Environmental drivers of taxonomic and functional diversity of ant communities in a tropical mountain

2020 ◽  
Vol 13 (4) ◽  
pp. 393-403 ◽  
Author(s):  
Flávio Siqueira de Castro ◽  
Pedro Giovâni Da Silva ◽  
Ricardo Solar ◽  
Geraldo Wilson Fernandes ◽  
Frederico de Siqueira Neves
Keyword(s):  
Functional Diversity ◽  
Environmental Drivers ◽  
Ant Communities ◽  
Tropical Mountain

scholarly journals Including intraspecific trait variability to avoid distortion of functional diversity and ecological inference: lessons from natural assemblages

2020 ◽  
Author(s):  
Mark K. L. Wong ◽  
Carlos P. Carmona
Keyword(s):  
Functional Diversity ◽  
Probabilistic Methods ◽  
Environmental Drivers ◽  
Type I ◽  
List Type ◽  
Ecological Processes ◽  
Ant Communities ◽  
Functional Richness ◽  
Intraspecific Trait Variability ◽  
Trait Variability

ABSTRACTFunctional diversity assessments are crucial and increasingly used for understanding ecological processes and managing ecosystems. The functional diversity of a community is assessed by sampling traits at one or more scales (individuals, populations, species) and calculating a summary index of the variation in trait values. However, it remains unclear how the scale at which traits are sampled and the indices used to estimate functional diversity may alter the patterns observed and inferences about ecological processes.For 40 plant and 61 ant communities, we assess functional diversity using six methods – encompassing various mean-based and probabilistic methods – chosen to reflect common scenarios where different levels of detail are available in trait data. We test whether including trait variability at different scales (from individuals to species) alter functional diversity values calculated using volume-based and dissimilarity-based indices, Functional Richness (FRic) and Rao, respectively. We further test whether such effects alter the functional diversity patterns observed across communities and their relationships with environmental drivers such as abiotic gradients and occurrences of invasive species.Intraspecific trait variability strongly determined FRic and Rao. Methods using only species’ mean trait values to calculate FRic (convex hulls) and Rao (Gower-based dissimilarity) distorted the patterns observed when intraspecific trait variability was considered. These distortions generated Type I and Type II errors for the effects of environmental factors structuring the plant and ant communities.The high sensitivity of FRic to individuals with extreme trait values was revealed in comparisons of different probabilistic methods including among-individual and among-population trait variability in functional diversity. By contrast, values and ecological patterns in Rao were consistent among methods including different scales of intraspecific trait variability.Decisions about where traits are sampled and how trait variability is included in functional diversity can drastically change the patterns observed and conclusions about ecological processes. We recommend sampling the traits of multiple individuals per species and capturing their intraspecific trait variability using probabilistic methods. We discuss how intraspecific trait variability can be reasonably estimated and included in functional diversity in the common circumstance where only limited trait data are available.

scholarly journals The cryptic impacts of invasion: Functional homogenization of tropical ant communities by invasive fire ants

2019 ◽  
Author(s):  
Mark K. L. Wong ◽  
Benoit Guénard ◽  
Owen T. Lewis
Keyword(s):  
Functional Diversity ◽  
Taxonomic Diversity ◽  
Individual Species ◽  
Ecological Communities ◽  
Ant Communities ◽  
Invasive Insects ◽  
Tropical Grasslands ◽  
Functional Richness ◽  
Functional Identities ◽  
Functional Homogenization

AbstractInvasive insects represent major threats to ecosystems worldwide. Yet their effects on the functional dimension of biodiversity, measured as the diversity and distribution of traits, are overlooked. Such measures often determine the resilience of ecological communities and the ecosystem processes they modulate. The fire ant Solenopsis invicta is a highly problematic invasive species occurring on five continents. Its impacts on the taxonomic diversity of native ant communities have been studied but its impacts on their functional diversity are unknown. Comparing invaded and uninvaded plots in tropical grasslands of Hong Kong, we investigated how the presence of S. invicta affects the diversity and distribution of ant species and traits within and across communities, the functional identities of communities, and functionally unique species. We calculated the functional diversity of individual species, including the trait variation from intraspecific polymorphisms, and scaled up these values to calculate functional diversity at the community level. Invasion had only limited effects on species richness and functional richness, which were 13% and 8.5% lower in invaded communities respectively. In contrast, invasion had pronounced effects on taxonomic and functional composition due to turnover in species and trait values. Furthermore, invaded communities were functionally more homogeneous, displaying 23% less turnover and 56% more redundancy than uninvaded communities, as well as greater clustering and lower divergence in trait values. Invaded communities had fewer functionally-unique individuals and were characterized by ant species with narrower heads and bodies and shorter mandibles. Our results suggest that studies based only on taxonomic measures of diversity or indices describing trait variety risk underestimating the full ramifications of invasions. Investigating the diversity and distributions of traits at species, community and landscape levels can reveal the cryptic impacts of alien species which, despite causing little taxonomic change, may substantially modify the structure and functioning of ecological communities.

scholarly journals Do forest over- and understory respond to the same environmental variables when viewed at the taxonomic and trait level?

