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Carbon-focused climate mitigation strategies are becoming increasingly important in forests. However, with ongoing biodiversity declines we require better knowledge of how much such strategies account for biodiversity. We particularly lack information across multiple trophic levels and on established forests, where the interplay between carbon stocks, stand age, and tree diversity might influence carbon–biodiversity relationships. Using a large dataset (>4600 heterotrophic species of 23 taxonomic groups) from secondary, subtropical forests, we tested how multitrophic diversity and diversity within trophic groups relate to aboveground, belowground, and total carbon stocks at different levels of tree species richness and stand age. Our study revealed that aboveground carbon, the key component of climate-based management, was largely unrelated to multitrophic diversity. By contrast, total carbon stocks—that is, including belowground carbon—emerged as a significant predictor of multitrophic diversity. Relationships were nonlinear and strongest for lower trophic levels, but nonsignificant for higher trophic level diversity. Tree species richness and stand age moderated these relationships, suggesting long-term regeneration of forests may be particularly effective in reconciling carbon and biodiversity targets. Our findings highlight that biodiversity benefits of climate-oriented management need to be evaluated carefully, and only maximizing aboveground carbon may fail to account for biodiversity conservation requirements.

submitted by Carolin Margit Strutzmann & Valentin Titus Schlenz, Masterarbeit Universität Innsbruck 2022

submitted by Carolin Margit Strutzmann & Valentin Titus Schlenz, Masterarbeit Universität Innsbruck 2022

Aim: Temperature, food resources and top-down regulation by antagonists are considered as major drivers of insect diversity, but their relative importance is poorly understood. Here, we used cavity-nesting communities of bees, wasps and their antagonists to reveal the role of temperature, food resources, parasitism rate and land use as drivers of species richness at different trophic levels along a broad elevational gradient. Location: Mt. Kilimanjaro, Tanzania. Taxon: Cavity-nesting Hymenoptera (Hymenoptera: Apidae, Colletidae, Megachilidae, Crabronidae, Sphecidae, Pompilidae, Vespidae). Methods: We established trap nests on 25 study sites that were distributed over similar large distances in terms of elevation along an elevational gradient from 866 to 1788 m a.s.l., including both natural and disturbed habitats. We quantified species richness and abundance of bees, wasps and antagonists, parasitism rates and flower or arthropod food resources. Data were analysed with generalized linear models within a multi-model inference framework. Results: Elevational species richness patterns changed with trophic level from monotonically declining richness of bees to increasingly humped-shaped patterns for caterpillar-hunting wasps, spider-hunting wasps and antagonists. Parasitism rates generally declined with elevation but were higher for wasps than for bees. Temperature was the most important predictor of both bee and wasp host richness patterns. Antagonist richness patterns were also well predicted by temperature, but in contrast to host richness patterns, additionally by resource abundance and diversity. The conversion of natural habitats through anthropogenic land use, which included biomass removal, agricultural inputs, vegetation structure and percentage of surrounding agricultural habitats, had no significant effects on bee and wasp communities. Main conclusions: Our study underpins the importance of temperature as a main driver of diversity gradients in ectothermic or

Aim: Temperature, food resources and top-down regulation by antagonists are considered as major drivers of insect diversity, but their relative importance is poorly understood. Here, we used cavity-nesting communities of bees, wasps and their antagonists to reveal the role of temperature, food resources, parasitism rate and land use as drivers of species richness at different trophic levels along a broad elevational gradient. Location: Mt. Kilimanjaro, Tanzania. Taxon: Cavity-nesting Hymenoptera (Hymenoptera: Apidae, Colletidae, Megachilidae, Crabronidae, Sphecidae, Pompilidae, Vespidae). Methods: We established trap nests on 25 study sites that were distributed over similar large distances in terms of elevation along an elevational gradient from 866 to 1788 m a.s.l., including both natural and disturbed habitats. We quantified species richness and abundance of bees, wasps and antagonists, parasitism rates and flower or arthropod food resources. Data were analysed with generalized linear models within a multi-model inference framework. Results: Elevational species richness patterns changed with trophic level from monotonically declining richness of bees to increasingly humped-shaped patterns for caterpillar-hunting wasps, spider-hunting wasps and antagonists. Parasitism rates generally declined with elevation but were higher for wasps than for bees. Temperature was the most important predictor of both bee and wasp host richness patterns. Antagonist richness patterns were also well predicted by temperature, but in contrast to host richness patterns, additionally by resource abundance and diversity. The conversion of natural habitats through anthropogenic land use, which included biomass removal, agricultural inputs, vegetation structure and percentage of surrounding agricultural habitats, had no significant effects on bee and wasp communities. Main conclusions: Our study underpins the importance of temperature as a main driver of diversity gradients in ectothermic or

The oceans are increasingly affected by multiple aspects of global change, with substantial impacts on ecosystem functioning and food-web dynamics. While the effects of single factors have been extensively studied, it has become increasingly evident that there is a need to unravel the complexities related to a multiple stressor environment. In a mesocosm experimental study, we exposed a simplified, multi-trophic seagrass ecosystem (composed of seagrass, two shrimp species, and two intermediate predatory fish species) to three global change factors consisting of simulated storm events (Storms), heat shocks (Heat), and ocean acidification (OA), and the combination of all three factors (All). The most striking result indicated that when all factors were combined, there was a negative influence at all trophic levels, while the treatments with individual factors revealed species-specific response patterns. It appeared, however, that single factors may drive the multi-stressor response. All single factors (i.e., Storms, Heat, and OA) had either negative, neutral, or positive effects on fish and shrimp, whereas no effect was recorded for any single stressor on seagrass plants. The findings demonstrate that when several global change factors appear simultaneously, they can have deleterious impacts on seagrass ecosystems, and that the nature of factors and food-web composition may determine the sensitivity level of the system. In a global change scenario, this may have serious and applicable implications for the future of temperate seagrass ecosystems.

A resampling of 38 small farmland ponds in Belgium after 10 years revealed a high temporal species turnover for both phytoplankton and zooplankton communities, associated with substantial changes in abiotic factors, especially a reduction in total phosphorus concentration. Across ponds, phytoplankton biomass decreased while evenness and richness increased between the samplings in 2003 and 2013. By contrast, the zooplankton assemblage was characterised by lower biomass, richness and evenness in 2013. Ponds experiencing larger environmental change showed stronger changes in phytoplankton richness and evenness. Resource use efficiency (RUE) of zooplankton increased with greater environmental change and zooplankton evenness, which points to a switch towards species with higher RUE or greater variety in food sources in higher trophic levels. As ponds are important habitats for freshwater biodiversity and ecosystems services, the strong but predictable species turnover and the opposing effects of environmental change on different trophic levels need to be embedded in conservation and management plans.

