forest fragment dominated by exotic speciesSouza, Taísa Nascimento de 19 February 2018 (has links)
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Previous issue date: 2018-02-19 / A dominância de espécies exóticas é uma das principais características de florestas secundárias e dos chamados Novel Ecosystems. Apesar de estudos avaliarem os padrões destas comunidades em florestas tropicais úmidas, pouco ainda é conhecido sobre esses padrões em florestas tropicais. A espécie Pinus elliotti possui alto potencial invasor em florestas neotropicais, sendo encontrada em florestas secundárias da Zona da Mata Mineira. O objetivo deste estudo foi analisar a dinâmica (5 anos) da comunidade arbórea de uma floresta secundária urbana dominada por P. elliotti. As mudanças florísticas e estruturais foram analisadas a partir de comparações entre dois inventários realizados em parcelas permanentes (15 parcelas de 20 x 20 m alocadas aleatoriamente na floresta) nos anos de 2011 e 2016. Todos os indivíduos arbóreos com DAP ≥ 5 cm foram amostrados, mensurados, e calculados os parâmetros estruturais, fitossociológicos e diversidade de espécies. Foram calculadas as taxas de dinâmica (recrutamento, mortalidade, ganho e perda de área basal), sendo amostrados 943 indivíduos, 168 recrutas e 151 mortos. A comunidade apresentou forte dominância específica, com grande concentração dos valores de importância (VI) distribuídos nas sete primeiras espécies (Pinus elliottii; Miconia artemisiana; Mimosa artemisiana; Myrcia splendens, Pleroma mutabilis, Piptadenia gonoacantha e Miconia urophyla), que, juntas, somaram 52,2% do VI total. Entre as duas medições, a taxa de mortalidade, de 3,50%.ano-1, foi pouco inferior a de recrutamento, de 3,85%.ano-1. A taxa de ganho em área basal de 5,98%.ano-1, superou a de perda, de 2,90%.ano-1. Apesar da presença das espécies invasoras e da dinâmica acelerada, não foram observadas grandes alterações estruturais no fragmento, com tendência da comunidade de se manter floristicamente estável, a curto e médio prazo, em função da resistência das principais populações. / The dominance of exotic species is a major feature of secondary forests and socalled Novel Ecosystems. Although studies assess the patterns of these communities in tropical rainforests, little is known about these patterns in tropical forests. The species Pinus elliotti have high invasive potential in neotropical forests, and are found in secondary forests of the Zona da Mata at Minas Gerais State. The aim of this study was to analyze the dynamics (5 years) of the tree community of an urban secondary forest dominated by P. elliotti. Floristic and structural changes were analyzed from comparisons between two inventories in permanent plots (15 plots of 20 x 20 m randomly allocated in the forest) in the years 2011 and 2016. All tree individuals with DBH ≥ 5 cm were sampled, measured, and calculated the structural, phytosociological and species diversity parameters. Dynamic rates (recruitment, mortality, gain and loss of basal area) were calculated, being sampled 943 individuals, 168 recruits and 151 deaths. The community showed a strong specific dominance, with a high concentration of importance values (VI) distributed in the first seven species (Pinus elliottii; Miconia artemisiana; Mimosa artemisiana; Myrcia splendens; Pleroma mutabilis; Piptadenia gonoacantha; Miconia urophyla), which accounted for 52.2% of the total VI. Between the two measurements, the mortality rate of 3.50% .year-1 was slightly lower than that of recruitment of 3.85% .year-1. The rate of gain in basal area of 5.98% .year-1 exceeded that of loss of 2.90% .year-1. Despite the presence of invasive species and accelerated dynamics, there were no major structural changes in the fragment, believing that the community is able to remain floristically stable in the short and medium term, due to the resistance of the main populations.
