ABSTRACT
PREMISE: Understanding the responses of functional traits in tree species to climate variability is essential for predicting the future of tropical montane cloud forest (TMCF) tree species, especially in Andean montane environments where fog pockets act as moisture traps. METHODS: We studied the distribution of Magnolia gentryi, measured its spatial arrangement, identified local hotspots, and evaluated the extent to which climate-related factors are associated with its distribution. We then analyzed the variation in 13 functional traits of M. gentryi and the relationship with climate. RESULTS: Andean TMCF climatic factors constrain M. gentryi spatial distribution with significant patches or gaps that are associated with high precipitation and mean minimum temperature. The functional traits of M. gentryi are limited by the Andean TMCF climatic factors, resulting in reduced within-species variation in traits associated with water deficit. CONCLUSIONS: The association between functional traits and climate oscillation is crucial for understanding the growth conditions of relict-endemic species and is essential for conservation efforts. Forest trait diversity and species composition change because of fluctuations in hydraulic safety-efficiency gradients.
ABSTRACT
A critical step to design wildlife mitigating measures is the identification of roadkill hotspots. However, the effectiveness of mitigations based on roadkill hotspots depends on whether spatial aggregations are recurrent over time, spatially restricted, and most importantly, shared by species with diverse ecological and functional characteristics. We used a functional group approach to map roadkill hotspots for mammalian species along the BR-101/North RJ, a major road crossing important remnants of the Brazilian Atlantic Forest. We tested if functional groups present distinct hotspot patterns, and if they converge into the same road sectors, in that case, favoring optimal mitigating actions. Roadkill rates were monitored and recorded between October/2014 and September/2018 and species were classified into six functional groups based on their home range, body size, locomotion mode, diet, and forest-dependency. Hotspots along the roads were mapped for comparison of spatial patterns between functional groups. Results demonstrated that the roadkill index varied idiosyncratically for each functional group throughout the months and that no group presented seasonality. Seven hotspots were shared by two or more functional groups, highlighting the importance of these road stretches to regional mammal fauna. Two of the stretches are associated with aquatic areas extending from one side of the road to the other, and the remaining are connected to patches of native vegetation on both sides. This work brings a promising approach, yet hardly used in ecological studies on roads to analyze roadkill dynamics, assigning more importance to ecological instead of taxonomical characteristics, normally used to identify spatiotemporal patterns.
Subject(s)
Animals, Wild , Mammals , Animals , Brazil , ForestsABSTRACT
By increasing plant diversity in agroecosystems, it has been proposed that one can enhance and stabilize ecosystem functioning by increasing natural enemies' diversity. Food web structure determines ecosystem functioning as species at different trophic levels are linked in interacting networks. We compared the food web structure and composition of the aphid- parasitoid and aphid-hyperparasitoid networks in two differentially managed plum orchards: plums with inter-rows of oats as a cover crop (OCC) and plums with inter-rows of spontaneous vegetation (SV). We hypothesized that food web composition and structure vary between OCC and SV, with network specialization being higher in OCC and a more complex food web composition in SV treatment. We found a more complex food web composition with a higher species richness in SV compared to OCC. Quantitative food web metrics differed significantly among treatments showing a higher generality, vulnerability, interaction evenness, and linkage density in SV, while OCC presented a higher degree of specialization. Our results suggest that plant diversification can greatly influence the food web structure and composition, with bottom-up effects induced by plant and aphid hosts that might benefit parasitoids and provide a better understanding of the activity, abundance, and interactions between aphids, parasitoids, and hyperparasitoids in plum orchards.
ABSTRACT
Functional diversity is an emergent approach in ecology that has been applied globally to better understand the relationships between organisms and the environment. However, assessing the functional diversity of freshwater fish is a challenge for scientists. Aiming to summarize the evolution of scientific knowledge on fish functional diversity, we performed a systematic review of the literature published from 1945 to 2021 using the Web of Science. Based on the 101 articles reviewed, we found that publications about functional diversity of fishes have increased over time, mainly in Neotropical, Indomalayan and Palearctic regions. Most studies were conducted in lotic ecosystems, especially to assess environmental impacts such as biological invasions and land use. Functional diversity has been assessed mainly by morphological traits that reflect feeding and locomotion dimensions. Functional richness was the most common index used in the studies. Our findings suggest that political neglect and lack of investments may hamper the research development in several places. The missing information about the functional traits of many species may limit the use of the functional approach. We also highlight the need for the incorporation of functional diversity in conservation programs once functional diversity is a key facet of biodiversity to maintain freshwater ecosystem functioning.
