scholarly journals Can functional traits explain phylogenetic signal in the composition of a plant community?

2015 ◽  
Author(s):  
Daijiang Li ◽  
Anthoy R Ives ◽  
Donald M Waller

Phylogeny-based and functional trait-based analyses are two principle ways to study community assembly and underlying ecological processes. In principle, knowing all information about species traits would make phylogenetic information redundant, at least that component of phylogenetic signal in the distribution of species among communities that is caused by phylogenetically related species sharing similar traits. In reality, phylogenies may contain more information than a set of singular, discretely measured traits because we cannot measure all species traits and may misjudge which are most important. The extent to which functional trait information makes phylogenetic information redundant, however, has not been explicitly studied with empirical data in community ecology. Here, we use phylogenetic linear mixed models to analyze community assembly of 55 understory plant species in 30 forest sites in central Wisconsin. These communities show strong phylogenetic attraction, yet variation among sites in 20 environmental variables could not account for this pattern. Most of the 15 functional traits we measured had strong phylogenetic signal, but only three varied strongly among sites in ways that affected species' abundances. These three traits explained only 19% of variation in phylogenetic patterns of species co-occurrence. Thus, phylogenies appear to provide considerably more information about community assembly than the functional traits measured in this study, demonstrating the value of phylogeny in studying of community assembly processes even with abundant functional traits.

2019 ◽  
pp. 231-246
Author(s):  
Gary G. Mittelbach ◽  
Brian J. McGill

There is perhaps no more fundamental question in ecology than what determines the number and kinds of species found in a community and their relative abundances. This chapter lays out a powerful approach to answering this question, based on the concepts of a regional species pool and environmental filters. The species pool is the set of species that could potentially colonize a local site or community. Of these potential colonists, some species are limited in their ability to disperse to site, some are limited by their ability to survive the abiotic environment, and some are limited by their interactions with other species. These “filters” act individually or in concert, and the functional traits of species determine their success in passing through these filters to colonize a local site. There is growing empirical evidence that both abiotic and biotic processes select for specific functional traits. Focusing on the functional traits of species may lead to rules of community assembly that are general and help unify a variety of more specific theories.


2021 ◽  
Vol 12 ◽  
Author(s):  
Qi Yan ◽  
Jianming Deng ◽  
Feng Wang ◽  
Yongqin Liu ◽  
Keshao Liu

Microbial communities normally comprise a few core species and large numbers of satellite species. These two sub-communities have different ecological and functional roles in natural environments, but knowledge on the assembly processes and co-occurrence patterns of the core and satellite species in Tibetan lakes is still sparse. Here, we investigated the ecological processes and co-occurrence relationships of the core and satellite bacterial sub-communities in the Tibetan lakes via 454 sequencing of 16S rRNA gene. Our studies indicated that the core and satellite bacterial sub-communities have similar dominant phyla (Proteobacteria, Bacteroidetes, and Actinobacteria). But the core sub-communities were less diverse and exhibited a stronger distance-decay relationship than the satellite sub-communities. In addition, topological properties of nodes in the network demonstrated that the core sub-communities had more complex and stable co-occurrence associations and were primarily driven by stochastic processes (58.19%). By contrast, the satellite sub-communities were mainly governed by deterministic processes (62.17%). Overall, this study demonstrated the differences in the core and satellite sub-community assembly and network stability, suggesting the importance of considering species traits to understand the biogeographic distribution of bacterial communities in high-altitude lakes.


2014 ◽  
Vol 41 (3) ◽  
pp. 301 ◽  
Author(s):  
Johanna M. Toivonen ◽  
Viviana Horna ◽  
Michael Kessler ◽  
Kalle Ruokolainen ◽  
Dietrich Hertel

Plant functional traits can be genetically determined or phenotypically plastic. We assessed the degree of genetic determinism in the functional traits of Andean Polylepis tree species among 14 important traits that enable the species to withstand cold and dry conditions. We conducted a common garden experiment and related the species-specific means of the functional traits to the variables of climatic niche optima of the species (mean annual temperature and annual precipitation), deducing that if the interspecific variation in the functional trait is related to the species climatic niche optima according to the theoretically-expected pattern of climate-trait relationship, the variation of the trait must be genetically determined. In general, the traits were related either to species temperature or precipitation optima. For example, leaf size, maximum photosynthesis rate and root tip abundance were related to temperature, whereas light compensation and light saturation points were related to precipitation. Only leaf size showed a significant phylogenetic signal, indicating that most of the manifested climate–trait relationships are not caused purely by phylogeny, but are mainly a result of species specialisation along an environmental gradient. However, in many cases the relationships were rather weak. This suggests that important functional traits of Polylepis species involve both genetic and phenotypic components aiming to maximise the overall fitness of the species at high elevations.


Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 485
Author(s):  
Anna Łubek ◽  
Martin Kukwa ◽  
Bogdan Jaroszewicz ◽  
Patryk Czortek

Current trends emphasize the importance of the examination of the functional composition of lichens, which may provide information on the species realized niche diversity and community assembly processes, thus enabling one to understand the specific adaptations of lichens and their interaction with the environment. We analyzed the distribution and specialization of diverse morphological, anatomical and chemical (lichen secondary metabolites) traits in lichen communities in a close-to-natural forest of lowland Europe. We considered these traits in relation to three levels of forest ecosystem organization: forest communities, phorophyte species and substrates, in order to recognize the specialization of functional traits to different levels of the forest complexity. Traits related to the sexual reproduction of mycobionts (i.e., ascomata types: lecanoroid apothecia, lecideoid apothecia, arthonioid apothecia, lirellate apothecia, stalked apothecia and perithecia) and asexual reproduction of mycobionts (pycnidia, hyphophores and sporodochia) demonstrated the highest specialization to type of substrate, tree species and forest community. Thallus type (foliose, fruticose, crustose and leprose thalli), ascospore dark pigmentation and asexual reproduction by lichenized diaspores (soredia and isidia) revealed the lowest specialization to tree species and substrate, as well as to forest community. Results indicate that lichen functional trait assemblage distribution should not only be considered at the level of differences in the internal structure of the analyzed forest communities (e.g., higher number of diverse substrates or tree species) but also studied in relation to specific habitat conditions (insolation, moisture, temperature, eutrophication) that are characteristic of a particular forest community. Our work contributes to the understanding of the role of the forest structure in shaping lichen functional trait composition, as well as enhancing our knowledge on community assembly rules of lichen species.


2021 ◽  
Author(s):  
Melissa Johnson

Abstract Tropical rainforest communities are often characterized by a small number of species-rich genera that contribute disproportionately to the alpha diversity in these habitats. In the Pacific Basin there are nearly 200 species of Cyrtandra, most of which are white-flowered woody shrubs that are single-island endemics. Within these island communities, multiple Cyrtandra species are commonly observed to occur sympatrically in wet forest understories, forming swarms of what appear to be ecologically similar taxa. The aim of this study was to determine if communities of these plants are randomly assembled with respect to phylogenetic relatedness and traits that are ecologically relevant. Using a combination of ten functional traits and a well-resolved species phylogeny, I examined community assembly within 34 species of Cyrtandra across three Pacific archipelagoes. Coexisting species were generally found to be more closely related and more phenotypically similar than would be expected by chance. This pattern was observed at both broad (island communities) and fine (site communities) spatial scales. The retention of phylogenetic signal in floral traits and the strong influence of these traits on the observed degree of phylogenetic clustering may indicate that pollinators act as a biotic filter for closely related species of Cyrtandra. In contrast, the absence of phylogenetic signal in most leaf traits, coupled with the lower contribution of these traits to niche clustering, suggests that environmental filtering along this trait axis is minimal in the observed communities. This study supports the theory that plant communities are not randomly assembled, and instead, that niche-based processes structure biodiversity at broad and fine spatial scales in diverse congeneric species assemblages.


2021 ◽  
Author(s):  
Sergey Rosbakh ◽  
Loic Chalmandrier ◽  
Shyam Phartyal ◽  
Peter Poschlod

Assembly of plant communities has long been scrutinized through the lens of trait-based ecology. Studies generally analyze functional traits related to the vegetative growth, survival and resource acquisition and thus ignore how ecological processes may affect plants at other stages of their lifecycle, particularly when seeds disperse, persist in soil and germinate. Here, we analyzed an extensive data set of 16 traits for 167 species measured in-situ in 36 grasslands located along an elevational gradient and compared the impact of abiotic filtering, biotic interactions and dispersal on traits reflecting different trait categories: plant vegetative growth, germination, dispersal, and seed morphology. For each community, we quantified community weighted mean (CWM) and functional diversity (FD) for all traits and established their relationships to mean annual temperature. The seed traits were weakly correlated to vegetative traits and thus constituted independent axes of plant phenotypical variation that were affected differently by the ecological processes considered. Abiotic filtering impacted mostly the vegetative traits and to a lesser extent on seed germination and morphological traits. Increasing low-temperature stress towards colder sites selected for short-stature, slow-growing and frost-tolerant species that produce small quantity of smaller seeds with higher degree of dormancy, high temperature requirements for germination and comparatively low germination speed. Biotic interactions, specifically competition in the lowlands and facilitation in uplands, also filtered certain functional traits in the study communities. The benign climate in lowlands promoted plant with competitive strategies including fast growth and resource acquisition (vegetative growth traits) and early and fast germination (germination traits), whereas the effects of facilitation on the vegetative and germination traits were cancelled out by the strong abiotic filtering. The changes in the main dispersal vector from zoochory to anemochory along the gradient strongly affected the dispersal and the seed morphological trait structure of the communities. Specifically, stronger vertical turbulence and moderate warm-upwinds combined with low grazing intensity selected for light and non-round shaped seeds with lower terminal velocity and endozoochorous potential. Synthesis: We clearly demonstrate that, in addition to vegetation traits, seed traits can substantially contribute to functional structuring of plant communities along environmental gradients. Thus, the hard seed traits related to germination and dispersal are critical to detect multiple, complex community assembly rules. Consequently, such traits should be included in core lists of plant traits and, when applicable, be incorporated into analysis of community assembly.


