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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Pimelodus maculatus e P. platicirris (Siluriformes: pimelodidae) no alto rio Paraná: caracterização morfológica, dieta e reprodução

Silva, Thiago Teixeira [UNESP] 19 June 2015 (has links) (PDF)
Made available in DSpace on 2016-02-05T18:29:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-06-19. Added 1 bitstream(s) on 2016-02-05T18:33:27Z : No. of bitstreams: 1 000854702_20160331.pdf: 203826 bytes, checksum: 1ebac8525210178cde68d5f3dc94aac0 (MD5) Bitstreams deleted on 2016-04-01T11:49:44Z: 000854702_20160331.pdf,. Added 1 bitstream(s) on 2016-04-01T11:50:37Z : No. of bitstreams: 1 000854702.pdf: 964941 bytes, checksum: 72b071f42665b4898dd311be97966786 (MD5) / Pimelodus maculatus e P. platicirris são espécies simpátricas e a primeira a mais abundante do gênero Pimelodus no alto rio Paraná. Por apresentarem padrões morfológicos parecidos, P. platicirris tem sido erroneamente identificada como P. maculatus. Nós as comparamos morfologicamente e descrevemos suas diferenças. Pimelodus platicirris carece de informações básicas sobre sua biologia. Diante disso, descrevemos a dieta e reprodução das duas espécies e as comparamos. As espécies diferem pelos padrões de coloração e alguns aspectos morfológicos como a altura da nadadeira adiposa, altura e comprimento da cabeça e altura do corpo. Suas dietas foram compostas basicamente dos mesmos itens alimentares, diferindo apenas na frequência dos itens consumidos. Ambas são onívoras, com alta plasticidade alimentar. A ausência de gônadas em estádio avançado de maturação não nos permitiu determinar o período de reprodução, nem afirmar que o trecho amostrado é utilizado como sitio de reprodução / Pimelodus maculatus e P. platicirris are sympatric species and the first the most abundant specie of the genus in the upper Paraná river. They have similar morphological patterns and P. platicirris has been wrongly identified as P. maculatus. In this study we compared them morphologically and describe their differences. Pimelodus platicirris lacks basic information about their biology. Therefore, we describe the diet and reproduction of both species and compared them. They differ by color patterns and some morphological features as the height of adipose fin, height and length of the head and body height. Their diets were composed basically of the same food items, but differed in frequency of items consumed. Both are omnivorous with high plasticity of feeding habitats. The absence of gonads in advanced maturation stage did not allow us to determine the reproduction period, nor to affirm if the sampled stretch is used as a site of reproduction
32

Estudo qualitativo e quantitativo da helmintofauna dos peixes Scomberomorus cavalla (Cuvier) e Scomberomorus maculatus (Mit-Chill) no litoral do Ceará, Brasil / Qualitative and quantitative study of the helminth fauna of Scomberomorus cavalla (Cuv.) e Scomberomorus maculatus (Mitch.) in Ceará Coast

