Perennial Colonies Research Articles

A versatile recording device for the analysis of continuous daily external activity in colonies of highly eusocial bees.

As pollinators, bees are key to maintaining the biodiversity of angiosperm plants, and for agriculture they provide a billion-dollar ecosystem service. But they also compete for resources (primarily nectar and pollen), especially the highly social bees that live in perennial colonies. So, how do they organize their daily temporal activities? Here, we present a versatile, low-cost device for the continuous, automatic recording and data analysis of the locomotor activity in the colony-entrance tube of highly eusocial bees. Consisting of an in-house built block containing an infrared detector, the passage of bees in the colony entrance tunnel is registered and automatically recorded in an Arduino environment, together with concomitant recordings of temperature and relative humidity. With a focus on the highly diverse Neotropical stingless bees (Meliponini), we obtained 10-day consecutive recordings for two colonies each of the species Melipona quadrifasciata and Frieseomelitta varia, and also for the honey bee. The Lomb-Scargle periodogram analysis identified a predominant circadian rhythmicity for all three species, but also indications of ultradian rhythms. For M. quadrifasciata, which is comparable in size to the honey bee, we found evidence for a possibly anticipatory activity already before sunrise. As all three species also presented activity at night in the colony entrance tube, this also raises questions about sleep organization in social insects. The cost and versatility of the device and the open-source options for data analysis make this an attractive system for conducting studies on circadian rhythms in social bees under natural conditions, complementing studies on flower visits by these important pollinators.

To be a transit link: Similarity in the structure of colonial system of integration and communication pores in autozooids and avicularia of Terminoflustra membranaceotruncata (Bryozoa: Cheilostomata).

Bryozoan colonies consist of zooids, which can differ in structure and function. Most heteromorphic zooids are unable to feed and autozooids supply them with nutrients. The structure of the tissues providing nutrient transfer is poorly investigated. Here, I present a detailed description of the colonial system of integration (CSI) and communication pores in autozooids and avicularia of the cheilosome bryozoan Terminoflustra membranaceotruncata. The CSI is the nutrient transport and distribution system in the colony. In both autozooids and avicularia it consists of a single cell type, that is, elongated cells, and has a variable branching pattern, except for the presence of a peripheral cord. The general similarity in the CSI structure in avicularia and autozooids is probably due to the interzooidal type of the avicularium. Interzooidal avicularia are likely to consume only a part of the nutrients delivered to them by the CSI, and they transit the rest of the nutrients further. The variability and irregularity of branching pattern of the CSI may be explained by the presence of single communication pores and their varying number. The structure of communication pores is similar regardless of their location (in the transverse or lateral wall) and the type of zooid in contact. Rosette complexes include a cincture cell, a few special cells, and a few limiting cells. Along each zooidal wall, there are communication pores with both unidirectional and bidirectional polarity of special cells. However, the total number of nucleus-containing lobes of special cells is approximately the same on each side of any zooidal wall. Supposing the polarity of special cells reflects the direction of nutrient transport, the pattern of special cells polarity is probably related to the need for bidirectional transport through each zooidal wall. The possibility for such transport is important in large perennial colonies with wide zones of autozooids undergoing polypide degeneration.

Stingless Bee (Apidae: Apinae: Meliponini) Ecology.

Stingless bees form perennial colonies of honey-making insects. The >600 species of stingless bees, mainly Neotropical, live throughout tropical latitudes. Foragers influence floral biology, plant reproduction, microbe dispersal, and diverse ecosystem functions. As tropical forest residents since the upper Cretaceous, they have had a long evolutionary history without competition from honey bees. Most stingless bees are smaller than any Apis species and recruit nest mates to resources, while their defense strategies exclude stinging behavior but incorporate biting. Stingless bees have diversified ecologically; excel in nesting site selection and mutualisms with plants, arthropods, and microbes; and display opportunism, including co-opting plant defenses. As their biology becomes better known, applications to human endeavors are imposing selective pressures from exploitation and approaches to conservation that entail colony extraction from wildlands. Although some meliponines can adjust to new conditions, their populations shall require tropical diversity for survival and reproduction.

Evidence of Nest Reactivation and Perennial Colonies in the Neotropical Bumble Bee Bombus brevivillus (Hymenoptera: Apidae: Bombini).