Soil life is highly diverse, and ecologically intricate due to myriad of biotic interactions that take place. Terrestrial nematodes have a high potential to serve as an effective and policy-relevant indicator group for ecosystem functioning and soil biodiversity. The work described in this thesis contributed to the robust mapping of nematode communities at scales relevant in both agronomic and environmental contexts. The overarching aim of the work described in this thesis was to contribute to a sound exploration of the potential of nematode communities as an indicator group for the biological condition of soils. Therefore, the distributions of a wide range of nematode taxa were studied, within and between trophic groups and in soils conditioned by various plant species and/or farming systems. In Chapter 2 nematode taxon-specific qPCR assays were used to pinpoint responses of nematode communities to invasive plant species Solidago gigantea in two invaded ecosystems: semi-natural grasslands and riparian floodplains. Nematode communities and fungal biomass were examined in adjacent invaded and uninvaded patches. The dominant presence of the invasive plant causes a decrease of plant species-richness and diversity, and an about twofold increase of fungal biomass. Only the density of a single group of fungivorous nematodes (Aphelenchoididea) increased, whereas the densities of two other, phylogenetically distinct lineages of fungivorous nematodes, Aphelenchidae and Diphtherophoridae, were unaffected by the local increase in fungal biomass. Apparently S. gigantea induces a local asymmetric boost of the fungal community, and only Aphelenchoididae were able to benefit from this change induced by the invasive plant. In Chapter 3 the outcome is shown of a test whether farming system effects are mirrored in compositional changes in nematode communities. The long-term impact of three farming systems (conventional, integrated and organic) on nematode communities was investigated

Currently, fungicides are necessary to protect potato crops against late blight, Phytophthora infestans, one of the world’s most damaging crop pathogens. The introgression of plant resistance genes from wild potato species targeted specifically to the late blight pathogen into susceptible potato varieties may alleviate the environmental impact of chemical control. Genetically modified plants are subject to an environmental risk assessment, and this includes testing for risks to the non-target arthropod community associated with the crop. The thesis begins with a review about the main plant defense responses and their role in influencing sequential interactions between herbivores and plant pathogens. The experimental chapters each focus on different aspects of the interaction between potato plants (both resistant and susceptible), the target pathogen (P. infestans) and several non-target insects. With each chapter, the scope widens: from the molecular gene expression in potato leaves in response to sequential attacks, to field scale biodiversity analyses. At the molecular level, one of the main findings was that the genomic position of the Rpi-vnt1 insertion conferring resistance to P. infestans influenced potato gene expression measured in leaves, when interacting with the non-target insect pests Myzus persicae (Green peach aphid) and Leptinotarsa decemlineata (Colorado potato beetle). Insect performance differed between the resistant GM and susceptible non-GM comparator. In the following chapter, the differences in insect performance were tested across a range of conventionally bred cultivars varying in resistance to P. infestans. Differences in M. persicae performance between several cultivars greatly outweighed the differences previously detected between the GM and non-GM comparator. These results are crucial in shaping the way risk is assessed in the context of GM crops, and these results are supported in our experiments assessing effects on biodiversity with pi

Objective. The feeding habits of Cocobolo (Andinoacara pulcher) in the cienaga Grande de Lorica, Sinu river basin, were studied. Materials and methods. The stomach content was analyzed using the Proportion of empty stomachs, Grade of digestion, Frequency of occurrence, numerical Frequency, Gravimetry, relative importance Index (RII) and the gut length-total length relationship. Results. 39.8% of stomachs were empty, 47.1% of preys were fresh and five food groups were identified. Vegetable remains was the most frequent group (63.8%) and the prey with greatest composition in weight (33.5%), while Rest of fishes was the most abundant group (34.7%). It was observed that in low and rising waters, fishes was the most consumed prey, while that in high and falling waters the most consumed prey was vegetable remains. Vegetable remains, detritus and fishes were food groups of secondary relative importance, while Insects and Others were circumstantial or incidental groups. Conclusions. The results achieved indicate that Cocobolo is a fish with omnivores feeding habits with a preference for vegetable remains., Objetivo. Se estudiaron los hábitos alimentarios de Cocobolo (Andinoacara pulcher) en la ciénaga Grande de Lorica, cuenca del río Sinú, Colombia. Materiales y Métodos. El contenido estomacal se evaluó con el Coeficiente de vacuidad, Grado de llenado, Grado de digestión, Frecuencia de ocurrencia, Frecuencia numérica, Gravimetría, Índice de importancia relativa y la relación longitud intestinal-longitud total. Resultados. El 39.8% de los estómagos se encontró vacío, el 47.1% de las presas en estado fresco y se identificaron cinco grupos alimentarios. Material vegetal fue el grupo más frecuente (63.8%) y con mayor composición por peso (33.5%), mientras que Restos de peces fue el más abundante (34.7%). Se observó que en aguas bajas y en aguas ascendentes, peces fue la presa más consumida, mientras que en aguas altas y aguas descendentes, fue material vegetal. Material vegetal, detritos y restos de peces fueron grupos alimentarios de importancia relativa secundaria, mientras que insectos y otros fueron circunstanciales o incidentales. Conclusiones. Los resultados alcanzados indican que Cocobolo es un pez de hábitos alimentarios omnívoros con preferencia por material vegetal.

