This thesis investigates the influence of nonrandom species loss on the structure and functioning of trophic floodplain lagoons. Two experiments were conducted based on different realistic scenarios of biodiversity loss using multitrophic fish assemblages derived from long-term survey data. Loss of fish diversity influenced overall ecosystem multifunctionality of these lagoons through complex multitrophic interactions throughout the aquatic food web. These results indicate that biodiversity loss from diverse multitrophic ecosystems can influence ecosystem structure and function and likely deviate from simplified food chain dynamics or patterns that emerged from single trophic level studies.

Loss of biodiversity is one of the most severe threats to the ecosystems of the world. The major causes behind the high population and species extinction rates are anthropogenic activities such as overharvesting of natural populations, pollution, climate change and destruction and fragmentation of natural habitats. There is an urgent need of understanding how these species losses affect the ecological structure and functioning of our ecosystems. Ecological communities exist in a landscape but the spatial aspects of community dynamics have until recently to large extent been ignored. However, the community’s response to species losses is likely to depend on both the structure of the local community as well as its interactions with surrounding communities. Also the characteristics of the species going extinct do affect how the community can cope with species loss. The overall goal of the present work has been to investigate how both local and regional processes affect ecosystem stability, in the context of preserved biodiversity and maintained ecosystem functioning. The focus is particularly on how these processes effects ecosystem’s response to species loss. To accomplish this goal I have formulated and analyzed mathematical models of ecological communities. We start by analyzing the local processes (Paper I and II) and continue by adding the regional processes (Paper III, IV and V). In Paper I we analyze dynamical models of ecological communities of different complexity (connectance) to investigate how the structure of the communities affects their resistance to species loss. We also investigate how the resistance is affected by the characteristics, like trophic level and connectivity, of the initially lost species. We find that complex communities are more resistant to species loss than simple communities. The loss of species at low trophic levels and/or with high connectivity (many links to other species) triggers, on average, the highest number of secondary extinctions. We also investigate the structure of the post-extinction community. Moreover, we compare our dynamical analysis with results from topological analysis to evaluate the importance of incorporating dynamics when assessing the risk and extent of cascading extinctions. The characteristics of a species, like its trophic position and connectivity (number of ingoing and outgoing trophic links) will affect the consequences of its loss as well as its own vulnerability to secondary extinction. In Paper II we characterize the species according to their trophic/ecological uniqueness, a new measure of species characteristic we develop in this paper. A species that has no prey or predators in common with any other species in the community will have a high tropic uniqueness. Here we examine the effect of secondary extinctions on an ecological community’s trophic diversity, the range of different trophic roles played by the species in a community. We find that secondary extinctions cause loss of trophic diversity greater than expected from chance. This occurs because more tropically unique species are more vulnerable to secondary extinctions. In Paper III, IV and V we expand the analysis to also include the spatial dimension. Paper III is a book chapter discussing spatial aspects of food webs. In Paper IV we analyze how metacommunities (a set of local communities in the landscape connected by species dispersal) respond to species loss and how this response is affected by the structure of the local communities and the number of patches in the metacommunity. We find that the inclusion of space reduces the risk of global and local extinctions and that lowly connected communities are more sensitive to species loss. In Paper V we investigate how the trophic structure of the local communities, the spatial structure of the landscape and the dispersal patterns of species affect the risk of local extinctions in the metacommunity. We find that the pattern of dispersal can have large effects on local diversity. Dispersal rate as well as dispersal distance are important: low dispersal rates and localized dispersal decrease the risk of local and global extinctions while high dispersal rates and global dispersal increase the risk. We also show that the structure of the local communities plays a significant role for the effects of dispersal on the dynamics of the metacommunity. The species that are most affected by the introduction of the spatial dimension are the top predators.

