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Ledarskap i förändring - vad hände med ledarna under Covid-19 pandemin? : En kvalitativ studie om en Black Swan i fastighetsförvaltningsbranschen ur ett ledarperspektiv.Hellström, Anton, Lilja, Calle January 2022 (has links)
Syfte: Syftet med studien är att öka kunskapen och förståelsen om fastighetsförvaltningsbranschen under en Black Swan ur ett ledarperspektiv och strävar efter att besvara frågeställningen: vad har förändrats för ledarna inom fastighetsförvaltningsbranschen under Covid-19 pandemin? Metod: Insamlingen av empiri har skett genom semi-strukturerade intervjuer av nio respondenter som är ledare på olika nivåer i de fem organisationer som är representerade i studien. Resultatet från de digitala intervjuerna har transkriberats, kodats och reducerats för att utgöra grunden i formandet av studiens teori utifrån en induktiv ansats. Resultat och slutsats: Studien visar att ledarskapet under pandemin kännetecknats av hierarkiska strukturer och auktoritära tendenser med ett ökat fokus på styrning och kontroll. De väsentliga faktorerna som förändrats för ledarna är distansarbete och digitala mötesformer vilket resulterat i ökad kommunikation och en förflyttning från strategiskt till operativt arbete. I studien identifieras även ett rationalitetsdilemma och en identitetsparadox inom branschen. Examensarbetets bidrag: Studien bidrar med kunskap och förståelse till tidigare forskning om ledares utmaningar, förändrade förutsättningar och hur ledarskapet utövats under Covid-19 pandemin. Arbetet bidrar även med empiri om ledarskapet inom fastighetsförvaltning, ett område som tidigare är förhållandevis outforskat inom ämnet Ledarskap och Organisationer. Förslag till fortsatt forskning: Fördjupade studier är nödvändiga om ledarskapet i fastighetsförvaltningsbranschen där även medarbetarperspektivet inkluderas. Det existerar även ett behov för jämförande studier mellan branscher som påverkats på andra sätt av Covid-19 alternativt hade en mer flexibel struktur och arbetssätt före pandemin. / Aim: The study aims to add to the knowledge and understanding about the property management industry during a Black Swan event from a leader perspective and strive to answer the question: what changed for leaders in the property management industry during the Covid-19 pandemic? Method: Data collection was executed through semi-structured interviews of nine respondents who are leaders on various levels in the five organizations represented in the study. Results from the digital interviews were transcribed, coded and reduced in order to be the base for the study’s theory from an inductive approach. Result and conclusion: The study shows that the leadership during the pandemic were characterized by hierarchical structures and authoritative tendencies with focus on management and control. Factors that have changed for leaders are primarily remote work and digital meetings which have resulted in increased communication and turn from a strategic focus to an operational. The study also identifies a rationalization dilemma and an identity paradox within the business. Contribution of the thesis: The study adds to the understanding and knowledge of previous research on challenges, changed conditions and how the leadership is executed during the Covid-19 pandemic. It also adds empirical findings on leadership in the property management industry, a field with previously limited research within the subject Leadership and Organizations. Suggestion for future research: Additional studies are needed about leadership within property management organizations where the employee perspective is included. Also, comparative studies are needed in other business fields where the pandemic has had a greater impact or in organizations that had a more flexible structure before the pandemic.
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”I just want to be perfect” : En kvalitativ komparativ textanalys av perfektionister i filmerna Black Swan och Whiplash / “I just want to be perfect” : A qualitative comparative textual analysis of perfectionists in the movies Black Swan and WhiplashJahrehorn, Frans, Kvist, Rebecka January 2023 (has links)
The aim of this study is to analyze how the depiction of a young male and female protagonist who persistently seek success differs and which film techniques are used to depict male and female perfectionism. Since 1989, young people, especially in the cultural sphere, have stated that they feel an increasing pressure from their surroundings and from themselves compared to previous generations. The strive to be successful causes anxiety, depression, and perfectionism, where the latter has been linked to narcissism. Previous studies have found that media, especially film, has a crucial impact on how viewers perceive people with mental illnesses and stereotypes concerning gender, and the exposure to gender stereotypes may influence the viewers’ physical states and attitudes. This study adopts a qualitative comparative textual analysis using case studies, with an approach called neoformalism focusing on three formal levels: narrative, stylistic and thematic. The study also includes theories from feminist film studies. The films used as case studies are Black Swan (2010) directed by Darren Aronofsky and Whiplash (2014) directed by Damien Chazelle. The result show that differences between male and female are prominent on all three levels of the film form. Nina in Black Swan needs to rely on sex to succeed and she gets punished in the end for the transgression, while Andrew in Whiplash simply practices to reach perfection. The film techniques used show more pictures of Nina's body and female props like mirrors while Andrew is shown solely around musical instruments. They are also both perfectionists and narcissists, but overall, Nina is shown to be more irrational and paranoid than Andrew and these psychological qualities are reflected in and communicated by the formal system of the films.