Иако је и даље у употреби, термин „тешки метал“ различити аутори дефинишу на различите начине бројним параметрима. Извори загађења тешким металима могу бити природни, али су најчешће антропогени. Ова класа загађивача представља значајну претњу за животну средину и врсте које живе у њој, као и потенцијалну претњу за људско здравље. Најбитнија је опасност коју представљају токсични елементи – арсен, жива, кадмијум и олово. Осим токсичних елемената, и елементи у траговима, као и есенцијални микронутријенти, могу показивати токсична својства ако су присутни у великим концентрацијама. У овом раду анализиране су концентрације 18 елемената (Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Se, Sr, Zn) у ткивима 11 врста риба – Esox lucius (штука), Alburnus alburnus (укљева), Cyprinus carpio (шаран), Pelecus cultratus (сабљар), Silurus glanis (сом), Lota lota (манић), Gymnocephalus cernua (балавац), Perca fluviatilis (гргеч), Sander lucioperca (смуђ), Babka gymnotrachelus (главоч тркач) и Neogobius melanostomus (главоч округлак). Основни циљ био је да се установи да ли постоје сличности и/или разлике у биоакумулацији елемената у одређеним ткивима код различитих врста. Анализиране врсте су представници различитих трофичких нивоа, што има значајан утицај на биоконцентрацију у ткивима, а може указати и на биомагнификацију појединих елемената дуж трофичког ланца. Врсте су хватане у периоду између 2010. и 2012. године на два локалитета, између 1168. и 1170. речног километра Дунава у Београду. Ови локалитети су бирани због близине ушћа Саве (која доноси додатно загађење) у Дунав, близине урбаног дела Београда, као и близине пољопривредних површина. Анализа 18 елемената у ткивима риба урађена је помоћу индуктивно спрегнуте плазма- оптичке емисионе спектрометрије (ICP-OES). За одређивање старости јединки коришћене су крљушти, жбице пераја (сом) и отолити (манић)..., Although still in use, the term “heavy metal” is defined in different ways, based on a number of parameters, by different authors. Sources of heavy metal contamination can be natural, yet they are mostly anthropogenic. This class of pollutants poses a significant threat to environment and species living in it, as well as a potential threat to human health. The most significant threat are the toxic elements – arsenic, mercury, cadmium, and lead. Apart from these toxic elements, both trace elements and essential micronutrients can also show toxic properties if present in large concentrations. The concentrations of 18 elements (Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Se, Sr, Zn) in tissues of eleven fish species – Esox lucius (pike), Alburnus alburnus (common bleak), Cyprinus carpio (common carp), Pelecus cultratus (sichel), Silurus glanis (catfish), Lota lota (burbot), Gymnocephalus cernua (ruffe), Perca fluviatilis (perch), Sander lucioperca (pikeperch), Babka gymnotrachelus (racer goby), and Neogobius melanostomus (round goby), were analyzed in this study. The principal aim was to find out if there were any similarities and/or differences in element bioaccumulation in assorted tissues of different species. The analyzed species represent different trophic levels, which has a significant impact on bioconcentration in tissues, and it can as well as point to biomagnification of certain elements along the trophic chain. Species were caught between 2010 and 2012 on two locations, between 1168th and 1170th river kilometer of the Danube River in Belgrade. These locations were selected for their proximity to the confluence of the Sava River (who carries additional pollution) into the Danube, their proximity to the urban area of Belgrade, as well as their proximity to agricultural areas. The analysis of 18 elements in fish tissues was done using an inductively coupled plasma optical emission spectrometry (ICP-OES). For the determination of fish age, scales

cum laude graduation

Plants have evolved intriguing defences against insect herbivores. Compared to constitutive Plants have evolved intriguing defences against insect herbivores. Compared to constitutive defences that are always present, plants can respond with inducible defences when they are attacked. Insect herbivores can induce phenotypic changes in plants and consequently these changes may differentially affect subsequent attackers and their associated insect communities. Many studies consider herbivore-feeding damage as the first interaction between plants and insects. The originality of this study was to start with the first phase of herbivore attack, egg deposition, to understand the consequences of plant responses to eggs on subsequently feeding caterpillars and their natural enemies. The main plant species used for most of the experiments was Brassica nigra (black mustard), which occurs naturally in The Netherlands. The main herbivore used was the lepidopteran Pieris brassicae, which lays eggs in clusters and feeds on plants belonging to the Brassicaceae family. This study investigated plant-mediated responses to oviposition and their effects on different developmental stages of the herbivore, such as larvae and pupae. Furthermore, the effects of oviposition were extended to four more plant species of the same family, and to higher trophic levels including parasitoids and hyperparasitoids. The experiments were conducted under laboratory, semi-field and field conditions. This study shows that B. nigra plants recognize the eggs of P. brassicae and initiate resistance against subsequent developmental stages of the herbivore. Interestingly, plant responses to oviposition were found to be species specific. Plants did not respond to egg deposition by another herbivore species, the generalist moth Mamestra brassicae. Moreover, most of the Brassicaceae species tested were found to respond to P. brassicae eggs, which indicates that plant responses against oviposition are more common a

The EcoTroph modeling approach was applied to five Mediterranean marine ecosystems to characterize their food webs and investigate their responses to several simulated fishing scenarios. First, EcoTroph was used to synthesize the outputs of five pre-existing heterogeneous Ecopath models in a common framework, and thus to compare different ecosystems through their trophic spectra of biomass, catch, and fishing mortalities. This approach contributes to our understanding of ecosystem functioning, from both ecological and fisheries perspectives. Then, we assessed the sensitivity of each ecosystem to fishery, using EcoTroph simulations. For the five ecosystems considered, we simulated the effects of increasing or decreasing fishing mortalities on both the biomass and the catch per trophic class. Our results emphasize that the Mediterranean Sea is strongly affected by the depletion of high trophic level organisms. Results also show that fisheries impacts, at the trophic level scale, differ between ecosystems according to their trophic structure and exploitation patterns. A top-down compensation effect is observed in some simulations where a fishing-induced decrease in the biomass of predators impacts their prey, leading to an increase in the biomass at lower trophic levels. The results of this comparative analysis highlight that ecosystems where top-down controls are observed are less sensitive to variations in fishing mortality in terms of total ecosystem biomass. This suggests that the magnitude of top-down control present in a system can affect its stability. © 2015 Elsevier B.V.

Increasing biomasses of gelatinous zooplankton presumably have major implications for the structure and function of marine food webs at large; however, current data on lower trophic levels are scarce, as most studies have focused on the immediate effects on zooplankton and fish larvae only. We examined the short-term impact of larvae and adults of the invasive ctenophore Mnemiopsis leidyi on a summer planktonic food web in the estuarine southern Baltic Sea, with special emphasis on the microbial loop. Grazing by M. leidyi reduced the mesozooplankton biomass, followed by increased dinoflagellate biomass in treatments with M. leidyi. While chlorophyll a increased most in the treatments with M. leidyi, small phytoplankton and ciliates decreased in all treatments. M. leidyi had a slight effect on bacterial abundance, but not on bacterial production, ectoenzymatic activities, or community composition. Undetectable levels of phosphate and a gradual accumulation of dissolved organic carbon during the experiment suggested a malfunctioning microbial loop scenario. The experiment shows that direct and indirect short-term effects of M. leidyi on the estuarine food web are limited to higher trophic levels and indicates that top-down and bottom-up consequences of M. leidyi expansions on the microbial loop will likely depend on local nutrient conditions.