A diversidade funcional tem sido avaliada principalmente através de traços funcionais morfológicos que refletem as dimensões da alimentação e locomoção. A Riqueza Funcional foi a métrica mais comumente usada nos estudos. Esses resultados sugerem que a negligência política e a falta de investimentos podem dificultar o desenvolvimento de pesquisas em diversas regiões. A falta de informações sobre os traços funcionais de muitas espécies limita o uso da abordagem funcional. Destaca-se também a necessidade de incorporar a diversidade funcional em programas de conservação, uma vez que a diversidade funcional é uma faceta chave da biodiversidade para manter o funcionamento dos ecossistemas de água doce.
Subject(s)
Animals , Aquatic Fauna , Biodiversity , Fishes/classification , Fresh WaterABSTRACT
The great majority of plants gain access to soil nutrients and enhance their performance under stressful conditions through symbiosis with arbuscular mycorrhizal fungi (AMF). The benefits that AMF confer vary among species and taxonomic groups. However, a comparative analysis of the different benefits among AMF has not yet been performed. We conducted a global meta-analysis of recent studies testing the benefits of individual AMF species and main taxonomic groups in terms of plant performance (growth and nutrition). Separately, we examined AMF benefits to plants facing biotic (pathogens, parasites, and herbivores) and abiotic (drought, salinity, and heavy metals) stress. AMF had stronger positive effects on phosphorus nutrition than on plant growth and nitrogen nutrition and the effects on the growth of plants facing biotic and abiotic stresses were similarly positive. While the AMF taxonomic groups showed positive effects on plant performance either with or without stress, Diversisporales were the most beneficial to plants without stress and Gigasporales to plants facing biotic stress. Our results provide a comprehensive analysis of the benefits of different AMF species and taxonomic groups on plant performance and useful insights for their management and use as bio-inoculants for agriculture and restoration.
Subject(s)
Glomeromycota , Mycorrhizae , Plant Roots , Plants/microbiology , SymbiosisABSTRACT
Abstract Interactions between plant and pollinators are associated with the origin and maintenance of species diversity, as well as ecosystem functioning. The potential of pollination as an ecosystem service is evidenced by its association with food production. Understanding pollination at the landscape scale is essential for characterizing the pollination service for several crops that depend on pollinators for fruit and seed set that make up the human diet. Our aim was to carry out a literature review of studies and projects funded by BIOTA/FAPESP to illustrate the main research approaches developed in the field of Pollination Biology, especially related to plant-pollinator interactions. Plant-pollinator interactions in the Atlantic forest were leveraged as a result of this long-term research program, during which several papers were published in international journals. Pollination by bees (melittophily) was the most representative pollination system studied. In addition to melittophily, other interactions were studied such as pollination by hawkmoths (sphingophily), by hummingbirds (ornithophily) and by bats (chiropterophily). The specific mutualistic relationships between fig trees and fig wasps were also subject of studies within the Program. At the beginning of the BIOTA/FAPESP Program, there were many gaps in basic information about pollination and breeding systems of Brazilian native plant species. Thus, the Program was fundamental to fuel research on the natural history of plants and pollinators from the Atlantic forest. Overall, the Program funded studies that investigated themes such as functional pollination ecology, pollinator effectiveness, plant population genetics, structure and dynamics of plant-pollinator interaction networks, as well as geographic distribution and macroevolution of pollination systems, as well as genetic and molecular studies of native plant populations focusing on pollen flow and genetic structure of populations. Additionally, studies on pollination in the context of landscape ecology had the aim of assessing the effects of forest fragmentation on the functioning of plant populations and their interactions with pollinators and the relationships between landscape structure and ecological processes, biodiversity, and ecosystem service. Therefore, the Program had a prominent role in producing basic data with great implications for understanding the ecology and promoting the conservation of plant-pollinator interactions.