2021 ◽  
Author(s):  
Kenny Helsen ◽  
Yeng-Chen Shen ◽  
Tsung-Yi Lin ◽  
Chien-Fan Chen ◽  
Chu-Mei Huang ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Environmental Filtering ◽  
Soil Nutrient ◽  
Woody Species ◽  
Elevational Gradient ◽  
Functional Trait ◽  
Environmental Drivers ◽  
Small Scale ◽  
Diversity Patterns ◽  
Soil Variation

While the relative importance of climate filtering is known to be higher for woody species assemblages than herbaceous assemblage, it remains largely unexplored whether this pattern is also reflected between the woody overstory and herbaceous understory of forests. While climatic variation will be more buffered by the tree layer, the understory might also respond more to small-scale soil variation, next to experiencing additional environmental filtering due to the overstory's effects on light and litter quality. For (sub)tropical forests, the understory often contains a high proportion of fern and lycophyte species, for which environmental filtering is even less well understood. We explored the proportional importance of climate proxies and soil variation on the species, functional trait and (functional) diversity patterns of both the forest overstory and fern and lycophyte understory along an elevational gradient from 850 to 2100 m a.s.l. in northern Taiwan. We selected nine functional traits expected to respond to soil nutrient or climatic stress for this study and furthermore verified whether they were positively related across vegetation layers, as expected when driven by similar environmental drivers. We found that climate was a proportionally more important predictor than soil for the species composition of both vegetation layers and trait composition of the understory. The stronger than expected proportional effect of climate for the understory was likely due to fern and lycophytes' higher vulnerability to drought, while the high importance of soil for the overstory seemed driven by deciduous species. The environmental drivers affected different response traits in both vegetation layers, however, which together with additional overstory effects on understory traits, resulted in a strong disconnection of community-level trait values across layers. Interestingly, species and functional diversity patterns could be almost exclusively explained by climate effects for both vegetational layers, with the exception of understory species richness. This study illustrates that environmental filtering can differentially affect species, trait and diversity patterns and can be highly divergent for forest overstory and understory vegetation, and should consequently not be extrapolated across vegetation layers or between composition and diversity patterns.

scholarly journals Changes in taxonomic and functional diversity of plants in a chronosequence of Eucalyptus grandis plantations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pamela E. Pairo ◽  
Estela E. Rodriguez ◽  
M. Isabel Bellocq ◽  
Pablo G. Aceñolaza
Keyword(s):  
Species Richness ◽  
Leaf Litter ◽  
Plant Species ◽  
Functional Diversity ◽  
Soil Ph ◽  
Management Practices ◽  
Environmental Changes ◽  
Canopy Cover ◽  
Environmental Drivers ◽  
Natural Grasslands

AbstractTree plantations have become one of the fastest-growing land uses and their impact on biodiversity was evaluated mainly at the taxonomic level. The aim of this study was to analyze environmental changes after the Eucalyptus plantation in an area originally covered by natural grasslands, taking into account the alpha and beta (taxonomic and functional) diversity of plant communities. We selected nine plantation ages, along a 12 years chronosequence, with three replicates per age and three protected grasslands as the original situation. At each replicate, we established three plots to measure plant species cover, diversity and environmental variables. Results showed that species richness, and all diversity indices, significantly declined with increasing plantation age. Canopy cover, soil pH, and leaf litter were the environmental drivers that drove the decrease in taxonomic and functional diversity of plants through the forest chronosequence. Based on the path analyses results, canopy cover had an indirect effect on plant functional diversity, mediated by leaf litter depth, soil pH, and plant species richness. The high dispersal potential, annual, barochorous, and zoochorous plant species were the functional traits more affected by the eucalypt plantations. We recommend two management practices: reducing forest densities to allow higher light input to the understory and, due to the fact that leaf litter was negatively associated with all diversity facets, we recommend reducing their accumulation or generate heterogeneity in its distribution to enhance biodiversity.

