Article

The effect of ants on soil properties and processes (Hymenoptera: Formicidae)

September 2008
Myrmecological News 11(11):191-199

Authors:

Jan Frouz

Charles University in Prague

V. Jílková

Biology Centre CAS

Ants are ecosystem engineers, greatly affecting physical, chemical, and biological properties of the soil. The effects on physical soil properties are connected with the building of corridors and galleries, which increase soil porosity and may cause separation of soil particles according to their size. Ant-mediated chemical changes of soil are represented mainly by a shift of pH towards neutral and an increase in nutrient content (mostly nitrogen and phosphorus) in ant nest-affected soil. These effects correspond with accumulation of food in the nests and the effect on biological processes, such as ac-celeration of decomposition rate. Effects on biological soil properties may be connected with increased or decreased microbial activity, which is affected by accumulation of organic matter and internal nest temperature and especially moisture. Effects on the soil vary between ant species; substantial variation can be found in the same species living in different conditions.

The impacts of tropical mound-building social insects on soil properties vary between taxa and with anthropogenic habitat change

Article

Nov 2022
APPL SOIL ECOL

Ants and termites reach high abundances in the tropics and substantially affect the environment through a range of their activities. Because of foraging and decomposition of organic matter at their nesting sites, these locations show fundamentally altered soil properties compared to the adjacent soil. However, such changes are typically studied only within one species or taxon and in one habitat type. Consequently, it is not clear how these effects vary across different taxa and in relation to anthropogenic habitat change. In this study we assess the impacts of different mound-building taxa across a gradient of tropical habitat change in SE Asia comprising primary forest, logged forest and oil palm plantation. To do this we analysed chemical soil properties of mounds of multiple taxa of social insects, with some taxa spanning the full habitat change gradient, and where taxa differ in their mound construction type. Our results show that soils in mounds and adjacent soils have consistently different properties. However, these patterns differ both between social insect taxa and across habitat types. Specifically, mounds of soil-feeding termites Dicuspiditermes spp. were substantially enriched in basic soil nutrients such as C, N, P, especially in oil palm, while mounds of the leaf litter-feeding termite Macrotermes gilvus were depleted. Ant mounds did not show a clear pattern. This indicates that different social insect taxa in a particular habitat affect soil properties in differing ways, and furthermore that such impacts can change when a habitat is anthropogenically altered. Our research highlights the importance of termites for driving the heterogeneity of soil properties and nutrient redistribution across tropical landscapes.

Influence of ant–grass association on soil microbial activity through organic matter decomposition dynamics in Lamto savannah (Côte d’Ivoire)

Article

Aug 2021

Ants are widely regarded as ecosystem engineers because of their effect on soil structure and on the flow of energy. However, little is known about their influence on the carbon flux in tropical humid savannah. Recent investigations in a humid savannah ecosystem in Lamto showed that ant nests’ association with perennial grasses enhances their growth and productivity. This study aimed at understanding the influence of ant nests on soil micro‐organism's activity beneath grass tufts. The kinetic of mineralisation was tested in laboratory conditions at various times (days 1, 2, 4 and 7) beneath three grass species associated and not associated with ant nests, following the CO2 amount released at 30℃ during soil respiration. The amount of CO2 released from the soil is higher beneath grass tufts associated with ant nests compared with those not associated with ant nest. The highest amount of CO2 released from the soil was found beneath Hyparrhenia diplandra tufts followed by Andropogon schirensis tufts and the lowest under Loudetia simplex tufts. This study has shown that ant nests’ association with grass tufts enhances microbial activity in this savannah ecosystem. Les fourmis sont largement considérées comme des ingénieurs de l'écosystème en raison de leur effet sur la structure du sol et sur le flux d'énergie. Cependant, on sait peu de choses sur leur influence sur le flux de carbone dans les savanes tropicales humides. Des études récentes dans un écosystème de savane humide à Lamto ont montré que l'association des nids de fourmis avec des herbes pérennes améliore leur croissance et leur productivité. Cette étude visait à comprendre l'influence des nids de fourmis sur l'activité des microorganismes du sol sous les touffes d'herbe. La cinétique de minéralisation a été testée en laboratoire à différents moments (jour 1, 2, 4 et 7) sous trois espèces de graminées associées et non associées à des nids de fourmis, en suivant la quantité de CO2 libérée à 30°C pendant la respiration du sol. La quantité de CO2 libérée du sol est plus élevée sous les touffes d'herbes associées aux nids de fourmis que sous celles qui ne le sont pas. La plus grande quantité de CO2 libérée du sol a été trouvée sous les touffes d'Hyparrhenia diplandra, suivie par les touffes d'Andropogon schirensis et la plus faible sous les touffes de Loudetia simplex. Cette étude a montré que l'association des nids de fourmis avec les touffes d'herbe améliore l'activité microbienne dans cet écosystème de savane.

The bacterial and fungal community composition in time and space in the nest mounds of the ant Formica exsecta (Hymenoptera: Formicidae)

Article

Full-text available

Aug 2021

We have previously shown that the fungal and bacterial communities in nests of ants Formica exsecta are distinct from those in the surrounding soil. Now, the results from our three-year study show that the nests also provide a temporally stable environment, where microbial taxa, less tolerant of climatic fluctuations, could survive through unfavorable seasons. The nest could thus act as a reservoir for such microbial inocula, promoting the divergence of the nest communities over time. Abstract In a subarctic climate, the seasonal shifts in temperature, precipitation, and plant cover drive the temporal changes in the microbial communities in the topsoil, forcing soil microbes to adapt or decline. Many organisms, such as mound-building ants, survive the cold winter owing to the favorable microclimate in their nest mounds. We have previously shown that the microbial communities in the nest of the ant Formica exsecta are significantly different from those in the surrounding bulk soil. In the current study, we identified taxa, which were consistently present in the nests over a study period of three years. Some taxa were also significantly enriched in the nest samples compared with spatially corresponding reference soils. We show that the bacterial communities in ant nests are temporally stable across years, whereas the fungal communities show greater variation. It seems that the activities of the ants contribute to unique biochemical processes in the secluded nest environment, and create opportunities for symbiotic interactions between the ants and the microbes. Over time, the microbial communities may come to diverge, due to drift and selection, especially given the long lifespan (up to 30 years) of the ant colonies.

Chance or Necessity - The Fungi Co−Occurring with Formica polyctena Ants

Article

Full-text available

Feb 2021

Studies on carton nesting ants and domatia−dwelling ants have shown that ant–fungi interactions may be much more common and widespread than previously thought. Until now, studies focused predominantly on parasitic and mutualistic fungi–ant interactions occurring mostly in the tropics, neglecting less−obvious interactions involving the fungi common in ants’ surroundings in temperate climates. In our study, we characterized the mycobiota of the surroundings of Formica polyctena ants by identifying nearly 600 fungal colonies that were isolated externally from the bodies of F. polyctena workers. The ants were collected from mounds found in northern and central Poland. Isolated fungi were assigned to 20 genera via molecular identification (ITS rDNA barcoding). Among these, Penicillium strains were the most frequent, belonging to eight different taxonomic sections. Other common and widespread members of Eurotiales, such as Aspergillus spp., were isolated very rarely. In our study, we managed to characterize the genera of fungi commonly present on F. polyctena workers. Our results suggest that Penicillium, Trichoderma, Mucor, Schwanniomyces and Entomortierella are commonly present in F. polyctena surroundings. Additionally, the high diversity and high frequency of Penicillium colonies isolated from ants in this study suggest that representatives of this genus may be adapted to survive in ant nests environment better than the other fungal groups, or that they are preferentially sustained by the insects in nests.

The abundance, biomass, and distribution of ants on Earth

Article

Sep 2022
P NATL ACAD SCI USA

Knowledge on the distribution and abundance of organisms is fundamental to understanding their roles within ecosystems and their ecological importance for other taxa. Such knowledge is currently lacking for insects, which have long been regarded as the “little things that run the world”. Even for ubiquitous insects, such as ants, which are of tremendous ecological significance, there is currently neither a reliable estimate of their total number on Earth nor of their abundance in particular biomes or habitats. We compile data on ground-dwelling and arboreal ants to obtain an empirical estimate of global ant abundance. Our analysis is based on 489 studies, spanning all continents, major biomes, and habitats. We conservatively estimate total abundance of ground-dwelling ants at over 3 × 10 ¹⁵ and estimate the number of all ants on Earth to be almost 20 × 10 ¹⁵ individuals. The latter corresponds to a biomass of ∼12 megatons of dry carbon. This exceeds the combined biomass of wild birds and mammals and is equivalent to ∼20% of human biomass. Abundances of ground-dwelling ants are strongly concentrated in tropical and subtropical regions but vary substantially across habitats. The density of leaf-litter ants is highest in forests, while the numbers of actively ground-foraging ants are highest in arid regions. This study highlights the central role ants play in terrestrial ecosystems but also major ecological and geographic gaps in our current knowledge. Our results provide a crucial baseline for exploring environmental drivers of ant-abundance patterns and for tracking the responses of insects to environmental change.

REVIEW ON ECOLOGICALASPECTS OF ANTS WITH SPECIAL REFERENCE TO AGRICULTURAL HABITATS

Article

May 2022

Agricultural systems are areas of land where humans manipulate physical, chemical, and biological processes using a cluster of practices to obtain a benecial product for their use. To understand the level of organization in a particular region we must consider biotic and abiotic factors and the interaction between them to employ best conservation practices to restore biodiversity in this region. Ants perform a different role in agro ecosystems like pollination, soil turbation, bio indication and the regulation of crop-damaging insects. Agro ecology management of ants in tree cropping systems required some information about positive and negative impacts on crops and pest species. This review article provides an overview of knowledge of the roles performed by ants in agricultural habitats.

Dissipation of seabird-derived nutrients in a terrestrial insular trophic web

Article

May 2022
AUSTRAL ECOL

Highly mobile organisms can transport nutrients and energy among distinct ecosystems, such as between oceanic foraging areas and terrestrial breeding sites. Seabirds are great nutrient carriers and potentially play a key role in the maintenance of trophic webs on islands. In this study, we assessed three dimensions of marine nutrient dissipation—horizontal, temporal and vertical—on the tropical Meio Island of Fernando de Nor- onha Archipelago, Brazil. For this, C3 and C4 plants, ants and spiders found in a 100 m long transect between colonies of masked (Sula dactylatra) and red-footed boobies (Sula sula) were sampled during the rainy (the masked booby breeding period) and dry seasons (the red-footed booby breeding period). The marine contribu- tion to the terrestrial trophic web was analysed using Bayesian mixing models from a carbon and nitrogen stable isotope data set. The main findings indicate that marine nutrients in the terrestrial trophic web dissipated hori- zontally as the distance from the colony increased, which was more marked during the rainy season. On the ver- tical axis, the relative contribution of marine nutrients in terrestrial consumers was strongly related to food habits but not necessarily to the trophic level, dissipating rather than increasing, due to variable omnivory and the use of terrestrial food sources. The breeding strategy of the masked booby (i.e. incubating eggs on the ground), in addition to a larger body size and larger colony, could produce a more concentrated pulse of nutri- ents in comparison to seabirds nesting sparsely on trees, contributing more efficiently to the enrichment of mar- ine nutrients on land. The importance of seabirds for the maintenance of interconnected ecosystems has been demonstrated, and the role of marine-derived nutrients in the enrichment of nutrient-poor tropical islands.

ΚΟΚΚΙΝΑ ΔΑΣΙΚΑ ΜΥΡΜΗΓΚΙΑ

Book

Full-text available

Sep 2021

Anthills: stressor or opportunity for plant assemblage diversity? Evidence from Mediterranean Dasypyretum grasslands

Article

Jul 2021
ETHOL ECOL EVOL

We explored the structure of plant assemblages that settles around the anthills of a guild of Hymenoptera Formicidae (Messor wasmanni Krausse 1910, Tapinoma nigerrimum Nylander 1856 and Aphaenogaster spinosa Emery 1878), observable in urban grasslands dominated by Dasypyrum villosum (Rome, Central Italy). Since it is known that ants act as a disturbing factor on plant assemblages of grasslands, our hypothesis was that vegetation structures suffer from some stressors that affect, in this plant association, the dominant plant structure. We compared the plant assemblages observed in the plots of the anthills with the control grassland assemblages using a diversity/dominance diagram. We recorded 63 plant taxa. The average number of plant species was found to be significantly lower in anthill plots than in control grassland plots. In anthill plots, dominant plant species (Polygonum romanum, Poa trivialis Vulpia myuros, Aira elegantissima and Vulpia ligustica) have been found to be different from control grassland plots (Convolvolus arvensis, Dasypyrum villosum, Poa trivialis and Sheradia arvensis). Anthill plant assemblages were found to be significantly different (One-way PERMANOVA) and poorer in terms of species richness, less diversified, and with a reduced species turnover than control grassland plots. Whittaker plot analysis seems to show that the plant assemblages of the control, with greater evenness, emphasize a stressed condition in anthill plant assemblages. Non-metric multidimensional scaling shows a set of species strictly linked to anthills. Our data seem to confirm the role of ants as a stressor in the plant assemblage structures of Mediterranean urban grasslands. However, our results also show that the peculiar ant nest conditions may favor plant species less represented in the Dasypyretum grasslands (i.e. Polygonum romanum) or even absent in this plant assemblage (i.e. Aira elegantissima, Cynodon dactylon and Poa annua), thus increasing the overall local plant diversity.

