Matrix composition and patch edges influence plant-herbivore interactions in marine landscapes

38 páginas, 4 figuras, 3 tablas.1. The functioning of ecosystems can be strongly driven by landscape attributes. Despite its importance, however, our understanding of how landscape influences ecosystem function derives mostly from species richness and abundance patterns, with few studies assessing how these relate to actual functional rates. 2. We examined the influence of landscape attributes on the rates of herbivory in seagrass meadows, where herbivory has been identified as a key process structuring these relatively simple systems. The study was conducted in three representative Posidonia oceanica meadows. The principal herbivores in these meadows are the fish Sarpa salpa and the sea urchin Paracentrotus lividus, and we hypothesised that differences in their interaction with landscape attributes would significantly influence herbivory rates. 3. We measured herbivore abundance, herbivory rates, primary production and plant quality (C:N) in seagrass patches embedded either in rock or in sand (matrix attribute), in patches either near or far from a rocky reef (distance attribute) and at the edges and interior of meadows. 4. Our results show that matrix and meadow edges significantly affected the actual levels of herbivory. Herbivory rates were higher in seagrass patches embedded in a rocky matrix compared to those on sand, and herbivory at the centre of seagrass meadows was higher than at the edges. In contrast, patch distance to rocky reefs did not affect herbivory. Neither herbivore abundance nor food quality explained the patterns across different landscape attributes. This suggests that variation in herbivory across the landscape may be related much more to behavioural differences between species in their evaluation of risk, movement, and food preference in relation to the landscape structure. 5. Our results indicate that richness and abundance patterns may mask critical interactions between landscape attributes and species responses, which result in considerable heterogeneity in the way key functional processes like herbivory are distributed across the ecosystem mosaic.The Spanish Ministry of Science and Innovation funded this research (projects CTM2010-22273-C02-01 and 02). The Spanish Ministry of Education supported JP (scholarship AP2008-01601) and the Spanish National Research Council supported AG (scholarship JAEPre_08_00466).Peer reviewe

Matrix composition and patch edges influence plant-herbivore interactions in marine landscapes

38 páginas, 4 figuras, 3 tablas.1. The functioning of ecosystems can be strongly driven by landscape attributes. Despite its importance, however, our understanding of how landscape influences ecosystem function derives mostly from species richness and abundance patterns, with few studies assessing how these relate to actual functional rates. 2. We examined the influence of landscape attributes on the rates of herbivory in seagrass meadows, where herbivory has been identified as a key process structuring these relatively simple systems. The study was conducted in three representative Posidonia oceanica meadows. The principal herbivores in these meadows are the fish Sarpa salpa and the sea urchin Paracentrotus lividus, and we hypothesised that differences in their interaction with landscape attributes would significantly influence herbivory rates. 3. We measured herbivore abundance, herbivory rates, primary production and plant quality (C:N) in seagrass patches embedded either in rock or in sand (matrix attribute), in patches either near or far from a rocky reef (distance attribute) and at the edges and interior of meadows. 4. Our results show that matrix and meadow edges significantly affected the actual levels of herbivory. Herbivory rates were higher in seagrass patches embedded in a rocky matrix compared to those on sand, and herbivory at the centre of seagrass meadows was higher than at the edges. In contrast, patch distance to rocky reefs did not affect herbivory. Neither herbivore abundance nor food quality explained the patterns across different landscape attributes. This suggests that variation in herbivory across the landscape may be related much more to behavioural differences between species in their evaluation of risk, movement, and food preference in relation to the landscape structure. 5. Our results indicate that richness and abundance patterns may mask critical interactions between landscape attributes and species responses, which result in considerable heterogeneity in the way key functional processes like herbivory are distributed across the ecosystem mosaic.The Spanish Ministry of Science and Innovation funded this research (projects CTM2010-22273-C02-01 and 02). The Spanish Ministry of Education supported JP (scholarship AP2008-01601) and the Spanish National Research Council supported AG (scholarship JAEPre_08_00466).Peer reviewe

Penicillium aureocephalum Munt.-Cvetk., Hoyo et Gómez-Bolea, un interessant ascomicet anamòrfic amb aspecte de mixomicet : distribució, ecologia i fenologia

