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We measured the background level and spatial variation of carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) and associated basic soil parameters along the depth profile for 3 years, in 3 habitats (woodland, wetland, and grassland), in Keoladeo National Park (KNP), an important water fowl reserve and a world heritage site in India. The study examined soils at 5 depths (0, 0.25, 0.50, 0.75 and 1.0 m) for 3 years, i.e. from 2003 to 2005. Total organic C (TOC), total N (TN), total available P (TAP), and total available S (TAS), irrespective of the habitat type and year, were found to be highest in the litter layer, gradually declining with depth. Elemental ratios (C : N, C : P, and C : S) followed the same declining trend, whereas the N : P ratio increased down the soil profile. The high C : N and C : S ratios in the litter layer suggest the relatively low mobilisation of N and S from the decaying detritus layer. All the variables studied varied significantly among the soil layers (GLM-ANOVA, P < 0.05). Principal component analysis (PCA) showed 4 components based on examination of the scree plot. The first component accounted for 27.1% of the total variance in soil characteristics among samples, reflecting the influence of soil variables such as P, TOC, and pH. The second component accounted for 23.5% of the total variance, reflecting the influence of total dissolved solids (TDS) and TAS. The influence of C on elemental ratio (C : S) was pointed by the third component, accounted for 14.2% of the total variance. The fourth component accounted for 13.6% of the variance, indicating the influence of soil TN. Thus, the 4 PCA components that accounted for 78.4% of the total variance in the data can be qualified as N : P/soil P/C, TDS/TAS, C : S ratio, and soil TN, respectively.

In this study, 24 breast milk samples, obtained from rural Maya women, from municipalities of Yucatan, Mexico, were analyzed for organochlorine pesticide (OCP) residues by gas chromatography. Recent studies have shown that Maya communities have a poor perception about the proper usage and handling of OCP. The karstic soil in this area has a high vulnerability to groundwater pollution by the use of OCP in agriculture and livestock activities. The impact of the ecosystem on human health is much more critical due to the prevailing poverty and a very low educational level of these communities. About 30% of the Maya population consumes water directly from contaminated wells and sinkholes, resulting in a chronic exposure to OCP. The samples served to identify and quantify high levels of OCP residues (18.43 mg/kg of heptachlor epoxide and 1.92 mg/kg of endrin in the metropolitan zone; 2.10 mg/kg of dieldrin, 0.117 mg/kg of endosulfan II, 0.103 mg/kg of heptachlor, 0.178 mg/kg of endrin, and 0.127 mg/kg of endrin aldehyde in the main agricultural zone and on the west coast). The detected levels of OCP residues are a major concern and represent a potential risk to women and children in the region. This could be associated with the high rates of cervical uterine and breast cancer mortality in Yucatan. Thus, regulations on the usage of OCP and their enforcement are necessary, and it is important to establish a yearly monitoring program for OCP residues in breast milk and groundwater, as well as to implement health promotion programs for women in particular and the general population in general.

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We examined the ammonium acetate extractable forms of alkali (Na, K) and alkaline earth (Ca, Li, and Mg) metals in the soil system in a world heritage site, Keoladeo National Park, Bharatpur, India for 3 consecutive years—2003, 2004, and 2005. The metals were assessed along the soil profile, from surface to 1.00 m depth (as 5 layers, at 0, 0.25, 0.50, 0.75, and 1.00 m). Sodium and K were negatively correlated (P < 0.05) and were found in the range 40–4533 and 77–1802 mg/kg, respectively. The distributions of these metals were significantly different among habitats (Na: F = 17.035, K: F = 30.56; P < 0.05). The lowest and highest values of Ca were 548 and 5976 mg/kg, and for Mg 230 and 5654 mg/kg. The variation in Ca was significant among the soil layers (F = 11.9) and among the habitats (F = 117.3, P < 0.05). Li was found in the range 1.74–15.00 mg/kg soil and varied significantly among the soil layers (F = 71.7) as well as habitats (F = 105.9, P < 0.05). Potassium was positively correlated with Ca, Li, and Mg during 2004 and 2005 (P < 0.05). The terrestrial areas in the Park had higher values of Na/K ratio, indicating the dominating presence of Na salts. Calcium-type enrichment in the wetland and Na-type enrichment in the woodland and grassland differentiated the soil in the Park. A low Mg/Ca molar ratio with a range 0.089–1.681 suggests that CaCO3 rocks would not be the major source of Ca in this Park. Since some of the elements were comparatively higher in the soil, the phytocycling of biogenic elements such as Mg and Ca would ultimately improve the fertility status of the soil system in the Park. Although not addressed here, this issue needs to be considered.

Background Habitat heterogeneity clearly distinguished in terms of availability of food and habitat resources and landscape features (natural or human-modified) play a crucial role in the avian species composition and population structure. To examine this, a study was carried out in Bhubaneswar, India, to understand the ecological niche distinction in birds based on habitat heterogeneity. Regular sampling was conducted in 30 sampling sites covering six different habitat types in a predominantly urban landscape of Bhubaneswar for understanding the ecological niche in birds. The birds were classified into 11 types of foraging guilds. Results The insectivorous guild had the highest bird species richness (181 species) and the omnivorous guild had the lowest (11 species). The piscivorous guild and wetland habitat had the strongest linkage, followed by the insectivorous guild and agricultural land. The frugivorous guild was significantly correlated with forest habitats (r = 0.386, p < 0.01) and park and garden habitats (r = 0.281, p < 0.01). This urban area hosted a higher number of bird species in certain habitat types, viz., agricultural lands (52%, 115 species) and forest patches (50%, 111 species). Conclusion The present study highlights the importance of agricultural lands, forest patches, parks and gardens, and wetlands inside the cityscape for supporting avifauna. It is therefore suggested that such habitats should be conserved inside an urban area to protect native avifauna. Thus, the city development plan must invariably include strategies for conserving the forest patches inside the urban area. Measures must be taken to restrain the degradation of agricultural lands and reduce their utilization for non-agricultural purposes, which will help in further reducing the bird population decline in the urban landscape.

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