ABSTRACT Frugivores and zoocoric trees represent an important proportion of tropical rainforest biodiversity. As niche differences favor species coexistence, we aimed to evaluate morphological and ...temporal niche segregation mechanisms among zoochoric trees and canopy frugivores in a tropical rainforest in the northeastern extreme of the Brazilian Amazon. We tested the effects of fruit morphology, tree size, frugivore body size and time of day on fruit consumption. We recorded the frugivore species that fed on 72 trees (44 species, 22 genera) and whether these frugivores swallowed the seeds. We monitored trees only once from 07:00 to 17:00 h between January and September 2017. We observed fruit consumption in 20 of the 72 trees. Seventy-three frugivore individuals from 22 species visited the trees. Heavier fruits were consumed by larger frugivores, while seed size was inversely correlated with frugivore size. Narrower fruits and fruits with smaller seeds had greater probability of having their seeds ingested, and larger frugivores were more prone to ingest seeds. Trees bearing fruits with smaller seeds were visited by a greater number of frugivores. Taxonomic groups differed in the time of arrival at fruiting trees. None of the evaluated variables (fruit weight and size, and seed size) affected the richness of frugivores that visited the trees. We concluded that, in the studied forest, fruit morphology (weight, size and seed size) is a niche segregation mechanism among zoochoric trees, while body size and time of day are niche segregation mechanisms among frugivores.
RESUMO Frugívoros e árvores zoocóricas representam uma proporção relevante da biodiversidade de florestas tropicais. Uma vez que a diferenciação de nicho favorece a coexistência das espécies, nós objetivamos investigar mecanismos morfológicos e temporais de segregação de nicho entre árvores zoocóricas e frugívoros de copa em uma floresta tropical no extremo nordeste da Amazônia brasileira. Testamos os efeitos da morfologia dos frutos, tamanho das árvores, tamanho corporal dos frugívoros e hora do dia sobre o consumo de frutos. Registramos as espécies de frugívoros que se alimentaram em 72 árvores (pertencentes a 44 espécies e 22 gêneros) e se esses frugívoros ingeriam sementes. Monitoramos cada árvore apenas uma vez, de 07:00 a 17:00 h, entre janeiro e setembro de 2017 e observamos o consumo de frutos em 20 das 72 árvores. Setenta e três indivíduos de frugívoros, pertencentes a 22 espécies, visitaram as árvores. Frutos mais pesados foram consumidos por frugívoros maiores, enquanto o tamanho das sementes foi inversamente correlacionado ao tamanho dos frugívoros. Frutos menores e com sementes menores tiveram uma maior probabilidade de ter suas sementes ingeridas, e frugívoros maiores apresentaram maior tendência a ingerir as sementes. Árvores com frutos com sementes menores foram visitadas por um maior número de indivíduos de frugívoros. Os grupos taxonômicos de frugívoros diferiram no tempo de chegada às árvores. Nenhuma das variáveis analisadas (peso e tamanho dos frutos e tamanho das sementes) afetou a riqueza de frugívoros que visitaram as árvores. Concluímos que, na floresta estudada, a morfologia dos frutos (tamanho, peso e tamanho das sementes) é um mecanismo de segregação entre árvores zoocóricas, enquanto tamanho corporal e horário do dia são mecanismos de segregação entre frugívoros.
Bactrocera carambolae is a quarantine pest present in Brazil and today represents the main phytosanitary barrier to the export of the fresh fruits produced in the country. The effect of soil classes ...and moisture on the pupation depth and pupal viability of this insect was evaluated. Soils with three textural classes (sandy, sandy clay loam and clay loam) and four moisture levels (0%, 30%, 60% and 90% of field capacity of each soil) were used, for a total of 12 treatments with six repetitions. The pupation depths varied from the surface to 5 cm. The soil class was the most significant variable regarding the pupal development of B. carambolae. The moisture level did not have a significant effect on the pupation depth or pupal emergence, but there was a strong effect of the interaction of soil texture and moisture on the pupal viability, with an increase in emergence with higher moisture in the clay loam and sandy clay loam soils.