Cinc anys després de la descripció de Penicillium aureocephalum per Muntañola-Cvetkovic, Hoyo i GórnezBolea, els autors del present treball han anat afegint Inés dades de camp a les ja existents, que comencen a subministrar una imatge més viva d'aquest curiós anamorf saprotrófic dins de les comunitats naturals on esporula. El present treball és un resum d'aquestes dades corológiques, ecológiques i fenológiques, acompanyat de comentaris. La principal conclu sió és que I'espécie se' ns presenta com un fong termófil que colonit za preferentm ent fulles caigudes de surera (Quercus suber), que han mort a l' arbre per la calor produída per incendis, pero que també pot créixer, menys sovint, sobre altres substrats, com ara fulles o fruits de Cistus salviifolius, C. ladanifer, Quercus coccifera, etc. que han estat descarre gats per les plantes com a resposta a un fort estrés hídric. El treball inclou un mapa de la distribuci ó de I'espécie en el Pare Natural del Cap de Creus, fins ara I' área óptima de creixement, i un altre mapa amb la distribució coneguda actualment en els Paisos Catalans, on apareix provisionahnent endémica. S'ofereix un estudi macrofotográfic de l'especie, útil per ajudar els mic ólegs a trobar noves localitat s d'aquest curiosa especie d'anamorf, tan diferent de les més conegudes de Penicillium , ja que té aspect e de mixomic et, que es comporta COIll a term ófila i saprotrófica sobre fulles riques en nutrients.Five years after the description of Penicillium aureocephalum by Muntañola-C vetkovic, Hoyo and G ómez-Bolea, an increasing wealth of field data has been gathered by the authors, which provide a vivid image of the anamorph of this curious saprotrophic species. Chorological, ecological and phenological data are here summarized and discussed. The species appears to be thermophilou s, preferentially colonizing fallen leaves of cork trees (Quercus suber) killed by wildfires, but also growing sometimes on other substrata, such as dead leaves of Cistus salviifolius,C. ladanifer, Quercus coccifera, etc. which may have dropped as a response to severe water stress. A distribution map of the species in the Natural Park of Cap de Creus, which apparently is its natural habitat and another nowith showing the currently known distribution in the Catalan Countries, are given. A macrophotographic survey ofthe species is also included in order to aid in the recognition of this curious myxomycete-looking thermophilou s, anamorphic species, saprotrophic on nutrient-rich substrata, and so different from the usual Penicillium taxa

Immanent conditions determine imminent collapses: nutrient regimes define the resilience of macroalgal communities

Este artículo contiene 9 páginas, 5 figuras.Predicting where state-changing thresholds lie can be inherently complex in ecosystems characterized by nonlinear dynamics. Unpacking the mechanisms underlying these transitions can help considerably reduce this unpredictability. We used empirical observations, field and laboratory experiments, and mathematical models to examine how differences in nutrient regimes mediate the capacity of macrophyte communities to sustain sea urchin grazing. In relatively nutrient-rich conditions, macrophyte systems were more resilient to grazing, shifting to barrens beyond 1 800 g m22 (urchin biomass), more than twice the threshold of nutrient-poor conditions. The mechanisms driving these differences are linked to how nutrients mediate urchin foraging and algal growth: controlled experiments showed that low-nutrient regimes trigger compensatory feeding and reduce plant growth, mechanisms supported by our consumer–resource model. These mechanisms act together to halve macrophyte community resilience. Our study demonstrates that by mediating the underlying drivers, inherent conditions can strongly influence the buffer capacity of nonlinear systems.The Spanish Ministry of Science and Innovation funded this research (projects CMT2010-22273-C02-01-02 and CMT2013- 48027-C03-R) and supported J.B. (scholarship BES-2011-043630) and D.A. (Ramon y Cajal fellowship). The Spanish National Research Council supported R.A.’s visitorship (CSIC-201330E062).Peer reviewe