Bijdrage van Marcel Klaassen, Nederlands Instituut voor Ecologie, met de presentatie 'What's the role of birds in aquatic ecosystems and how may birds be affected by climate change?', op dag 1 van het symposium Climate changes and aquatic ecosystems, januari 2010, te Arnhem.

Quantifying deep-sea food webs can be resource intensive due to the difficulties of sampling fishes from the deep sea. The diet of fishes is often quantified through stomach content analysis, through this method has many sampling constraints, and it can be difficult to obtain sufficient samples for an in-depth study. This study attempts to fill a critical data gap by determining the diet and trophic level of the deep-sea Roughtail Skate, Bathyraja trachura, using traditional stomach content analysis. This study also attempts to determine the validity and accuracy of stable isotope analysis in the continental slope fishes of the deep-sea of the eastern North Pacific, as an alternative method to determine trophic level in fishes.The Roughtail Skate is an abundant deep-sea skate in the eastern North Pacific. Little is known about the diet of this skate, which is landed as by-catch in commercial bottom trawls. Skates were collected between 2005 and 2008 from fishery-independent trawl surveys of the continental slope and outer shelf. Geometric Index of Importance (GII) values indicated that crustaceans (71.4%), fishes (17.8%), polychaetes (4.3%), and cephalopods (3.7%) were the most important prey groups in the diet. Diet differed significantly with total length, but not with sex. Larger individuals (by total length) had significantly higher trophic level values, and year and latitude explained variation in the diet for three prey categories.In this study, fishes and invertebrates collected from the continental slope (1,000 m depth) of the eastern North Pacific were analyzed using stable isotope analysis (SIA). The carbon and nitrogen stable isotope results were used to construct dual isotope plots to investigate the trophic relationships of this deep-sea community. The plots indicated a decoupling of the benthic and pelagic food webs, with the benthic food web being isotopically enriched. Stomach and isotope samples were collected from 32 Roughtail Skates (Bathyraja tra

The Ponto-Caspian round goby (Neogobius melanostomus, Pallas 1814) most probably was established in the Gulf of GdaA""sk, Baltic Sea, in the late 1980's and has since become one of the dominant species in the region. In this study we assess the role of round gobies as prey for two important fish species in the Gulf of GdaA""sk, cod (Gadus morhua) and perch (Perca fluviatilis). We compared their present diet with stomach analyses from the area prior the round goby establishment, as well as with diet analysis from Baltic regions where round gobies are absent. There were large differences in the diet between cods from the Gulf of GdaA""sk 2003-2006 compared to cods in earlier studies (1977-1981) from the Southern Baltic Sea. There were also large differences in cod and perch diets from areas with and without round goby. Presently, round goby constitutes the most important prey for medium sized cods in Gulf of GdaA""sk, and perch from the same area almost exclusively feed on gobiids. Stomach analysis, trophic level estimates, and stable isotope analyses all indicated that cod and perch in Gulf of GdaA""sk after the round goby establishment belonged to a similar trophic level. Beside round goby, no mussel feeding fish contributed much to the diet of cod or at all to the diet of perch. Thus, it is likely that round gobies constitute a new energetic pathway from mussels to top predators. However, due to the short time elapsed after round goby establishment, we can only speculate on the species future impacts on Baltic food webs., authorCount :3

Quantifying deep-sea food webs can be resource intensive due to the difficulties of sampling fishes from the deep sea. The diet of fishes is often quantified through stomach content analysis, through this method has many sampling constraints, and it can be difficult to obtain sufficient samples for an in-depth study. This study attempts to fill a critical data gap by determining the diet and trophic level of the deep-sea Roughtail Skate, Bathyraja trachura, using traditional stomach content analysis. This study also attempts to determine the validity and accuracy of stable isotope analysis in the continental slope fishes of the deep-sea of the eastern North Pacific, as an alternative method to determine trophic level in fishes.The Roughtail Skate is an abundant deep-sea skate in the eastern North Pacific. Little is known about the diet of this skate, which is landed as by-catch in commercial bottom trawls. Skates were collected between 2005 and 2008 from fishery-independent trawl surveys of the continental slope and outer shelf. Geometric Index of Importance (GII) values indicated that crustaceans (71.4%), fishes (17.8%), polychaetes (4.3%), and cephalopods (3.7%) were the most important prey groups in the diet. Diet differed significantly with total length, but not with sex. Larger individuals (by total length) had significantly higher trophic level values, and year and latitude explained variation in the diet for three prey categories.In this study, fishes and invertebrates collected from the continental slope (1,000 m depth) of the eastern North Pacific were analyzed using stable isotope analysis (SIA). The carbon and nitrogen stable isotope results were used to construct dual isotope plots to investigate the trophic relationships of this deep-sea community. The plots indicated a decoupling of the benthic and pelagic food webs, with the benthic food web being isotopically enriched. Stomach and isotope samples were collected from 32 Roughtail Skates (Bathyraja tra

We propose to combine field observations and laboratory experiments to understand the coupling of physical and biological processes that transfer energy from lower to higher trophic levels on a small offshore bank. We focus this study on Platts Bank, in the western Gulf of Maine, and on the the relationship between internal waves, patchiness of planktonic organisms (especially euphausiids, Meganyctiphanes norvegica), and feeding and residence times of upper trophic level predators (marine and avian, but especially baleen whales, and particularly the humpback whale, Megaptera novaeangliae). Observations from Platts Bank and other feeding hotspots in the Gulf of Maine show that high levels of feeding activity are ephemeral--sometimes very active, often not. Differences can exist between weeks and between years. Our goals are to understand the factors that drive the "on" and "off" patterns of feeding at features such as Platts Bank, and to gain insights into the foraging strategies and mechanisms employed by highly mobile predators to exploit ephemeral and scattered feeding locations.