Klein, Vera Lucia Mota January 1975 (has links)
Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2017-07-24T23:02:58Z No. of bitstreams: 1 200781.pdf: 2703929 bytes, checksum: d2ee131d8ae3372359b424e0732625b4 (MD5) / Made available in DSpace on 2017-07-24T23:02:58Z (GMT). No. of bitstreams: 1 200781.pdf: 2703929 bytes, checksum: d2ee131d8ae3372359b424e0732625b4 (MD5) Previous issue date: 1975 / Análise qualitativa e quantitativa dos helmintos que se encontravam infestando, 65peixes das espécies Scomberomorus cavalla (Cuvier) e 65 de Scomberomorus maculatus (MitChill) na costa do Ceará. Foi observado que entre as duas espécies hospedeiras, a ca­vala foi a que apresentou maior Índice de parasitismo.Não foi comprovada qualquer influência do mês do ano, sexo ou idade do hospedeiro, na taxa de infestação helmíntiba. O grupo de helminto que mostrou o maior índice de infestação, foi o de nematódeo, representado 90,01% dos vermes da cavala e 86,34% da serra. Os helmintos encontravam-se em todos os Órgãos dos peixes, principalmente no estômago, onde eles se encontravam em maior número e mais frequentemente. Conclui-se que o termo “marca biológica”, seja aplica­do ao conjunto de parasitas que apresentaram maior lindice de infestação e não para cada espécie isoladamente. / ln this paper the author presents qualitative and quantitative analysis of the helminths parasites of Scomberomorus cavalla (Cuv.) e Scomberomorus maculatus (Mitch.) in Ceará Coast. Based on earlier on the host species in Ceará, the author adds biological data also refering to these species. It is shown through tables and graphics the helminths with the highest infestation frequency as well as the most infected parts. Of the hosts samples, Scomberomorus cavalla (Cuv.) presented the highest parasite índex. The infestation proved not to be due to the month of the yeat the samples were captured, age or sex of the hosts. The group which showed the highes·t infestation level in both host species, was composed by the nematodes, represented by 90,01% of helminths recovered from king mackerel and 86,34% from spanish mackerel. The helminths were recovered from all the parts of the body, mainly from the stomach, where they appered in great number and higher frequency. Prosohynchus atlanticus manther, 1940 and Rhadinorhynchus prsitis (Rudolphi, 1802), 1911 are fereded for the first time in Brazil. The conclusion suggests that the designation "biological tags" should be applied to the recovered helminths as a whole and not to a single species.
33

Pimelodus maculatus e P. platicirris (Siluriformes: pimelodidae) no alto rio Paraná : caracterização morfológica, dieta e reprodução /

Silva, Thiago Teixeira. January 2015 (has links)
Orientador: Francisco Langeani Neto / Banca: Roberto Goitein / Banca: Gianmarco Silva David / Resumo: Pimelodus maculatus e P. platicirris são espécies simpátricas e a primeira a mais abundante do gênero Pimelodus no alto rio Paraná. Por apresentarem padrões morfológicos parecidos, P. platicirris tem sido erroneamente identificada como P. maculatus. Nós as comparamos morfologicamente e descrevemos suas diferenças. Pimelodus platicirris carece de informações básicas sobre sua biologia. Diante disso, descrevemos a dieta e reprodução das duas espécies e as comparamos. As espécies diferem pelos padrões de coloração e alguns aspectos morfológicos como a altura da nadadeira adiposa, altura e comprimento da cabeça e altura do corpo. Suas dietas foram compostas basicamente dos mesmos itens alimentares, diferindo apenas na frequência dos itens consumidos. Ambas são onívoras, com alta plasticidade alimentar. A ausência de gônadas em estádio avançado de maturação não nos permitiu determinar o período de reprodução, nem afirmar que o trecho amostrado é utilizado como sitio de reprodução / Abstract: Pimelodus maculatus e P. platicirris are sympatric species and the first the most abundant specie of the genus in the upper Paraná river. They have similar morphological patterns and P. platicirris has been wrongly identified as P. maculatus. In this study we compared them morphologically and describe their differences. Pimelodus platicirris lacks basic information about their biology. Therefore, we describe the diet and reproduction of both species and compared them. They differ by color patterns and some morphological features as the height of adipose fin, height and length of the head and body height. Their diets were composed basically of the same food items, but differed in frequency of items consumed. Both are omnivorous with high plasticity of feeding habitats. The absence of gonads in advanced maturation stage did not allow us to determine the reproduction period, nor to affirm if the sampled stretch is used as a site of reproduction / Mestre
34

Aspectos da biologia populacional de Pimelodus maculatus (Teleostei: Siluformes), sob a influência de sitemas de piscicultura em tanques-rede /

