284 research outputs found
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Agriculture modifies the seasonal decline of breeding success in a tropical wild bird population
1.Habitat conversion for agriculture is a major driver of biodiversity loss, but our understanding of the demographic processes involved remains poor. We typically investigate the impacts of agriculture in isolation even though populations are likely to experience multiple, concurrent changes in the environment (e.g. land and climate change). Drivers of environmental change may interact to affect demography but the mechanisms have yet to be explored fully in wild populations.
2.Here, we investigate the mechanisms linking agricultural land-use with breeding success using long-term data for the formerly Critically Endangered Mauritius kestrel Falco punctatus; a tropical forest specialist that also occupies agricultural habitats. We specifically focused on the relationship between breeding success, agriculture and the timing of breeding because the latter is sensitive to changes in climatic conditions (spring rainfall), and enables us to explore the interactive effects of different (land and climate) drivers of environmental change.
3.Breeding success, measured as egg survival to fledging, declines seasonally in this population, but we found that the rate of this decline became increasingly rapid as the area of agriculture around a nest site increased. If the relationship between breeding success and agriculture was used in isolation to estimate the demographic impact of agriculture it would significantly under-estimate breeding success in dry (early) springs, and over-estimate breeding success in wet (late) springs.
4.Analysis of prey delivered to nests suggests that the relationship between breeding success and agriculture might be due, in part, to spatial variation in the availability of native, arboreal geckos.
5.Synthesis and applications. Agriculture modifies the seasonal decline in breeding success in this population. As springs are becoming wetter in our study area and since the kestrels breed later in wetter springs, the impact of agriculture on breeding success will become worse over time. Our results suggest that forest restoration designed to reduce the detrimental impacts of agriculture on breeding may also help reduce the detrimental effects of breeding late due to wetter springs. Our results therefore highlight the importance of considering the interactive effects of environmental change when managing wild populations
Is cost-related non-collection of ? Findings from a large-scale longitudinal study of New Zealand adults
Objective: To investigate whether cost-related noncollection of prescription medication is associated with a decline in health. Settings: New Zealand Survey of Family, Income and Employment (SoFIE)-Health.
Participants: Data from 17 363 participants with at least two observations in three waves (2004-2005, 2006-2007, 2008-2009) of a panel study were analysed using fixed effects regression modelling.
Primary outcome measures: Self-rated health (SRH), physical health (PCS) and mental health scores (MCS) were the health measures used in this study.
Results: After adjusting for time-varying confounders, non-collection of prescription items was associated with a 0.11 (95% CI 0.07 to 0.15) unit worsening in SRH, a 1.00 (95% CI 0.61 to 1.40) unit decline in PCS and a 1.69 (95% CI 1.19 to 2.18) unit decline in MCS. The interaction of the main exposure with gender was significant for SRH and MCS. Non-collection of prescription items was associated with a decline in SRH of 0.18 (95% CI 0.11 to 0.25) units for males and 0.08 (95% CI 0.03 to 0.13) units for females, and a decrease in MCS of 2.55 (95% CI 1.67 to 3.42) and 1.29 (95% CI 0.70 to 1.89) units for males and females, respectively. The interaction of the main exposure with age was significant for SRH. For respondents aged 15-24 and 25-64 years, noncollection of prescription items was associated with a decline in SRH of 0.12 (95% CI 0.03 to 0.21) and 0.12 (95% CI 0.07 to 0.17) units, respectively, but for respondents aged 65 years and over, non-collection of prescription items had no significant effect on SRH.
Conclusion: Our results show that those who do not collect prescription medications because of cost have an increased risk of a subsequent decline in health
Review of UK biodiversity indicators that provide status and trends for species
The quality assurance panel was convened to provide advice on improvements that could be made to a suite of UK biodiversity indicators that are used to assess the status and trends of a range of species, and which are linked in turn to a range of biodiversity targets
CLARE - Ecolimits building ecosystem services for poverty alleviation
Gaining access to long-term production data is one of the biggest challenges to climate change adaptation policy planning. The project team successfully engaged the government in the analysis and review process of the Ghana Cocoa Board’s long-term big data sets (over seventy years of production data at multiple scales). Analysis improved the capacity of key stakeholders to understand the inter-relationships between the environment /climate, farming, and people’s lives and livelihoods. The process helped consolidate in-country partnerships including with the Forestry Commission, Cocoa Board, Forestry Research Institute of Ghana, Environment Protection Agency, relevant District Assemblies and Tropenbos Ghana
Abdominal fat depots associated with insulin resistance and metabolic syndrome risk factors in black African young adults
Abstract
Background
Individuals of black African ethnicity tend to have less visceral adipose tissue (VAT) but more subcutaneous-abdominal adipose tissue (SCAT) than white Caucasians. However, it is unclear whether such distribution of abdominal fat is beneficial for metabolic disease risk in black individuals. Here we compared the associations between these specific abdominal fat depots, insulin sensitivity and metabolic syndrome risk.