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Gulbių nebylių (Cygnus olor) sankaupų gausa, formavimosi ir pasiskirstymo ypatumai Lietuvos žuvininkystės ūkiuose / Abudance of mute swan (cygnus olor) flocks in the fishponds complexes of lithuania, characteristics of formation and distributionMikalauskienė, Agnė 25 June 2014 (has links)
2009 metais devyniolikoje (su padaliniais dvidešimt viename) Lietuvos žuvininkystės ūkių buvo vykdomi gulbių nebylių sankaupų gausos, formavimosi sezoninės dinamikos ir pasiskirstymo ypatumų tyrimai. Tyrimai užpildo eilę spragų ankstesniuose tyrimuose apie gulbių nebylių sankaupų formavimąsi žuvų tvenkiniuose. Sankaupų formavimosi laikotarpiu žuvų auginimo tvenkiniais naudojasi apie tris tūkstančius neperinčių gulbių nebylių. Paukščiai čia apsistoja sezoninių migracijų metu. Taip pat čia susirenka šertis nesiveisiantys individai. Gulbių buvimo žuvininkystės ūkių tvenkiniuose trukmę apsprendžia tvenkinių pripildymo (balandžio mėn.) ir nuleidimo (intensyviausiai rugsėjo antroje - spalio pirmoje pusėje) laikotarpiai. Sankaupos gausiausios pavasario pabaigoje - vasaros pradžioje, visų pirma birželio mėnesį, tačiau jų dydis atskiruose ūkiuose ženkliai svyruoja ir gali piką pasiekti ir kitais sezono laikotarpiais, ypač rudeniop. Stabiliai pagrindiniu, sankaupų dydį konkrečiuose žuvų ūkiuose apsprendžiančiu, veiksniu yra bendras tvenkinių, kuriuose buvo beriami žuvų pašarai, plotas. Ūkiuose (jų grupėse), kuriuose šio faktoriaus skaitinė reikšmė didelė, gulbių nebylių sankaupos taip pat didelės ir atvirkščiai. Tačiau atsitiktinė natūralių buveinių su gausiomis gulbių nebylių sankaupomis (pavyzdžiui Kuršių Marių) kaimynystė (geografinis faktorius), gali nusverti anksčiau minėto faktoriaus poveikį. Gulbės sankaupose naudoja didžiąją dalį konkretaus, ūkio tvenkinių (paprastai 50-70 %) –... [toliau žr. visą tekstą] / In 2009, research was carried out on abundance of mute swan flocks, its formation, seasonal dynamics and distribution characteristics in nineteen (with branches in twenty-one) fish farms in Lithuania. This research fills-in a number of gaps of previous studies on mute swan flocks formation in fish farm ponds. Around three thousand non breeding mute swans are using fish farming ponds during flock’s formation season. Birds stay here during seasonal migrations. Also non breeding swans gather here to moult. The duration of stay of swans in fish farm ponds is determined by the time of filling up (in April) and draining (most intensive in the second half of September and in the first half of October) of ponds. The most numerous flocks are at late spring - early summer, particularly in June, but the size of individual flocks vary considerably and may reach peak during other periods of the season, especially in autumn. The most stable factor determining size of the specific flock in fish farm ponds is area of the pond where fish are fed. Flocks are more numerous in farms (or groups of farms) in which value of this factor is higher and vice versa. However, random natural dwellings of mute swan flocks with large populations (for example neighborhood of Kuršių Marios – geographical factor) may outweigh the above factor’s impact on mute swans flock size in fish ponds. Flocks of mute swans cluster during the mobilization period and use most part of the fish farm pond (usually 50-70%) –... [to full text]
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Evolução da órtese Anel em Oito Articulado (AOA) / Evolution of the articulated eight-shaped ring orthosis (AOA)Masalskas, Ellen Cristina 25 October 2018 (has links)
A deformidade em pescoço de cisne é uma postura anormal do dedo caracterizada por hiperextensão da articulação interfalangeana proximal juntamente com a flexão da interfalangeana distal, que pode causar dor e incapacidade funcional. Na prática clínica, as órteses são amplamente aplicadas no tratamento conservador da deformidade, sendo indicados modelos adquiridos comercialmente ou confeccionados sob medida pelos terapeutas. Trabalhos anteriores do grupo de pesquisa propuseram um modelo de órtese articulada para correção da deformidade pescoço de cisne denominada AOA (Anel em Oito Articulado) que teve sua funcionalidade aprovada pelos voluntários da pesquisa. O presente trabalho objetiva a evolução deste projeto na busca de um modelo mais anatômico (maior conforto), mais funcional e melhorar a compreensão acerca da relação entre materiais, manufatura e custo da órtese. Para isto, foram utilizados os processos de Manufatura Aditiva (MA) ou impressão 3D e parametrização, que permite o redezenhar automaticamente a órtese. A metodologia aplicada foi baseada no desenvolvimento de produtos e otimização integrada entre a técnica e a participação