Ramos, Igor Paiva. January 2009 (has links)
Orientador: Edmir Daniel Carvalho / Banca: Mário Luiz Orsi / Banca: Angelo Antonio Agostinho / Resumo: Atualmente a implantação de sistemas de pisciculturas em tanques-rede, pode ser mais uma forma de impacto sobre a biota e a qualidade da água, das represas brasileiras. Esta atividade disponibiliza recursos como sobra de rações, efluentes e abrigo à ictiofauna residente. Assim, o presente trabalho tem como objetivo caracterizar a influência de sistemas de pisciculturas em tanques-rede sobre a dieta e dinâmica populacional de uma espécie de peixe nativo, Pimelodus maculatus (Pimelodidae, Siluriformes) a mais abundante nas adjacências desses empreendimentos na represa de Chavantes - SP/PR. Dos exemplares capturados na área de influência dos tanques-rede (Tanque) e na área referencial (Controle) foram obtidos os seguintes dados biológicos: comprimento padrão, peso total, sexo, grau de repleção estomacal. Ainda, os estômagos com itens alimentares foram retirados e fixados. Em termos de dieta, os itens foram pesados e identificados até o nível taxonômico mais inferior possível. A partir destes dados foram calculados o grau de repleção médio (GRM), atividade alimentar (Aa) e índice de importância alimentar (IAi), relação peso/comprimento, fator de condição, taxa de crescimento entre outros. Os resultados mostram que há diferenças quanto ao GRM, Aa e IAi entre os exemplares do trecho Tanque e Controle. Assim, para os exemplares do trecho Tanque a principal categoria alimentar é Ração (97,08), enquanto que para os exemplares do trecho Controle é Detrito (27,30), Insetos aquáticos (22,35), Vegetais (21,48) e Moluscos (21,46). Referente à dinâmica populacional com enfoque no crescimento estimou-se o fator de condição, relação peso/comprimento e taxas/curvas de crescimento em comprimento e peso. Os resultados demonstraram que no entorno dos tanques-redes, os valores de comprimento padrão e peso total são maiores em relação ao trecho Controle (p<0,0001)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The development of cage fish farming may be considered a new form of impact in the aquatic biota and water quality in Brazilian reservoirs. This activity provides resources to the resident fishes, as ration, effluent, and refuge. Thus, this work aims to characterize the influence of systems in cage fish farms in the diet and population dynamics of a native fish species, Pimelodus maculatus the most abundant in the vicinity of these enterprises in the Chavantes Reservoir - SP / PR. The standard length, weight, sex, degree of stomach fullness were obtained of specimens captured in the influence area of the cage farms (Cage farm) and the reference area (Control), and the stomachs with contents were removed and fixed. The food items were weighed and identified to the lowest possible taxonomic level. From these data were calculated the degree of fullness average (GRM), feeding activity (Aa) and Alimentary Index (AI), the weight/length, condition factor and growth rate. The results show that there are differences in the GRM, Aa and IAi between fishes from the Cage farm and Control stretches. Thus, Cage farm stretch presented Ration as its main food category (97.08), while in the diet of Control stretch fishes the main food resources were Detritus (27.30), Aquatic insects (22.35), Vegetal matter (21.48) and Molluscs (21.46). The population dynamics, focusing on growth were estimated the condition factor, weight/length relationship and rates/curves of growth in length and weight. The results demonstrated that for the Cage farm stretch, the values of standard length and total weight are larger in relation to Control stretch (p <0.0001). For the weight/length relationship there are significant differences between the stretches for males (t = 2.3301), females (t = 2.5853) and male + female + undefined (t = 3.5636), reinforced by the highest growth rate observed in the Cage farm stretch... (Complete abstract click electronic access below) / Mestre
35

Aspectos da biologia populacional de Pimelodus maculatus (Teleostei: Siluformes), sob a influência de sitemas de piscicultura em tanques-rede

