- CBIO
INPA
CP 2223
69080-971 Manaus AM
Brazil - 55 92 36431834
William Magnusson
Instituto Nacional de Pesquisas da Amazônia, CBIO, Faculty Member
The high diversity of amphibians in rhe central Amawn Rain Forest alIowed us to exarnine rhe inHuence of tadpole antipredator defenses on assemblage structure and composition wirhin bodies of water (a diversity) and among aquatic sites (~... more
The high diversity of amphibians in rhe central Amawn Rain Forest alIowed us to exarnine rhe inHuence of tadpole antipredator defenses on assemblage structure and composition wirhin bodies of water (a diversity) and among aquatic sites (~ diversity) at a local scale. During a rhree-year stUdy of tadpole assemblage composition, we found rhat rhe anuran community used a variety ofbodies of water for reproduction; rhese ranged from streams and streamside ponds to isolated forest ponds. The distribution of several tadpole species was negatively related to fish density. while orher species coexisted wirh high densities of fish. Tadpole size did not ensure survival against fish, and few tadpoles avoided fish by hiding in rhe leaf litter. Controlled predation experiments using a single tadpole species in a no-choice situation were conducted over 24-to 48-hour periods. Nearly alI species of tadpoles rhat occurred in habitats wirh high fish densities were unpalatable to fish (except Centro/ene/Ja oyampimsis), indicating that unpalatability is a major adaptation alIowing tadpoles and fish to coexist in rhis system. Unpalatability (to fish). however, was not an effective antipredator defense against OOonate larvae, rhe orher major tadpole predator in rhis system. The combination of predation pressure and rhe anti-predator traits exhibited by individual species largely determined rhe composition of tadpole assemblages in individual bodies of water (a diversity). The heterogeneous distribution of predators among bodies water and rhe diversity of antipredator defenses exhibited by larval amphibians facilitated high diversity in rhis community (~ diversity). RESUMO A elevada diversidade de anflbios na floresta Amazônica central nos perrniriu examinar a influência das defesas anripre-dadores de girinos na esrrututa e na composição das comunidades nos corpos d'água (diversidade alfa) e enrre corpos d'água (diversidade beta) em uma escala local. Durante um estudo de três anos da composição da comunidade de girinos nós enconrrarnos que a comunidade de anuros usa urna variedade de corpos d'água para a reprodução; estes variaram de córregos e de poças ao lado de córregos a poças isoladas na floresta. A distribuição de várias espécies de girinos estava negativamente relacionada à densidade de peixes enquanto ourras espécies coexisriram com elevadas densidades de peixes. O tamanho do girino não assegurou a sobrevivência no encontro com peixes, e poucos girinos evitaram os peixes abrigando-se na camada de folhiço. Experiências controladas de predação utilizando uma única espécie de girino em uma situação sem-escolha foram conduzidas dUtante perlodos de 24-48 hotas. Quase todas as espécies de girinos que ocorreram em habitats com elevadas densidades de peixes eram impalatáveis para peixes (exceto Centrolenella oyampiensis), indicando que a impalatabilidade é a principal adaptação permitindo a coexixtência de girinos e peixes neste sistema. Enrretanto, a impalatabilidade (aos peixes) não foi uma defesa anripredador eficaz contra larvas de odonata, o outro principal predador de girinos neste sistema. A combinação da pressão de predação e das caracterlsticas anripredador exibidos por cada espécie individualmente determinou em grande parte a composição da comunidade de girinos em corpos d'água individuais (diversidade aifa). A distribuição heterogênea dos predadores enrre corpos d'água e a diversidade de defesas conrra pre-dadores exibidas por larvas de anflbios facilitou a elevada diversidade nesta comunidade (diversidade beta).
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Ferraz et al. (2008) indicated the need for planning in biological monitoring in the Amazon, and reviewed what they considered recent progress. The problems and solutions they discuss are well known, and it is unlikely that many... more
Ferraz et al. (2008) indicated the need for planning in biological monitoring in the Amazon, and reviewed what they considered recent progress. The problems and solutions they discuss are well known, and it is unlikely that many biologists would disagree with most of them. ...