Impact d'une espèce ingénieure de l'écosystème et son utilisation en restauration écologique - Le cas de Messor barbarus (L.) dans les pelouses méditerranéennes

Thesis

Full-text available

Dec 2020

Tania De Almeida

L’objectif principal de cette thèse était double : (i) mesurer l’impact d’une espèce de fourmi sur son écosystème, afin (ii) d’en déduire des applications potentielles dans le domaine de la restauration écologique. Les fourmis sont parmi les organismes les plus abondants des écosystèmes terrestres et occupent des zones géographiques très variées. Elles jouent des rôles écologiques clés dans de nombreux écosystèmes comme ingénieurs du sol, prédateurs ou régulateurs de la croissance et de la reproduction des plantes. Cependant les données collectées localement sont souvent parcellaires et ne permettent pas d’avoir une vision complète de l’impact d’une espèce sur son milieu. Messor barbarus (L.), connue pour redistribuer les graines et pour modifier les propriétés physico-chimiques du sol, est largement répandue dans le Sud-Ouest de l’Europe notamment au sein des pelouses méditerranéennes. Elle pourrait donc jouer un rôle majeur dans la composition et structuration de ces pelouses caractérisées par une forte biodiversité mais dont le nombre et la superficie ont drastiquement diminué ces dernières décennies. Dans un premier temps, par une étude multi-compartiments, nous avons confirmé l’hypothèse selon laquelle M. barbarus est une ingénieure de l’écosystème au sein des pelouses méditerranéennes. Elle transforme cet habitat en modifiant, comme attendu, les propriétés physico-chimiques du sol. Ces modifications sont associées à une augmentation de la biomasse et de l’hétérogénéité des communautés végétales ainsi qu’à des changements dans les faunes épigée et endogée (abondance, occurrence et structure des communautés). De plus, M. barbarus modifie profondément les relations trophiques et non trophiques interspécifiques et entre les espèces et leur habitat. L’hétérogénéité créée à l’échelle locale par l’activité de cette fourmi, entraine une diversification des niches écologiques au sein de ces pelouses. Malgré leur rôle souvent majeur sur le fonctionnement des écosystèmes, les fourmis ne sont que très rarement considérées en restauration écologique. Sur notre site d’étude, un chantier de réhabilitation d’une pelouse sèche après une fuite d’hydrocarbures et un transfert de sol, M. barbarus a permis d’accélérer la restauration des propriétés physico-chimiques du sol mais aussi de la banque de graines à moyen terme - sept ans après la réhabilitation du site. Ces résultats font donc de cette espèce une bonne candidate en ingénierie écologique. Afin de généraliser l’utilisation des fourmis en restauration écologique, nous proposons une méthodologie à destination des gestionnaires basée sur l’utilisation de traits fonctionnels et d’histoire de vie. Pour cela nous avons évalué le potentiel des fourmis en écologie de la restauration, puis nous avons listé l’ensemble des traits connus pour affecter les compartiments abiotiques et biotiques et/ou pertinent pour effectuer un suivi du succès de la phase de restauration. La méthodologie proposée permet une première sélection des espèces potentiellement utilisables en fonction des objectifs de restauration.

Barbed wire fringe vegetations in central Flanders: plant species diversity, community composition, environmental drivers, and management.

Thesis

Full-text available

Jan 2023

Robbe Cool

Semi-natural grasslands are among the most endangered vegetation types in Europe, threatened by inadequate management, habitat fragmentation and excessive nitrogen deposition. As a consequence, many of them have received a protection status as nature reserves. Yet this protection applies almost exclusively to large contiguous areas whereas small grasslands often do not receive the right protection status they deserve. This is especially the case for the many historical unimproved grasslands which have now been reduced to road verges and unimproved grassland margins and which often still contain relict populations of valuable plant species. Given their small size and increased isolation, such populations have become relict populations with expected extinctions as a result. However, these grassland relicts are important for preserving high species diversity and ecosystem dynamics at the landscape-scale, for instance as corridors and stepping stones or as microhabitats. Vegetations at the fringes of the pastures, mainly under the barbed wire (“prikkeldraadvegetaties”), are a specific example of such grassland relicts. As a result of agricultural intensification, wooded edges were replaced by barbed wire as enclosures. Although intensified grazing threatened the unique grassland vegetation through trampling and defaecation, cattle acted as the desired nature managers along the fringes. By grazing and trampling the border of the fringes, they create a high-quality microhabitat under the barbed wire. Moreover, the microrelief, consisting of mounds and lynchets, allows the small-scale biodiversity under the wire to increase. Even though the concept of barbed wire vegetation is well established in botanical societies, little is known about these vegetations in terms of their species richness and the drivers of their plant species composition. Nevertheless, they have been shown to harbour higher plant richness than adjacent pastures, which could make them a species resource pool for future conservation projects. In this study, we want to investigate barbed wire fringe vegetations by conducting a descriptive analysis (RQ1 + RQ2) and determining the environmental conditions for high-quality barbed wire vegetations (RQ3 + RQ4), followed by establishing guidelines for conservation and management of the fringes (RQ5). In June 2021, we inventoried 40 fringe vegetations in the Hageland-Zuiderkempen region (Belgium). We mapped the vegetation cover of plants in a 1 m * 2 m plot. We identified the environmental parameters: ‘presence of mounds’, ‘presence of lynchet’, ‘presence of an adjacent historical permanent grassland’, ‘grazing regime’ and ‘adjacent land use’. In addition, we collected soil samples to analyse pH, organic matter, moisture, and Olsen-phosphorus. We calculated land use intensity (LUI) of the fringe combining the LUI of the immediate surroundings, the vegetation of the pasture and the grazing regime. Our dataset was supplemented with Ellenberg-values for light, nitrogen, and mowing-tolerance as well as the functional group and conservation status of each species (habitat specialists). (RQ1 + RQ2) To describe the ecology of fringes, we divided sites into groups based on the distinctive and indicator species of each fringe. We determined the associated plant community and alliance of each group and tested in which of the abovementioned environmental parameters they differed. Using multivariate analysis of variance, we determined which variables explained the variation in the vegetation dataset. (RQ3) To evaluate which environmental variables had a significant correlation with the habitat specialist richness and Shannon index, we performed a full linear regression on the environmental variables followed by model selection using the Akaike information criterion (AIC) to find the most parsimonious model. To determine whether the biodiversity indices were highest at an intermediate land use, we built a quadratic model using total LUI and its quadratic term as explanatory variables. (RQ4) To uncover the specific mechanisms by which fringe dynamics improve the habitat quality, we determined (1) the nitrogen/phosphorus levels at an intermediate LUI, (2) differences in Olsen-phosphorus and soil moisture due to the presence of a lynchet, (3) the effect of grazing on Olsen-phosphorus and habitat specialist richness and (4) the influence of LUI on the cover of functional groups. Fringe plant species benefit from the specific conditions under the barbed wire promoted by intermediate grazing. They can escape from the negative effects of trampling and defaecation. These plants can be classified into two groups dependent on the history (relict-species) and abiotic conditions (grazing-avoiding species) of the vegetation. In our study, we first investigated which plant communities the groups belonged to. We found four different plant alliances (M1 – 4), three of which could be classified as the Molinio – Arrhenatherata community, while fringes of group M2 belonged to the Koelerio – Corynepherata community. Group M2 was considered as the vegetation group with the highest quality, having the highest habitat specialist species richness, nitrogen-poorest conditions and intermediate LUI. The fringes of M2 were located on sandy soils, typical of the Koelerio – Corynepherata community, explaining lower nitrogen levels and pH values. Overall, variation in the vegetation could be explained by all the environmental characteristics except the presence of an adjacent historical permanent grassland. Soil pH was the most significant explanatory variable, but we attribute the differences in soil type to geographical location. We were able to establish that a fringe with an intermediate LUI of 4 (on a scale of 0 to 6), dry soil and the presence of a lynchet was optimal. At an intermediate LUI, plant species richness was highest and most nitrogen-avoiding species were present. An intermediate LUI is the perfect balance between vegetation encroachment and overgrazing. The presence of a lynchet could cause a run-off of phosphorus, although Olsen-P-levels were still too high for all fringes except one. High phosphorus levels may lead to future habitat degradation and extinction of vulnerable species, although some species may still persist for an unexpectedly long time. Soil pH was significantly negatively correlated with species richness and Shannon diversity, but again, geographical location was likely a confounding factor. Furthermore, we expected that the soil maturity and the presence of ant mounds of Lasius flavus were important as well, although we could not demonstrate their effect. High-quality barbed wire fringes can harbor a rich biodiversity of remarkable plants. A total 37 habitat specialist were found in our study, but 24 of which have disappeared over the past 30 years. The main reason for their decline is believed to be the negative effects of small populations and excessive nitrogen and phosphorus deposition. Barbed wire fringe vegetations can substantially contribute to the landscape-scale biodiversity by both increasing the available habitat and their connection between habitats, and as ex-situ back-up of remnant rare plant populations. Although neglected in most conservation projects, these vegetations are easy and inexpensive to conserve. Only an enclosure, which encloses the livestock and allows their grazing underneath, is required. Possible management goals are 1) grassland restoration of the adjacent barbed wire fringe vegetation to allow grassland relict species of the fringe to expand their territory and 2) preservation of their seeds for future reintroductions. However, seed preservation is only possible if the plant populations are still viable. An increase of fringes is not only beneficial for the biodiversity. Indeed, fringes produce healthier food for the livestock, resulting in higher quality of dairy products and meat. This, in turn, leads to healthier consumers. Conserving and establishing new barbed wire fringe vegetations can therefore be important both for the welfare of animals and their consumers, and for biodiversity in the agricultural landscape.

Mulching in lowland hay meadows drives an adaptive convergence of above- and below-ground traits reducing plasticity and improving biomass: A possible tool for enhancing phytoremediation

Article

Full-text available

Nov 2022

We aimed to understand the effect of mulching (i.e., cutting and leaving the crushed biomass to decompose in situ) on above- and below-ground plant functional traits and whether this practice may be a potential tool for enhancing the phytoremediation of lowland hay meadows. To this aim, we evaluated at the community level seven years of mulching application in a PCBs and HMs soil-polluted Site of National Interest (SIN Brescia-Caffaro) through the analysis of the floristic composition and the above- and below-ground plant traits. We found that the abandonment of agricultural activities led to a marked increase in the soil organic carbon and pH, and the over-imposed mulching additionally induced a slight increase in soil nutrients. Mulching favored the establishment of a productive plant community characterized by a more conservative-resource strategy, a higher biomass development, and lower plasticity through an adaptative convergence between above- and below-ground organs. In particular, the analysis of the root depth distribution highlighted the key role of roots living in the upper soil layer (10 cm). Mulching did not show a significant effect on plant species known to be effective in terms of PCB phytoremediation. However, the mulching application appears to be a promising tool for enhancing the root web that functions as the backbone for the proliferation of microbes devoted to organic contaminants’ degradation and selects a two-fold number of plant species known to be metal-tolerant. However, besides these potential positive effects of the mulching application, favoring species with a higher biomass development, in the long term, may lead to a biodiversity reduction and thus to potential consequences also on the diversity of native species important for the phytoremediation.

Stigmergy Mechanism as a Form of Architectural Space Programming

Article

Full-text available

Aug 2022

This paper explores the understanding of architectural spaces driven by the knowledge that animals communicate by modifying the environment, in which they live. The way that animals communicate by modifying the environment forms an interaction, which is referred to as stigmergy, a mediated form of animal interaction. The paper elaborates on the process of stigmergy, in which animal colonies communicate with their living environment and leave different kinds of spatial traces. The paper argues that the stigmergy process can be potentially used as the basis of architectural programming. This writing explores multiple scenarios of the process of stigmergy in several insect colonies, highlighting the mechanism of stigmergy that is driven by three main components of stigmergy, namely Agent, Medium, and Traces. The writing focuses on how in stigmergy the agent interacts within a particular medium and creates traces in spaces. Findings on such mechanism of interaction are utilized to inform architectural programming that is based on the interaction between humans, animals, and the environment as integrated ecological systems. The development of the programming using the stigmergy method appropriates the social mechanisms of insects, in composing the spatial development of architecture, producing architectural systems for soil fertilization and revitalization of the environment.

Local and landscape environmental heterogeneity drive ant community structure in temperate semi-natural upland grasslands

Preprint

Jul 2022

Environmental heterogeneity is an important driver of ecological communities. Here, we assessed the effects of local and landscape spatial environmental heterogeneity on ant community structure in temperate semi-natural upland grasslands of Central Germany. We surveyed 33 grassland sites representing a gradient in elevation and landscape composition. Local environmental heterogeneity was measured in terms of variability of temperature and moisture within and between grasslands sites. Grassland management type (pasture vs. meadows) was additionally included as a local environmental heterogeneity measure. The complexity of habitat types in the surroundings of grassland sites were used as a measure of landscape environmental heterogeneity. As descriptors of ant community structure, we considered species composition, community evenness, and functional response traits. We found that extensively grazed pastures and within-site heterogeneity in soil moisture at local scale, and a high diversity of land cover types at the landscape scale affected ant species composition by promoting nest densities. Ant community evenness was high in wetter grasslands with low within-site variability in soil moisture and surrounded by a less diverse landscape. Fourth-corner models revealed that ant community structure response to environmental heterogeneity was mediated mainly by worker size, colony size, and life history traits related with colony reproduction and foundation. We discuss how within-site local variability in soil moisture and low intensity grazing promote ant species densities, and highlight the role of habitat temperature and humidity affecting on community evenness. We hypothesize that a higher diversity of land cover types in a forest-dominated landscape buffers less favorable environmental conditions for ant species establishment and dispersal between grasslands. We conclude that spatial environmental heterogeneity at local and landscape scale plays an important role as deterministic force in filtering ant species and, along with neutral processes (e.g. stochastic colonization), in shaping ant community structure in temperate semi-natural upland grasslands.

