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White-tailed Deer: Dispersers or Predators of American Ginseng Seeds?
Abstract and Figures
As a result of game management practices and alterations in habitat, white-tailed deer populations (Odocoileus virginianus Z.) have increased to all time highs within the last century. Large herd numbers are having negative impacts at multiple levels in forest ecosystems, although there are many aspects that have not yet been investigated. One of the least understood impacts is the effect of deer browsing on the fate of valuable harvested understory species such as American ginseng (Panax quinquefolius L.). The objectives of this study were to quantify the natural frequency at which fruit-bearing ginseng plants are browsed by deer, to determine the amount of ginseng seeds consumed by deer and with feeding trials, to determine if white-tailed deer are seed dispersers or seed predators of American ginseng. Our results showed that fruits are frequently browsed in natural populations and that browsed seeds are most likely destroyed during the digestive process. The loss of ginseng seeds to deer browsing can negatively impact the seed bank and ultimately affect long term population growth and viability. Although white-tailed deer and American ginseng are managed species, effective growth of deer populations is adversely affecting ginseng, as well as other valuable forest species.
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... 89,95,96,98,103,104 Several studies have documented the effects of deer browsing on American ginseng. [57][58][59]105 White-tailed deer may be exacerbating the rarity of ginseng, as herbivory, within some populations, occurs at high rates and deer are seed predators of ginseng. 105 Though human harvesters and deer both remove plant tissue, harvesters remove the root, which results in death of the plant, and they may (or may not) plant seeds to encourage reproduction. ...
... [57][58][59]105 White-tailed deer may be exacerbating the rarity of ginseng, as herbivory, within some populations, occurs at high rates and deer are seed predators of ginseng. 105 Though human harvesters and deer both remove plant tissue, harvesters remove the root, which results in death of the plant, and they may (or may not) plant seeds to encourage reproduction. Deer effects are likewise variable, but generally affect only aboveground plant parts: deer may remove a portion or all of the leaves, reproductive structures and stalk (Fig. 6), but typically leave the root intact. ...
... Deer may also hinder new recruitment in a population by consuming fruits, since seeds are destroyed during the digestive process. 105 Deer browsing affects the size distribution and fertility of plants in a population. In studying browse rates and patterns of browse in natural and experimental ginseng populations, Furedi 57 found that plant characteristics and microsite conditions related to apparency influence browse susceptibility. ...
American ginseng (Panax quinquefolius L.) is an uncommon to rare understory plant of the eastern deciduous forest. Harvesting to supply the Asian traditional medicine market made ginseng North America's most harvested wild plant for two centuries, eventually prompting a listing on CITES Appendix II. The prominence of this representative understory plant has led to its use as a phytometer to better understand how environmental changes are affecting many lesser-known species that constitute the diverse temperate flora of eastern North America. We review recent scientific findings concerning this remarkable phytometer species, identifying factors through its history of direct and indirect interactions with humans that have led to the current condition of the species. Harvest, deer browse, and climate change effects have been studied in detail, and all represent unique interacting threats to ginseng's long-term persistence. Finally, we synthesize our current understanding by portraying ginseng's existence in thousands of small populations, precariously poised to either escape or be drawn further toward extinction by the actions of our own species.
... In addition to herbivorous insects, large herbivores can be a major problem for ginseng leaves and stems. For example, white-tailed deer (Odocoileus virginianus) can completely browse the above-ground parts of 50% or more of P. quinquefolius plants in the wild [39]. However, there have been no studies to determine if ginsenosides have antifeedant activity against large herbivores. ...