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Avian assemblages of invasive Australian Acacia thickets in the Western CapeRogers, Andrew M. (Andrew Munro) 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Human-modified habitats form increasingly large components of landscapes, threatening
biodiversity and creating challenges for conservation. In some cases altered habitats form
entirely novel ecosystems that may support new combinations of species and species
abundances, and create habitat space in otherwise transformed landscapes. In the Western
Cape of South Africa, woody invasive species contribute to landscape-level habitat
transformation and form novel ecosystems. Invasive Australian Acacia species are especially
problematic in lowland areas where they create dense thickets and substantially transform
both biotic communities and abiotic processes. Despite the prominence of Acacia thickets
across the Western Cape, their ability to support native fauna is not well understood and the
objective of this study was to assess the significance of Acacia thickets as habitat for the
region’s avifauna. Birds were surveyed in Acacia thickets in the south-western Western Cape
in three seasons to examine species richness, abundance and functional abundance.
Furthermore, I examined the extent to which differences in patch-level vegetation structure
alter bird communities. Between survey sites and seasons, significant variation was observed
in assemblage richness, density, median body size and biomass. Variation in vegetation
density, stem density, mean vegetation height and total canopy cover best explained variation
in bird assemblages. Eighty species were estimated to utilize Acacia thickets and assemblages
had a mean density of 7.78 birds per ha. The most abundant feeding guilds were the mixed
feeders and insectivores. The median body size observed was 15.2 g and the body size
frequency distribution of all species in Acacia spanned a similar range compared to the body
size frequency distribution for the species list for the entire Western Cape. The mean biomass
of bird communities was 0.224 kg per ha. Using data on bird density and biomass, Acacia
thickets across the Fynbos Biome support and estimated average of over 21 million birds with
a combined biomass of over 600 thousand kg. This study found that Acacia thickets in the
Western Cape support a subset of the region’s birds with the most abundant species being
small mixed feeders, which are also frequently urban-adapted. Compared with other habitat
types, Acacia support bird assemblages with moderate species richness and density. This
study shows that Acacia thickets, as a novel habitat, provide a significant amount of habitat
space in a highly transformed landscape and highlights the need for comprehensive evaluation of altered habitats before assumptions are made about their ecological value. / AFRIKAANSE OPSOMMING: Getransformeerde habitatte maak vermeerderend groot deel uit van die omgewing, dit bedreig
biodiversiteit en skep groter uitdagings vir bewaring. In sommige gevalle vorm hierdie
getransformeerde habitatte geheel nuwe ekosisteme wat moontlik nuwe kombinasies van
spesies en spesie volopheid kan onderhou. Verder skep nuwe ekosisteme habitat spasie in
anders veranderde landskappe. In die Wes-Kaap van Suid-Afrika dra die Australiese Acacia
indringer spesies is veral problematies in laagliggende areas, aangesien dit digte ruigtes vorm,
asook beide die biotiese gemeenskappe en die abiotiese prosesse aansienlik transformeer. Ten
spyte daarvan dat daar volop Acacia ruigtes in die WesKaap is, word min verstaan van hul
vermoë om inheemse fauna te onderhou. Die hoofdoel van hierdie studie was om die belang
van Acacia ruigtes as habitat vir die area se voëllewe te bepaal. Voël-opnames in die suidwestelike
dele van die Wes-Kaap is gedoen in Acacia ruigtes oor drie seisoene, om
spesierykheid, volopheid en funksionele volopheid te ondersoek. Verder is die mate waartoe
verskille in die plotte van die plantegroei struktuur, die voëlgemeenskappe verander,
geondersoek. Daar was aansienlike variasie waargeneem in die spesiesamestelling rykheid,
voorkoms digtheid, mediaan liggaamsgrootte en biomassa van die voëls tussen die onderskeie
voëlopnaam plotte en die seisoene. Die variasie in plantegroei digtheid, stam digtheid,
mediaan plantegroeihoogte en totale kroonbedekking verduidelik hierdie variasie in
spesiesamestelling die beste. Tagtig voëlspesies Acacia ruigtes benut en die
populasiesamestelling het ‘n gemiddelde digtheid van 7,78 voëls per ha. Die mees algemene
voel-voeding-guldes was die gemengde-voedsel-vreters en insekvreters. Die median
liggaamsgrootte waargeneem was 15,2 g en die liggaamsgrootte frekwensieverspreiding van
alle spesies in Acacia ruigtes is ooreenkomstig met die liggaamsgrootte
frekwensieverspreiding vir die spesielys vir die hele Wes-Kaap. Die gemiddelde biomassa
van voel gemeenskappe was 0.224 kg per ha. Acacia ruigtes oor die fynbosbioom wat ‘n