Vascular Epiphytes: Plants That Have Broken Ties with the Ground

Article

Jun 2022

Characteristics of thermal processes in ant nests built under stones (Hymenoptera: Formicidae)

Article

Full-text available

May 2022

Ants prefer to nest under stones. This is due to temperature regimes favorable to the development of ant broods. In this paper, we investigated the influence of stone and ambient parameters on ant nests and created a model of thermal processes in ant nests under stones. The simulation results were compared with temperature measurements. Temperature was measured under 20 stones under different illumination conditions (sun, penumbra and shade) for 3 ant species (Myrmica rubra, Formica cinerea, Lasius niger) in Ukraine from April to August 2021. Stones were categorized as hot, warm and cold. Each stone was checked once a week for the number of workers and brood. Under two stones, tem�perature was measured using loggers. The number of workers under hot stones in spring increased three weeks earlier than under cold and warm ones. In May-June, the maximum number of workers was recorded under hot stones. In July, the number of ants was minimal under all categories of stones. Larvae appeared under hot stones two weeks earlier than under other categories of stones. In August, the number of pupae under cold and warm stones was greater than under hot ones. Number of larvae and pupae was positively influenced by the diameter of the stone, whereas stone height did not exert an important role. Ants preferred to inhabit nests under large flat stones, which are easily heated in spring and warm the soil under them. Another important characteristic was the location of the stones. The highest brood development was noted in nests under stones in open areas well lit by the sun in the daytime. In summer ants migrated from under hot stones, because soil under it dry and warmed. Stones and their position may be important factors in accelerating the development of brood in colonies of ant species that do not have active thermoregulation.

Natural Repellents as a Method of Preventing Ant Damage to Microirrigation Systems

Article

Full-text available

Apr 2022

Ants are important because they damage agricultural equipment, including microirrigation systems. The aim of this research was to assess the efficiency of the incorporation of repellents in drip irrigation tubing as a method of protection against ant damage. Unlike previous studies, we tested a series of nontoxic compounds that are repellent to ants. First, we assessed their repellent effects on a local ant species via olfactometer trials. Then, the candidates showing the best results (cinnamon essential oil, p-anisaldehyde and ethyl anthranilate) were incorporated via compounding, injection and extrusion to polyethylene tubing to test their efficiency in the field. Field tests showed high damage levels in the control tubing containing no repellents, presumably caused by up to six different ant species (Cardiocondyla batesii, Plagiolepis pygmaea, P. schmitzii, Solenopsis sp., Tapinoma nigerrimum and Tetramorium semilaeve). In contrast, the pipes containing the three selected compounds remained almost intact, with the treatment including ethyl anthranilate showing no damage at all. These results suggest the strong repellent potential of the selected compounds, even when integrated into plastic, as well as the apparent success of the proposed methodology against the damage caused by ants. The diversity of damage-causing agents that exist in or above the soil strongly encourages further studies to determine the overall efficiency of repellents in protecting irrigation pipes.

Differentiated impacts of the feeding-habits of three ant species on carbon mineralization in tropical forest soils

Article

May 2022
EUR J SOIL BIOL

Ants affect carbon mineralization probably through their modifications on spatiotemporal heterogeneity in soil nutrients. However, it is still unclear whether the impacts of belowground-nesting ants on carbon mineralization varied with species. For this study, three belowground-nesting ants (i.e., honeydew harvester Pheidole capellini, predatory Odontoponera transversa, and saprophagous Pheidologeton affinis) were considered to identify the effects on soil carbon mineralization in the tropical Xishuangbanna (Yunnan, southern China). P. capellini had the greatest carbon mineralization (1.9 times) in the nest soils compared with control soils, followed by O. transversa (1.5 times) and P. affinis (1.3 times). Ants had different modifications on the changes of carbon mineralization as well as soil nutrient availability. The highest increased levels (24.7–298.5%) of carbon and nitrogen pools were observed in P. capellini nests compared with control soils. Soil carbon and nitrogen pools together affected soil carbon mineralization dynamics. Total organic carbon, microbial biomass carbon, and readily oxidizable carbon were the key factors regulating soil organic carbon mineralization, followed by total, ammonium and dissolved nitrogen. Our results suggested that carbon mineralization differed among ant species, which was tightly linked with the effects of different feeding guilds on nutrient availability in tropical forest soils.

Ant body size mediates functional performance and species interactions in carrion decomposer communities

Article

Full-text available

Mar 2022

Growing concern over rapid species declines and extinctions has led to considerable interest in the role of biodiversity for maintaining ecological processes. However, the loss of particular species has more pronounced effects on ecosystem services than others, highlighting the importance of key functional species traits and their relationships to ecosystem functioning. Human induced disturbances, such as species invasions, land use changes or abiotic changes, appear to disproportionally impact larger species rather than smaller ones. The loss of large‐bodied species in the community diminishes key ecosystem services like seed dispersal, pest control, pollination and decomposition. Here we use carrion, a nutrient‐rich ephemeral resource, to test the hypotheses that ants positively affect decomposition rates and that their role in the necrophilous community – as predator or decomposer – is mediated by body size. We further investigate the relative contribution of maggots vs. ants to biomass decomposition. Our results show that ants contributed positively to the decomposition process. Moreover, decomposition was shaped by an intricate interplay between competition and predation among the guild of decomposer insects. As predicted, larger ants show a double action in increasing decomposition rate and predating on maggots, while small ants are rather inefficient decomposers and did not act as predators on other decomposer species. Our study shows that differentiating key taxonomic groups in function of their body size is key to untangle the diversity and directions of the various roles they play within complex ecological processes.

Ants mediate community composition of root‐associated fungi in an ant‐plant mutualism

Article

Full-text available

Mar 2022

Cross‐kingdom interactions with plants were frequently related to microbial pathogens and herbivores. Yet, mutualistic interactions that involve multiple partners can confer cross‐kingdom functional benefits, which have been understudied. Ant gardens (AGs) are recognized as one of the most sophisticated of all symbioses between ants and flowering plants, forming good models to study cross‐kingdom interactions. The aim of this study was to examine whether ant‐plant interactions can influence the community composition of root‐associated fungi. We assessed whether two AG ant species, Camponotus femoratus and Neoponera goeldii, confer different physico‐chemical properties to their nests, and affect root fungal community composition and fungal functional guilds in the bromeliad Aechmea mertensii. The diversity and community composition of root‐associated fungi depended on ant species identity. The two ants had a contrasting influence on the structure and chemistry of the nest, and on the floristic diversity of the AGs. Multiple drivers may therefore determine the root‐associated fungal communities. As the outcome of the ant‐bromeliad interaction depends on the ant species, and because the plants are also involved in interactions with root‐associated symbionts, this study provided evidence that ecologically relevant symbioses can be mediated by cross‐kingdom interactions. Abstract in French is available with online material. Les interactions inter‐règnes avec les plantes ont été principalement abordé par l’étude d’interactions antagonistes avec des pathogènes et des herbivores. Pourtant, les interactions mutualistes qui impliquent plusieurs partenaires peuvent conférer des avantages inter‐règnes qui ont été jusqu’à présent très peu étudiés. Les jardins de fourmis sont reconnus comme l’un des mutualismes les plus sophistiqués entre des fourmis et des plantes à fleurs, et constituent de bons modèles pour étudier les interactions inter‐règnes. L’objectif de cette étude était d’examiner si les interactions plantes‐fourmis pouvaient influencer la composition de la communauté fongique des racines. Nous avons évalué si les deux espèces de fourmis initiant les jardins de fourmis, Camponotus femoratus et Neoponera goeldii, modifiaient les propriétés physico‐chimiques de leurs nids en carton et affectaient la composition et les groupes fonctionnels des communautés fongiques dans les racinaires de la broméliacée Aechmea mertensii. La structure et la composition chimique du nid en carton et la diversité floristique des jardins de fourmis étaient différentes selon l’espèce de fourmis. La diversité et la composition des communautés fongiques racinaires dépendaient de l’identité de la fourmi alors que la diversité fonctionnelle était inchangée. De multiples facteurs biotiques et abiotiques peuvent donc modifier les communautés fongiques associées aux racines. Comme les bénéfices de l’interaction plantes‐fourmis dépendent de l’espèce de fourmis, et comme les plantes sont également impliquées dans des interactions avec des endophytes racinaires, cette étude met en évidence l’importance des interactions inter‐règnes dans la structuration des communautés fongiques racinaires. The two ant gardens ants Camponotus femoratus and Neoponera goeldii had a contrasting influence on the structure and chemistry of the nest, and on the floristic diversity of the ant‐gardens. The diversity and community composition of root‐associated fungi in the bromeliad Aechmea mertensii depended on ant species identity. This study provided evidence of the importance of cross‐kingdom interactions in structuring root‐associated fungal communities

Ant diversity and composition patterns along the urbanization gradients in an arid city

Article

Full-text available

Oct 2021

The dramatic increased rates of uncontrolled urbanisation in various parts of the World have resulted in loss of native species and overall threats to biodiversity. Over the last few decades Saudi Arabia has witnessed a remarkably rapid population growth and unparalleled levels of urbanisation, leading to threats to biodiversity. In this study we focused on arid city (Riyadh, Saudi Arabia) where ant assemblages cross an urban-rural gradient. Ants were collected by pitfall traps from 15 sites along three different urbanisation gradients at 3-monthly intervals throughout 1 year. Ant abundance, species richness, evenness, and α diversity were consistent across the urbanisation gradient. However, significant differences were observed in ant β diversity and assemblage composition between rural and urban, suburban and urban, but not between rural and suburban sites. Eleven ant species were identified as indicator species (IV values between 50.7% and 80.7%). These ant assemblages were influenced by flora, ground cover, soil variables, and urbanisation characteristics. To conclude, we found a significant effect of urbanisation on the β diversity and composition of ant assemblages.

Feeding habits and multifunctional classification of soil-associated consumers from protists to vertebrates

Article

Full-text available

Jan 2022
BIOL REV

Soil organisms drive major ecosystem functions by mineralising carbon and releasing nutrients during decomposition processes, which supports plant growth, aboveground biodiversity and, ultimately, human nutrition. Soil ecologists often operate with functional groups to infer the effects of individual taxa on ecosystem functions and services. Simultaneous assessment of the functional roles of multiple taxa is possible using food-web reconstructions, but our knowledge of the feeding habits of many taxa is insufficient and often based on limited evidence. Over the last two decades, molecular, biochemical and isotopic tools have improved our understanding of the feeding habits of various soil organisms, yet this knowledge is still to be synthesised into a common functional framework. Here, we provide a comprehensive review of the feeding habits of consumers in soil, including protists, micro-, meso-and macrofauna (invertebrates), and soil-associated vertebrates. We have integrated existing functional group classifications with findings gained with novel methods and compiled an overarching classification across taxa focusing on key universal traits such as food resource preferences, body masses, microhabitat specialisation, protection and hunting mechanisms. Our summary highlights various strands of evidence that many functional groups commonly used in soil ecology and food-web models are feeding on multiple types of food resources. In many cases, omnivory is observed down to the species level of taxonomic resolution, challenging realism of traditional soil food-web models based on distinct resource-based energy channels. Novel methods, such as stable isotope, fatty acid and DNA gut content analyses, have revealed previously hidden facets of tro-phic relationships of soil consumers, such as food assimilation, multichannel feeding across trophic levels, hidden trophic niche differentiation and the importance of alternative food/prey, as well as energy transfers across ecosystem compartments. Wider adoption of such tools and the development of open interoperable platforms that assemble morphological, ecological and trophic data as traits of soil taxa will enable the refinement and expansion of the multifunctional classification of consumers in soil. The compiled multifunctional classification of soil-associated consumers will serve as a reference for ecologists working with biodiversity changes and biodiversity-ecosystem functioning relationships, making soil food-web research more accessible and reproducible.

Diversity and Distribution of Forest Ants (Hymenoptera: Formicidae) in Nepal: Implications for Sustainable Forest Management

Article

Full-text available

Dec 2021

The information available on the diversity of ant species and their distribution and interaction with forest health in Nepal remains limited. As part of a nationwide project on forest health, we conducted inventories to assess the diversity and distribution of forest ants and their role in forest management in Nepal. Ants were collected from 187 plots of 10 m × 10 m size along the north–south belt transects in eastern, central, and western Nepal. We used vegetation beating, sweeping, and hand collection methods in selected forest types. In each transect, we designed six plots in each major forest type (Sal, Schima–Castanopsis, and broadleaf mixed forests) and three plots each in deodar, Alnus, riverine, and Cryptomeria forests. We recorded 70 ant species from 36 genera and six subfamilies. This includes five genera and nine species new for the country, as well as eight tramp species, four of which are major ecological, agricultural, and/or household pests. Our study indicates that forest ant species richness is high in western Nepal and the Siwaliks, and it decreases as elevation increases. The high diversity of ant species in the forests of Nepal needs to be assessed with further exploration using multiple sampling methods covering all seasons and forest types. Ants can be useful indicators for ecosystem management and human impacts on forests. Reports of invasive ants in Nepalese forests indicate the relevance of urgent interventions through sustainable forest management initiatives to prevent future incursions.