Ginsenosides are saponins that possess a sugar moiety attached to a hydrophobic aglycone triterpenoid. They have been widely studied for their various medicinal benefits, such as their neuroprotective and anti-cancer activities, but their role in the biology of ginseng plants has been much less widely documented. In the wild, ginsengs are slow-growing perennials with roots that can survive for approximately 30 years; thus, they need to defend themselves against many potential biotic stresses over many decades. Biotic stresses would be a major natural selection pressure and may at least partially explain why ginseng roots expend considerable resources in order to accumulate relatively large amounts of ginsenosides. Ginsenosides may provide ginseng with antimicrobial activity against pathogens, antifeedant activity against insects and other herbivores, and allelopathic activity against other plants. In addition, the interaction of ginseng with pathogenic and non-pathogenic microorganisms and their elicitors may trigger increases in different root ginsenosides and associated gene expression, although some pathogens may be able to suppress this behavior. While not covered in this review, ginsenosides also have roles in ginseng development and abiotic stress tolerance. This review shows that there is considerable evidence supporting ginsenosides as important elements of ginseng’s defense against a variety of biotic stresses.
... Similarly, Canada mayflower (Maianthemum canadense) was 40 times less likely to flower when exposed to deer browse (Cote et al. 2004). Furedi and McGraw (2004) found that deer eliminated more than half of all fruit-bearing American ginseng plants from West Virginia forests and consumed 50 to 100% of all seeds in some populations. As a result of deer browse and intense wild harvest pressures, this and other economically valuable Appalachian medicinal herbs may be driven to extinction in the coming century. ...
The Virginia landscape supports a remarkable diversity of forests, from maritime dune woodlands, swamp forests, and pine savannas of the Atlantic Coastal Plain, to post-agricultural pine-hardwood forests of the Piedmont, to mixed oak, mesophytic, northern hardwood, and high elevation spruce-fir forests across three mountain provinces in western parts of the state. Virginia's forests also have been profoundly shaped by disturbance. Chestnut blight, hemlock woolly adelgid, emerald ash borer, and other pests have caused declines or functional extirpation of foundation species. Invasive plants like multiflora rose, Oriental bittersweet, and Japanese stiltgrass threaten both disturbed and intact forests. Oaks and other fire-dependent species have declined with prolonged fire suppression, encouraging compositional shifts to maple, beech, and other mesophytic species. Agriculture has left lasting impacts on soil and microsite variations, and atmospheric nitrogen deposition has led to soil acidification, nutrient loss, and diversity declines. Future changes associated with climate warming are expected to influence species distributions and habitat quality, particularly for hemlock-northern hardwood and spruce-fir forests. These and other disturbances will continue to shape Virginia's forests, influencing species interactions, successional trajectories, and susceptibility to invasive plants and secondary stressors, and initiating broader impacts on forest diversity, ecosystem processes, and habitat resources for associated species and neighboring ecosystems. DIVERSITY OF VIRGINIA'S FORESTS Biodiversity losses affect ecosystems throughout the world, but forests have been particularly affected. Like most forests in eastern North America, those in Virginia have undergone centuries of change, shaped by natural and cultural disturbances. Pollen records suggest that Appalachian oak forests have changed more rapidly over
... Using the data removal approach described above, McGraw and Furedi (2005) showed that virtually all ginseng populations have low population viability at current rates of deer browse, but would be viable with significant reductions in browse. Experimental studies confirmed that in addition to consuming leaf material, deer were ginseng seed predators, and not dispersers (Furedi and McGraw, 2004). Defoliation, especially early in the season, was shown to decrease plant size and reproductive output in ginseng (Furedi, 2004, Farrington et al., 2008. ...
