189 research outputs found
Impacts on a threatened bird population of removals for translocation
The removal of individuals from a population may occur for several reasons and responses of populations will vary depending on the magnitude and nature of the removal and the life history of the species. An understanding of the effects of loss of individuals on these populations, and the mechanism of replacement, will be important to conservation. This maybe particularly important where wild individuals are used for the increasingly popular conservation strategy of translocation. During the recent translocation of the endangered eastern bristlebird (Dasyornis brachypterus), two monitoring sites were established in the wild source population, one where removals were to take place and another as a control to assess the impact of the removals on the population. The removal of 44 eastern bristlebirds across 3 years from a single area in the source population had no significant detectable impact in the numbers of individuals surveyed. Individuals that were removed appeared to have been replaced within 6 months of their removal, although to a lesser extent in the later part of the study. The origin of the replacement eastern bristlebirds was unknown and the quick recovery was suggested to be a result of juvenile dispersal, perhaps combined with territory uptake by previously non-territorial and non-calling (thus undetectable) individuals within the population. Such a surplus may be a result of insufficient suitable habitat for population expansion, and will also have implications for monitoring populations of rare and cryptic species. It is also suggested that some territorial species may have several mechanisms that can replace losses of individuals from a population
Spatial and temporal variation of papyrus root mat thickness and water storage in a tropical wetland system
acceptedVersio
Condition index monitoring supports conservation priorities for the protection of threatened grass-finch populations
Conservation agencies are often faced with the difficult task of prioritizing what recovery actions receive support. With thenumber of species under threat of decline growing globally, research that informs conservation priorities is greatly needed. Therelative vulnerability of cryptic or nomadic species is often uncertain, because populations are difficult to monitor and localpopulations often seem stable in the short term. This uncertainty can lead to inaction when populations are in need of protection.We tested the feasibility of using differences in condition indices as an indication of population vulnerability to decline forrelated threatened Australian finch sub-species. The Gouldian finch represents a relatively well-studied endangered species,which has a seasonal and site-specific pattern of condition index variation that differs from the closely related non-declininglong-tailed finch. We used Gouldian and long-tailed finch condition variation as a model to compare with lesser studied, threatenedstar and black-throated finches. We compared body condition (fat and muscle scores), haematocrit and stress levels (corticosterone) among populations, seasons and years to determine whether lesser studied finch populations matched the modelof an endangered species or a non-declining species. While vulnerable finch populations often had lower muscle and higher fatand corticosterone concentrations during moult (seasonal pattern similar to Gouldian finches), haematocrit values did not differamong populations in a predictable way. Star and black-throated finch populations, which were predicted to be vulnerableto decline, showed evidence of poor condition during moult, supporting their status as vulnerable. Our findings highlight howmeasures of condition can provide insight into the relative vulnerability of animal and plant populations to decline and willallow the prioritization of efforts towards the populations most likely to be in jeopardy of extinctio
Combined column test for characterization of leaching and transport of trace elements in contaminated soils
publishedVersio
Current insecticide treatments used in locust control have less of a short-term impact on Australian arid-zone reptile communities than does temporal variation
Author version made available in accordance with the publisher's policyContext: Despite the regular use of pesticides to control locusts, there is a general lack of information on the effects of locust control treatments on reptiles worldwide. Exposure to pesticides poses a significant potential hazard to reptiles, particularly small lizards, both from the direct effects of exposure, and indirectly due to their largely insectivorous diet and small home ranges.
Aims: Our study aimed to monitor the effects of two insecticides applied operationally for locust control in Australia.A phenyl pyrazole pesticide, fipronil, and a fungal biopesticide, Metarhizium anisopliae var. acridium (Green Guard®) were applied aerially in either a barrier or block treatment in the absence of high density locust populations, and effects on non-target Australian arid-zone reptiles were measured.
Methods: We monitored reptile abundance and community composition responses to treatment methods using a large field-based pitfall trapping experiment with replicated control and spraying treatments which approximated the scale of aerial-based locust control operations in Australia.
Key results: Neither reptile abundance nor community composition was significantly affected by locust control treatments. However, both abundance and community composition as detected by pitfall trapping changed over time, in both control and treatment plots, possibly due to a decrease in annual rainfall during the two years of the study.
Conclusions: The absence of any significant short-term pesticide treatment effects in our study suggests that the two locust control application methods studied present a relatively insignificant hazard to reptiles at our site, based on a single application. Similar to other areas of Australia, climate or climate driven vegetation change are likely to be stronger drivers of reptile abundance and community structure.
