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1.
Whereas most spiders are asocial, species in eight familiesare known to live all their life in communities and are thus"permanent-social." Their special attributes are: tolerance,interattraction, and cooperation. These peculiarities must havebeen achieved step by step several times independently. Periodic-socialspiders have been studied as a link between asocial and permanent-socialspiders. In two familiesthe cribellate Eresidae and ecribellateTheridiidaedifferent steps of periodic sociality havebeen discovered, from brood-care to feeding by regurgitation.The comparative study of the phylogeny of social behavior inboth families uncovers remarkable convergences of patterns fromasocial to permanent-social via periodical-social species ofspiders. 相似文献
2.
Though the primary development of principles of energetics waspioneered in aquatic studies, considerable information has accruedfrom more recent investigations of terrestrial species. Studiesof soil organismsparticularly arthropodshave givenus some understanding of the applicability of principles ofenergetics to terrestrial communities. Data from soil communitieshave yielded an annual energy budget for oribatid mites, ecologicalefficiencies for two trophic levels, and a series of herbivore:carnivoreratios for a number of communities. Energy-flow analyses ofthe problems of species abundance in community organization,the relationship of population production and maintenance, andthe energy relationships of the soil to above-ground communitieshave also been attempted. As data accumulate, however, the inadequacyof the Lindeman model becomes apparent, and there are prospectsfor change in this conceptual scheme. 相似文献
3.
Allelopathy and plant invasions: traditional,congeneric, and bio-geographical approaches 总被引:3,自引:0,他引:3
Inderjit Timothy R. Seastedt Ragan M. Callaway Jarrod L. Pollock Jasleen Kaur 《Biological invasions》2008,10(6):875-890
A relatively small subset of exotic plant species competitively exclude their neighbors in invaded “recipient” communities
but coexist with neighbors in their native habitat. Allelopathy has been argued as one of the mechanisms by which such exotics
may become successful invaders. Three approaches have been used to examine allelopathy as a mechanism for invasion. The traditional
approach examines exotic invasives in the same way that other native plants also suspected of allelopathic activities are
studied. In this approach dose, fate, and replenishment of chemicals can provide powerful evidence for allelopathic processes.
The bio-geographical approach often does not provide as much mechanistic evidence for allelopathy, but comparing the allelopathic
effects of exotic invasives on species from their native and invaded communities yields stronger evidence than the traditional
approach for whether or not allelopathy actually contributes to invasive success. The congeneric, or phylogenetic, approach
involves comparative studies of exotic species with natives in the same genus or that are as closely related as possible.
Congeneric approaches are limited in inference and have been used to study the role of natural enemies in exotic invasion,
but this approach has not been widely used to study allelopathy and invasion. We discuss these three approaches and present
a data set for congeneric Lantana and Prosopis to illustrate how the congeneric approach can be used, and use Centaurea maculosa and (±)-catechin to demonstrate experimentally how traditional and bio-geographic approaches can be integrated to shed light
on allelopathy in exotic plant invasions. 相似文献
4.
Giovanni Bettacchioli Mauro Taormina Fabio Bernini Massimo Migliorini 《Journal of Insect Conservation》2012,16(2):249-261
Studies on disturbance regimes involving carabid beetles have mainly focused on forest habitats. We therefore decided to analyze
the effects of disturbance on carabid communities in a wetland remnant (Lake Chiusi, central Italy). Results highlighted the
presence of a disturbance gradient affecting the species richness and trait-displacement of carabid communities. Carabids
were sampled with pitfall traps from March to October 2008 at nine randomly selected sample stations; a set of landscape attributes
were also collected. Principal Component Analysis (PCA) and generalized linear mixed models (GLMMs) were used to link the
distribution of carabid life-history traits and species richness with the most informative combination of landscape attributes.
The first PCA axis (PC1) showed significant correlation with “distance to the lake shoreline” and “perimeter-area ratio”,
highlighting the presence of a disturbance-axis. The second and third axes accounted only for a trivial portion of the total
variance. GLMMs revealed a progressive decrease in the number of hygrophilous species from the core of the wetland to its
outer areas. Similar trends were observed for species richness and for predator species with good dispersal ability and larval
period in summer. Our results highlight the importance of taking into account community-wide functional implications in landscape
ecology studies. 相似文献
5.
