Data from: Effect of pyric herbivory on source-sink dynamics in grassland birds
Davis, Craig A. et al. (2017), Data from: Effect of pyric herbivory on source-sink dynamics in grassland birds, Dryad, Dataset, https://doi.org/10.5061/dryad.2pn59
Grasslands world-wide provide a host of ecosystem services. In particular, these grasslands serve as biodiversity repositories for a myriad of imperilled animal species. One such group is grassland birds, which have experienced significant declines, predominantly caused by extensive loss and degradation of native grasslands. Rangeland management that promotes increasing and sustaining livestock production through reducing the inherent, disturbance-driven variability that historically occurred in grasslands is considered a major contributing factor to these declines. An alternative approach to this homogeneous management paradigm attempts to restore a shifting mosaic of disturbance patches across the landscape through the spatial and temporal interactions of fire and grazing (i.e. pyric herbivory). Application of pyric herbivory through patch-burn grazing increases overall habitat heterogeneity, likely a critically important factor in maintaining and enhancing grassland bird populations. We compared reproductive rates and estimates of fecundity of three grassland birds nesting in grasslands maintained by traditional and patch-burn grazing management paradigms in the Southern Great Plains of North America. Additionally, we used a sensitivity analysis approach to assess population stability (i.e. λ = 1) and source–sink population dynamics under the two management practices. Nest survival for dickcissels Spiza americana and grasshopper sparrows Ammodramus savannarum was higher in patch-burned grasslands than in traditionally managed grasslands, while nest survival for eastern meadowlarks Sturnella magna was higher in traditionally managed grasslands than in patch-burned grasslands. Dickcissels and grasshopper sparrows responded positively to patch burning with source habitats occurring over a wider range of survival rates under patch burning than traditional management, while no clear pattern emerged in source–sink dynamics of eastern meadowlarks. Synthesis and applications. Management strategies such as patch-burn grazing offer opportunities to restore landscape heterogeneity to benefit bird communities while maintaining livestock production goals. Applying patch-burn grazing to rangelands can increase productivity of grassland birds and could be effective for reversing the decline of grassland birds by providing source habitats more consistently than traditional rangeland management. Our results emphasize the utility of using sensitivity analyses to determine source–sink population dynamics when evaluating management practices. However, land managers should consider that source–sink models have shortcomings and designation of a habitat as a sink does not necessarily mean the habitat has low conservation value.
36o50’ N 96o25’ W
Tallgrass Prairie Preserve