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We present a synthesis of the first 10 years of Long Term Ecological Research project in Amazonian Forest. We elucidate the natural dynamics of forest ecosystem processes and associated biota, and its changes caused by distinct pressures... more
We present a synthesis of the first 10 years of Long Term Ecological Research project in Amazonian Forest. We elucidate the natural dynamics of forest ecosystem processes and associated biota, and its changes caused by distinct pressures of selective timber extraction and forest fragmentation. We found that, for both plants and animals, densities of individ- uals and distribution of species assemblages are spatially heterogeneous at the mesoscale, even in relatively undisturbed forests, and that associations with topo-edaphic variables allow prediction of a considerable part of this variation. For biological groups whose dynam- ics were studied in the short-term, levels of change in species composition and densities were relatively high, and these changes were generally in tune with spatial environmen- tal variation. The impact of selective logging on assemblages and ecosystem processes was normally moderate, and around 19 years were needed for recovering forest biomass and tree size distribution. Continued studies are needed to determine the time required for recuper- ation of timber stocks and pre-logging floristic composition. Selective logging appears to be compatible with the biodiversity conservation, but reduction and better planning of road access may be more important than planned logging intensities. Habitat-loss’ impact on organisms and ecosystem processes is large and long-lasting, since it induces the loss of many taxonomic groups and species, higher tree mortality and accelerated forest dynamics. There was a negative synergy between the impacts of habitat loss and climatic changes, and a better understanding of these processes can only be obtained through long-term research.
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Resumo O estudo dos padrões de movimento dos jacarés do Pantanal ocorreu em uma área de lagoas isolados e em uma área cortada por rios intermitentes no Pantanal. Foram marcados jacarés em 100 lagoas, na área de lagoas (1986-2001), e em 2... more
Resumo O estudo dos padrões de movimento dos jacarés do Pantanal ocorreu em uma área de lagoas isolados e em uma área cortada por rios intermitentes no Pantanal. Foram marcados jacarés em 100 lagoas, na área de lagoas (1986-2001), e em 2 rios, na área de rios (1987-1999). Foram recapturados 163 machos adultos, 132 fêmeas adultas e 237 jovens e monitorados 67 jacarés adultos por radiotelemetria nas duas áreas. No intervalo de 2 anos, a maioria dos jovens moveu-se apenas dentro da área de lagoas ou da de rios, numa distância máxima de 6,0 km (1,7± 0,9 km), na área de lagoas, e de 1,25 km (0,5± 0,3 km), na área de rios. Somente cinco jovens marcados nos lagos foram recapturados depois de um intervalo de 5 a 10 anos. Em 1 ano, fêmeas e machos com mais que 40 cm de comprimento rostro-cloacal (CRC) moveram-se em distâncias similares nas duas áreas (até 9,8 km). Fêmeas e machos maiores que 40 cm (CRC) foram registrados locomovendo-se por distâncias máximas de 16 a 18 km, respectivamente, e...
Aerial surveys were employed on study of environmental monitoring in Brazil by the first time in 1991. In this study an area of approximately 140.000 Km2 of the Pantanal Mato-Grossense was covered using a Cessna 206 aircraft, flying 60 m... more
Aerial surveys were employed on study of environmental monitoring in Brazil by the first time in 1991. In this study an area of approximately 140.000 Km2 of the Pantanal Mato-Grossense was covered using a Cessna 206 aircraft, flying 60 m above the ground with velocity of 200 km/h. 50 transects spaced six geographic minutes apart from each other (~11 km) were systematically sampled from east to west. The method applied consisted in sampling the habitat directly below of aircraft at intervals of 36 geographic seconds (~ 1 km), resulting in a total amount of 11.570 records for whole survey area, which represents a sampling intensity of 1,78%. Sixteen types of vegetation were identified, differentiated by sub regions and percent coverage of the survey area, and environmental impacts such as burning, deforestation, forage cultivation were registration. Based on the information generated through this methodology, estimates of area cultivated, area deforested, as well as an index of defore...