Changes in native small mammal populations with removal of invasive ant

Article

Sep 2021

Efforts to remove invasive species may benefit native species, but the effects can be complex and unpredictable. Thus, studies of invasive-species removal provide important information for guiding management and providing insight about variation in post-removal impacts within the community. Using southern pine-grassland ecosystems as a model system, we hypothesized that removal of the long-established red-imported fire ant (Solenopsis invicta, hereafter RIFA) would positively influence altricial Peromyscus species, due to increased survival of young in the nest and thus increased recruitment to the population, but would not impact semi-precocial hispid cotton rats (Sigmodon hispidus), which are mobile more quickly after birth and thus at less risk of depredation by RIFA. We compared small mammal populations on sites treated with a granular insecticide (Extinguish Plus) to remove RIFA in southwestern Georgia, United States, from April 2018 to December 2019. As expected, we detected no difference in cotton rat recruitment. However, contrary to our prediction, the same was true for cotton mice (Peromyscus gossypinus) and oldfield mice (Peromyscus polionotus). We found RIFA removal increased survival both of cotton rats and cotton mice, increasing average population rate of change (λ) on treated sites during the study period. In contrast, we observed lower survival of oldfield mice, with similar λ estimates on treated and untreated sites, but low sample sizes were problematic for this species. Our results show that removal of invasive species can have positive impacts for native species, but both the magnitude of RIFA effects on small mammals and mechanisms by which impacts occur are complex.

Сосудистые эпифиты – растения, порвавшие с землей

Article

Full-text available

Oct 2021
ZH OBSHCH BIOL

В обзоре, первом на русском языке, затронуты вопросы экологического и ботанического феномена эпифитизма сосудистых растений. Обсуждается проблема происхождения эпифитизма, его экологических границ и современного понимания экоморфологических особенностей эпифитов. Рассмотрены различные подходы к классификации эпифитов, включая авторские, обсуждается соотношение современной англоязычной терминологии и традиционной для русскоязычной литературы. Обсуждены наиболее дискуссионные проблемы в понимании феномена эпифитизма в мировой литературе. Рассмотрены механизмы существования растений, порвавших с наземными источниками минерального питания и воды. Изложена проблематика и степень изученности САМ (crassulacean acid metabolism) у эпифитов в контексте их ксероморфоза. Рассмотрен механизм и функциональная роль образования подвешенных почв. Отражены существующие теории и дискуссионные проблемы минерального питания эпифитов, в частности азотного питания. Обобщены различные биологические аспекты освоения крон: диаспорология, строение эпифитных сообществ и экосистемная роль эпифитов.

Μορφολογία, οικολογία και συμπεριφορά των κόκκινων δασικών μυρμηγκιών στη Βόρεια Ελλάδα

Thesis

Nov 2020

Angelos Tsikas

Ο ρόλος των κόκκινων δασικών μυρμηγκιών στο δασικό οικοσύστημα είναι πολύ σημαντικός, επηρεάζοντας τον αριθμό και την αφθονία των ειδών της πανίδας, τη διασπορά και την αύξηση της χλωρίδας, και το αβιοτικό περιβάλλον. Η σπουδαιότητά τους για το δασικό οικοσύστημα ήταν ήδη γνωστή από το 19ο αιώνα, και έχει μελετηθεί στα δάση της Β. Ευρώπης. Στα δάση της Μεσογείου, όπου υπάρχει μεγαλύτερη βιοποικιλότητα και οι δασοκομικές πρακτικές διαφέρουν, ενώ υπάρχουν κάποιες αναφορές για την ύπαρξή τους, ελάχιστα έχουν όμως μελετηθεί. Η παρούσα έρευνα είχε σκοπό τη μελέτη της μορφολογίας των πληθυσμών των κόκκινων δασικών μυρμηγκιών στην Ελατιά Ν. Δράμας και στον Λαϊλά Ν. Σερρών και των αλλομετρικών κανόνων που ισχύουν σε αυτούς, καθώς και ως προς την επίδραση των φωλιών τους στο δασικό έδαφος που βρίσκεται πέριξ των φωλιών. Για να επιτευχθούν οι στόχοι συλλέχθηκαν εργάτριες από 30 φωλιές από τους δύο πληθυσμούς, καθώς και δείγματα εδάφους από 5 φωλιές και το περιβάλλον έδαφος. Και στους δύο πληθυσμούς βρέθηκε μεγάλο εύρος μεγεθών και τα διάφορα όργανα βρέθηκε να έχουν αρνητικές αλλομετρικές σχέσεις με το συνολικό μέγεθος. Οι αλλομετρικές σχέσεις διαφέρουν όμως μεταξύ των πληθυσμών. Το pH βρέθηκε να αυξάνεται σταδιακά όσο πλησιάζουμε στη φωλιά, η οποία τείνει να το ουδετεροποιήσει. Οι συγκεντρώσεις C και N στο υπέργειο μέρος της φωλιάς βρέθηκαν πολύ υψηλότερες από το έδαφος στο κέντρο της φωλιάς, αλλά και από το έδαφος πέριξ αυτής μειώνονται πιο απότομα όσο απομακρυνόμαστε από αυτήν. Οι υψηλές συγκεντρώσεις είναι μόνο τοπικές στις φωλιές και δε μεταβάλλουν τις χημικές ιδιότητες του δασικού εδάφους συνολικά, αλλά συμβάλλουν στη χωρική ετερογένεια του δασικού εδάφους και στους γεωχημικούς κύκλους.

No evidence of top‐down effects by ants on litter decomposition in a temperate grassland

Article

Full-text available

Jul 2021

Ants play multiple roles in ecosystems, but their ability to affect decomposition processes in temperate grasslands is relatively unknown. We investigated whether the suppression of ant populations influenced litter decomposition in grasslands via predation of some decomposers (e.g., mites and springtails) and/or microbial activity and composition. We performed two successful ant suppression treatments (seven weeks, 37% suppression, year 1, 10 weeks, 70% suppression, year 2) over the course of a 59‐week experiment. We then assayed the effects of ant suppression using coarse‐ and fine‐mesh litterbags and evaluated litter chemistry, microbial and arthropod communities, and microbial enzyme activity. Ant suppression efforts reduced ant abundance and altered ant, arthropod decomposer, and non‐ant predator community composition. However, ant suppression did not affect decomposer arthropod abundance, litter mass loss, microbial composition, or enzyme activity in litterbags. Litterbag mesh size did not alter microbial composition, perhaps due to a failure to exclude decomposers, as mites and springtails were more or equally abundant in fine‐mesh bags. Nevertheless, mesh size did change litter chemistry, suggesting that mesh size‐mediated microenvironments affect decomposition environment regardless of invertebrate exclusion. Coarse‐mesh litterbags had higher concentrations of microbial sugars, lignin, and N and lower concentrations of litter C and crystalline cellulose than fine‐mesh litterbags. Litterbag mesh size may alter decomposition processes irrespective of invertebrate abundance. We found no evidence that ant predation was an important driver of decomposer populations or decomposition in these systems, and we suspect redundancy at the top of the detrital food web dilutes the role of ants.

Hiking Trails Increase Abundance of Harvester Ant1 Nests at Clear Creek, Arizona

Article

Full-text available

Jun 2021
SOUTHWEST ENTOMOL

Diversity and abundance of soil-litter arthropods and their relationships with soil physicochemical properties under different land uses in Rwanda

Article

Apr 2021

Soil-litter arthropods are critical for ecosystem functioning and sensitive to land use change, and hence to the variations in soil physicochemical properties. The relationships between soil-litter arthropod communities and soil physicochemical properties, however, remain poorly studied in Rwanda. We explored the relationships between the families of soil-litter arthropods and soil properties in exotic and native tree species, and in varieties of coffee and banana plantations. Soil-litter arthropods were sampled by using Berlese funnels, hand sorting, and pitfall traps, and were identified to the family level. Soil cores were collected and analysed for soil pH, available phosphorus , total nitrogen, soil organic carbon, silt, clay and sand. A total of 3176 individuals of soil-litter arthropods were collected, identified and classified into 13 orders and 23 families. Higher abundance was found in soil and litter sampled in plots of native tree species and banana plantations compared to exotic tree species and coffee plantations. Higher diversity was found in plots of native and exotic tree species. The analysis of soil physicochemical properties indicated that native tree species offer suitable conditions of studied soil properties. The study of the relationships between the land use, soil properties and families of soil-litter arthropods indicated positive correlations and relationships mainly in native tree species. We conclude that forest with native tree species play an important role in the conservation of soil-litter arthropods and for maintenance of better soil conditions.

Urbanization Effect on the Ant Diversity and Composition in an Arid City

Preprint

Apr 2021

The dramatic increased rates of uncontrolled urbanization in various parts of the World have resulted in loss of native species and overall threats to biodiversity. Over the last few decades Saudi Arabia has witnessed a remarkably rapid population growth and unparalleled levels of urbanization, leading to threats to biodiversity. Ants were pitfall-trapped across an urban-rural gradient to evaluate ant assemblage responses to urbanization in Wadi Hanifa, Riyadh, Central Saudi Arabia. Fifteen sampling sites were selected along three different urbanization gradients, each traversing urban, suburban and rural zones. Within each site 10 traps were distributed and operated for 7 consecutive days, at 3-monthly intervals throughout one year. Vegetation, ground cover, and chemical and physical soil variables at sampling sites were analyzed concurrently. Ant abundance, species richness, evenness, and diversity indices of Shannon and Simpson were calculated for each site using PC-ORD to demonstrate diversity patterns along the urbanization gradients. Ant assemblages were assessed by detrended corresponding analysis (DCA), canonical correspondence analysis (CCA), and analysis of similarity (ANOSIM) using PC-ORD. Indicator species analysis was conducted to define representative species along the urbanization gradient. A total of 42 ant species were identified. The diversity parameters were consistent across the urbanization gradient. However, significant differences were observed in the ant assemblages between rural and urban, suburban and urban, but only marginal between rural and suburban. Eleven ant species were identified as indicator species (IV values between 50.7-80.7%). The ant assemblages were influenced by flora, ground cover, and soil variables.

Anthills as habitat islands in a sea of temperate pasture

Article

Full-text available

Mar 2021
BIODIVERS CONSERV

Ants can shape vegetation as seed dispersers and ecosystem engineers. When anthills are long-lasting, they are known to change soil and vegetation characteristics. However, it is unclear whether plant species traits and species composition vary between ant guilds and between parts of individual anthills. We compared different aspects of soil and vegetation (composition, seedling abundance, and functional traits) between anthills and the surrounding mesophilous pasture in Czechia. This pasture hosts eight ant species, which belong to both seed dispersers and non-dispersers. Where feasible, we divided anthills into centres and margins for the analyses. Anthills (area 90.5–4051.7 cm²; 5–19 plant species) displayed different and more heterogeneous (less similar within anthill plot type) vegetation composition when compared to the surrounding area, with more seedlings and several species restricted to anthills. Further, anthills were more functionally diverse and exhibited several differences in traits, both at the community and intraspecific level. Anthill centres had higher surface temperatures in hot sunny days, higher levels of phosphorus and pH than margins, while margins had higher moisture and carbon content than surrounding vegetation. Further, anthill vegetation differed between ant guilds with more myrmecochorous species found at nests of seed dispersers. Overall heterogeneity in this mesophilous pasture was enhanced by the presence of anthills. Further, the anthills themselves are heterogeneous due to variable sizes, persistence, and differences between their centres and margins on long-lasting anthills. Anthills can thus enhance plant diversity by maintaining disturbed microsites and enhancing the growth of seedlings and less competitive plants.

Day-Night and Inter-Habitat Variations in Ant Assemblages in a Mosaic Agroforestry Landscape

Article

Full-text available

Feb 2021

Throughout the Mediterranean basin, the long-term interaction between human activities and natural processes has led to the formation of unique ecosystems whose biodiversity may be higher than that of the “original” systems. This is particularly true in the case of transformations of continuous stretches of closed forest into a complex mosaic of open and closed habitat over the course of centuries. In this study, we assessed the variation in diversity of ant assemblages in a typical patchy landscape, sampling ants in the three most important constituting habitats: olive plantation, harvested forest, and mature forest. In the study we used two different sampling methods—pitfall traps and observation at baits—which provided information on species presence at different temporal scales. The three habitats displayed different species assemblages, and considerable variation in species composition was observed at different times of the day, particularly in the harvested forest. Functional group analysis showed that the olive plantation, although the most artificial habitat, displayed the highest number of functional groups, suggesting a wider spectrum of available ecological niches for ant species within this habitat type. Overall, it was concluded that each of the three habitats contributes to enhance diversity at the landscape scale, which is greater than that expected from a more homogeneous habitat composition.

