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Grassland birds in North America have declined sharply over the last 60 years, driven by the widespread loss and degradation of grassland habitats. Climate change is occurring more rapidly in grasslands relative to some other ecosystems, and exposure to extreme and novel climate conditions may affect grassland bird ecology and demographics. To determine the potential effects of weather and climate variability on grassland birds, we conducted a systematic review of relationships between temperature and precipitation and demographic responses in grassland bird species of North America. Based on 124 independent studies, we used a vote‐counting approach to quantify the frequency and direction of significant effects of weather and climate variability on grassland birds. Grassland birds tended to experience positive and negative effects of higher temperatures and altered precipitation. Moderate, sustained increases in mean temperature and precipitation benefitted some species, but extreme heat, drought, and heavy rainfall often reduced abundance and nest success. These patterns varied among climate regions, temporal scales of temperature and precipitation (<1 or ≥1 month), and taxa. The sensitivity of grassland bird populations to extreme weather and altered climate variability will likely be mediated by regional climates, interaction with other stressors, life‐history strategies of various species, and species' tolerances for novel climate conditions. [ABSTRACT FROM AUTHOR]

Tall fescue (Schedonorus arundinaceus) is a widespread invasive grass in the United States that degrades habitat quality for biodiversity. Herbicide followed by seeding of native plants reduces tall fescue and is predicted to restore habitat quality over time, but little is known about short‐term (1–2 year) impacts on native species. We conducted a landscape‐scale controlled experiment to assess the short‐term effects of herbicide and seeding on the reproduction of an obligate grassland bird, the dickcissel (Spiza americana). In 2014, four sites in southern Iowa were each subdivided into three patches (mean 7 ha). One patch in each site was treated with glyphosate herbicide (spray‐only), one with herbicide and native seeding (spray‐and‐seed), with the third serving as a control. Two sites were grazed by cattle from April to July and two sites were ungrazed. We monitored dickcissel reproduction in 2016, finding that they were more abundant, built more nests, experienced less cowbird parasitism, had increased nest survival, and produced more fledglings on spray‐only and spray‐and‐seed treatments compared to control patches. Dickcissels nested infrequently on grazed sites—especially grazed control patches. We did not detect any impacts on clutch size, provisioning rates, or nestling mass, but Araneae (spiders) and Lepidoptera larvae (caterpillars) may have been smaller on sprayed patches. Positive responses by dickcissels were likely due to successful reduction of tall fescue and improved access to suitable nest sites through increased vegetation heterogeneity. Our results indicate that using herbicide and seeding to restore tall fescue‐dominated sites improves habitat quality for this grassland bird, shortly after restoration. [ABSTRACT FROM AUTHOR]

Tall fescue (Festuca arundinacea) is a Eurasian forage grass extensively planted in the United States. However, an endophytic fungus in tall fescue, Epichloë coenophiala, causes health problems in cattle. We predicted that cattle prefer to graze alternative forages when available. We also predicted that cattle use tall fescue more intensively in recently burned areas, as fire can increase forage quality. We tested these predictions in four diverse‐forage pastures in Iowa, comparing use by cattle of tall fescue and four alternative forages (non‐fescue cool‐season grasses, native warm‐season grasses, non‐leguminous forbs and legumes) to their availabilities at the pasture scale. We also examined how tall fescue influences the distribution of grazing at a fine scale (0.1‐m2 quadrats). Tall fescue was the most abundant forage (46% of plants), but composed only 26% of grazed vegetation. In contrast, legumes composed 12% of available forage but 25% of grazed vegetation. Other forages were used in proportion to availability. At a fine scale, total grazing frequency (proportion of plants grazed) was lower in quadrats containing abundant tall fescue, and higher in quadrats with abundant warm‐season grasses. Grazing frequency of tall fescue and other cool‐season grasses was greatest in recently burned quadrats, but total grazing frequency did not increase after burning. Our results show that although cattle graze tall fescue, particularly following burns, they limit their use of this grass. Given that tall fescue is underused, creates health risks for cattle, and degrades wildlife habitat quality, it may be advisable to reduce tall fescue in pastures. [ABSTRACT FROM AUTHOR]