Bombus brevivillusFranklin is a Neotropical Bombus species whose colonies are disappearing from most of its native range, and little is known about its biology and reproductive habits to help conservation or breeding efforts. Unlike Bombus species from temperate climates whose colonies perish every winter, there are suggestions of perennial colonies that Neotropical Bombus species can present. In this work, we investigated the development of two B. brevivillus colonies (i.e., number of workers, gynes, males, new cocoons, and brood area) between August 2012 and March 2013. We realized that while one colony collapsed and died after the males' and gynes' production, and the reduction of numbers of adult workers, in the other, a new queen assumed the posture at this phase and reactivated the old nest. Despite the reduced number of colonies investigated, this study shows the possibility of nest reactivation in the studied species in queen supersedure events in resemblance to perennial colonies of eusocial bees like Apis species and stingless bees. Such behavior has never been directly described to B. brevivillus in previous studies and opens the possibility for further research in the existence and the extension of perennial colonies in Neotropical Bombus species due to its importance to the species conservation in the tropical environment.

Seasonal Phenology and Colony Longevity Patterns in a Predatory Social Wasp

Social wasps play critical ecological roles in an ecosystem, providing a diversity of services and some disservices. Yellowjacket wasps (Vespula spp.) in particular are well known for shaping arthropod communities via predation and competition for resources. In part due to their sociality and large colony sizes, Vespula can have a profound ecological impact on local communities. Such effects can be magnified when colonies exhibit a perennial life history, in which a colony will overwinter, persist for more than one year, and become orders of magnitude larger in size compared to typical annual colonies. Despite growing interest in the factors that influence colony success, we currently lack the ability to predict when yellowjackets may have a high-abundance or outbreak year. This highlights the need for a critical understanding of the phenological patterns of foraging activity, colony distribution, and senescence. Here, we quantify the seasonal activity and foraging rates of 123 colonies of the western yellowjacket, V. pensylvanica, in its native range over 4 consecutive years. Average colony longevity was about 1 month longer than previously reported for this species, and colonies with later peaks in activity and higher average traffic rates persisted longer into the winter. Longer-lived colonies tended to cluster together within a year, but not between years. We found 3 perennial colonies (2.4% of all colonies), and they exhibited tenfold higher peak traffic rates compared to annual colonies. By identifying temporal and spatial patterns in survivorship and colony longevity, we gain insight into the factors associated with prolonged survival time and increased likelihood of overwintering in yellowjacket wasps.

Social structure of perennial Vespula squamosa wasp colonies.

Many social species show variation in their social structure in response to different environmental conditions. For example, colonies of the yellowjacket wasp Vespula squamosa are typically headed by a single reproductive queen and survive for only a single season. However, in warmer climates, V. squamosa colonies sometimes persist for multiple years and can grow to extremely large size. We used genetic markers to understand patterns of reproduction and recruitment within these perennial colonies. We genotyped V. squamosa workers, pre‐reproductive queens, and males from perennial colonies in the southeastern United States at 10 polymorphic microsatellite loci and one mitochondrial DNA locus. We found that V. squamosa from perennial nests were produced by multiple reproductives, in contrast to typical annual colonies. Relatedness of nestmates from perennial colonies was significantly lower than relatedness of nestmates from annual colonies. Our analyses of mitochondrial DNA indicated that most V. squamosa perennial colonies represented semiclosed systems whereby all individuals belonged to a single matriline despite the presence of multiple reproductive females. However, new queens recruited into perennial colonies apparently mated with non‐nestmate males. Notably, perennial and annual colonies did not show significant genetic differences, supporting the hypothesis that perennial colony formation represents an instance of social plasticity. Overall, our results indicate that perennial V. squamosa colonies show substantial changes to their social biology compared to typical annual colonies and demonstrate variation in social behaviors in highly social species.