Tropical non‐self‐supporting plants such as hemiepiphytes and nomadic vines are model organisms for disentangling biotic and environmental correlates which influence their occupancy patterns. We ...inventoried >4000 individuals from >3000 trees ranging from 1 to 200 cm diameter at breast height (DBH) in a northeastern Amazonian upland forest to address how tree (phorophyte) size, edaphic factors and recruitment strategy influence occupancy, diversity, and compositional patterns of two vascular non‐self‐supporting plant functional groups. Hemiepiphytes germinate on phorophytes prior to establishing soil connections, whereas nomadic vines initiate their life cycle on the forest floor and subsequently climb phorophytes for crown access, abandoning roots replaced by adventitious connections which may reach the ground. Our results show that larger phorophytes (≥30 cm DBH) supported more species for both hemiepiphytes and nomadic vines. However, nomadic vines' occupancy probabilities saturated faster at smaller stem sizes than that of hemiepiphytes indicating differential preferences for stem sizes among the two functional groups. For smaller phorophytes (<30 cm DBH), soil correlations were stronger with nomadic vines than hemiepiphytes, whereas no significant differences were detected among functional groups in relation to edaphic factors for larger (≥ 30 cm DBH) ones. Finally, a small core group of species showed disproportionately greater abundances among large phorophytes suggesting that autogenic processes differentially promote survivability. Such interactions among phorophyte size and edaphic factors may result from the contrasting ecological requirements of hemiepiphytes and nomadic vines at the recruitment stage, demonstrating the necessity for elaborate demographic‐based studies to better understand these complex plant–plant interactions.
in Spanish is available with online material
RESUMO
Las hemiepífitas y lianas nómades son plantas tropicales que no se sostienen a sí mismas y sirven como organismos modelo para desenredar las correlaciones bióticas y ambientales que influyen en sus patrones de ocupación. Inventariamos más de 4000 individuos en más de 3000 árboles que van desde 1 a 200 cm de diámetro a la altura del pecho (DAP) en un bosque de tierras altas en el noreste de la Amazonía para abordar cómo el tamaño del árbol (forófito), los factores edáficos y la estrategia de reclutamiento influyen en la ocupación, diversidad y patrones de composición de dos grupos funcionales de plantas vasculares no autosuficientes. Las hemiepífitas germinan en los forófitos antes de establecer conexiones con el suelo, mientras que las lianas nómades inician su ciclo de vida en el suelo del bosque y subsecuentemente trepan a los forófitos para acceder a la copa, abandonando las raíces reemplazadas por conexiones adventicias que pueden llegar al suelo. Nuestros resultados muestran que los forófitos más grandes (>30 cm DAP) soportaron más especies tanto para hemiepífitas como para lianas nómades. Sin embargo, las probabilidades de ocupación de las lianas nómadas se saturaron más rápido en tamaños de tallo más pequeños que las hemiepífitas, lo que indica preferencias diferenciales por los tamaños de tallo entre los dos grupos funcionales. Para los forófitos más pequeños (<30 cm DAP), las correlaciones del suelo fueron más fuertes con las lianas nómades que con las hemiepífitas, mientras que no se detectaron diferencias significativas entre los grupos funcionales en relación con los factores edáficos para los más grandes (> 30 cm DAP). Finalmente, un pequeño grupo central de especies mostró abundancias desproporcionadamente mayores entre los forófitos grandes, lo que sugiere que los procesos autógenos promueven la supervivencia de manera diferencial. Tales interacciones entre el tamaño de los forófitos y los factores edáficos pueden resultar de los requisitos ecológicos contrastantes de las hemiepífitas y las lianas nómades en la etapa de reclutamiento, lo que demuestra la necesidad de elaborar estudios demográficos para comprender mejor estas complejas interacciones planta‐planta.
Nomadic vines and hemiepiphytes are model organisms for disentangling biotic and environmental correlates which influence their occupancy patterns. Large trees (phorophytes) supported more species for both groups, but nomadic vines´ occupancy probabilities saturated faster at smaller stem sizes than that of hemiepiphytes indicating differential preferences for stem sizes. For smaller phorophytes, soil correlations were stronger with nomadic vines than hemiepiphytes, whereas no differences were found for larger phorophytes. A small core group of species showed disproportionately greater abundances among large phorophytes suggesting that autogenic processes differentially promote survivability.