de adultos, atendidos nos ambulatórios do HCFMRP-USP, que apresentam a deformidade a fim de identificar sua percepção acerca da experimentação. A metodologia foi dividida didaticamente em duas etapas. Na primeira, foram realizadas as medidas antropométricas de dedos com a deformidade, além da definição das medidas de referência para parametrização através de medidas das mãos dos pesquisadores e de clientes; na segunda etapa, foi realizada a otimização e a parametrização do desenho, foi testada a manufatura da órtese com diferentes materiais, teste de usabilidade, por teste de bancada com os pesquisadores e após aprovação foram experimentadas por dois clientes para avaliar a opinião e na sequencia, foi feita análise descritiva dos dados. As principais alterações do projeto atual sobre o original foram a substituição dos diâmetros das seções dos dedos pela altura e largura que as aproximou de formatos elípticos; aumentos e reposicionamentos dos apoios ao dedo; reposicionamento do eixo de rotação da articulação; alteração do ângulo de bloqueio segundo recomendação do terapeuta pela avaliação da deformidade; modelagem paramétrica e manufatura aditiva em resina de alta resistência. Foram realizados também ensaios mecânicos para avaliação das propriedades das resinas curadas e teste com sensor de força, para conhecimento da distribuição de pressão da órtese no dedo. O presente modelo possibilitou aos usuários um ganho em funcionalidade e conforto e através do desenho paramétrico e manufatura aditiva direta possibilitou a dispensação da órtese personalizada com maior agilidade, em poucas horas. A evolução da AOA foi considerada promissora pois apresenta uma ferramenta inovadora muito próxima da aplicação comercial para a resolução de um problema de saúde crônico. / The swan neck deformity is an abnormal posture of the finger characterized by the hyperextension of the proximal interphalangeal joint with distal interphalangeal flexion, which can cause pain and lead to functional disability. In clinical practice, the orthosis is widely recommended in the conservative treatment of the deformity, and both commercially-acquirable models and on demand models made by therapists can be indicated. The previous work of the research group proposed an articulated orthosis model for the correction of swan neck deformity called AOA (Articulated Eight-shape Ring) that had its functionality approved by the research volunteers. The present work aims to further develop this project by searching for a more anatomical and functional model, providing greater comfort, and seeking a compromise among materials, manufacture and cost of the orthosis. For this, the processes of Additive Manufacturing (MA) or 3D printing and parameterization were used, which allows the automatic redesign of the orthosis The applied methodology was based on the product development and the integrated optimization between the technique and the feedback of adult patients who were affected by the deformity and treated at the HCFMRP-USP ambulatories. The methodology was divided into two steps: firstly, the anthropometric measurements of the fingers with the deformity were carried out, and the reference measurements for parameterization were defined through the measurement of the researchers\' and the patients\' hands; secondly, the optimization and parameterization of the design was performed, followed by the manufacturing of the orthosis with different materials that were submitted to usability tests and a bench test with the researchers. After approval, the orthosis were tested by two patients in order to obtain their opinion, and subsequently, the descriptive analysis of collected data was established. When comparing the current design to the original one, the main changes were the replacement of the diameters of fingers sections by slightly elliptical formats, the enlargement and repositioning of the finger supports, the repositioning of the rotation axis of the joint, the alteration of the blockage angle according to the recommendation of the therapist to evaluate the evolution of the deformity, and the parametric modelling and additive manufacture in high strength resin. Mechanical tests were also carried out to evaluate the properties of the cured resins as well as load sensor tests to identify the pressure distribution from the orthosis to the finger. The present model provided the users with greater functionality and comfort. Moreover, the personalized orthosis can be fabricated in matter of a few hours due to the parametric design and direct additive manufacture. The evolution of AOA was considered promising as it presents an innovative tool very close to the commercial application for the resolution of a chronic health issue.
