Maria Cristina Esposito

Quantifying the biodiversity value of tropical primary, secondary, and plantation forests

Biodiversity loss from deforestation may be partly offset by the expansion of secondary forests and plantation forestry in the tropics. However, our current knowledge of the value of these habitats for biodiversity conservation is limited to very few taxa, and many studies are severely confounded by methodological shortcomings. We examined the conservation value of tropical primary, secondary, and plantation forests for 15 taxonomic groups using a robust and replicated sample design that minimized edge effects. Different taxa varied markedly in their response to patterns of land use in terms of species richness and the percentage of species restricted to primary forest (varying from 5% to 57%), yet almost all between-forest comparisons showed marked differences in community structure and composition. Cross-taxon congruence in response patterns was very weak when evaluated using abundance or species richness data, but much stronger when using metrics based upon community similarity. Our results show that, whereas the biodiversity indicator group concept may hold some validity for several taxa that are frequently sampled (such as birds and fruit-feeding butterflies), it fails for those exhibiting highly idiosyncratic responses to tropical land-use change (including highly vagile species groups such as bats and orchid bees), highlighting the problems associated with quantifying the biodiversity value of anthropogenic habitats. Finally, although we show that areas of native regeneration and exotic tree plantations can provide complementary conservation services, we also provide clear empirical evidence demonstrating the irreplaceable value of primary forests.

Historical ecology of Amazonian lizards : implications for community ecology

Nineteen species of lizards simultaneously studied at the Curua-Una in the central Amazon of Brazil separate on the basis of microhabitat use and prey types. There is no relationship between microhabitat niche breadths and dietary niche breadths, species using the greatest diversity of microhabitats do not necessarily use the greatest diversity of prey types. A pseudocommunity analysis revealed that the lizard assemblage is structured with respect to microhabitat and diets. A comparison of dietary overlaps with phylogenetic similarities indicates that much of the variation in dietary similarity in this assemblage is associated with phylogenetic similarity. A similar analysis with microhabitat overlaps yielded no relationship to phylogenetic similarity. These results suggest that much of the structure in this particular assemblage is historical, i.e., not the direct result of ongoing species interactions at the local level. Because this assemblage is comprised of lizards from a diversity of higher taxa (families), we suggest that historical factors may be more important in determining structure in phylogenetically deeply rooted assemblages than in phylogenetically shallow-rooted assemblages.

Niche segregation among sympatric Amazonian teiid lizards

Abstract We examined standard niche axes (time, place, and food) for three sympatric teiid lizards in the Amazon rain forest. Activity times during the day were similar among species. Ameiva ameiva were in more open microhabitats and had higher body temperatures compared with the two species of Kentropyx. Microhabitat overlaps were low and not significantly different from simulations based on Monte Carlo analysis. Grasshoppers, crickets, and spiders were important in the diets of all three species and many relatively abundant prey were infrequently eaten (e.g., ants). Dietary overlaps were most similar between the two species of Kentropyx even though microhabitat overlaps were relatively low. A Monte Carlo analysis on prey types revealed that dietary overlaps were higher at all ranks than simulated overlaps indicating that use of prey is not random. Although prey size was correlated with lizard body size, there were no species differences in adjusted prey size. A. ameiva ate more prey items at a given body size than either species of Kentropyx. Body size varies among species, with A. ameiva being the largest and K. altamazonica the smallest. The two species of Kentropyx are most distant morphologically, with A. ameiva intermediate. The most distant species morphologically are the most similar in terms of prey types. A morphological analysis including 15 species from four genera revealed patterns of covariation that reflected phylogenetic affinities (i.e., taxonomic patterns are evident). A cluster analysis revealed that A. ameiva, K. pelviceps, and K. altamazonica were in the same morphological group and that within that group, A. ameiva differed from the rest of the species. In addition, K. pelviceps and K. altamazonica were distinguishable from other species of Kentropyx based on morphology.

Comparative Ecology of Sympatric Gonatodes (Squamata: Gekkonidae) in the Western Amazon of Brazil