Het is bekend dat planten als verticale communicatiekanalen kunnen fungeren tussen onder-en bovengrondse plantetende insecten. Worteleters veroorzaken veranderingen in biomassa en de chemische samenstelling van de bovengrondse delen van een plant. Deze veranderingen kunnen de overleving, de groei en de ontwikkeling van bladeters beïnvloeden. In het promotieproject werd onderzocht of en hoe de wisselwerking tussen ruimtelijk gescheiden insecten beperkt is tot planteneters, dan wel uitgebreid kan worden naar hogere trofische niveaus zoals bijvoorbeeld parasitaire wespen, de natuurlijke vijanden van de plantenetende insecten. Tijdens de 20e Nederlandse Entomologendag (19 december 2008) is de eerste NEV dissertatieprijs uitgereikt aan dit proefschrift

Lakes at high latitudes represent a range of biotic complexity imposed by strong abiotic limitations that are differentially ameliorated by biogeographic factors between the northern and southern latitudes. However, the communities in these lakes are simpler than those typically found in more temperate environments and represent a range of declining biocomplexity as conditions approach the limits to life in these extreme environments. This includes the relative importance of keystone predators and higher trophic levels (e.g., fish and birds) as well as the benthic-pelagic coupling in structuring the food webs. This chapter uses examples and case studies to explore food web interactions between microbial and classic food webs, the importance of autochthonous versus allochthonous carbon, and the implications of a changing climate.

Lakes at high latitudes represent a range of biotic complexity imposed by strong abiotic limitations that are differentially ameliorated by biogeographic factors between the northern and southern latitudes. However, the communities in these lakes are simpler than those typically found in more temperate environments and represent a range of declining biocomplexity as conditions approach the limits to life in these extreme environments. This includes the relative importance of keystone predators and higher trophic levels (e.g., fish and birds) as well as the benthic-pelagic coupling in structuring the food webs. This chapter uses examples and case studies to explore food web interactions between microbial and classic food webs, the importance of autochthonous versus allochthonous carbon, and the implications of a changing climate.

The mechanisms through which trophic interactions between species are indirectly mediated by distant members in a food web have received increasing attention in the field of ecology of multitrophic interactions. Scarcely studied aspects include the effects of varying plant chemistry on herbivore immune defences against parasitoids. We investigated the effects of constitutive and herbivore-induced variation in the nutritional quality of wild and cultivated populations of cabbage (Brassica oleracea) on the ability of small cabbage white Pieris rapae (Lepidoptera, Pieridae) larvae to encapsulate eggs of the parasitoid Cotesia glomerata (Hymenoptera, Braconidae). Average encapsulation rates in caterpillars parasitised as first instars were low and did not differ among plant populations, with caterpillar weight positively correlating with the rates of encapsulation. When caterpillars were parasitised as second instar larvae, encapsulation of eggs increased. Caterpillars were larger on the cultivated Brussels sprouts plants and exhibited higher levels of encapsulation compared with caterpillars on plants of either of the wild cabbage populations. Observed differences in encapsulation rates between plant populations could not be explained exclusively by differences in host growth on the different Brassica populations. Previous herbivore damage resulted in a reduction in the larval weight of subsequent herbivores with a concomitant reduction in encapsulation responses on both Brussels sprouts and wild cabbage plants. To our knowledge this is the first study demonstrating that constitutive and herbivore-induced changes in plant chemistry act in concert, affecting the immune response of herbivores to parasitism. We argue that plant-mediated immune responses of herbivores may be important in the evaluation of fitness costs and benefits of herbivore diet on the third trophic level

Het is bekend dat planten als verticale communicatiekanalen kunnen fungeren tussen onder-en bovengrondse plantetende insecten. Worteleters veroorzaken veranderingen in biomassa en de chemische samenstelling van de bovengrondse delen van een plant. Deze veranderingen kunnen de overleving, de groei en de ontwikkeling van bladeters beïnvloeden. In het promotieproject werd onderzocht of en hoe de wisselwerking tussen ruimtelijk gescheiden insecten beperkt is tot planteneters, dan wel uitgebreid kan worden naar hogere trofische niveaus zoals bijvoorbeeld parasitaire wespen, de natuurlijke vijanden van de plantenetende insecten. Tijdens de 20e Nederlandse Entomologendag (19 december 2008) is de eerste NEV dissertatieprijs uitgereikt aan dit proefschrift

We propose to combine field observations and laboratory experiments to understand the coupling of physical and biological processes that transfer energy from lower to higher trophic levels on a small offshore bank. We focus this study on Platts Bank, in the western Gulf of Maine, and on the relationship between internal waves, patchiness of planktonic organisms (especially euphausiids, Meganyctiphanes norvegica), and feeding and residence times of upper trophic level predators (marine and avian, but especially baleen whales, and particularly the abundant humpback whales, Megaptera novaeangliae). Observations from Platts Bank and other feeding hotspots in the Gulf of Maine show that they are ephemeral - sometimes very active, often not. Our goals are to understand the factors that drive the "on" and "off" patterns of feeding at features such as Platts Bank, and to gain insights into the foraging strategies and mechanisms employed by highly mobile predators to exploit ephemeral and scattered feeding locations. 1. Quantify patterns of upper trophic level use of Platts Bank over multiple years, extending observations from the original two years of observation that preceded this award. 2. Describe behaviors adapted to feeding on Platts Bank and foraging on networks of scattered feeding sites such as Platts. 3. Measure and describe the internal wave field, associated velocities, and euphausiid distribution and abundance patterns. 4. Use field and laboratory studies to document and quantify the behavior of euphausiids and the coupled bio-physical processes that affect surface patch formation, in particular testing the hypothesis that internal waves help drive surface aggregations and upper trophic level feeding.

cum laude graduation (with distinction)

De resultaten van dit proefschrift laten zien dat het voor de bestrijding van bovengrondse plaaginsecten van groot belang is te weten welke ondergrondse insecten aanwezig zijn en wat er rond de wortel van de plant gebeurt, en vice versa. Zulke bovengrondse-ondergrondse interacties tussen insecten via veranderingen in de in de waardplant kunnen namelijk de efficiëntie van bestrijdingsprogramma's significant beïnvloeden