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Sustainable Fashion Consumption and Consumer BehaviorZahid Iqba, Muhammad January 2011 (has links)
Thesis was carried out to make an estimation of the willingness of consumers to buy the clothes produced under eco-friendly and decent way. Neoclassic demand theory was used and basic idea was to know that either moral effects on a consumer’s individual decision while choosing the products manufactured under friendly environment or not; if yes, then how and how much. Survey method along with choice experiment analysis was used to collect the data. Selected area was Boras Sweden and 50 respondents were considered for the survey. To estimate the degree of willingness of a consumer to pay for a Swan labeled and/or Fairtrade labeled jeans, choice experiments was used. Afterwards, the collected data was used within econometric models. It has been observed from results that consumers were more willing to pay for a Swan labeled and/or Fairtrade labeled jeans than non-labeled jeans. The responsible individuals regarding environment were much more willing to pay for Fairtrade and/or Swan labeled clothes, considering the factor that production does not affect the environment in negative way and it was done under socially acceptable conditions. / Program: Magisterutbildning i Fashion Management
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Influência da posição do orifício de saída e do tipo da ponta do cateter sobre o risco de complicações mecânicas e infecciosas e sobrevida da técnica em pacientes em diálise peritoneal /Banin, Vanessa Burgugi January 2017 (has links)
Orientador: Pasqual Barretti / Resumo: Introdução: As complicações mecânicas e infecciosas associadas ao cateter de dialise peritoneal representam as principais causas de falência da técnica. Tais complicações podem estar associadas às configurações intra e extraperitoneal do cateter. Objetivo: comparar complicações mecânicas e infecciosas, além de sobrevida da técnica entre cateteres de Tenckhoff implantados com Orifício de Saída (OS) voltado para baixo e OS voltado para cima e cateteres de Swan Neck (ponta reta e ponta coil). Metodologia: estudo prospectivo randomizado que comparou complicações mecânicas (translocações) e infecciosas (peritonites e infecções de orifício de saída) entre cateteres divididos de maneira randomizada em quatro grupos: Tenkhoff OS baixo, Tenckhoff OS cima, Swan Neck ponta reta e Swan Neck ponta coil. Os grupos foram seguidos pelo período de um ano. O implante foi realizado pela equipe da Nefrologia utilizando a técnica de Seldinger. Resultados: no período de agosto de 2013 a fevereiro de 2016 foram implantados 107 cateteres em 96 pacientes. As características clinicas e demográficas foram semelhantes entre os pacientes nos quatro grupos. A análise da curva de sobrevida pelo método de Kaplan-Meier não mostrou diferenças para o tempo livre do primeiro episódio de infecção de OS (p=0,19) ou peritonite (p=0,29) entre os quatro grupos. Observamos no entanto, menor tempo livre até o primeiro episódio de translocação (p=0,03), menor sobrevida do cateter (p=0,001) e menor sobrevida da técnica ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Background: The mechanical and infectious complications associated with the peritoneal dialysis catheter represent the main causes of technique failure. Such complications may be associated with the intra- and extra-peritoneal configurations of the catheter. Purpose: The objectives of this study were to compare infectious and mechanical complications and technique survival among four randomized groups of PD catheters: straight Tenckhoff catheters implanted with downward Exit Site (ES), straight Tenckhoff implanted with upward ES, Swan-Neck coil tip and Swan-Neck straight tip. Methods: A prospective randomized trial comparing mechanical (translocations) and