scholarly journals Forbidden links, trait matching and modularity in plant-hummingbird networks: Are specialized modules characterized by higher phenotypic floral integration?

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10974
Author(s):  
Jaume Izquierdo-Palma ◽  
Maria del Coro Arizmendi ◽  
Carlos Lara ◽  
Juan Francisco Ornelas
Keyword(s):  
Species Coexistence ◽  
Niche Partitioning ◽  
Modular Organization ◽  
Minor Role ◽  
Biological Processes ◽  
Generalist Species ◽  
Tropical Plant ◽  
Plant Assemblage ◽  
Morphological Specialization ◽  
Understory Plant

Background Plant-pollinator mutualistic networks show non-random structural properties that promote species coexistence. However, these networks show high variability in the interacting species and their connections. Mismatch between plant and pollinator attributes can prevent interactions, while trait matching can enable exclusive access, promoting pollinators’ niche partitioning and, ultimately, modularity. Thus, plants belonging to specialized modules should integrate their floral traits to optimize the pollination function. Herein, we aimed to analyze the biological processes involved in the structuring of plant-hummingbird networks by linking network morphological constraints, specialization, modularity and phenotypic floral integration. Methods We investigated the understory plant-hummingbird network of two adjacent habitats in the Lacandona rainforest of Mexico, one characterized by lowland rainforest and the other by savanna-like vegetation. We performed monthly censuses to record plant-hummingbird interactions for 2 years (2018–2020). We also took hummingbird bill measurements and floral and nectar measurements. We summarized the interactions in a bipartite matrix and estimated three network descriptors: connectance, complementary specialization (H2’), and nestedness. We also analyzed the modularity and average phenotypic floral integration index of each module. Results Both habitats showed strong differences in the plant assemblage and network dynamics but were interconnected by the same four hummingbird species, two Hermits and two Emeralds, forming a single network of interaction. The whole network showed low levels of connectance (0.35) and high specialization (H2’ = 0.87). Flower morphologies ranged from generalized to specialized, but trait matching was an important network structurer. Modularity was associated with morphological specialization. The Hermits Phaethornis longirostris and P. striigularis each formed a module by themselves, and a third module was formed by the less-specialized Emeralds: Chlorestes candida and Amazilia tzacatl. The floral integration values were higher in specialized modules but not significantly higher than that formed by generalist species. Conclusions Our findings suggest that biological processes derived from both trait matching and “forbidden” links, or nonmatched morphological attributes, might be important network drivers in tropical plant-hummingbird systems while morphological specialization plays a minor role in the phenotypic floral integration. The broad variety of corolla and bill shapes promoted niche partitioning, resulting in the modular organization of the assemblage according to morphological specialization. However, more research adding larger datasets of both the number of modules and pollination networks for a wider region is needed to conclude whether phenotypic floral integration increases with morphological specialization in plant-hummingbird systems.

scholarly journals Multi-scale phenological niches in diverse Amazonian plant communities

2021 ◽  
Author(s):  
Damie Pak ◽  
Varun Swamy ◽  
Patricia Alvarez-Loayza ◽  
Fernando Cornejo ◽  
Simon A. Queenborough ◽  
...  
Keyword(s):  
Plant Communities ◽  
Species Coexistence ◽  
Niche Partitioning ◽  
Fruit Production ◽  
Reproductive Phenology ◽  
Positive Interactions ◽  
Temporal Scales ◽  
Tropical Plant ◽  
Wide Range ◽  
Environmental Responses

