Isotopic niche overlap between sympatric Australian snubfin and humpback dolphins

Ecological niche theory predicts the coexistence of closely related species is promoted by resource partitioning in space and time. Australian snubfin (Orcaella heinsohni) and humpback (Sousa sahulensis) dolphins live in sympatry throughout most of their range in northern Australian waters. We compared stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in their skin to investigate resource partitioning between these ecologically similar species. Skin samples were collected from live Australian snubfin (n = 31) and humpback dolphins (n = 23) along the east coast of Queensland in 2014–2015. Both species had similar δ13C and δ15N values and high (>50%) isotopic niche space overlap, suggesting that they feed at similar trophic levels, have substantial dietary overlap, and rely on similar basal food resources. Despite similarities, snubfin dolphins were more likely to have a larger δ15N value than humpback dolphins, indicating they may forage on a wider diversity of prey. Humpback dolphins were more likely to have a larger δ13C range suggesting they may forage on a wider range of habitats. Overall, results suggest that subtle differences in habitat use and prey selection are likely the principal resource partitioning mechanisms enabling the coexistence of Australian snubfin and humpback dolphins

Corrigendum: Abundance and Potential Biological Removal of Common Dolphins Subject to Fishery-Impacts in South Australian Waters

Conservation management of wildlife species should be underpinned by knowledge of their distribution and abundance, as well as impacts of human activities on their populations and habitats. Common dolphins (Delphinus delphis) are subject to incidental capture in a range of Australia’s commercial fisheries including gill netting, purse seining and mid-water trawling. The impact these fishery interactions have on common dolphin populations is uncertain, as estimates of abundance are lacking, particularly for the segments of the populations at risk of bycatch and in greater need of protection. Here we used double-observer platform aerial surveys and mark-recapture distance sampling methods to estimate the abundance of common dolphins in 2011 over an area of 42,438 km2 in central South Australia, where incidental mortality of common dolphins due to fisheries bycatch is the highest. We also used the potential biological removal (PBR) method to estimate sustainable levels of human-caused mortality for this segment of the population. The estimated abundance of common dolphins was 21,733 (CV = 0.25; 95% CI = 13,809–34,203) in austral summer/autumn and 26,504 in winter/spring (CV = 0.19; 95% CI = 19,488–36,046). Annual PBR estimates, assuming a conservative maximum population growth rate of Rmax = 0.02 and a recovery factor of Fr = 0.5 for species of unknown conservation status, ranged from 95 (summer/autumn) to 120 dolphins (winter/spring), and from 189 (summer/autumn) to 239 dolphins (winter/spring) with an Rmax = 0.04. Our results indicate that common dolphins are an abundant dolphin species in waters over the central South Australian continental shelf (up to 100 m deep). Based on the 2011 abundance estimates of this species, the highest estimated bycatch of common dolphins (423 mortalities in 2004/05) in the southern Australian region exceeded the precautionary PBR estimates for this population segment. Recent bycatch levels appear to be below PBR estimates, but low observer coverage and underreporting of dolphin mortalities by fishers means that estimates of dolphin bycatch rates are not robust. The effects of cumulative human impacts on common dolphins are not well understood, and thus we recommend a precautionary management approach to manage common dolphin bycatch based on local abundance estimates

Demographic characteristics of Australian humpback dolphins reveal important habitat toward the southwestern limit of their range

Open Access under Creative Commons by Attribution Licence. Use, distribution and reproduction are un-restricted. Authors and original publication must be credited.ABSTRACT: The paucity of information on the recently described Australian humpback dolphin Sousa sahulensis has hindered assessment of its conservation status. Here, we applied capture-recapture models to photo-identification data collected during boat-based surveys between 2013 and 2015 to estimate the abundance, site fidelity and residence patterns of Australian humpback dolphins around the North West Cape (NWC), Western Australia. Using Pollock’s closed robust design, abundance estimates varied from 65 to 102 individuals, and POPAN open modelling yielded a super-population size of 129 individuals in the 130 km2 study area. At approximately 1 humpback dolphin per km2, this density is the highest recorded for this species. Temporary emigration was Markovian, suggesting seasonal movement in and out of the study area. Hierarchical clustering showed that 63% of individuals identified exhibited high levels of site fidelity. Analysis of lagged identification rates indicated dolphins use the study area regularly, following a movement model characterised by emigration and re-immigration. These density, site fidelity and residence patterns indicate that the NWC is an important habitat toward the southwestern limit of this species’ range. Much of the NWC study area lies within a Marine Protected Area, offering a regulatory framework on which to base the management of human activities with the potential to impact this threatened species. Our methods provide a methodological framework to be used in future environmental impact assessments, and our findings represent a baseline from which to develop long-term studies to gain a more complete understanding of Australian humpback dolphin population dynamics

