quinta-feira, 9 de agosto de 2012
Curso: Biologia, ecologia e conservação do boto-da-tainha (Tursiops truncatus)
Estão abertas as inscrições para o I Curso Teórico-Prático de Biologia, Ecologia e Conservação do Boto-da-Tainha (Tursiops truncatus), a se realizar nos dias 25 e 26 de agosto de 2012 na praia de Garopaba, Santa Catarina. Inscrições pelo e-mail institutobaleiafranca@gmail.com ou pelos telefones (48) 9963.1122 e (48) 9682.5718.
sábado, 4 de agosto de 2012
Microtus population biology: demographic changes in fluctuating populations of M. ochrogaster and M. pennsylvanicus in southern Indiana
KREBS, C.J.; KELLER, B.L.; TAMATIN, R.H. 1969. Microtus population biology: demographic changes in fluctuating populations of M. ochrogaster and M. pennsylvanicus in southern Indiana. Ecology 50(4):587-607.
Abstract. Microtus pennsylvanicus and M. ochrogaster are sympatric in southern Indiana grasslands. From June 1965 to August 1967 four populations were live trapped, three of them in 0.8-hectare (2-acre) outdoor pens. Both species increased during 1965 and reached peak densities in summer 1966. Microtus ochrogaster declined abruptly that fall and remained low; M. pennsylanicus declined the following spring.
One of the fenced populations increased to a density about three times that of its unfenced control. By early fall 1966 it had nearly destroyed its food resources and then suffered a severe decline associated with obvious overgrazing and starvation. No such overgrazing has been seen on any unfenced grasslands in this area. Dispersal is probably necessary for normal population regulation in these voles, since fenced populations seem unable to regulate their density below the limit set by starvation.
Both species bred extensively in the winter of 1965-66 during the phase of population increase. There was little or no breeding during the winter after the peak.
Survival of females in the trappable population of both species was high and relatively constant until the end of the cycle. In males, periods of low survival punctuated the increase and peak phases, and these periods of low male survival did not occur at the same time in the two Microtus species. Some mortality processes are thus higly specific for sex and species. In the fenced populations survival rates were very high and no sporadic male losses occurred.
Increasing and peak populations of M. pennsylvanicus and M. ochrogaster are characterized by adults of large body size. During the increase and peak phases some voles stopped growing at low weights (30-40 g) while others reached high aymptotic weights (45-55 g).
The demography of these Microtus species in southern Indiana is similar to that of other cyclic voles and lemmings in temperate and arctic areas.
Abstract. Microtus pennsylvanicus and M. ochrogaster are sympatric in southern Indiana grasslands. From June 1965 to August 1967 four populations were live trapped, three of them in 0.8-hectare (2-acre) outdoor pens. Both species increased during 1965 and reached peak densities in summer 1966. Microtus ochrogaster declined abruptly that fall and remained low; M. pennsylanicus declined the following spring.
One of the fenced populations increased to a density about three times that of its unfenced control. By early fall 1966 it had nearly destroyed its food resources and then suffered a severe decline associated with obvious overgrazing and starvation. No such overgrazing has been seen on any unfenced grasslands in this area. Dispersal is probably necessary for normal population regulation in these voles, since fenced populations seem unable to regulate their density below the limit set by starvation.
Both species bred extensively in the winter of 1965-66 during the phase of population increase. There was little or no breeding during the winter after the peak.
Survival of females in the trappable population of both species was high and relatively constant until the end of the cycle. In males, periods of low survival punctuated the increase and peak phases, and these periods of low male survival did not occur at the same time in the two Microtus species. Some mortality processes are thus higly specific for sex and species. In the fenced populations survival rates were very high and no sporadic male losses occurred.
Increasing and peak populations of M. pennsylvanicus and M. ochrogaster are characterized by adults of large body size. During the increase and peak phases some voles stopped growing at low weights (30-40 g) while others reached high aymptotic weights (45-55 g).