Through artificial selection, domesticated plants often contain modified levels of primary and secondary metabolites compared to their wild progenitors. It is hypothesized that the changed chemistry of cultivated plants will affect the performance of insects associated with these plants. In this paper, the development of several specialist and generalist herbivores and their endoparasitoids were compared when reared on a wild and cultivated population of cabbage, Brassica oleracea, and a recently established feral Brassica species. Irrespective of insect species or the degree of dietary specialization, herbivores and parasitoids developed most poorly on the wild population. For the specialists, plant population influenced only development time and adult body mass, whereas for the generalists, plant populations also affected egg-to-adult survival. Two parasitoid species, a generalist (Diadegma fenestrale) and a specialist (D. semiclausum), were reared from the same host (Plutella xylostella). Performance of D. semiclausum was closely linked to that of its host, whereas the correlation between survival of D. fenestrale and host performance was less clear. Plants in the Brassicaceae characteristically produce defense-related glucosinolates (GS). Levels of GS in leaves of undamaged plants were significantly higher in plants from the wild population than from the domesticated populations. Moreover, total GS concentrations increased significantly in wild plants after herbivory, but not in domesticated or feral plants. The results of this study reveal that a cabbage cultivar and plants from a wild cabbage population exhibit significant differences in quality in terms of their effects on the growth and development of insect herbivores and their natural enemies. Although cultivated plants have proved to be model systems in agroecology, we argue that some caution should be applied to evolutionary explanations derived from studies on domesticated plants, unless some knowledge

De resultaten van dit proefschrift laten zien dat het voor de bestrijding van bovengrondse plaaginsecten van groot belang is te weten welke ondergrondse insecten aanwezig zijn en wat er rond de wortel van de plant gebeurt, en vice versa. Zulke bovengrondse-ondergrondse interacties tussen insecten via veranderingen in de in de waardplant kunnen namelijk de efficiëntie van bestrijdingsprogramma's significant beïnvloeden

Fisheries catches represent a net export of mass and energy that can no longer be used by trophic levels higher than those fished. Thus, exploitation implies a depletion of secondary production of higher trophic levels (here the production of mass and energy by herbivores and carnivores in the ecosystem) due to the removal of prey. The depletion of secondary production due to the export of biomass and energy through catches was recently formulated as a proxy for evaluating the ecosystem impacts of fishing–i.e., the level of ecosystem overfishing. Here we evaluate the historical and current risk of ecosystem overfishing at a global scale by quantifying the depletion of secondary production using the best available fisheries and ecological data (i.e., catch and primary production). Our results highlight an increasing trend in the number of unsustainable fisheries (i.e., an increase in the risk of ecosystem overfishing) from the 1950s to the 2000s, and illustrate the worldwide geographic expansion of overfishing. These results enable to assess when and where fishing became unsustainable at the ecosystem level. At present, total catch per capita from Large Marine Ecosystems is at least twice the value estimated to ensure fishing at moderate sustainable levels

It is widely reported that plants emit volatile compounds when they are attacked by herbivorous insects, which may be used by parasitoids and predators to locate their host or prey. The study of herbivore-induced plant volatiles and their role in mediating interactions between plants, herbivores and their natural enemies have been primarily based on aboveground systems, generally ignoring the potential interactions between above and belowground infochemical- and food webs. This study examines whether herbivory by Delia radicum feeding on roots of Brassica nigra (black mustard) affects the behaviour of Cotesia glomerata, a parasitoid of the leaf herbivore Pieris brassicae, mediated by changes in plant volatiles. In a semi-field experiment with root-damaged and root-undamaged plants C. glomerata prefers to oviposit in hosts feeding on root-undamaged plants. In addition, in a flight-cage experiment the parasitoid also prefers to search for hosts on plants without root herbivores. Plants exposed to root herbivory were shown to emit a volatile blend characterized by high levels of specific sulphur volatile compounds, which are reported to be highly toxic for insects, combined with low levels of several compounds, i.e. beta-farnesene, reported to act as attractants for herbivorous and carnivorous insects. Our results provide evidence that the foraging behaviour of a parasitoid of an aboveground herbivore can be influenced by belowground herbivores through changes in the plant volatile blend. Such indirect interactions may have profound consequences for the evolution of host selection behaviour in parasitoids, and may play an important role in the structuring and functioning of communities.

Herbivory can induce changes in plant growth, physiology, morphology, and phenology. Such herbivore-induced changes by insects are commonly observed in many plant species. Changes in the host plant can alter interaction linkages between plants, herbivores and higher trophic levels such as carnivores of the herbivores. These interaction linkages shape community organization and biodiversity in plant-based terrestrial communities. Considering that plants have both aboveground and belowground parts, systemic herbivore-induced changes within the plant could potentially link spatially separated herbivores associated with plants in the soil and in the aboveground (sub) system. Relatively recently, an increasing number of studies have shown that root herbivores, among other soil dwelling organisms, can indeed interact with foliar herbivores. Root herbivores change the quality and biomass of aboveground plant parts, which in turn influences the growth, development and survival of foliar herbivores. Similarly, foliar-feeding insects have been shown to influence root-feeding insects. This thesis explores whether, and mechanistically how, these feed-backs between root and foliar herbivores are transmitted through the soil and the aboveground food chains influencing the performance and behaviour of higher trophic levels. In Chapter 1, I introduce plant-insect interactions in a multitrophic context, briefly describing how the plant mediates these intricate interactions, and I describe the general aim and the outline of the thesis. In Chapter 2 I study the effects of root herbivores, at different densities, on the biomass and quality of the plant shoot, and on the performance of a foliar herbivore, its primary parasitoid and its secondary parasitoid (hyperparasitoid) sharing the host plant. In Chapter 3 I study the reverse effect; the effects of foliar herbivores on a root herbivore and its parasitoid mediated by the host plant. The results of these Chapters show that the spatial

The Marine Trophic Index (MTI) is proposed by the CBD as an indicator for sustainable fisheries and ecosystem integrity. This report explores the usefulness of the Marine Trophic Index (MTI) as an indicator for sustainable fisheries and ecosystem integrity for the Dutch situation

The majority of studies exploring interactions between above- and below-ground biota have been focused on the effects of root-associated organisms on foliar herbivorous insects. This study examined the effects of foliar herbivory by Pieris brassicae L. (Lepidoptera: Pieridae) on the performance of the root herbivore Delia radicum L. (Diptera: Anthomyiidae) and its parasitoid Trybliographa rapae (Westwood) (Hymenoptera: Figitidae), mediated through a shared host plant Brassica nigra L. (Brassicaceae). In the presence of foliar herbivory, the survival of D. radicum and T. rapae decreased significantly by more than 50%. In addition, newly emerged adults of both root herbivores and parasitoids were significantly smaller on plants that had been exposed to foliar herbivory than on control plants. To determine what factor(s) may have accounted for the observed results, we examined the effects of foliar herbivory on root quantity and quality. No significant differences in root biomass were found between plants with and without shoot herbivore damage. Moreover, concentrations of nitrogen in root tissues were also unaffected by shoot damage by P. brassicae larvae. However, higher levels of indole glucosinolates were measured in roots of plants exposed to foliar herbivory, suggesting that the development of the root herbivore and its parasitoid may be, at least partly, negatively affected by increased levels of these allelochemicals in root tissues. Our results show that foliar herbivores can affect the development not only of root-feeding insects but also their natural enemies. We argue that such indirect interactions between above- and below-ground biota may play an important role in the structuring and functioning of communities.