Ash dieback is a severe disease of ash trees (Fraxinus spp.), caused by the invasive fungus Hymenoscyphus fraxineus. In its native East Asia, H. fraxineus is a harmless endophyte, but since its accidental import into Europe in the early 1990s it has infected over 90% of ash trees in some areas, with long-term mortality sometimes exceeding 90%. The disease was discovered in Great Britain in 2012, and has since spread rapidly. This thesis investigates some of the possible impacts on biodiversity, ecosystem functioning, and society, and in doing so identifies ways to alleviate some impacts. Britain has only 13% tree cover (among the lowest in Europe), so may be particularly vulnerable to ash loss. Better understanding of the effects and how to minimise them is critical to deliver an evidence-based response. First, we investigated impacts in woodlands by experimentally killing woodland ash trees by ring-barking. We found no short-term effect of ash loss on ground flora or earthworm communities, or on the regeneration or growth of other woody species. Observational evidence suggested that remaining canopy trees rapidly filled gaps left by ash, perhaps contributing to stability. Our woodlands appeared to be remarkably resilient to ash loss, although there may be long-term effects or impacts on other species that this experiment failed to observe. To investigate broader-scale impacts, we required high-quality abundance maps for ash and other trees across Britain. Using species distribution modelling and random forest regression, we developed a protocol to produce abundance maps from readily available data. We tested the predictive power of the resulting maps using cross validation. Our maps are the best available for abundance of British tree species, and will be useful across a wide range of disciplines. We then used them to model ecosystem vulnerability to ash loss, based on the abundance of ash and other tree species, and their ecological trait similarity. We identified areas at risk of the largest impacts, and produced guidance for positive management actions to minimise ecological change. Lastly, we investigated the financial impacts of ash dieback, estimating the total cost to Britain at £9.2 billion. This figure is many times larger than the value of lost trade if biosecurity were improved to prevent future invasions, questioning the validity of financial arguments against biosecurity. We also found that loss of ecosystem services accounted for less than a third of the total cost, suggesting that ecosystem service assessments may miss a large proportion of the true cost of biodiversity loss. Overall, we found that some impacts may be less than expected, such as local effects on woodland ground flora, and others, such as the economic cost, may be much larger than expected. However, the resilience of ecosystems to a major shock such as loss of a common species, and actions to mitigate the impacts, depend on having a diversity of other trees present. The ash dieback outbreak highlights the importance of preventing other severe pests and diseases of trees from being introduced; something that has been increasing exponentially, largely due to international trade in trees. This thesis provides further firm evidence that there is an ecological and social imperative to halt this trend.

<p>The work in this thesis deals with effects of changed species richness on process rates among stream-living macroinvertebrates. Global biodiversity is decreasing rapidly and it is poorly known what the consequences of this loss may be for ecosystems and the services they provide. Hence, it is important to investigate the potential effects of losing species. In streams, deforestation, introduction of non-native species, pollution and channelization are examples of events that may affect species richness negatively. In this thesis emphasis is on changes in species richness within functional feeding groups (FFGs) of stream-living macroinvertebrates. The FFGs used were shredding detritivores, grazers, filter feeders and predators - all of which uphold important ecological processes in streams. Along with an observational field study, species richness was manipulated in laboratory and field experiments to investigate the effects of changed species richness on process rates and thus ecosystem functioning.</p><p>The results show that effects of changed species richness on process rates may be dramatic. Among the shredding detritivores there were negative effects on leaf mass loss, regardless whether fixed, random or predicted sequences of species loss was investigated. These effects could be attributed to either species richness per se or species composition. However, among the other FFGs the relationship between species richness and process rates was less consistent. In filter feeders, there was no or a negative effect of decreasing species richness while both grazers and predators showed positive effects of species loss.