Increased Recruitment Success Research Articles

Simulated distribution of Eragrostis lehmanniana (Lehmann lovegrass): Soil–climate interactions complicate predictions

AbstractThe invasive perennial grass Eragrostis lehmanniana has expanded rapidly throughout the Sonoran Desert (SD) while remaining sparse and patchily distributed in the neighboring Chihuahuan Desert (CD). As temperatures and patterns in precipitation change, identifying the drivers limiting spread in the CD is needed. Our objectives were (1) to identify the climatic and edaphic factors limiting recruitment of E. lehmanniana throughout the CD and (2) to predict the edaphic and climatic locations in the CD where this species is expected to have higher probabilities of recruitment under future climatic conditions. Recruitment was simulated at 57 locations throughout the CD with a daily, multilayer soil water model (SOILWAT) that was parameterized and tested to develop recruitment parameters for E. lehmanniana using long‐term data from research stations in the SD and CD. Logistic regression was used to predict recruitment across the CD using climate and soil factors to create a map of simulated recruitment under current and alternative climate scenarios. Simulated recruitment under current climate was low for most of the CD. However, localized areas with high probabilities (>0.8) occurred along the western transition between the CD and the SD, and in the southern extent of the CD. In general, the CD climate is too cool and dry for rapid and widespread invasion. However, increases to temperature and precipitation are likely to increase recruitment success. Interactions among soil, temperature, and precipitation were important to increases in recruitment of E. lehmanniana and are expected to lead to heterogeneous increases in abundance as climate continues to change. This patchy increase in abundance will result in changes in its geographic distribution that will make predictions in the future challenging.

The influence of climatic and lunar drivers on landings cycles of the temperate Australian sciaenid (Atractoscion atelodus) at two temporal scales: A working hypothesis for future management of this resource

Commercial line-fishing catch rates of the endemic sciaenid Atractoscion atelodus in eastern-Australia were significantly affected by lunar phase. Periodic regression analysis indicated that catch rates were greatest during the full moon period and lowest during the new moon period. It is hypothesized that this observation is the result of the visual nocturnal feeding nature of A. atelodus, with schools of fish using the increased ambient light in the water column during the brighter part of the lunar phase to feed intensively. Increased feeding intensity during the brighter phase of the lunar month may also be related to spawning activity during the new moon phase; however this hypothesis remains to be tested. Annual commercial landings through a 71 year dataset (1950–2020) showed an approximately exponential decline, overlaid with periodic years of higher and lower landings. Such periods of higher landings were significantly positively correlated with coastal rainfall two and three years earlier, but not with rainfall in the same year or one, four or five years earlier. We hypothesize that increased coastal rainfall, likely in combination with unknown co-occurring factors, promotes increased recruitment success of A. atelodus, potentially through increased primary productivity in the nearshore marine environment. This translates into an increase in the fishable stock mainly two and three years later. If our hypothesis is correct, climate predictions of reduced rainfall in eastern Australia suggest a pessimistic outlook for this fishery.

Harnessing health plan enrollee data to boost membership in patient-powered research networks

BackgroundPatient-powered research networks (PPRNs) have been employing and exploring different methods to engage patients in research activities specific to their conditions. One way to intensify patient engagement is to partner with payer stakeholders. The objective of this study was to evaluate the effectiveness of two common payer-initiated outreach methods (postal mail versus email) for inviting prospective candidates to participate in their initiatives.MethodsThis descriptive study linked members of a nationally-representative private insurance network to four disease-specific PPRN registries. Eligible members meeting diagnostic criteria who were not registered in any of the four PPRNs by 02/28/2018 were identified, and randomly assigned to either the mail or email group. They were contacted in two outreach efforts: first on 04/23/2018, and one follow-up on 05/23/2018. New registration rates by outreach method as of 8/31/2018 were determined by relinking. We compared registrants and non-registrants using bivariate analysis.ResultsA total of 14,571 patients were assigned to the mail group, and 14,574 to the email group. Invitations were successfully delivered to 13,834 (94.9%) mail group and 10,205 (70.0%) email group members. A small but significantly larger proportion of mail group members, (n = 78; 0.54, 95% Confidence Interval [CI] {0.42–0.67%}) registered in PPRNs relative to the email group (n = 24; 0.16, 95% CI {0.11–0.25%}), p < 0.001. Members who registered had more comorbidities, were more likely to be female, and had marginally greater medical utilization, especially emergency room visits, relative to non-registrants (52.0% vs. 42.5%, p = 0.05).ConclusionA health plan outreach to invite members to participate in PPRNs was modestly effective. Regular mail outperformed less costly email. Providing more value-add to participants may be a possible way to increase recruitment success.