Phenology has long been hypothesized as an avenue for niche partitioning or interspecific facilitation, both promoting species coexistence. Tropical plant communities exhibit striking diversity in reproductive phenology, including seasonal patterns of fruit production. Here we study whether this phenological diversity is non-random, what are the temporal scales of phenological patterns, and ecological factors that drive reproductive phenology. We applied multivariate wavelet analyses to test for phenological synchrony versus compensatory dynamics (i.e. anti-synchronous patterns where one species' decline is compensated by the rise of another) among species and across temporal scales. We used data from long-term seed rain monitoring of hyperdiverse plant communities in the western Amazon. We found significant synchronous whole-community phenology at a wide range of time scales, consistent with shared environmental responses or positive interactions among species. We also observed both compensatory and synchronous phenology within groups of species likely to share traits (confamilials) and seed dispersal mechanisms. Wind-dispersed species exhibited significant synchrony at ~6 mo scales, suggesting these species share phenological niches to match seasonality of wind. Our results indicate that community phenology is shaped by shared environmental responses but that the diversity of tropical plant phenology partly results from temporal niche partitioning. The scale-specificity and time-localized nature of community phenology patterns highlights the importance of multiple and shifting drivers of phenology.

scholarly journals Species coexistence and overlapping distributions in a metacommunity are compatible with niche differences and competition at a local scale

2020 ◽  
Author(s):  
Maxime Dubart ◽  
Patrice David ◽  
Frida Ben-Ami ◽  
Christoph R. Haag ◽  
V. Ilmari Pajunen ◽  
...  
Keyword(s):  
Species Coexistence ◽  
Scale Up ◽  
Niche Partitioning ◽  
Niche Differentiation ◽  
Apparent Paradox ◽  
Extinction Rates ◽  
Interspecific Differences ◽  
Baltic Coast ◽  
Species Specific

AbstractNiche partitioning is the most studied factor structuring communities of competing species. In fragmented landscapes, however, a paradox can exist: different taxa may competitively dominate different types of habitat patches, resulting in a form of spatial niche partitioning, yet differences in long-term distributions among species can appear surprisingly small. This paradox is illustrated by an emblematic metacommunity - that of Daphnia spp. in rockpools on the Finnish Baltic coast, where three species compete with each other, have distinct ecological preferences, yet largely overlap in long-term distributions. Here we examine how metacommunity models that explicitly estimate species-specific demographic parameters can solve the apparent paradox. Our research confirms previous studies that local extinction rates are influenced by environmental variables in a strong and species-specific way and are considerably increased by interspecific competition. Yet, our simulations show that this situation exists alongside interspecific differences in realized niches that are, overall, small, and identified three main explanations for this compatibility. Our results illustrate how state-space modelling can clarify complex metacommunity dynamics and explain why local competition and niche differentiation do not always scale up to the landscape level.

Co-occurrence patterns of rodents at multiple spatial scales: competitive release of generalists following habitat loss?

2019 ◽  
Vol 100 (4) ◽  
pp. 1229-1242 ◽  
Author(s):  
Thomas Püttker ◽  
Camila S Barros ◽  
Bruno T Pinotti ◽  
Adriana A Bueno ◽  
Renata Pardini
Keyword(s):  
Habitat Loss ◽  
Spatial Scales ◽  
Niche Partitioning ◽  
Large Data ◽  
Data Set ◽  
Generalist Species ◽  
Competitive Release ◽  
Spatial Niche ◽  
Habitat Generalist ◽  
Occurrence Patterns