Abstract Two sphaerodactyline geckos, Gonatodes hasemani and G. humeralis were studied in eastern Rondônia, Brazil, to determine ecological factors allowing coexistence. Gonatodes hasemani lives primarily on fallen logs in undisturbed forest, whereas G. humeralis lives primarily on tree trunks. Although both species occur in most forest patches, G. hasemani is more common within terra firme (never flooded) forest, and G. humeralis is more common in forest adjacent to rivers. Gonatodes hasemani is slightly larger in body size and is more robust than the more arboreal G. humeralis. Both species are active at the same time during the day, maintain the same body temperatures, and are most frequently found in shade. Dietary overlaps based on numbers (0.831) and volumes (0.877) of prey types were high indicating relatively similar diets. Differences in prey types appear to reflect differences in microhabitat use, and both species eat prey of the same size. Reproductive characteristics are similar but the larger bodied G. hasemani produces slightly larger eggs. The niche axis on which these two lizards most clearly separate is microhabitat: G. hasemani uses lower perches with larger diameters in the forest primarily because individuals typically are found on fallen logs, whereas G. humeralis uses higher and thinner perches because individuals are typically found on tree trunks and vines. Limited data on snakes that prey on small lizards in Amazon forest suggests the possibility that niche differences between these Gonatodes species may be mediated by predators. Dois lagartos geconídeos Sphaerodactylinae, Gonatodes hasemani e G. humeralis, foram estudados no leste de Rondônia, Brasil, com o intuito de se determinar os fatores ecológicos que permitem sua coexistência. Gonatodes hasemani vive primariamente sobre troncos de árvores caídos, em mata não perturbada, enquanto G. humeralis vive primariamente sobre troncos em pé. Embora ambas as espécies ocorram na maioria das áreas de mata, G. hasemani é mais comum em mata de terra firme, enquanto G. humeralis é mais comum em matas adjacentes a rios. Gonatodes hasemani é ligeiramente maior quanto ao tamanho do corpo e mais robusto que seu congênere mais arborícola, G. humeralis. Ambas as espécies estão ativas nas mesmas horas do dia, mantêm a mesma temperatura corporal, e são mais frequentemente encontradas na sombra. Uma grande sobreposição na dieta, tanto baseada em número (0.831) quanto em volume (0.877) de tipos de presas indica dietas relativamente similares. As diferenças observadas nos tipos de presas parecem refletir diferenças no uso de microhabitats, sendo o tamanho das presas semelhantes para as duas espécies. As características reprodutivas são semelhantes, mas G. hasemani, que possui um corpo maior, produz ovos ligeiramente maiores. O eixo no qual esses dois lagartos mais claramente se separam, no que diz respeito ao nicho, é o microhabitat: G. hasemani utiliza substratos mais baixos e de maior diâmetro na mata, primariamente porque indivíduos são tipicamente encontrados em troncos caídos, ao passo que G. humeralis utiliza substratos mais altos e mais finos, já que indivíduos são encontrados tipicamente sobre troncos de árvores vivas e cipós. Os dados, ainda que limitados, sobre cobras que se alimentam de pequenos lagartos na floresta amazônica sugerem a possibilidade de que as diferenças de nicho entre essas duas espécies de Gonatodes possam ser mediadas por predadores.

Life in Shade: The Ecology of Anolis trachyderma (Squamata: Polychrotidae) in Amazonian Ecuador and Brazil, with Comparisons to Ecologically Similar Anoles

Abstract The Amazonian lizard Anolis trachyderma was studied at three sites stretching from eastern Ecuador to the central Amazon of Brazil. These lizards occupy low vegetation and leaf litter microhabitats in well-shaded, damp rain forest. Their body temperatures are low (27.8 C on average) and only slightly higher than corresponding substrate and air. They are as likely to be active on cloudy as on sunny days but are usually found in shade. The diet is varied, but dominated volumetrically by grasshoppers-crickets, insect larvae-eggs-pupae, spiders, roaches, and lizard shed skin. Although dietary overlaps among populations are low, no significant differences in prey choice existed based on a randomization analysis. Locality-based and sexual variation in morphology was evident. Overall, A. trachyderma appears similar ecologically across a large portion of the Amazon. Comparisons with three ecologically similar anoles, Anolis nitens scypheus (sympatric with A. trachyderma) and Anolis humilis (no range overlap), reveal similar microhabitat use, body temperatures, and diets, but substantially different morphology. The ecomorph concept may not apply as well to mainland anoles as to island ones, possibly because taxonomically distant lizard species may have had a stronger historical effect on mainland anoles than on island species.

SMALL IN A BIG WORLD: ECOLOGY OF LEAF-LITTER GECKOS IN NEW WORLD TROPICAL FORESTS

Abstract We studied the ecology of four species of closely related leaf litter geckos, Coleodactylus amazonicus, C. septentrionalis, Lepidoblepharis xanthostigma, and Pseudogonatodes guianensis in tropical rainforests of Brazil and Nicaragua. All are found in leaf litter of undisturbed tropical forest where mean hourly surface temperatures vary from 23.5–29.1 C. Surface temperatures, where individual C. amazonicus were found, averaged 27.4 C and air averaged 29.9 C. Coleodactylus amazonicus was the smallest species and L. xanthostigma was the largest. The latter was the most different morphologically as well. Tail loss rates varied from 45.5–81.8% among species. All four species ate very small prey items, largely springtails, homopterans, termites, small insect larvae, and spiders. Nevertheless, considerable differences existed among species. Some variation existed among populations of C. amazonicus. Prey size was correlated with lizard SVL within and among species. All four species are typically the smallest species in their respective lizard assemblages. Small body size may have consequences for predation. Partially due to small body size, these lizards are vulnerable to extirpation resulting from effects of tree removal on thermal attributes of their leaf litter environment.