Road Network Planning in Tropical Forests Using GIS

This study intended to develop a road network planning for timber harvesting in tropical forests in Peru using georeferenced and field data and Geographic Information System (GIS). The Digital Elevation Model (DEM) Alos Palsar 12.5 m was used. The DEM was processed to generate the hydrography and terrain slope maps. A weighted raster was created using overlapping weights of the slope raster and the hydrography map. We created a least cost path raster by using the weighted raster origin and destination points. We used a Triangular Irregular Network (TIN) to validate the Least Cost Path. In addition, histograms of the trajectory of each path with altitude and slope values were generated. We observed that the forest road planning using GIS provided better definition (economically and environmentally) of road networks in our forest site than those traditionally defined using conventional mapping techniques

Efficacy of zinc lactate and Lactobacillus bulgaricus on nutrition and health of broiler chickens

This investigation examined the effects of zinc lactate and Lactobacillus bulgaricus supplementation on the gastrointestinal microbiota of broiler chickens, analysing zootechnical, allometric, microbiological parameters and small intestine morphology. A total of 300 broiler chickens with an average initial weight of 47 g were distributed in four treatments in a completely randomised design. Treatments consisted of different zinc lactate and probiotic amounts added to the base diet. Chickens receiving the basal diet with organic zinc and L. bulgaricus showed a healthy response, remaining free of infectious agents for the 42-day study period. Treatment T1, with 30 mg of zinc lactate and 10 mg of probiotics per kg, showed improvements in weight gain, feed conversion, allometry, and intestinal health, as well as a healthy presence of gastrointestinal microbiota. Thus, the incorporation of zinc lactate (organic Zn) and probiotics based on L. bulgaricus into the basal diet of broiler chickens is an effective strategy to improve sanitary conditions and organic production of these species. Highlights: From: Efficacy of zinc lactate and Lactobacillus bulgaricus on nutrition and health of broiler chickens. Innovative Supplementation Strategy: This study presents an innovative approach by combining zinc lactate and Lactobacillus bulgaricus in broiler chickens' diet, showcasing a novel method to enhance poultry health and organic production. Comprehensive Analysis of Gut Microbiota: The research provides a detailed analysis of the gastrointestinal microbiota, demonstrating how zinc lactate and Lactobacillus bulgaricus supplementation positively alters the gut environment in broiler chickens. Significant Improvements in Zootechnical Parameters: The study highlights notable improvements in zootechnical parameters, including weight gain and feed conversion ratios, underlining the efficacy of the supplementation strategy. Enhanced Intestinal Morphology: Examination of the small intestine morphology revealed significant health benefits, attributing these improvements to the synergistic effect of organic zinc and probiotic supplementation. Pathogen-Free Development over 42 Days: A key finding is the maintenance of a healthy, pathogen-free state in chickens throughout the 42-day study period, emphasizing the potential of this supplementation in promoting disease resistance in poultry farming.This investigation examined the effects of zinc lactate and Lactobacillus bulgaricus supplementation on the gastrointestinal microbiota of broiler chickens, analysing zootechnical, allometric, microbiological parameters and small intestine morphology. A total of 300 broiler chickens with an average initial weight of 47 g were distributed in four treatments in a completely randomised design. Treatments consisted of different zinc lactate and probiotic amounts added to the base diet. Chickens receiving the basal diet with organic zinc and L. bulgaricus showed a healthy response, remaining free of infectious agents for the 42-day study period. Treatment T1, with 30 mg of zinc lactate and 10 mg of probiotics per kg, showed improvements in weight gain, feed conversion, allometry, and intestinal health, as well as a healthy presence of gastrointestinal microbiota. Thus, the incorporation of zinc lactate (organic Zn) and probiotics based on L. bulgaricus into the basal diet of broiler chickens is an effective strategy to improve sanitary conditions and organic production of these species. Highlights: From: Efficacy of zinc lactate and Lactobacillus bulgaricus on nutrition and health of broiler chickens. Innovative Supplementation Strategy: This study presents an innovative approach by combining zinc lactate and Lactobacillus bulgaricus in broiler chickens' diet, showcasing a novel method to enhance poultry health and organic production. Comprehensive Analysis of Gut Microbiota: The research provides a detailed analysis of the gastrointestinal microbiota, demonstrating how zinc lactate and Lactobacillus bulgaricus supplementation positively alters the gut environment in broiler chickens. Significant Improvements in Zootechnical Parameters: The study highlights notable improvements in zootechnical parameters, including weight gain and feed conversion ratios, underlining the efficacy of the supplementation strategy. Enhanced Intestinal Morphology: Examination of the small intestine morphology revealed significant health benefits, attributing these improvements to the synergistic effect of organic zinc and probiotic supplementation. Pathogen-Free Development over 42 Days: A key finding is the maintenance of a healthy, pathogen-free state in chickens throughout the 42-day study period, emphasizing the potential of this supplementation in promoting disease resistance in poultry farming