Resumo A interação planta-polinizador está associada à origem e manutenção da diversidade de espécies de plantas e ao funcionamento dos ecossistemas. O potencial da polinização como serviço ecossistêmico é destacado quando associado à produção de alimentos. Compreender esta interação na escala da paisagem é essencial para caracterizar o serviço de polinização para muitos cultivos que dependem dos polinizadores para a formação de frutos e sementes que integram a dieta humana. O objetivo deste trabalho foi realizar uma revisão bibliográfica de estudos e projetos financiados pelo BIOTA/FAPESP para ilustrar as principais abordagens de pesquisa desenvolvidas no campo da Biologia da Polinização, especialmente relacionadas à interação planta-polinizador. As interações planta-polinizador na Mata Atlântica foram alavancadas como resultado desse programa de pesquisa de longo prazo, durante o qual vários artigos foram publicados em revistas internacionais. A polinização por abelhas (melitofilia) foi o sistema de polinização mais representativo estudado. Além da melitofilia, outras interações foram estudadas, como a polinização por mariposas (esfingofilia), por beija-flores (ornitofilia) e por morcegos (quiropterofilia). As relações mutualísticas específicas entre figueiras e vespas do figo também foram objeto de estudos no âmbito do Programa. No início do Programa BIOTA/FAPESP, havia muitas lacunas sobre informações básicas sobre polinização e sistemas de reprodução de espécies vegetais nativas brasileiras. Assim, o Programa foi fundamental para desenvolver pesquisas sobre a história natural de plantas e polinizadores da Mata Atlântica. No geral, o Programa financiou estudos que investigaram temas como ecologia funcional da polinização, eficácia de polinizadores, genética de populações de plantas, estrutura e dinâmica de redes de interação planta-polinizador, bem como distribuição geográfica e macroevolução dos sistemas de polinização, além de estudos genéticos e moleculares de populações de plantas nativas com foco no fluxo de pólen. Adicionalmente, estudos sobre polinização no contexto da ecologia da paisagem tiveram como objetivo avaliar os efeitos da fragmentação florestal no funcionamento das populações de plantas e suas interações com os polinizadores e as relações entre a estrutura da paisagem e os processos ecológicos, biodiversidade e serviços ecossistêmicos. Portanto, o Programa teve um papel de destaque na produção de dados básicos com grandes implicações para o entendimento da ecologia e promoção da conservação das interações planta-polinizador.
ABSTRACT
Understanding the role of species traits in mediating ecological interactions and shaping community structure is a key question in ecology. In this sense, parasite population parameters allow us to estimate the functional importance of traits in shaping the strength of interactions among hosts and parasites in a network. The aim of this study was to survey and analyse the small mammal-helminth network in a forest reserve of the Brazilian Atlantic Forest in order to understand (i) how functional traits (type of parasite life cycle, site of infection in their host, host and parasite body length, host diet, host locomotor habit and host activity period) and abundance influence hostparasite interactions, (ii) whether these traits explain species roles, and (iii) if this relationship is consistent across different parasite population parameters (presence and absence, mean abundance and prevalence). Networks were modular and their structural patterns did not vary among the population parameters. Functional traits and abundance shaped the interactions observed between parasites and hosts. Host species abundance, host diet and locomotor habit affected their centrality and/or vulnerability to parasites. For helminths, infection niche was the main trait determining their central roles in the networks.
