17 research outputs found
Extreme events are more likely to affect the breeding success of lesser kestrels than average climate change
Climate change is predicted to severely impact interactions between prey, predators and habitats. In
Southern Europe, within the Mediterranean climate, herbaceous vegetation achieves its maximum
growth in middle spring followed by a three-month dry summer, limiting prey availability for
insectivorous birds. Lesser kestrels (Falco naumanni) breed in a time-window that matches the
nestling-rearing period with the peak abundance of grasshoppers and forecasted climate change may
impact reproductive success through changes in prey availability and abundance. We used Normalised
Difference Vegetation Index (NDVI) as a surrogate of habitat quality and prey availability to investigate
the impacts of forecasted climate change and extreme climatic events on lesser kestrel breeding
performance. First, using 14 years of data from 15 colonies in Southwestern Iberia, we linked fledging
success and climatic variables with NDVI, and secondly, based on these relationships and according
to climatic scenarios for 2050 and 2070, forecasted NDVI and fledging success. Finally, we evaluated
how fledging success was influenced by drought events since 2004. Despite predicting a decrease in
vegetation greenness in lesser kestrel foraging areas during spring, we found no impacts of predicted
gradual rise in temperature and decline in precipitation on their fledging success. Notwithstanding, we
found a decrease of 12% in offspring survival associated with drought events, suggesting that a higher
frequency of droughts might, in the future, jeopardize the recent recovery of the European population.
Here, we show that extreme events, such as droughts, can have more significant impacts on species
than gradual climatic changes, especially in regions like the Mediterranean Basin, a biodiversity and
climate change hotspotinfo:eu-repo/semantics/publishedVersio
Southeastern U.S. Vegetation Response to ENSO Events (1989â1999)
El Niño/Southern Oscillation (ENSO) is considered one of the most powerful forces driving anomalous global weather patterns. Large-scale seasonal precipitation and temperature changes influenced by ENSO have been examined in many areas of the world. The southeastern United States is one of the regions affected by ENSO events. In this study, remote sensing detection of vegetation response to ENSO phases is demonstrated with one-kilometer biweekly Normalized Difference Vegetation Index (NDVI) data (1989â1999) derived from the Advanced Very High Resolution Radiometer (AVHRR). The impacts of three ENSO phases, cold, warm and neutral, on vegetation were analyzed with a focus on two vegetation cover types, two seasons and two geographic regions within the southeastern U.S. Significant ENSO effects on vegetation were found in cropland and forest vegetation cover types based on image and statistical analysis of the NDVI data. The results indicate that vegetation condition was optimal during the ENSO neutral phase for both agricultural and natural vegetatio
Quantifying the Anthropogenic Signature in Drylands of Central Asia and Its Impact on Water Scarcity and Dust Emissions
Humans have been changing the environment word-wide. Central Asia is a great example of a region that is strongly affected by human (anthropogenic) related activities. Political and economic transformations that have been occurring throughout the region have also been strongly affecting the environment. As a result, unprecedented changes have occurring in the land-use and -cover dynamics, as well as in water use and water availability for crops and human. Anthropogenic changes in Central Asia have significant consequences to the environment and human well-being. This chapter focuses on characterizing anthropogenic signatures in Central Asia, addressing their adverse consequences to the population and the environment of Central Asia. Sections address the anthropogenic dust emission associated with human activities, anthropogenic water use, and human growth. The anthropogenic dust emission is reconstructed by taking into account the changes in the land-cover and land use that have been caused by various human activities, including the drying up of the Aral Sea. The latter is a well-known human made disaster that has a profound impact on the entire region. Drastic changes have been occurring in the water use. The population dynamic causes additional problems. We investigated the rate of change in the intensity of the stable average lights product between 1991 and 2000. While the total percentage of lit land increased (3.1â3.4%) between 1991 and 2000, almost all lit areas in Kazakhstan declined in night light intensity. The only areas with increasing nightlights are some of the core urban areas, the Kenkiyak oil fields south of Aktobe and another oil field to the north of Kyzylorda
Ecological covariates of Ascaris lumbricoides infection in schoolchildren from rural KwaZulu-Natal, South Africa.
OBJECTIVES: To identify environmental factors that could serve to predict Ascaris lumbricoides infection patterns and thus guide control efforts in the absence of epidemiological information; to assess whether A. lumbricoides infection is positively associated with the soil clay content. METHODS: Information on A. lumbricoides infection and re-infection in a cohort of primary schoolchildren and interview data on their socioeconomic background and behaviour were combined with environmental data using a geographical information system (GIS). Multivariate models served to explore the covariation of environmental and infection patterns adjusted for possible confounders. RESULTS: Prevalence maps and spatial statistics revealed considerable spatial clustering of infection in the small study area. Logistic multivariate regression models showed strong positive associations of infection with vegetation density measured as the normalized difference vegetation index (NDVI) at baseline [odds ratio (OR) for a 10% increase: 1.82; 95% confidence interval (95% CI): 1.24-2.68; P=0.002] and after re-infection (OR: 2.22; 95% CI: 1.71-2.87; P<0.001). We also found a strong negative association of re-infection with the sun exposure of the soil surface as estimated from digital elevation models (OR: 0.78; 95% CI: 0.88; P<0.001). The soil clay content was only moderately positively associated with infection and re-infection. Socioeconomic and behavioural variables, although correlated with A. lumbricoides infection, did not appear to confound the above associations in the demographically homogeneous study area. Spatial analysis of the model residuals suggested that as the models accounted for most of the spatial pattern, the model standard errors should not be affected by spatial clustering. CONCLUSION: NDVI seems to have a high potential for the prediction of A. lumbricoides infection as it was strongly associated with infection patterns in the study area. Further advantages are that NDVI information is easy to use, affordable and available with global coverage