scholarly journals Bottom-up effects of a no-take zone on endangered penguin demographics

2015 ◽  
Vol 11 (7) ◽  
pp. 20150237 ◽  
Author(s):  
Richard B. Sherley ◽  
Henning Winker ◽  
Res Altwegg ◽  
Carl D. van der Lingen ◽  
Stephen C. Votier ◽  
...  
Keyword(s):  
Prey Availability ◽  
Spatial Scales ◽  
Adult Mortality ◽  
Chick Survival ◽  
Target Species ◽  
Management Tools ◽  
Bottom Up ◽  
Marine Predators ◽  
Spheniscus Demersus ◽  
African Penguin

Marine no-take zones can have positive impacts for target species and are increasingly important management tools. However, whether they indirectly benefit higher order predators remains unclear. The endangered African penguin ( Spheniscus demersus ) depends on commercially exploited forage fish. We examined how chick survival responded to an experimental 3-year fishery closure around Robben Island, South Africa, controlling for variation in prey biomass and fishery catches. Chick survival increased by 18% when the closure was initiated, which alone led to a predicted 27% higher population compared with continued fishing. However, the modelled population continued to decline, probably because of high adult mortality linked to poor prey availability over larger spatial scales. Our results illustrate that small no-take zones can have bottom-up benefits for highly mobile marine predators, but are only one component of holistic, ecosystem-based management regimes.

scholarly journals Developing a Hazomalania voyronii Essential Oil Nanoemulsion for the Eco-Friendly Management of Tribolium confusum, Tribolium castaneum and Tenebrio molitor Larvae and Adults on Stored Wheat

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1812
Author(s):  
Nickolas G. Kavallieratos ◽  
Erifili P. Nika ◽  
Anna Skourti ◽  
Nikoletta Ntalli ◽  
Maria C. Boukouvala ◽  
...  
Keyword(s):  
Public Health ◽  
Food Safety ◽  
Essential Oil ◽  
Tenebrio Molitor ◽  
Adult Mortality ◽  
Tribolium Confusum ◽  
Target Species ◽  
Management Tools ◽  
Stored Product Pests ◽  
Tenebrio Molitor Larvae

Most insecticides commonly used in storage facilities are synthetic, an issue that generates concerns about food safety and public health. Therefore, the development of eco-friendly pest management tools is urgently needed. In the present study, a 6% (w/w) Hazomalania voyronii essential oil-based nanoemulsion (HvNE) was developed and evaluated for managing Tribolium confusum, T. castaneum, and Tenebrio molitor, as an eco-friendly wheat protectant. Larval and adult mortality was evaluated after 4, 8, and 16 h, and 1, 2, 3, 4, 5, 6, and 7 days, testing two HvNE concentrations (500 ppm and 1000 ppm). T. confusum and T. castaneum adults and T. molitor larvae were tolerant to both concentrations of the HvNE, reaching 13.0%, 18.7%, and 10.3% mortality, respectively, at 1000 ppm after 7 days of exposure. However, testing HvNE at 1000 ppm, the mortality of T. confusum and T. castaneum larvae and T. molitor adults 7 days post-exposure reached 92.1%, 97.4%, and 100.0%, respectively. Overall, the HvNE can be considered as an effective adulticide or larvicide, depending on the target species. Our results highlight the potential of H. voyronii essential oil for developing green nanoinsecticides to be used in real-world conditions against key stored-product pests.

scholarly journals Capillary Electrophoresis Assessment of Plasma Protein Changes in an African Penguin (Spheniscus demersus) With Aspergillosis

ACS Omega ◽  
2020 ◽  
Vol 5 (51) ◽  
pp. 33280-33289
Author(s):  
Anddre Osmar Valdivia ◽  
Kristen Jasmin Ortega ◽  
Sanjoy K. Bhattacharya ◽  
Carolyn Cray
Keyword(s):  
Capillary Electrophoresis ◽  
Plasma Protein ◽  
Spheniscus Demersus ◽  
African Penguin

scholarly journals Predictors of invertebrate biomass and rate of advancement of invertebrate phenology across eight sites in the North American Arctic