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Sampling ground-dwelling ants in the field is relatively fast, but sorting and identifying in the laboratory is costly and time-consuming. Using sub-samples collected in 25 km2 grids, we surveyed ant assemblages using sardine baits,... more
Sampling ground-dwelling ants in the field is relatively fast, but sorting and identifying in the laboratory is costly and time-consuming. Using sub-samples collected in 25 km2 grids, we surveyed ant assemblages using sardine baits, pitfall traps and Winkler extraction in three Amazonian vegetation types. Combining all three techniques detects the greatest number of species, but may be inefficient. Therefore, we compared the pooled results from the three techniques to results using one or two techniques combined. We evaluated whether the extra information acquired by adding a sampling technique compensates for the time and money associated with the extra processing. We also evaluated the consequences of the
reduced effort on the retention of ecological information captured by the three techniques, using soil clay content, terrain slope and altitude as predictor variables in an ecological analysis. Pitfall traps captured the largest number of species and had the highest congruence with ant assemblages recorded by other techniques. Redundancy analysis indicated that pitfall-trapping is the most efficient technique, allowing reduction of 48% in cost and 43% in time. The loss of information about species richness when using
only pitfall traps is apparently compensated by the saving of cost and time in the field and laboratory, because use of this technique alone was sufficient to detect all the responses of the ant assemblage to environmental variables that were detected by other techniques. These results indicate that considerable
gains in efficiency can be obtained in most Amazonian-forest monitoring programs for ants by using only pitfall traps.
reduced effort on the retention of ecological information captured by the three techniques, using soil clay content, terrain slope and altitude as predictor variables in an ecological analysis. Pitfall traps captured the largest number of species and had the highest congruence with ant assemblages recorded by other techniques. Redundancy analysis indicated that pitfall-trapping is the most efficient technique, allowing reduction of 48% in cost and 43% in time. The loss of information about species richness when using
only pitfall traps is apparently compensated by the saving of cost and time in the field and laboratory, because use of this technique alone was sufficient to detect all the responses of the ant assemblage to environmental variables that were detected by other techniques. These results indicate that considerable
gains in efficiency can be obtained in most Amazonian-forest monitoring programs for ants by using only pitfall traps.
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1. The use of spatial variables is a common procedure in ecological studies. The technique is based on the definition of a connectivity⁄distance matrix that conceptually defines the dispersal of organisms. The shortest distance between... more
1. The use of spatial variables is a common procedure in ecological studies. The technique is based on the definition of a connectivity⁄distance matrix that conceptually defines the dispersal of organisms. The shortest distance between two points is a straight line. Despite the fact that a straight line may not represent the easiest dispersal path for many kinds of organisms, straight-line distances are often used to detect patterns. We argue that other types of connectivity⁄distance matrices will better represent dispersal paths, such as the watercourse distance for aquatic organisms (e.g. fish, shrimps).
2. We used empirical and simulated community data to evaluate the usefulness of spatial variables generated from watercourse and overland (straight-line) distances.
3. Spatial variables based on watercourse distances captured patterns that straight-line distances did not, and provided better representations of the spatial patterns generated by dispersal along a dendritic network.
2. We used empirical and simulated community data to evaluate the usefulness of spatial variables generated from watercourse and overland (straight-line) distances.
3. Spatial variables based on watercourse distances captured patterns that straight-line distances did not, and provided better representations of the spatial patterns generated by dispersal along a dendritic network.
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Aerial surveys were employed on study of environmental monitoring in Brazil by the first time in 1991. In this study an area of approximately 140.000 Km2 of the Pantanal Mato-Grossense was covered using a Cessna 206 aircraft, flying 60 m... more
Aerial surveys were employed on study of environmental monitoring in Brazil by the first time in 1991. In this study an area of approximately 140.000 Km2 of the Pantanal Mato-Grossense was covered using a Cessna 206 aircraft, flying 60 m above the ground with velocity of 200 km/h. 50 transects spaced six geographic minutes apart from each other (~11 km) were systematically sampled from east to west. The method applied consisted in sampling the habitat directly below of aircraft at intervals of 36 geographic seconds (~ 1 km), resulting in a total amount of 11.570 records for whole survey area, which represents a sampling intensity of 1,78%. Sixteen types of vegetation were identified, differentiated by sub regions and percent coverage of the survey area, and environmental impacts such as burning, deforestation, forage cultivation were registration. Based on the information generated through this methodology, estimates of area cultivated, area deforested, as well as an index of defore...
