Charles Kwit

University of Tennessee | UTK · Department of ​Forestry, Wildlife & Fisheries

While the reassembly of fruit‐frugivore interactions remains at the forefront of tropical forest restoration, seed dispersal networks emerge as a potential approach to enhance restoration success. This review explores the integration of seed dispersal networks in tropical forest restoration, with the aims of (1) synthesizing important findings in t...

The putative benefits to seeds in myrmecochory (ant‐mediated seed dispersal) are often cast in a reward context. However, microbes have been mostly overlooked as seed mortality agents in myrmecochory, as have potential treatments provided by ant‐handling. We investigated the effects of ant handling on the diversity of seed coat fungal communities o...

Aim Abiotic, biotic and dispersal factors interact to shape species distributions. At broad geographic extents, abiotic factors are thought to exert the greatest influence on the distribution, while biotic and dispersal factors strongly influence the distribution regionally and locally. We test whether reproductive traits relating to biotic and dis...

Background In oak-dominated communities throughout eastern North America, fire exclusion and subsequent woody encroachment has replaced the “glitter” of once robust and diverse wildflower and grass layers with leaf-litter dominance. Restoring the important herbaceous components of Eastern oak ecosystems could involve pairing heavy canopy disturbanc...

Myrmecochory is a widespread mutualism in which plants benefit from seed dispersal services by ants. Ants might also be providing seeds with an additional byproduct benefit via reduced plant pathogen loads in the ant nest environment through their antimicrobial glandular secretions. We investigate this byproduct benefit by identifying fungal commun...

Abstract Morphological and chemical attributes of diaspores in myrmecochorous plants have been shown to affect seed dispersal by ants, but the relative importance of these attributes in determining seed attractiveness and dispersal success is poorly understood. We explored whether differences in diaspore morphology, elaiosome fatty acids, or elaios...

Questions A paradoxical co‐existence challenges woodland and savanna restoration worldwide: How are shade‐intolerant, flammable herbaceous layers promoted while maintaining the shade‐casting, more fire‐sensitive woody regeneration that sustains overstorey structure? Where restoration success consisted of robust, diverse herbaceous layers and vigoro...

Abstract— Fire exclusion in oak-dominated communities of the Appalachian and Central Hardwood regions of eastern North America (hereafter, Mid-South) has reduced herbaceous groundcover and diversity. Restoring these important community components could involve pairing heavy canopy-disturbance and growing-season fire. Beginning with 20-ha replicates...

As insect pollinator populations continue to decline, it is essential to understand the impacts of anthropogenic activities, including forest management, on pollinator communities. Although multiple studies have shown that clearcutting is beneficial for bees, other less intense, selective silvicultural methods that result in disproportionate increa...

Mesophication has reduced fuel-bed flammability in the Mid-Southern US, limiting the effectiveness of fire alone in promoting disturbance-adapted woody species. We applied combinations of thinning (none, 7, and 14 m² ha–1 residual basal area) and seasonal fire (none, October, and March) at three sites and monitored understory woody response from 20...

Premise of the Study Comparing ecological attributes of endemic species with related, widespread species can reveal differences accounting for rarity. Forests of the southeastern United States are home to many range‐restricted endemic and widespread species of Trillium, a genus of ant‐dispersed herbs. Evidence suggests that aspects of seed‐related...

Thinning and burning can restore imperilled oak woodlands and savannas in the Southern Appalachian and Central Hardwood regions of the USA, but concomitant effects on fuels are less understood. We monitored (2008 to 2016) fuel load response to replicated combinations of thinning (none, 7, and 14 m² ha⁻¹ residual basal area) and seasonal fire (none,...

Extended abstract—The eastern oak (Quercus) forest ecosystem once included extensive open-canopy and early successional communities (i.e., woodlands and savannahs) that had been maintained by frequent natural and anthropogenic fires (Burhans et al. 2016). However, beginning in the early Twentieth Century and continuing until the present, fire regim...

Background Switchgrass is C4 perennial grass species that is being developed as a cellulosic bioenergy feedstock. It is wind-pollinated and considered to be an obligate outcrosser. Genetic engineering has been used to alter cell walls for more facile bioprocessing and biofuel yield. Gene flow from transgenic cultivars would likely be of regulatory...

Studies addressing the benefits of “directed dispersal” in ant seed dispersal systems have highlighted the beneficial soil properties of the nests of ants that disperse their seeds. No studies, however, have explored the properties of soils nearby exemplary seed-dispersing ant nests, where recent work indicates that seeds are quickly “redispersed”...

Myrmecochory is typically cast as a mutualistic relationship in which seed dispersal of plants with elaiosome-bearing seeds is performed by ants. Benefits of this mutualism may seem simple at first: ants gain a nutritive reward via elaiosomes, while plant propagules gain protection and a more suitable microsite for establishment and growth. However...

