Riparian zones of channelized agricultural streams in northwestern Mississippi typically consist of narrow vegetative corridors low in habitat diversity and lacking riparian wetlands. Land clearing practices and strea...Riparian zones of channelized agricultural streams in northwestern Mississippi typically consist of narrow vegetative corridors low in habitat diversity and lacking riparian wetlands. Land clearing practices and stream channelization have led to the development of gully erosion and further fragmentation of these degraded riparian zones. Currently, installation of a gully erosion control structure (drop pipe) at the riparian zone-agricultural field interface leads to the incidental establishment of four riparian habitat types that differ in habitat area, vegetative structure, and pool size. Small mammals were sampled within four sites of each habitat type from June 1994 to July 1995. Small mammal diversity, abundance, and hispid cotton rat (Sigmodon hispidus) weight were the least within smallest Type I habitats with the least vegetative structural diversity and were the greatest within the larger Type II, III, or IV habitats having greater vegetative structural diversity and pool size. Small mammal diversity and abundance were the least in the summer 1994, increased in the fall 1994, and then declined later in our study. Hispid cotton rat abundance was the least in summer 1994, winter 1994, and spring 1995 and was the greatest in fall 1994 and summer 1995. Our results suggest that modifying the drop pipe installation design to facilitate the development of larger riparian habitats with greater vegetative structural diversity will provide the greatest benefits for small mammals.展开更多
Outdoor education programs frequently offer stream classes that teach students how to assess water quality based on the composition of aquatic macroinvertebrate communities. Repeatedly using the same site for stream c...Outdoor education programs frequently offer stream classes that teach students how to assess water quality based on the composition of aquatic macroinvertebrate communities. Repeatedly using the same site for stream classes can cause disturbance that could negatively impact aquatic macroinvertebrates. However, the impact of outdoor education stream classes on short term temporal trends of aquatic macroinvertebrates has not been evaluated. Our objective was to quantify whether outdoor education stream classes caused localized and short-term impacts on the aquatic macroinvertebrate community. We sampled aquatic macroinvertebrates over a five day period in May 2014 from an impacted riffle subjected to repeated substrate disturbance by outdoor education stream classes and an unimpacted riffle that was not subjected to stream classes within an agricultural stream in central Ohio. We did not observe a difference in macroinvertebrate community response variables between different time periods or among days within the impacted riffle as part of our within riffle analysis. We documented that macroinvertebrate abundance and dorsoventrally flattened clinger abundance was greater within the unimpacted riffle than the impacted riffle. Macroinvertebrate evenness was greater in the impacted riffle than the unimpacted riffle. In the impacted riffle percent clingers was greater on Monday than on Friday. Conversely, in the unimpacted riffle percent clingers was greater on Friday than on Monday. Our results indicated that outdoor education stream classes did not alter short term temporal trends of macroinvertebrate community structure within an impacted riffle, but the stream classes resulted in differences in community structure between an impacted and unimpacted riffle. Our results suggest that outdoor education centers should avoid repeatedly using the same site for their stream classes to prevent negatively impacting aquatic macroinvertebrates.展开更多
Conservation practices are encouraged to improve soil health and sustain agronomic crop production.Mehlich-3 is often used as a multi-nutrient extractant to determine soil fertility status.A study inves-tigated the im...Conservation practices are encouraged to improve soil health and sustain agronomic crop production.Mehlich-3 is often used as a multi-nutrient extractant to determine soil fertility status.A study inves-tigated the impacts of the conservation practices of gypsum,cover crops,and crop rotation on 28 Mehlich-3 extractable elements,of which 11 were considered plant nutrients,from soil at three mid-western US locations.Soil was collected from 0 to 15 and 15-30 cm depths 5 years after implementing the conservation practices.Treatments consisted of(1)with and without cereal rye(Secale cereale L.)winter cover,(2)continuous soybean[Glycine max(L.)Merr.]vs.soybean-corn(Zea mays L.)rotation,and(3)annual gypsum application(0,1.1,and 2.2 Mg ha-1).Differences were observed by site,depth,and conservation practice depending on the element evaluated.Minimal interactive effects were observed among treatments.The most consistent effect was observed for crop rotation across sites.Gypsum only affected the site with the greatest clay content,where more Ca and S were retained,and Mg and Mn displaced.Cover crop only affected elements at this high clay site,where different elements were positively or negatively affected.Results suggest that not one practice fits all,and optimum conservation practices must be tailored for the site.展开更多