Viral load, not food availability or temperature, predicts colony longevity in an invasive eusocial wasp with plastic life history

Social insect colonies exhibit a variety of life history strategies, from the annual, semelparous colonies of temperate bees and wasps to the long-lived colonies of many ants and honeybees. Species introduced to novel habitats may exhibit plasticity in life history strategies as a result of the introduction, but the factors governing these changes often remain obscure. Vespula pensylvanica, a yellowjacket wasp, exhibits such plasticity in colony longevity. Multi-year (perennial) colonies are relatively common in introduced populations in Hawaii, while source populations in the western United States are typically on an annual cycle. Here, we use experiments and observational data to examine how diet, disease, nest thermal environment, and nest location influence colony longevity in a population with both annual and perennial colonies. Counter to our predictions, experimental feeding and warming did not increase colony survival in the winter in the introduced range. However, Moku Virus load and wasp colony density predicted colony survival in one year, suggesting a potential role for disease in modulating colony phenology. We also found that local V. pensylvanica colony density was positively correlated with Moku Virus loads, and that Arsenophonus sp. bacterial loads in V. pensylvanica colonies were positively associated with proximity to feral honeybee (Apis mellifera) hives, suggesting potential transmission routes for these poorly understood symbionts. The factors influencing colony longevity in this population are likely multiple and interactive. More important than food availability, we propose winter precipitation as a critical factor that may explain temporal and spatial variation in colony longevity in these invasive wasps.

Stingless bees in urban areas: low body size and high frequency of diploid males at mating congregations of Nannotrigona perilampoides (Hymenoptera: Meliponini) in Mérida, Yucatán, México

In temperate regions of the world dominated by intensive agriculture, cities harbor a rich diversity and abundance of bee species, often exceeding those of the rural environment. In less industrialized tropical countries, in contrast, stressful conditions may exist in cities for bees with perennial colonies such as stingless bees because of the lack of resources such as amenity green spaces (flowers) and appropriate nesting sites. Yet, we currently lack studies on the ecology of bees in tropical urban areas to test this idea. Here, we compared the body size (as a possible indicator of floral resource supply) and the frequency of diploid males (as a measure of inbreeding) of a widespread stingless bee, Nannotrigona perilampoides, at mating congregations within the city of Merida, Yucatan, Mexico, and in surrounding rural areas. We found that males in Merida were significantly smaller compared with those in rural areas. While diploid males were found in both in the city and rural congregations, their frequency was significantly higher in urban sites. Our results suggest that the performance of colonies of N. perilampoides is poorer in tropical urban compared with rural sites, possibly as a consequence of limited resources and mating among a small number of colonies. We discuss the implications of these findings for the survival and fitness of stingless bees in the tropics.

Evaluating competition for forage plants between honey bees and wild bees in Denmark.

A recurrent concern in nature conservation is the potential competition for forage plants between wild bees and managed honey bees. Specifically, that the highly sophisticated system of recruitment and large perennial colonies of honey bees quickly exhaust forage resources leading to the local extirpation of wild bees. However, different species of bees show different preferences for forage plants. We here summarize known forage plants for honey bees and wild bee species at national scale in Denmark. Our focus is on floral resources shared by honey bees and wild bees, with an emphasis on both threatened wild bee species and foraging specialist species. Across all 292 known bee species from Denmark, a total of 410 plant genera were recorded as forage plants. These included 294 plant genera visited by honey bees and 292 plant genera visited by different species of wild bees. Honey bees and wild bees share 176 plant genera in Denmark. Comparing the pairwise niche overlap for individual bee species, no significant relationship was found between their overlap and forage specialization or conservation status. Network analysis of the bee-plant interactions placed honey bees aside from most other bee species, specifically the module containing the honey bee had fewer links to any other modules, while the remaining modules were more highly inter-connected. Despite the lack of predictive relationship from the pairwise niche overlap, data for individual species could be summarized. Consequently, we have identified a set of operational parameters that, based on a high foraging overlap (>70%) and unfavorable conservation status (Vulnerable+Endangered+Critically Endangered), can guide both conservation actions and land management decisions in proximity to known or suspected populations of these species.

Rediscovering the eusocial sweat bee Lasioglossum marginatum (Hymenoptera: Halictidae) in Sicily through DNA barcoding

Sicily (Italy) is an important hotspot diversity for bees and new species records are constantly reported for the island. Here, we rediscovered after 45 years without records, the occurrence in Eastern Sicily of Lasioglossum marginatum (Brullé 1832) confirmed by DNA barcoding. This is the only known species of eusocial sweat bees (Halictidae) with perennial colonies. Since a single female was collected in our large 2-years bee sampling, combined with its absence in previous collections, this species is suggested to be rare in Sicily.