Parasite communities are the product of acquisitions and losses of parasite species during the evolutionary history of their
host. When comparing the parasite communities of different host species to assess the role of ecological variables as determinants
of parasite species richness, a correction must be made for the possible phylogenetic inheritance of parasites from ancestral
hosts independent of host ecology. We performed a comparative analysis of the metazoan ectoparasite communities on the heads
and gills of 111 species of marine fish. The influences of host body size, host schooling behaviour and water temperature
were tested after controlling for both sampling and phylogenetic effects. Overall, water temperature correlated positively
with both parasite species richness and abundance, whereas fish size only correlated with parasite abundance. The correlation
across all fish species between water temperature and parasite species richness was dependent on an outlier point. The results,
however, generally held when fish from different biogeographical areas (Pacific and Atlantic) were analysed separately. In
all analyses, parasite species richness always correlated strongly with parasite abundance. There was no evidence that schooling
fish taxa harboured richer or more abundant ectoparasite communities than their non-schooling sister taxa, possibly because
of the small number of contrasts available for that test. Overall, whereas both water temperature and host size affect the
number of parasite individuals that can be harboured by a fish, only temperature appears important as a determinant of ectoparasite
community richness.
Received: 30 May 1996 / Accepted: 23 October 1996 相似文献
6.
7.
Pontes DS Lima-Bittencourt CI Chartone-Souza E Amaral Nascimento AM 《Journal of industrial microbiology & biotechnology》2007,34(7):463-473
Bacteria account for a major proportion of Earth’s biological diversity. They play essential roles in quite diverse environments
and there has been an increasing interest in bacterial biodiversity. Research using novel and efficient tools to identify
and characterize bacterial communities has been the key for elucidating biological activities with potential for industrial
application. The current approach used for defining bacterial species is based on phenotypic and genomic properties. Traditional
and novel DNA-based molecular methods are improving our knowledge of bacterial diversity in nature. Advances in molecular
biology have been important for studies of diversity, considerably improving our knowledge of morphological, physiological,
and ecological features of bacterial taxa. DNA–DNA hybridization, which has been used for many years, is still considered
the golden standard for bacteria species identification. PCR-based methods investigating 16S rRNA gene sequences, and other
approaches, such as the metagenome, have been used to study the physiology and diversity of bacteria and to identify novel
genes with potential pharmaceutical and other biotechnological applications. We examined the advantages and limitations of
molecular methods currently used to analyze bacterial diversity; these are mainly based on the 16S rRNA gene. These methods
have allowed us to examine microorganisms that cannot be cultivated by routine methods and have also been useful for phylogenetic
studies. We also considered the importance of improvements in microbe culture techniques and how we can combine different
methods to allow a more appropriate assessment of bacterial diversity and to determine their real potential for industrial
applications. 相似文献
8.
This paper examines the functional relationships among species in an Australian rangeland community with mixed life forms.
It follows a previous study (Walker and others 1999) that explored the role of dominant and minor species in maintaining functional
diversity and resilience in a rangeland ecosystem. Unlike our previous results, which were based on estimates of five plant
functional attributes, the dominant species in this second community apparently are functionally no more dissimilar to each
other than to all other species. We suggest that the lack of clear results in mixed life form communities represents a confounding
of the relationships between the “hard” attributes that actually govern how a plant performs in an ecosystem and the “soft”
attributes that we use as surrogates. There are very few data on the hard functional attributes of plant species and consequently
little information on precisely how the (soft) measurable traits are related to their imputed functions. What evidence there
is shows that although the relationships are strong within life forms, they differ between life forms. This poses a problem
for the development of research relating plant biodiversity to ecosystem function. Until such a database is developed, it
will be very difficult to advance our understanding and measurement of functional diversity in mixed life form communities.
Received 30 April 2001; Accepted 23 January 2002. 相似文献
9.
It is often suggested that habitat attributes and interspecific interactions can cause non-random species co-occurrence patterns,
but quantifying their contributions can be difficult. Null models that systematically exclude and include habitat effects
can give information on the contribution of these factors to community assembly. In the boreal forest, saproxylic beetles
are known to be attracted to recently burned forests where they breed in dead and dying trees. We examined whether species
co-occurrences of saproxylic beetles that develop in, and emerge from, boles of recently burned trees show non-random patterns.
We also estimated the extent to which both the post-fire habitat attributes and interspecific interactions among beetles contribute
to such patterns. We sampled tree boles encompassing key attributes (tree species, tree size/dbh and burn severity) that are
thought to characterize species–habitat associations of saproxylic beetles, a proposition that we tested using indicator species
analysis. Two null models with no habitat constraints (“unconstrained”) indicated that a total of 29.4% of the species pairs
tested had significant co-occurrence patterns. Habitat-constrained null models indicated that most of the detected species
aggregations (72%) and segregations (59%) can be explained by shared and distinct species–habitat relationships, respectively.