geskatte gemiddelde van meer as 21 miljoen voels ondersteun, met ‘n gesamentlike biomassa
van meer as 600 duisend kg. Hierdie studie het bevind dat Acacia ruigtes in die Wes-Kaap ‘n
onderafdeling van die streek se voels ondersteun, met die mees algemene spesies as die klein
gemengde-voedsel-vreters, wat ook dikwels stedelik aangepas is. In vergelyking met ander
habitattipes ondersteun Acacia ruigtes voel samestellings met matige spesierykheid en
digtheid. Hierdie studie toon dat die Acacia ruigtes, as ‘n nuwe habitat, ‘n beduidende
hoeveelheid habitat ruimte in ‘n hoogs getransformeerde omgewing skep en beklemtoon die
behoefte aan ‘n omvattende evaluering van veranderde habitatte, voor aannames gemaak
word oor hul ekologiese waarde.
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A Coupled Human and Natural Systems Approach to Understanding an Invasive Frog, Eleutherodactylus Coqui, in HawaiiKalnicky, Emily A. 01 May 2012 (has links)
Human activities worldwide have altered nature in ways that create new combinations of species and environmental processes. To understand so-called "novel ecosystems" it is important to consider both the natural and the societal factors that shape them, and how those factors are interconnected or "coupled." We used such an approach to explore options for managing a non-native invasive frog, the coqui, which has become established on the island of Hawaii and threatens to spread to other parts of the state.
The nighttime calls of the coqui create a nuisance for property owners when populations become dense enough, as often occurs in Hawaii where the frogs have no natural enemies. Humans have tried various ways to eliminate coqui on the island of Hawaii with little success. Therefore we studied how property owners cope with their presence, both through management practices and psychological coping strategies. We also examined results of those efforts. People whose properties had more frogs were more likely to take action to reduce their numbers, but also attitudes toward the coqui were less negative when people had grown used to having to share their properties with the frogs. For those who cannot cope psychologically, we found it would be possible to manage properties to reduce densities but only when leaf litter and low shrubs were completely removed from near a home. Information campaigns about managing coqui should be different when targeting people that already host frogs and those that do not.
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A century of landscape-level changes in the Bow watershed, Alberta, Canada, and implications for flood managementTaggart-Hodge, Tanya 09 December 2016 (has links)
This study used a comparison of one hundred and forty-eight historical (1888-1913) and current (2008-2014) oblique photographs from thirty-two stations to identify land cover changes that have occurred in portions of the Bow and Elbow valleys as well as surrounding Kananaskis Country region. Implications of these changes for flooding and flood management were explored. Forest cover was found to have drastically increased over the past century, particularly in the Bow valley, as did areas of direct human development. In the same time period, grasslands increased in the Elbow valley but decreased in the Bow, while regenerating areas decreased uniformly throughout both valleys. An analysis of pre (2008)-and-post (2014) flood conditions demonstrated no change in coniferous forest cover in both valleys over the 6-year period, but uncovered a decline of 20% in the Elbow and 3% in the Bow in the broadleaf/mixedwood category. The Elbow’s channel zone was larger in 2014 compared to 2008, whereas the extent of the Bow’s channel zone remained constant. However, both the Bow and Elbow’s bare exposed bars increased substantially, most likely as a result of the 2013 flood. The major source of water flows that contributed to the 2013 flood event originated in high elevation rock and scree areas, which, unlike floodplains, are elements of the watershed that cannot be manipulated over time. It is now recognized that forest cover should act as a buffer to floods. Nevertheless, the 2013 flood event occurred despite the massive buffering effect of a huge increase in older forest stands across the study area. The final discussion includes recommendations for improving flood management in the area. / Graduate / 0329, 0768, 0478 / tanya.taggarthodge@gmail.com
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Understanding the mechanisms behind invasion to improve the efficacy of control strategiesJennifer Firn Unknown Date (has links)