Subject(s)
Helminthiasis, Animal/parasitology , Helminths/physiology , Marsupialia/parasitology , Rodent Diseases/parasitology , Animals , Brazil/epidemiology , Didelphis/parasitology , Helminthiasis, Animal/epidemiology , Helminths/anatomy & histology , Helminths/classification , Host-Parasite Interactions , Rodent Diseases/epidemiology , RodentiaABSTRACT
Secondary forests emerging during traditional shifting cultivation practices are increasingly recognized for their fulfillment of ecosystem services and mitigation potential of climate change and biodiversity losses. The soil seed bank as a recruit reservoir is a limiting factor for natural forest regeneration of such secondary forests and is decisive for the formation and restitution of the post-disturbance community. The aim of this study was to compare the composition of the soil seed bank along a natural regeneration chronosequence from the Caxiuanã National Forest, eastern Amazon, including old-growth reference sites. We sampled standing vegetation, soil properties and soil seed banks and compared the density and species richness of different life forms among different regeneration stages. Using nonmetric, multiple scaling, we compared the composition of the soil seed bank among different regeneration stages and with standing vegetation composition. Furthermore, we outlined the influence of stand age, vegetation structure and soil properties on the density, richness and functional characterization of the soil seed bank using mixed effect models. The soil seed bank was dominated by herb seeds in all regeneration stages, and the density and richness of tree seeds increased with regeneration time and recovery of vegetation structure. Seed bank composition changed gradually with regeneration advance and differed from standing vegetation, containing a high amount of allochthonous seeds, especially in older stands. This observation highlights the importance of dispersal and habitat connectivity for the natural regeneration of these secondary forests. Shifts in soil seed bank composition towards slow-growing, animal-dispersed, non-pioneer species with larger, recalcitrant seeds in older regeneration stands indicate changes in vegetation composition along succession. Thus, our data indicate the importance of connectivity for forest regeneration and long fallow periods (> 40 years) to increase the performance of ecosystem services, resilience and stability of secondary forests arising during shifting cultivation practices.
Subject(s)
Seed Bank , Soil , Ecosystem , Forests , Seeds , TreesABSTRACT
The ecology and structure of many tropical coral reefs have been markedly altered over the past few decades. Although long-term recovery has been observed in terms of coral cover, it is not clear how novel species configurations shape reef functionality in impaired reefs. The identities and life-history strategies of the corals species that recover are essential for understanding reef functional dynamics. We used a species identity approach to quantify the physical functionality outcomes over a 13 year period across 56 sites in the Mexican Caribbean. This region was affected by multiple stressors that converged and drastically damaged reefs in the early 2000s. Since then, the reefs have shown evidence of a modest recovery of coral cover. We used Bayesian linear models and annual rates of change to estimate temporal changes in physical functionality and coral cover. Moreover, a functional diversity framework was used to explore changes in coral composition and the traits of those assemblages. Between 2005 and 2018, physical functionality increased at a markedly lower rate compared to that of coral cover. The disparity between recovery rates depended on the identity of the species that increased (mainly non-framework and foliose-digitate corals). No changes in species dominance or functional trait composition were observed, whereas non-framework building corals consistently dominated most reefs. Although the observed recovery of coral cover and functional potential may provide some ecological benefits, the long-term effects on reef frameworks remain unclear, as changes in the cover of key reef-building species were not observed. Our findings are likely to be representative of many reefs across the wider Caribbean basin, as declines in coral cover and rapid increases in the relative abundance of weedy corals have been reported regionally. A coral identity approach to assess species turnover is needed to understand and quantify changes in the functionality of coral reefs.
Subject(s)
Anthozoa , Animals , Bayes Theorem , Caribbean Region , Coral Reefs , Mexico , West IndiesABSTRACT
Amazonian droughts are increasing in frequency and severity. However, little is known about how this may influence species-specific vulnerability to drought across different ecosystem types. We measured 16 functional traits for 16 congeneric species from six families and eight genera restricted to floodplain, swamp, white-sand or plateau forests of Central Amazonia. We investigated whether habitat distributions can be explained by species hydraulic strategies, and if habitat specialists differ in their vulnerability to embolism that would make water transport difficult during drought periods. We found strong functional differences among species. Nonflooded species had higher wood specific gravity and lower stomatal density, whereas flooded species had wider vessels, and higher leaf and xylem hydraulic conductivity. The P50 values (water potential at 50% loss of hydraulic conductivity) of nonflooded species were significantly more negative than flooded species. However, we found no differences in hydraulic safety margin among species, suggesting that all trees may be equally likely to experience hydraulic failure during severe droughts. Water availability imposes a strong selection leading to differentiation of plant hydraulic strategies among species and may underlie patterns of adaptive radiation in many tropical tree genera. Our results have important implications for modeling species distribution and resilience under future climate scenarios.