The assembly pattern was also driven by interspecific interactions, of which some were modulated by habitat; for example,
predator and prey species tended to co-occur in large-sized trees (a proxy of available bark/wood food resource primarily
for the prey). In addition, some species segregation suggesting antagonistic, competitive, or prey–predator interactions were
evident after accounting for the species’ affinities for the same tree species. Overall, our results suggest that an intimate
link between habitat and interspecific interactions can have important roles for community assembly of saproxylic assemblages
even following disturbance by fire. We also show that a systematic application of null models can offer insight into the mechanisms
behind the assembly of ecological communities. 相似文献
10.
Song Learning, Early Nutrition and Sexual Selection in Songbirds 总被引:12,自引:0,他引:12
NOWICKI STEPHEN; PETERS SUSAN; PODOS JEFFREY 《Integrative and comparative biology》1998,38(1):179-190
SYNOPSIS. The developmental processes through which songbirdsacquire their speciestypical songs have been wellstudiedfrom a proximate perspective, but less attention has been givento the ultimate question of why birds learn to sing. We presenta new hypothesis for the adaptive significance of song learningin songbirds, suggesting that this specialized form of vocaldevelopment provides an indicator mechanism by which femalescan accurately assess the quality of potential mates. This hypothesisexpands on the established idea that song can provide an indicatorof male quality, but it explicitly links the variation in songexpression that females use to choose mates to the developmentalprocesses through which song is acquired. How well a male singsreflectedin repertoire size or in other learned features of a male'ssinging behaviorprovides an honest indicator of qualitybecause the timing of song learning and, more importantly, thetiming of the development of brain structures mediating learningcorresponds to a period in development during which young songbirdsare most likely to undergo nutritional stress. This correspondencemeans that song learning can provide a sensitive indicator ofearly developmental history in general, which in turn reflectsvarious aspects of the phenotypic and genotypic quality of apotential mate. 相似文献
11.
Abrams 《Ecology letters》2001,4(2):166-175
In recent years, three related methods have been used to model the phenotypic dynamics of traits under the influence of natural selection. The first is based on an approximation to quantitative genetic recursion equations for sexual populations. The second is based on evolution in asexual lineages with mutation-generated variation. The third method finds an evolutionarily stable set of phenotypes for species characterized by a given set of fitness functions, assuming that the mode of reproduction places no constraints on the number of distinct types that can be maintained in the population. The three methods share the property that the rate of change of a trait within a homogeneous population is approximately proportional to the individual fitness gradient. The methods differ in assumptions about the potential magnitude of phenotypic differences in mutant forms, and in their assumptions about the probability that invasion or speciation occurs when a species has a stable, yet invadable phenotype. Determining the range of applicability of the different methods is important for assessing the validity of optimization methods in predicting the evolutionary outcome of ecological interactions. Methods based on quantitative genetic models predict that fitness minimizing traits will often be evolutionarily stable over significant time periods, while other approaches suggest this is likely to be rare. A more detailed study of cases of disruptive selection might reveal whether fitness-minimizing traits occur frequently in natural communities. 相似文献
12.
Although a widely accepted ecological theory predicts that more diverse plant communities should be better able to capture
resources and turn carbon dioxide into biomass, the most productive communities known are low diversity agricultural ones.
This paradox has fuelled a long running controversy in ecology surrounding the nature of the relationship between diversity,
productivity and fertility. Here, an evolutionary computer model is used which demonstrates that given the opportunity, species-rich
communities may evolve under high fertility conditions. In contrast to low diversity, highly productive agricultural communities
are shown to probably be a recent phenomenon. In simulations where fertility was applied to communities that had evolved under
lower nutrient conditions, a few species had the ability to become ‘dominant’. These species were responsible for the loss
of diversity and for the majority of biomass production. These results are consistent with complementarity theory applying
in nature in old co-evolved low nutrient communities, whereas in recently established fertile agricultural communities, dominant
species appear to regulate biomass production. Understanding the nature of these ‘dominant’ species throws light on our understanding
of phenotypic plasticity and the ecology of invasive species.
The appendices files are currently available at . 相似文献
13.