文摘Riparian zones of channelized agricultural streams in northwestern Mississippi typically consist of narrow vegetative corridors low in habitat diversity and lacking riparian wetlands. Land clearing practices and stream channelization have led to the development of gully erosion and further fragmentation of these degraded riparian zones. Currently, installation of a gully erosion control structure (drop pipe) at the riparian zone-agricultural field interface leads to the incidental establishment of four riparian habitat types that differ in habitat area, vegetative structure, and pool size. Small mammals were sampled within four sites of each habitat type from June 1994 to July 1995. Small mammal diversity, abundance, and hispid cotton rat (Sigmodon hispidus) weight were the least within smallest Type I habitats with the least vegetative structural diversity and were the greatest within the larger Type II, III, or IV habitats having greater vegetative structural diversity and pool size. Small mammal diversity and abundance were the least in the summer 1994, increased in the fall 1994, and then declined later in our study. Hispid cotton rat abundance was the least in summer 1994, winter 1994, and spring 1995 and was the greatest in fall 1994 and summer 1995. Our results suggest that modifying the drop pipe installation design to facilitate the development of larger riparian habitats with greater vegetative structural diversity will provide the greatest benefits for small mammals.
文摘Outdoor education programs frequently offer stream classes that teach students how to assess water quality based on the composition of aquatic macroinvertebrate communities. Repeatedly using the same site for stream classes can cause disturbance that could negatively impact aquatic macroinvertebrates. However, the impact of outdoor education stream classes on short term temporal trends of aquatic macroinvertebrates has not been evaluated. Our objective was to quantify whether outdoor education stream classes caused localized and short-term impacts on the aquatic macroinvertebrate community. We sampled aquatic macroinvertebrates over a five day period in May 2014 from an impacted riffle subjected to repeated substrate disturbance by outdoor education stream classes and an unimpacted riffle that was not subjected to stream classes within an agricultural stream in central Ohio. We did not observe a difference in macroinvertebrate community response variables between different time periods or among days within the impacted riffle as part of our within riffle analysis. We documented that macroinvertebrate abundance and dorsoventrally flattened clinger abundance was greater within the unimpacted riffle than the impacted riffle. Macroinvertebrate evenness was greater in the impacted riffle than the unimpacted riffle. In the impacted riffle percent clingers was greater on Monday than on Friday. Conversely, in the unimpacted riffle percent clingers was greater on Friday than on Monday. Our results indicated that outdoor education stream classes did not alter short term temporal trends of macroinvertebrate community structure within an impacted riffle, but the stream classes resulted in differences in community structure between an impacted and unimpacted riffle. Our results suggest that outdoor education centers should avoid repeatedly using the same site for their stream classes to prevent negatively impacting aquatic macroinvertebrates.
基金support provided by United Soybean Board Project Number 1520-732-7226by state and federal funds appropriated to The Ohio State University and The Ohio Agricultural Research and Development Center。
文摘Conservation practices are encouraged to improve soil health and sustain agronomic crop production.Mehlich-3 is often used as a multi-nutrient extractant to determine soil fertility status.A study inves-tigated the impacts of the conservation practices of gypsum,cover crops,and crop rotation on 28 Mehlich-3 extractable elements,of which 11 were considered plant nutrients,from soil at three mid-western US locations.Soil was collected from 0 to 15 and 15-30 cm depths 5 years after implementing the conservation practices.Treatments consisted of(1)with and without cereal rye(Secale cereale L.)winter cover,(2)continuous soybean[Glycine max(L.)Merr.]vs.soybean-corn(Zea mays L.)rotation,and(3)annual gypsum application(0,1.1,and 2.2 Mg ha-1).Differences were observed by site,depth,and conservation practice depending on the element evaluated.Minimal interactive effects were observed among treatments.The most consistent effect was observed for crop rotation across sites.Gypsum only affected the site with the greatest clay content,where more Ca and S were retained,and Mg and Mn displaced.Cover crop only affected elements at this high clay site,where different elements were positively or negatively affected.Results suggest that not one practice fits all,and optimum conservation practices must be tailored for the site.