Subject(s)
Droughts , Trees , Brazil , Ecosystem , Plant Leaves , Water , XylemABSTRACT
BACKGROUND: Alternative organism designs (i.e. the existence of distinct combinations of traits leading to the same function or performance) are a widespread phenomenon in nature and are considered an important mechanism driving the evolution and maintenance of species trait diversity. However, alternative designs are rarely considered when investigating assembly rules and species effects on ecosystem functioning, assuming that single trait trade-offs linearly affect species fitness and niche differentiation. SCOPE: Here, we first review the concept of alternative designs, and the empirical evidence in plants indicating the importance of the complex effects of multiple traits on fitness. We then discuss how the potential decoupling of single traits from performance and function of species can compromise our ability to detect the mechanisms responsible for species coexistence and the effects of species on ecosystems. Placing traits in the continuum of organism integration level (i.e. traits hierarchically structured ranging from organ-level traits to whole-organism traits) can help in choosing traits more directly related to performance and function. CONCLUSIONS: We conclude that alternative designs have important implications for the resulting trait patterning expected from different assembly processes. For instance, when only single trade-offs are considered, environmental filtering is expected to result in decreased functional diversity. Alternatively, it may result in increased functional diversity as an outcome of alternative strategies providing different solutions to local conditions and thus supporting coexistence. Additionally, alternative designs can result in higher stability of ecosystem functioning as species filtering due to environmental changes would not result in directional changes in (effect) trait values. Assessing the combined effects of multiple plant traits and their implications for plant functioning and functions will improve our mechanistic inferences about the functional significance of community trait patterning.
Subject(s)
Ecosystem , Plants , Biodiversity , Phenotype , Plant Physiological PhenomenaABSTRACT
Species distribution is strongly driven by local and global gradients in water availability but the underlying mechanisms are not clear. Vulnerability to xylem embolism (P50 ) is a key trait that indicates how species cope with drought and might explain plant distribution patterns across environmental gradients. Here we address its role on species sorting along a hydro-topographical gradient in a central Amazonian rainforest and examine its variance at the community scale. We measured P50 for 28 tree species, soil properties and estimated the hydrological niche of each species using an indicator of distance to the water table (HAND). We found a large hydraulic diversity, covering as much as 44% of the global angiosperm variation in P50 . We show that P50 : contributes to species segregation across a hydro-topographic gradient in the Amazon, and thus to species coexistence; is the result of repeated evolutionary adaptation within closely related taxa; is associated with species tolerance to P-poor soils, suggesting the evolution of a stress-tolerance syndrome to nutrients and drought; and is higher for trees in the valleys than uplands. The large observed hydraulic diversity and its association with topography has important implications for modelling and predicting forest and species resilience to climate change.
Subject(s)
Rainforest , Trees/physiology , Water , Xylem/physiology , Phylogeny , Species SpecificityABSTRACT
Air pollution and the urban heat island effect are known to directly affect ecosystems in urban areas. Lichens, which are widely known as good ecological indicators of air quality and of climatic conditions, can be a valuable tool to monitor environmental changes in urban environments. The objective of this work was to select lichen functional traits and functional groups that can be used as ecological indicators of the effects of urbanization, with emphasis in the Southern subtropics, where this had never been done. For that, we assessed lichen functional composition in urban sites with different population density, which was considered as proxy for grouping sites in two levels of urbanization (low and medium/high). This a priori grouping was based on their significantly differences on air pollutants and land cover. Urbanization and air pollution showed to affect all lichen functional traits, with different responses depending on the functional group. Medium/high density urbanization was associated to an increase on the mean relative abundance of lichens with chlorococcoid green algae, foliose narrow lobes, soredia as the main reproduction strategy, pruinose thallus and containing secondary metabolites for chemical protection. Lower density urbanization showed a higher relative frequency of cyanolichens and lichens with Trentepohlia as the main algae, loosely attached crustose thallus and isidia as the main reproductive structure. The differences found on photobiont and growth form traits in response to the environmental variables used as proxies of microclimatic conditions (forest cover and number of trees around the sampling units), enabled us to detect the urban heat island effect (drier conditions in more urbanized sites).
