Patch-burn grazing provides resources for upland-nesting ducks

. Contemporary rangeland management has expanded from a focus on forage and livestock production to multi-use management practices that include concepts like biodiversity and natural disturbance regimes. Patch-burn grazing (PBG) has been promoted as a multi-use land management practice that can restore vegetation structural heterogeneity and subsequently increase diversity of higher trophic levels, such as grassland birds. However, little is known about how the diverse assemblage of upland-nesting ducks responds to disturbances like interacting fire and grazing within a PBG framework. PBG divides a pasture into equal proportions (i.e., patches) and burns an individual patch annually to reduce residual vegetation and attract livestock grazing. Upland-nesting ducks are generally thought to require dense vegetation structure associated with areas of low disturbance for nesting. However, prescribed fire and grazing are essential for the conservation and management of grasslands. PBG may negatively affect ducks in recently burned patches, but may also support ducks through the provisioning of greater structure in patches with greater year(s) since fire (YSF) and could be a viable management strategy to meet grassland and duck conservation objectives. To assess the compatibility of PBG with duck conservation, we estimated nest site selection and survival of duck nests on private lands managed with PBG in the unglaciated plains and prairie pothole region of North Dakota, USA. We located 478 duck nests of four species: 230 Blue-winged Teal (Spatula discors), 72 Gadwall (Mareca strepera), 71 Mallard (Anas platyrhynchos), and 105 Northern Pintail (A. acuta). Blue-winged Teal, Gadwall, and Mallard selected for ??? 2 YSF and avoided ??? 1 YSF patches. Northern Pintail selected for 1 YSF and 2 YSF patches. Year (s) since fire affected survival differently for Blue-winged Teal and Gadwall, indicating the importance of variable structure resulting from disturbance regimes. Additionally, nest survival decreased as litter accumulation increased for Blue-winged Teal and Gadwall. Our findings indicate that PBG created nesting areas for ducks in later YSF patches. However, we found contrasting effects of survival in selected patches for certain species. High selection but low survival was limited to a single patch and does not necessarily limit duck nesting activity with adjacent patches having high selection and survival. Additional management strategies may be required to ensure > 1 YSF patch consists of vegetation characteristics that will attract duck nesting activity. Given our results, it appears that variable structure resulting from PBG is in line with conservation objectives, and given the need for multi-objective management, this may be a good choice for land managers interested in game and non-game conservation goals.