Effect of larval swimming in the western North Pacific subtropical gyre on the recruitment success of the Japanese eel.

The possible effect of directional larval swimming on the recruitment success of the Japanese eel, Anguilla japonica, was examined with a three-dimensional particle-tracking ocean circulation model using horizontal northwestward swimming and diel vertical migration (DVM). Four separate experiments included virtual larvae (v-larvae) movement from the spawning area over 290 days (total migration) and 160 days (stage A), from the STCC eddy region in 70 days (stage B), and from the origin of the Kuroshio in 60 days (stage C) to evaluate the effect of directional swimming and DVM compared to simple drifting. Passive or random swimming were not the most effective strategies for larvae dispersing from the spawning area because most v-larvae remained south of 20°N without entering the Kuroshio. Northwestward swimming resulted in wider dispersion and a better chance of successful recruitment, with v-larvae becoming widely distributed in the STCC eddy zone, arriving at the east coast of the Philippines (stage A), escaping the STCC eddy area and reaching the Kuroshio (stage B), and crossing the Kuroshio into the East China Sea shelf (stage C). DVM slightly shortened the migration period due to faster shallow layer ocean currents during nighttime. The NEC transported non-swimming v-larvae westward to the Kuroshio and occasionally northward into the Subtropical Countercurrent (STCC) area where eddies transported v-larvae westward into the Kuroshio, but less than with swimming. Directional swimming increased recruitment success, northwestward swimming was more effective than other directions, and a slower swimming speed was still better than no/random swimming in sensitivity tests. The present study demonstrated a first view of the possibility that Japanese eel larvae might be able to use a strategy of single-direction swimming to increase arrival at their recruitment areas.

Lessons Learned Recruiting Minority Participants for Research in Urban Community Health Centers

To help understand and mitigate health disparities, it is important to conduct research with underserved and underrepresented minority populations under real world settings. There is a gap in the literature detailing real-time research staff experience, particularly in their own words, while conducting in-person patient recruitment in urban community health centers. This paper describes challenges faced at the clinic, staff, and patient levels, our lessons learned, and strategies implemented by research staff while recruiting predominantly low-income African-American women for an interviewer-administered survey study in four urban Federally Qualified Health Centers in New Jersey. Using a series of immersion-crystallization cycles, fieldnotes and research reflections written by recruiters, along with notes from team meetings during the study, were qualitatively analyzed. Clinic level barriers included: physical layout of clinic, very low or high patient census, limited private space, and long wait times for patients. Staff level barriers included: unengaged staff, overburdened staff, and provider and staff turnover. Patient level barriers included: disinterested patients, patient mistrust and concerns over confidentiality, no-shows or lack of patient time, and language barrier. We describe strategies used to overcome these barriers and provide recommendations for in-person recruitment of underserved populations into research studies. To help mitigate health disparities, disseminating recruiters' experiences, challenges, and effective strategies used will allow other researchers to build upon these experience in order to increase recruitment success of underserved and underrepresented minority populations into research studies.

Climate warming could increase recruitment success in glacier foreland plants.

Glacier foreland plants are highly threatened by global warming. Regeneration from seeds on deglaciated terrain will be crucial for successful migration and survival of these species, and hence a better understanding of the impacts of climate change on seedling recruitment is urgently needed to predict future plant persistence in these environments. This study presents the first field evidence of the impact of climate change on recruitment success of glacier foreland plants. Seeds of eight foreland species were sown on a foreland site at 2500 m a.s.l., and at a site 400 m lower in altitude to simulate a 2·7°C increase in mean annual temperature. Soil from the site of origin was used to reproduce the natural germination substrate. Recruitment success, temperature and water potential were monitored for 2 years. The response of seed germination to warming was further investigated in the laboratory. At the glacier foreland site, seedling emergence was low (0 to approx. 40%) and occurred in summer in all species after seeds had experienced autumn and winter seasons. However, at the warmer site there was a shift from summer to autumn emergence in two species and a significant increase of summer emergence (13-35% higher) in all species except two. Survival and establishment was possible for 60-75% of autumn-emerged seedlings and was generally greater under warmer conditions. Early snowmelt in spring caused the main ecological factors enhancing the recruitment success. The results suggest that warming will influence the recruitment of glacier foreland species primarily via the extension of the snow-free period in spring, which increases seedling establishment and results in a greater resistance to summer drought and winter extremes. The changes in recruitment success observed here imply that range shifts or changes in abundance are possible in a future warmer climate, but overall success may be dependent on interactions with shifts in other components of the plant community.