Subject(s)
Air Pollution/analysis , Environmental Monitoring/methods , Lichens/physiology , Air Pollutants/analysis , Brazil , Chlorophyta/growth & development , Chlorophyta/physiology , Lichens/classification , Lichens/growth & development , Reproduction , UrbanizationABSTRACT
This work aimed to evaluate the effect of sewage sludge application as fertilizer on the plasticity of functional characteristics of species commonly found in the Caatinga. The research was developed in the nursery of the Federal Institute of Education, Science and Technology of Ceará (IFCE), Quixadá campus, located in northeastern Brazil. Three treatments were applied: raw sludge, sanitized sludge, and no manipulation. In each treatment, five species were planted, each with five individuals, totaling 75 individuals, which were tagged, and 4 months after germination, they were destroyed to obtain dry matter content (TMSF) from leaf, stem (TMSC), fine root (TMSRF), and thick root (TMSRG); leaf area; height and diameter of the seedling; and length above and below the ground. The sanitized sludge was responsible for giving higher values for leaf area, height of the seedlings, and diameter and length of stem and root. However, the dry matter content of the fine roots was higher in the treatment without manipulation. At the community level, as TMSRG increased, TMSC also increased, the same occurred between TMSRG and TMSRF, TMSC and TMSRF, and stem length and leaf area. In the treatment without manipulation, there was a positive correlation between leaf area, height and plant diameter, and negative correlation between root length and plant diameter. Thus, it can be concluded that the use of sanitized sludge is a good tool to increase the availability of soil resources, conferring to individuals' greater dry matter content, greater leaf area, and higher height and diameter above the ground.
Subject(s)
Environmental Monitoring , Fertilizers , Plant Physiological Phenomena , Agriculture/methods , Brazil , Germination , Plant Leaves , Plant Roots , Plant Stems , Seedlings , Sewage/chemistry , Soil , Waste Disposal, Fluid/methodsABSTRACT
Research regarding biodiversity and ecosystem services has been demonstrating a positive correlation among the ecosystem processes, such as the carbon sink into plant biomass and the quantity of carbon in natural vegetation. Nonetheless, it is hard to understand the biodiversity measurements, because they involve gene, phenotypic, population, species, community and ecosystem diversity. The functional diversity refers to the species richness and variety, their characteristics and how that affects the functioning of an ecosystem. Primary productivity is a key factor that affects the functioning of a forest ecosystem. Thus, the aim of this paper was to evaluate the influence of functional diversity on the woody volume productivity (as a proxy for primary production) in the Brazilian savanna. We used six functional characteristics, and to verify the relation between forest production and functional diversity facets, we tested many models. Regarding wood volume, the best models were the exponential and logarithmic. None of the linear models showed significant regression parameters as there was no additive relationship among the multifaceted aspects of functional diversity and wood volume. We found a positive correlation between the functional diversity and primary productivity, which can be used to forecast the effects of diversity variation on ecosystem services.
Pesquisas sobre biodiversidade e serviços ecossistêmicos tem demonstrado uma correlação positiva entre os processos do ecossistema, como a absorção de carbono pela biomassa vegetal. No entanto, é difícil entender a medida da biodiversidade, porque ela envolve a diversidade de genes, fenotípica, população, espécie, comunidade e ecossistema. A diversidade funcional ser refere a quantidade e a variedade de espécies, suas características e como isso afeta o funcionamento de um ecossistema. Produtividade primária é um fator chave que afeta o funcionamento de um ecossistema florestal. Assim, o objetivo deste trabalho foi avaliar a influência da diversidade funcional quanto à produtividade de volume de madeira. Usamos seis características funcionais. Para verificar a relação entre a produção florestal e aspectos da diversidade funcional, testamos diversos modelos. Em relação ao volume, os melhores modelos foram os exponenciais e logarítmicos. Nenhum dos modelos lineares mostrou parâmetros significativos ou regressão, ou seja, não existe relação aditiva entre os aspectos multifacetados da diversidade funcional e o volume de madeira. Encontramos uma correlação positiva entre a diversidade funcional e a produtividade primária que permite uma melhor previsão dos efeitos das alterações da diversidade funcional sobre os serviços ecossistêmicos.