Thresholds in herbaceous response to canopy disturbance level on the Cumberland Plateau, TN

The agricultural landscape of the United States could soon be changed by planting of switchgrass (Panicum virgatum L.) cultivars to meet government-mandated targets for lignocellulosic bioenergy production and consumption. This alteration could affect the genetic structure of wild switchgrass populations, which are native to the eastern half of Nor...

Background/Question/Methods Myrmecochory is the mutualistic relationship between plants and the ant species that disperse their seeds. The plants involved in a myrmecochorous relationship produce seeds that contain a fleshy appendage called an elaiosome. Chemicals that constitute elaiosomes encourage ants to carry diaspores to their nests, where...

Background/Question/Methods Conservation organizations understandably prioritize their efforts towards ‘species of concern.’ Attention is often focused on species designated as ‘threatened’ and ‘endangered’ at national levels, along with knowledge of their spatial status. We assessed vulnerability to climate change for Tennessee’s 22 federally-li...

Genetically engineered (GE) ringspot virus-resistant papayas cultivars 'Rainbow' and 'SunUp' have been grown in Hawai'i for over 10 years. In Hawai'i, the introduction of GE papayas into regions where non-GE cultivars are grown and where feral non-GE papayas exist have been accompanied with concerns associated with transgene flow. Of particular con...

Weighing contrasting evidence is an integral element of science (Osborne 2010). The dominant forum for doing this and for scientific exchange in general is the peer-review and publication process. It tends to be slow because of the time required to conduct critical reviews. Rapid exchange and discourse, in the form of a live debate, can also move s...

Switchgrass (Panicum virgatum L.) is a C4 perennial warm season grass indigenous to the North American tallgrass prairie. A number of its natural and agronomic traits, including adaptation to a wide geographical distribution, low nutrient requirements and production costs, high water use efficiency, high biomass potential, ease of harvesting, and p...

Background/Question/Methods Disturbances beyond a threshold of intensity or frequency can initiate or maintain early successional vegetation. Throughout the southern Appalachian mountains and more broadly the eastern U.S., disturbances, including fire, wind storms, and landslides, interweave with complex topography and vegetation history to produc...

Importance of Assessment and Detection of Gene Flow Detection Methodologies Applications in Assessment of Gene Flow Perspectives Acknowledgments References

ABSTRACT Fleshy fruit is a key food resource for many vertebrates and may be particularly important energy source to birds during fall migration and winter. Hence, land managers should know how fruit availability varies among forest types, seasons, and years. We quantified fleshy fruit abundance monthly for 9 years (1995-2003) in 56 0.1-ha plots in...

The advantages of ant-mediated seed dispersal for myrmecochorous plants have often been framed in the context of directed dispersal and predator avoidance. Underlying and intertwining themes in these frameworks are the services of (a) moving seeds away from parent plants, (b) placing seeds in safe and ideal locations and occasionally, (c) removing...

Panicum virgatum L. (switchgrass) is an obligate outcrossing C4 perennial prairie grass currently being pursued for the production of lignocellulosic ethanol. Commercial production of switchgrass for bioenergy has increased substantially in the United States. Understanding the degree of native genetic diversity within and among switchgrass populati...

There currently exists a large push for the use, improvement, and expansion via landscape modification of dedicated biofuel crops (feedstocks) in the United States and in many parts of the world. Ecological concerns have been voiced because many biofuel feedstocks exhibit characteristics associated with invasiveness, and due to potential negative c...

Different disturbances in similar habitats can produce unique successional assemblages of plants. We collected plant species composition and cover data to investigate the effects of three common types of disturbances—fire, anthropogenic clearing ('cleared'), and clearing followed by goat grazing ('cleared‐and‐grazed')—on early‐successional coppice...

Background/Question/Methods Forest vertical structure and disturbance history affect woody species composition and avian habitat. Remote sensing of forest vertical structure is possible with lidar data, but lidar data are not widely and freely available. Landsat time series allow mapping of forest disturbance dates, but this process can be diffic...

Incorporation of crop genes into wild and weedy relative populations (i.e. introgression) has long been of interest to ecologists and weed scientists. Potential negative outcomes that result from crop transgene introgression (e.g. extinction of native wild relative populations; invasive spread by wild or weedy hosts) have not been documented, and f...

We mapped tropical dry forest height (RMSE = 0.9 m, R2 = 0.84, range 0.6-7 m) and foliage height profiles with a time series of gap-filled Landsat and Advanced Land Imager (ALI) imagery for the island of Eleuthera, The Bahamas. We also mapped disturbance type and age with decision tree classification of the image time series. Having mapped these va...

