Guild Concept Research Articles

Guild structure of stored grain insects reflects food resource availability in tropical forest ecosystems

The Guild concept has been of great interest to ecologists, and widely applied in entomology, particularly to study the activity of insects in various ecosystems. However, the guild concept in storage entomology is understudied. We hypothesized that the feeding guild structure of stored grain insect (SGI) community changes with different food resources available. In the present study, we examined the community structure of insects in the tribal grain storage system. Further, we established a classification system for the stored grain insect species based on their food resource exploitation pattern and the role of associated factors involved in the spatial and temporal structure of the SGI community. The species richness showed that cereal feeder was dominated in tribal grain storage system, abundance varied greatly, and high number of pulse feeders reflect the availability of resources. Further, it shows non-significant association among the number of species in each feeder community at different altitudes of the study area and SGI from different feeding guilds were randomly distributed, however, congregated more on their preferred food sources.

Species from the viewpoint of biocoenology

Some questions of the use of the “species” concept in biocoenology and hydrobiology are considered. The existence of certain difficulties and ambiguities in the use of this concept is shown. It is proposed to clarify the goals and objectives of identifying the species structure of biocoenoses. The examples show that ecomorphs and coeno-ecomorphs are not less important elements of a biocenotic system and require thorough research. The question of the possibility and feasibility of definitions "to species level" of all members of the community is considered. The ecological niche concept is associated with species, although there is also the guild concept that unites species according to the principle of convergent similarity of trophic, topical, or other preferences. Various systems of bioindication have become widespread, which are based on the principle of compliance of a particular species population to certain conditions. First of all, we are talking about disturbed conditions, including various impacts by pollution. It was shown that not only species, but also more easily identifiable higher taxa could be used as bioindicators of certain conditions.

The closed academy? Guild power and academic social class

AbstractAcademic inbreeding is a deeply ingrained practice which needs to be understood by reference to the medieval guilds. Drawing on the guild concept and associated benefits of forms of capital, a distinction is drawn between ‘guild‐route’ academics who have followed a privileged, linear path into academe and their ‘non‐guild’ counterparts who tend to enter later in their career from the professions or industry, often without a PhD. The tendency to represent early career researchers from a guild background as members of an academic proletariat is largely misleading and fails to take account of their privileged entrée into academe. Their experience is contrasted with those recruited via the non‐guild route who do not have the benefits of the valued social, cultural or symbolic capital needed to advance their careers. Policy implications are discussed to better understand the effects of academic social class on recruitment practices in universities.

El concepto de gremio: del feudalismo a la ecología de comunidades

Se analiza el origen y evolución del término gremio, así como su aplicación en ecología, considerando las múltiples connotaciones que se le ha dado y la confusión que se ha generado por utilizarlo de forma indebida. De igual forma, se discute la importancia de homogenizar los términos y definir de manera clara a los gremios, a fin de tener un leguaje que permita entender los alcances del término sin ambigüedades. El uso del término, así como su persistencia en estudios ecológicos, sugiere que el mismo tiene relevancia considerable dependiendo de la forma y el modo en que es empleado. El uso inadecuado o derivado de este término es arriesgado y peligroso, dado que tiende a reducir el término a una palabra vacía con múltiples significados. Más que nada, esta trivialización constituye una amenaza al uso y significado adecuado del concepto de gremio en ecología.