Subject(s)
Ecosystem , Grassland , BiodiversityABSTRACT
The seed-to-seedling transition constitutes a critical bottleneck in the life history of plants and represents a major determinant of species composition and abundance. However, we have surprisingly little knowledge regarding the forces driving this ontogenetic transition. Here we utilize information regarding organismal function to investigate the strength of intra- and interspecific negative density dependence during the seed-to-seedling transition in Puerto Rican tree species. Our analyses were implemented at individual sites and across an entire 16-ha forest plot, spanning 6 years. The functional richness of seedling assemblages was significantly lower than expected given the seed assemblages, but the functional evenness was significantly higher than expected, indicating the simultaneous importance of constraints on the overall phenotypic space and trait differences for successful transitions from seed to seedling. The results were consistent across years. Within species, we also found evidence for strong intraspecific negative density dependence, where the probability of transition was proportionally lower when in a site with high conspecific density. These results suggest that filtering of similar phenotypes across species and strong negative density dependence within and among species are simultaneously driving the structure and dynamics of tropical tree assemblages during this critical life-history transition.
Subject(s)
Population Density , Seedlings/growth & development , Seeds/growth & development , Trees/physiology , Ecosystem , Population Dynamics , Puerto Rico , Trees/growth & development , Tropical ClimateABSTRACT
ResumenLos escarabajos pasálidos son componentes importantes de los bosques tropicales debido a que facilitan el reciclaje de nutrientes propios de madera en descomposición, ya sea por acción directa (consumo) o indirecta (facilitando la acción de otros organismos). En la actualidad los estudios ecológicos dentro del grupo son escasos y se han centrado en respuestas a cambios ambientales relacionados con su recurso alimenticio. En el presente estudio se caracterizó la composición gremial de escarabajos pasálidos, distribuida en un gradiente altitudinal, de acuerdo a sus características de aprovechamiento del recurso. Se cuantificaron aspectos morfoecológicos de importancia adaptativa para la explotación diferencial del recurso (medidas corporales, puntos homólogos en cuerpo y alas y series de Fourier en protibias). Se reconocieron cinco especies, 198 grupos familiares y tres gremios: el subcortícola, el alboduramícola y el generalista. La riqueza de la comunidad disminuyó conforme aumentó la altitud. Los cambios entre las variables morfométricas lineales se vieron influenciadas por la altitud; por su parte, los datos morfogeométricos se comportaron independientes del gradiente. El análisis de marcadores morfológicos (morfogeométrico) arrojó información relevante para la delimitación de los gremios ya establecidos en esta familia. Dentro de estos, la forma general del cuerpo junto a las tibias anteriores, aportaron la mayor información de agrupación gremial. La cuantificación de dichos marcadores evidenció la relación entre los tipos de aprovechamiento del recurso, ya que al ser estructuras importantes en el movimiento y consumo de la madera en microzonas particulares, permite plantear roles funcionales puntuales. Reconocer estas variables en interacción con aquellas ecológicas brinda herramientas para el entendimiento de la riqueza y los aportes funcionales de los escarabajos pasálidos al ecosistema.
AbstractBess beetles are important components on tropical forest dead wood nutrient cycling, since they act as direct consumers and ease the consumption by another organism (indirect). Studies of bess beetle ecology are scarce and have focused on communities responses to environmental changes on alimentary resources. We characterized the bess beetles guild composition in an elevation gradient, according to their differential use of resources (microhabitat) and morphological traits quantification (geometric and lineal), as a potential tool to improve our understanding on resource use and functional ecology of beetles. Three guilds (underbark, sapwood-heartwood and generalists feeders), five species and 198 familiar groups were recognized; their richness decreased as elevation increased. Changes in linear morphometric measures were influenced by elevation; morphogeometrical measures were not associated with the elevation gradient, only grouping at guild level were observed. Morphological markers analysis (morphometric) provided information to guild delimitation. Body and metatibiae shape contributed with the best information to guild grouping. Quantification of those structural markers proved the relationship between resource repartition, because they are involved in movement on wood galleries and wood consumption, this fact allowed to propose specific functional roles. The identified patterns have contributed on the understanding of functional processes in Passalidae communities and their role in ecosystem function.