The influence of rain in limnological characteristics of Viruá wetlands, Brazilian Amazon A influência da chuva nas características limnológicas das áreas alagáveis do Viruá, Amazônia brasileira Abstract: Aim: Floodplains occupy a vast... more
The influence of rain in limnological characteristics of Viruá wetlands, Brazilian Amazon A influência da chuva nas características limnológicas das áreas alagáveis do Viruá, Amazônia brasileira Abstract: Aim: Floodplains occupy a vast area of the Amazon basin but little is known of how their physical and limnological characteristics respond to local and regional ecological processes. In the Negro River basin and its main tributary, the Branco River, there are large areas that are seasonally flooded by water from local rainfall and that are not directly connected to major rivers. One such area is the floodplain of Viruá National Park, in Roraima state, northern Brazil. Methods: The physical and chemical limnological characteristics of 19 plots in this area were monitored over three years (2008-2010), with samples collected each year at the beginning and end of the rainy season (May to August). Results: The water bodies studied had low mean values for electrical conductivity (22.0 ± 14.0 µS*cm –1) and pH (4.8 ± 0.7), relatively high temperatures (26.6 ± 2.7 °C), and moderate values for dissolved oxygen saturation (43.0 ± 21.5%) and water transparency (87.9 ± 38.7 cm). There was no significant difference in the limnological characteristics of the aquatic plots between the beginning and end of the rainy seasons in 2008 and 2010, but there were significant differences in 2009 due to an atypical rainfall pattern with two short dry spells during the rainy season. Multivariate analysis showed that the highest temporal variations in the limnological characteristics of the aquatic plots resulted from changes in water transparency, and these changes were related to soil type, elevation of the plot, and the particular micro-basins to which they were connected. Conclusions: This dynamic is different from that of most floodplains in the Amazon region, where the limnological pattern is well-defined seasonally and strongly dependent on the direct connectivity to large river systems. Floodplains not connected to large rivers should receive special attention in relation to the expected impacts of global climate change because of their high dependence on local rainfall. Resumo: Objetivos: As planícies alagáveis da Amazônia ocupam uma vasta área e compreender os padrões das características limnológicas dessas planícies ee grande importância para os processos ecológicos locais e regionais. Na bacia do rio Negro e de seu principal afluente, o rio Branco, há grandes áreas sazonalmente alagadas que são abastecidas principalmente por chuvas locais e não são conectadas diretamente com grandes rios. Uma dessas áreas eá planície alagável do Parque Nacional do Viruá, em Roraima, no extremo norte do Brasil. Métodos: Foram monitoradas as características físicas e limnológicas de 19 parcelas durante três anos (2008 -2010), com coletas realizadas no início e no fim do período de chuvas (maio -agosto). Resultados: Os corpos d'água estudados apresentaram baixos valores médios de condutividade elétrica (22.0 ± 14,0 µS*cm –1) e pH (4.8 ± 0.7). A temperatura foi relativamente alta (26.6 ± 2.7 °C) e o oxigênio dissolvido teve valores moderados de saturação (43.0 ± 21.5%). A transparência da água apresentou grande oscilação espacial e temporal (87.9 ± 38.7 cm). Não houve diferenças significativas nas características limnológicas das parcelas aquáticas entre o início e o fim dos períodos chuvosos de 2008 e 2010, mas houveram em 2009 devido a um regime de chuvas atípico. Análises multivariadas evidenciaram que as maiores variações temporais nas 2014, vol. 26, no. 3, p. 254-267 255 The influence of rain in limnological... características limnológicas das parcelas aquáticas são resultantes de mudanças estocásticas da transparência da água, o que está relacionado com o tipo de solo, altitude das parcelas e com a microbacia à qual está conectada. Conclusões: Essa dinâmica eiferente da maioria dos ambientes de várzea da região, onde o padrão da dinâmica limnológica eortemente dependente de uma conexão direta com grandes sistemas fluviais. Planícies alagáveis não conectadas a grandes rios deveriam receber especial atenção em relação aos impactos esperados decorrentes das mudanças climáticas devido à sua grande dependência do regime de precipitação local. Palavras-chave: transparência da água, variação sazonal, área alagável, bacia do rio Branco, Parque Nacional do Viruá, poças temporárias.