Abstract
Comprehending the size distribution within a population and grasping its connection to tree maturation (onset of reproductive phase) is pivotal for formulating sustainable management ...strategies and conserving numerous tree species. The objective of this study was to compare the structure and probability of fruit production of
Carapa guianensis
in two types of forest (
varzea
, or floodplain, vs.
terra firme
, or upland) in the northeastern Amazon, Brazil. The study was conducted in four permanent plots of 300 × 300 m (two for each type of forest). All individuals ≥10 cm in diameter at breast height (DBH) were mapped and measured for DBH, height, and canopy characteristics (shape and position), and liana infestation. Sixty‐seven trees were inventoried in the upland forest and 297 in the floodplain forest. The trees were larger in the upland (33.36 ± 1.84 cm) than in the floodplain (21.92 ± 1.5 cm) and more than half (56%) of the upland trees and more than two thirds (67%) of floodplain trees were reproductive. The minimum diameter for fruit production in the floodplain (10.2 cm of DBH) was more than two times smaller than in the upland (25.5 cm of DBH). The probability of fruit production of a tree of the same size was twice as high in the floodplain compared with the upland, and trees with rounded canopies had a higher probability of fruit production in the upland. Our results showed that the probability of fruit production can be modeled with variables of tree size and canopy shape, and that intrinsic factors of the forests influence the reproductive maturity of
C. guianensis
which presents greater precocity and productive potential of seeds in the estuarine floodplain forest of the Amazon River.
Abstract in Portuguese is available with online material.
Resumo
Compreender a distribuição de tamanhos dentro de uma população e entender sua conexão com a maturação das árvores (início da fase reprodutiva) é fundamental para formular estratégias de manejo sustentável e conservar espécies de árvores. O objetivo do presente estudo foi comparar a estrutura e a probabilidade de produção de frutos de
Carapa guianensis
em dois tipos de floresta (várzea e de terra firme) no nordeste da Amazônia brasileira. O estudo foi realizado em quatro parcelas permanentes de 300 × 300 m (duas para cada tipo de floresta) no sul do estado do Amapá. Todos os indivíduos ≥10 cm de diâmetro a altura do peito (DAP) foram mapeadas e medidos quanto ao DAP, altura, características da copa (forma e posição) e infestação de lianas. Foram inventariadas 67 árvores na terra firme e 297 na várzea. As arvores foram maiores na terra firme (33.36 ± 1.84 cm) do que na várzea (21.92 ± 1.5 cm). Mais da metade (56%) das árvores da terra firme e mais de dois terços (67%) da várzea foram produtivas. O diâmetro mínimo para a produção de frutos na várzea (10.2 cm de DAP) foi mais de duas vezes menor do que na terra firme (25.5 cm de DAP). A probabilidade da produção de frutos de uma árvore de mesmo tamanho foi o dobro na várzea em comparação com a terra firme, e árvores com copas arredondadas tiverem maior probabilidade de produção de frutos na terra firme. Nossos resultados mostram que a probabilidade de produção de frutos pode ser modelada com variáveis de tamanho da árvore e forma de copa e que fatores intrínsecos das florestas influenciam na maturidade reprodutiva de
C. guianensis
, que apresenta maior precocidade e potencial produtivo de sementes na floresta de várzea.
This work aimed to assess the potential of Geissospermum argenteum Woodson (Apocynaceae) as a reservoir of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) in an upland forest in Brazil.
...The study was conducted in a remnant of primary upland forest, in which were distributed 10 plots (0.5 ha each). All individuals of G. argenteum with diameters greater than 5 cm at a height of 1.3 m were inventoried. Two trees per plot were selected to assess the total production of fruit. Collectors were installed under the canopy projection of each tree. The fruits were counted and weighed in the field and were transported to the laboratory, to determine the dry mass. Samples of fruits were collected to investigate their infestation by fruit flies and percentage of parasitism.