Subject(s)
Animals , Coleoptera/anatomy & histology , Tropical Climate , Coleoptera/classification , Coleoptera/physiology , Forests , Colombia , BiodiversityABSTRACT
Epiphytes are strongly dependent on the conditions created by their host's traits and a certain degree of specificity is expected between them, even if these species are largely abundant in a series of tree hosts of a given environment, as in the case of atmospheric bromeliads. Despite their considerable abundance in these environments, we hypothesize that stochasticity alone cannot explain the presence and abundance of atmospheric bromeliads on host trees, since host traits could have a greater influence on the establishment of these bromeliads. We used secondary and reforested seasonal forests and three distinct silvicultures to test whether species richness, phylogenetic diversity and functional diversity of trees can predict the differential presence, abundance and distribution of atmospheric bromeliads on hosts. We compared the observed parameters of their assemblage with null models and performed successive variance hierarchic partitions of abundance and distribution of the assemblage to detect the influence of multiple traits of the tree hosts. Our results do not indicate direct relationships between the abundance of atmospheric bromeliads and phylogenetic or functional diversity of trees, but instead indicate that bromeliads occurred on fewer tree species than expected by chance. We distinguished functional tree patterns that can improve or reduce the abundance of atmospheric bromeliads, and change their distribution on branches and trunk. While individual tree traits are related to increased abundance, species traits are related to the canopy distribution of atmospheric bromeliad assemblages. A balance among these tree functional patterns drives the atmospheric bromeliad assemblage of the forest patches.
ABSTRACT
It was analyzed the diversity of the ichthyofauna in the inner portion of the Amazon Estuary, its spatial and temporal distribution and abundance considering the salinity gradient and the importance of the area as reproduction and nursery grounds. Data was obtained in Guajará and Marajó Bays, and the Guamá River. Specimens were captured in the main channel (gillnets and trawl nets) and tidal creeks (block nets) between 2004 and 2011 during the dry (July-December) and rainy seasons (January-June). A total of 41,516 specimens of 136 taxa were observed. Differential fish composition, abundance and use of the zones as nursery and breeding area were observed, driven mainly by the salinity. The main river channel of Marajó Bay returned the highest values of abundance, especially during the dry season. The tidal creeks were used more frequently as reproduction area than the main river channels. Small-sized fishes predominated in all zones. Total species richness (S), diversity and abundance (main river channel) was highest in Marajó Bay and lowest in Guamá River (richness) and Guajará Bay (Margalefs D and Shannons H). The most species, especially in Guajará and Marajó Bays, were occasional and accessory, characterizing the study area as a transitional zone, with the presence of freshwater, estuarine and marine species in all stages of the life history. The systematic monitoring of the area should be given the highest priority, considering the importance of this area in terms of biodiversity and as a source of income and subsistence for local populations.(AU)
Foi analisada a diversidade da ictiofauna na parte interna do Estuário Amazônico, sua distribuição espacial e temporal e abundância considerando o gradiente de salinidade e a importância da zona para reprodução e berçário. Os dados foram obtidos nas baías de Guajará e Marajó e no rio Guamá. Os espécimes foram capturados no canal principal (redes de emalhar e redes de arrasto) e canais de maré (redes de tapagem) entre 2004 e 2011 durante a estação seca (julho-dezembro) e estação chuvosa (janeiro-junho). Um total de 41.516 espécimes e 136 táxons foi observado. Diferenças na composição dos peixes, abundância, uso da zona para berçário e criação, impulsionada, principalmente, pela salinidade, foram observadas. O canal principal da baía de Marajó resultou nos maiores valores de abundância, especialmente durante a estação seca. O canal de maré foi usado mais frequentemente como área de reprodução do que os canais principais. Peixes de pequeno porte predominaram em todas as zonas. A riqueza de espécies (S), diversidade e abundância (canal principal) foi maior na baía de Marajó e menor no rio Guamá (riqueza) e Guajará (Margalefs D e Shannons H). A maioria das espécies, especialmente nas baías de Guajará e Marajó, foi ocasional e acessória, caracterizando a área de estudo como zona de transição, com a presença de espécies de água doce, estuarinas e marinhas em todas as fases do ciclo de vida. O acompanhamento sistemático da área deve ser da mais alta prioridade, considerando a importância desta área em termos de biodiversidade e fonte de renda e subsistência para as populações locais.(AU)