Effects of high deer herbivory in North America on populations of favored plant browse species have been well-documented, however since less palatable plants now dominate the understory, we asked whether these species could be vulnerable as well, and if so, what symptoms might signal that this was occurring? Using American ginseng (Panax quinquefoliusL.) as our representative less palatable understory plant, we compared two subpopulations within a single natural population that were differentially exposed to browse; one isolated from deer by growing atop a large, flat-topped boulder, and a browse-exposed subpopulation in the surrounding low-lying area. We tested the hypothesis that deer effects would be manifested in all parts of the life history; through reduced growth, survival and reproduction. In turn, we hypothesized that browse would reduce population growth rates, and that differences in stage structure of the population would be produced. Taking advantage of a 20 year record of formal demographic censusing, we showed that browse effects were manifested primarily in reduced size-specific growth, while size-specific fertility and survival were relatively unaffected by exposure to browse. Demographically, these differences in growth were sufficient to drive population size reductions of 4.5%/y in the off rock subpopulation while the on rock plants slowly increased in number. High browse off the rock resulted in high proportions of plants in a stunted juvenile state in the off rock population relative to the on rock plants. A high proportion of juveniles is therefore a clear symptom of an understory subjected to chronic overbrowsing, providing land managers a rapid way to assess whether deer could be impacting understory biodiversity. The sharp demographic contrasts we observed between browsed and unbrowsed subpopulations also implies that promotion of refugia within managed lands will likely become increasingly important management tools for biodiversity preservation as long as unchecked deer populations persist.
... Much of the research concerning the effects of deer on plant communities have focused on their role as browsers and the potential for overbrowsing (Alverson and Waller 1997;Stromayer and Warren 1997;Royo et al. 2010). However, several studies have looked at the role of white-tailed deer as both seed predators and seed dispersers (Cambell and Gibson 2001;Vellend et al. 2003;Furedi and McGraw 2004;Myers et al. 2004; Bartuszevige and Endress 2008). Due to their large home-range size (e.g. ...
Mechanisms of long-distance dispersal are important in establishing and maintaining plant populations in isolated wetland habitats. White-tailed deer (Odocoileus virginianus) have been cited as long-distance dispersers of both native and exotic plant species in North America; however, knowledge regarding their influence in wetlands is limited. Given traditional classification methods for seed dispersal, white-tailed deer are not likely viewed as important dispersal mechanism for wetland plants. We collected naturally deposited white-tailed deer faecal pellet piles from wetlands in Canaan Valley, West Virginia, USA. Pellet piles were cold-stratified and germinated seedlings over a layer of sterile potting mix. The percentage of germinated seedlings with a facultative wetland (FACW) or obligate wetland (OBL) plant indicator status were compared to the frequency of occurrence to those of germinated plants with facultative upland (FACU) or upland (UPL) indicator status. We identified 38 species. Of these, 1 % were UPL, 38 % were FACU, 18 % were FACW and 21 % were OBL. Graminoid species accounted for 42 %; forbs and woody species accounted for 29 % each. Our research has suggested that endozoochory by herbivores contributes to long-distance dispersal of wetland plants.
... Knight et al. (2009) reported that deer target flowering stages of Trillium grandiflorum, which do not produce seed in the year they are browsed, and deer herbivory decreased reproductive values of T. grandiflorum plants in the largest three stage classes. Furedi and McGraw (2004) found that more than 50% of fruitbearing ginseng plants were browsed completely We found that the slope of regression equations through the origin was different than the one in 2006 (slope = 0.73 ± 0.011, t 8 = 2.432, p = 0.038), but not in 2005 (slope = 0.618 ± 0.262, t 6 = 1.458, p = 0.188) or 2007 (slope = 0.63 ± 0.21, t 7 = 1.75, p = 0.119; Figure 6). ...
White-tailed deer (Odocoileus virginianus Zimm.) may influence reproduction and dispersal of plant species through herbivory of flowering stems. We examined the effects of white-tailed deer herbivory on the seed production of Bog Jacob’s-ladder (Polemonium vanbruntiae Britt.), a facultative wetland plant considered rare throughout its range. We monitored life-stage transitions in 10 local populations in Canaan Valley, West Virginia, from 2005–2007, modeled the population growth rates, and estimated extinction rates for each population accounting for the loss of seeds due to white-tailed deer florivory. Seed loss due to consumption of flowering stems ranged between 0 and 96% within individual populations (
= 52 ± 4.5%). A significant difference in seed production occurred between browsed (
= 0.6 ± 0.18) and unbrowsed (
= 24 ± 1.43) plants. Predicted seed loss was significantly higher (
= 57 ± 19%), where no hunting was allowed, than where deer hunting occurred (
= 40 ± 18%). The observed levels of white-tailed deer florivory have the potential to significantly reduce population growth rates (p < 0.0001). Although white-tailed deer florivory may not increase local population extinction rates, loss of seed production may result in a loss of the potential for colonization of new patches.