</p><p>The results also show that the most important interactions between species in an experiment, thus potentially in a natural community, are likely to determine what the effect of species loss on process rates will be. Facilitation and niche differentiation lead to reduced process rates if species are lost, while mechanisms, such as interspecific resource or interference competition, produce the opposite effect. Furthermore, in systems with a diminishing resource, the first two mechanisms may become more important over time enhancing the effect of species loss in the long term.</p><p>In conclusion, effects of species loss may be dramatically negative or positive even if lost species are classified as redundant. The effect in the short term most likely depends on which species are lost, on the original species composition and on the underlying mechanisms. Questions remaining to be answered are how important the observed effects are in more complex systems and if they are persistent over time? Future studies will tell. </p>

The work in this thesis deals with effects of changed species richness on process rates among stream-living macroinvertebrates. Global biodiversity is decreasing rapidly and it is poorly known what the consequences of this loss may be for ecosystems and the services they provide. Hence, it is important to investigate the potential effects of losing species. In streams, deforestation, introduction of non-native species, pollution and channelization are examples of events that may affect species richness negatively. In this thesis emphasis is on changes in species richness within functional feeding groups (FFGs) of stream-living macroinvertebrates. The FFGs used were shredding detritivores, grazers, filter feeders and predators - all of which uphold important ecological processes in streams. Along with an observational field study, species richness was manipulated in laboratory and field experiments to investigate the effects of changed species richness on process rates and thus ecosystem functioning. The results show that effects of changed species richness on process rates may be dramatic. Among the shredding detritivores there were negative effects on leaf mass loss, regardless whether fixed, random or predicted sequences of species loss was investigated. These effects could be attributed to either species richness per se or species composition. However, among the other FFGs the relationship between species richness and process rates was less consistent. In filter feeders, there was no or a negative effect of decreasing species richness while both grazers and predators showed positive effects of species loss. The results also show that the most important interactions between species in an experiment, thus potentially in a natural community, are likely to determine what the effect of species loss on process rates will be. Facilitation and niche differentiation lead to reduced process rates if species are lost, while mechanisms, such as interspecific resource or interference competition, produce the opposite effect. Furthermore, in systems with a diminishing resource, the first two mechanisms may become more important over time enhancing the effect of species loss in the long term. In conclusion, effects of species loss may be dramatically negative or positive even if lost species are classified as redundant. The effect in the short term most likely depends on which species are lost, on the original species composition and on the underlying mechanisms. Questions remaining to be answered are how important the observed effects are in more complex systems and if they are persistent over time? Future studies will tell.

Sustainability, a multidimensional concept, consist of various environmental, social, and economic factors. Its fundamental principle is to fulfill the needs of the present without compromising the ability of future generations to meet their own needs. One popular approach to measure sustainability is the Environmental, Social, and Governance (ESG) measurement. However, a global standardized ESG rating system is currently lacking, leading to variations in scores and methodologies used by different agencies to evaluate a companies' ESG performance. Recognizing the need for a standardized approach, the Sustainable Development Goals (SDGs) has emerged as a framework for evaluating sustainability. By adopting the SDGs as a standardized framework, investors, companies, and financial institutions can align their effort and process towards a sustainable future.  Although previous research has explored the relationship between ESG and financial performances, little research has been conducted on the standardized framework of SDGs and its relationship with biodiversity impact. This while it has been proven that biodiversity is the primary driver of sustainability. The objective of the study is to fill the research gap by examining the relationship between SDG commitments and their impact on biodiversity. To achieve this, eight equity funds with varying commitments to SDGs were selected as a sample. The sample comprises 396 companies allocated to 42 countries and 87 industries, with data collected of the year 2022. To align with biodiversity data availability, the time frame was adjusted to match the biodiversity data from the year of 2011.  