Ramos, Igor Paiva [UNESP] 20 February 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-20Bitstream added on 2014-06-13T21:00:35Z : No. of bitstreams: 1 ramos_ip_me_botib.pdf: 1690908 bytes, checksum: e5894e9a539c338fd7cd1881c08ebe73 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Atualmente a implantação de sistemas de pisciculturas em tanques-rede, pode ser mais uma forma de impacto sobre a biota e a qualidade da água, das represas brasileiras. Esta atividade disponibiliza recursos como sobra de rações, efluentes e abrigo à ictiofauna residente. Assim, o presente trabalho tem como objetivo caracterizar a influência de sistemas de pisciculturas em tanques-rede sobre a dieta e dinâmica populacional de uma espécie de peixe nativo, Pimelodus maculatus (Pimelodidae, Siluriformes) a mais abundante nas adjacências desses empreendimentos na represa de Chavantes – SP/PR. Dos exemplares capturados na área de influência dos tanques-rede (Tanque) e na área referencial (Controle) foram obtidos os seguintes dados biológicos: comprimento padrão, peso total, sexo, grau de repleção estomacal. Ainda, os estômagos com itens alimentares foram retirados e fixados. Em termos de dieta, os itens foram pesados e identificados até o nível taxonômico mais inferior possível. A partir destes dados foram calculados o grau de repleção médio (GRM), atividade alimentar (Aa) e índice de importância alimentar (IAi), relação peso/comprimento, fator de condição, taxa de crescimento entre outros. Os resultados mostram que há diferenças quanto ao GRM, Aa e IAi entre os exemplares do trecho Tanque e Controle. Assim, para os exemplares do trecho Tanque a principal categoria alimentar é Ração (97,08), enquanto que para os exemplares do trecho Controle é Detrito (27,30), Insetos aquáticos (22,35), Vegetais (21,48) e Moluscos (21,46). Referente à dinâmica populacional com enfoque no crescimento estimou-se o fator de condição, relação peso/comprimento e taxas/curvas de crescimento em comprimento e peso. Os resultados demonstraram que no entorno dos tanques-redes, os valores de comprimento padrão e peso total são maiores em relação ao trecho Controle (p<0,0001)... / The development of cage fish farming may be considered a new form of impact in the aquatic biota and water quality in Brazilian reservoirs. This activity provides resources to the resident fishes, as ration, effluent, and refuge. Thus, this work aims to characterize the influence of systems in cage fish farms in the diet and population dynamics of a native fish species, Pimelodus maculatus the most abundant in the vicinity of these enterprises in the Chavantes Reservoir - SP / PR. The standard length, weight, sex, degree of stomach fullness were obtained of specimens captured in the influence area of the cage farms (Cage farm) and the reference area (Control), and the stomachs with contents were removed and fixed. The food items were weighed and identified to the lowest possible taxonomic level. From these data were calculated the degree of fullness average (GRM), feeding activity (Aa) and Alimentary Index (AI), the weight/length, condition factor and growth rate. The results show that there are differences in the GRM, Aa and IAi between fishes from the Cage farm and Control stretches. Thus, Cage farm stretch presented Ration as its main food category (97.08), while in the diet of Control stretch fishes the main food resources were Detritus (27.30), Aquatic insects (22.35), Vegetal matter (21.48) and Molluscs (21.46). The population dynamics, focusing on growth were estimated the condition factor, weight/length relationship and rates/curves of growth in length and weight. The results demonstrated that for the Cage farm stretch, the values of standard length and total weight are larger in relation to Control stretch (p <0.0001). For the weight/length relationship there are significant differences between the stretches for males (t = 2.3301), females (t = 2.5853) and male + female + undefined (t = 3.5636), reinforced by the highest growth rate observed in the Cage farm stretch... (Complete abstract click electronic access below)
36

Evaluation of the alimentary biosseguranÃa of beans genotypes caupi (Vigna unguiculata L. WALP) susceptible and resistant to the Callosobruchus maculatus (FABR. 1775) / AvaliaÃÃo da biosseguranÃa alimentar de genÃtipos de feijÃo caupi (Vigna unguiculata L. WALP) suscetÃvel e resistente ao Callosobruchus maculatus (FABR. 1775 )