Recruitment strategies should not be randomly selected: empirically improving recruitment success and diversity in developmental psychology research.

Psychological and developmental research have been critiqued for the lack of diversity of research samples. Because differences in culture, race, and ethnicity can influence participant behavior, limited diversity limits the generalizability of the findings. These differences may also impact how participants behave in response to recruitment attempts, which suggests that recruitment itself may be leveraged to increase sample diversity. The goal of the current study was to determine what factors, within a recruitment interaction, could be leveraged to increase success and diversity when recruiting families with children for developmental research. Study 1 found three factors influenced success: (1) recruitment was more successful when other potential participants were also interested (i.e., recruiters were busy), (2) recruiters of particular races were more successful than recruiters of other races, and (3) differences in success were related to what the recruiter said to engage the potential participant (i.e., the script). The latter two factors interacted, suggesting some recruiters were using less optimal scripts. To improve success rates, study 2 randomly assigned scripts to recruiters and encouraged them to recruit more vigorously during busy periods. Study 2 found that two factors influenced success: (1) some scripts were more successful than others and (2) we were more successful at recruiting non-White potential participants than White participants. These two interacted, with some scripts being more successful with White and other scripts being more successful with non-White families. This intervention significantly increased recruitment success rate by 8.1% and the overall number of families recruited by 15.3%. These findings reveal that empirically evaluating and tailoring recruitment efforts based on the most successful strategies is effective in boosting diversity through increased participation of children from non-White families.

When anthropogenic‐related disturbances overwhelm demographic persistence mechanisms

Summary Population decline is associated with increased vulnerability to extinction, but also with possible density‐, frequency‐ or distance‐related ‘rarity advantages’ that increase recruitment success as individuals become isolated from their congeners. Distinguishing between these alternatives (risk vs. recovery of rare populations via demographic processes) has become critical, given how anthropogenic disturbances are causing population declines globally. Here, we demonstrate how distance‐related rarity advantages are evident in spatially isolated recruits of a canopy‐dominant but regionally rare species of oak that appears to be suffering recruitment collapse. As distance from parent trees increased, seedlings had significantly more leaves and experienced reduced insect browsing and intraspecific competition. Long‐term field‐based experimental treatments revealed these advantages to be associated with rapid rates of juvenile maturation and survival that are unobserved in natural settings. The discrepancy between the experimental and natural settings was explained by trophic collapse and habitat loss – two changes ubiquitous to many terrestrial ecosystems – that combine to concentrate vertebrate herbivores in habitat remnants and cause 100% juvenile mortality via the browsing of taller juveniles. Exotic grass cover, long associated with oak recruitment failure, significantly suppressed seedling height and leaf production, but appeared to delay mortality by hiding shorter seedlings from vertebrate herbivores. Synthesis. Our work demonstrates how rarity advantages have the potential to positively influence the population performance of a declining species, but are short‐circuited by intense herbivory associated with human‐based environmental change. Regionally, there appear to be few existing conditions on the contemporary landscape that favour juvenile survival, suggesting ongoing recruitment difficulties without intervention. Our work clarifies how extinction risk can in some cases be best defined by how anthropogenic disturbances affect, and are offset by, demographic‐based persistence mechanisms, than simply by present‐day abundance or distribution.

