scholarly journals Physiology underlies the assembly of ecological communities

2018 ◽  
Vol 115 (23) ◽  
pp. 6016-6021 ◽  
Author(s):  
Denon Start ◽  
Shannon McCauley ◽  
Benjamin Gilbert
Keyword(s):  
Community Composition ◽  
Species Distributions ◽  
Phenotypic Selection ◽  
Ecological Communities ◽  
Causal Relationships ◽  
Physiological Mechanisms ◽  
Behavioral Traits ◽  
Top Predators ◽  
Species Abundances ◽  
Opposing Effects

Trait-based community ecology promises an understanding of the factors that determine species abundances and distributions across habitats. However, ecologists are often faced with large suites of potentially important traits, making generalizations across ecosystems and species difficult or even impossible. Here, we hypothesize that key traits structuring ecological communities may be causally dependent on common physiological mechanisms and that elucidating these mechanisms can help us understand the distributions of traits and species across habitats. We test this hypothesis by investigating putatively causal relationships between physiological and behavioral traits at the species and community levels in larvae of 17 species of dragonfly that co-occur at the landscape scale but segregate among lakes. We use tools borrowed from phenotypic selection analyses to show that physiological traits underlie activity rate, which has opposing effects on foraging and predator avoidance behaviors. The effect of activity on these behaviors ultimately shapes species distributions and community composition in habitats with either large-bodied fish or invertebrates as top predators. Remarkably, despite the inherent complexity of ecological communities, the expression of just two biomolecules accounts for a high proportion of the variation in behavioral traits and hence, dragonfly community composition between habitats. We suggest that causal relationships among traits can drive species distributions and community assembly.

scholarly journals Distance decay 2.0 – a global synthesis of taxonomic and functional turnover in ecological communities

2021 ◽  
Author(s):  
Caio Graco-Roza ◽  
Sonja Aarnio ◽  
Nerea Abrego ◽  
Alicia T. R. Acosta ◽  
Janne Alahuhta ◽  
...  
Keyword(s):  
Community Composition ◽  
Linear Models ◽  
Distance Decay ◽  
Spatial Distance ◽  
Ecological Communities ◽  
Β Diversity ◽  
Functional Distance ◽  
Holistic Understanding ◽  
Species Abundances ◽  
Rate Of Decay

AbstractUnderstanding the variation in community composition and species abundances, i.e., β-diversity, is at the heart of community ecology. A common approach to examine β-diversity is to evaluate directional turnover in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distances. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 149 datasets comprising different types of organisms and environments. We modelled an exponential distance decay for each dataset using generalized linear models and extracted r2 and slope to analyse the strength and the rate of the decay. We studied whether taxonomic or functional similarity has stronger decay across the spatial and environmental distances. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm, and organismal features. Taxonomic distance decay was stronger along spatial and environmental distances compared with functional distance decay. The rate of taxonomic spatial distance decay was the fastest in the datasets from mid-latitudes while the rate of functional decay increased with latitude. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distances but a higher rate of decay along environmental distances. Marine ecosystems had the slowest rate of decay. This synthesis is an important step towards a more holistic understanding of patterns and drivers of taxonomic and functional β-diversity.

Predator Ecology

2021 ◽  
Author(s):  
John P. DeLong
Keyword(s):  
Food Webs ◽  
Functional Response ◽  
Behavioral Ecology ◽  
Evolutionary Dynamics ◽  
Ecological Systems ◽  
Ecological Communities ◽  
Functional Responses ◽  
Predator Prey ◽  
Top Predators ◽  
Integrative Science

Predator-prey interactions form an essential part of ecological communities, determining the flow of energy from autotrophs to top predators. The rate of predation is a key regulator of that energy flow, and that rate is determined by the functional response. Functional responses themselves are emergent ecological phenomena – they reflect morphology, behavior, and physiology of both predator and prey and are both outcomes of evolution and the source of additional evolution. The functional response is thus a concept that connects many aspects of biology from behavioral ecology to eco-evolutionary dynamics to food webs, and as a result, the functional response is the key to an integrative science of predatory ecology. In this book, I provide a synthesis of research on functional responses, starting with the basics. I then break the functional response down into foraging components and connect these to the traits and behaviors that connect species in food webs. I conclude that contrary to appearances, we know very little about functional responses, and additional work is necessary for us to understand how environmental change and management will impact ecological systems

scholarly journals Trait-mediated trophic cascade creates enemy-free space for nesting hummingbirds