Abstract The negative impact of invasive plant species on biodiversity and ecosystem functions, such as productivity and nutrient cycling has been deemed a global epidemic. To address this worldwide concern, information is needed on how the invasion process happens and how to control an existing invasion. The main aim of the research presented in this thesis was to develop a better understanding of the interacting role different mechanisms play in facilitating invasion and then link this understanding to the design of more effective control strategies. This aim is significant because traditional weed control strategies are not working. The estimated cost of controlling weeds in Australia is $1.4 billion per year in agricultural landscapes. Despite this substantial investment, invasive weed species are estimated to continue to cost the agricultural industry $2.2 billion per year in loss of yield. Current control strategies tend to focus on killing or removing an invasive plant species directly with the application of herbicides and/or mechanical removal. These strategies have proven ineffectual because the plant communities that assemble after management often remain dominated by the same invader or another. In this thesis, I use a combination of empirical and modelling techniques to investigate how disturbance regimes and competitive interactions between invasive plants and native plants can be manipulated to improve the efficacy of restoration efforts. To do this, I use the model scenario of the invasion of Eragrostis curvula (African lovegrass), an invasive grass species introduced into Australia in the early 1900s from South Africa. This species has now spread into every Australian state and territory (chapter 2). I specifically focus on two mechanisms: (1) disturbance, i.e. cattle grazing, and (2) competitive interactions. In chapter 3, I examine connections between dominance and competitive differences among African lovegrass and several functionally similar native grass species in a pasture community. To test the displacement hypothesis, I used a glasshouse competition trial to investigate interactions between African lovegrass and two non-persisting native grass species (Themeda australis and Bothriochloa decipiens) with manipulations of resources, neighbour density, and establishment order. To test the partitioning hypothesis, I compared in situ water use patterns among African lovegrass and two coexisting native grass species (Aristida calycina and Aristida personata) based on the assumption that water is the most limiting resource in this system. The key finding of this chapter is that competition can have important, but contingent, impacts on dominance. Competitive differences appear to partially contribute to abundance patterns after establishment, but may be relatively unimportant during the establishment phase where disturbance appears more critical. In chapter 4, I provide evidence that the identification of mechanisms that led to an invasion, while crucial for the development of effective preventative measures and understanding the invasion process, may not be necessary for the design of more effective control strategies. To examine the effects of different control strategies on African lovegrass and the resultant community, I established a large factorial field-trial with a split-plot design. I manipulated grazing, soil nutrient levels and the presence of the invader. The most common control strategy (removing the causal disturbance and killing the invasive grass), based implicitly on traditional equilibrium models, was not an effective option for restoring a desirable native community. Instead, this strategy led to the dominance of a secondary invader. The most effective control strategy was based on alternative stable states models and involved maintaining grazing, and increasing the palatability of the invader with fertilizers. The key finding of this chapter is that novel approaches for control, which consider the dynamics of the invader-dominated system, are needed. In chapter 5, I investigate the benefits of explicitly incorporating actions that manipulate disturbance (natural or imposed) into control efforts. To do this, I first developed a process model that described the dynamics of an invader whose establishment is preferentially favoured by disturbance. I then couched this model in a decision theory framework, a stochastic dynamic program, and applied a case-study of another invasive plant species, Mimosa pigra (a perennial legume shrub and pan-tropical weed). The key finding of this chapter is that strategies should not only focus on existing invader-dominated sites, but should also protect sites occupied by native species from disturbances that facilitate invasion. The research discussed in this thesis makes three key contributions to a better understanding of the invasion process and the design of more effective control strategies: 1) the search for one key mechanism is not sufficient because multiple mechanisms can interact or shift in importance to facilitate different stages of invasion, 2) a novel approach is needed to restore a more desirable native community because the dynamics of the invader-dominated system can differ from the historical native community, and 3) control efforts should be broadened in focus to include protection of the integrity of native communities from disturbances that facilitate invasion.