Annual survival rate of tropical stingless bee colonies (Meliponini): variation among habitats at the landscape scale in the Brazilian Atlantic Forest

Stingless social bees live in perennial colonies whose longevity is influenced by various ecological factors. This study analyzed the influence of habitat anthropization and native forest regeneration stage on the longevity of natural colonies at the landscape scale. Random sampling of 25x25m plots, totaling 30ha per habitat type, located and monitored 118 nests of 14 species in the forest and 105 nests of six species in the anthropic habitat. Significant differences in colony longevity were observed between young and long-lived forests and between long-lived forests and anthropized habitat. Shorter longevities have generally been associated with a set of smaller-bodied species residing in anthropized habitats. The greatest longevities were associated with the three abundant and exclusive forest species, and was similar in the two forest regeneration stages: Melipona scutellaris, Scaptotrigona xanthotricha and Scaptotrigona bipunctata had high annual survival rates ranging from 87% to 93%. Another abundant species in the landscape was Tetragonisca angustula, a small habitat-generalist with short longevity (63%) that varied among habitats. Euclidean distance analysis based on this generalist placed young forest closest to anthropic habitat, and grouped the replicates of long-lived forest. Considering spatial variation in the life history traits, we infer that, among prospective landscape habitats, the Atlantic Forest favors stingless bees with high colonial longevity. On the other hand, generalists, such as T. angustula, with shorter colonial longevity and high reproduction rates are being favored by the expansion of anthropized habitats in place of deforested areas.

Many small rather than few large sources identified in long-term bee pollen diets in agroecosystems

Bees provide essential ecosystem services such as crop pollination, but perennial colonies of social species require year-round access to floral resources, especially in resource-poor agricultural landscapes. We investigated pollen resources used by a social bee (Tetragonula carbonaria, Meliponini) in forests and orchards of subtropical Australia. Pollen DNA metabarcoding with the markers rbcL and ITS2 was used to identify hive pollens from 57 colonies collected at seven sites each season over two years. We identified 341 botanical sources of hive pollens from 37 orders, 72 families, 218 genera and 302 species. Interestingly, introduced species (e.g. Ageratum spp. and Raphanus spp.) and wind-pollinated plants (Poaceae, Cyperaceae) were common pollen sources in both orchards and forests. Orchard colonies used a subset of pollen species used by colonies in forests, with many Myrtaceae (Corymbia, Eucalyptus and Melaleuca spp.), Poaceae, Asteraceae, Fabaceae and Proteaceae species found in both land uses. We found T. carbonaria foraged on “many small” rather than a “few large” pollen sources each season, regardless of land use. This suggests stingless bees aim for diversity in pollen diets. As such, land managers and beekeepers should ensure colonies have access to a variety of floral resources year-round. This may be achieved through targeted planting of key families identified in this study (e.g. Proteaceae, Asteraceae, Myrtaceae, Poaceae, Brassicaceae, Araliaceae, Cannabaceae, Arecaceae, Rubiaceae and Sapindaceae) and / or maintaining weeds while they are flowering in the orchard. Land managers may consider planting in unproductive areas such as riparian zones, edges or between crop rows if space is limited.

Stingless Bees (Melipona subnitida) Overcome Severe Drought Events in the Brazilian Tropical Dry Forest by Opting for High-Profit Food Sources.

In the Brazilian Tropical Dry Forest, the Caatinga, stingless bees (Apidae, Meliponini) need to adjust their foraging behavior to a very short and unpredictable blooming period. Melipona subnitida Ducke 1910 is one of the few meliponine species adapted to the environmental peculiarities of this biome. To get an insight into how these highly eusocial bees are able to maintain their perennial colonies despite extended periods of food scarcity, we asked the following questions: (1) At which plant species do colonies of M. subnitida collect their food during the rainy season? And (2) are there any plant species during the dry season, from which the colonies may profit for replenishing their food stores? During 1year, we collected monthly honey and pollen samples from recently built storage pots of five colonies of M. subnitida and identified the botanical origin of the collected resources. In the course of our study, the colonies foraged at native trees, shrubs, and herbaceous species, demonstrating the importance of all plant strata for the bees' diet. Profitable plants, which bloom mainly during the rainy season and usually produce a great number of flowers, were frequently sampled in new pots throughout the entire study, even during the dry season. From our results, we compiled a list of the most important plant species providing floral resources for bees throughout the year, including periods of drought. We recommend these plants for restoration areas to improve the conservation of native bee species and local beekeeping in the Brazilian Tropical Dry Forest.