AbstractTheory predicts that habitat generalist species are excluded by specialist species in optimal habitat for specialists, and empirical data commonly show a shift from specialist- to generalist-dominated communities following disturbance. We investigated co-occurrence patterns of habitat generalist and specialist terrestrial rodents at two spatial scales in the Atlantic Forest, aiming at evaluating the following hypotheses: 1) within-patch spatial niche partitioning promotes coexistence of generalists and specialists, leading to checkerboard presence-absence patterns at small (within-patch) rather than large (among-patch) scales; and 2) the decrease in abundance of specialists due to habitat loss promotes a competitive release of generalists, leading to negative covariance in abundance between generalists and specialists among patches. Drawing on a large data set including 363 sites within three patches in continuous forest, and 45 patches within three landscapes, we used C-scores based on presence-absence and abundance data to evaluate spatial segregation. We found consistent segregation between specialists and generalists at the within-patch rather than among-patch scale, but no consistent negative covariance in abundance between generalists and specialists among patches (as covarying species pairs varied across landscapes). Our findings suggest that spatial patterns caused by competition are scale-dependent, and coexistence of generalists and specialists is promoted by within-patch spatial niche partitioning. However, the influence of competitive release on the proliferation of generalists may be outweighed by other factors in fragmented landscapes.A teoria ecológica prevê que espécies generalistas de habitat são excluídas por espécies especialistas em hábitats ótimos para as especialistas, e dados empíricos comumente mostram uma mudança de dominância das comunidades - de especialistas para generalistas - após distúrbios. Nós investigamos os padrões de coocorrência de roedores terrestres generalistas e especialistas de habitat em duas escalas espaciais na Mata Atlântica, para testar as seguintes hipóteses: 1) a partição espacial do nicho dento de fragmentos promove a coexistência de generalistas e especialistas, levando a padrões de presença-ausência “tabuleiro de damas” em escalas pequenas (dentro de fragmento) mas não em escalas grandes (entre fragmentos); 2) a diminuição da abundância de especialistas devido à perda de habitat promove uma liberação competitiva de generalistas, levando a covariância negativa da abundância de generalistas e especialistas entre fragmentos. A partir de um grande banco de dados - 363 sítios dentro de três fragmentos de floresta contínua, e 45 fragmentos dentro de três paisagens, usamos C-scores baseados em dados de presença/ausência e abundância para avaliar a segregação espacial. Encontramos segregação consistente entre especialistas e generalistas na escala menor (dentro de fragmentos) e não na maior (entre fragmentos), mas não encontramos covariância negativa na abundância de generalistas e especialistas entre fragmentos (dado que os pares de espécies que covariaram mudou entre as paisagens). Nossos resultados sugerem que padrões espaciais causados por competição são dependentes de escala, e que a coexistência de generalistas e especialistas é promovida pela partição espacial de nicho dentro dos fragmentos. No entanto, a influência da liberação competitiva na proliferação de generalistas pode ser superada por outros fatores em paisagens fragmentadas.

Niche partitioning and species coexistence in a Neotropical felid assemblage

2010 ◽  
Vol 36 (4) ◽  
pp. 403-412 ◽  
Author(s):  
Mario S. Di Bitetti ◽  
Carlos D. De Angelo ◽  
Yamil E. Di Blanco ◽  
Agustín Paviolo
Keyword(s):  
Species Coexistence ◽  
Niche Partitioning

Acoustic niche partitioning in five Cuban frogs of the genus Eleutherodactylus

2019 ◽  
Vol 40 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Irelis Bignotte-Giró ◽  
Ansel Fong G. ◽  
Germán M. López-Iborra
Keyword(s):  
Species Coexistence ◽  
Niche Partitioning ◽  
Sympatric Species ◽  
Egg Laying ◽  
Signal Frequency ◽  
Time Signal ◽  
Time Frequency ◽  
Sound Communication ◽  
Acoustic Niche ◽  
Single Genus

Abstract Acoustic segregation is a way to reduce competition and allows for species coexistence within anuran communities. Thus, separation in at least one acoustic niche dimension is expected, which also contributes to achieving effective communication among frogs. Here we studied an assemblage of five terrestrial egg-laying anuran species, all in the genus Eleutherodactylus, in a montane rainforest in eastern Cuba. Our aim was to determine if partitioning exists between these species in any dimension (time, signal frequency or space) of the acoustic niche. The studied assemblage had the following characteristics: (1) there was one diurnal species, two species with calling activity throughout the day and two species that call at night; (2) only two species overlapped in call frequencies and most had different calls, both in terms of dominant frequencies and in temporal characteristics; and (3) males of the species that overlapped in vocalizing time or signal frequency used different calling microhabitats or heights. This study provides evidence for the acoustic niche hypothesis in anurans, showing low probabilities of interference in sound communication among these frogs. The five species were separated in at least one of the three acoustic dimensions (calling time, frequency and site) as it occurs in mainland communities with more sympatric species of several genera. Conversely, species in single-genus communities studied in Puerto Rico overlapped completely in calling times. This seems to be due to the higher number of sympatric species at our site.

scholarly journals Reproductive interference hampers species coexistence despite conspecific sperm precedence