Role of ants as dispersers of native and exotic seeds in an understudied dryland

Article

Jan 2021
ECOL ENTOMOL

1. Seed dispersal by ants, i.e. myrmecochory, is important in drylands because ants may contribute to overcoming the typical resource limitation imposed on plants in these environments. Dispersal distance and directed dispersal of seeds to nutrient‐enriched ant nests benefit plants by reducing parent or sibling competition and improving growth, survival, and reproduction. 2. This study investigated the role of ants as seed dispersers in the semi‐arid Patagonian steppe. In particular, this study surveyed native and exotic plants potentially dispersed by ants (i.e. those with nutritive tissues attached to seeds that could attract ants), identified seed disperser ants, and compared their effectiveness as dispersers (i.e. number of removed seeds, transport distance, and seed fate). 3. It was found that 9% of plant species could be potentially dispersed by ants, and field experiments were carried out with five of them (three natives and two exotics). Six ant species dispersed seeds, with Dorymyrmex tener being the most effective seed disperser, interacting preferably with an exotic seed. Finally, the types of nutritive tissues of the seeds are important in determining the attractiveness towards different ant foraging groups. 4. This study's results highlight that ant foraging group and seed's nutritive tissues are relevant traits that could help in understanding ant–seed interactions. Furthermore, in the Patagonian steppe, there are effective seed disperser ants that could play an important role in the distribution of native plants, as well as the spread of invasive species, being especially relevant in nutrient‐poor drylands due to the benefits provided by myrmecochory.

Seeking surrogates for taxonomic and functional evaluations of leaf-litter ant faunas

Article

Full-text available

Mar 2021

Comprehensive biodiversity inventories are expensive and time-consuming to achieve, especially for groups of megadiverse organisms. One approach to resolve such situations is to utilize biological substitutes, referred to as surrogates. A surrogate should provide meaningful information at a lower cost and/or effort than the original level of resolution. Studies have shown that species richness is often not the best or most appropriate component or predictor of biodiversity. Functional diversity can be used as a measurement of the ecological differentiation between habitats or between biological functions. We evaluated the use of several taxonomic metrics as potential surrogates for leaf-litter ant assemblages distributed in 65 Atlantic rainforest sites. Our goal was to find reliable and economic substitutes for both taxonomic and functional leaf-litter ant diversity and composition. We tested four potential surrogate approaches for taxonomic metrics and three for functional group metrics. Additionally, we also evaluated the time and costs involved. We used a large leaf-litter ant database that comprises 364 ant species, respectively classified into 13 or 26 ant functional groups based on either a general and specific resolution. Subfamily was found to be an unacceptable surrogate for both taxonomic and functional group metrics. Mixed-level and indicator taxa metrics were rated as 'excellent' taxonomic surrogates. Mixed-level and genus metrics were rated as 'excellent' or 'acceptable' functional group surrogates when considering the most general functional resolution, while mixed-level and genus were considered as 'excellent' surrogates when considering the more specific resolution. The monetary and time costs to identify ants to genus level were lower than those using indicator taxa and mixed-level metrics. The use of a certain higher taxon functional and taxonomic sur-rogates allows a reduction of survey and analysis costs while still enabling the analysis of biological diversity from the taxonomic and functional point of view.

Fire on the Mountain. Disturbance and Regeneration in Deciduous and Conifer Forests. 20 Years of Experience

Article

Full-text available

Dec 2020

"Fire on the Mountain. Disturbance and Regeneration in Deciduous and Conifer Forests. 20 Years of Experience. Two test and monitoring sites in SW Germany (Forchtenberg) and Leghia (NW Romania) furnish insights to the regeneration modes after fire, clearing, burning, and cultivation -slash and burn - in a deciduous forest or after wildfire in a conifer stand. Forest maps and archivalia helped to reconstruct the forest history of the last 250 years of the Forchtenberg site, which as a heritage still influences the present situation. We could document the autonomous co- evolution of vegetation and soil over two decades. It was done by transects and mapping as well as by soil analysis and micromorphology. The role of soil animals for the weathering of charcoals became evident. The evolution of vegetation and soil after a wildfire could be studied on the Leghia site and compared with the Forchtenberg results. As the Leghia site was not cleared after the fire, it enabled us to follow the stages of decay and of regeneration, where conifers do not play a role. Moreover, one could investigate the effects of grass- and pasture fire, still active in the region. It also evidenced the necessary differentiation of charred material into wood- and grass coal. The indicator values of topsoil/soil surfaces are presented as well as those of charred material for the regeneration stages. Finally, we will discuss the fire risk in deciduous forests under a changing climate. Keywords: Forest disturbance, succession types, forest history, slash and burn, wild fire, charcoal taphonomy, fire risk. "

Lebendige Böden - fruchtbare Böden

Book

Full-text available

Mar 2022

Anna Jacobs

soil life

Estudo de Caso: Impacto Gerado por Formigueiros no Projeto de Fundações de um Centro Universitário no Município de Eusébio Ceará.

Conference Paper

Jan 2020

Analisis Ekosistem Terestrial Taman Buru Masigit Kareumbi

Preprint

Full-text available

Oct 2019

The Ecotoxicity Approach as a Tool for Assessing Vermiremediation Effectiveness in Polychlorobiphenyls, Polychlorodibenzo-p-Dioxins and Furans Contaminated Soils

Article

Full-text available

May 2022

Chemical analyses are inadequate for assessing soil biological quality. Instead, the soil living community can be used both for monitoring and restoring soil health. The aim of this research was to verify vermiremediation efficiency in PCDD/F and PCB contaminated soils from Brescia-Caffaro (Italy), using an ecotoxicity approach. To gauge whether Caffaro soil could sustain a living community, a characterization of the arthropod community was conducted. Earthworms’ suitability for soil bioremediation was assessed applying ecotoxicity tests. Five treatments were set up: 1) contaminated soil; 2) contaminated soil + Eisenia fetida; 3) contaminated soil + Lepidium sativum; 4) contaminated soil + E. fetida + L. sativum, 5) uncontaminated soil + E. fetida. The ecotoxicity tests were: L. sativum germination index and root elongation inhibition, and Folsomia candida survival and reproduction, applied on soil and elutriate on: starter soil (T0), after 56 and 112 days (T56 and T112), the last after water percolation. Soil arthropod community was dominated by Hypogastruridae, Oribatida and, to a lesser degree, Formicidae and Coleoptera larvae. Ecotoxicity tests showed that F. candida reproduction and L. sativum root elongation were more adversely affected by pollutants than survival and germination. The higher soil ecotoxicity at T112 than at T56, suggested higher contaminant bioavailability after water addition. F. candida showed more variability between soil and elutriate than L. sativum. Both bioassays suggested earthworm treatment as the most promising. The importance of selecting different organisms in soil ecotoxicity monitoring, and the role of elutriate like a solid phase complement, was highlighted.

Orman Karıncalarının (Formica rufa grup) Mikroeklembacaklı Komünite Yapısına Etkisi

Article

Full-text available

Dec 2021

Meriç Çakir

Ant crickets and their secrets: Myrmecophilus acervorum is not always parthenogenetic (Insecta: Orthoptera: Myrmecophilidae)

Article

Oct 2021

Previously considered as a thelytokous parthenogenetic species, the widespread ant cricket Myrmecophilus acervorum actually turns out to have a mixed reproductive system: our recent surveys in the central part of its distribution area has revealed the presence of both sexes. Detailed morphological and morphometric descriptions of the previously unknown males are here provided. New data on species distribution in south-eastern Europe are presented, including the first records of M. balcanicus in Bulgaria and of M. nonveilleri in Bulgaria and Hungary. Phylogenetic and phylogeographic analyses have revealed several haplotypes of M. acervorum in Europe, with six of them forming a parthenogenetic clade in populations distributed west of the Carpathians. We tested our samples for bacterial infection by Wolbachia and, surprisingly, Wolbachia was identified only in populations with both sexes and no amplification was obtained from parthenogenetic populations. Phylogenetic analyses performed with sequences pertaining to five nominal species related to M. acervorum, yielded topological congruent trees with four well-supported groups: one group with M. acervorum samples, the second group with M. nonveilleri samples, the third group with M. fuscus and M. gallicus samples, and the fourth group with samples of M. balcanicus. We performed species delineation tests on our sequences, which delimited between four to seven putative species.

Functional composition of ant assemblages in habitat islands is driven by habitat factors and landscape composition

Article

Full-text available

Oct 2021

Fragmented natural habitats within human-transformed landscapes play a key role in preserving biodiversity. Ants as keystone species are essential elements of terrestrial ecosystems; thus, it is important to understand the factors influencing their presence. In a large-scale multi-site study, we surveyed ant assemblages using sweep netting and D-vac sampling on 158 ancient burial mounds preserving grassland habitats in agricultural landscapes in East-Hungary. We asked the following questions: (1) How do habitat factors and landscape composition affect species richness and functional diversity of ants? (2) Which ant traits are affected by habitat factors and landscape composition? Despite their small sizes, mounds as permanent and relatively undisturbed landscape elements could provide safe havens for diverse ant assemblages even in transformed agricultural landscapes. The complex habitat structure of wooded mounds supported high species and functional diversity of ant assemblages. Ant species on wooded mounds had small or medium-sized colonies, enabling the co-existence of more species. The effect of landscape composition on ant assemblages was mediated by habitat factors: steep slopes buffered the negative effect of the cropland matrix and enabled higher ant diversity.

Soil recovery of alluvial gold mine spoils in the Peruvian Amazon using Stylosanthes guianensis, a promising cover crop

Article

Full-text available

Oct 2021

The Amazon is an important reservoir of biodiversity and carbon but it is under pressure by multiple threats such as artisanal and small‐scale gold mining (ASGM). In Peru ASGM has degraded 90,000 ha of old growth forest since the eighties, leaving vast areas as wastelands. As most ASGM in the region is illegal, efforts to recover degraded areas have been scant. Here we assessed the potential of Stylosanthes guianensis to recover soil health as a first step in the restoration of gold mine spoils in a Native community and a mining concession in Madre de Dios, Peru. We evaluated plant growth and analyzed changes in physical, chemical and biological soil parameters. After 470 days after sowing, average plant height was 46.7 cm with a survival rate > 50% and yields of 23.9 t ha−1 and 450 kg ha−1 of dry biomass and nitrogen, respectively. Multiple soil parameters increased significantly, including cationic exchange capacity (3.3 to 4.0 cmol [+] kg−1), soil organic matter (0.03 to 0.39%), soil respiration (0.02 to 0.06 mg CO2 g−1 d−1) and biomass (0.03 to 0.15 mg C g−1). Soil macrofauna increased from 2 to 11 taxonomic groups, including ants, considered as soil engineers. Furthermore, S. guianensis increased soil carbon sequestration of impacted areas from 0.004 t C ha−1 by more than 1650%, up to 0.07 t C ha−1. These promising findings clearly illustrate S. guianensis potential to kick‐start natural succession of Amazonian forests after degradation by ASGM and hence help achieving the Sustainable Development Goals.

Abundance and biodiversity of soil mesofauna in different layers of conifers forest soils

Article

Full-text available

Aug 2021

In order to investigate the diversity and population fluctuations of soil mesofauna (Acari and Collembola) of conifers (cypress and pine trees) at Ilam province, Iran, soil samples monthly (0–5 and 5–10 cm) were collected during September 2018 to September 2019. The soil mesofauna were extracted using a Berlese funnel and they were counted and identified. The number of arthropods was compared in different soil layers and in different seasons of the year. The analysis of variance of data showed that soil layers and seasons had significant effect on the population densities of soil mesofauna in both cypress and pine trees (P≤0.01), but their interaction did not vary significantly. Based on the means comparisons, the highest and the lowest values of population density of soil mesofauna were belonged to cypress trees with values of 26.5±8.22 (at autumn) and 0.74±0.15 (at summer). In addition, based on the mean comparison, the highest and the lowest amount of population density of soil mesofauna in pine trees were 4.31±1.26 (at autumn) and 0.63±0.14 (at spring). Diversity of arthropods was calculated by using biodiversity indices. The results showed that the most diversity of species based on Shannon-Wiener and Simpson indices observed in seasons and sampling area (cypress and pine trees) with values of 3.77 and 0.97 for pine and summer time and the least diversity detected with 2.44 and 0.83 for cypress and spring time, respectively. Also, the highest amount of species richness of Margalef (11.68) related to the soil of pine trees in autumn season and lowest amount (7.89) related to the soil of cypress trees in spring season. The highest values of Pielou evenness index (0.97) related to soil of pine trees in summer time and lowest value (0.64) related to the soil of cypress trees in spring time. Generally, the calculated biodiversity indices in the soil of pine trees were higher than in the soil of cypress trees, which could be more widely used in the forestry system

Biodiversity of Soil Macrofauna in Jelutong (Dyera lowii Hook.F) based Agroforestry System on Peatlands

Article

Full-text available

Jul 2021

Effects of rainforest transformation to monoculture cash crops on soil living ants (Formicidae) in Jambi Province, Sumatra, Indonesia

Article

Full-text available

May 2021

Abstract. Ants (Formicidae) are fundamental components of almost every terrestrial ecosystem, especially in the tropics. While epigaeic ants are extensively studied, hypogaeic, soil living ants are still neglected to a large extent. To remedy this, in this paper we explore the effects of rainforest transformation cash crop monocultures on abundance, richness and community composition of soil living ants (Formicidae). Ants in this study were procured as a by-product of extensive sampling of soil meso- and macrofauna along a land-use gradient from lowland rainforest via jungle rubber to monocultures of rubber and oil palm in Jami Province, Sumatra, Indonesia. Sampled in 32 plots of 50 * 50 m each, with three 16 cm * 16 cm * 5 cm soil cores each, we collected 2.079 worker ant individuals, belonging to 90 morphospecies from 37 genera and six subfamilies. Land use had a significant effect on abundance and richness, while distance-based community composition was not affected. Cumulatively, lowland rainforest had the highest number of ant species exclusively living in it, and the highest average ant abundance, although multiple comparison tests did not detect significant differences. We also found highest species richness in the lowland rainforest in one of the two investigated landscapes, while not significantly different from the agricultural systems in the other. High abundance variances among the sample sites suggest inadequacy of the sampling method, however. Despite that, our study provides a first glimpse into hypogaeic ant community responses to rainforest conversion to cash crop monocultures in Sumatra, Indonesia.