The abundance and great diversity of life on coral reef ecosystemsprovides many good opportunities for studying the evolutionand specializations of neurophysiological systems and behavior.Crucial stages in the evolution of nervous systems appear tohave occurred in the Precambrian, as revealed in Ediacaran fossilsand their closest living relatives. By the Ordovician, whenChazy "reefs exemplify some of the earliest complex animalcommunities fixed in one place, more elaborate neurologicalmechanisms for orientation, predation, and escape reactionsare indicated. With the evolution offish, the behavioral richnessof reef communities became further enhanced. Elaborate specializationsof feeding, defensive, aggressive, signaling, schooling, andreproductive behaviors are common in fish. Several examplesof behavioral studies on reef organisms are used to illustrateresearch methodologies and the types of conclusions which maybe drawn. These examples include: (1) analysis of symbioticbehavior of an invertebrate and a vertebratesea anemoneand clownfish; (2) signaling behavior of a fishthe sailfishblenny; and (3) a combined electrophysiological and behavioralanalysis of orientation and feeding/attack behaviorsharks.An almost endless number of possibilities for similar analysismakes the organisms of coral reefs especially useful, and challenging,for teaching purposes as well as further research. 相似文献
14.
A total of 18 stream habitats were sampled on the Lower NelsonRiver system within the area bounded by 56°10'50'Nand 93°50'94°50'W, where discontinuous permafrostis present. Thirteen gastropod species were found, with a meancommunity species richness of 3.4. Gastropod richness was adverselyaffected by hydroelectric dams, but was positively correlatedwith macrophyte richness and proportion of clay in the sediments.Some interspecific associations were evident. Species proportionsin communities were related to sediment particle size, whichreflected amount of turbulence. Young were recruited into thepopulations until mid-September. (Received 22 April 1991; accepted 23 September 1991) 相似文献
15.
Recent genetic studies indicate that species with very close phenotypic similarity (“cryptic species”) are a common feature
of nature, and that such cryptic species often coexist in communities. Because traditional views of species coexistence demand
that species differ in phenotype to coexist stably, the existence of sympatric cryptic species appears to challenge traditional
perspectives of coexistence. We evaluated niche diversity in three recently discovered species of Hyalella amphipods that occur sympatrically in lakes and share close phenotypic similarity. We found that, in some cases, these species
exhibited strong complementary spatial distributions within the littoral zone of lakes, both across a distance-from-shore
gradient, and a vertical depth gradient. Additionally, we compared fish stomach contents with habitat samples and found that
species differed in their vulnerability to predation from sunfish (Lepomis spp.). Complementarity among species across axes of spatial distribution and predation risk, two important niche components,
suggests that species with close phenotypic similarity may differ appreciably along ecologically relevant axes. Our results,
considered in the light of previous studies, suggest a community structured by predator-mediated coexistence or sequential
dominance across environmental gradients in the littoral zone. 相似文献
16.
Manuela D'Amen Carsten Rahbek Niklaus E. Zimmermann Antoine Guisan 《Biological reviews of the Cambridge Philosophical Society》2017,92(1):169-187
A fundamental goal of ecological research is to understand and model how processes generate patterns so that if conditions change, changes in the patterns can be predicted. Different approaches have been proposed for modelling species assemblage, but their use to predict spatial patterns of species richness and other community attributes over a range of spatial and temporal scales remains challenging. Different methods emphasize different processes of structuring communities and different goals. In this review, we focus on models that were developed for generating spatially explicit predictions of communities, with a particular focus on species richness, composition, relative abundance and related attributes. We first briefly describe the concepts and theories that span the different drivers of species assembly. A combination of abiotic processes and biotic mechanisms are thought to influence the community assembly process. In this review, we describe four categories of drivers: (i) historical and evolutionary, (ii) environmental, (iii) biotic, and (iv) stochastic. We discuss the different modelling approaches proposed or applied at the community level and examine them from different standpoints, i.e. the theoretical bases, the drivers included, the source data, and the expected outputs, with special emphasis on conservation needs under climate change. We also highlight the most promising novelties, possible shortcomings, and potential extensions of existing methods. Finally, we present new approaches to model and predict species assemblages by reviewing promising ‘integrative frameworks’ and views that seek to incorporate all drivers of community assembly into a unique modelling workflow. We discuss the strengths and weaknesses of these new solutions and how they may hasten progress in community‐level modelling. 相似文献
17.