Green roofs : contribution of Carpobrotus Acinaciformis to the integrated management of urban surface runoff

En el marco de la modelización matemática de las cuencas hídricas urbanas, uno de los parámetros que es necesario conocer, son los factores en la cuenca que pueden modificar la escorrentía superficial. Las Cubiertas Naturadas pueden (a partir de su capacidad de retención y retardo de los escurrimientos originados por las precipitaciones), modificar la escorrentía superficial. Pero en qué medida pueden hacerlo, dependerá de la respuesta de dichas estructuras vegetadas a la cantidad precipitada y esta respuesta será diferente según el tipo de cubierta utilizada (básicamente espesor del sustrato y tipo de vegetación). Por eso en los modelos matemáticos de simulación, la modelización será más precisa en función de la precisión de los datos fuentes utilizados en la misma. El objetivo de este trabajo ha sido determinar la capacidad de retención que presentan las cubiertas naturadas de tipo extensivo e intensivo implantadas con Carpobrotus acinaciformis. Los resultados obtenidos permitirían afirmar, para las condiciones estudiadas, que el Carpobrutus acinaciformis, puede realizar un aporte a la disminución de los escurrimientos urbanos para ciudades ubicadas en la costa bonaerense como la de este trabajo.In the mathematical modeling of urban watershed, the parameters that are necessary to know, are the factors of the basin that can modify the surface runoff. The green roofs can modify (from its capacity of retention and delay the water flow originated by the rainfalls), the superficial run-off. But the magnitude that they can do it, will depend on the response of the above mentioned green roofs to the rainfalls, and this response will be different according to the type of green roof (basically substrate thickness and type of vegetation). Because of it, in the mathematical simulation models, the modeling will be more precise depending on the precision of the information sources used. The aim of this work has been to determine the capacity of retention that present green roof, extensive and intensive, planted with Carpobrotus acinaciformis. The results would allow affirming, for the studied conditions, that the Carpobrutus acinaciformis, can realize a contribution to the decrease of the urban runoffs for cities located in the Buenos Aires coast as that of this work.Fil: Villalba, Gustavo Ariel. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería AgrícolaFil: Rosatto, Héctor Gustavo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería AgrícolaFil: Bienvenido, Fernando. Universidad de AlmeríaFil: Flores-Parra, Isabel María. Universidad de AlmeríaFil: Botta, Guido Fernando. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería AgrícolaFil: Laureda, Daniel Andrés. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería AgrícolaFil: Perez, Damián Andrés. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería Agrícol