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1. The effects of seasonal inundation on the biology of fishes on floodplains of large Amazonian rivers are well studied. However, the small seasonal changes in headwater streams are generally considered to have little effect on fish... more
1. The effects of seasonal inundation on the biology of fishes on floodplains of large Amazonian rivers are well studied. However, the small seasonal changes in headwater streams are generally considered to have little effect on fish assemblages.
2. Inthisstudy,weanalysedseasonalchangesinthespeciescompositionandabundanceof fish in small Amazonian forest streams. We sampled fish with hand and seine nets in headwater streams in a 10 000 ha terra-firme forest reserve near Manaus, Brazil. Each stream was surveyed at the end of the 2005 dry season, at the beginning of the 2006 rainy season and at the beginning of the 2006 dry season, by means of a standardized sampling effort.
3. The numbers of individuals and species caught were higher in the dry season, but rarefaction analyses indicated that greater species numbers could have been due simply to the larger number of individuals caught.
4. Between the dry and rainy season, the direction of changes in species composition in multivariate space varied among sites, especially for quantitative (abundance) data. However, the observed variation among sites was the less than expected if the directions of change were random.
5. Fish assemblages in the second dry season were more similar to those in the
previous dry season than expected if changes in species composition among seasons were random. This indicates that a general seasonal pattern in fish assemblages can be detected, despite the existence of some erratic site-specific changes.
6. Most of the species that showed large seasonal variations in density occupy temporary ponds during the rainy season, when much of the valley is inundated and pond networks form adjacent to streams. Short-duration lateral migrations to these ponds may play an important role in the seasonal fish-assemblage dynamics in Amazonian headwater streams.
7. Our results contrast with previous studies on small Amazonian streams, which have found little seasonal change in fish assemblages, and highlight the importance of the abundance of common species as an indicator of general fish assemblage structure in biological monitoring programmes.
2. Inthisstudy,weanalysedseasonalchangesinthespeciescompositionandabundanceof fish in small Amazonian forest streams. We sampled fish with hand and seine nets in headwater streams in a 10 000 ha terra-firme forest reserve near Manaus, Brazil. Each stream was surveyed at the end of the 2005 dry season, at the beginning of the 2006 rainy season and at the beginning of the 2006 dry season, by means of a standardized sampling effort.
3. The numbers of individuals and species caught were higher in the dry season, but rarefaction analyses indicated that greater species numbers could have been due simply to the larger number of individuals caught.
4. Between the dry and rainy season, the direction of changes in species composition in multivariate space varied among sites, especially for quantitative (abundance) data. However, the observed variation among sites was the less than expected if the directions of change were random.
5. Fish assemblages in the second dry season were more similar to those in the
previous dry season than expected if changes in species composition among seasons were random. This indicates that a general seasonal pattern in fish assemblages can be detected, despite the existence of some erratic site-specific changes.
6. Most of the species that showed large seasonal variations in density occupy temporary ponds during the rainy season, when much of the valley is inundated and pond networks form adjacent to streams. Short-duration lateral migrations to these ponds may play an important role in the seasonal fish-assemblage dynamics in Amazonian headwater streams.
7. Our results contrast with previous studies on small Amazonian streams, which have found little seasonal change in fish assemblages, and highlight the importance of the abundance of common species as an indicator of general fish assemblage structure in biological monitoring programmes.
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The workshop began with historical information about the work in Guatemala with crocodiles, undoubtedly standing out was the fi rst record of the species (type specimen) in 1851, and also highlighting other papers dealing with aspects of,... more
The workshop began with historical information about the work in Guatemala with crocodiles, undoubtedly standing out was the fi rst record of the species (type specimen) in 1851, and also highlighting other papers dealing with aspects of, from which could be obtained a basis for the proposed sampling in the country, through application of the four basic methods of habitat assessment and monitoring, night detection, marking and recapture of individuals, and location and monitoring of nests. It is worth noting the presence of relevant authorities in environmental issues in Guatemala, through Francisco Castañeda Moya (CECON Director), Dr. Hiram Ordoñez Chocano (CITES Scientifi c Authority and Wildlife Director for Guatemala) and Julio Madrid-Montenegro (Department of Wildlife, Peten Region VIII, CONAP), and representatives of Mexico, through two of the four coordinators of Mexico COPAN (Jerónimo Domínguez Laso and Marco Lopez Luna, Coordinators of Regions 3 and 2 respectively, COPAN Pr...