Silvia Maria Alves de Paula 12 June 2008 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Brazil is one of the largest producers of cowpea [Vigna unguiculata (L.) Walp.], a very important legume for human dietary protein and carbohydrate supply. Nevertheless, there are some factors which limit its productivity and utilization. The insect Callosobuchus maculatus (cowpea weevil) is considered the principal pest that attacks stored grains. In the Northeast of Brazil, breeding efforts involving cowpea have been directed towards the selection of high yielding varieties associated with traits of resistance to diseases and pests. However, studies on the nutritional quality of these improved genotypes are scanty. In this study, the research was conducted with two cowpea genotypes, BR9 Longà e IT81D 1053, susceptible and resistant to cowpea weevil, respectively, to evaluate whether the probable factors related to the resistance would interfere with the nutritional value. Proximate composition showed that both genotypes are good sources of proteins (23.45 and 26.61 g/100 g dry matter), carbohydrates (61.62 and 62.94 g/100 g dry matter) and crude fiber (4.32 and 5.20 g/100 g dry matter), presenting low contents of oil (3.30 and 3.89 g/100 g dry matter). Polyacrylamide gel electrophoresis of the seed flours showed similar patterns for both genotypes, except for the presence of a very prominent 29 kDa band in the resistant genotype. The presence of antinutritional factors such as lectin, urease and trypsin inhibitor was detected in both cowpea genotypes. Lectin (0.10 UH/mgF) and urease (25.13 and 25.41 U/gF) amounts were similar in the susceptible and resistant genotypes. The resistant genotype presented a higher content of trypsin inhibitor (18.55 mg trypsin inhibited/gF) than the susceptible one (12.57 mg trypsin inhibited/gF). Feeding trial conducted with rats fed the experimental diets containing seed flour of BR9 Longà and IT81D 1053 as the sole protein source, at 10% level, were not sufficient to promote animal growth compared to the animals fed the high quality diet containing egg white. However, when compared the treatments containing susceptible and resistant cowpea genotypes most of parameters analyzed were similar. Diets containing the chitin binding proteins (CBP), purified from susceptible and resistant cowpea genotypes and complemented / O Brasil à um dos grandes produtores de feijÃo caupi [Vigna unguiculata (L.) Walp.], uma importante leguminosa para consumo humano por ser boa fonte proteÃnas e carboidratos. Todavia, hà vÃrios fatores que limitam a produtividade e utilizaÃÃo dessa cultura, destacando-se o ataque pelo inseto Callosobruchus maculatus (gorgulho), conhecido como uma das principais pragas de armazenamento. No Nordeste do Brasil, genÃtipos de feijÃo caupi foram criados atravÃs de melhoramento genÃtico, visando aumento da produtividade e resistÃncia a doenÃas e pragas. PorÃm, à detectada a escassez de informaÃÃes relacionando resistÃncia e valor nutricional. Assim sendo, no presente estudo, dois genÃtipos melhorados geneticamente, BR9 Longà e IT81D 1053, suscetÃvel e resistente ao gorgulho, respectivamente, foram selecionados, para verificar se as alteraÃÃes promovidas pelo melhoramento afetariam sua qualidade nutricional. Os dados de composiÃÃo centesimal mostraram que ambos os genÃtipos constituem-se em boa fonte de proteÃnas (23,45 e 26,61 g/100 g de matÃria seca), carboidratos (61,62 e 62,94 g/100 g de matÃria seca) e fibra bruta (4,32 e 5,20 g/100 g de matÃria seca), apresentando baixos conteÃdos de lipÃdios (3,30 e 3,89 g/100 g de matÃria seca). Os perfis eletroforÃticos da farinha de sementes dos dois genÃtipos mostraram-se muito semelhantes entre si, exceto a existÃncia de uma banda mais proeminente na regiÃo de 29 kDa verificada no genÃtipo resistente. Fatores antinutricionais tais como lectina, urease e inibidor de tripsina foram verificados nos dois genÃtipos de feijÃo caupi avaliados. Os teores de lectina (0,10 UH/mgF) e de urease (25,13 e 25,41 U/gF) se mostraram bem similares nos genÃtipos suscetÃvel e resistente. Jà os conteÃdos de inibidor de tripsina foram diferentes, tendo o genÃtipo resistente apresentado maior atividade (18,55 mg de tripsina inibida/gF) em comparaÃÃo ao suscetÃvel (12,57 mg de tripsina inibida/gF). Farinhas dos genÃtipos BR9 Longà e IT81D 1053, quando incluÃdas em dietas para ratos como Ãnica fonte protÃica, a 10%, nÃo foram capazes de promover o crescimento dos animais de forma similar à albumina da clara do ovo (proteÃna padrÃo). Todavia, quando comparado o tratamento AvaliaÃÃo da BiosseguranÃa Alimentar de GenÃtipos... contendo farinha do genÃtipo suscetÃvel com aquele contendo o genÃtipo resistente, para a maioria dos parÃmetros analisados, as respostas foram bem parecidas. Dietas contendo proteÃnas ligantes à quitina (PLQ), purificadas do genÃtipo suscetÃvel e do resistente, complementadas com albumina da clara do ovo, apresentaram valor nutricional igual ou superior ao padrÃo (somente clara do ovo). Diante dos parÃmetros analisados, os resultados permitem concluir que o melhoramento genÃtico do feijÃo caupi, o qual conferiu resistÃncia ao Callosobruchus maculatus, nÃo foi capaz de alterar a qualidade nutricional dessa leguminosa. AlÃm disso, diferentemente ao verificado com o Callosobruchus maculatus, nÃo foram observados efeitos antinutricionais, tÃxicos e/ou alergÃnicos para os animais testados (ratos e camundongos), associados ao consumo das PLQ provenientes do genÃtipo suscetÃvel ou do resistente
37