Expanding the trait-based concept of benthic diatoms: Development of trait- and species-based indices for conductivity as the master variable of ecological status in continental saline lakes

Shallow, saline inland lakes occur over large areas in Central-Europe and they bear exceptionally high biological conservation values. Climate change and anthropogenic activities threaten their natural conditions, or even their existence. These aquatic ecosystems are exposed to multiple stress like naturally high conductivity, pH and nutrient load with very low transparency for light. As they are subjects of criteria set by the EC Water Framework Directive and biological conservation managment, there is an urgent need for developing a suitable quality index for their ecological status assessment. As one major Biological Quality Element, benthic diatoms may provide a reliable basis for their ecological status indication. Here, in a large data set covering the soda lakes of the Carpathian basin, we developed a species- and a trait-based diatom ecological status index. First, based on the weighted average method, we developed a type specific, species-based diatom index (DISP = Diatom Index for Soda Pans) using conductivity as master variable of environmental constrains; and therefore the ecological status in soda lakes. Furthermore, by adapting and improving further the widely-used diatom ecological guild concept, we also developed an alternative trait-based index, which helps avoiding some limitations arising from the obvious complexity of the taxonomy-based approach. Our DISP index covered a significantly larger species pool for index calculation, and responded to conductivity in a more reliable way compared to other available indices. In the trait-based index (TBI) motility, small cell size, and less roundish, more elongated shape as functional and morphological traits indicated pristine ecological conditions (i.e high conductivity) of the soda pans. Planktic life form, high and low ecological guild profiles, as well as the large cell size indicated worse ecological conditions (e.g. lower conductivity). Our study highlights that benthic diatoms provide a reliable basis for ecological status assessment in soda lakes. While both the taxonomic and the functional trait approaches performed well in our analysis, the success of the trait-based approach may enable the use of our TBI index in biomonitoring and conservation management of soda lakes outside of the Carpathian basin, independently of the geographic location.

Trophic guild concept: factors affecting within‑guild consistency for tropical estuarine fish

The trophic guild concept has proved useful in distilling the diverse feeding inter-actions displayed by fish in temperate estuaries into a standardised subset that simplifies the application of trophic information to management. However, the high species richness displayed by tropical flora and fauna introduces the potential for feeding diversity within presumed guilds, potentially reducing the value of the standard guild concept. We evaluated within-guild consistency for a group of tropical estuarine fish species comprising a presumably coherent trophic zoobenthivore feeding guild (i.e. fish that feed primarily on zoobenthic prey) within 10 estuarine systems in tropical northeastern Australia. The zoobenthivore assemblage did not form a single coherent trophic group, rather the different components of the zoobenthivore guild responded to the broad spectrum of available prey in distinctly different ways. Some species displayed quite general diets while others fed principally on particular types of zoobenthic prey. The distinct prey specialisations often lead to different members of the presumed guild participating in different food chain pathways within the estuarine food web. As a result, substantial and important trophic differences would be masked if these disparate components were aggregated into a single trophic guild. While simplifications can be valuable, and often necessary, in data-poor situations, the complexity uncovered in this study emphasises that caution is required in applying a broad simplified scheme such as the guild concept to specific situations. Caution must be used when applying a guild approach that imports interpretation from other species and/or locations and should be explicitly recognised as an interim position until more specific data can be acquired.

Quo vadis universitas

The article considers the advantages and disadvantages of the European universities that can be explained only by the analysis of their history. In contrast to the conventional theories, the economic enforcement was the driving cause for university formation in the Middle Ages. The guild concept created by Siegfried Bar 15 years ago explains the historical imperative, but also the construction faults of the universities resulting from their specific features essentially the principles of self-autonomy and cooptation. The faults of university organization are the main reasons why nearly all university reforms failed. There does not exist any convincing proof that the introduction of new organization models such as bachelor and master degree courses or excellence clusters are of more efficiency in teaching and research. The international university ranking did not change in recent years; the top ten universities are still located in the USA and Great Britain. The majority of German universities range between the middle and the end of the ranking list. It is demonstrated that the main causes of this discrepancy are the delay of academic qualification, the lack of competition, the dependency of the public policy, and the insufficient financial support. Progress in university research and teaching can be obtained only if these problems can be solved.