Latitudinal variation of migratory life histories of riverine Galaxias maculatus in Chile (36°- 47°S)

Event Abstract Back to Event Latitudinal variation of migratory life histories of riverine Galaxias maculatus in Chile (36°- 47°S) Konrad Górski1, 2*, Evelyn M. Habit2 and Aliro J. Manosalva2 1 Universidad Católica de la Santísima Concepción, Departamento de Ecología, Chile 2 Universidad de Concepción, Facultad de Ciencias Ambientales, Chile A relationship between life histories and increasing latitude has been described for Northern Hemisphere riverine fish, whereby life cycles that complete most of the growth in the ocean are favoured at higher latitudes. In the riverine ecosystems of the Southern Hemisphere many species of galaxiids display highly flexible migratory life histories and the mechanisms driving employment of different strategies remain unclear. Our objective was to assess the mechanisms driving the selection of migratory strategies of Galaxias maculatus from rivers across a gradient of latitude. Fifteen fish from three size classes as well as water samples were collected from upper, middle and lower sections of 10 river systems in Chile across latitudes 36°- 47°S. Otoliths and water samples were analysed for a suite of trace elements using Laser Ablation Inductively Coupled Plasma Mass Spectrometry. Otolith elemental composition was analysed through depth profiling to assess the frequency of marine migrations in each section of each river. The propensity of marine migrations was strongly related to latitude as well as flow and temperature dynamics of each river system. Fish in river systems at higher latitudes more frequently displayed use of marine and brackish habitats, potentially enabling them to maximise foraging opportunities and increase recruitment success. River systems originating from large Andean lakes with more predictable flow pattern (large scale spring floodplain inundations and therefore more predictable food supplies) accommodated more resident individuals with no marine signatures even at higher latitudes. Therefore, climate as well as both longitudinal (headwaters-estuary) and lateral (main channel-floodplains) hydrologic connectivity seem to govern migratory strategies of riverine Galaxias maculatus. Consequently, management strategies that promote both lateral and longitudinal connectivity within riverine ecosystems are crucial to maximise habitat availability for this native fish species. Acknowledgements Financial support: Fondecyt 3130690, DIUC 213.310.063-1AP Keywords: Fish migration, Diadromy, LA-ICP-MS, Otolith microchemistry, Puye, īnanga Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Oral Presentation Topic: Otoliths as a tool to study fish life cycles Citation: Górski K, Habit EM and Manosalva AJ (2015). Latitudinal variation of migratory life histories of riverine Galaxias maculatus in Chile (36°- 47°S). Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.fmars.2015.03.00031 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Oct 2015; Published Online: 04 Nov 2015. * Correspondence: Dr. Konrad Górski, Universidad Católica de la Santísima Concepción, Departamento de Ecología, Concepción, Chile, konrad.gorski@uach.cl Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Konrad Górski Evelyn M Habit Aliro J Manosalva Google Konrad Górski Evelyn M Habit Aliro J Manosalva Google Scholar Konrad Górski Evelyn M Habit Aliro J Manosalva PubMed Konrad Górski Evelyn M Habit Aliro J Manosalva Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Maintenance of Certification Part 4 Credit and recruitment for practice-based research.

Competing priorities in pediatric practice have created challenges for practice-based research. To increase recruitment success, researchers must design studies that provide added value to participants. This study evaluates recruitment of pediatricians into a study, before and after the development and addition of a quality improvement (QI) curriculum approved for American Board of Pediatrics Maintenance of Certification (MOC) Part 4 Credit as an enrollment incentive. Researchers implemented multiple outreach methods to enroll pediatric practices over 28 months. Field note review revealed that many physicians declined enrollment, stating that they prioritized MOC Part 4 projects over research studies. A QI curriculum meeting standards for MOC Part 4 Credit was developed and added to the study protocol as an enrollment incentive. Enrollment rates and characteristics of practitioners enrolled pre- and post-MOC were compared. Pre-MOC enrollment contributed 48% of practices in 22 months; post-MOC enrollment contributed 49% of practices in 6 months. An average of 3.5 practices enrolled per month pre-MOC, compared with 13.1 per month post-MOC (P < .001). Clinicians in pre- and post-MOC groups were similar in age, gender, race, and time spent on patient care; practices enrolled post-MOC were more likely to be located in federally designated Medically Underserved Areas than those enrolled pre-MOC (28.6% vs 12%, P = .03). Addition of MOC Part 4 Credit increased recruitment success and increased enrollment of pediatricians working in underserved areas. Including QI initiatives meeting MOC Part 4 criteria in practice-based research protocols may enhance participation and aid in recruiting diverse practice and patient populations.