Forest Succession and Tree Identity Shape Species and Functional Group Richness of Ant Communities in New England

Article

Feb 2021

Effects of mound building Lasius flavus on organic carbon and nutrient fluxes in soils of temperate grassland ecosystems

Article

Nov 2020
PEDOBIOLOGIA

Ants that build long-lasting mounds and move large amounts of mineral soil may influence the composition and fluxes of soil solutions, and thus soil nutrient cycling. However, studies quantifying such effects are scarce. In central Europe, the yellow meadow ant (Lasius flavus) is a common species that changes the character of extensively managed grasslands by its mound building activity. In total, sixteen mound-control pairs were selected within four plots on two grassland sites in Thuringia, Central Germany and monitored from 2013 to 2016. On each plot, bulk precipitation and soil solutions were collected via two open funnel samplers and eight suction plates to determine input and loss fluxes of dissolved organic carbon (DOC), nitrogen (DN), and base cations under L. flavus mounds and control locations. Effects of L. flavus mounds on soil microclimatic conditions were also investigated. In comparison to the controls, L. flavus mounds were characterized by slightly lower soil temperatures and always lower soil moisture. The main driver of lower fluxes of DOC and DN from mounds was related to the reduced seepage water flux under mounds compared to the adjacent grassland. Lasius flavus activity increased potassium (K) concentrations and fluxes in soil solutions from mounds in comparison to the controls, independent from plot-specific soil and seepage water flux variability. Increased concentrations of calcium (Ca) and magnesium (Mg) were measured in the soil solutions of the mounds but were generally not associated with higher Ca or Mg fluxes. In conclusion, L. ﬂavus present unique micro-sites within grassland ecosystems by creating mounds that may function as ecosystem control points for the cycling of certain elements, such as K.

Red Wood Ants prefer mature Pine Forests in Variscan Granite Environments (Formica rufa-group)

Preprint

Full-text available

Nov 2020

0 Abstract We used presence/absence data of 5,160 red wood ant nests (RWA; Formica polyctena) acquired in a systematic large-scale area-wide survey in two study areas (≈350 ha) in the Oberpfalz, NE Bavaria, Germany to explore for the first time the influence of variable (e.g., forest type, tree age) and quasi-invariant factors (e.g., tectonics, geochemical composition of the bedrock) on nest size, spatial distribution and nest density for Variscan granites. A combination of the forest type (mature pine-dominated forests (80-140 years) as main variable factor and the geochemical property of the Variscan granites with their high natural Radon potential and moderate heat production as main quasi-invariant factor could explain the high nest numbers in both study areas. In addition, the spatially clustered distribution patterns of the observed nests suggest a strong interaction between nests and their quasi-invariant environment, especially the directionality of the present-day stress field and the direction of the tectonically formed "Erbendorfer Line". In general, such a combination of variable and quasi-invariant factors can be addressed as particularly favorable RWA habitats.

Lycaenid-tending ants can contribute to fitness gain of the infested host plants by providing nutrients

Article

Full-text available

Dec 2020
ARTHROPOD-PLANT INTE

Ground-nesting ant species are known to promote plant growth by soil nutrient enhancement. Camponotus compressus ants regularly visit the extrafloral nectary-bearing, lycaenid-infested cowpea, Vigna unguiculata plants and construct a shelter for the lycaenid caterpillars at the plant base. The present study shows that ants may influence the overall fitness of the infested cowpea plants by providing nutrients via soil and foliar pathways. Total carbon, nitrogen and phosphorous content of ant constructed shelter (ACS) soil of the lycaenid-harbouring plants were assessed, microbes from the ACS soil were isolated and their plant growth promotion ability was evaluated. Nitrate content of the ant faecal matter was estimated and overall plant fitness was assessed in terms of its growth and yield. The results revealed higher content of total C, N and P in the debris and chamber soil of ACS as compared to the control soil from the base of ant-excluded plants. The microbes isolated from the ACS and ant nest soil were found to possess plant growth promotion abilities. Ant faecal matter was found to contain substantial amount of nitrate. The ant-included, lycaenid-infested plants as well as those lacking the caterpillars demonstrated significantly higher number of pods, number of seeds per pod, root length, shoot length, plant height, number of leaves, plant fresh and dry weight as compared to the control plants. Lycaenid caterpillar tending ant species with a high propensity for visiting plants thus have the potential to increase plant fitness by increasing nutrient availability via multiple pathways.

Nest micromorphology of the neotropical mound building ants Camponotus punctulatus and Solenopsis sp

Article

Full-text available

Jan 2006
SOCIOBIOLOGY

Marcela I. Cosarinsky

The micromorphology of the nests of Camponotus punctulatus and Solenopsis sp. located in the same kind of soil is analyzed in petrographic thin sections under a transmitted light microscope. Nests' components are the same fine and coarse materials observed in the surrounding soil, but the soil micromorphology is deeply altered in ant's constructions. Both species show porous structures with abundant mammillate and star shaped voids, suggesting that walls were constructed with piled, round, partially welded, soil units, which are more prominent in recently built constructions and lacking in soil. The birefringence fabric of fine materials is more distinct in nests than in the soil, because of a higher concentration of fine, organic matter masking the soil clay birefringence. The frequency of sand grains is higher in nests of Solenopsis sp. than in C. punctulatus, where it is similar to that observed in soil, demonstrating that Solenopsis sp. differs from C. punctulatus in selecting and concentrating sand in their constructions. The galleries of C. punctulatus nests show coatings of fine, soil matter and silt, whereas the galleries of Solenopsis sp. are not coated. Micromorphological features of some termite nests are compared.

Chemical characteristics of nest refuse of Atta sexdens rubropilosa (Hymenoptera: Formicidae) reared with different substrates

Article

Full-text available

Oct 2007
REV BRAS CIENC SOLO

Leaf-cutting ants (Atta spp.) are widely distributed in South America, and are considered to be important components of the neotropical ecosystems. Several studies have demonstrated the effect of ant-nesting in soil enrichment, thus facilitating vegetation succession. Possibly, this enrichment is due to decomposed organic matter concentration after disposal of nest refuse in the deep soil by the colonies. However, little is known about the chemical composition of refuse material produced by leaf-cutting ants. The present work aimed to compare the macronutrient concentration in nest refuse and leaves of two different harvested plants (Acalypha sp. or Bauhinia sp.) in colonies of Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae) maintained in laboratory. Eight colonies were divided into two groups (n = 4), and each one was maintained with only one feed type. After 30 days of experiment, samples of leaves and refuse were oven-dried at 70 degrees C and subjected to acid digestion for chemical determination of total N, P, K, S, Ca and Mg. Differences in concentrations of macronutrients in both leaves and refuse were compared using ANOVA and T test. Nutrient concentration in the refuse material was consistently higher than in leaves, for both plants. Acalypha sp. leaves showed greater nutrient concentration than those of Bauhinia sp., while the concentration of all refuses were very similar. This indicates an additional enrichment of nutrients in the refuse material by either ant carcasses, fungus cycling or excretions. Results suggest that nests of leaf-cutting ant are important loci of nutrient recycling of the ecosystem. Moreover, the refuse may represent an important factor for chemical enrichment in soils influenced by leaf-cutting ants.

Phenology and causation of nest heating and thermoregulation in red wood ants of the Formica rufa group studied in coniferous forest habitats in Southern Finland.

Article

Full-text available

Jan 1987
ANN ZOOL FENN

In colonies with a worker complement >1M, nest-warming after winter could start as an autocatalytic process and may not require triggering by sunning behaviour. In the colony studied with a thermograph the intranest temperature remained at a stable level, near 30oC in late spring and summer, even when the outside temperature temporarily dropped below freezing point. Nests later producing sexuals maintain a significantly higher inner temperature in spring than nests later producing only worker broods. The nest-warming effect of insolation is more important in small or weak colonies; endogenous nest heating, based on the metabolism of the ants and their clustering behaviour, is more compatible with the observations in the case of vigorous colonies.-from Authors

Jones CG, Lawton JH, Shachak M.. Organisms as ecosystem engineers. Oikos 69: 373-386

Article

Full-text available

Apr 1994
OIKOS

Ecosystem engineers are organisms that directly or indirectly modulate the availability of resources to other species, by causing physical state changes in biotic or abiotic materials. In so doing they modify, maintain and create habitats. Autogenic engineers (e.g. corals, or trees) change the environment via their own physical structures (i.e. their living and dead tissues). Allogenic engineers (e.g. woodpeckers, beavers) change the environment by transforming living or non-living materials from one physical state to another, via mechanical or other means. The direct provision of resources to other species, in the form of living or dead tissues is not engineering. Organisms act as engineers when they modulate the supply of a resource or resources other than themselves. We recognise and define five types of engineering and provide examples. Humans are allogenic engineers par excellence, and also mimic the behaviour of autogenic engineers, for example by constructing glasshouses. We explore related concepts including the notions of extended phenotypes and keystone species. Some (but not all) products of ecosystem engineering are extended phenotypes. Many (perhaps most) impacts of keystone species include not only trophic effects, but also engineers and engineering. Engineers differ in their impacts. The biggest effects are attributable to species with large per capita impacts, living at high densities, over large areas for a long time, giving rise to structures that persist for millennia and that modulate many resource flows (e.g. mima mounds created by fossorial rodents). The ephemeral nests constructed by small, passerine birds lie at the opposite end of this continuum. We provide a tentative research agenda for an exploration of the phenomenon of organisms as ecosystem engineers, and suggest that all habitats on earth support, and are influenced by, ecosystem engineers.

Composition and Trophic Structure of Detrital Food Web in Ant Nest Mounds of Formica aquilonia and in the Surrounding Forest Soil

Article

Full-text available

Mar 1998

Community composition and food web structure of soil decomposer biota in relation to various habitat properties were compared between upper parts of red wood ant (Formica aquilonia) nest mounds and the adjacent forest soil. For a description of trophic structure of the decomposer community in the two habitats, soil decomposers were classified into 14 trophic groups. Classification of the taxa into three habitat preference categories resulted in a clear division of the fauna into either soil or nest specialists, relatively few taxa falling between these two groups. A large majority of the nest specialists belonged to a non-myrmecophilous soil decomposer fauna so far largely overlooked in studies on ant-invertebrate associations. Trophic organisation of the nest mound community differed clearly from that in the soil by having considerably larger biomass at the base of the food web, and less large predators - other than ants - at the top of the web. Contrary to forest soils, the clear dominance of bacterial feeding microfauna over the fungal feeding microfauna in the nest mounds suggests that most of the energy passing through the food web is channelled through a bacterial-based food-web compartment in the nest mounds. Relatively constant temperature and moisture in the nest surface, continuous energy input by the ants to the nests, and ant-induced reduction in predation pressure on macropredators are suggested to be responsible for the development of the typical decomposer community structure in the nest mounds. Thus, the food-web dynamics in ant nest mounds represent an interesting case in which the behaviour of an invertebrate species (i.e. the ant) has a potential to control the development of a system-level organisation. The high biomass of microbi-detritivorous animals, especially earthworms, in the nest mounds suggests that the activities of the decomposer fauna may feed back to the structure of nest mound and indirectly alter the performance of the ant colony.

Effect of ants on sandy soils in semi-arid eastern Australia - Local distribution of nest entrances and their effect on infiltration of water

Article

Full-text available

Jan 1993
AUST J SOIL RES

David J Eldridge

The influence of the funnel ant (Aphaenogaster barbigula) on water infiltration was studied on an aeolian soil in a semi-arid Callitris glaucophylla woodland in eastern Australia. At the study site at Yathong Nature Reserve, densities of up to 37 nest entrances m-2 were recorded in some areas, equivalent to a density of 88 000 entrances ha-1 over small areas or 0.9% of the surface area of the landscape. Seventy-two per cent of the entrances were actively being used by the ants. Steady-state water infiltration on soils with entrances averaged 23.3 mm min-1 which was about four times that on entrance-free soils. As the diameter of the nest entrance increased, water penetrated deeper into the soil. The results provide further evidence that ants have a marked influence on redistribution of water in semi-arid environments.