2020 ◽  
Vol 8 ◽  
Author(s):  
Julian Schrader ◽  
Soetjipto Moeljono ◽  
Junus Tambing ◽  
Cornelia Sattler ◽  
Holger Kreft

We introduce a new dataset of woody plants on 60 small tropical islands located in the Raja Ampat archipelago in Indonesia. The dataset includes incidence, abundance and functional trait data for 57 species. All islands were sampled using a standardised transect and plot design providing detailed information on plant occurrences at different spatial scales ranging from the local (plot and transect scale) to the island scale. In addition, the dataset includes information on key plant functional traits linked to species dispersal, resource acquisition and competitive strategies. The dataset can be used to address ecological questions connected to the species-area relationship and community assembly processes on small islands and in isolated habitats. The dataset yields detailed information on plant community structure and links incidence, abundance and functional trait data at different spatial scales. Furthermore, this is the first plant-island dataset for the Raja Ampat archipelago, a remote and poorly studied region, and provides important new information on species occurrences.


2016 ◽  
Author(s):  
Thijs Janzen ◽  
Adriana Alzate ◽  
Moritz Muschick ◽  
Fons van der Plas ◽  
Rampal S. Etienne

ABSTRACTThe African Great Lakes are characterized by an extraordinary diversity of endemic cichlid fish species. The cause of this diversity is still largely unknown. Most studies have tried to solve this question by focusing on macro-evolutionary processes, such as speciation. However, the ecological processes determining local cichlid diversity have so far been understudied, even though knowledge on these might be crucial for understanding larger scale biodiversity patterns.Using trait, environmental and abundance data of cichlid fishes along 36 transects, we have studied how differences in local environmental conditions influence cichlid community assembly in the littoral of Lake Tanganyika, Zambia. We investigated changes in average trait values and in trait-based community assembly processes along three key environmental gradients.Species diversity and local abundance decreased with increasing sand cover and diet-associated traits changed with depth. Analyses on within-community trait diversity patterns indicated that cichlid community assembly was mainly driven by stochastic processes, to a smaller extent by processes that limit the similarity among co-existing species and least by filtering processes that limit the range of species traits occurring in an environment. Despite, the low impact of habitat filtering processes, we find community dissimilarity to increase with increasing environmental difference.Our results suggest that local environmental conditions determine cichlid abundance, while the predominance of stochastic community assembly across all environments explains why the communities with the highest abundances contain most species.


Author(s):  
Michael Kearney ◽  
Melodie McGeoch ◽  
Steven Chown

There is a growing focus on species’ traits in ecology, including initiatives to integrate trait data into biodiversity databases. This focus is motivated in part by a need to develop better predictive capacity for how species respond to environmental change. In this context, one is interested in functional traits – i.e. those with a defined link to environmental variability. This leads immediately to the questions of which traits to prioritise and how to characterise them. Here we argue that this can be achieved with greatest clarity by letting traits be defined by the equations of theoretical models that link individuals to their environments, i.e. mechanistic niche models. We illustrate this approach using the biophysical equations of heat and water exchange, and the metabolic equations of ontogentic growth. From this we derive a schema for a functional trait database that provides a high level of generality and consistency across taxa, and hooks into integrated predictive modelling frameworks. We argue that functional trait attribution at levels above the individual are unhelpful, but discuss how inferences can be made from individual-level functional trait data to populations and species.


2021 ◽  
Vol 9 (4) ◽  
pp. 766
Author(s):  
Christopher J. Ellis ◽  
Johan Asplund ◽  
Renato Benesperi ◽  
Cristina Branquinho ◽  
Luca Di Nuzzo ◽  
...  

Community ecology has experienced a major transition, from a focus on patterns in taxonomic composition, to revealing the processes underlying community assembly through the analysis of species functional traits. The power of the functional trait approach is its generality, predictive capacity such as with respect to environmental change, and, through linkage of response and effect traits, the synthesis of community assembly with ecosystem function and services. Lichens are a potentially rich source of information about how traits govern community structure and function, thereby creating opportunity to better integrate lichens into ‘mainstream’ ecological studies, while lichen ecology and conservation can also benefit from using the trait approach as an investigative tool. This paper brings together a range of author perspectives to review the use of traits in lichenology, particularly with respect to European ecosystems from the Mediterranean to the Arctic-Alpine. It emphasizes the types of traits that lichenologists have used in their studies, both response and effect, the bundling of traits towards the evolution of life-history strategies, and the critical importance of scale (both spatial and temporal) in functional trait ecology.


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