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Diversidade de espécies arbóreas e sua relação com o histórico de perturbação antrópica em uma paisagem urbana da Floresta Atlântica / Tree species diversity and its relation with the history of anthropic disturbance in an urban landscape of the Atlantic ForestFonseca, Cassiano Ribeiro da 09 March 2017 (has links)
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Previous issue date: 2017-03-09 / O processo de urbanização é um dos maiores agentes de transformação da sociedade, com reflexos diretos na biodiversidade global. A maior expansão global da urbanização em ambientes naturais prevista até 2030 ocorrerá com a conversão de ambientes naturais em áreas urbanas na América do Sul. As alterações criadas pelo ambiente urbano fragmentam florestas, impedem sua conectividade, criam mudanças das condições microclimáticas, modificam o equilíbrio físico e biológico, deixando impactos diretos na estrutura, riqueza e também na diversidade dos ecossistemas florestais. Considerando a importância das florestas urbanas para a manutenção da biodiversidade, este estudo analisou como os padrões de diversidade alfa e beta variam nas comunidades de florestas urbanas, fazendo uma relação com seu histórico de perturbação. O estudo foi realizado na mesorregião da Zona da Mata Mineira na microrregião de Juiz de Fora, nas cidades de Juiz de Fora, Lima Duarte, Rio Preto e Santos Dumont. Foram amostrados todos os indivíduos arbóreos vivos (DAP ≥ 5 cm) em 12 trechos de florestas, sendo alocadas aleatoriamente 10 parcelas de 20 x 20 m, totalizando 120 parcelas, com área total amostrada de 4,8 ha. Os trechos foram classificados de acordo com os diferentes níveis de perturbação, históricos de impactos antrópicos, tipos de distúrbios e estrutura atual; e distribuídos em quatro ambientes florestais com características compartilhadas (controle, relicto, agricultura abandonada e terraplanagem). A partir dos resultados foi possível perceber um claro padrão de agrupamento entre os quatro ambientes florestais, os valores de riqueza, índices de diversidade e equabilidade, variaram de acordo com o grau de impacto sofrido, obtendo os maiores valores fragmentos mais preservados, e menores aqueles que sofreram os maiores impactos antrópicos. A análise da diversidade beta demonstrou baixo número de espécies compartilhadas, evidenciando grande heterogeneidade florística nos ambientes florestais urbanos. As análises de agrupamentos demonstraram que a estrutura dos ambientes florestais são o reflexo dos tipos e intensidades dos distúrbios causados pelo ambiente urbano, representadas na forma de grupos com grande autocorrelação. Apesar das grandes alterações construídas pelo ambiente urbano antrópico, ainda assim os fragmentos urbanos abrigam importante diversidade alfa e beta da flora arbórea regional. O conhecimento sobre a biodiversidade das florestas tropicais urbanas é fundamental para subsidiar ações de proteção, conservação e restauração da biota regional. / The urbanization process is one of the major agents in society transformation, with direct reflex on global biodiversity. The largest urbanization global expansion in natural environments, expected until 2030, will occur from the conversion of natural environments to urban areas in South America. The changes generated by urban settings fragment forests, hinder their connectivity, alter microclimate conditions and modify physical and biological balance, directly impacting on the structure, wealth and diversity of the forest ecosystem. Considering the importance of urban forests to the maintenance of biodiversity, this paper aims to analyze how alfa and beta diversity patterns vary in urban forest communities, relating to its disturbance history. The study took place in the mesoregion of Zona da Mata Mineira, in the microregion of Juiz de Fora, in the cities of Juiz de Fora, Lima Duarte, Rio Preto and Santos Dumont. All live arboreal individuals (DBH ≥ 5 cm) in twelve forest fragments were sampled, being 10 plots of 20 x 20m randomly allocated, totaling 120 plots. The fragments were classified according to the different levels of disturbance, history of human impact, types of disturbance and current structure; they were assorted in four forest settings with shared features (control, relict, abandoned agriculture and earthwork). From the results, it was possible to notice a clear pattern of grouping among the four forest settings; the values of wealth and diversity and equitability rates varied according to the impact endured, obtaining higher values in the most preserved fragments and lower in those which suffered with major human influence. The beta diversity analysis showed a low number of shared species, revealing great floristic heterogeneity in urban forest environments. The grouping analysis showed that forest environments reflect great changes caused by urban settings, depicted by groups with great autocorrelation. Regardless of alterations built by human urban settings, these urban fragments hold important alfa and beta diversity from the regional arboreal flora. Knowledge of urban rainforests biodiversity is essential to subsidize protection measures, preservation and recovery of regional biota.