Environmental influences on the larval recruitment dynamics of snapper, Chrysophrys auratus (Sparidae)

Recruitment success in demersal fish species that settle in estuaries after a pelagic larval duration in coastal waters is dependent on (1) abiotic and biotic variables that promote good survival, and (2) local environmental conditions that facilitate and direct the transport of larvae to settlement habitats. In the present study, we described the patterns of larval abundance, pelagic larval duration and settlement of a commercially important sparid, Chrysophrys auratus, in northern New Zealand over 2 years, and investigated the relationships among pelagic larval duration or daily settler abundance and various environmental variables. Pelagic larval duration varied from 17 to 33 days and the successful spawning period that produced settled juveniles varied from 29 to 109 days among our four sites. For 91% of fish captured, the average temperature during the pelagic larval duration was &gt;18°C. Significant correlations between daily settler abundance and environmental variables varied among sites and between years; however, temperature, tidal range and on-shore winds were most strongly correlated with settlement, explaining up to 38% of the variability in settler abundance. The present results suggested that, in some locations, high water temperatures, large tides and on-shore winds are likely to increase recruitment success in C. auratus.

Temperature change and Baltic sprat: from observations to ecological-economic modelling

Temperature effects on Baltic sprat are many and include both direct and indirect effects. Increasing temperature is thought to increase the survival of all early life stages, resulting in increased recruitment success. We quantified the spatially resolved temperature trend for major spawning grounds and depth layers being most relevant for sprat eggs and larvae, using a three-dimensional hydrodynamic model for 1979–2005. Results confirmed an underlying positive temperature trend. Next, we tested these time-series as new explanatory variables in an existing temperature-dependent recruitment function and applied these recruitment predictions in an agestructured ecological–economic optimization model, maximizing for profit. Economic optimal solutions depended upon variability in temperature trajectories. Under climate-change scenarios, mean optimal fishing mortality and related yields and profits increased. The extent of the increase was limited by the general shape of the stock–recruitment model and the assumption of density-dependence. This highlights the need to formulate better environmentally sensitive stock recruitment models. Under the current knowledge of Baltic sprat recruitment, the tested climate-change scenarios would result in a change in management targets. However, to serve as a quantitative management advice tool, models will have to address the above-mentioned concerns

Nutrient enrichment promotes survival and dispersal of drifting fragments in an invasive tropical macroalga

The effect of nutrient availability on growth, survival, and photosynthetic performance of drifting fragments of the invasive red alga Hypnea musciformis was studied in Maui (Hawaii), where this species smothers native reef communities and forms localized blooms. H. musciformis does not sexually reproduce in Hawaii and drifting fragments represent the only pathway by which H. musciformis can disperse and invade new areas. Growth rates decreased with age and approached zero when fragments aged 32 days. Increased nutrient availability did not result in increased relative growth rates during this period. In contrast to growth, photosynthetic performance remained unaffected through time and showed no clear relationship with nutrient availability. Increased nutrient availability increased fragment survival and fragments survived for >2 months in the high nutrient treatment (3.0 μmolPO4 + 30.0 μmolNH4). This indicates that increased nutrient availability increases the dispersal potential of H. musciformis. Low growth rates of drifting Hypnea fragments increased recruitment success since attachment success of this epiphytic species decreased with increasing fragment size. H. musciformis thus uses resources for survival and maintenance rather than growth, resulting in long competency periods and optimal recruitment, which likely contribute to its success as an invader of Hawaiian reef communities.

Climate modulates the effects of Sardinella aurita fisheries off Northwest Africa

The fluctuating abundance of round sardinella ( Sardinella aurita) in Mauritanian waters over the past ca. 20 years can be related to environmental dynamics off Northwest Africa. Trends in the fishery are evaluated using FAO data, acoustic surveys, and catch statistics from the EU fleet (1996–2006). Remote sensing data demonstrate rising annual sea surface temperatures, up to 3 °C higher than the long-term average in 2002–2003, following a shift in ocean climate in 1995. Fish abundance and repeated expansion of the sardinella population in the past 10 years are attributed to favorable oceanographic conditions and increased recruitment success. Sardinella thrives with intense upwelling and high primary production during spring, and retention of waters over the shelf during summer and autumn. The stock of S. aurita over the Northwest African shelf oscillates with the cold–warm states of the habitat. Favorable hydrographic conditions and extended habitat has resulted in unprecedented rise of sardinella abundance in the late 1990s, which was counterbalanced by the impact of fisheries. A backshift to a cold-state ecosystem, with extensive regional upwelling and decreased sardinella habitat, would topple that balance.