Architectural design of stingless bee hives

Stingless bee colonies were collected from different altitudes of Upper Subansiri district of Arunachal Pradesh and Nagaland. Thirty four colonies of Lepidotrigona arcifera were successfully domiciled. Three hive types were designed, viz., Mo = Natural hive (NH), M1= Bamboo hives (BH) and M2 = Log artificial hive (LAH) for better establishment of colonies. These were kept at two heights [two feet above the ground (Ho) and five feet (H1) above the ground]. Wooden hives yielded 665 ml/hive/season as compared to bamboo and natural hives. The rate of colony establishment was best in wooden hive followed by natural hive. Bamboo hive failed to establish perennial colony while wooden hives performed better.

Seasonal variation of a plant-pollinator network in the Brazilian Cerrado: Implications for community structure and robustness.

Seasonal variation in the availability of floral hosts or pollinators is a key factor influencing diversity in plant-pollinator communities. In seasonally dry Neotropical habitats, where month-long periods of extreme drought are followed by a long rainy season, flowering is often synchronized with the beginning of precipitation, when environmental conditions are most beneficial for plant reproduction. In the Brazilian Cerrado, a seasonally dry ecosystem considered one of the world’s biodiversity hotspots for angiosperms, plants with shallow root systems flower predominantly during the rainy season. Foraging activity in social bees however, the major pollinators in this biome, is not restricted to any particular season because a constant supply of resources is necessary to sustain their perennial colonies. Despite the Cerrado’s importance as a center of plant diversity, the influence of its extreme cycles of drought and precipitation on the dynamics and stability of plant-pollinator communities is not well understood. We sampled plant-pollinator interactions of a Cerrado community weekly for one year and used network analyses to characterize intra-annual seasonal variation in community structure. We also compared seasonal differences in community robustness to species loss by simulating extinctions of plants and pollinators. We find that the community shrinks significantly in size during the dry season, becoming more vulnerable to disturbance due to the smaller pool of floral hosts available to pollinators during this period. Major changes in plant species composition but not in pollinators has led to high levels of turnover in plant-pollinator associations across seasons, indicated by in interaction dissimilarity (<3% of shared interactions). Aseasonal pollinators, which mainly include social bees and some solitary specialized bees, functioned as keystone species, maintaining robustness during periods of drastic changes in climatic conditions.

Stingless bees and their adaptations to extreme environments.

Nearly half of all terrestrial tropical ecosystems around the globe comprise dry forests, characterised through elevated temperatures all year round, and short rainy seasons at irregular intervals. The consequent water deficit over several consecutive months limits the availability of floral resources to often very brief and unpredictable periods, which poses a challenge to the maintenance of perennial colonies in highly eusocial bees. Thus, only few highly eusocial bees occur permanently in tropical dry forests, among them some highly adapted species of stingless bees (Apidae, Meliponini). In the present review, we discuss the current knowledge on the adaptations to such extreme environments in Melipona subnitida, a stingless bee native to the Brazilian tropical dry forest. Key to the success of this species is not so much heat resistance of foragers, as it is the ability to maintain perennial colonies despite extended dearth periods. After several months of drought, M. subnitida colonies are capable of re-establishing fully functional colonies from nests containing only few dozens of workers. This surprising resilience is based on a quick reaction to precipitation-driven increase in floral resource availability, mainly owing to selective foraging at high-profit resources and an immediate up-regulation of brood production once food storage conditions improve.

The Impact of Penguins on the Content of Trace Elements and Nutrients in Coastal Soils of North Western Chile and the Antarctic Peninsula Area

In isolated areas without direct human impact where several species of seabirds nest, transformations affecting the soil come mainly from natural processes, such as chemical enrichment caused by seabirds. Penguins constitute an important bird biomass in the Southern Hemisphere, where they breed in colonies on different sites from 100 to thousands of individuals. The accumulation of trace elements and nutrients in soils within two perennial colonies of Humboldt penguins (Spheniscus humboldti) located in north western Chile and three colonies of Adelie penguins (Pygoscelis adeliae) in the Antarctic Peninsula area were investigated here. Surface soil samples were collected directly from nesting sites. Control samples were taken outside the colonies within sites adjacent to the nesting areas, but not affected by bird excrement. The contents of Cd, Co, Cr, Cu, Mo, Ni, Sr, V and Zn were determined by inductively coupled plasma optical emission spectrometry. Ammonium (NH4) and nitrate (NO3) ions were determined colorimetrically. Extractable potassium (K) was determined by flame emission spectrometry, and available phosphorus (Olsen-P) was determined by spectrophotometry. The highest concentrations of trace metals (Cd, Co, Cr, Cu, Mo, V and Zn) and macronutrients (available N, K and P), along with an increase in salinity and acidity levels, were found directly below the seabird colony, a situation occurring in northern Chile as well as in the Antarctic Peninsula area, highlighting the role that penguins have as bio-vectors on generating geochemical changes in different ecosystems. Some terrestrial plants and animals that live near those penguin colonies might be affected at a greater level than the organisms that live in sites similar but distant from colonies of birds. New data about the role of these species of seabirds as bio-vectors of chemical contaminants are added.