Polar Biology ◽  
2021 ◽  
Vol 44 (2) ◽  
pp. 237-257
Author(s):  
Rebecca Shaftel ◽  
Daniel J. Rinella ◽  
Eunbi Kwon ◽  
Stephen C. Brown ◽  
H. River Gates ◽  
...  
Keyword(s):  
Prey Availability ◽  
Population Level ◽  
The Arctic ◽  
Environmental Drivers ◽  
Chick Survival ◽  
The North ◽  
Phenological Mismatch ◽  
Nesting Sites ◽  
North American Arctic

AbstractAverage annual temperatures in the Arctic increased by 2–3 °C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of shorebirds and the invertebrate prey essential for egg formation and subsequent chick survival. To explore the environmental drivers affecting invertebrate availability, we modeled the biomass of invertebrates captured in modified Malaise-pitfall traps over three summers at eight Arctic Shorebird Demographics Network sites as a function of accumulated degree-days and other weather variables. To assess climate-driven changes in invertebrate phenology, we used data from the nearest long-term weather stations to hindcast invertebrate availability over 63 summers, 1950–2012. Our results confirmed the importance of both accumulated and daily temperatures as predictors of invertebrate availability while also showing that wind speed negatively affected invertebrate availability at the majority of sites. Additionally, our results suggest that seasonal prey availability for Arctic shorebirds is occurring earlier and that the potential for trophic mismatch is greatest at the northernmost sites, where hindcast invertebrate phenology advanced by approximately 1–2.5 days per decade. Phenological mismatch could have long-term population-level effects on shorebird species that are unable to adjust their breeding schedules to the increasingly earlier invertebrate phenologies.

Genetic monitoring of ex situ African Penguin (Spheniscus demersus) populations in South Africa

2016 ◽  
Vol 51 (2) ◽  
pp. 83-90 ◽  
Author(s):  
Christiaan Labuschagne ◽  
Lisa Nupen ◽  
Antoinette Kotzé ◽  
J Paul Grobler ◽  
Desiré L Dalton
Keyword(s):  
South Africa ◽  
Genetic Monitoring ◽  
Ex Situ ◽  
Spheniscus Demersus ◽  
African Penguin

scholarly journals Scales of Food Availability for an Endangered Insectivore, The Hawaii Akepa

The Auk ◽  
2002 ◽  
Vol 119 (1) ◽  
pp. 166-174 ◽  
Author(s):  
J. Scott Fretz
Keyword(s):  
Food Availability ◽  
Prey Availability ◽  
Spatial Scales ◽  
Canopy Cover ◽  
Distribution Patterns ◽  
Prey Population ◽  
Suitable Habitat ◽  
Population Declines ◽  
Loxops Coccineus ◽  
A Site

Abstract The Hawaii Akepa (Loxops coccineus coccineus) is an endangered bird that has declined dramatically in the last 100 years, and is now rare or absent from many areas that appear to support suitable habitat. Food availability may play a role in these distribution patterns, but differences in food between sites may arise from different sources. I compared prey availability between a site supporting a large, stable Hawaii Akepa population, and a site from which Hawaii Akepa have declined in the last 100 years for unknown reasons. I used three spatial scales to compare food between sites to explore the basis of differences in food between sites. At a scale appropriate for comparing prey population dynamics (scale 1), I found that prey population densities are similar between sites, suggesting that introduced (or native) predators or parasitoids have not affected prey populations differently between sites. At two larger scales incorporating habitat structure, I found that food availability is much lower at the site of Hawaii Akepa declines. Differences in canopy density per square meter (scale 2), and in canopy cover per square kilometer (scale 3), result in lower food availability that may have effects on individual foraging birds as well as on potential Hawaii Akepa population density. These findings illustrate the importance of explicitly incorporating spatial scale into inquiries about food for Hawaii Akepa, and suggest that the site of population declines may not be suitable habitat with respect to food for this species.