Elevation and leaf litter interact in determining the structure of ant communities on a tropical mountain

Biotropica ◽  
2021 ◽  
Author(s):  
Jimmy Moses ◽  
Tom M. Fayle ◽  
Vojtech Novotny ◽  
Petr Klimes
Keyword(s):  
Leaf Litter ◽  
Ant Communities ◽  
Tropical Mountain

scholarly journals Exotic species invasions undermine regional functional diversity of freshwater fish

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marco Milardi ◽  
Anna Gavioli ◽  
Janne Soininen ◽  
Giuseppe Castaldelli
Keyword(s):  
Exotic Species ◽  
Functional Diversity ◽  
Current Knowledge ◽  
Biodiversity Loss ◽  
Taxonomic Diversity ◽  
Environmental Drivers ◽  
Ecological Traits ◽  
Species Invasions ◽  
Temporal And Spatial ◽  
Fine Resolution

AbstractExotic species invasions often result in native biodiversity loss, i.e. a lower taxonomic diversity, but current knowledge on invasions effects underlined a potential increase of functional diversity. We thus explored the connections between functional diversity and exotic species invasions, while accounting for their environmental drivers, using a fine-resolution large dataset of Mediterranean stream fish communities. While functional diversity of native and exotic species responded similarly to most environmental constraints, we found significant differences in the effects of altitude and in the different ranking of constraints. These differences suggest that invasion dynamics could play a role in overriding some major environmental drivers. Our results also showed that a lower diversity of ecological traits in communities (about half of less disturbed communities) corresponded to a high invasion degree, and that the exotic component of communities had typically less diverse ecological traits than the native one, even when accounting for stream order and species richness. Overall, our results suggest that possible outcomes of severe exotic species invasions could include a reduced functional diversity of invaded communities, but analyzing data with finer ecological, temporal and spatial resolutions would be needed to pinpoint the causal relationship between invasions and functional diversity.

Environmental drivers of fish functional diversity and composition in the Lower Colorado River Basin

2010 ◽  
Vol 67 (11) ◽  
pp. 1791-1807 ◽  
Author(s):  
Thomas K. Pool ◽  
Julian D. Olden ◽  
Joanna B. Whittier ◽  
Craig P. Paukert
Keyword(s):  
Life History ◽  
River Basin ◽  
Functional Diversity ◽  
Native Species ◽  
Fish Community ◽  
Colorado River ◽  
Colorado River Basin ◽  
Environmental Drivers ◽  
Lower Colorado River Basin ◽  
Lower Colorado River

Freshwater conservation efforts require an understanding of how natural and anthropogenic factors shape the present-day biogeography of native and non-native species. This knowledge need is especially acute for imperiled native fishes in the highly modified Lower Colorado River Basin (LCRB), USA. In the present study we employed both a taxonomic and functional approach to explore how natural and human-related environmental drivers shape landscape-scale patterns of fish community composition in the LCRB. Our results showed that hydrologic alteration, watershed land use, and regional climate explained 30.3% and 44.7% of the total variation in fish community taxonomic and functional composition, respectively. Watersheds with greater dam densities and upstream storage capacity supported higher non-native functional diversity, suggesting that dams have provided additional “niche opportunities” for non-native equilibrium life-history strategists by introducing new reservoir habitat and modifying downstream flow and thermal regimes. By contrast, watersheds characterized by greater upstream land protection, lower dam densities, and higher variation in spring and summer precipitation supported fish communities with a strong complement of native species (opportunistic–periodic strategists). In conclusion, our study highlights the utility of a life-history approach to better understand the patterns and processes by which fish communities vary along environmental gradients.

scholarly journals Small-scale drivers on plant and ant diversity in a grassland habitat through a multifaceted approach

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12517
Author(s):  
Michele Mugnai ◽  
Clara Frasconi Wendt ◽  
Paride Balzani ◽  
Giulio Ferretti ◽  
Matteo Dal Cin ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Wide Distribution ◽  
Small Scale ◽  
Ant Communities ◽  
Multifaceted Approach ◽  
Ant Community ◽  
Community Interest ◽  
Natural Grasslands ◽  
High Conservation ◽  
Ant Diversity

Semi-natural grasslands are characterized by high biodiversity and require multifaceted approaches to monitor their biodiversity. Moreover, grasslands comprise a multitude of microhabitats, making the scale of investigation of fundamental importance. Despite their wide distribution, grasslands are highly threatened and are considered of high conservation priority by Directive no. 92/43/EEC. Here, we investigate the effects of small-scale ecological differences between two ecosites present within the EU habitat of Community Interest of semi-natural dry grasslands on calcareous substrates (6210 according to Dir. 92/43/EEC) occurring on a Mediterranean mountain. We measured taxonomic and functional diversity of plant and ant communities, evaluating the differences among the two ecosites, how these differences are influenced by the environment and whether vegetation affects composition of the ant community. Our results show that taxonomic and functional diversity of plant and ant communities are influenced by the environment. While vegetation has no effect on ant communities, we found plant and ant community composition differed across the two ecosites, filtering ant and plant species according to their functional traits, even at a small spatial scale. Our findings imply that small-scale monitoring is needed to effectively conserve priority habitats, especially for those that comprise multiple microhabitats.

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