American ginseng (Panax quinquefolius) is a globally desired medicinal plant that is becoming increasingly difficult to study due to harvest-induced rarity. Thus, this species' conservation could be greatly improved via species distribution models, making it a model organism for studying sampling bias. In an attempt to refine a state-derived distribution model for ginseng in Virginia, we conducted additional surveys in a biologically diverse yet under-sampled region of the statethe Cumberland Mountainsthereby increasing the number of documented ginseng occurrences in this region thirteen-fold (N1 = 16, N2 = 214). Our surveys resulted in the model predicting an increased probability of American ginseng occurrence not only statewide (1 = 0.099, 2 = 0.104) but particularly so in the Cumberland Mountains (1 = 0.170, 2 = 0.278), highlighting a consistently overlooked hotspot for biodiversity in Southern Appalachia. We suggest that more geographically balanced surveys and reduced overrepresentation of heavily protected and managed areas such as National Parksin addition to heeding local knowledgecan be an effective method of mitigating geographic bias in predictions from species distribution models.
Asian ginseng played an integral role in traditional Chinese medicine for millennia, but overexploitation of the plant, coupled with habitat loss, contributed to steep declines in natural populations throughout China. The discovery of the closely related medicinal herb, American ginseng, in Canada in the early 1700s ignited three centuries of trade between North America and China. Profits made from the export of American ginseng to China facilitated western expansion in the United States, and the fortunes of some early Americans were built on the American ginseng trade. American ginseng has been harvested continuously in North America following its initial discovery, punctuated by regional spurts of intense harvest in response to economic needs of rural residents. The ongoing extraction of American ginseng from deciduous forests throughout its range have resulted in modern populations that contain fewer individuals and individuals of smaller stature relative to historic populations, yet thousands of these remnant populations remain. In fact, concerns about overharvest of American ginseng led to its placement on Appendix II of the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES) in 1975. Overexploitation, however, is not the only threat to wild populations of American ginseng. Climate change and browse by overabundant white-tailed deer also negatively affect American ginseng and pose a threat to the future viability of populations. Conservation efforts are needed to ensure that populations of wild American ginseng persist. Population stewardship is a low-labor conservation strategy where individuals promote the growth of wild ginseng populations by strategically planting seeds and removing the aboveground portion of large plants just prior to the onset of harvest season to prevent potential harvesters from locating the adult plants. Another conservation strategy, conservation through cultivation, involves shifting harvest pressure from wild American ginseng to cultivated ginseng. Wild-simulated cultivation is a low-labor technique where seeds are planted into desirable habitat and are left to grow with little intervention until the roots are ready for harvest years later. Wild-simulated cultivation produces roots that are virtually indistinguishable from true wild roots, which makes this type of cultivation a desirable option for the conservation through cultivation approach. Additional cultivation techniques include woods-cultivation, which is ginseng grown in prepared beds under natural forest canopies, and artificial shade cultivation, which is the most labor-intensive cultivation technique and requires large initial investments in shade structures and site preparation. The last two cultivation techniques can produce large roots and abundant seeds in a short period of time. However, the roots lack morphological features desired in traditional Chinese medicine, and are less valuable than both wild-simulated and true wild roots. The abundance and size of wild American ginseng populations are decreasing range-wide, and this negative trajectory is certain to continue unless efforts are made to both improve the management of wild populations and to increase conservation efforts.