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Diversidade de espécies arbóreas e sua relação com o histórico de perturbação antrópica em uma paisagem urbana da Floresta Atlântica / Tree species diversity and its relation with the history of anthropic disturbance in an urban landscape of the Atlantic ForestFonseca, Cassiano Ribeiro da 09 March 2017 (has links)
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Previous issue date: 2017-03-09 / O processo de urbanização é um dos maiores agentes de transformação da sociedade, com reflexos diretos na biodiversidade global. A maior expansão global da urbanização em ambientes naturais prevista até 2030 ocorrerá com a conversão de ambientes naturais em áreas urbanas na América do Sul. As alterações criadas pelo ambiente urbano fragmentam florestas, impedem sua conectividade, criam mudanças das condições microclimáticas, modificam o equilíbrio físico e biológico, deixando impactos diretos na estrutura, riqueza e também na diversidade dos ecossistemas florestais. Considerando a importância das florestas urbanas para a manutenção da biodiversidade, este estudo analisou como os padrões de diversidade alfa e beta variam nas comunidades de florestas urbanas, fazendo uma relação com seu histórico de perturbação. O estudo foi realizado na mesorregião da Zona da Mata Mineira na microrregião de Juiz de Fora, nas cidades de Juiz de Fora, Lima Duarte, Rio Preto e Santos Dumont. Foram amostrados todos os indivíduos arbóreos vivos (DAP ≥ 5 cm) em 12 trechos de florestas, sendo alocadas aleatoriamente 10 parcelas de 20 x 20 m, totalizando 120 parcelas, com área total amostrada de 4,8 ha. Os trechos foram classificados de acordo com os diferentes níveis de perturbação, históricos de impactos antrópicos, tipos de distúrbios e estrutura atual; e distribuídos em quatro ambientes florestais com características compartilhadas (controle, relicto, agricultura abandonada e terraplanagem). A partir dos resultados foi possível perceber um claro padrão de agrupamento entre os quatro ambientes florestais, os valores de riqueza, índices de diversidade e equabilidade, variaram de acordo com o grau de impacto sofrido, obtendo os maiores valores fragmentos mais preservados, e menores aqueles que sofreram os maiores impactos antrópicos. A análise da diversidade beta demonstrou baixo número de espécies compartilhadas, evidenciando grande heterogeneidade florística nos ambientes florestais urbanos. As análises de agrupamentos demonstraram que a estrutura dos ambientes florestais são o reflexo dos tipos e intensidades dos distúrbios causados pelo ambiente urbano, representadas na forma de grupos com grande autocorrelação. Apesar das grandes alterações construídas pelo ambiente urbano antrópico, ainda assim os fragmentos urbanos abrigam importante diversidade alfa e beta da flora arbórea regional. O conhecimento sobre a
vi
biodiversidade das florestas tropicais urbanas é fundamental para subsidiar ações de proteção, conservação e restauração da biota regional. / The urbanization process is one of the major agents in society transformation, with direct reflex on global biodiversity. The largest urbanization global expansion in natural environments, expected until 2030, will occur from the conversion of natural environments to urban areas in South America. The changes generated by urban settings fragment forests, hinder their connectivity, alter microclimate conditions and modify physical and biological balance, directly impacting on the structure, wealth and diversity of the forest ecosystem. Considering the importance of urban forests to the maintenance of biodiversity, this paper aims to analyze how alfa and beta diversity patterns vary in urban forest communities, relating to its disturbance history. The study took place in the mesoregion of Zona da Mata Mineira, in the microregion of Juiz de Fora, in the cities of Juiz de Fora, Lima Duarte, Rio Preto and Santos Dumont. All live arboreal individuals (DBH ≥ 5 cm) in twelve forest fragments were sampled, being 10 plots of 20 x 20m randomly allocated, totaling 120 plots. The fragments were classified according to the different levels of disturbance, history of human impact, types of disturbance and current