The demography of these Microtus species in southern Indiana is similar to that of other cyclic voles and lemmings in temperate and arctic areas.
quarta-feira, 1 de agosto de 2012
Mamíferos: da Terra aos Mares
A equipe do Laboratório de Ecologia de Mamíferos da Unisinos têm o prazer de convidar todos a participar da oficina Mamíferos: da Terra aos Mares.
A oficina visa apresentar o grupo dos mamíferos com aspectos de sua evolução, diversidade, ecologia, manejo, conservação e relações com o homem. A oficina ocorrerá nos dias 24 e 25 de agosto, e 1º de setembro de 2012, na Unisinos (Univerdade do Vale do Rio dos Sinos), em São Leopoldo, RS. As inscrições podem ser realizadas diretamente pela internet através do link: http://www.unisinos.br/extensao/eventos/EX120309/EX120309-00001/620/apresentacao.
DATAS: 24 e 25 de agosto, e 1º de setembro de 2012.
INVESTIMENTO: R$ 100,00.
INFORMAÇÕES: www.unisinos.br/eventos (eventos saúde).
CONTEÚDO PROGRAMÁTICO PREVISTO
A oficina será dividida em quatro módulos, sendo o primeiro módulo uma apresentação geral sobre características, diversidade e evolução dos mamíferos. Os quatro módulos seguintes apresentarão aspectos gerais e ecológicos sobre os mamíferos terrestres, e os quatro módulos seguintes apresentarão técnicas de estudo e monitoramento de populações de mamíferos marinhos, bem como suas interações com o homem.
O conteúdo detalhado previsto (sujeito a modificações) segue abaixo:
24/ago/2012
- Introdução geral: mamíferos, da terra aos mares (Msc Paulo T. Sarti, Fernando R.V. Lopes).
A oficina visa apresentar o grupo dos mamíferos com aspectos de sua evolução, diversidade, ecologia, manejo, conservação e relações com o homem. A oficina ocorrerá nos dias 24 e 25 de agosto, e 1º de setembro de 2012, na Unisinos (Univerdade do Vale do Rio dos Sinos), em São Leopoldo, RS. As inscrições podem ser realizadas diretamente pela internet através do link: http://www.unisinos.br/extensao/eventos/EX120309/EX120309-00001/620/apresentacao.
DATAS: 24 e 25 de agosto, e 1º de setembro de 2012.
INVESTIMENTO: R$ 100,00.
INFORMAÇÕES: www.unisinos.br/eventos (eventos saúde).
CONTEÚDO PROGRAMÁTICO PREVISTO
A oficina será dividida em quatro módulos, sendo o primeiro módulo uma apresentação geral sobre características, diversidade e evolução dos mamíferos. Os quatro módulos seguintes apresentarão aspectos gerais e ecológicos sobre os mamíferos terrestres, e os quatro módulos seguintes apresentarão técnicas de estudo e monitoramento de populações de mamíferos marinhos, bem como suas interações com o homem.
O conteúdo detalhado previsto (sujeito a modificações) segue abaixo:
24/ago/2012
- Introdução geral: mamíferos, da terra aos mares (Msc Paulo T. Sarti, Fernando R.V. Lopes).
25/ago/2012
- Biologia e ecologia de pequenos mamíferos (Msc Maury S.L. Abreu).
- Padrões de microestrutura de pelos: identificando mamíferos (Nathalia S. Freitas).
- Mamíferos terrestres de médio e grande porte (Msc Paulo T. Sarti).
- O uso do habitat por mamíferos terrestres (Guilherme W. Schmitz).
01/set/2012
- Técnicas de estudo em mamíferos-marinhos: coleta, curadoria de coleção e estudos osteológicos (Biol. Ana Paula Costa).
- Técnicas de estudo em mamíferos-marinhos: monitoramento de populações (Biol. Rodrigo Machado, Biol. Ana Paula Costa, Fernando R.V. Lopes).