infectious (peritonitis and exit-site infection) complications between catheters randomly divided into four groups: Tenkhoff downward ES, Tenckhoff upward ES, Swan Neck straight tip and Swan Neck coil tip. The four groups were followed for one year. The implant was performed by the Nephrology team using the Seldinger technique. Results: In the period from August 2013 to February 2016, 107 catheters were implanted in 96 patients. The baseline demographics characteristics were similar among the groups. Analysis of the Kaplan-Meier survival curve showed no difference in the free time of the first episode of ES infection (p = 0.19) or peritonitis (p = 0.29) among the four groups. We observed, however, less free time for the first episode of translocation (p = 0.03), lower catheter survival (p = 0.001) and lower technique survi... (Complete abstract click electronic access below) / Doutor
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Dissipação de energia de ondas geradas por ventos em reservatórios de barragens, devido à presença de vegetação /Mattosinho, Germano de Oliveira. January 2016 (has links)
Orientador: Geraldo de Freitas Maciel / Resumo: A propagação de ondas geradas por vento em reservatórios de barragens de grande dimensão pode pôr em risco a geração de energia, segurança da navegação interior, bem como contribuir para a ocorrência de fenômenos erosivos recorrentes às margens desses reservatórios. O reservatório da barragem da UHE (usina hidrelétrica) de Ilha Solteira também se encontra exposto aos fenômenos de formação de ondas por ventos com possíveis efeitos econômicos e uma análise aprofundada envolve uma grande interdisciplinaridade. Dentro dessa perspectiva, e privilegiando medidas não-estruturais como soluções de engenharia de forma a mitigar ação de ondas no processo de erosão de margens do entorno do reservatório, este trabalho de mestrado visa quantificar, com apoio da simulação numérica, os coeficientes de atenuação de energia de ondas produzidas por ventos quando estas se propagam sobre fundos com vegetação. Neste estudo, são analisadas, utilizando-se o software SWAN-VEG, as alturas de ondas geradas para uma gama de ventos e sua atenuação, nos casos sem e com a presença de diversos cenários ou layouts de vegetação no fundo. Ainda é verificada a influência do efeito de refinamento de malhas (250, 150 e 100 m) no modelo sobre os coeficientes de atenuação. Análises comparativas com estudos da literatura são realizadas, apontando para a necessidade de se determinar, com acurácia, o coeficiente de arraste, C_D, no complexo fenômeno de atenuação de ondas propagando-se em águas confinadas com presença ... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
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"Is That What You Dream About? Being a Monster?": Bella Swan and the Construction of the Monstrous-Feminine in The Twilight SagaFirestone, Amanda Jayne 13 June 2014 (has links)
ABSTRACT
This dissertation argues that Bella Swan is a representation of Barbara Creed's monstrous-feminine which serves to reinforce ideologies that insist women are abject, inherently dangerous to men, and threatening to a patriarchal status quo. Through close-textual analysis of The Twilight Saga, I demonstrate how the monstrous-feminine frames the hysterical teenage body, hypersexuality, and eternal motherhood as simultaneously unacceptable and unavoidable. These negative women's stereotypes continue to persist in dominant popular culture, and this doublebind is overcome only by the impossible perfection of vampirism. The monstrous-feminine invites constructions of teenage bodies as unstable and unreliable, women's sexuality as dangerous and impure, and motherhood as a requirement for a complete identity. These constructions are particularly dangerous in Young Adult literature and particularly inspirational in fanfiction.