Bird guild loss and its determinants on subtropical land-bridge islands, China

BackgroundThe guild concept is useful for understanding the community structure in a land-bridge island system, but most fragmentation studies have focused only on the importance of island area and isolation, other island attributes such as perimeter-area ratio (PAR) were overlooked or understudied.MethodsWe have adopted a guild approach to investigate the impacts of island attributes on bird guild richness on a set of 41 recently isolated land-bridge islands in the Thousand Island Lake (TIL), China.ResultsWe found insectivores had the largest number of species (34 species), followed by understory foraging guilds (28 species), omnivores (27 species) and canopy guilds (25 species). Furthermore, our data showed that migrants and residents responded equally to island area, insectivores and understory guilds were sensitive to island area but omnivores and canopy guilds were not very sensitive. Most guild richness was determined by island area, except for omnivores and canopy guilds.ConclusionsAlthough PAR or habitat diversity found to be important for bird species richness, our results highlight the importance of island area in maintaining bird diversity in fragmented island systems.

Moving beyond the guild concept: developing a practical functional trait framework for terrestrial beetles

1. New logical and analytical frameworks for studying functional traits have led to major advances in plant and freshwater ecology at local and global scales. The ecological and taxonomic diversity of terrestrial adult beetles (Coleoptera) means that functional trait approaches should have considerable power to illuminate the function not only of these animals but also of the ecosystems in which they occur.2. Even though the functional trait concept is not new in ecology, it is still plagued with inconsistencies in methodology and terminology. Plant‐based studies have shown that an integrated and relatively consistent functional trait approach facilitates comparisons between studies, and allows the full utility and predictive capacity of trait‐based approaches to be realised.3. This review outlines a logical framework for adult beetle functional trait studies using uniform terminology and methodology similar to those used by plant ecologists. Beetle life‐history and ecomorphological trait studies are synthesised and it is shown that a combination of both is analogous to the functional trait approach. A general functional trait list for beetles and potential functional links is outlined, as are potential analysis approaches. A consistent functional trait approach, coupled with advances in molecular techniques, has the capability to provide deeper insights into beetle community assembly and how beetles impact ecosystems and will enable worldwide comparisons and predictions to be made.

Variability of mesohabitat characteristics in riffle‐pool reaches: Testing an integrative evaluation concept (FGC) for MEM‐application

AbstractThis paper investigates the variability of mesohabitat characteristics in various riffle‐pool reaches. The tested river sections (n = 13) feature clear variation in slope (0.0004–0.0132) and low flow discharge (0.05–915 m3s−1) in different river types (straight to meandering). Mesohabitat characteristics (water depth, flow velocity, bottom shear stress) were calibrated according to the MEM‐concept (MEM—Mesohabitat Evaluation Model). Statistical analysis clearly revealed significant differences (p < 0.001) for the same mesohabitats (e.g. riffles) in different rivers concerning the tested abiotic habitat parameters. A comparative analysis of hydromorphological parameters (width‐depth variance, Froude number) showed no correlation to mesohabitat variability based on 2D/3D numerical modelling related to a range of flows (n = 10) (low flow to annual flood). Only an increasing hydraulic radius (Rhy) was correlated to an increase in fast run and a decrease in run habitats. In a case study, a Fish Guild Concept (FGC) is presented which links mesohabitats to the rheophilic fish guild (12 fish species grouped) at the Sulm River. Mesohabitat suitability (preferred, useable and avoided) for the FGC was determined for spawning, juveniles (0+, 1+), sub‐adult and adult stages based on meso‐unit and point abundance electro‐fishing. Copyright © 2010 John Wiley & Sons, Ltd.This article was published online on March 3, 2010. An error was subsequently identified in Figure 1. This notice is included in the online and print versions to indicate that both have been corrected [March 10, 2010].