Life history and reproductive fitness variation associated with the Y chromosome in Callosobruchus maculatus

Revenikioti, Maria January 2021 (has links)
In the seed beetle Callosobruchus maculatus, the female is the larger sex and the male is the smaller sex. However, males that are almost as large as females can also occur, which is due to a specific Y chromosome haplotype. This Y chromosome polymorphism is not expected since the Y chromosome does not recombine and has lost genetic variation as a consequence. Nevertheless, the Y chromosome manages to maintain this polymorphism. Thus, the questions asked are how this occurs and how the large male Y haplotype persists to exist since previous studies have shown how small males have the higher fitness. In this study, large males were from line SL3b Y and small males were from line SL1b Y. To answer the questions, two important measures of fitness were conducted, mating- and lifetime reproductive success, as well as lifetime-history traits of the SL1b Y and SL3b Y males. Males from line SL3b Y turned out to have a faster growth rate and a shorter development time compared to the SL1b Y males. Both the SL3b Y males with a shorter development time and the SL1b Y males with a longer development time had larger body sizes. Large males also showed to have heavier ejaculate weight and produced more offspring compared to the other male Y haplotype. However, neither of the males had higher pre-mating success. In conclusion, the two male Y haplotypes must coexist in nature since their traits are beneficial in different environments and circumstances.
38

Mechanisms of reproductive interference in seed beetles: experimental tests of alternative hypotheses / マメゾウムシ2種における繁殖干渉の機構:対立仮説の実験的検証

Kyogoku, Daisuke 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18826号 / 理博第4084号 / 新制||理||1587(附属図書館) / 31777 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 曽田 貞滋, 准教授 渡辺 勝敏, 教授 高橋 淑子 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
39

Implications of past and future vegetation change for the lizard fauna of Motunau Island