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An assessment of the nutrient stripping function of two constructed wetlands in the Swan-Canning EstuaryMajimbi, Abbey Aggrey January 2007 (has links)
The use of constructed wetlands and wet detention basins has proven to be highly effective in removing pollutants from industrial discharges and stormwater runoff throughout the world. This is attributed to design of the key treatment components in a constructed wetland, catchment source characteristics and climatic conditions. A disproportionate amount of research and monitoring effort has gone into constructed wetlands due to their cost effectiveness and ability to optimize multiple benefits. In Western Australia, several wetland monitoring studies on the role of constructed wetlands especially in Swan-Canning estuary have been done, but often do not address their design efficiencies in stormwater treatment. Two wetlands (Liege St and Tom Bateman wetland) constructed for nutrient stripping proximal to the Swan-Canning estuary have been monitored for two years. Liege St wetland was constructed to reduce the nutrients reaching the Canning River directly and improve the amenity value of the area. Similarly, Tom Bateman wetland was constructed to reduce nutrients of the Banister Creek catchment draining into the Canning River as well as for stormwater management and habitat use. Physicochemical and biological indicators were used to assess the nutrient stripping efficiency of the wetlands. In some cases, data from previous studies were used to determine the health and viability of the selected wetland sites. The limnological indicators used included; dissolved oxygen, pH, water temperature, electrical conductivity and nutrient levels. The biological included; bacteria, nutrients and chlorophyll in periphyton, macroinvertebrates and diatoms. Differences in the community structure of periphyton, macroinvertebrates and water quality were found from the inlet to the outlet in both Liege St and Tom Bateman wetlands. / Despite the poor water quality, Liege St wetland exhibited significant nutrient removal efficiencies for TP while Tom Bateman wetland had very high removal efficiency for TN. The TP removal in Liege St wetland was attributed to the design of key treatment components which included a gross pollutant trap, concrete lined sedimentation pond, vegetated sumplands, weirs and clay lining for the wetland bed. In contrast, Tom Bateman wetland lacked the above key treatment components. Additionally, the wetland experienced short-circuiting especially during high flow periods. The high TN removal in Tom Bateman wetland was attributed to assimilation by plants and micro-organisms especially by the dense growth of Potamogeton crispus observed on the wetland floor and the non- biological transformation processes such as volatilisation, sorption and sedimentation. The poor water quality of the inflow in both wetlands was attributed to catchment characteristics which were not fully investigated in this study. In an attempt to improve the nutrient stripping function of Liege St and Tom Bateman wetland, changes to the wetland design and routine maintenance were suggested for Tom Bateman and Liege St wetland respectively. Also the use of the Swan-Canning Cleanup Programe (SCCP) water quality targets as opposed to the ANZECC trigger values in water quality assessments in constructed wetlands in the Swan-Canning estuary is suggested among others.
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Relationships between benthic macroinvertebrate assemblages and habitat types in nearshore marine and estuarine waters along the lower west coast of AustraliaM.Wildsmith@murdoch.edu.au, Michelle Wildsmith January 2007 (has links)
The following four broad aims were addressed in this study. (1) To ascertain whether the characteristics of the benthic macroinvertebrate assemblages within the different nearshore marine habitat types identified by Valesini et al. (2003) on the lower west coast of Australia differ significantly, and whether the pattern of those spatial differences matches those among the environmental characteristics that were used to distinguish those habitat types; (2) To develop a quantitative approach for classifying nearshore habitats in estuarine waters that employs readily-available data for a range of enduring environmental characteristics, and to use that approach to classify the various habitat types present in nearshore waters of the Swan-Canning Estuary on the lower west coast of Australia; (3) To test the hypothesis that the characteristics of the benthic macroinvertebrate assemblages in the in the Swan-Canning Estuary differ significantly among nearshore habitat types, and that the pattern of those differences matches that among the environmental characteristics used to distinguish those habitat types and (4) To test the hypothesis that, as a result of environmental changes in the Swan-Canning Estuary, the characteristics of the benthic macroinvertebrate assemblages at various habitats in this estuary in 1986/7 differ from those in 2003/4.