Methods
A cross-sectional analysis of 76 black South African young adults (36 men; 40 women) aged 18–19 years participating in the Birth to Twenty Cohort Study had VAT and SCAT measured by MRI. The metabolic syndrome traits (blood pressure, lipid profile, fasting glucose and insulin) were measured and the values were combined into a metabolic syndrome risk score. Fasting glucose and insulin were used to derive the HOMA-index of insulin resistance (HOMA-IR).
Results
Compared to men, women had greater VAT (mean: 16.6 vs. 12.5 cm2) and SCAT (median 164.0 vs. 59.9 cm2). In men, SCAT (r = 0.50) was more strongly correlated to the metabolic syndrome score (MetS) than was VAT (r = 0.23), and was associated with both MetS (P = 0.001) and HOMA-IR (P = 0.001) after adjustment for VAT and total fat mass. In women, both abdominal fat compartments showed comparable positive correlations with MetS (r = 0.26 to 0.31), although these trends were weaker than in men.
Conclusions
In young black South African adults, SCAT appears to be more relevant than VAT to metabolic syndrome traits
Carbon-Enhanced Metal-Poor Stars in the Inner and Outer Halo Components of the Milky Way
(Abridged) Carbon-enhanced metal-poor (CEMP) stars in the halo components of
the Milky Way are explored, based on accurate determinations of the
carbon-to-iron ([C/Fe]) abundance ratios and kinematic quantities for over
30000 calibration stars from the Sloan Digital Sky Survey (SDSS). Using our
present criterion that low-metallicity stars exhibiting [C/Fe] ratios
("carbonicity") in excess of [C/Fe] are considered CEMP stars, the
global frequency of CEMP stars in the halo system for \feh\ is 8%; for
\feh\ it is 12%; for \feh\ it is 20%. We also confirm a
significant increase in the level of carbon enrichment with declining
metallicity, growing from $\sim +1.0$ at \feh\ $= -1.5$ to
at \feh\ . The nature of the carbonicity
distribution function (CarDF) changes dramatically with increasing distance
above the Galactic plane, Z. For Z kpc, relatively few CEMP
stars are identified. For distances Z kpc, the CarDF exhibits a
strong tail towards high values, up to [C/Fe] +3.0. We also find a clear
increase in the CEMP frequency with Z. For stars with [Fe/H] 1.5, the frequency grows from 5% at Z kpc to 10% at Z
kpc. For stars with [Fe/H] 2.0, the frequency grows from 8% at
Z kpc to 25% at Z kpc. For stars with
[Fe/H] $\sim +1.0$ for 0 kpc $<$
$|$Z$|$ $<$ 10 kpc, with little dependence on $|$Z$|$; for [Fe/H] $< -$2.0,
, again roughly independent of Z.Comment: Accepted for publication in the Astrophysical Journal, 32 pages, 15
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Individual repeatability of avian migration phenology: a systematic review and meta-analysis
Changes in phenology and distribution are being widely reported for many migratory species in response to shifting environmental conditions. Understanding these changes and the situations in which they occur can be aided by understanding consistent individual differences in phenology and distribution and the situations in which consistency varies in strength or detectability. Studies tracking the same individuals over consecutive years are increasingly reporting migratory timings to be a repeatable trait, suggesting that flexible individual responses to environmental conditions may contribute little to population-level changes in phenology and distribution. However, how this varies across species and sexes, across the annual cycle and in relation to study (tracking method, study design) and/or ecosystem characteristics is not yet clear. Here, we take advantage of the growing number of publications in movement ecology to perform a phylogenetic multilevel meta-analysis of repeatability estimates for avian migratory timings to investigate these questions. Of 2,433 reviewed studies, 54 contained suitable information for meta-analysis, resulting in 177 effect sizes from 47 species. Individual repeatability of avian migratory timings averaged 0.414 (95% confidence interval: 0.3-0.5) across landbirds, waterbirds and seabirds, suggesting consistent individual differences in migratory timings is a common feature of migratory systems. Timing of departure from the non-breeding grounds was more repeatable than timings of arrival at or departure from breeding grounds, suggesting that conditions encountered on migratory journeys and outcome of breeding attempts can influence individual variation. Population-level shifts in phenology could arise through individual timings changing with environmental conditions and/or through shifts in the numbers of individuals with different timings. Our findings suggest that, in addition to identifying the conditions associated with individual variation in phenology, exploring the causes of between-individual variation will be key in predicting future rates and directions of changes in migratory timings. We therefore encourage researchers to report the within- and between- individual variance components underpinning the reported repeatability estimates to aid interpretation of migration behaviour. In addition, the lack of studies in the tropics means that levels of repeatability in less strongly seasonal environments are not yet clear
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