Epigean ant communities in Atlantic Forest remnants of São Paulo: a comparative study using the guild concept

Epigean ant communities in Atlantic Forest remnants of Sao Paulo: a comparative study using the guild concept. The guilds constitute a valuable ecological tool, because they allow conducting comparisons among environments under different conditions. The ants can be used as ecological indicators, mainly for the monitoring of degraded forest areas. The aim of this research was to study guild organization among the epigeous Formicidae living in Atlantic forest remnants of the State of Sao Paulo, Brazil. Ant collections were performed in three distinct Atlantic forest biome areas: arboreal littoral vegetation (restinga) (Cananeia), semideciduous seasonal forest (Piracicaba) and dense ombrophylousforest (Pariquera-Acu). After identification, the ants were grouped into guilds, based on the ecological attributes of behavior and habit, according to the literature. Nine guilds were found; the semideciduous seasonal forest ecosystem presented eight of them, followed by the arboreal sandbank (7) and dense ombrophylous forest (6). The guilds found were: litter omnivorous and scavengers, granivorous species, specialist predators living in litter and soil, litter generalist predators, subterranean mealybug-dependent species, army ants, dominant or subdominants arboreal, that occasionally forage on the ground, soil or litter dominant and fungus-growers, using feces and insect body fragments. The guilds found can be used in the monitoring of the mirmecofauna in the Atlantic Forest biome, supplying insights for further ecological studies.

Guilds or functional groups: does it matter?

Although most researchers use the terms “guild” and “functional group” more or less synonymously, these two concepts bear different meanings. The guild concept refers primarily to the mechanisms of resource sharing by species in a competitive context whereas the functional groups concept is concerned with how a resource or any other ecological component is processed by different species to provide a specific ecosystem service or function. In many cases but not necessarily all, the two concepts are the two “faces” or “sides” of the same coin: the sharing by species of a similar resource is the guild facet (structural), while the ecosystem processes these species eventually perform through resource exploitation is the functional group facet. The two concepts differ in that competitive relationships within groups of species are not the focus of the functional group approach, exactly as processes or functions are not the focus of the guild approach. A group of species can be considered either as a guild or a functional group depending on the question addressed. Guild and functional group membership is independent of phylogenetic relationships but because species tend to share similar life history traits and adaptations through common evolutionary history, guild and functional group associates are often closely related. The concept of guild has had broader application in animal studies than in plant studies, whereas the reverse is true for the concept of functional group. Recent methodological advances to objectively partition species into guilds and functional groups, taking into consideration the most relevant characters or traits for delineating them, provide the means to construct an operational framework for making in situ and ex situ experiments that are urgently needed for a better understanding of the role of species in ecosystem functioning, especially in relation to global change concerns.

Dietary guild structure of the fish community in the Northeast United States continental shelf ecosystem

Trophic guild analysis identifies groups of species that use similar resources within a community. We evaluated the trophic guild structure in an assemblage of 40 fish species in the North- east United States shelf ecosystem using a 25 yr database of food habits. We explicitly accounted for ontogenetic diet shifts by separating predator species into size classes. There were 14 significant trophic guilds. These distinguished predators based upon prey size and location in the water column (i.e., benthic to pelagic feeding). Ontogenetic diet shifts were important in guild structure, particu- larly within dominant piscivores. The mean dietary overlap both between and within guilds was notably lower than in other fish communities due to the broad spatial and temporal scale of the study, the diversity of prey types consumed, and the generalist nature of predators in this system. The guild concept is a useful framework to simplify highly connected, complex ecosystems like the Northeast US continental shelf and identify ecologically similar functional units.

Strengths abd weaknesses of the reef guild concepts and quantitative data: Application to the upper Capitan-massive community (Permian), Guadalupe Mountains, New Mexico-Texas

