Natural recovery from fire disturbance is more favorable than assisted recovery for the restoration of soil nematode-trapping fungi.

A fire is usually considered a severe disturbance factor in the environment. Globally, rising temperatures and increasing human activities have intensified the severity and frequency of fire incidents, and research on post-fire recovery has inevitably become an important focus for ecologists. In terms of the restoration of burned areas, there are usually two primary approaches: natural recovery and assisted recovery. However, very few relevant studies have systematically compared these recovery alternatives, suggesting which one is more favorable to the overall restoration of an ecosystem, especially to the soil microbes that function as indispensable components of ecosystems. In this study, the restoration of soil nematode-trapping fungi (NTF) in natural and assisted recovery environments was compared. The results showed that although the NTF community structures differed among the sample sites, the counts and diversity of the NTF communities in the upper and lower soil layers in the natural recovery area were higher than those in the assisted recovery and unburned control areas. These findings suggest that artificial efforts to help ecosystem recovery after fire negatively affect the speed and quality of soil NTF community recovery. Instead, natural recovery appears to be a more suitable land management choice after fire disturbance.

Trends in nasopharyngeal carcinoma mortality in China, 1973-2005.

Nasopharyngeal carcinoma (NPC) is a disease with distinct ethnic and geographic distribution. The incidence of NPC in Chinese residing in Asia has declined over the last few decades, but NPC mortality trends in the entire Chinese population over time have not been systematically evaluated. In this study, we examined NPC mortality at the national level in China between 1973-2005. Mortality rates were derived from the databases of national retrospective surveys on cancer mortality conducted in the periods of 1973-1975, 1990-1992, and 2004-2005, respectively. NPC was classified according to the International classification of diseases. Age-adjusted mortality rates were calculated by direct standardization according to the world standard population. Trends in rates were evaluated by age, gender, geographic areas, and socioeconomic status. From 1973 to 2005, there was a general trend of decrease in NPC mortality in China, with higher rates in the south on a downward trend in the north. The age-standardized NPC mortality rates were 2.60 per 100,000 in 1973-1975, 1.94 per 100,000 in 1990-1992, and 1.30 per 100,000 in 2004-2005, respectively. The trend was similar in both men and women, in both urban and rural areas, but the declining rates in females were more remarkable than in males. The mortality rates were higher for the age groups above 50 years than those less than 50 years of age, both showing downward trend over 30-year period. In summary, the overall NPC mortality has consistently decreased in China over the past three decades, particularly in women and in old adults.