- Interações entre mamíferos aquáticos e a atividade pesqueira: da pesca cooperativa ao conflito (Biol. Rodrigo Machado).
- Dimensões humanas (Mônica Terra, Biol. Ana Carolina Pont).
sábado, 28 de julho de 2012
Ecological scale and habitat use
MORRIS, D.M. 1987. Ecological scale and habitat use. Ecology 68(2):362-369
Abstract. Population density can respond to habitat at different scales. If habitat selection occurs as a consequence of resource exploitation, the density of fine-grained consumers should reflect microhabitat variation. But if habitat use is controlled by a variety of selective pressured, it is no longer apparent whether density should respond to micro- or macrohabitat. These two alternatives can be tested simultaneously by multiple regression models where macrohabitat are represented by dummy variables. When the local densities of two Temperate Zone rodents were analyzed in this way, macrohabitat and temporal effects were consistent significant predictors of rodent density; microhabitat was not. This analysis suggests species whose patterns of resource and habitat use probably depart from classical interpretations of species coexistence. It is probably premature to assess the role of habitat selection in the structure of ecological systems until the results of further tests of habitat scaling are reported.
Abstract. Population density can respond to habitat at different scales. If habitat selection occurs as a consequence of resource exploitation, the density of fine-grained consumers should reflect microhabitat variation. But if habitat use is controlled by a variety of selective pressured, it is no longer apparent whether density should respond to micro- or macrohabitat. These two alternatives can be tested simultaneously by multiple regression models where macrohabitat are represented by dummy variables. When the local densities of two Temperate Zone rodents were analyzed in this way, macrohabitat and temporal effects were consistent significant predictors of rodent density; microhabitat was not. This analysis suggests species whose patterns of resource and habitat use probably depart from classical interpretations of species coexistence. It is probably premature to assess the role of habitat selection in the structure of ecological systems until the results of further tests of habitat scaling are reported.
sábado, 21 de julho de 2012
Pseudoreplication and the design of ecological field experiments
HULBERT, S.H. 1984. Pseudoreplication and the design of ecological field experiments. Ecological Monographs 54(2):187-211.
Abstract. Pseudoreplication is defined as the use of inferential statistics to test for treatment effects with data from experiments where either treatments are not replicated (though samples may be) or replicates are not statistically independent. In ANOVA terminology, it is the testing for treatment effects with and error term inappropriate to the hypothesis being considered. Scrutiny of 176 experimental studies published between 1960 and the present revealed that pseudoreplication occurred in 27% of them, or 48% of all such studies that applied inferential staticts. The incidence of pseudoreplication is especially high in studies of marine benthos and small mammals. The critical features of controlled experimentation are reviewed. Nondemonic intrusion is defined as the impingement of chance events on and experiment in progress. As a safeguard against both it and preexisting gradients, interspersion of treatments is argued to be an obligatory feature of good design. Especially in small experiments, adequate interspersion can sometimes be assumed only by dispensing with strict randomization procedures. Comprehension of this conflict between interspersion and randomization is aided by distinguishing pre-layout (or conventional) and layout-specific alpha (probability of tyme I error). Suggestions are offered to statisticians and editors of ecological journals as to how ecologists' understanding of experimental design and statistics might be improved.