American ginseng (Panax quinquefolius) is an uncommon perennial understory herb found in eastern deciduous forest. The species is harvested for the international medicinal plant trade. While previous research has inferred that seed dispersal is limited, the production of bright red, fleshy berries suggests long-distance dispersal may be facilitated by songbirds. The objective of this study was to determine how songbirds interacted with ginseng and whether they dispersed or predated ginseng seeds. We used infrared, motion-activated cameras to observe animal—ginseng interactions in the field. To determine the disperser potential of songbirds observed visiting ginseng in the field, we conducted a captive feeding study at the Tennessee Aquarium. Thrushes removed berries from ginseng infructescences more frequently, compared to other potential dispersers, and regurgitated viable seeds 5–37 minutes after ingestion in feeding trials. By dispersing ginseng seeds, thrushes provide a mechanism for ginseng to improve its probability of persistence in the face of 3 primary threats to populations: deer browse, harvest, and climate change.
Here, we review evidence for the contention that chronically high densities of white-tailed deer are having multiple, and often substantial, deleterious ecological impacts across many regions. To structure this review, we specifically consider whether deer are acting as a 'keystone' herbivore to substantially alter ecological communities. We define a keystone species as one that: 1) affects the distribution or abundance of many other species, 2) can affect community structure by strongly modifying patterns of relative abundance among competing species, or 3) affects community structure by affecting the abundance of species at multiple trophic levels. Power et al. (1996) added that keystone species were expected to have disproportionately large impacts on communities. The concept of a keystone species was originally applied to a carnivores that affected the relative abundance and competive interactions among their prey; now, however, most ecologists accept the idea as pertaining to species on any tropic level. With this in mind, we briefly review past and current efforts to assess the nature and severity of the ecological impacts of deer. Considering our 3 criteria for a keystone species, we discuss the impacts of deer on tree seedlings (criteria 1 and 2 above), herbaceous plants (criteria 1 and 2), and species on higher trophic levels (criterion 3). While these data remain far from comprehensive, we conclude that ample evidence exists to publicly acknowledge the substantial risk posed by sustaining high deer densities. We therefore conclude by discussing the larger management issues these results raise.
[The authors] examined how woody and herbaceous plant frequency, cover, and overall species diversity have responded to regional variation, both historic and recent, in white-tailed deer densities in the Apostle Islands and nearby Wisconsin mainland. [They] observed lower frequencies of several woody species, including mountain maple (Acer spicatum), yellow birch (Betula alleghaniensis), and mountain-ash (Sorbus decora), in areas of high deer densities. Higher historic (1950s and 1960s) and recent (1980s and 1990s) estimated deer densities tended to depress the frequency of Canada yew (Taxus canadensis). The proportion of unbrowsed sugar maple (A. saccharum) twigs at a site also decreased predictably with deer density, as did the frequency of bluebead lily (Clintonia borealis). Frequencies of wild sarsaparilla (Aralia nudicaulis), Canada mayflower (Maianthemum canadense), and Clintonia borealis decreased in areas of historically high deer density. [The authors] also observed that herbaceous species richness and frequency and percent cover of C. borealis decreased with recent increases in deer density. Path analyses of C. borealis frequency and species richness suggest that deer have both immediate and persistent effects on herbaceous community structure. Population size and scape height in C. borealis may provide reliable and efficient indicators for the impact of deer on both common and rare herbaceous species.