The study focuses on assessing the annual species loss as an indicator of biodiversity impact for four different levels of SDG commitments. The primary findings indicates that there is no significant relationship between the amount of SDG commitments and the annual species loss. Furthermore, a weak relationship was observed between the cost of goods sold (excluding depreciation) and annual species loss. The secondary findings suggests that the factors of country of operation and industries contributes to biodiversity impact, this while it revealed a high variation of the effecting ecosystem. In conclusion, this study sheds light on the relationship between SDG commitments and biodiversity impact, providing insights into the complex dynamics between sustainability efforts and their environmental consequences.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-08-03T11:52:14Z No. of bitstreams: 1 2011 - Gabriela Bueno B. Silva.pdf: 16499028 bytes, checksum: f77bf195f420f4227c29b60a75895d0d (MD5) / Made available in DSpace on 2016-08-03T11:52:14Z (GMT). No. of bitstreams: 1 2011 - Gabriela Bueno B. Silva.pdf: 16499028 bytes, checksum: f77bf195f420f4227c29b60a75895d0d (MD5) Previous issue date: 2011-04-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES, Brasil. / BITTENCOURT-SILVA, Gabriela Bueno. Insular Anuran (Amphibia) Communities of the Southeast Coast of Brazil: Taxonomic Composition and Relationship to the History of the Islands. 2011. 72p. Dissertation (Master of Science in Animal Biology). Instituto de Biologia, Departamento de Biologia Animal, Universidade Federal Rural do Rio de Janeiro, Serop?dica, RJ, 2011. A data set containing a list of the known species of frogs that occur near shore and on eight islands of the south coast of the State of Rio de Janeiro and north of the State of S?o Paulo was produced. For that, I compiled data from the literature and conducted inventories of a few of the islands. This list included 67 anuran species belonging to 11 families for eight islands and 117 species and 14 families for two localities on the mainland. The pattern of richness between islands was analyzed in respect to the island area and the composition of habitats used by the anurans for reproduction. Insular structural complexity was also evaluated in this regard. The results of correlation analyses of area vs. species richness and species richness vs. number of reproductive habitats were highly significant indicating that species richness prediction in fragmented environments depends on both factors. Nestedness analyses using the metric NODF was performed in an attempt to investigate whether shared species absences among the islands are the result of a random process or represents a pattern indicative of ordered loss of species. The predicted pattern was confirmed ? that is, that species loss is nonrandom and that this was possibly caused by habitat loss. The role played by climatic events at the beginning of the Holocene and of the availability of reproductive habitats in the islands upon species loss is discussed. Furthermore, it is discussed how these results can help to guide conservation strategies of anuran species. / BITTENCOURT-SILVA, Gabriela Bueno. Comunidades de Anf?bios Anuros Insulares do Litoral Sudeste do Brasil: Composi??o Taxon?mica e Rela??es com a Hist?ria de Forma??o das Ilhas. 2011. 72p. Disserta??o (Mestrado em Biologia Animal). Instituto de Biologia, Departamento de Biologia Animal, Universidade Federal Rural do Rio de Janeiro, Serop?dica, RJ, 2011. Atrav?s de invent?rios e compila??o de dados da literatura levantou-se a composi??o de esp?cies de anf?bios anuros de oito ilhas, sendo seis da Costa Verde do Estado do Rio de Janeiro e duas do litoral norte do Estado de S?o Paulo. Al?m das ilhas, foram tamb?m compilados da literatura os invent?rios de duas comunidades representativas do litoral dos dois Estados. Adicionalmente, foram registradas 67 esp?cies, pertencentes a 11 fam?lias de anuros nas ilhas e 117 esp?cies e 14 fam?lias para o continente. O padr?o de distribui??o de riqueza das ilhas foi avaliado em rela??o ? ?rea das ilhas, ? composi??o de ambientes usados pelos anuros para reprodu??o e ? complexidade estrutural das ilhas. As an?lises de correla??o da riqueza de esp?cies vs. ?rea e riqueza de esp?cies vs. n?mero de ambientes reprodutivos apresentam resultados significativos, que s?o indicativos que a riqueza de esp?cies em ambientes fragmentados depende da intera??o de ambos os fatores. A fim de avaliar se as aus?ncias compartilhadas de esp?cies entre as ilhas ocorrem ao acaso ou encontram-se estruturadas, realizou-se uma an?lise de aninhamento com o aux?lio da m?trica NODF. O padr?o previsto foi confirmado e a perda de diversidade ? discutida em rela??o ? eventos clim?ticos do in?cio do Holoceno e ? disponibilidade de ambientes reprodutivos nas ilhas. Discute-se ainda como os resultados desse estudo podem servir para orientar programas de conserva??o de esp?cies de anf?bios anuros