scholarly journals Parasite diversity associated with African penguins (Spheniscus demersus) and the effect of host and environmental factors

Parasitology ◽  
2019 ◽  
Vol 146 (6) ◽  
pp. 791-804 ◽  
Author(s):  
Marcela P. A. Espinaze ◽  
Cang Hui ◽  
Lauren Waller ◽  
Francois Dreyer ◽  
Sonja Matthee
Keyword(s):  
Environmental Factors ◽  
Nest Density ◽  
Western Coast ◽  
Helminth Parasites ◽  
Limited Information ◽  
Parasite Diversity ◽  
Critically Endangered Species ◽  
Temperature And Precipitation ◽  
Spheniscus Demersus ◽  
African Penguin

AbstractThe African penguin (Spheniscus demersus) is a critically endangered species endemic to southern Africa. Limited information is available on the parasite diversity associated with the species in natural settings. This study explores the diversity and incidence of parasites associated with African penguins and their nests, and records the effect of host and environmental factors on parasite infestation. Ecto-, haemo- and helminth parasites were recorded from 210 adult birds, 583 chicks and 628 nests across five colonies (two mainland and three islands) along the south-western coast of South Africa, in 2016 and 2017. Mean nest density (total and active nests) and climate variables (temperature and precipitation) were obtained for each colony. Parapsyllus humboldti was the most abundant and prevalent ectoparasite on penguins and in nests (69.10 and 57.80%, respectively), while Piroplasmorida/Haemospororida (33.51%) and Cardiocephaloides spp. (56.17%) were the most prevalent haemo- and helminth parasites of penguins, respectively. In general parasite abundance and prevalence was significantly affected by penguin age (chicks vs adults), location (mainland vs islands), nest density (total and active nests) and season (spring vs autumn/winter). It is concluded that parasite infestations are structured and that penguin chicks at mainland colonies are more susceptible to parasite infestations during spring.

scholarly journals Bayesian inference reveals positive but subtle effects of experimental fishery closures on marine predator demographics

2018 ◽  
Vol 285 (1871) ◽  
pp. 20172443 ◽  
Author(s):  
Richard B. Sherley ◽  
Barbara J. Barham ◽  
Peter J. Barham ◽  
Kate J. Campbell ◽  
Robert J. M. Crawford ◽  
...  
Keyword(s):  
South Africa ◽  
Bayesian Inference ◽  
Population Growth ◽  
Prey Availability ◽  
Population Level ◽  
Marine Ecosystems ◽  
Forage Fish ◽  
Chick Survival ◽  
Marine Predator ◽  
Management Interventions

Global forage-fish landings are increasing, with potentially grave consequences for marine ecosystems. Predators of forage fish may be influenced by this harvest, but the nature of these effects is contentious. Experimental fishery manipulations offer the best solution to quantify population-level impacts, but are rare. We used Bayesian inference to examine changes in chick survival, body condition and population growth rate of endangered African penguins Spheniscus demersus in response to 8 years of alternating time–area closures around two pairs of colonies. Our results demonstrate that fishing closures improved chick survival and condition, after controlling for changing prey availability. However, this effect was inconsistent across sites and years, highlighting the difficultly of assessing management interventions in marine ecosystems. Nevertheless, modelled increases in population growth rates exceeded 1% at one colony; i.e. the threshold considered biologically meaningful by fisheries management in South Africa. Fishing closures evidently can improve the population trend of a forage-fish-dependent predator—we therefore recommend they continue in South Africa and support their application elsewhere. However, detecting demographic gains for mobile marine predators from small no-take zones requires experimental time frames and scales that will often exceed those desired by decision makers.

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