To address the first aim, benthic macroinvertebrates were sampled seasonally for one year in the subtidal waters and intertidal zone (upper and lower swash zones) at the six nearshore habitat types that were identified by Valesini et al. (2003) on the lower west coast of Australia. The habitat types, which differed mainly in the extent of their exposure to wave activity and whether seagrass and/or nearshore reefs were present, had been distinguished quantitatively using values for a suite of seven statistically-selected enduring environmental characteristics. The faunal samples yielded a total of 121 species representing eight phyla, among which the Polychaeta, Malacostraca and Bivalvia were the most speciose classes and contributed ~ 38, 23 and 10%, respectively, to the total number of individuals. The total number of species and mean density of macroinvertebrates was far greater at the most protected habitat type (1), which also contained dense beds of seagrass, than at any other habitat type, i.e. 70 species and 209.2 individuals 0.1 m-2, compared to 32 species and 36.9 individuals 0.1 m-2 at the most exposed habitat type (6), which had a substrate comprised only of sand. Differences among habitat type influenced the benthic macroinvertebrate species composition to a greater extent than differences among either zones or seasons. Significantly different faunal compositions were detected among those latter two factors only at the most protected habitat type. The faunal assemblage at habitat type 1 was clearly the most distinct from those at the other five habitat types, particularly in the subtidal zone (R-statistics=0.642-0.831, p=0.1%), and was typified by five abundant polychaete species that were adapted to deposit-feeding. In contrast, the fauna at habitat type 6 was typified by four crustacean species and a species of bivalve and polychaete, whose mobility and tough external surface facilitated their survival and feeding in those turbulent waters. The extents of the differences in species composition among the six habitat types was significantly matched with that among the suite of enduring environmental characteristics that distinguished those habitat types, particularly in the case of the subtidal zone (Rho=0.676). Such results indicated that the environmental variables used to distinguish the nearshore habitat types could be used to reliably predict the types of benthic macroinvertebrate species likely to occur at any site along the lower west coast of Australia.
The above biological validation of the nearshore marine habitat classification scheme developed by Valesini et al. (2003) provided the justification for the approach to the second broad aim of this study, namely to develop a quantitative scheme for classifying habitat types in the Swan-Canning Estuary. This approach was similar to that employed by Valesini et al. (2003) in that it considers that differences among habitat types are well reflected by differences in a suite of enduring environmental variables. However, it improves on that earlier method by employing a completely objective and quantitative approach.
Thus, a large number of environmentally-diverse nearshore sites (102) were initially selected throughout the Swan-Canning Estuary and a suite of 13 enduring environmental variables quantified at each using remotely-sensed images of the estuary in a Geographic Information System. Such variables were chosen to reflect either (i) the type of substrate and submerged vegetation present, (ii) the extent of exposure to wave action or (iii) the location of the site within the estuary with respect to its vicinity to marine and fresh water sources. These data were then subjected to the CLUSTER routine and associated SIMPROF procedure in the PRIMER v6 multivariate statistical package to quantitatively identify those groups of sites that did not differ significantly in their environmental characteristics, and thus represented habitat types. Eighteen habitat types were identified, which were shown to well reflect spatial differences in a suite of non-enduring water quality and sediment characteristics that were measured in situ at a range of estuarine sites during both summer and winter in 2005 (Rho=0.683 and 0.740, respectively, p=0.1%). However, those latter environmental characteristics required far more time in the field and laboratory to quantify than the enduring variables used to identify the habitat types.
Benthic macroinvertebrates were sampled during summer and winter in 2005 in the shallow subtidal regions (~1 m depth) at sites representing eight of the habitat types identified in the Swan-Canning Estuary. These samples contained a total of 51 and 36 species during summer and winter, respectively, and, in both seasons, represented nine phyla, namely Annelida, Crustacea, Mollusca, Sipuncula, Nematoda, Platyhelminthes, Cnidaria, Uniramia and Nemertea. The compositions of the benthic macroinvertebrate assemblages differed significantly among habitat types and, to a similar extent, between seasons (Global R-statistic=0.408 and 0.409, respectively, p=0.1%). However, the spatial differences were considerable greater in winter than in summer (Global R-statistic=0.536 vs 0.280, p=0.1%), presumably due to the greater spatial variation in particular non-enduring in situ environmental characteristics, such as redox depth and salinity. While the number of species, overall density and taxonomic distinctness of benthic macroinvertebrates also differed significantly among habitats, those variables differed to a greater extent between seasons, being greater in winter than in summer. While the measures of taxonomic distinctness tended to be greater at habitat types located in the lower to middle reaches, i.e. habitat types 6, 7, 9, 10, 13 and 18, than the upper reaches i.e. habitat types 1 and 3, the number of species and overall density reflected this trend only during winter. During summer, the mean numbers of species at habitat types 1, 3, 6 and 10 (3.4-6.0) were significantly lower than those at habitat types 7, 13, and 18 (8.8-10.9), whereas the overall density of benthic macroinvertebrates was far greater at habitat type 7 (32260 individuals 0.1 m-2)than at any other habitat type in this season (3135-18552 individuals 0.1 m-2).