Implications: Monitoring over an area which approximates the scale of current locust control operations is an important step in understanding the possible effects of current pesticide exposure on reptile populations and will inform insecticide risk assessments in Australia. However, important information on the immediate response of individuals to insecticide application and any longer-term effects of exposure are still missing. The preliminary research reported in this paper should be complemented by future investigations on long-term and sublethal impacts of pesticide exposure on Australian native reptiles and the possible benefits provided to reptiles by the resource pulses represented in untreated high-density locust population
Modelling Plume Development with Annual Pulses of Contaminants Released from an Airport Runway to a Layered Aquifer, Evaluation of an In Situ Monitoring System
publishedVersio
Increasing weight-bearing physical activity and calcium-rich foods to promote bone mass gains among 9–11 year old girls: outcomes of the Cal-Girls study
BACKGROUND: A two-year, community-based, group-randomized trial to promote bone mass gains among 9–11 year-old girls through increased intake of calcium-rich foods and weight-bearing physical activity was evaluated. METHODS: Following baseline data collection, 30 5th-grade Girl Scout troops were randomized to a two-year behavioral intervention program or to a no-treatment control group. Evaluations were conducted at baseline, one year, and two years. Measures included bone mineral content, density, and area (measured by DXA), dietary calcium intake (24-hour recall), and weight-bearing physical activity (physical activity checklist interview). Mixed-model regression was used to evaluate treatment-related changes in bone mineral content (g) for the total body, lumbar spine (L1-L4), proximal femur, one-third distal radius, and femoral neck. Changes in eating and physical activity behavioral outcomes were examined. RESULTS: Although the intervention was implemented with high fidelity, no significant intervention effects were observed for total bone mineral content or any specific bone sites. Significant intervention effects were observed for increases in dietary calcium. No significant intervention effects were observed for increases in weight-bearing physical activity. CONCLUSION: Future research needs to identify the optimal dosage of weight-bearing physical activity and calcium-rich dietary behavior change required to maximize bone mass gains in pre-adolescent and adolescent girls
New Orleans’ school meals distribution in response to the COVID-19 pandemic: operational details and geographic coverage
IntroductionTo facilitate continuation of school feeding during COVID-19 school lockdowns, U.S. Congress authorized waivers to allow for school meals to be picked up by parents/guardians in non-school settings. We summarized school meals distribution and characterized reach in socially vulnerable neighborhoods in New Orleans, a city prone to environmental disasters, with a city-wide charter school system, and historically high levels of child poverty and food insecurity.MethodsSchool meals operations data were obtained from New Orleans, Louisiana (NOLA) Public Schools for 3/16/2020–5/31/2020. For each pick-up location, we estimated: average meals available (weekly), average meals served (weekly), number of weeks of operation, and rate of meal pick-up ([meals served/meals available]*100). These characteristics were mapped in QGIS v3.28.3, along with neighborhoods’ Social Vulnerability Index (SVI). Pearson correlation and ANOVA were run to assess differences between operations characteristics and neighborhood SVI.ResultsFrom 38 meal sites, 884,929 meals were available for pick-up; 74% of pick-up sites were in moderately/highly socially vulnerable areas. Correlations between average meals available and served, weeks of operation, rate of meal pick-up, and SVI were weak and not statistically significant. SVI was associated with average rate of meal pick-up but not other operations characteristics.DiscussionDespite the disaggregated nature of the charter school system, NOLA Public Schools successfully pivoted to providing children with pick-up meals due to COVID-19 lockdowns, with 74% of sites located in socially vulnerable neighborhoods. Future studies should describe the types of meals provided to students during COVID-19, in terms of diet quality and nutrient adequacy
Miljøvennlig drift av sykkelveinettet i Oslo Miljøeffekter av formiatbaserte avisningsmidler – Resultater fra vannkjemiske og biologiske undersøkelser vinteren 2018.
Hvert år brukes det omtrent 7000 tonn vegsalt (MgCl2 og NaCl) på kommunale veger i Oslo. På grunn av de negative effektene som vegsalt kan ha, og med bakgrunn i bystyrevedtak fra 2012 om at Oslo kommune skal erstatte vegsalt med mer miljøvennlige alternativer, ønsker Bymiljøetaten å teste ut alternative miljøvennlige avisningsmidler på veg- og sykkelvegnettet. Fra februar 2018 ble natriumformiat benyttet som avisningsmiddel på Eterveien og en del av Østensjøveien langs Østensjøvannet i Oslo. Innløpsbekkene til innsjøen ble overvåket gjennom testperioden. Formiat forbruker oksygen ved nedbrytning, men ut fra sesongens resultater er det ingenting som tyder på at tilførsel av formiat har forårsaket oksygenmangel, hverken i sidebekkene eller i Østensjøvannet. Effektene av formiat på vegetasjon er vanskelig å si noe konkret om da det ble brukt vanlig vegsalt og formiat samme sesong. Systematiske undersøkelser av saltskader på vegetasjon gjennom vinteren, hyppigere prøvetaking i bekkene, samt kontinuerlig overvåking ved utløpet til Østesjøvannet er noen av tiltakene som foreslås for videreføringen av prosjektet vinteren 2018/2019.publishedVersio
Experimental admixture among geographically disjunct populations of an invasive plant yields a global mosaic of reproductive incompatibility and heterosis
1. Invasive species have the ability to rapidly adapt in the new regions where they are introduced. Classic evolutionary theory predicts that the accumulation of genetic differences over time in allopatric isolation may lead to reproductive incompatibilities resulting in decreases in reproductive success and, eventually, to speciation. However, experimental evidence for this theoretical prediction in the context of invasive species is lacking. We aimed to test for the potential of allopatry to determine reproductive success of invasive plants, by experimentally admixing genotypes from six different native and non‐native regions of Centaurea solstitialis, an invasive forb for which preliminary studies have detected some degree of reproductive isolation between one native and non‐native region.
2. We grew plants under common garden conditions and outcrossed individuals originating from different source populations in the native and introduced range to evaluate reproductive success in terms of seed to ovule ratio produced. We also assessed geographical and genetic isolation among C. solstitialis regions as a potential driving factor of reproductive success.
3. Experimental admixture generated mixed fitness effects, including significant increases, decreases and no differences in reproductive success as compared to crosses within population (control). Centaurea solstitialis invasive populations in the Americas generated preponderantly negative fitness interactions, regardless of the pollen source, suggesting selection against immigrants and reinforcement. Other non‐native populations (Australia) as well as individuals from the native range of Spain demonstrated an increase in fitness for between‐region crosses, indicating inbreeding. These differences show an asymmetrical response to inter‐regional gene flow, but no evidence of isolation by distance.
4. Synthesis. The speed of adaptation and the accumulation of reproductive incompatibilities among allopatric populations of invasive species might be more rapid than previously assumed. Our data show a global mosaic of reproductive outputs, showcasing an array of evolutionary processes unfolding during colonization at large biogeographical scales
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