The red imported fire ants, Solenopsis invicta （Buren）, are generally considered pests. They have also been viewed as beneficial predators feeding on other insect pests of various agroecosystems. This study document...The red imported fire ants, Solenopsis invicta （Buren）, are generally considered pests. They have also been viewed as beneficial predators feeding on other insect pests of various agroecosystems. This study documents the foraging habits of fire ants in a sweetpotato field in Mississippi. Fire ant foraging trails connecting outside colonies to a sweetpotato field were exposed and foraging ants moving out of the field toward the direction of the colony were collected along with the solid food particles they were carrying. The food material was classified as arthropod or plant in origin. The arthropod particles were identified to orders. Fire ant foragers carried more arthropods than plant material. Coleoptera and Homoptera were the most abundant groups preyed upon. These insect orders contain various economically important pests of sweetpotato. Other major hexapod groups included the orders Hemiptera, Diptera and Collembola. The quantity of foraged material varied over the season. No damage to sweetpotato roots could be attributed to fire ant feeding. Imported fire ant foraging may reduce the number of insect pests in sweetpotato fields.展开更多
Ecosystem health and sustainability,to a large degree,depend on the performance of keystone or dominant species.The role of climate on population dynamics of such species has been extensively examined,especially for h...Ecosystem health and sustainability,to a large degree,depend on the performance of keystone or dominant species.The role of climate on population dynamics of such species has been extensively examined,especially for health indicator species.Yet the life-cycle processes and response lags for many species could complicate efforts to detect clear climate signals.Longleaf pine(Pinus palustris Mill.)is such a keystone tree species in the southeastern United States that has declined in both abundance and distribu-tion during the past century.Despite research efforts on multiple fronts,the mechanisms behind the large spatial and temporal fluctuations in cone production that affects its regeneration are largely unknown.On the basis of long-term(15-56 yr)monitoring data at 10 sites across the species’native range,we examine the spatial and temporal patterns in cone production and possible climatic effects on those patterns using the information-theoretic approach.Cone production exhibited great variation across sites and years,and long-term data revealed a weak,ca.3 yr cycle(4 in one case)across the native range.The effects of climate were rather complex,most likely due to a mismatch between the prolonged cone-production life cycle process and climatic fluctuation.Spatially,sites close to each other generally showed similar physical conditions and temporal trends in cone production.Across sites within longleaf pine’s range,moderate climate conditions appear to promote cone production.At most sites,there was an increasing trend in cone production,but how such a trend might be linked to climate change requires further investigation.展开更多
Human activities and global change have resulted in more severe and destructive megafires in forest ecosystems worldwide.Here,I introduce and discuss the concept of“management mosaics”and how to use it over both spa...Human activities and global change have resulted in more severe and destructive megafires in forest ecosystems worldwide.Here,I introduce and discuss the concept of“management mosaics”and how to use it over both space and time to mitigate the growing impacts of extreme wildfires.展开更多
基金北京林业大学研究生自选课题基金资助项目(06jj038)中美碳联盟USCCC国际合作资助项目美国宇航局项目“Effects of Land Use Change on The Energy and Water Balance of The Semi-Arid Region of Inner Mongolia”
文摘The red imported fire ants, Solenopsis invicta （Buren）, are generally considered pests. They have also been viewed as beneficial predators feeding on other insect pests of various agroecosystems. This study documents the foraging habits of fire ants in a sweetpotato field in Mississippi. Fire ant foraging trails connecting outside colonies to a sweetpotato field were exposed and foraging ants moving out of the field toward the direction of the colony were collected along with the solid food particles they were carrying. The food material was classified as arthropod or plant in origin. The arthropod particles were identified to orders. Fire ant foragers carried more arthropods than plant material. Coleoptera and Homoptera were the most abundant groups preyed upon. These insect orders contain various economically important pests of sweetpotato. Other major hexapod groups included the orders Hemiptera, Diptera and Collembola. The quantity of foraged material varied over the season. No damage to sweetpotato roots could be attributed to fire ant feeding. Imported fire ant foraging may reduce the number of insect pests in sweetpotato fields.
基金supported by USDA National Institute of Food and Agriculture McIntire Stennis project(1008643).
文摘Ecosystem health and sustainability,to a large degree,depend on the performance of keystone or dominant species.The role of climate on population dynamics of such species has been extensively examined,especially for health indicator species.Yet the life-cycle processes and response lags for many species could complicate efforts to detect clear climate signals.Longleaf pine(Pinus palustris Mill.)is such a keystone tree species in the southeastern United States that has declined in both abundance and distribu-tion during the past century.Despite research efforts on multiple fronts,the mechanisms behind the large spatial and temporal fluctuations in cone production that affects its regeneration are largely unknown.On the basis of long-term(15-56 yr)monitoring data at 10 sites across the species’native range,we examine the spatial and temporal patterns in cone production and possible climatic effects on those patterns using the information-theoretic approach.Cone production exhibited great variation across sites and years,and long-term data revealed a weak,ca.3 yr cycle(4 in one case)across the native range.The effects of climate were rather complex,most likely due to a mismatch between the prolonged cone-production life cycle process and climatic fluctuation.Spatially,sites close to each other generally showed similar physical conditions and temporal trends in cone production.Across sites within longleaf pine’s range,moderate climate conditions appear to promote cone production.At most sites,there was an increasing trend in cone production,but how such a trend might be linked to climate change requires further investigation.
文摘Human activities and global change have resulted in more severe and destructive megafires in forest ecosystems worldwide.Here,I introduce and discuss the concept of“management mosaics”and how to use it over both space and time to mitigate the growing impacts of extreme wildfires.