Remote sensing of forest vertical structure is possible with lidar data, but lidar is not widely available. Here we map tropical dry forest height (RMSE = 0.9 m, R2 = 0.84, range 0.6–7 m), and we map foliage height profiles, with a time series of Landsat and Advanced Land Imager (ALI) imagery on the island of Eleuthera, The Bahamas, substituting ti...

Background/Question/Methods Fundamentally different disturbances in similar habitats should produce unique successional assemblages of plants. We collected plant species composition data to investigate the effects of three common disturbances–fire, clearing (i.e., bulldozing), and clearing followed by goat grazing (‘cleared-and-grazed’)–on the veg...

To characterize the nonbreeding habitat of Kirtland's Warbler (Dendroica kirtlandii) on Eleuthera, The Bahamas, we quantified the habitat at sites where we captured the warblers and compared these traits with those of random sites and sites of tall coppice. On the basis of a chronosequence of satellite imagery, 153 capture sites ranged in age from...

Durante un período de siete años realizamos censos invernales, en cinco ambientes diferentes, de dos migrantes de corta distancia, Catharus guttatus y Dendroica coronata, para determinar si las abundancias locales pueden ser predichas a partir de la biomasa de pulpa de fruto. Los ambientes muestreados fueron plantaciones de especies de madera dura...

Size and age structures of stand populations of numerous tree species exhibit uneven or reverse J-distributions that can persist after non-catastrophic disturbance, especially windstorms. Among disjunct populations of conspecific trees, alternative distributions are also possible and may be attributed to more localized variation in disturbance. Reg...

Capped waste sites often are vegetated with commercial turf grasses to increase evapotranspiration and prevent erosion and possible exposure of the barrier. Fertilizer, frequent watering, and mowing may be required to establish the turf grass and prevent invasion by trees and shrubs. Oldfield vegetation of grasses and forbs is a possible sustainabl...

This chapter illustrates using simulations how the assumed Janzen-Connell relationship between distance from parent and seed density can break down. Emphasis is given on spatial patterns of seed dispersal, the resultant spatial structure of seeds and the potential consequences for the population and the community. A special form of dispersal limita...

We examined long-term impacts of mammalian herbivores and canopy gap characteristics on woody plant establishment and growth within six size classes of canopy gaps created in 1994 in a southern bottomland hardwood forest. Woody stem composition (1996, 2004) and height (2004) were assessed in and out of white-tailed deer (Odocoileus virginianus) and...

2004. Contagious seed dispersal beneath heterospecific fruiting trees and its consequences. Á/ Oikos 107: 303 Á/308. An hypothesized advantage of seed dispersal is avoidance of high per capita mortality (i.e. density-dependent mortality) associated with dense populations of seeds and seedlings beneath parent trees. This hypothesis, inherent in near...

Although land preservation and promotion of successful regeneration are important conservation actions, their ability to increase population growth rates of slow-growing, long-lived trees is limited. We investigated the demography of Taxus floridana Nutt., a rare understory conifer, in three populations in different ravine forests spanning its enti...

We tested the hypothesis that winter removal rates of fruits of wax myrtle, Myrica cerifera, are higher in colder winters. Over a 9-year period, we monitored M. cerifera fruit crops in 13 0.1-ha study plots in South Carolina, U.S.A. Peak ripeness occurred in November, whereas peak removal occurred in the coldest months, December and January. Mean t...

We conducted winter censuses of two short-distance migrants, Hermit Thrushes (Catharus guttatus) and Yellow-rumped Warblers (Dendroica coronata), over seven years in five different habitats to determine whether their local abundances could be predicted by fruit pulp biomass. Sampled habitats were stands of upland and bottomland hardwood, loblolly p...

Is regeneration of understory trees in closed-canopy forests following large-scale disturbances influenced by the recent history of small-scale disturbances? We ex-amined recruitment (in-growth of advance recruits to 2-cm diameter at 1.5-m height at each biennial census), growth, and mortality of non-pioneer understory trees in local areas with dif...

After Hurricane Andrew crossed southern Florida (U.S.A.) on 24 August 1992, native and exotic pioneer species in subtropical hardwood forests (hammocks) regenerated from seed banks. Regeneration occurred in hammocks of metropolitan Dade County and the Long Pine Key region of Everglades National Park. The density of the native pioneer Trema micranth...

Steephead ravine forests of the Apalachicola River Bluffs region of northern Florida contain tree species that are widespread in the Southeastern Coastal Plain and species that are highly endemic, such as the Florida yew, Taxus floridana. We sampled woody vegetation in three ravine systems within the Apalachicola Bluffs and Ravines Preserve (Libert...