Abstract. Pseudoreplication is defined as the use of inferential statistics to test for treatment effects with data from experiments where either treatments are not replicated (though samples may be) or replicates are not statistically independent. In ANOVA terminology, it is the testing for treatment effects with and error term inappropriate to the hypothesis being considered. Scrutiny of 176 experimental studies published between 1960 and the present revealed that pseudoreplication occurred in 27% of them, or 48% of all such studies that applied inferential staticts. The incidence of pseudoreplication is especially high in studies of marine benthos and small mammals. The critical features of controlled experimentation are reviewed. Nondemonic intrusion is defined as the impingement of chance events on and experiment in progress. As a safeguard against both it and preexisting gradients, interspersion of treatments is argued to be an obligatory feature of good design. Especially in small experiments, adequate interspersion can sometimes be assumed only by dispensing with strict randomization procedures. Comprehension of this conflict between interspersion and randomization is aided by distinguishing pre-layout (or conventional) and layout-specific alpha (probability of tyme I error). Suggestions are offered to statisticians and editors of ecological journals as to how ecologists' understanding of experimental design and statistics might be improved.
sábado, 14 de julho de 2012
Habitat fragmentation and movements of three small mammals (Sigmodon, Microtus, and Peromyscus)
DIFFENDORFER, J.E.; GAINES, M.S.; HOLT, R.D. 1995. Habitat fragmentation and movements of three small mammals (Sigmodon, Microtus, and Peromyscus). Ecology 76(3):827-839.
Abstract. We studied the effects of habitat fragmentation on the movements of cotton rats (Sigmodon hispidus), deer mice (Peromyscus maniculatus), and prairie voles (Microtus ochrogaster) living in a fragmented landscape using 7.7 yr (1984-1992) of mark-recapture data. The study area included three kinds of 0.5-ha blocks: single large patches (5000 m²), clusters of medium patches (288 m²), and clusters of small patches (32 m²). We tested three predictions regarding animal movements. First, animal should move longer distances as fragmentation increases. Second, the proportion of animals moving will decrease as fragmentation increases. Third, species will show more movement from putative sources to putative sinks. In support of our first two predictions, all species (except male cotton rats) moved farther, and lower proportions of animals moved, as fragmentation increased. In testing our third prediction, we found no trends, for all species, between patch size and the net number of animals a block either imported or exported, indicating source-sink dynamics were probably not occurring on our study site. Furthermore, animals of all species (except female deer mice) switched more frequently to blocks of larger patches. For prairie voles in the spring and deer mice in the summer, relative abundance among blocks predicted from a Markov matrix model of switching probabilities showed high congruence with the actual abundances, indicating movement and abundance were related. In both cotton rats and prairie voles but not in deer mice, more juveniles and nonreproductive animals switched between blocks than did adults or reproductive animals. Deer mice switched more frequently than did either cotton rats or prairie voles; the latter species switched in similar frequencies. We discuss the implications of our data for modeling and conservation.
Abstract. We studied the effects of habitat fragmentation on the movements of cotton rats (Sigmodon hispidus), deer mice (Peromyscus maniculatus), and prairie voles (Microtus ochrogaster) living in a fragmented landscape using 7.7 yr (1984-1992) of mark-recapture data. The study area included three kinds of 0.5-ha blocks: single large patches (5000 m²), clusters of medium patches (288 m²), and clusters of small patches (32 m²). We tested three predictions regarding animal movements. First, animal should move longer distances as fragmentation increases. Second, the proportion of animals moving will decrease as fragmentation increases. Third, species will show more movement from putative sources to putative sinks. In support of our first two predictions, all species (except male cotton rats) moved farther, and lower proportions of animals moved, as fragmentation increased. In testing our third prediction, we found no trends, for all species, between patch size and the net number of animals a block either imported or exported, indicating source-sink dynamics were probably not occurring on our study site. Furthermore, animals of all species (except female deer mice) switched more frequently to blocks of larger patches. For prairie voles in the spring and deer mice in the summer, relative abundance among blocks predicted from a Markov matrix model of switching probabilities showed high congruence with the actual abundances, indicating movement and abundance were related. In both cotton rats and prairie voles but not in deer mice, more juveniles and nonreproductive animals switched between blocks than did adults or reproductive animals. Deer mice switched more frequently than did either cotton rats or prairie voles; the latter species switched in similar frequencies. We discuss the implications of our data for modeling and conservation.
Assinar:
Postagens (Atom)