Influence of tree size, reduced competition, and climate on the growth response of Pinus nigra Arn. salzmannii after fire

Context

After wildfire, surviving trees are of major ecological importance as they can help in the post-fire regeneration process. Although these trees may be damaged, they may also benefit from reduced fuel hazard and competition. However, little is known about the long-term growth response of surviving trees.

Aims

This study aims to explain short- to long-term variations in the postfire growth of surviving black pines in an area burnt in 1994, focusing on levels of fire severity and tree sizes.

Methods

Relative basal area increments were used to detect time-course variations in postfire radial tree growth depending on fire severity. Linear mixed-effects models were used to describe the factors affecting postfire ring growth.

Results

In the short term, fire caused stronger reduction in growth in small trees with increasing bole char height. However, as time since fire increased, a positive effect of fire on growth due to reduced competition counteracted the short-term fire impacts. Indeed, small surviving trees demonstrated a surge in growth 15 years after the fire.

Conclusion

It was concluded that reduced competition might offset the short-term negative effects of fire in surviving black pines.     

Carotenoid intakes, assessed by food-frequency questionnaires (FFQs), are associated with serum carotenoid concentrations in the Jackson Heart Study: validation of the Jackson Heart Study Delta NIRI Adult FFQs

OBJECTIVES: Intake and status of carotenoids have been associated with chronic disease. The objectives of this study were to examine the association between carotenoid intakes as measured by two regional food-frequency questionnaires (FFQs) and their corresponding measures in serum, and to report on dietary food sources of carotenoids in Jackson Heart Study (JHS) participants. DESIGN: Cross-sectional analysis of data for 402 African American men and women participating in the Diet and Physical Activity Sub-Study (DPASS) of the JHS. RESULTS: Mean serum carotenoid concentrations and intakes in this population were comparable to those reported for the general US population. After adjustment for covariates, correlations between serum and dietary measures of each carotenoid, for the average of the recalls (deattenuated), the short FFQ and the long FFQ, respectively, were: 035 and 0-carotene; 026 and 0-carotene; 017 and 0-carotene; 034 and 0-cryptoxanthin; 015 and 037, 014 for lycopene. Major dietary sources of -carotene and lutein plus zeaxanthin, mustard, turnip and collard greens; of beta-cryptoxanthin, orange juice; and of lycopene, tomato juice. CONCLUSIONS: On average, carotenoid intakes and serum concentrations are not lower in this southern African American population than the general US population. The two regional FFQs developed for a southern US population and used as dietary assessment tools in the JHS appear to provide reasonably valid information for most of these carotenoids.     

Sterol oxidation in ready-to-eat infant foods during storage

The effect of storage on sterol oxidation of ready-to-eat infant foods was evaluated. Two different liquid infant foods (honey or fruits flavors), prepared with milk and cereals, were stored for 0, 2, 4, 7 and 9 months at 25 degrees C. Sterol oxidation products (SOP) were isolated by cold saponification, purified by silica solid-phase extraction, and analyzed by gas chromatography (GC) and GC-mass spectrometry. beta-Sitosterol was the most representative sterol, followed by cholesterol and campesterol. No significant differences in the total and single SOP content (0.8-1 mg/kg of product) were observed with respect to storage time and type of sample; the main SOP found was 7-ketositosterol (<0.2 mg/kg of product). The extent of stigmasterol oxidation (2.9%) was higher than that of cholesterol (1.9%) and beta-sitosterol (1.4%). The type and quality of raw materials, as well as the processing conditions, seem to greatly influence SOP formation and accumulation in infant foods.     

Simulation of over-exploitation of ornamental fish and its consequences for the functional structure of assemblages of Amazonian streams

The consequences of over-exploitation may seriously impair the integrity and functioning of ecosystems. When loss of species is accompanied by the loss of ecological processes, the effects are no longer just taxonomic and may affect the stability of the environments. Ornamental fishing is one of the main economic activities of the middle Negro River. Such activity is directed to a small number of species and has the Cardinal Tetra (Paracheirodon axelrodi) as the main target species. Given the potential effects this pressure and the lack of information on its consequences, the present study analysed, through simulations, the possible effects of depletion of ornamental fish populations on the functional structure of fish assemblages, represented by functional diversity (FD) and functional redundancy (FR) indexes. We sampled 13 streams exploited by the ornamental fishery, where we collected 4,286 specimens of 110 species, of which 22 were targeted as ornamental fishing. We found that the ornamental species corresponded, on average, to 27.8% of the species and 33.3% of the FD of the assemblages. In a scenario of complete exclusion of ornamental species, local communities would lose 24.6% of the FD and reduce up to 12% of the FR. With these results, it is possible to infer that the local extinction of exploited species would cause negative impacts on the multifunctionality and the resilience of the streams ecosystems. In this way, we emphasise the need for proper management of the ornamental fisheries aiming to the sustainability of the activity and to the conservation of ecosystem functionality.