Grassland bird populations are sharply declining in North America. Changes in agricultural practices during the past 50 years have been suggested as one of the major causes of this decline. Field-border conservation practices encouraged by the U.S. Department of Agriculture's National Conservation Buffer Initiative meet many of the needs of sustainable agriculture and offer excellent opportunities to enhance local grassland bird populations within intensive agricultural production systems. Despite the abundant information on avian use of, and reproductive success in, strip habitats during the breeding season, few studies have examined the potential value of field borders for wintering birds. We planted 89.0 km of field borders (6.1 m wide) along agricultural field edges on one-half of each of three row crop and forage production farms in northeastern Mississippi. We sampled bird communities along these field edges during February-March 2002 and 2003 using line-transect distance sampling and strip transects to estimate density and community structure, respectively. We used Program DISTANCE to estimate densities of Song (Melospiza melodia). Savannah (Passerculus sandwichensis), and other sparrows along bordered and non-bordered transects while controlling for adjacent plant community. Greater densities of several sparrow species were observed along most bordered transects. However, effects of field borders differed by species and adjacent plant community types. Diversity, species richness, and relative conservation value (a weighted index derived by multiplying species-specific abundances by their respective Partners in Flight conservation priority scores) were similar between bordered and non-bordered edges. Field borders are practical conservation tools that can be used to accrue multiple environmental benefits and enhance wintering farmland bird populations. Provision of wintering habitat at southern latitudes may influence population trajectories of short-distance migrants of regional conservation concern.

Potential opportunity costs of conservation buffer practices were examined to determine the effects of proximity to field edge and adjacent plant community (APC) type (crop, herbaceous, and wooded) on crop yields, relative to field interiors for corn (Zea mays) and soybean (Glycine max) systems on 150 fields in Mississippi. Yield data were obtained from combines equipped with a yield monitor and Global Position System (GPS) for years 1999‐2003 for three counties in central Mississippi. A partial budget format was used to develop net change in profit analyses on corn and soybean crops with and without conservation practice CP‐33: Habitat Buffers for Upland Birds. Yield reductions averaged across three APC types at swath 1 (defined as one 7.32‐m‐wide combine header pass) were ‐2,963 kg/ha and ‐230 kg/ha compared to mean interior yields of 9,828 kg/ha and 2,498 kg/ha for corn and soybeans, respectively. Partial budget analyses for corn showed that on average, enrollment of a 7.32‐m (36‐ft) CP‐33 border would increase net returns when next to APC‐type crop, herbaceous, and wood.

The genesis of this study is in response to the United States (US) Fish and Wildlife Service (USFWS) listing of the monarch butterfly (Danaus plexippus plexippus) on 17 December 2020 in the US Federal Register as a candidate species under the Endangered Species Act of 1973. Annual censuses have identified that the eastern and western North American monarch migratory populations have been generally declining over the last 20 yr due to a myriad of environmental factors. Monarch reproduction at the larval stage is dependent on the presence of milkweed (Asclepias) plant species. The United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS) National Resource Inventory rangeland data set (~23,400 on-site samples; 2032 sites with milkweed presence) was used to evaluate milkweed species densities, geolocations, and environmental gradients. Twenty-two milkweed species were identified on rangelands across 17 sampled US western states, with seven species comprising 65.5% of milkweed frequency of occurrence. The most dominant milkweed species on non-federal rangelands were Asclepias viridis, A. syriaca, A. verticillata, and A. speciosa (constancy >10% where milkweed was present). Asclepias speciosa was the dominant species from the standpoint of total plant density for the data set, whereas A. viridis was the most frequently occurring species. Total milkweed density estimates based on low, midpoint, and high estimates were 1.3, 4.1, and 6.9 B plants on 13.2 M ha. Seven US states

No abstract

Habranthus tubispathus (L’Hér.) Traub is reported as new to the flora of Mississippi, U.S.A.