Too Close for Comfort? Isotopic Niche Segregation in New Zealand’s Odontocetes

Species occurring in sympatry and relying on similar and limited resources may partition resource use to avoid overlap and interspecific competition. Aotearoa, New Zealand hosts an extraordinarily rich marine megafauna, including 50% of the world’s cetacean species. In this study, we used carbon and nitrogen stable isotopes as ecological tracers to investigate isotopic niche overlap between 21 odontocete (toothed whale) species inhabiting neritic, mesopelagic, and bathypelagic waters. Results showed a clear niche separation for the bathypelagic Gray’s beaked whales (Mesoplodon grayi) and sperm whales (Physeter macrocephalus), but high isotopic niche overlap and potential interspecific competition for neritic and mesopelagic species. For these species, competition could be reduced via temporal or finer-scale spatial segregation or differences in foraging behaviour. This study represents the first insights into the coexistence of odontocetes in a biodiverse hotspot. The data presented here provide a critical baseline to a system already ongoing ecosystem change via ocean warming and subsequent effects on prey abundance and distributions

High site fidelity and restricted ranging patterns in southern Australian bottlenose dolphins

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Information on site fidelity and ranging patterns of wild animals is critical to understand how they use their environment and guide conservation and management strategies. Delphinids show a wide variety of site fidelity and ranging patterns. Between September 2013 and October 2015, we used boat‐based surveys, photographic identification, biopsy sampling, clustering analysis, and geographic information systems to determine the site‐fidelity patterns and representative ranges of southern Australian bottlenose dolphins (Tursiops cf. australis) inhabiting the inner area of Coffin Bay, a highly productive inverse estuary located within Thorny Passage Marine Park, South Australia. Agglomerative hierarchical clustering (AHC) of individuals’ site‐fidelity index and sighting rates indicated that the majority of dolphins within the inner area of Coffin Bay are “regular residents” (n = 125), followed by “occasional residents” (n = 28), and “occasional visitors” (n = 26). The low standard distance deviation indicated that resident dolphins remained close to their main center of use (range = 0.7–4.7 km, X ± SD = 2.3 ± 0.9 km). Representative ranges of resident dolphins were small (range = 3.9–33.5 km2, X ± SD = 15.2 ± 6.8 km2), with no significant differences between males and females (Kruskal–Wallis, χ2 = 0.426, p = .808). The representative range of 56% of the resident dolphins was restricted to a particular bay within the study area. The strong site fidelity and restricted ranging patterns among individuals could be linked to the high population density of this species in the inner area of Coffin Bay, coupled with differences in social structure and feeding habits. Our results emphasize the importance of productive habitats as a major factor driving site fidelity and restricted movement patterns in highly mobile marine mammals and the high conservation value of the inner area of Coffin Bay for southern Australian bottlenose dolphins

Prevalencia de infraoclusión en molares primarios de niños de 7 y 8 años, Valdivia, Chile, 2019

Objetivo: Determinar la prevalencia de infraoclusión en molares primarios de niños de 7 y 8 años, Valdivia, Chile. Materiales y métodos: Estudio descriptivo de corte transversal. Se examinaron niños de 7 y 8 años en establecimientos educacionales de Valdivia. Fue evaluada la presencia y severidad de infraoclusión en molares primarios utilizando la clasificación de Brearley & McKibben. Para establecer diferencias estadísticas entre sexo y presencia de infraoclusión fue realizada la prueba de chi-cuadrado. Además un análisis de ANOVA fue utilizado para establecer diferencias entre la localización de la infraoclusión y el grado de severidad. El nivel de significancia estadística se estableció con un valor de p<0,05. Resultados: Fueron evaluados 359 niños y un 41,78% presentó infraoclusión. Según grado de severidad, 82,06% fueron leves, 15,28% moderadas y 2,66% severas. No se encontraron diferencias significativas entre sexo y presencia de infraoclusión. Se evidenciaron diferencias estadísticamente significativas al evaluar localización y grado de severidad (p<0,05). Conclusión: Existe una alta prevalencia de infraoclusión en niños de 7 y 8 años en Valdivia, Chile