Leslie Garay‐Narváez Matías Arim José D. Flores Rodrigo Ramos‐Jiliberto 《Oikos》2013,122(8):1247-1253
Human activities have led to massive influxes of pollutants, degrading the habitat of species and simplifying their biodiversity. However, the interaction between food web complexity, pollution and stability is still poorly understood. In this study we evaluate the effect exerted by accumulable pollutants on the relationship between complexity and stability of food webs. We built model food webs with different levels of richness and connectance, and used a bioenergetic model to project the dynamics of species biomasses. Further, we developed appropriate expressions for the dynamics of bioaccumulated and environmental pollutants. We additionally analyzed attributes of organisms’ and communities as determinants of species persistence (stability). We found that the positive effect of complexity on stability was enhanced as pollutant stress increased. Additionally we showed that the number of basal species and the maximum trophic level shape the complexity–stability relationship in polluted systems, and that in‐degree of consumers determines species extinction in polluted environments. Our study indicates that the form of biodiversity and the complexity of interaction networks are essential to understand and project the effects of pollution and other ecosystem threats. 相似文献
18.
Because Australian skinks of the genus Ctenotus display very high local species richness in arid-zone spinifex grasslands but not in mesic habitats, these lizards have been
used as ”model organisms” to ask why ecologically similar taxa coexist under some circumstances but not others. Previous work
has involved detailed studies within small areas, and has looked for differences in ecological processes between arid versus
mesic habitats. We suggest a radically different explanation for the high species-richness of arid-zone Ctenotus, by shifting attention to a larger spatial scale: the regional species pool. Analyses of the geographic distributions of
Ctenotus species confirm that more species coexist at sites in the arid-zone (mean =9.3 species per site) than in other climatic zones
(means 2.4–7.6). However, the total number of species occurring within the arid-zone is actually lower, per km2 of habitat, than is the case in some other climatic zones. That is, arid-zone Ctenotus show a higher local (alpha) species diversity, but a lower regional (gamma) diversity, than their mesic-habitat congeners.
This apparent paradox occurs because most arid-zone species occur over vast areas (mean =1,035,000 km2), whereas congeners from other climatic zones have smaller geographic ranges (200–373,000 km2). The broad distributions of arid-zone taxa reflect the great spatial homogeneity in climatic conditions in this zone. That
is, the ”climate spaces” occupied are similar for Ctenotus species from all bioclimatic regions. Thus, a given amount of climatic space translates into a larger geographic distribution
(and hence, more sympatry) in the arid-zone than in other areas. In summary, the high number of coexisting Ctenotus species in arid-zone habitats may simply reflect the facts that the arid zone is large (so that many species have evolved
therein) and climatically homogeneous (so that any species evolving in that habitat type can disperse very widely, and thus
overlap with many other species). Our approach explains much of the variance in local-assemblage species richness from regional
to site scales; but explanations invoking biological attributes of the species concerned, the nature of their interactions
with other species or with particular resources (such as prey or shelter) may still be significant at microhabitat scales.
For lizard communities in Australia, species richness at a site may be determined more by continental biogeography rather
than by ecological interactions.
Received: 28 June 1999 / Accepted: 14 April 2000 相似文献
19.
Paul M. Magwene 《Evolutionary biology》2008,35(3):191-198
Characterizing and comparing the covariance or correlation structure of phenotypic traits lies at the heart of studies concerned
with multivariate evolution. I describe an approach that represents the geometric structure of a correlation matrix as a type
of proximity graph called a Correlation Proximity graph. Correlation Proximity graphs provide a compact representation of
the geometric relationships inherent in correlation matrices, and these graphs have simple and intuitive properties. I demonstrate
how this framework can be used to study patterns of phenotypic integration by employing this approach to compare phenotypic
and additive genetic correlation matrices within and between species. I also outline a graph-based method for testing whether
an inferred correlation proximity graph is one of a number of possible models that are consistent with a “soft” biological
hypothesis. 相似文献
20.
Experimental Evolution and Its Role in Evolutionary Physiology 总被引:4,自引:2,他引:2
Four general approaches to the study of evolutionary physiologyphylogenetically-basedcomparisons, genetic analyses and manipulations, phenotypicplasticity and manipulation, and selection studiesareoutlined and discussed. We provide an example of the latter,the application of laboratory selection experiments to the studyof a general issue in environmental adaptation, differencesin adaptive patterns of generalists and specialists. A cloneof the bacterium Escherichia coli that had evolved in a constantenvironment of 37°C was replicated into 6 populations andallowed to reproduce for 2,000 generations in a variable thermalenvironment alternating between 32 and 42°C. As predictedby theory, fitness and efficiency of resource use increasedin this new environment, as did stress resistance. Contraryto predictions, however, fitness and efficiency in the constantancestral environment of 37°C did not decrease, nor didthermal niche breadth or phenotypic plasticity increase. Selectionexperiments can thus provide a valuable approach to testinghypotheses and assumptions about the evolution of functionalcharacters. 相似文献