Data from: Effect of pyric herbivory on source-sink dynamics in grassland birds

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.