A total of 394 specimens of G. argenteum were identified in the 5 ha investigated area, of which only 126 produced fruits during the 12 months of the assessment. Production ranged from 59 to 2478 fruits per plant (0.59 and 19.73 kg of fresh mass, respectively). Fifty‐nine fruit samples were collected from 44 plants, from which 7703 puparia were obtained. Only Anastrepha atrigona Hendel emerged from the puparia. The mean infestation rate was 554.9 puparia/kg of fruit (0.4–1628.6 puparia/kg). Four species of parasitoids were obtained, with mean percentage of parasitism of 2.27% (0.23–9.01%).
Our results show that G. argenteum is a reservoir of fruit fly parasitoids, highlighting the importance of its conservation in native habitats, as well as its multiplication in areas close to commercial orchards.
► A small quantity of variation in tree mortality can be explained by soil and topography. ► Soil and topography can predict only mortality of small- and medium-sized trees. ► Climatic disturbances ...can increase the effect of soil and topography on tree mortality.
Tree mortality in Amazonia has been related to regional variation in soil, topography and climatic disturbances, but the magnitude of the effect of these factors on tree mortality at local and mesoscales remains poorly determined. We investigated tree mortality in 72 1-ha permanent plots spanning 64
km
2 of tropical moist forest in Reserva Ducke, Manaus, Brazil. Plots were censused three times (2000–2003, 2003–2005, and 2005–2008), resulting in two census intervals. The relationships of soil and topography to tree mortality were dependent on tree size. Small- and medium-sized trees (1
⩽
dbh
<
30
cm) had similar relationships of mortality with soil and topography, while large trees (dbh
⩾
30
cm) showed different (or no) relationships. The effects of soil and topography on tree mortality also varied temporally. In the second census interval after storms, soil and topography explained about one-fourth of the spatial variation in mortality of small- and medium-sized trees (<30
cm dbh), whereas no effects were detected in the first census interval. In particular, soil fertility was the most important predictor of tree mortality in the study area. Topography alone (altitude and slope) was associated with only 12% of the spatial variation in tree mortality and the magnitude of the effect of soil and topography on tree mortality also increased after storms. In general, plots on more fertile soils, on steep slopes and sandy soils in valleys showed greater tree mortality than those on plateau with well-drained clayey soils. Therefore, disturbance history and tree size should be included when scaling up tree mortality from local to regional scales. As much variation remains unexplained, other landscape features, such as watershed morphology and wind exposure, may be necessary to make more precise predictions on patterns of tree mortality in Central Amazonia.
Understanding how species respond to habitat boundaries in a landscape is essential because such responses influence several ecosystem processes and services. However, most studies to date are ...focused on boundaries between natural and human-made ecosystems, with few investigating species' responses to boundaries between natural habitats. Using a two-step approach, this paper examined how birds respond to gallery forest-savanna boundaries in an Amazonian savanna in Amapá, Brazil. First, we quantified bird species' abundance and boundary sensitivity. Then, we used phylogenetic linear regression to evaluate if five species-level characteristics (trophic level, dispersal ability, body size, niche breadth, and rarity) can be used as predictors of species' boundary sensitivities. We recorded 113 species, of which 67 had enough records to assess their responses to habitat edges. Most species (89%) crossed the boundaries between forests and savannas, with only seven species restricted to one of the habitats. Rarity is the only species trait that predicts a species' boundary sensitivity. Our results show that studies to date have underestimated the magnitude of the biological dynamics occurring along neotropical forest-savanna boundaries.
► Soil and topography predict only variation in tree mortality associated with storms. ► Topographic categories increase the importance of soil and topography on tree mortality. ► Under ...climate-change scenarios soil and topography may be useful predictors of mortality.