Forgotten landscapes: public attitudes and perceptions of coastal saltmarshes

As the field of public perceptions research continues to grow alongside an increasing recognition of the importance of understanding the complex interactions between society and the natural environment, this needs to consider all types of ecosystem, habitat and species. Although interest in public perceptions towards the global seas and coasts is increasing, the field is dominated by research focused on charismatic environments and species (e.g. coral reefs or marine mammals), and specific activities or human interactions with the seas and/or coasts (e.g. beach use, marine renewable energy). Whilst there has been some research on beaches and sand dunes, this is the first discrete piece of research which evaluates public views on the less ‘attractive’ coastal fringe environments, such as saltmarshes or mudflats, particularly in temperate regions. This paper presents the findings of a national survey (n = 1136) that aimed to understand public awareness and attitudes towards Welsh saltmarshes, and the ecosystem services and benefits derived from such systems. Through the questionnaire, we found limited public awareness, and a high amount of uncertainty, associated with saltmarshes and their societal benefits, indicating a need to foster and enhance current levels of public knowledge and understanding of saltmarshes, and their role within the wider coastal landscape. The influence of a range of respondent characteristics on perceptions. Given the position of salt marshes at the land-sea interface, the myriad of socio-ecological interactions they experience, and ongoing efforts to develop effective complementary marine and land-based planning and management, it is increasingly apparent that understanding public perceptions towards saltmarshes is crucial. This study contributes to the evidence base of public attitudes for the more commonly under-valued coastal fringe environments, such as saltmarshes

Indirect grazing-induced mechanisms contribute to the resilience of Mediterranean seagrass meadows to sea urchin herbivory

Plant–herbivore interactions are often regulated by a series of direct and indirect buffer mechanisms (compensatory or defensive plant responses, population control, alternative resources) that can determine the relative stability of the system. In plant-dominated marine environments, these mechanisms are particularly important given how vulnerable these systems are to strong consumer pressure. Here, we evaluate the presence and, where possible, the strength, of five mechanisms that get activated under high herbivory pressure and are capable of dampening their effects in a seagrass meadow ecosystem: 1) seagrass compensatory growth, 2) increase in plant resistance, 3) availability of alternative resources, 4) predatory control and 5) density-dependent control. We assessed these mechanisms for the interaction between the Mediterranean seagrass Posidonia oceanica and the sea urchin Paracentrotus lividus through a short-term series of controlled field and laboratory experiments after simulated or natural herbivory events. Of the five mechanisms tested, we found that three mechanisms – availability of alternative resources, increased predation rate and reduction in sea urchin numbers – effectively dampened herbivory and worked as potential buffering mechanisms. In contrast, plant compensatory growth and resistance did not show clear responses. While compensatory growth and plant resistance are direct plant mechanism to tolerate the effects of herbivory, the rest are indirect mechanisms that begin with a modification of a plant trait (i.e. canopy height) that influences other species preference and/or behaviour, which in turn influences plant consumption. These adaptive behaviours may be a crucial and often overlooked factor in the remarkable resilience that Mediterranean seagrass ecosystems show to herbivory

A framework linking ecosystem services and human well‐being: Saltmarsh as a case study

1. The ecosystem services approach is based on the interdependencies between nature and human well‐being. However, while the ecosystem services aspect of this approach is well‐developed, the human well‐being aspect remains unstructured and vaguely defined. 2. An integrated conceptual framework was developed by adapting and linking the UK National Ecosystem Assessment‐Follow On framework with human well‐being domains. 3. As well as benefits, the notion of disbenefits was incorporated to recognise the potentially detrimental effects from interacting with nature. Benefits and disbenefits occur at the social–ecological interface and are classified by the seven domains of human well‐being they affect. 4. The framework is applied to saltmarsh habitat as a case study, highlighting knowledge gaps and the potential applicability and usefulness of the framework. In saltmarsh, benefits mainly accrue at larger scales with a greater impact affecting local to global individuals, while disbenefits tend to occur at a smaller scale and impact in‐situ individuals. 5. The framework provides in‐depth insight into links, trade‐offs and dichotomies between benefits and disbenefits and human well‐being, and improves accessibility to the complex research area of human well‐being. 6. This research can be a useful tool to guide environmental and health policy and management, as well as stakeholder engagement

Evaluating the extent and impact of the extreme Storm Gloria on Posidonia oceanica seagrass meadows

