Thesis (M.A.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 23, 2007) Includes bibliographical references.

In the greater Central Hardwood Region, advance regeneration of oak (Quercus spp.) and hickory (Carya spp.) has been in decline for several decades. Facilitated in part by an abrupt change in disturbance regime, coupled with an increase in herbivore density, the existing mid-successional, mast-producing species are being outcompeted by late-successional, mesophytic species. Oak-hickory forests provide keystone resources for a diverse forest wildlife community, and a decline in its dominance will likely impact habitat use and occupancy patterns in the mammal community, but to what extent is unclear. During May-August 2015-2016, I deployed 150 remotely-triggered camera traps in Trail of Tears State Forest (TTSF), Union County, Illinois to investigate single-season, site occupancy patterns and detection probabilities as a function of forest composition and structure for 3 mammals (eastern gray squirrel [Sciurus carolinensis], raccoon [Procyon lotor], and white-tailed deer [Odocoileus virginianus]). I collected microhabitat data at each camera-site and utilized a GIS application to estimate spatial relationships among anthropogenic features and camera-sites. I recorded 404 photographs of 11 endothermic species during 3927 days of survey effort, with white-tailed deer, raccoons, and eastern gray squirrels as the most detected species, respectively. Detection probability of eastern gray squirrels was best explained by the global detection model, indicating no covariate measured explained the variation in detection rates. Raccoon detection probability was best described by a negative relationship with the average temperature recorded during survey period. The best-fitting detection model for white-tailed deer indicated detection probabilities declined throughout the sampling period and across seasons. Eastern gray squirrel site occupancy models received little support, however, ecological land type phase was the most supported model. The best fitting habitat model described a negative relationship between eastern gray squirrel site occupancy probability and coarse woody debris volume. For raccoons, no model with habitat covariates was better fitting than the null model. Raccoon occupancy probability increased with maximum DBH at a site, ground cover, and beech-maple importance values, but decreased with oak-hickory importance values. White-tailed deer occupancy was most positively influenced by ground cover and oak-hickory importance values, but decreased with distance to forest edge, number of understory stems, and beech-maple importance values. My research provides empirical evidence to predictions made regarding the impact of a decline in oak dominance across the Central Hardwood region on a portion of the region’s mammal community. Shifts to late-successional conditions in the Central Hardwood region will likely continue and magnify if forest management approaches continue to minimize the frequency and occurrence of large, anthropogenic disturbances to the forest overstory. A mosaic of forest conditions will be needed to best support a diverse and complete mammal community across the region.

For the last 9,000-10,000 years the Central Hardwood Region (CHR) has been primarily composed of a mosaic of mesophytic communities in climax and communities of successional forest types dominated by oak (Quercus Linnaeus) and hickory (Carya Nuttall). Shade intolerant oak/hickory dominated forest types have been maintained by natural disturbance processes in synergy with anthropogenic causes, resulting in a large composition of communities which are neither at climatic nor edaphic climax. Reduction in fire events, thinning, forest grazing, and other disturbance processes over the last 80-100 years have coincided with decreased regeneration of shade intolerant species due to lack of adequate light availability and recruitment of shade tolerant species of communities dominated by American beech (Fagus grandifolia L.) and maple (Acer saccharum L.) into the overstory of forests typically dominated by oak/hickory. Forest inventory data at Trail of Tears State Forest was analyzed across two separate time events (1980 and 2014) to determine compositional and structural changes which have occurred. Density, basal area, and community patterns via ordination were compared across six Ecological Land Types (ELTs) to determine topography’s effect on composition. Community trends were analyzed via NMS Ordination and between ELTs by a Mantel Test. A Multi-Response Permutation Procedures (MRRP) was also used as a nonparametric method for assessing differences between ELTs examined in the NMS. Density and basal area between years for species, ELT, and species*ELT interactions were compared. Across all ELTs, between 1980 and 2014, overstory density decreased from 218 trees/ac in 1980 to 180 trees/ac in 2014 and basal area increased from 98 ft2/ac in 1980 to 106 ft2/ac in 2014. Maple basal area increased from 5 ft2/ac to 12 ft2/ac while beech increased from 1 ft2/ac to 8ft2/ac, signifying progression of these species from the understory up into the canopy. The component of soft masting species within the forest has also decreased sharply in the last 34 years. MRPP analysis of overstory compositional gradients reported distinct species compositions between ELTs, however the trend was weak (MRPP: p < 0.001, A = 0.038). NMDS ordination graphs confirmed MRPP showing little separation among ELTs. The final stress was 18.71146 and instability was < 0.01 after 212 iterations (Table 6). Our research at TTSF is a clear example of oak/hickory succession to beech maple on an upland site among species community types as delineated by topographic moisture gradient (ELTs) within the CHR. Expansion of beech and maple onto xeric ELTs suggests a breakdown of edaphic barriers that have previously been thought to be resistant to encroachment from mesophytic species. Currently oak decline induced by lack of management is likely the number one forest health issue resulting in loss of oak/hickory and other soft masting species.