Effects of prescribed fire and selective herbicide (Imazapyr) on biodiversity in intensively managed pine stands of Mississippi

Prescribed fire and imazapyr are two silviculture tools used to control hardwood midstory competition in intensively managed, mid-rotation pine (Pinus spp.) stands but also may support conservation of biodiversity in the southeastern United States. Therefore, I investigated select measures of biodiversity response, small mammals, reptiles, amphibians, carabid beetles, songbirds, and vegetation communities, to fire and imazapyr treatments in intensively managed, mid-rotation pine stands of east-central Mississippi. I used a randomized complete block design of 6 stands (blocks) with 4, 10- ha treatment plots assigned randomly a treatment of burn only, herbicide only, burn + herbicide, or control. I applied dormant season prescribed fires every 3 years beginning in January 2000 and a one-time application of imazapyr in September 1999 using 877 ml/ha (12.0 liquid oz./ac; Arsenal®, BASF 2006). I sampled avifauna, herpetofauna, small mammal, and carabid beetle communities using appropriate sampling techniques for attaining species-specific relative abundance. I also measured vegetation structure and biomass. Vegetation and bird communities exhibited significant responses to treatments. Imazapyr had the greatest initial impact on communities followed by a long-term effect of repeated prescribed fires on a 3 year fire-return interval. Combining fire and imazapyr perpetuated high-quality browse for white-tailed deer (Odocoileus virginianus), plant species richness, high-priority bird species relative abundances, and diversity of landscape-level vegetation structure and biomass by creating a two-tier vegetation structure (pine canopy and herbaceous understory). Independent treatments also were more effective management approaches to sustain biodiversity than controls by maintaining or increasing overall species richness specifically soon after treatment application. Most responses of other wildlife communities were time-limited suggesting the possibility of greater effects of factors other than treatments such as long-term disturbance regimes (e.g., forest management practices, climate trends), proximity of treatment plots to wetlands, and landscape-level population dynamics including characteristics within and among stands. Combined and independent applications of these treatments will support biodiversity conservation, sustainable forestry objectives, and concomitant timber management goals. Long-term conservation of biodiversity within an intensive timber management matrix also may benefit from future investigations of multiple-herbicide tank mixtures, population dynamics of indicator species, and landscape-level biodiversity responses across multiple strata

Effects of prescribed fire and selective herbicide (Imazapyr) on biodiversity in intensively managed pine stands of Mississippi

Prescribed fire and imazapyr are two silviculture tools used to control hardwood midstory competition in intensively managed, mid-rotation pine (Pinus spp.) stands but also may support conservation of biodiversity in the southeastern United States. Therefore, I investigated select measures of biodiversity response, small mammals, reptiles, amphibians, carabid beetles, songbirds, and vegetation communities, to fire and imazapyr treatments in intensively managed, mid-rotation pine stands of east-central Mississippi. I used a randomized complete block design of 6 stands (blocks) with 4, 10- ha treatment plots assigned randomly a treatment of burn only, herbicide only, burn + herbicide, or control. I applied dormant season prescribed fires every 3 years beginning in January 2000 and a one-time application of imazapyr in September 1999 using 877 ml/ha (12.0 liquid oz./ac; Arsenal®, BASF 2006). I sampled avifauna, herpetofauna, small mammal, and carabid beetle communities using appropriate sampling techniques for attaining species-specific relative abundance. I also measured vegetation structure and biomass. Vegetation and bird communities exhibited significant responses to treatments. Imazapyr had the greatest initial impact on communities followed by a long-term effect of repeated prescribed fires on a 3 year fire-return interval. Combining fire and imazapyr perpetuated high-quality browse for white-tailed deer (Odocoileus virginianus), plant species richness, high-priority bird species relative abundances, and diversity of landscape-level vegetation structure and biomass by creating a two-tier vegetation structure (pine canopy and herbaceous understory). Independent treatments also were more effective management approaches to sustain biodiversity than controls by maintaining or increasing overall species richness specifically soon after treatment application. Most responses of other wildlife communities were time-limited suggesting the possibility of greater effects of factors other than treatments such as long-term disturbance regimes (e.g., forest management practices, climate trends), proximity of treatment plots to wetlands, and landscape-level population dynamics including characteristics within and among stands. Combined and independent applications of these treatments will support biodiversity conservation, sustainable forestry objectives, and concomitant timber management goals. Long-term conservation of biodiversity within an intensive timber management matrix also may benefit from future investigations of multiple-herbicide tank mixtures, population dynamics of indicator species, and landscape-level biodiversity responses across multiple strata

Effects Of Prescribed Burning And Herbicide (Imazapyr) On The Abundance And Diversity Of Selected Invertebrate Communities In Thinned Pine Plantations Of Mississippi

Prescribed fire and herbicides are 2 silviculture tools used by forest managers to control hardwood competition in pine (Pinus spp.) forests. I tested effects of prescribed burning and herbicides on selected invertebrate communities, including carabid beetles, and compared 2 invertebrate sampling approaches in thinned, intensively managed pine stands in Kemper County, Mississippi. I used 6 replicate stands containing 4, 10-ha treatment plots each that were randomly assigned treatments of burn only, herbicide only, burn/herbicide, and control. I suction-sampled invertebrate communities and pitfall trapped carabid beetles to examine treatment responses. Direct effects of burning and overall vegetation response influenced communities most but responses were limited. Sampling inefficiencies may have obscured treatment effects and managers and researchers are advised to consider all available methods when integrating invertebrate research. Information on forest management effects is still lacking but future research incorporating invertebrate sampling will support a better understanding of management impacts on ecosystems

Bird use of grain fields and implications for habitat management at airports

Airport properties often include agricultural land cover that can attract wildlife species hazardous to aircraft, despite recommendations against row crops near air operations areas. However, few studies have directly quantified bird use of corn, wheat, and soybean fields relative to bird-aircraft collision (strike) hazard levels to support land cover recommendations. Therefore, we compared bird use among corn, wheat and soybean fields and predicted that corn and wheat would attract bird species recognized as hazardous to aviation. We also anticipated that soybeans would pose minimal attraction to such birds. Here, hazard ranking (low to extremely high) reflects the percentage of strikes involving a species that resulted in damage to aircraft. We investigated bird use among 22 corn, wheat, and soybean fields near Oak Harbor, OH, using approximately weekly point transects from 2013 to 2014. We used generalized distance sampling models and analysis of variance using distance matrices to determine bird abundance and community responses to row crop land coverages and crop height. We observed 4331 birds of 40 species, with most birds observed in wheat fields (n =2555 birds) and standing stubble (n= 2409 birds). Large flocks occurred more in corn and wheat fields than soybean fields, but soybean fields harbored greater cumulative hazard scores than corn, likely due to consistent detections of small, non-flocking birds in soybean fields. Crop type and height had greater influence on medium- and high-hazard level bird species than other hazard levels. Density of medium- and high-hazard level birds increased with increasing crop height in soybean and wheat fields with wheat fields having slightly greater densities than soybeans. Corn fields also had the greatest bird densities in the tallest crop height categories. Categories of very and extremely high-hazard level bird species were rarely detected, but their abundance peaked in crops 0–15 cm, similar to low-hazard level bird species. However, model selection results included null models for very and extremely high-hazard level bird species suggesting minimal effects. Overall, our results suggest that all three crop types can harbor birds hazardous to aircraft, and crop height can enhance bird use. Although not directly tested in our study, land management surrounding airports may benefit most from alternative land covers (e.g., biofuel crops), but additional research is necessary