Extreme storms can trigger abrupt and often lasting changes in ecosystems by affecting foundational (habitat-forming) species. While the frequency and intensity of extreme events are projected to increase under climate change, its impacts on seagrass ecosystems remain poorly documented. In January 2020, the Spanish Mediterranean coast was hit by Storm Gloria, one of the most devastating recent climate events in terms of intensity and duration. We conducted rapid surveys of 42 Posidonia oceanica meadows across the region to evaluate the extent and type of impact (burial, unburial and uprooting). We investigated the significance of oceanographic (wave impact model), geomorphological (latitude, depth, exposure), and structural (patchiness) factors in predicting impact extent and intensity. The predominant impact of Storm Gloria was shoot unburial. More than half of the surveyed sites revealed recent unburial, with up to 40 cm of sediment removed, affecting over 50 % of the meadow. Burial, although less extensive, was still significant, with 10–80 % of meadow cover being buried under 7 cm of sediment, which is considered a survival threshold for P. oceanica. In addition, we observed evident signs of recently dead matte in some meadows and large amounts of detached drifting shoots on the sea bottom or accumulated as debris on the beaches. Crucially, exposed and patchy meadows were much more vulnerable to the overall impact than sheltered or continuous meadows. Given how slow P. oceanica is able to recover after disturbances, we state that it could take from decades to centuries for it to recoup its losses. Seagrass ecosystems play a vital role as coastal ecological infrastructure. Protecting vulnerable meadows from anthropogenic fragmentation is crucial for ensuring the resilience of these ecosystems in the face of the climate crisis.This study was funded by the CSIC project “Effects of storm Gloria on the western Mediterranean meadows (202030E052) and “Storms of change: as phenomena extreme weather alters Mediterranean coastal ecosystems, their services and their perception by society" (PID2020-113745RB-I00), state program of I+D+I Oriented to the Challenges of the Society and within the framework of the activities of the Spanish Government through the "Maria de Maeztu Centre of Excellence” accreditation to IMEDEA (CSIC-UIB) (CEX2021-001198). We want to thank the SPAS (Society of Fishing and Underwater Activities of Mataró) and the Mataró City Council, which has financed 25 years of the Alguer de Mataró project

Els grans temporals de mar: aliats i enemics de les plantes marines

Peer reviewe

Combined effects of fragmentation and herbivory on Posidonia oceanica seagrass ecosystems

9 páginas,3 figuras, 1 tabla.1. Fragmentation is a major agent for seagrass meadow decline, yet little is known about how it interacts with processes like herbivory, an important functional driver of seagrass meadows. The interaction with external stressors like fragmentation could exacerbate the effects of internal ecosystem drivers like herbivory, with distinct implications for ecosystem management. 2. We used manipulative field experiments to assess these interactive effects in two Posidonia oceanica seagrass meadows. We monitored replicated plots in small and large patches in two meadows suffering fragmentation with and without herbivores (using exclusion cages) to test whether fragment size and herbivory could act together to alter ecosystem functioning. We measured changes in defoliation rates, primary production, canopy height and nutrient content in all plots after 4 months of herbivore exclusion. 3. Our results show that herbivores increased defoliation rates resulting in reduced primary production, nutrient content and canopy structure (canopy height). Patch size (fragment) on its own also reduced primary production, nutrient content and canopy structure. We also observed significant additive interactions between herbivores and fragmentation on canopy structure and production responses. In addition, small patches showed nutrient limitation but were able to accumulate more carbohydrate reserves, probably due to a higher light availability. This may explain why small patches can persist under significant herbivore pressure. 4. Synthesis. While fragmentation has already been identified as an important external agent of seagrass decline, the combination of fragmentation and herbivory can seriously exacerbate structural losses and affect primary production, profoundly compromising the role of seagrasses as habitatforming ecosystems. These interactions between external stressors and internal drivers may result in large unexpected consequences that may flow on to the rest of the ecosystem.This research has been funded by the Spanish Ministry of Science and Innovation (projects CTM2010-22273- C02-01 and 02). The Consejo Superior de Investigaciones Científicas (CSIC) supported A.G. (scholarship JAEPre_08_00466) and the Spanish Ministry of Education supported J.P. (scholarship AP2008-01601).Peer reviewe