Tree mode of death provides insights as to why soil and topography explain only about 25% of the spatial variation in tree mortality in Central Amazonia, and permit predictions about what types of mortality are most probable under climate change. We studied tree mortality by mode of death in 72 1-ha permanent plots spanning 64
km
2 of tropical moist forest in Reserva Ducke, Manaus, Amazonas, Brazil. Plots were re-censused twice (2003–2005 and 2005–2008). Tree mode of death was assigned for trees ⩾4
cm dbh as standing, uprooted or snapped. We also recorded whether trees died alone or were pushed over by treefalls. Standing death was predominant, representing 54% of deaths of trees with dbh
⩾
10
cm, followed by snapping (26%) and uprooting (14%). Trees that fell alone represented 25% of deaths, while 16% were pushed over. Most small fallen dead trees (4
⩽
dbh
<
30
cm) were pushed over by other trees, while most large dead trees (dbh
⩾
30
cm) died alone. Standing mortality was weakly related to soil and topography, but 20% of variation in uprooted mortality and 11% in snapped mortality of trees with dbh
⩾
10
cm was explained by soil and topography. The variation in mortality explained for small trees (18% for uprooted mortality and 13% for snapped mortality) was higher than for large trees (14% for mortality by snapping only). In spite of little variation in mortality associated directly with soil and slope, analyses assessing the effect of topographic categories (plateaux, slope, and valley) on tree mortality detected higher differences, even though causal factors remain unidentified because topographic position may encompass both topographic and soil properties. There was an increase from the first to the second census interval in the effects associated with soil and topography on tree mortality by uprooting and snapping, and this was likely due to storms, which led to a disproportional increase in tree mortality for these tree modes of death. Presently, uprooting and snapping mortality are not dominant and the use of soil and topographic variables for modeling of tree mortality is therefore limited. However, under predicted climate-change scenarios of higher frequency of extreme storms, soil and topography may become more useful to improve estimates of tree mortality and biomass losses over large areas in Amazonia.
Although Amapá is the most protected Brazilian state, the same level of protection does not extend to its savannas. These are currently suffering increased pressure from threats including large-scale ...agriculture, particularly the expansion of soybean plantations. In September 2016, the Government of Amapá presented a zoning proposal (Zoneamento Socioambiental do Cerrado ZSC) that reserves most of the savannas for agricultural activities. Here, we outline how the methodology employed is flawed because it does not include fauna surveys, evaluations of ecosystem services or an assessment of the social importance of the savannas. The ZSC authors admit that, contrary to Brazilian legislation, the zoning was carried out with the single intention of increasing agriculture production. Current knowledge indicates that Amapá’s savannas are rich in biodiversity, including endemic and threatened species, and are also home to a rich culture of traditional populations. These savannas are important providers of ecosystem services that, if intact, could represent around US$ 1.52 billion annually. We hold that the ZSC should be reformulated, with fair participation of stakeholders, in accordance with Brazil’s legal requirements. At least 30% of the savannas should be protected, local family farming should be supported, and the rights of traditional peoples must now be assured through recognition of their land rights.
Fragmentation threatens biodiversity and forest-dwelling animals can be especially vulnerable. Neotropical primates inhabit forests and play ecological roles in maintaining forest biodiversity. ...Currently, many primate communities are restricted to forest fragments. We (1) evaluated the influence of environmental, matrix, and site attributes on species richness and functional traits of primates in the Neotropics; and (2) evaluated the effect of the sub-region on the relationships between primates and environmental, matrix, and site attributes. We conducted literature searches to find published data on primate communities in forest fragments throughout the Neotropics. Each fragment was assigned to 1 of 11 sub-regions: Mesoamerica, Tumbes-Chocó-Magdalena, Caribbean, Orinoco, Amazon, Atlantic Forest, Cerrado, Chaco, Andes, Caatinga, and Pampa. Based on actual and expected species occurrences, we calculated the proportion of primate species retained in the fragments, the mass retained, and dietary items retained considering reproductive and vegetative plant parts and prey. We used linear mixed models to correlate primate variables with environmental, matrix, and site attributes. Fragment area was more important for primate retention than environmental, matrix, and site attributes, with primate retention being higher in larger fragments. Fragment size was positively correlated with all primate variables, except for retention of prey consumption, whose retention decreased as water bodies and density of buildings in the matrix increased. Fragments within protected areas retained larger species than unprotected fragments. The proportion of extant mass retained and vegetative plant parts in the diet were highest in Mesoamerica and lowest in the Atlantic Forest. Conservation planning of Neotropical primates should consider both the differences among sub-regions, forest restoration to increase fragment size, and the creation of new protected areas, even in fragmented landscapes.
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