Raymond B. Iglay

Deer Carrying Capacity in Mid‐Rotation Pine Plantations of Mississippi

Abstract Herbicides, commonly used for vegetation management in intensively managed pine (Pinus spp.) forests of the southeastern United States, with and without fire, may alter availability of quality forage for white-tailed deer (Odocoileus virginianus; deer), an economically and socially important game species in North America. Because greater forage quality yields greater deer growth and productivity and intensively managed pine forests are common in the southeastern United States, forest managers would benefit from an understanding of fire and herbicide effects on forage availability to improve habitat conditions for deer. Therefore, we evaluated independent and combined effects of fire and herbicide (i.e., imazapyr) on forage biomass and deer nutritional carrying capacity (CC) on land owned and managed by Weyerhaeuser NR Company in east-central Mississippi, USA. We used a randomized complete block design of 6 pine plantations (blocks) divided into 4 10-ha treatment plots to each of which we randomly assigned a treatment (burn-only, herbicide-only, burn + herbicide, and control). We estimated biomass (kg/ha) of moderate- and high-use deer forage plants during July of 1999–2008, then estimated CC for diets to support either body maintenance (6% crude protein) or lactation (14% crude protein) with a nutritional constraints model. Herbaceous forages responded positively to fire and herbicide application. In most years, CC estimates for maintenance and lactation were greater in burn + herbicide than in controls. Maintenance-level CC was always greater in burn + herbicide than in controls, except at 1 year posttreatment. Burn + herbicide was 2.6–8.3 times greater (x ¯  =  4.0) than control for lactation-level CC in 8 of 9 years posttreatment. We recommend fire and selective herbicides to increase high-quality deer forage in mid-rotation, intensively managed pine plantations.

Multiple paternities increase genetic diversity of offspring in Brandt's voles.

Mating system and philopatry influence the genetic structure of a social group in mammals. Brandts vole (Lasiopodomys brandtii) lives in social groups year-round and has male biased dispersal, which makes the vole a model system for studies of genetic consequences of mating system and philopatry. This study aimed to test the hypotheses that: (1) multiple paternity (MP) would exist in Brandts voles, enhance offspring genetic diversity and reduce genetic relatedness between littermates; (2) promiscuity would occur in this species in that males and females mate with multiple partners; and (3) plural breeders of a social group would be genetically related because of philopatry of female juveniles in Brandts voles. Paternity analysis indicated that MP occurred in 11 (46%) of 24 social groups examined and that promiscuity existed in this species. Multiple paternity litters had twice the offspring genetic diversity and half the average within-litter genetic relatedness of single paternity litters. We also found plural breeding females in six social groups. Average pairwise genetic relatedness of plural breeders ranged from 0.41 to 0.72 in four social groups, suggesting first-order kinship. Future studies need to investigate effects of reproductive skew and MP on population genetic structure of Brandts voles.

Large Mammal Use of Seminatural Grasslands and Implications for Aviation Strike Risk

Abstract Large mammals pose a significant risk to U.S. aircraft safety within airport operation areas and cost airlines millions of dollars in repairs annually. Native warm-season grass polycultures and switchgrass monocultures offer alternative land covers for airports that could benefit current risk-mitigation efforts in addition to offering economic and environmental benefits. We compared use of a native warm-season grass polyculture and switchgrass Panicum virgatum monoculture by white-tailed deer (deer; Odocoileus virginianus) and coyote Canis latrans, using remote cameras in Mississippi, during 2011–2012. Coyotes and deer were observed 27% and 51% less in switchgrass monoculture than in native warm-season grass polyculture, respectively. However, November detections and cumulative hazard score demonstrated the greatest differences between treatments, especially for deer. Considering deer and coyotes are among the most hazardous mammal species to aircraft, switchgrass monocultures could be a better a...

Soil N and C Response to Mid-Rotation Vegetation Management in Intensively Managed Pine Stands

Abstract Long-term sustainability of intensively managed forests depends on historical management and inherent soil productivity. However, long-term effects of prescribed fire and herbicide on forest floor and soil C and N pools are poorly understood, whereas benefits to biodiversity are well supported. Therefore, we investigated forest floor and mineral soil C and N responses to factorial combinations of mid-rotation dormant season prescribed fire and imazapyr herbicide (Arsenal®) in intensively managed mid-rotation pine (Pinus species) stands in east-central Mississippi. We used a randomized complete block design of six pine stands, each containing four 10-ha treatment plots receiving one of three treatments (herbicide only, prescribed fire only, both herbicide and fire) and a control at random. We applied herbicide via skidder in fall 1999 and prescribed fires using drip torches in winter, 2000, 2003, and 2006. During winter 2009, we sampled substrate using soil cores, a hammer core, and a fixed-area sampling frame for forest floor samples. Prescribed fire, with or without herbicide, reduced forest floor total N. However, C:N was only greater in burn + herbicide plots than controls, with independent treatments intermediate to treatment extremes. Considering the minimal effects of fire and herbicide use on soil nutrients and observed biodiversity benefits from these practices, prescribed fire with or without imazapyr herbicide does not seem to negatively impact long-term sustainability within similar managed pine landscapes of the southeastern United States.