Long-term changes in the geographic distribution and population structures of Osilinus lineatus (Gastropoda: Trochidae) in Britain and Ireland

Since the rate of global climate change began to accelerate in the 1980s, the coastal seas of Britain have warmed by up to 1°C. Locations close to the northern range edges of a southern trochid gastropod Osilinus lineatus in Britain previously surveyed in the 1950s and 1980s were resurveyed during 2002–2004 to determine whether changes in the success of near-limit populations had occurred during the period of climate warming. Between the 1980s and the 2000s, the range limits had extended by up to 55 km. Populations sampled over a latitudinal extent of 4 degrees from northern limits towards the centre of the range showed synchronous increases in abundance throughout the years sampled, suggesting a large-scale factor such as climate was driving the observed changes. These increases in abundance and changes in range limits are likely to have occurred via increased recruitment success in recent years.

Relationships between spawning date and larval development time for benthic marine invertebrates: a modeling approach

Marine larval biologists frequently assume that selection to shorten larval duration drives the evolution of reproductive strategies (e.g. egg size). If this assumption is correct, we would also expect larval duration to influence when adults spawn, because adult spawning time can influence the amount of food and temperatures larvae experience, and thus larval duration. Here we develop a simple model to predict development times for marine invertebrates with lecithotrophic larvae as a function of spawning date and sea-surface temperature for the NE Pacific Ocean. We focus on species with non-feeding (lecithotrophic) larvae because the duration of larval life is most influenced by seawater temperature alone. Because there are few empirical data on the relationship between larval development rate and temperature of lecithotrophic species, we used several different functions that represented a range of shapes. Our primary result reveals that the shape of the relationship of development rate to temperature has a pronounced influence on which spawning dates result in the shortest larval duration. For an increasing decelerating relationship, there is a broad range of spawning dates that minimize larval duration. This relationship did overlap with the empirical spawning data for lecithotrophic species in the region. However, for a linear and an increasing accelerating relationship, there is a narrower range of time that results in the shortest larval duration, and for these 2 relationships, observed spawning times did not match as well. Our model also predicted substantial inter-annual variation in development times for all relationships. In addition, we compared spawning times for species with planktotrophic and brooded larval development and found reproductive periods for species with planktotrophic larvae to be similar to those for lecithotrophic larvae, while species with brooded larvae are reproductive over broader periods. Our results suggest that earlier reproductive periods may be favored for reasons independent of development time, potentially including decreased larval predation and increased recruitment success.

The separate and combined effects of epibenthic predation and presence of macro-infauna on the recruitment success of bivalves in shallow soft-bottom areas on the Swedish west coast

Previous studies have shown a high year-to-year variability in recruitment success of bivalves. Especially after mild winters recruitment was generally low, but the lower egg production after mild winters in Macoma balthica could only explain 7% of its recruitment variance. In the present study, I tested the hypothesis that the combined effect of a high predation pressure together with a high abundance of adult macrofauna contributes to an explanation of the low recruitment success of bivalves after mild winters. In field experiments in shallow soft-bottom bays at the Swedish west coast, adult benthic fauna (mainly consisting of lugworms Arenicola marina and cockles Cerastoderma edule) was removed and predators (mainly shrimps Crangon crangon and crabs Carcinus maenas) were excluded in some plots/cages, whereas in other plots/cages high densities of adult lugworms or cockles and predators were present. Both the absence of adult macrofauna and the absence of predators increased recruitment success, but the effect of the combined absence of adult macrofauna and predators enhanced recruitment success even more. The combined presence of high macrofauna densities and high predation pressure reduced the recruitment success for Mya arenaria by about 80% compared to the situation in which adult macrofauna and predators were absent. For C. edule, spat densities the reduction was nearly 90% and for Tellinacea spat even about 95%. Thus failure in recruitment success after a mild winter can to a large extent be explained by the presence of high densities of adult macrofauna combined with high predation pressure.