The effects of drainage and restoration of pine mires on habitat structure, vegetation and ants

Habitat loss and degradation are the main threats to biodiversity worldwide. For example, nearly 80% of peatlands in southern Finland have been drained. There is thus a need to safeguard the remaining pristine mires and to restore degraded ones. Ants play a pivotal role in many ecosystems and like many keystone plant species, shape ecosystem conditions for other biota. The effects of mire restoration and subsequent vegetation succession on ants, however, are poorly understood. We inventoried tree stands, vegetation, water-table level, and ants (with pitfall traps) in nine mires in southern Finland to explore differences in habitats, vegetation and ant assemblages among pristine, drained (30–40 years ago) and recently restored (1–3 years ago) pine mires. We expected that restoring the water-table level by ditch filling and reconstructing sparse tree stands by cuttings will recover mire vegetation and ants. We found predictable responses in habitat structure, floristic composition and ant assemblage structure both to drainage and restoration. However, for mire-specialist ants the results were variable and longer-term monitoring is needed to confirm the success of restoration since these social insects establish perennial colonies with long colony cycles. We conclude that restoring the water-table level and tree stand structure seem to recover the characteristic vegetation and ant assemblages in the short term. This recovery was likely enhanced because drained mires still had both acrotelm and catotelm, and connectedness was still reasonable for mire organisms to recolonize the restored mires either from local refugia or from populations of nearby mires.

Population genomics of Sociable Weavers Philetairus socius reveals considerable admixture among colonies

The evolution of sociality often leads to genetic structuring among groups and alters the evolutionary forces that the groups experience. Describing the genetic structuring of social species is, therefore, necessary to understand the selective forces that act on a species. While recent work has used genomic methods to investigate population structure in eusocial insects, relatively little genomic work has examined population structure in the largest non-human mammal and avian clades. We delimited population genetic structuring in Sociable Weavers (Philetairus socius), a passerine that lives in large, stable, perennial colonies, using the genotyping-by-sequencing approach to generate a dataset of several thousand SNPs. We used the SNPs to estimate genetic structuring within and among eight nests. While we document relatively low levels of genetic structuring among nests, the structuring was not explained by distance between nests. We also found significantly higher structuring among male Sociable Weavers compared to female weavers, suggesting that female Sociable Weavers are more prone to dispersal in this species. Not all nests represent distinct genetic groups according to Bayesian clustering analysis, which is unsurprising given the low differentiation among nests, especially compared to other social species. In almost all colonies there was less heterozygosity than expected, possibly due to reproductive skew within each colony.

Black spots for aquatic and terrestrial ecosystems: impact of a perennial cormorant colony on the environment

The global growth of populations of different cormorant species has raised concern on the consequences of their presence in the environment. This study examined the impact of a perennial colony (160 breeding pairs) of great cormorants on terrestrial and aquatic ecosystems. The deposition of bird-originating nutrients within the area of colony, their accumulation in soils and the fluxed of chemical substances to a nearby lake were investigated. The impact of cormorants on terrestrial vegetation and microbial pollution of the lake were also studied. The soils beneath the colony were found to contain extremely high concentrations of nitrogen and phosphorus. The overgrowing vegetation was largely limited with nitrophilous and invasive species being more abundant. Increased loads of organic matter, nitrogen and phosphorus were also found in groundwater and particularly, surface runoff. The colony area delivered significant amounts of nutrients to the lake also when the birds were absent. The lake water near colony was also characterized by increased nutrient content and additionally higher number of faecal bacteria. The present results demonstrate the complexity through which the effect of cormorant colonies can be manifested simultaneously in terrestrial and aquatic ecosystem.