2015 ◽  
Vol 1 (8) ◽  
pp. e1500310 ◽  
Author(s):  
Harold F. Greeney ◽  
M. Rocio Meneses ◽  
Chris E. Hamilton ◽  
Eli Lichter-Marck ◽  
R. William Mannan ◽  
...  
Keyword(s):  
Climate Change ◽  
Habitat Fragmentation ◽  
Breeding Success ◽  
Indirect Effects ◽  
Trophic Cascade ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Ecological Communities ◽  
Top Predators ◽  
Enemy Free Space

The indirect effects of predators on nonadjacent trophic levels, mediated through traits of intervening species, are collectively known as trait-mediated trophic cascades. Although birds are important predators in terrestrial ecosystems, clear examples of trait-mediated indirect effects involving bird predators have almost never been documented. Such indirect effects are important for structuring ecological communities and are likely to be negatively impacted by habitat fragmentation, climate change, and other factors that reduce abundance of top predators. We demonstrate that hummingbirds in Arizona realize increased breeding success when nesting in association with hawks. An enemy-free nesting space is created when jays, an important source of mortality for hummingbird nests, alter their foraging behavior in the presence of their hawk predators.

scholarly journals Phenological variation in annual timing of hibernation and breeding in nearby populations of Arctic ground squirrels

2010 ◽  
Vol 278 (1716) ◽  
pp. 2369-2375 ◽  
Author(s):  
Michael J. Sheriff ◽  
G. Jim Kenagy ◽  
Melanie Richter ◽  
Trixie Lee ◽  
Øivind Tøien ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Ground Squirrels ◽  
Ecological Communities ◽  
Physiological Mechanisms ◽  
Interacting Species ◽  
Trade Offs ◽  
Phenological Shifts ◽  
Arctic Ground Squirrels ◽  
Northern Alaska

Ecologists need an empirical understanding of physiological and behavioural adjustments that animals can make in response to seasonal and long-term variations in environmental conditions. Because many species experience trade-offs between timing and duration of one seasonal event versus another and because interacting species may also shift phenologies at different rates, it is possible that, in aggregate, phenological shifts could result in mismatches that disrupt ecological communities. We investigated the timing of seasonal events over 14 years in two Arctic ground squirrel populations living 20 km apart in Northern Alaska. At Atigun River, snow melt occurred 27 days earlier and snow cover began 17 days later than at Toolik Lake. This spatial differential was reflected in significant variation in the timing of most seasonal events in ground squirrels living at the two sites. Although reproductive males ended seasonal torpor on the same date at both sites, Atigun males emerged from hibernation 9 days earlier and entered hibernation 5 days later than Toolik males. Atigun females emerged and bred 13 days earlier and entered hibernation 9 days earlier than those at Toolik. We propose that this variation in phenology over a small spatial scale is likely generated by plasticity of physiological mechanisms that may also provide individuals the ability to respond to variation in environmental conditions over time.

scholarly journals Idea Paper: improving forecasts of community composition with lightweight biodiversity monitoring across ecological and anthropogenic disturbance gradients

2021 ◽  
Author(s):  
Jamie M. Kass ◽  
Nao Takashina ◽  
Nicholas Friedman ◽  
Buntarou Kusumoto ◽  
Mary E. Blair
Keyword(s):  
Community Composition ◽  
Species Interactions ◽  
Anthropogenic Disturbance ◽  
Ecological Communities ◽  
Geographic Patterns ◽  
Wide Range ◽  
Community Data ◽  
Passive Sensors ◽  
Different Dimensions ◽  
Management And Conservation

Accurate and up-to-date biodiversity forecasts enable robust planning for environmental management and conservation of landscapes under a wide range of uses. Future predictions of the species composition of ecological communities complement more frequently reported species richness estimates to better characterize the different dimensions of biodiversity. The models that make community composition forecasts are calibrated with data on species’ geographic patterns for the present, which may not be good proxies for future patterns. The future establishment of novel communities represents data on species interactions unaccounted for by these models. However, detecting them in a systematic way presents challenges due to the lack of monitoring data for landscapes with high environmental turnover, where such communities are likely to establish. Here, we propose lightweight monitoring over both ecological and anthropogenic disturbance gradients using passive sensors (i.e., those that operate continuously without much human input) to detect novel communities with the aim of updating models that make community composition forecasts. Monitoring over these two gradients should maximize detection of novel communities and improve understanding of relationships between community composition and environmental change. Further, barriers regarding cost and effort are reduced by using relatively few sensors requiring minimal upkeep. Ongoing updates to community composition forecasts based on novel community data and better understanding of the associated uncertainty should improve future decision-making for both resource management and conservation efforts.