Analyses of large acatate sheet tracings, close-up photos and 105 sub-horizontal quadrat surfaces at four localities near the base of the Guadalupe Mountains Escarpment indicate that the biotic framework of the upper Capitan reef was built by about 35 species: one codiacean (Eugonophyllum sp.), 17 calcisponges, 9 bryozoans, one richthofenid brachipod, some crinoid (known only from columns), 4 Problematica and microbes. This widespread fossil community included members of the Constructor, Baffler and Binder Guilds. A re-evaluation of the Guild Concept (Fagerstrom, 1987, 1991) highlights the validity of the functional roles of the Constructor and Binder Guilds for reef construction. Members of the Baffler Guild, however, need to be revised and an interpretation of microbial micrite and cryptic biota remains controversial. Open surface phylloid algal and cryptic sponge-bryozoan dominated sub-communities were of only local importance. The upper Capitanmassive differs from its Permian conterparts in the low diversity and areal cover of the frame-building biota, low micrite content and abundant micro-frameworks, i.e, intergrown small sponges, Problematica and syndepositional cements (botryoidal and isopachous, fibrous calcite). Quantitative areal cover data were assessed at various scales. Large acetate sheets generally have low coverage of macro-biota (5.4%). By contrast, analysis of small areas of local high areal cover (selected acetate sheet quadrats, subvertical photographs, and quadrat samples: 15–21%) provide detailed insights into clustered patches forming the inital reef framework. Both data sets provide useful clues for an integrated approach to framework assessment. Mean acetate sheet data are limited by their somewhat generalized pattern, while small investigation areas may overemphasize local variation. Erect and pendant sponges with solitary, sub-cylindrical and multi-branche/clonal forms, were the predominant initial frame-builders in both open surface and cryptic habitats. Selective larval recruitment of erects sponges to firm substrates produced continous upward accretion of the initial framework. On open surfaces and in pores formed by tabular sponges and fenestrate bryozoans, erect and pendant sponges were supported in their hydrodynamically unstable growth position by encrusters, chieflyArchaeolithoporelle hidensis, Shamovella obscura, an unnamed tubular organism, and microbes. Subsequent growth ofArchaeolithoporella hidensis, microbial crusts and syndepositional cements on the outer walls of live sponges would have impeded ambient water circulation and may have led to ‘creeping sponge death by suffocation’ or complete encrustation after death. Filling of pores in the initial and encrusted reef framework by internal sediment (packstone-grainstone; derived from the framework and the back-reef shelf/platform) and voluminous syndepositional marine-phreatic cements completed the framebuilding process.

Foraging Strategies of Stemborer Parasites and their Application to Biological Control

Patterns of stemborer life history and the foraging patterns exhibited by a taxonomically diverse array of stemborer parasites are described. Foraging strategies provide functional descriptions of natural parasite groupings and include elements of the guild concept plus ecological, behavioural, and morphological adaptations that enable a parasite to locate and exploit a particular host effectively. Elements of the foraging strategy include: host stage attacked, microhabitat of the host, cues employed to locate and identify the host, and method of host attack. Possible constraints presented by the crop plants to the success of different foraging strategies exhibited by groups of parasites are explored.

Resource use within the crab-eating guild of the upper Kairezi River, Zimbabwe

ABSTRACTCape clawless otters Aonyx capensis and African mottled eels Anguilla bengalensis were suspected of reducing numbers of rainbow trout Oncorhynchus mykiss in the upper Kairezi River, Zimbabwe, by preying on them and competing for the river crab Potamon perlatus. The analysis of otter, eel and trout diets showed that this is unlikely. Trout was an unimportant prey item for otters, none were found in the stomachs of 13 large eels, and any predation was probably minimised by the low densities of these predators. Some competition was probably present because crabs occurred in the diets of otters (relative occurrence 41.9%), eels (63.2%) and trout (7.4%), but it was impossible to quantify. Since these predators shared the crab food resource, the guild concept provided the basis for an analysis of their potential competitive relationships. Comparisons between the sizes of crabs selected and those available suggested that resource partitioning was occurring. Trout selected small crabs from the invertebrate drift, and because they were restricted by their mouth gapes. Otters and large eels ate larger, more abundant crab sizes; it is proposed that they instead partition resources spatially by feeding in separate micro-habitats. Intraguild predation by otters on eels may benefit trout by reducing competition for aquatic insects. Competition within the guild probably recedes in the dry season, when eels become inactive.