Keywords: vegetational diversity, intercropping, plant quality, herbivores, D. semiclausum, foraging behaviour, time-allocationReduction of herbivore populations is more often observed in vegetationally diverse than in simple ecosystems. Consequently, plant-species mixtures (i.e. intercropping) may be used to manage pest problems in agro-ecosystems, thereby contributing to the development of ecologically sustainable crop production. Compared with monotypic stands, increasing vegetation diversity may suppress herbivore populations through the reduction in the apparency and quality of crop plants and by the increased success of natural enemies. Unfortunately, the highly variable responses of both herbivores and natural enemies to intercropping provide insufficient information to make generalisations for the selection of pest-suppressive plant-mixtures. An explanation for this lack of information is that predictions of the hypotheses explaining the pest-suppression are relevant at the population level, while the underlying mechanisms at the behavioural (i.e. functional) level remain largely untested. In this thesis I attempted to further our understanding of how vegetation diversity leads to pest suppression in agro-ecosystems. The aims were (1) to understand the cause(s) of lower herbivore numbers in vegetationally more diverse cropping systems compared to monocultures and (2) to study the behavioural bases of the responses of natural enemies to vegetation diversity. The studied system includedBrusselssprout ( Brassica oleracea gemmifera), its herbivores, and Diadegma semiclausum , a parasitoid of the diamondback moth. Vegetational diversity was characterised by mixingBrusselssprout with either barley ( Hordeum vulgare ) or mustard ( Sinapisalba ). Numbers of several herbivore species were reduced when Brussels sprout was mixed with barley. A study showed that the plant competition in the species mixture influenced herbivore responses by altering plant quality compare

Stemborers are major pests of maize and sorghum in tropical Africa. Various management approaches to stemborer control are being sought with emphasis on those that are environmentally sound, sustainable and economically feasible. Studies reported in this thesis were conducted to explore the potential of employing habitat management techniques to enhance the effectiveness of stemborer parasitoids. Emphasis was placed on the chemical and behavioural ecology of stemborer parasitoids in a diversified system that consisted of the stemborer host plants, maize and sorghum, stemborers and a non-host plant, molasses grass ( Melinis minutiflora ).Olfactometric studies on the stimuli involved in long-range foraging behaviour of the parasitoids Cotesia sesamiae and Dentichasmias busseolae revealed that host plant volatiles play a major role in guiding searching parasitoids to habitats that harbour their hosts. Volatiles from herbivore-injured plants were the most attractive. Sorghum was more attractive to the parasitoids than maize. Molasses grass volatiles were attractive to C. sesamiae but repellent to D. busseolae . Combining host plants and molasses grass did not have an additive effect of increasing the response of the parasitoids. Local growth conditions influenced the volatile blend produced by molasses grass grown in two different locations in Kenya, Thika and Mbita. This was manifested by their differential attractiveness to C. sesamiae . Dentichasmias busseolae did not discriminate between host species at a distance based on the volatiles released by infested host plants. Headspace analyses of volatiles emitted by uninfested and infested host plants and molasses grass grown at Thika and Mbita, revealed qualitative differences in their compositions. Infested host plants released a richer volatile blend than the uninfested host plants. Most of the compounds identified in the herbivore-injured plants were previously reported to play a role in parasitoid recruitment. Mola

Mesotrofe trilveentjes in Het Hol dreigen sterk aan biologische waarde in te boeten als gevolg van voortschrijdende verzuring en verlanding. Een van de maatregelen, het graven van een aantal greppels, is bemonsterd op sieralgen

Temidden van vele algen in het natuurreservaat bij Kortenhoef, bevonden zich enkele moeilijk te determineren soorten. Een analyse hiervan wordt gegeven

Many insect species use an aggregation pheromone to form groups with conspecifics in certain localities of the environment. This type of behaviour has a variety of implications for ecological interactions, both directly through the effect of the pheromone on the behaviour of con- and heterospecifics, and indirectly through the consequential aggregative distributions that may affect species interactions. The evolutionary ecology of the use of aggregation pheromone has received only little attention. Yet, these pheromones may play an intricate role in food web interactions by providing an accompanying information web.The aim of this thesis is to further our understanding on the ecological and evolutionary aspects of the use of aggregation pheromone in insects. By unravelling costs and benefits that arise from the use of aggregation pheromone in our ecological model organism, Drosophila melanogaster , we strive to answer why they use an aggregation pheromone and elucidate the ecological consequences of an aggregation pheromone in a food web context.In laboratory and field studies, we identified behaviours and interactions of the fruit fly D. melanogaster that were affected by its aggregation pheromone. The pheromone affected the distribution of adults, their eggs, competitor species and parasitoids. Moreover, a number of costs and benefits to the use of aggregation pheromone were indicated. In subsequent studies, the major hypotheses on costs and benefits were examined.A major benefit of using aggregation pheromone was shown to be aggregated oviposition. Aggregated oviposition enhanced the quality of the larval resource, as indicated by a higher survival of the larvae and larger size of the emerging flies. This Allee effect was characterised by a positive effect of adult density on larval fitness components, and may have arisen from the interaction between adult flies and micro-organisms (yeasts and fungi). Fungi antagonise yeast and larval development, while adults ca