structure; they were assorted in four forest settings with shared features (control, relict, abandoned agriculture and earthwork). From the results, it was possible to notice a clear pattern of grouping among the four forest settings; the values of wealth and diversity and equitability rates varied according to the impact endured, obtaining higher values in the most preserved fragments and lower in those which suffered with major human influence. The beta diversity analysis showed a low number of shared species, revealing great floristic heterogeneity in urban forest environments. The grouping analysis showed that forest environments reflect great changes caused by urban settings, depicted by groups with great autocorrelation. Regardless of alterations built by human urban settings, these urban fragments hold important alfa and beta diversity from the regional arboreal flora. Knowledge of urban rainforests biodiversity is essential to subsidize protection measures, preservation and recovery of regional biota.
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Urban ecology in Christchurch: a reconciliation approach to enhancing native biodiversity on urban greyfieldsGreenep, H. K. January 2009 (has links)
Traditionally New Zealand ecological research has focused on nature outside of cities, however, as with global trends, there is now more interest being given to the ecological functioning of cities and the potential they may hold for protecting native biodiversity. Traditionally, efforts to maintain biodiversity in urban areas have been restricted to remnants of native vegetation and restoration activities. Little attention has been given to how native biodiversity could be woven into the urban fabric in an ecologically meaningful way. One option, that is receiving much attention overseas, is to recruit underutilised urban spaces such as wasteland. A subset of urban wasteland, abandoned industrial areas usually awaiting development and other areas such as the railway buffer, are referred to here as greyfield. These are ephemeral sites that may sit between uses for as little as a few months to many years. Overseas, particularly in European countries, these have been recognised as important habitat for both native and introduced plant species. In New Zealand cities these support primarily introduced plants and their contribution to native biodiversity has been unknown. This thesis took an interdisciplinary approach to the question of whether urban greyfields might have potential value as biodiversity protection and conservation opportunity. Ecological methods were combined with an assessment of the planning framework to answer this question. iii Greyfields in Christchurch, New Zealand were surveyed to determine their current contribution to native biodiversity and whether they may act as urban analogues of natural habitats. Overseas research has shown that urban features such as pavements, walls and rooftops offer habitats analogous to cliffs and rocky habitats. Cities are therefore increasing the habitat exploitable by species whose natural habitats are geographically restricted. The Christchurch greyfields were assessed for their potential to act as analogues of four habitat types that have been categorised as historically rare in New Zealand: braided riverbeds, shingle beaches, rock outcrops and limestone outcrops. The findings suggest that urban greyfields, if managed appropriately, have the potential to support a wider range of native species Planning documents and biodiversity strategies written for Christchurch were assessed to see how well they facilitated non-traditional biodiversity enhancement initiatives, specifically the greyfield network for native biodiversity. A major finding here was a lack of information on how to enhance biodiversity where little of the natural features of the landscape were left and that this was creating a barrier to adopting more integrative approaches to enhancing native biodiversity. Finally, a plan to create a greyfield network for native biodiversity is proposed and suggestions are made as to minor changes to the planning framework that would more easily facilitate the uptake of novel biodiversity enhancement initiatives in the City.