The role of termites and ants in soil modification: A review

Article

Full-text available

Jan 1990
AUST J SOIL RES

Reviews the literature concerning the effects on soil profile development of ants (Hymenoptera: Formicidae) and termites (Isoptera) in the Australian environment. Their pedological influence is largely through the construction of nests, galleries, soil sheetings and moundings. Termites contribute actively to soil turnover, and the contribution of termite sheetings and ant mounds to soil turnover is being recognized. Termite mounds may persist in the landscape for more than two decades, while ant mound longevity varies from weeks to decades. Ants and termites seem to either increase infiltration by improving soil structure and porosity, or to decrease infiltration by producing compact surfaces which assist runoff and erosion. Other effects involve the chemical alteration of the soil profile by ants and termites collecting and transporting live and dead animal and plant materials to their nest structures, and by the additions of secretions and excreta in nest construction. The majority of ants and termites probably increase C and nutrient levels, especially N, P and K, as well as exchangeable Mg and Ca. -from Authors

Morphological changes in Camponotus punctulatus (Mayr) anthills of different ages

Article

Full-text available

Jun 2006

In north-eastern Argentina, Camponotus punctulatus builds large numbers of big and coherent anthills after abandonment of rice cultivation. These anthills easily reach 1 m in height and 2 m in diameter, and a density of 1800 nests ha−1. We studied the internal morphology of C. punctulatus aged anthills of 4, 6 and 15 years, respectively, by describing and quantifying, meso- and macroporosity of undisturbed soil samples using image analysis. Four different parts were distinguished on these cone-shaped anthills: the loose granular cortex, the summit, the core of the anthill and the base of the anthill at ground level. The percentage of macroporosity in anthills significantly differed between the parts of the anthill, but changed little with age except for the 15 year old anthill that had increased percentages of mesopores and macropores with rounded and irregular shapes. Walls of the chambers and galleries were highly compacted, highlighting intense ant activity in the anthills, although it was localised mainly in the upper central part. After 6 years the anthills became surrounded by a discontinuous peripheral depression, which likely affects water drainage and infiltration. In 15 year old anthills the lateral depressions became a continuous ditch where water accumulates giving place to a constant wetted zone inside the anthill. Our results support the previous consideration of C. punctulatus as an ecosystem engineer, although in this case related to the changes produced on the soil surrounding the anthills which may affect the survival and distribution of other soil organisms.

Ants Create Hummocks and Alter Structure and Vegetation of a Montana Fen

Article

Full-text available

Jan 2009

The ants Formica podzolica, Myrmica fracticornis and M. incompleta commonly build nests in a large peatland complex in N-central Montana. Nests of Formica are much larger than those of Myrmica spp. and occur in a microtopographic mosaic of hummocks and hollows. The large mound nests of F. podzolica and the hummocks are similar in size, and both had elevated levels of K, PO4−, Mg and Na compared to the peatland surface, suggesting that the hummocks are abandoned ant mounds. Ant mounds provide an environment for plants that has better aeration and is warmer as well as nutrient-enriched. A few species of strongly rhizomatous graminoids occur on active mounds, but abandoned nests (hummocks) provide habitat for larger shrubs as well as many species of plants that otherwise could not grow in the cold, nearly saturated peat. Formica workers obtain much of their nutrition by tending aphids that feed on the shrubs growing on hummocks. We hypothesize that this is a positive feedback relationship that has promoted the increase of Formica colonies and allowed them to permanently change the structure and composition of a large portion of the vegetation in this rich fen.

The role of termites and ants in soil modification-a review?

Article

Jan 1990

Nester von Lasius flavus (Hymenoptera, Formicidae)

Article

Jan 1981
PEDOBIOLOGIA

G.M. Dlussky

The contribution of harvester ant nests, Pogonomyrmex rugosus (Hymenoptera : Formicidae), to soil nutrient stocks and microbial biomass in the Mojave Desert (vol 33, pg 599, 2004)

Article

Dec 2004
ENVIRON ENTOMOL

The distribution of soil nutrients in deserts is heterogeneous, with high concentrations of organic and inorganic nutrients occurring under shrubs and near animal dwellings. Attention has focused on shrubs in creating "fertile islands." in this study, we compare the effects of the harvester ant Pogonomyrmex rugosus Emery (Hymenoptera: Formicidae) and shrubs on soil composition in the Mojave Desert. Soil organic matter, total N, mineral N, and available P were significantly more concentrated in the nests of P. rugosus than under the dominant vegetation and in sparsely vegetated interspaces between shrubs and ant nests. Ant nests also contained high concentrations of total C, organic C, and soluble organic C and N relative to other microhabitat types. On an areal basis, ant nests stored 3% of mineral N and 0.7-1.6% of organic matter, total N, and available P on the landscape while covering 0.5% of the surface. At field moisture, microbial biomass C and N were significantly more concentrated in ant nests at one of two study sites. When moistened, ant nest soils had a higher capacity for microbial growth than soils from other microhabitats. As a result of ant activities, ant nests accumulated surface materials at an average rate 3.5 mm/yr faster than the surrounding soil. We conclude that P. rugosus nests impact and ecosystems by creating highly concentrated patches of soil nutrients and microflora on the landscape that could affect biogeochemical cycling rates and plant community dynamics.

The nest architecture of the Florida harvester ant, Pogonomyrmex badius

Article

Jan 2004
J INSECT SCI

Walter R. Tschinkel

The architecture of the subterranean nests of the Florida harvester ant, Pogonomyrmex badius, was studied through excavation and casting. Nests are composed of two basic units: descending shafts and horizontal chambers. Shafts form helices with diameters of 4 to 6 cm, and descend at an angle of about 15-20degrees near the surface, increasing to about 70degrees below about 50 cm in depth. Superficial chambers (< 15 cm deep) appear to be modified shafts with low angles of descent, and are distinct from deeper chambers. In larger nests, they have a looping, connected morphology. Chambers begin on the outside of the helix as horizontal-floored, circular indentations, becoming multi-lobed as they are enlarged. Chamber height is about 1 cm, and does not change with area. Chamber area is greatest in the upper reaches of the nest, and decreases with depth. Vertical spacing between chambers is least in the upper reaches and increases to a maximum at about 70 to 80% of the maximum depth of the nest. The distribution of chamber area is top-heavy, with about half the total area occurring in the top quarter of the nest. Each 10% depth increment of the nest contains 25 to 40% less area than the decile above it, no matter what the size of the nest. Nests grow by simultaneous deepening, addition of new chambers and/or shafts and enlargement of existing chambers. As a result, the vertical spacing between chambers is similar at all nest sizes, and the relative distribution of chamber area with relative nest depth did not change during colony growth (that is, the size-free nest shape was the same at all colony sizes). Total chamber area increased somewhat more slowly than the population of workers excavating the nest. The branching of shafts was consistently shallow (< 40 cm), somewhat more so in large nests than small. Large colonies rarely had more than 4 shaft/chamber series. Each new series contributed less to the total chamber area because its chambers were smaller. Incipient colonies were usually 40 to 50 cm deep while mature colonies were commonly 2.5 to 3.0 m deep. Workers captured near the top of a mature nest ( and therefore older) and penned in escape proof enclosures, excavated larger nests than did young workers captured from the bottom of the nest. Most of this difference was due to a larger fraction of older workers engaging in digging, rather than an increase in their rate of work. All ages of workers produced similar top-heavy nests. When different ages of workers from different levels of a mature colony were allowed to re-assort themselves in a vertical test apparatus buried in the soil, older workers moved upward to assume positions in the upper parts of the nest, much as in the colonies from which they were taken. The vertical organization of workers based on age is therefore the product of active movement and choice. A possible template imparting information on depth is a carbon dioxide gradient. Carbon dioxide concentrations increased 5-fold between the surface and the depths of the nest. A preference of young workers for high carbon dioxide concentrations, and a tendency for workers to dig more under low carbon dioxide concentrations could explain both the vertical age-distribution of workers, and the top-heaviness of the nest's architecture.

Nests of ants and termites influence infiltration in a semi-arid woodland

Article

Jan 1994

David J Eldridge

Ants as agents of the soil habitat changes

Article

Jan 1972

Shell amoebae (Testacea) in ant hill of Formica lugubris: Diversity and population structure

Article

Nov 2006
ZOOL ZH

Shell amoebae (Testacea) population was investigated in soil litter layers and in a Formica lugubris ant hill of (5 samples) situated in a spruce forest, Moscow region. 43 testacean species and subspecies were found totally. The minimal shell number amounted to 11 thous./l g air-dried substrate (surface of the ant hill) and maximal (62 thous.) - in lower litter layer A0H/A1. Fluctuation in species diversity between samples (24-30 species) were insignificant. Representatives of the genera Centropyxis, Cyclopyxis, Plagiopyxis, Corythion and Trinema were among dominants, other species were few in number. Ant hill species complex showed no specificity, being a derivative of the surrounding soil. Distinctions between litter layers and between these layers and the ant hill substrates consisted mainly in population structure changes in the course of plant material decomposition: aerophilous complex of upper layers (Centropyxis aerophila, Trinema lineare being dominants) is substituted by an edaphophilous one (with Plagiopyxis declivis as dominant) in the nest bank of the ant hill and lower litter layers. Plagiopyxis penardi eudominant position in the nest bank is stressed. Special abundance of the species is explained by deep transformation of plant remnants (from moder to mull-like substrate) as the result of ants vital activity.

Influence of ant hills on the meadow soils

Article

Jan 1971
PEDOBIOLOGIA

The interaction between red wood ants, Cinara aphids, and pines. A ghost of mutualism past?

Article

Jan 1991

Biological and chemical properties of fen soils affected by anthills of Myrmica spp.

Article

Jan 2003
POL J ECOL

The paper focuses on the role of ants as soil engineers in three drained fens. Physical, chemical and biotic soil conditions and effects of ants on soil conditions were compared between fens differing in peat origin. Multivariate statistical methods were applied (PCA, RDA). Relationships between soil moisture, indices of soil biological activity, and the amount of nutrients released were better expressed in the anthill soil than in the adjacent soil. A lower bulk density of the anthill soil, thus, a higher soil porosity, enhanced the leaching of water- extractable, mobile metallic cations and nitric ions. The composition of humus fraction was strongly dependent on soil chemical properties. In both the anthill soil and the adjacent soil, the content of humic acids was positively related with bulk density, whereas the content of humins was related with moisture. In adjacent soil, cation exchange capacity (CEC) was positively related with the content of humic acids and with bulk density. This relationship was not so clear in the anthill soil. The direction of changes in these relationships in the anthill soil was influenced by ant societies. The number of individuals in society determined the nest structure and the associated increase in soil humidity and porosity. The consumption by ants, thus the input of matter rich in nitrogen, influenced the functional structure of microorganisms and their activity.

Zur Ernährungsbiologie der Roten Waldameise

Article

Jan 1952

G. Wellenstein

Temperature regulation in nests of the wood ant, Formica polyctena (Hymenoptera: Formicidae)

Article

Jan 1986
ENTOMOL GEN

The distribution and accumulation of nutrients in nests of ant Formica polyctena (Hymenoptera, Formicidae)

Article

Jan 1981
PEDOBIOLOGIA

A.D. Pokarzhevskij

Effect of ants and earthworms on soil habitat modification

Article

Jan 1977

Ant populations, their regulation and effect on soil in meadows

Article

Jan 1980

J. Petal

Organisms as Ecosystem Engineers

Article

Jan 1994
OIKOS

Interactions between organisms are a major determinant of the distribution and abundance of species. Ecology textbooks (e.g., Ricklefs 1984, Krebs 1985, Begon et al. 1990) summarise these important interactions as intra- and interspecific competition for abiotic and biotic resources, predation, parasitism and mutualism. Conspicuously lacking from the list of key processes in most text books is the role that many organisms play in the creation, modification and maintenance of habitats. These activities do not involve direct trophic interactions between species, but they are nevertheless important and common. The ecological literature is rich in examples of habitat modification by organisms, some of which have been extensively studied (e.g. Thayer 1979, Naiman et al. 1988).

The role of nest moisture in thermor??gulation of ant (Formica polyctena, Hymenoptera, Formicidae) nests

Article

Jan 1996
BIOLOGIA

Jan Frouz

The moisture of the nests of the ant, Formica polyctena., and its influence on thermal conductivity, heat capacity and thermal loss of nests were studied. The nest moisture ranged from 4% to 60%. A positive correlation was found between nest moisture and both nest size and shading. Nest moisture seems to be affected by the ants activity, too. Both thermal conductivity and heat capacity were found to be significantly dependent upon the moisture of nest material. Based on these relationships a new method for measuring the thermal loss from ant nests was developed. Significant differences in thermal loss were found between dry and wet ant nests. The heat production by ant metabolism seems to be full sufficient to cover the thermal loss (0.15-4.30 W) in dry nests. In wet nests, however, additional heat production by microbial activity is needed for compensation of the thermal loss being 23.0-35.0 W.

The Influence of Ant Nests on Acacia Seed Production, Herbivory and Soil Nutrients

Article

Feb 1997

Diane Wagner

1 The ant Formica perpilosa nests underneath the shrub Acacia constricta in arid regions of south-western United States. The influence of ant nests on seed production, soil nutrient availability and herbivore protection was evaluated. 2 Plants with basal ant nests were found to produce 1.9 times as many seeds on average than plants of similar size and location without ant nests. Seeds from plants with and without ant nests were equal in fresh mass and were equally likely to germinate. 3 Soil from beneath plants with ant nests contained significantly higher concentrations of nitrate, ammonium, phosphorus, and water than soil from beneath plants without nests. Soil from ant nests also had significantly higher nitrogen mineralization rates. Seed production was not, however, significantly correlated with the concentration of any single soil nutrient measured. Nutrients may interact in ways that benefit plant reproduction. In addition, the microenvironment of ant nest soils may lead to the proliferation of soil organisms beneficial to the plant. 4 Because A. constricta is capable of forming symbioses with nitrogen fixing bacteria, it was predicted that plants with ant nests, exposed to greater concentrations and fluxes of available nitrogen, would utilize more soil nitrogen and less atmospheric nitrogen than plaints without basal nests. Nitrogen isotopic analysis of seed tissue revealed that plants with and without ant nests obtained nitrogen from the same source or combination of sources, suggesting that nitrogen may not have limited A. constricta reproduction. Additional interpretations are also discussed. 5 Ants were much more abundant on plants with ant nests at the base than on those without ant nests, but there was little evidence that proximity to ant nests increased protection against herbivory. Plants with and without basal ant nests sustained similar levels of damage to leaves and seeds. 6 If seed production is correlated with reproductive success, then selection may favour A. constricta plants which harbour Formica perpilosa nests at the base. Enhancement of soil nutrient concentrations may be of general importance in understanding how plants benefit from interaction with ants, especially if ants are more likely to nest near plants bearing extrafloral nectaries.