This thesis describes research on multitrophic interactions between parasitoids, herbivores and plants. These are all involved in a dynamic game of hide-and-seek. Insect herbivores may occur in different spatial distributions across plants. Some species occur in local clusters, while others have a more even distribution. Parasitoids are challenged to deal effectively with such variation in the spatial distribution of their victims. I studied how different species and strains of Cotesia parasitoids make use of chemical information and foraging experience under varying spatial distributions of hosts.The parasitoids Cotesia glomerata and Cotesia rubecula show clear interspecific variation in foraging decisions when exploiting patches with herbivores. C. glomerata tunes its foraging decisions to the current environment as it gains experience with hosts during subsequent patch visits. In contrast, foraging decisions in C. rubecula seem insensitive to acquired experience. These Cotesia species prefer different herbivore species, that occur in different spatial distributions across plants. C. glomerata prefers to attack Pieris brassicae , that occurs in rare clusters of highly variable density. The parasitoid C. rubecula specialises on Pieris rapae that mostly feeds solitarily on plants. This leads the parasitoid C. glomerata to experience a more variable environment, with a wider scope for increased efficiency through learning.Both Pieris species are present in Europe, but the clustered host is absent in North America. The parasitoid C. glomerata was introduced to North America in 1883 to control solitarily feeding Pieris rapae , and about 350 generations of C. glomerata parasitoids have now foraged there. The experimental results suggest that American C. glomerata have adapted to forage for solitary host larvae, mostly through a loss of costly traits for finding rare clustered larvae. The European parasitoids spend a lot of time on explorative flights, while their Americ

During 2 deep-sea oceanographic cruises carried out in October 1996 and May 1998, megafauna (fish and decapod crustaceans), suprabenthos, zooplankton, and environmental variables from the water column (fluorescence and light transmission) were simultaneously collected between 210 and 1752 m depth. Fish were the dominant megafaunal taxon in biomass along the slope; decapod crustaceans were co-dominants at intermediate depths (between 402 and 710 m). Suprabenthos and zooplankton attained their maximal biomass at intermediate depths, with deeper maxima detected for suprabenthos (between 802 and 1322 m) than for zooplankton (between 402 and 802 m). Fish and decapod biomass were weakly correlated with each other, and with the suprabenthos-zooplankton biomass, fluorescence and light transmission. Significant correlations were, however, detected between the suprabenthos and zooplankton and their possible food-sources deduced from fluorometer and light transmission data, with different patterns depending on the distribution of each compartment (trophic level) in the water column and the sediment-water interface. Within a single taxon (crustaceans), size distribution for suprabenthos-zooplankton and megafaunal species followed opposite temporal patterns in our study. Among suprabenthos-zooplankton species, smaller specimens (recruitment) were detected in October 1996, coinciding with the highest fluorometer signals in the water column. The dominant phytoplankton/phytodetritus consumers (the euphausiid Euphausia krohni and the mysid Boreomysis arctica) showed clearer recruitment peaks during October than those species preying upon meiofaunal taxa (the amphipod Rhachotropis caeca, and the isopod Munnopsurus atlanticus). These results suggest that the influence of food input signals progressively decreases with increasing trophic level, and therefore the indirect effect of superficial production on top trophic levels is difficult to establish at least for the short time scales

The life-histories and the secondary production of four dominant peracarid crustaceans (the mysids Boreomysis arctica and Parapseudomma calloplura, the amphipod Rhachotropis caeca, and the isopod Ilyarachna longicornis) in bathyal depths of the Bay of Biscay (NE Atlantic; between 383 and 420 m) and the Catalan Sea (Northwestern Mediterranean; between 389 and 1355 m) were established. Both the Atlantic and the Mediterranean populations of the major part of the target-species had two generations/year with mean cohort-production intervals (CPI) ranging from 5.5 mo for Ilyarachna longicornis to 6.3 mo for Parapseudomma calloplura. The Hynes method showed secondary production to vary in the Bay of Biscay between 0.113 mg DW m−2 yr−1 for I. longirostris and 3.069 mg DW m−2 yr−1 for P. calloplura, with P/B ratios between 4.57 (I. longirostris) and 7.93 (Boreomysis arctica). In the Catalan Sea, production varied between 0.286 mg DW m−2 yr−1 for I. longirostris and 1.096 mg DW m−2 yr−1 for P. calloplura, with P/B between 5.72 (I. longirostris) and 6.66 (P. calloplura). Application of two different empiric models to the whole peracarid assemblage gave similar levels of secondary production in both study areas (between 29.26 and 32.14 mgDWm−2 yr−1 in the Bay of Biscay; between 26.23 and 26.54 mg DW m−2 yr−1 in the Catalan Sea). From the analysis of gut contents of 22 species the dominant species in each study area were assigned to two basic trophic levels, detritus feeders and predators. Also, cumulative curves of dominance showed high diversity (low dominance) for peracarid assemblages distributed at mid-bathyal depths (524–693 m) both in the Bay of Biscay off Arcachon and in the Catalan Sea off Barcelona. We also discuss and compare, both within and between areas, how environmental features may explain the observed diversity patterns, the trophic structure, and the production results obtained for the suprabenthos assemblages

Op grond van het voorkomen van sieralg-soorten (Desmidiaceae) werd voor negen wateren een oecologische evaluatie uitgevoerd (zuurgraad; voedselrijkdom) en de natuurwaarde bepaald op grond van de criteria diversiteit, zeldzaamheid en signaalwaarde

Barnacles are known to accumulate Zn to a phenomenal concentration, but physiological processes governing Zn accumulation are poorly defined. We determined the assimilation efficiency and efflux rate constant of Zn in barnacles (Balanus amphitrite) using radiotracer technique. Assimilation efficiency of Zn from ingested food ranged between 76 and 87\% for the diatom diets and between 86 and 98\% for the zooplankton preys. These AEs were the highest measured among aquatic invertebrates. Varying distribution in the soft tissues of zooplankton did not account for the variability of Zn AE observed among different zooplankton preys. Most Zn was distributed in the guts of the animals, presumably associated with the numerous granules beneath the gut epithelium. The efflux rate constant was 0.003 d(-1), and the calculated biological retention halftime was about 230 days. Using a simple bioenergetic-based kinetic model, we demonstrated that trophic transfer can account for such a high Zn concentration in barnacles. The predicted Zn concentrations in barnacles (2610-11 560 mu g g(-1))were directly comparable to the concentrations measured in Hong Kong coastal waters (3100-11 000 mu g g(-1)) The high Zn concentration is related to its very efficient assimilation in barnacles coupled with a very low efflux rate. Biological variability must be fully appreciated before barnacles can be designated as an appropriate biomonitor of Zn contamination in coastal waters. Our study suggests that metal concentration in aquatic animals can be predicted only when both physiological and geochemical processes are considered.