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Population dynamics of hybrid ecosystems: Implications for marginal ecosystem conservation and managementNichter, Ashlee N. 29 November 2017 (has links)
No description available.
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Biotopmanagement in Festungsanlagen – Trittsteine und Habitate für die BiotopvernetzungJunghans, Veikko 08 April 2021 (has links)
Durch vegetationsökologische Feldstudien wurde das Biotop- und Arteninventar verschiedener Festungsanlagen des 19. Jahrhunderts in Deutschland, Polen und Litauen untersucht. Ein Ziel der Untersuchung war die Bewertung der Standorte für eine Einbindung in den FFH Biotop-Verbund, ergänzt durch Auswertungen historischer Luftbilder sowie Sentinel2-Fernerkundungsdaten.
Die Festungsanlagen neigten in den letzten Jahrzehnten zu einer Wiederbewaldung durch ausbleibende Nutzung und Pflege der Offenlandbereiche. Innerhalb weniger Jahrzehnte sind vor Ort vor allem stadtwaldähnliche Standorte entstanden. Eine Entwicklung hin zu standorttypischen Ausprägung einer HPNV oder anderer Gesellschaften, die als Biotoptypen nach Anhang I FFH-RL ausweisbar wären, ist an den untersuchten Standorten nicht beobachtet worden. Hohe Biotopqualitäten in Offenland-Standorten sowie anderen Biotoptypen sind nicht beobachtet worden.
Festungen und deren Biotope sind als Novel Ecosystems ausweisbar und wären nur als solche in das Biotopverbundsystem integrierbar. Satellitenbasierte Auswertungen bilden die Kleinräumigkeit der örtlichen Biotopstrukturen –und deren Vielfalt nur bedingt ab. Fehlende Pflege und Nutzung von Festungen sowie aufkommende Waldbestände verursachen eine sukzessive Degradation und Schädigung der Bausubstanz.
Eine naturschutzfachliche Begründung für das grundsätzliche Ausbleiben von Sanierung und Bausubstanzerhalt existiert nicht, auch wenn diese Standorte oftmals Habitate für Arten des Anhang IV der FFH-RL aufweisen. Im Gegensatz, die Pflege und der Erhalt des Kulturerbes „Festungsanlagen“ wird von der europäischen Naturschutz- und vor allem Kulturagenda sogar gefordert, da diese neben noch unspezifiziertem Natur- und Erholungswert auch einen intrinsischen gesamteuropäischen Kulturwert haben. Das muss bei der lokalen Raum- und Naturschutzfachplanung sowie in der regionalen Landespflege berücksichtigt werden. / The biotope and species inventory of various fortifications of the 19th century in Germany, Poland and Lithuania was examined through vegetation-ecological field studies. One aim of the study was to evaluate the locations for integration into the FFH biotope network, supplemented by evaluations of historical aerial photos and Sentinel2 remote sensing data.
Investigated fortifications tended to reforest in recent decades due to the lack of use and maintenance of the open land areas. Within a few decades, urban forest-like sites have developed here at the investigated sites. A development towards site-typical expressions of PNV or other communities, which could be designated as FFH biotopes according to Annex I of the Habitats Directive, has not been observed. High biotope qualities in open land biotopes and other types were not observed
Fortresses and their biotopes can be designated as Novel Ecosystems and should only be integrated as such into the biotope network. Satellite based evaluations only provide a limited picture of the small-scale nature and diversity of local biotope structures. The lack of maintenance and use of fortresses as well as emerging forest stands cause successive degradation and damage to the building fabric.
There is no nature conservation justification for the fundamental lack of remediation and preservation of building fabric, even though these sites often have habitats for species listed in Annex IV of the Habitats Directive. In contrast, the care and preservation of the cultural heritage "fortifications" is even demanded by the European nature conservation and cultural agenda, as they have an intrinsic pan-European cultural value in addition to still unspecified nature and recreational value. This is even reflected by the aim of the Habitats Directive. This must be taken into account in local spatial and nature conservation planning and in regional land management.
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