Made available in DSpace on 2014-12-17T15:55:05Z (GMT). No. of bitstreams: 1 RobertoR_DISSERT.pdf: 1125393 bytes, checksum: 639c9308ec555425dc29f7b3bad222f8 (MD5) Previous issue date: 2014-01-31 / The diversity of fish species from South America has been affected by various anthropogenic practices. Some studies have reported the influence that illegal transferring or introduction of exotic species have on the trophic webs of continental lakes. The loss of diversity on fish populations and consequent impacts on fishery are commonly evidenced in these cases. The Brazilian Northeast has ponds for which exotic Amazonian species were transferred as Extremoz Lake. These environments serve as study models for comparison and investigation about the possible impacts of these introductions. We tested the hypothesis that loss of species that this trend can be related with the insertion of the genus Cichla, commonly documented as top predator in its endemic environment. Possible structural causes that interfere in other processes such as migration were also investigated. Thus, the local ecological knowledge of fishermen and a current ecotrophic model were used. We took samples of phytoplankton, zooplankton and fishes during two annual cycles. Concurrently, we made interviews with the fishing community. In fact, there are relations between the loss of fish and the insertion of peacock bass in Extremoz Lake. However, Cichla kelberi was not indicated as primary factor to explain fish species decline. The construction of bridges located in the Rio Doce was main factor for respondents and what explains loss of species. The migration of saltwater fish and / or from the river to Extremoz Lake is hindered by the unsuitability of the crossing-streams that are under these structures. According to the ecotrophic model Hoplias malabaricus was considered key-species and Cichla kelberi top predator. This last trend was similarly noticed in the stomach and local ecological knowledge of fishermen analysis. Overfishing simulations to Cichla kelberi resulted that only raising its captures in 200%, other native species would increase their biomass values only 15 to 30% (in 6 years).The negative effects of the alien species introduction without prior studies and lack of investments in appropriating these constructions to the needs of the fish fauna structures seem to act simultaneously. Both are causing the decline of fish species richness and consequent local artisanal fishery collapse / A diversidade de esp?cies de peixes da Am?rica do Sul vem sendo afetada por diversas pr?ticas antr?picas. Alguns estudos t?m documentado os efeitos resultantes destas transfer?ncias ilegais de esp?cies ex?ticas. A perda de riqueza da ictiofauna e consequente desarticula??o da pesca t?m sido evidenciadas nestes casos. O nordeste brasileiro apresenta lagoas para as quais foram transferidas esp?cies ex?ticas amaz?nicas, como a Lagoa de Extremoz. Estes ambientes servem como modelos de estudo para fins de compara??o e investiga??o dos poss?veis impactos decorrentes destas introdu??es. Testamos a hip?tese de que a perda de riqueza da ictiofauna e consequente desarticula??o da pesca artesanal exibem rela??o com a inser??o do g?nero Cichla, comumente documentado como predador de topo em seu ambiente end?mico. Poss?veis causas estruturais que interferissem em outros processos, como os de migra??o, tamb?m foram investigadas. Para tanto, o conhecimento ecol?gico local dos pescadores e um modelo ecotr?fico atual foram utilizados. Durante dois ciclos anuais, efetuamos amostragens de fitopl?ncton, zoopl?ncton e peixes. Concomitantemente, efetuamos entrevistas com a comunidade de pescadores. Segundo os resultados obtidos, pode-se inferir que existe um padr?o de queda de riqueza das esp?cies de peixes da lagoa de Extremoz. Por?m, Cichla kelberi n?o foi indicado como fator principal para que este decl?nio viesse a ocorrer. A constru??o de pontes, localizadas no Rio Doce, foi apontada pelo conhecimento ecol?gico local como fator prim?rio para que o n?mero de esp?cies diminu?sse neste ambiente. A migra??o de peixes de ?gua salgada e/ou provenientes do Oceano Atl?ntico para a Lagoa de Extremoz parece ter sido impedida com os impactos causados por estas obras c?veis, especialmente no que diz respeito ? inadequa??o das manilhas ?s necessidades da ictiofauna. Segundo o modelo ecotr?fico, Hoplias malabaricus foi considerada esp?cie-chave e Cichla kelberi predador de topo, tend?ncia similarmente obtida nas an?lises estomacais e atrav?s do conhecimento ecol?gico local dos pescadores. Simula??es de sobre pesca para o tucunar? indicaram inviabilidade em rela??o ao aumento da captura desta esp?cie. Em 6 anos, mesmo aumentando a pesca de tucunar? em 200%, outras esp?cies poderiam aumentar sua biomassa somente em 15 e 30%. A influ?ncia negativa da inser??o de esp?cies ex?ticas sem estudo pr?vio para determinados ambientes e a falta de investimento em estruturas adequadas ?s necessidades da ictiofauna parecem atuar simultaneamente, causando o decl?nio da riqueza de esp?cies e consequente colapso da pesca artesanal local

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