Bannock, Carol A. January 1998 (has links)
Abundance, distribution and habitat preferences of the lizard species present on Motunau Island, off the Canterbury coast of New Zealand, were investigated. The aim of the study was to investigate the extent to which recent vegetation change on Motunau Island has effected the lizard community and what implications this has for the future management of the Island. Three species of lizard occur on Motunau Island; the common gecko (Hoplodactylus maculatus), common skink (Oligosoma nigriplantare polychroma) and spotted skink (O. lineoocellatum). Rabbits (Oryctolagus cuniculus) were present on the island from 1862 until their eradication in 1962. Since then, vegetation on the island has changed from being tussock-dominated to being dominated by exotic weeds. Data from lizard pitfall trap surveys carried out in 1967-75 by Tony Whitaker of the Department of Scientific and Industrial Research (DSIR) were compared with new pitfall trapping data to determine if changes in the lizard population had occurred in response to these vegetation changes. The abundance of O. n. polychroma and H. maculatus does not appear to change significantly. The distribution of these two species were significantly correlated but neither showed any preference for a particular type. The abundance of O. lineoocellatum was significantly greater in 1996/97 than in the earlier DSlR surveys. This could be a result of the vegetation becoming more open and more structurally complex since the early surveys. This would offer greater opportunities for O. lineoocellatum (which is strongly heliothermic) to thermoregulate and forage. O. lineoocellatum showed no consistent significant preference towards any habitat type, although they tended to be found more in 'margin' habitat. Research into pitfall trapping and the way lizard behaviour may influence pitfall trapping data needs to be undertaken as there is a possible trap bias in this study. Management of Motunau Island needs to ensure that a structurally complex environment is maintained to ensure high numbers of all three lizard species can continue to coexist.
40

Adding to nature : can artificial retreats be used to monitor and restore lizard populations?

Lettink, Marieke, n/a January 2008 (has links)
Artificial retreats are increasingly used to sample animal populations and in attempts to boost animal numbers in degraded habitats. Here, I test potential applications of artificial retreats for lizards inhabiting a coastal environment of high conservation value (Kaitorete Spit, New Zealand). I first conducted a pitfall-trapping survey examining the distribution and relative abundance of lizards in duneland, farmland and shrubland habitats, and tested the influence of trap placement on capture rates. Capture rates of the diurnal skinks Oligosoma maccanni (McCann�s skink) and O. nigriplantare polychroma (common skink) were highest in duneland and farmland, respectively, and were most sensitive to the distance separating traps from the nearest cover (the greater the distance, the lower the capture rate). Captures of O. lineoocellatum (spotted skink) and Hoplodactylus maculatus (common gecko) were rare. Secondly, in separate chapters I test the utility of artificial retreats for monitoring: 1) a preference trial examining relative use of three types of artificial retreats by skinks (O. maccanni and O. n. polychroma) and geckos (H. maculatus); 2) a comparison of the effectiveness of artificial retreats relative to pitfall traps for detecting cryptic and primarily nocturnal geckos (H. maculatus) following translocation; and 3) capture-recapture estimation of population parameters (survival and abundance) of H. maculatus. I found that: 1) geckos strongly preferred retreats made of Onduline over corrugated iron and concrete tiles, whereas skinks exhibited no apparent preferences; 2) artificial retreats were more effective than pitfall traps for detecting geckos following translocation; and 3) monthly survival and recapture probabilities of geckos varied with age-class and over time. Estimated survival was unexpectedly low, possibly due to excessive trap spacing. I developed a new capture-recapture model specifically for population size estimation with data from artificial retreats, which gave estimates that were up to 50% greater than those predicted by conventional capture-recapture models. I caution that permanent placement of artificial retreats in long-term studies may be inappropriate for estimation of population parameters due to potential habitat-enhancement effects and/or altered predation risk. Thirdly, I conducted a capture-recapture field experiment, using a replicated Before-After-Control-impact (BACI) design, to test the relative effects of habitat manipulation (artificial retreat addition) and partial predator removal (by fencing) on annual survival of duneland skink (O. maccanni) populations. Survival increased at sites with predator exclosures, but not at control sites or following the addition of artificial retreats, either alone or in combination with a predator exclosure. The magnitude of the increase in survival for the exclosure-only treatment was small, but sufficient to change the trajectory of an apparently stable population into an increasing one, suggesting that the population is limited by predators. Predator control, but not the addition of artificial retreats, is predicted to benefit O. maccanni. To conclude, the Onduline design developed here appears to be particularly useful for sampling cryptic, terrestrial geckos; however, artificial retreats must be used appropriately to avoid bias arising from habitat-enhancing effects and/or altered predation risk. The restoration value of artificial retreats requires further testing on other species and in areas where natural retreat sites are limited.

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