Life on the Leaf Litter: The Ecology of Anolis nitens tandai in the Brazilian Amazon

Abstract We studied the ecology of Anolis nitens tandai at three localities in the central and western Amazon of Brazil. The lizards were largely restricted to leaf litter microhabitats in relatively undisturbed rain forest. Activity occurred throughout the day. Body temperatures of active lizards averaged 27.7 ± 0.3 C and were similar to air and substratum temperatures in the microhabitats in which lizards were found. Microhabitats containing lizards were slightly warmer than a random set of microhabitats suggesting that the lizards selected relatively warm sites within a relatively cool forest habitat, but avoidance of treefalls suggests lizards do not seek out the warmest available microhabitats. The diet consisted mostly of grasshoppers, crickets, spiders, and insect larvae. Mean prey size increased with lizard body size, and lizards varied in how full their stomachs were. Sexual dimorphism in mass and limb length exists. Compared with other subspecies of Anolis nitens, A. n. tandai has relatively longer limbs than Anolis nitens scypheus or Anolis nitens nitens and intermediate body temperatures. Estudou-se a ecologia de Anolis nitens tandai em três localidades da Amazônia brasileira central e ocidental. Os referidos lagartos foram encontrados principalmente em microhabitats do folhiço, em floresta úmida relativamente não perturbada. Apresentaram-se ativos durante todo o dia, com uma temperatura corporal média de 27,7 ± 0,3 C, similar às temperaturas do ar e do substrato no microhabitat onde se encontravam. As temperaturas nos microhabitats contendo lagartos mostrou-se ligeiramente mais elevada que a de uma amostra aleatória de microhabitats, sugerindo que os lagartos procuram locais relativamente quentes em meio a um habitat florestal relativamente frio. Contudo, o fato de que evitam clareiras causadas pela queda de árvores sugere que eles não procuram os microhabitats mais quentes disponíveis. Dimorfismo sexual quanto à massa corporal e comprimento dos membros locomotores existe. A dieta consistiu principalmente de gafanhotos, grilos, aranhas e larvas de insetos. O tamanho médio da presa aumentou com o tamanho do corpo do lagarto, e os lagartos variaram com relação à quantidade de alimento encontrada nos estômagos. Em comparação a outras subespécies de Anolis nitens, A. n. tandai apresenta membros locomotores relativamente mais longos que Anolis nitens scypheus ou Anolis nitens nitens, e temperaturas corporais intermediárias.

Social wasps and bees captured in carrion traps in a rainforest in Brazil

Information is presented on social wasps and bees caught in carrion traps in ‘terra firme’ rainforest in Caxiuanã, PA, Brazil. Six species of epiponine wasps were captured. Angiopolybia pallens was the most frequent species, being caught in approximately 43.5% of the trials, followed by Angiopolybia paraensis (15.8%), Agelaia fulvofasciata (5.6%) and Agelaia angulata (3.3%). Agelaia pallipes and Agelaia cajennensis both had only a single individual captured. Twelve species of social bees were captured. The genera Trigona, Partamona and Melipona had similar numbers of species, but frequencies varied considerably. One individual of Apis mellifera was captured.

Sharing Amazonian Rain-Forest Trees: Ecology of Anolis punctatus and Anolis transversalis (Squamata: Polychrotidae)

Abstract We studied the ecology of Anolis punctatus and Anolis transversalis at six localities in the Amazon region of Ecuador and Brazil from 1994–1999. Both lizards are arboreal, about the same size (A. punctatus slightly larger) but differ in some body proportions. Anolis transversalis is restricted to undisturbed primary forest more so than A. punctatus, but both use similar microhabitats. During midday, A. transversalis was not observed, suggesting that individuals may not be active near the ground at that time. Both species are thermal conformers although each was able to maintain Tb slightly higher than that of its perch. Most lizards contained prey, and, overall, a positive relationship existed between lizard body size (SVL) and mean prey volume. Volumetrically, A. punctatus ate mostly ants and orthopterans, whereas A. transversalis ate mostly roaches, beetles, and ants. Dietary overlaps were low (0.56). These two species can be considered “crown giants” among Amazonian anoles. Similar to many Amazonian rain-forest lizards, ecological traits of A. punctatus and A. transversalis render them likely candidates for local extinction when deforestation occurs.

First record of Chrysomya rufifacies (Macquart) (Diptera, Calliphoridae) from Brazil

First record of Chrysomya rufifacies (Macquart) (Diptera, Calliphoridae) from Brazil. In addition to its native fauna, the Neotropical region is known to be inhabited by four introduced species of blow flies of the genus Chrysomya. Up until now, only three of these species have been recorded in Brazil - Chrysomya albiceps (Wiedemann), Chrysomya megacephala (Fabricius), and Chrysomya putoria (Wiedemann). In South America, C. rufifacies (Macquart) has only been reported from Argentina and Colombia. This study records C. rufifacies from Brazil for the first time. The specimens were collected in an area of cerrado (savanna-like vegetation) in the municipality of Caxias in state of Maranhao, and were attracted by pig carcasses.