2018 ◽  
Author(s):  
Ryosuke Iritani ◽  
Suzuki Noriyuki
Keyword(s):  
Mathematical Model ◽  
Related Species ◽  
Species Coexistence ◽  
Niche Partitioning ◽  
Reproductive Interference ◽  
Food Sources ◽  
Comparative Approach ◽  
Sperm Precedence ◽  
Interspecific Mating ◽  
Closely Related Species

AbstractNegative interspecific mating interactions, known as reproductive interference, can hamper species coexistence in a local patch and promote niche partitioning or geographical segregation of closely related species. Conspecific sperm precedence (CSP), which occurs when females that have mated with both conspecific and heterospecific males preferentially use conspecific sperm for fertilization, might contribute to species coexistence by mitigating the costs of interspecific mating and hybridization. We examined whether two closely related species exhibiting CSP can coexist in a local environment in the presence of reproductive interference. First, using a behaviourally explicit mathematical model, we demonstrated that two species characterized by negative mating interactions are unlikely to coexist because the costs of reproductive interference, such as loss of mating opportunity with conspecific partners, are inevitably incurred when individuals of both species are present. Second, we experimentally demonstrated differences in mating activity and preference in twoHarmonialadybird species known to exhibit CSP. According to the developed mathematical model of reproductive interference, these behavioural differences should lead to local extinction ofH. yedoensisbecause of reproductive interference byH. axyridis. This prediction is consistent with field observations thatH. axyridisuses various food sources and habitats whereasH. yedoensisis confined to a less preferred prey item and a pine tree habitat. Finally, by a comparative approach, we showed that niche partitioning or parapatric distribution, but not sympatric coexistence in the same habitat, is maintained between species with CSP belonging to a wide range of taxa, including vertebrates and invertebrates living in aquatic or terrestrial environments. Taken together, these results lead us to conclude that reproductive interference generally destabilizes local coexistence even in closely related species that exhibit CSP.

Predation defeats competition on the seafloor

Paleobiology ◽  
2008 ◽  
Vol 34 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Steven M. Stanley
Keyword(s):  
Competitive Exclusion ◽  
Niche Partitioning ◽  
Large Body ◽  
Minor Role ◽  
Time Of Arrival ◽  
Ecological Communities ◽  
Competition Theory ◽  
Essential Resource ◽  
Primary Focus ◽  
A Minor

… the snail, whose tender horns being hit Shrinks backward in his shelly cave with pain, And there, all smothered up, in shade doth sit, Long after fearing to creep forth again….— William Shakespeare, Venus and Adonis (1593)For many decades, ecology textbooks presented classical competition theory without reservation. The central principle here is that two species sharing an essential resource that is in limited supply cannot coexist for long because the competitively superior species will eliminate the other one. The implication is that ecological communities should be characterized by division of resources among species, or niche partitioning. Thus, it is understandable that many paleontologists have continued to invoke concepts of competitive exclusion and niche partitioning in their studies of ancient guilds and communities. By now, however, there is a large body of neontological literature demonstrating that interspecific competition and resource partitioning play only a minor role in many ecological communities—especially benthic marine communities, which are the primary focus of the following discussion. Predation and physical disturbance inflict so much damage on biotas of the seafloor that populations of one species seldom monopolize a potentially limiting resource, except sporadically and locally. As a result, it is uncommon for any species to drive another to extinction through competitive exclusion—or even to force another species to drastically change its exploitation of any environmental resource throughout its geographic range. Furthermore, what particular species or group of species occupies a particular microhabitat is often simply a matter of time of arrival.

scholarly journals Reproductive Interference and Niche Partitioning in Aphidophagous Insects

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Suzuki Noriyuki ◽  
Naoya Osawa
Keyword(s):  
Species Coexistence ◽  
Resource Competition ◽  
Habitat Preferences ◽  
Niche Partitioning ◽  
Reproductive Interference ◽  
Species Pairs ◽  
Specialist Species ◽  
Race Formation