Effects of Ant Mounds on Soil Chemistry and Vegetation Patterns in a Colorado Montane Meadow

Article

Jun 1983
ECOLOGY

The vegetation and soil chemistry of 15 abandoned mounds of Formica canadensis were compared to control quadrats in a meadow at 2900 m near Gothic, Colorado, USA. Principal Components Analysis indicated the mound vegetation was relatively homogeneous and distinct from nonmound vegetation. Discriminant Analysis indicated that mounds were characterized by Bromus polyanthus and Achillea millefolium, and nonmounds by Poa interior. A parallel analysis of 15 soil chemicals indicated some statistically significant chemical differences between mounds and nonmounds. Several micronutrients (Fe, Zn, Mn), were lower in mounds but were unlikely to be deficient. Ant-dispersed plants (myrmecochores) were almost entirely restricted to nonmound quadrats.

Temperature Distribution and Calorimetric Determination of Heat Production in the Nest of the Wood Ant, Formica Polyctena (Hymenoptera, Formicidae)

Article

Apr 1980
ECOLOGY

This paper describes the temperature and population distribution in the nest hill of the wood ant Formica polyctena. Calorimetric and manometric data on the heat production of ants, pupae, and nest material were used to estimate their possible contribution to the heat balance of the nest hill. The pattern of isothermal lines in the nest did not fully correspond with the population distribution. Oxygen consumption and heat production of the worker ants and pupae steadily with arising ambient temperature. Investigations of the nest material showed a rapid increase in oxygen consumption in spring and a slower decrease in autumn. From spring to autumn the heat production of material from the center of the nest was higher than that of peripheral material. Heat production of the nest material originates in microbial activities and is chiefly the result of aerobic metabolism. The mass-specific heat production of ants is clearly higher than that of nest material. However, considering the total mass of the nest, the rate of heat production of the nest material is more than seven times the heat evolved by the ants. The seasonal fluctuation in the heat production of nest material coincides well with the active phase of the ants. It is conceivable that the nest materials is aerated and loosened by the building actions of the ants, and thus enough nutrient material and optimum conditions are available to the microorganisms.

Red wood ants

Article

Jan 1991
ETHOL ECOL EVOL

Daniel Cherix

On the Foraging Activity of the Wood Ant

Article

May 1955

S. J. Holt

1. The number of foraging workers in a wood ant colony is given by the product of the harmonic mean duration of all round trips made and the number of trips completed per unit time. These two quantities may be estimated by marking and census methods, to facilitate which a simple recording apparatus for use in the field has been developed, and the results obtained are consistent with counts of total population of ant mounds that have been quoted in the literature. 2. A simple mathematical model fits satisfactorily the data available on the distribution of foragers over the trophoporic field of the colony, and prediction of the effects of changes in density of the prey populations has been attempted. The effects of temperature, and also of obstruction to free movement, on the rate at which food is gathered are considered. Distinction is made between the dispersal of nomadic animals and of resident ones which, like ants, return periodically to a home base; some implications of the type of distribution pattern found, as they bear on the determination of the optimum size of a certain type of wildlife reserve, are briefly discussed.

Soil modifications created by ants along a post-fire chronosequence in lichen spruce-woodland

Article

Jan 2002
ECOSCIENCE

Ants appeared to be an important component of the soil fauna in azonal lichen-spruce woodland in southern Québec, but their role in nutrient distribution and vegetation dynamics remained unknown. A study was undertaken to compare physical, chemical, and microbial properties of nest mound soils to those of surrounding soils to test the hypothesis that ants create patches of fertile soil and that these modifications are greater than changes in soil fertility due to forest succession. We also quantified ground cover, sexually regenerated black spruce seedlings, and ant nests along the chronosequence and verified whether nest mounds constituted safe sites for black spruce seedling establishment. Surface nest mounds had a significant effect on most measured soil variables. Compared to surrounding soils, nest soils had lower moisture content and bulk density, higher organic matter content and pH, higher available C for microbial growth, higher plant-available N, and were enriched in several major nutrients (K, Ca, Mg). Extractable-P was, however, lower in nest mounds than in surrounding soils. On the other hand, age-class significantly affected fewer soil variables (moisture, microbial biomass, extractable Na, and total Ca), and these changes could be explained by fire disturbance and the subsequent development of the tree stratum. Exposed mineral soil was the dominant ground cover in the 1-year-old and 9-year-old plots, while lichen cover was dominant in the three older age-classes. Sexually regenerated black spruce seedlings occurred mainly in the sparse moss layer in the 1-year-old and 9-year-old age-classes and almost exclusively in the lichen layer in the two older age-classes. Seedling density was 15 ha-1 the year following fire disturbance, but varied between 52 and 121 ha-1 in the four older age-classes. The average densities of occupied ant nests varied between 137-188 nests ha-1 across age-classes and occured directly in lichen or moss, under bare mineral soil, in coarse woody debris, or under conspicuous sand mounds. We found no seedlings growing on occupied or abandoned nest mounds, which numbered only 15 ha-1 in the 1-year-old age-class and between 44 and 74 ha-1 in subsequent age-classes. We conclude that ants in this lichen-spruce woodland create nutrient-rich patches that can have a positive effect on tree growth and accelerate canopy closure, but we reject the hypothesis that nest mounds are safe sites for black spruce seedling establishment.

Ants create united Europe

Article

Apr 2002
NATURE

John Whitfield

Über den Sozialen Wärmehaushalt der Waldameise (Formica Rufa Var. Rufo-Pratensis For.)

Article

Jan 1924

A. Steiner

1.In dem S. 25 bezeichneten Untersuchungsgebiet ist der optimale Wärmehaushalt der Formica rufa-Staaten während der „guten Jahreszeit“ charakterisiert durch eine Temperaturzone von 23–29°, die in einer Nesttiefe von 15–50 cm dauernd vorhanden ist.Die durchschnittliche Kuppeltemperatur (30 cm-Temperatur) von 25,87° steht rund 10° über der durchschnittlichen Bodentemperatur von 10 cm, die 15,95° beträgt.2.Die Temperaturzone von 23–29° entspricht der optimalen Bruttemperatur von Formica rufa; diese Annahme steht in Übereinstimmung mit der experimentellen Feststellung der Optimaltemperatur für Ameisen durch Fielde (1904) und Herter (1923).3.Bestimmend für den Wärmehaushalt von Formica rufa sind zunächst die physikalischen Wärmefaktoren: Insolation, Lufttemperatur, Wind und Bodentemperatur, wovon die Insolation die allgemeine Grundlage für eine erhöhte Nesttemperatur schafft, also als positiver Wärmefaktor anzusprechen ist, während die drei anderen im allgemeinen einen Wärmeverlust verursachen und deshalb in negativem Sinne auf die Nesttemperatur einwirken. Dabei beeinflussen die Lufttemperatur und der Wind vorwiegend die Kuppeltemperatur, während die Bodentemperatur die Temperatur des Erdnestes bestimmt.Diese aus physikalischen Quellen hervorgehenden Temperatureinflüsse finden eine Ergänzung durch die biologischen Wärmefaktoren:Die Nestameisen verwenden die in der wärmeisolierenden Kuppeldecke angebrachten Ausgänge als Temperaturregulatoren, indem diese Öffnungen bei drohender Abkühlung des Kuppelinneren geschlossen, dagegen bei sich einstellender Überhitzung erweitert werden.Während kühlerer Witterungsperioden, insbesondere während kühleren Nächten, erzeugt der gesammelte Staat eine feststellbare Temperaturerhöhung durch die Produktion von Atmungswärme.Wenn auch als Veranlassung für diese Art von Wärmeerzeugung im allgemeinen eine Reiztemperatur von 10–14° angenommen werden darf, so tritt diese chemische Wärmeregulation doch nicht so gesetzmäßigperiodisch auf, wie dies im überwinternden Bienenstaate der Fall ist.4.Die andauernd gleichmäßige Temperatur von 23–29° kann auch während der „guten Jahreszeit“ bei einer Anzahl von Nestern nicht festgestellt werden. Dies ist besonders der Fall bei jungen Staaten mit kleiner und lockerer Kuppel, bei alternden, lebensschwachen Völkern, die oft in einem übergroßen Neste wohnen, bei Staaten, die unter äußeren Eingriffenleiden und bei Nestern, die unter extremen klimatischen Bedingungen stehen.Diese Staaten sind demgemäß als nicht-optimale Wärmehaushalter zu bezeichnen.4.Die jahreszeitlichen Schwankungen äußern sich im Herbst durch eine bedeutende Erniedrigung der Kuppeltemperatur, die verhältnismäßig stärker sinkt als dies die physikalischen Wärmefaktoren bedingen würden. Die Ursache hierfür liegt in einer starken Abschwächung der Lebenstätigkeit der Ameisen, hervorgerufen durch die Erniedrigung der Umgebungstemperatur (Lufttemperatur) und durch Nahrungsmangel.Im Winter weist der ins Erdnest zurückgezogene und dort in der Kältestarre sich befindliche Formica rufa-Staat keine merkbare Eigentemperatur auf; die Erdnesttemperatur liegt durchschnittlich nur 1/2° über der Bodentemperatur von 30 cm; sie steht aber anderseits in der Regel über dem Gefrierpunkt, so daß die Gefahr des Erfrierens für den überwinternden Staat kaum jemals eintritt.Im Frühling tritt nach und nach wieder die kumulierende Wärmewirkung der Nestkuppel auf, indem die Nesttemperatur innerhalb der Kuppel sich hebt, bis sie sich zuletzt dauernd zwischen 23 und 29° bewegt.

Ant (Formica cinerea) Pedoturbation in a Prairie Soil1

Article

May 1967

The impact of ant bioturbation activities on surrounding soil properties

Article

Dec 2000
PEDOBIOLOGIA

Nest building and foraging activities are two of the many ways that ants impact on the surrounding soil environment within and beyond the mound. These activities have both long- and short-term effects on the soil part of the ecosystem through structural alterations, nutrient accumulation and release, with possible enhancement of soil quality. This study illustrates the impact of ant foraging activities on the soil and the pattern of arrangement existing in soil properties in the mound soil environment. Eight active mounds of Iridomyrmex greensladei, greater than 50 cm in diameter, were randomly selected from four blocks in a vegetation remnant adjacent to the main Wee Waa highway, Narrabri, New South Wales. The soil volume, soil mass and slope for each mound was characterised. Soil samples were collected in the plots at 0–10 cm depth from the top of the mound, the mound perimeter, 5 m radius from the mound perimeter, the foraging tracks, and from other locations unaffected by ant activity. The soil samples were analysed for physical and chemical properties. The extent of pore distribution as cavities and galleries, was evaluated by taking photographs of a cross section of an ant mound after pouring in water miscible paint (1:8 paint to water suspension) into an open cut on the top of the mound. The paint moved through the pores, to a depth of about 150–200 cm from the surface through vertical and lateral galleries. In comparison to the surrounding soil, ant-impacted soils were lower in clay, higher in sand and silt, and lower in exchangeable Ca, Mg, K and Na. The top of the mound was higher in NO3, P and more compacted than soils not modified by ant mounds. Ant-impacted soils had low dispersion indices compared with unmodified soil. Ant bioturbation activities increased soil porosity in the mounds extending to about 200 cm down the soil profile. Ant bioturbation and foraging activities were found to affect soil properties beyond the perimeter of the mound and into the surrounding ecosystem.

The impact of harvester ants on decomposition, N mineralization, litter quality, and the availability of N to plants in the Mojave Desert

Article

Sep 2006
SOIL BIOL BIOCHEM

In arid areas of North America, nests of the seed-harvesting ant Pogonomyrmex rugosus tend to be elevated in mineral nitrogen and other soil nutrients relative to other microhabitats. We investigated the roles of decomposition, N mineralization, and plant nutrient uptake in maintaining high standing stocks of nutrients in P. rugosus ant nests. Decomposition rates of standard cellulose substrates placed on the surface of ant nests and other desert microhabitats suggest that conditions found in ant nests and bare areas are conducive to higher rates of decomposition than conditions under shrubs. In laboratory incubations of moist soil, net N mineralization rates were significantly higher in soil from ant nests than from bare areas and under two of three plant species. Net N mineralization rates measured in situ were much lower than those measured in laboratory incubations, but ant nest soil still exhibited higher rates at one of two sites. Litter collected from ant mounds, composed chiefly of seed chaff, was similar in N content to litter col

The effect of ants on soil properties and processes (Hymenoptera: Formicidae)

Abstract

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