Overall, the greatest differences in assemblage composition occurred between those at habitat types 1 and 18 (R-statistic=0.669, p=0.1%), which were located in the uppermost region of the estuary and the lower reaches of the basin, respectively, and differed to the greatest extent in their enduring environmental characteristics. The assemblage at habitat type 1, and also that at habitat type 3, located just downstream, were relatively distinct from those at all other habitat types, particularly during winter (R-statistics=0.666-0.993, p=0.1%). The fauna at the first of these habitat types was relatively depauperate, containing low numbers of species and densities, and was characterised by the polychaetes Leitoscoloplos normalis and Ceratonereis aequisetis and the bivalve Arthritica semen. The assemblage at habitat type 3 was also characterised by those three species and the amphipod Paracorophium minor and the polychaete Boccardiella limnicola. In contrast, the assemblage at habitat type 18 was characterised by a more diverse assemblage, i.e. the polychaetes Capitella capitata, C. aequisetis, L. normalis and Pseudopolydora kempi, the amphipods, Grandidierella propodentata and Corophium minor and the bivalve Sanguinolaria biradiata. The number of species was among the highest at this habitat type during both seasons, which was also reflected in the high taxonomic diversity, and the overall density was the highest in winter and second highest in summer. Despite the above faunal differences, those between assemblages at habitat types 7 and 9, which were both located in the basin of the Swan-Canning Estuary, were similar in magnitude to those that occurred between pairs of habitat types located in two different regions of the estuary. Although both habitat types 7 and 9 were characterised by a similar suite of species, i.e. Oligochaete spp., C. aequisetis, C. capitata, C. minor, G. propodentata, L. normalis, and S. biradiata, the substantial differences in assemblage composition between these habitat types in both summer and winter (R-statistics=0.570 and 0.725, respectively) was due to marked differences in the relative contributions of each of these species.
Significant and strong correlations were shown to exist in both summer and winter between the pattern of differences in the benthic macroinvertebrate assemblages among habitat types and that among the enduring environmental characteristics used to identify those habitat types (Rho=0.625 and 0.825, respectively, p=0.1%). Furthermore, these correlations were greater than those obtained between the benthic macroinvertebrate fauna and any combination of the non-enduring environmental characteristics (i.e. water quality and sediment parameters) recorded in situ at each habitat type (Rho=0.508 and 0.824, in summer and winter, respectively, p=o.1%). This demonstrates the greater capacity of surrogate enduring environmental characteristics to account for differences in the range of variables that may influence the distribution of benthic invertebrate fauna. Thus, the lists of characteristic benthic macroinvertebrate taxa produced for each of the eight habitat types studied in the Swan-Canning Estuary provide a reliable benchmark by which to gauge any future changes in those fauna. Moreover, these results indicate that the above habitat classification scheme can be used to reliably predict the types of benthic macroinvertebrate fauna that are likely to occur at any nearshore site of interest in this estuarine system.
The final component of this study showed that the benthic macroinvertebrate assemblages at four sites in the middle reaches of the Swan-Canning Estuary in 2003/4 differed significantly from those recorded at the same sites in 1986/7. Such differences were reflected in (1) changes in the relative densities of a suite of ten species that were responsible for distinguishing the faunas in these two periods, (2) the absence of 22 rare species in 2003/4 (i.e. 42% of the number of species recorded in 1986/7), (3) the presence of 17 new species in 2003/4, including an abundant polychaete that is likely to have been introduced and (4) a far greater extent of seasonal variation in the number of species and densities of benthic macroinvertebrates in 2003/4. Such changes are likely to be related to lower sediment oxygen levels in certain seasons in 2003/4, as well as an altered hydrological regime due to increased temperatures and decreased rainfall in that more recent period. The fact that these changes have occurred within the Swan-Canning Estuary highlights the need for effective management tools, such as the habitat classification scheme and associated faunal survey undertaken in this study. Such data will provide a sound basis by which to examine the ways in which fauna vary spatially within the system, and allow for the establishment of comprehensive benchmarks for detecting future changes.
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