The range and quality of prey species differ greatly among closely related species of predators. However, the factors responsible for this diversified niche utilization are unclear. This is because the predation and resource competition do not always prevent species coexistence. In this paper, we present evidence in support of reproductive interference as a driver of niche partitioning, focusing on aphidophagous insect. Firstly, we present closely related generalist and specialist species pairs in aphidophagous lacewings to compare the reproductive interference hypothesis with two other hypotheses that have been proposed to explain niche partitioning in lacewings and sympatric speciation through host race formation and sexual selection. Secondly, we present a case study that shows how reproductive interference can drive niche partitioning in sibling ladybird species. Thirdly, we show that many ladybird genera include species inhabiting the same region but having different food and habitat preferences, raising the possibility that reproductive interference might occur in these groups. Finally, we show that intraguild predation cannot always explain the niche partitioning in aphidophagous insects including hoverflies and parasitoids. On the basis of the evidence presented, we urge that future studies investigating predator communities should take account of the role of reproductive interference.

scholarly journals Understanding the value of plant diversity for ecosystem functioning through niche theory

2016 ◽  
Vol 283 (1844) ◽  
pp. 20160536 ◽  
Author(s):  
Lindsay A. Turnbull ◽  
Forest Isbell ◽  
Drew W. Purves ◽  
Michel Loreau ◽  
Andy Hector
Keyword(s):  
Plant Diversity ◽  
Real World ◽  
Ecosystem Functioning ◽  
Species Coexistence ◽  
Future Research ◽  
Biological Processes ◽  
Niche Theory ◽  
Natural Ecosystems ◽  
Empirical Results ◽  
Simple Mapping

Biodiversity experiments have generated robust empirical results supporting the hypothesis that ecosystems function better when they contain more species. Given that ecosystems provide services that are valued by humans, this inevitably suggests that the loss of species from natural ecosystems could diminish their value. This raises two important questions. First, will experimental results translate into the real world, where species are being lost at an alarming rate? And second, what are the benefits and pitfalls of such valuation exercises? We argue that the empirical results obtained in experiments are entirely consistent with well-established theories of species coexistence. We then examine the current body of work through the lens of niche theory and highlight where closer links with theory could open up opportunities for future research. We argue that niche theory predicts that diversity–functioning relationships are likely to be stronger (and require more species) in the field than in simplified experimental settings. However, we caution that while many of the biological processes that promote coexistence can also generate diversity–function relationships, there is no simple mapping between the two. This implies that valuation exercises need to proceed with care.

scholarly journals Epistasis from functional dependence of fitness on underlying traits

2012 ◽  
Vol 279 (1745) ◽  
pp. 4156-4164 ◽  
Author(s):  
Hsuan-Chao Chiu ◽  
Christopher J. Marx ◽  
Daniel Segrè
Keyword(s):  
General Expression ◽  
Biological Networks ◽  
Functional Dependence ◽  
System Level ◽  
Modular Organization ◽  
Mechanistic Models ◽  
Negative Bias ◽  
Biological Processes ◽  
The Difference ◽  
Complex Architecture

Epistasis between mutations in two genes is thought to reflect an interdependence of their functions. While sometimes epistasis is predictable using mechanistic models, its roots seem, in general, hidden in the complex architecture of biological networks. Here, we ask how epistasis can be quantified based on the mathematical dependence of a system-level trait (e.g. fitness) on lower-level traits (e.g. molecular or cellular properties). We first focus on a model in which fitness is the difference between a benefit and a cost trait, both pleiotropically affected by mutations. We show that despite its simplicity, this model can be used to analytically predict certain properties of the ensuing distribution of epistasis, such as a global negative bias, resulting in antagonism between beneficial mutations, and synergism between deleterious ones. We next extend these ideas to derive a general expression for epistasis given an arbitrary functional dependence of fitness on other traits. This expression demonstrates how epistasis relative to fitness can emerge despite the absence of epistasis relative to lower level traits, leading to a formalization of the concept of independence between biological processes. Our results suggest that epistasis may be largely shaped by the pervasiveness of pleiotropic effects and modular organization in biological networks.

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