On the use of the guild concept in plant ecology

The original definition of the guild is reiterated and the concept discussed and placed in the context of related concepts such as resources and competition. From this conceptual framework the current use of guilds in studies of plant community ecology is evaluated. We discuss the criteria with which species are assigned to guilds, the association of guilds with specific communities, the resource classes on which guilds are based, and the competitive relationships between species of a guild. We conclude that the guild is presently applied in a much more loose way as compared to its original definition. In particular, the a priori assignment of species to guilds on the basis of the use of well-defined resource classes is often relaxed. This obscures the insight that the guild structure may provide in the role of resource partitioning and competition in structuring the community. A more strict use of the concept is advocated.

Importance of the Guild Concept to Fisheries Research and Management

The concept of the guild has appealed to fisheries researchers and managers for simplifying analysis and assisting in the prediction of community change. Guilds have been developed based on reproduction, feeding, habitat use, and morphology. In most published accounts, guilds were used to describe a community change in response to some environmental perturbation (e.g., stream habitat modification or siltation). Members of a guild are often expected to react similarly to environmental change. However, little evidence exists to support the extrapolation of population changes in one guild member to that of other members of the same guild. It may be more reasonable to assume that the combined abundance of all species in a guild can more accurately reflect changes in their primary resource or a limiting factor. Thus, we suggest that guilds reflect the characteristics of a super-species—a unit that responds to environmental change in a more predictable manner than individual species. We recommend that guilds be developed based on critical environmental variables that are most influential in determining community composition. Also, the use of guild definitions needs to be evaluated with long-term data sets to ascertain their true ability to describe community dynamics.

The Guild Concept and the Structure of Ecological Communities

A guild is defined as a group of species that exploit the same class of environmental resources in a similar way. This term groups together species without regard to taxonomic position, that overlap significantly in their niche requirements. The guild has a position comparable in the classification of exploitation patterns to the genus in phylogenetic schemes. . . To be considered a member of the foliage-gleaning guild in the oak woodland, the major portion of a bird species' diet had to consist of arthropods obtained from the foliage zone of oaks. As a result, birds that occasionally use the foliage zone were excluded even though they may have exerted some influence on the guild's food supply. (130, p. 335)

Reef-building guilds and a checklist for determining guild membership

The need for rapid descriptive and interpretive surveys of diverse and structurally complex communities has led to several field techniques for use by taxonomic non-specialists. A new approach to such surveys is the application of Root's guild concept to reef communities. In addition to its taxonomic simplicity, other advantages of the reef guild concept include its applicability to a great variety of reef community types: e.g. both living and fossil, shallow and deep water, diverse and depauperate. Additionally, the impacts of geologic mass extinction events on reef communities may be more readily interpreted by changes in guild structure. Assignment of individuals, colonies and taxa to one of the three reef-building guilds (i.e. Constructor, Baffler, Binder) is based on three fundamental skeletal properties: (a) dominant growth direction in relation to the substrate, (b) functional morphology and (c) skeletal size and strength/rigidity. These properties, combined with aspects of the occurrence and distribution of the skeletons, are used to create a hierarchical checklist for guild assignment consisting of six criteria (which range from 1 as most important to 6 as least important): (1) habit; growth habit, (2) life-form; growth form, (3) skeletonization; skeletal strength/rigidity, (4) skeletal volume; coloniality, (5) biostratonomy; taphonomy and (6) skeletal packing density. To demonstrate the method of determining guild membership, these criteria are used for analysis of the algae and sponges in teh Upper Capitan Limestone (Late Permian), Guadalupe Mountains, New Mexico. Such analysis indicates that the guild structure of this reef community is quite similar to those in other algal-sponge Late Carboniferous-Middle Triassic reefs and very dissimilar to those in Oligocene-Holocene reefs.