scholarly journals Trophic niches, diversity and community composition of invertebrate top predators (Chilopoda) as affected by conversion of tropical lowland rainforest in Sumatra (Indonesia)

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0180915 ◽  
Author(s):  
Bernhard Klarner ◽  
Helge Winkelmann ◽  
Valentyna Krashevska ◽  
Mark Maraun ◽  
Rahayu Widyastuti ◽  
...  
Keyword(s):  
Community Composition ◽  
Tropical Lowland ◽  
Top Predators ◽  
Lowland Rainforest ◽  
Trophic Niches ◽  
Tropical Lowland Rainforest

Factors Influencing the Distribution of Phytoplankton in 97 Headwater Lakes in Insular Newfoundland

1987 ◽  
Vol 44 (3) ◽  
pp. 639-649 ◽  
Author(s):  
J. C. Earle ◽  
H. C. Duthie ◽  
David A. Scruton
Keyword(s):  
Environmental Factors ◽  
Species Distributions ◽  
Factors Influencing ◽  
Headwater Lakes ◽  
Species Abundances ◽  
Selected Subset ◽  
Highly Correlated ◽  
Linkage Cluster ◽  
Complete Linkage Cluster ◽  
Lake Size

Phytoplankton samples collected from 97 headwater lakes throughout insular Newfoundland were analyzed and used as a basis for a statistical evaluation of the environmental factors influencing species distributions. A selected subset of 77 taxa were clustered using a complete-linkage cluster analysis. The final 12 clusters represent the associations of species found occurring together in insular Newfoundland. Physical, chemical, and morphometric data collected with the phytoplankton served to characterize the environment. Factor analysis simplified the original variables, many of which were highly correlated and uninterpretable, into seven derived environmental factors: dystrophy, hardness, salinity, lake size, season, watershed influence, and orthophosphate enrichment. The resulting orthogonally rotated (VARIMAX) scores comprising these seven factors were correlated with species abundances. Spearman correlations showed several relationships between species distributions and the seven derived environmental factors. Although the analysis identified a subset of naturally acidic, dystrophic lakes, it failed to reveal any evidence of anthropogenic acidification in the lakes studied. For the most part, the members from each of the cluster groups demonstrated similar relationships with the derived environmental factors. The evidence suggests that the cluster groups may represent species associations; groups of species that co-occur because of their common requirements for specific environmental conditions. Phytoplankton autecological findings resulting from this study of insular Newfoundland lakes correspond well with conclusions derived independently from a comparable study of 95 headwater lakes in Labrador.

scholarly journals Remembrance of things past: modelling the relationship between species' abundances in living communities and death assemblages

2011 ◽  
Vol 8 (1) ◽  
pp. 131-134 ◽  
Author(s):  
Thomas D. Olszewski
Keyword(s):  
Half Life ◽  
Species Differences ◽  
Species Abundance ◽  
Time Averaging ◽  
Ecological Communities ◽  
Post Mortem ◽  
Death Assemblages ◽  
Species Abundances ◽  
The Relationship ◽  
Range Of Variation

Accumulations of dead skeletal material are a valuable archive of past ecological conditions. However, such assemblages are not equivalent to living communities because they mix the remains of multiple generations and are altered by post-mortem processes. The abundance of a species in a death assemblage can be quantitatively modelled by successively integrating the product of an influx time series and a post-mortem loss function (a decay function with a constant half-life). In such a model, temporal mixing increases expected absolute dead abundance relative to average influx as a linear function of half-life and increases variation in absolute dead abundance values as a square-root function of half-life. Because typical abundance distributions of ecological communities are logarithmically distributed, species' differences in preservational half-life would have to be very large to substantially alter species' abundance ranks (i.e. make rare species common or vice-versa). In addition, expected dead abundances increase at a faster rate than their range of variation with increased time averaging, predicting greater consistency in the relative abundance structure of death assemblages than their parent living community.

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