In 1929, baseline vegetation data were collected in Heart's Content Scenic Area, an old-growth, 50-ha hemlock-northern hardwood tract within the Allegheny National Forest in northwestern Pennsylvania, USA. In 1995, we resampled the ground layer to document the extent of changes in the herb and shrub vegetation in this tract since 1929. We recorded changes in herb and shrub species frequency, abundance, richness, and evenness between 1929 and 1995. Numerous species present in 1929 were absent in 1995: 33 species (80%) were missing from the hemlock-beech stand, and 16 species (59%) were missing from the hemlock stand. More species were missing than were new in the hemlock-beech (sign test, p<0.0001) and in the hemlock stand (sign test, p=0.0001), and more species declined in abundance than increased (sign test p<0.0001) in the hemlock-beech stand. In both stands, species with relative abundance values of <1% in 1929 were more likely than more abundant species to be missing in 1995. Evenness of herbaceous species declined in the hemlock-beech stand but increased in the hemlock stand. High species richness at the quadrat scale was negatively associated with high densities of hay-scented fern (Dennstaedtia punctilobula Michx). The number of families represented declined from 27 in 1929 to 10 in 1995 (sign test, p=0.0001). We attribute declines in species richness to the direct and indirect effects of herbivory by white-tailed deer. We suggest that this tract can and should be restored using a management strategy that includes building a deer exclosure around the entire tract, reducing fern abundance, and reintroducing extirpated species.
In Central American deciduous forests, most of the seeds of the caesalpinaceous legume tree Cassia grandis are killed by the larvae of two bruchid beetles, Pygiopachymerus lineola and Zabrotes interstitialis. Pygiopachymerus lineola oviposits on the large pods, the first-instar larvae bore into the seeds, and the emerging adults cut large exit holes in the pod wall. Moth larvae gain access through these holes and eat clean much of the sticky pulp around the seeds. Simultaneously, the adults of Z. interstitialis enter through the P. lineola exit holes and oviposit directly on all clean seeds. In heavily disturbed communities where vertebrate dispersal agents are absent, these host-specific bruchids achieve almost 100% predation on the C. grandis seed crop; however, the more rapidly the dispersal agents remove the seed pods, the less seed predation there will be by Z. interstitialis. Since C. grandis bears mature fruit every other year, the size of each seed crop is large enough to surpass the predation abilities of the bruchids that survive the distance in time and space between seed crops. The system may be viewed as an example of predator satiation. The potential for further co-evolution of the bruchid-Cassia interaction is high, but numerous opposing forces in the selective process can be identified.
To assess the impact of white-tailed deer (Odocoileus virginianus) on endangered and threatened flora, [the authors] reviewed pertinent literature and conducted a telephone survey of professional botanists, endangered species scientists, natural area managers, and U.S. National Park Service resource managers. Ninety-eight species of threatened or endangered plants were reported disturbed by deer. Monocots and dicots comprised 39.8% and 56.1%, respectively, of the species disturbed. Of the disturbed species, 38.7% belong to families Liliaceae and Orchidaceae.
Both defoliation and higher leaf placement can reduce growth in herbaceous plants. We examined variation in relative growth rate (RGR) and reproduction in response to defoliation and leaf height in Trillium grandiflorum at 4 sites in northern Wisconsin, USA. Plant biomass and the probability of flowering increased with increased leaf height. Analyses of covariance revealed that experimental defoliation and leaf height separately and independently reduced individual RGR, and accounted for about 42% of the total variance in RGR. Defoliation in 1998 had no effect on flowering in 1999, but leaf height in 1998 was positively associated with the likelihood of flowering in 1999. RGR and plant responses to defoliation varied among sites. We conclude that defoliation and leaf height reduce RGR over short time scales.
The height of white-flowered trillium (Trillium grandiflorum) is a useful indicator of deer browsing intensity. In their foraging activities deer select larger plants over smaller plants. Because flowering plants are larger than nonflowering plants, the number of plants in flower decreases with increasing browsing intensity. As browsing intensity increases, the height of the Trillium becomes shorter in successive growing seasons, presumably due to the loss of photosynthetic capacity and reduction in belowground resources. Tillium stem height was positively correlated with reproductive output by perennial herbaceous plants and negatively correlated with the percent of the herbaceous understory that is browsed. This indicates change in stem height is an indication of the general status of the herbaceous flora as influenced by deer browsing. Based on deer population densities associated with study sites supporting Trillium populations with stable stem heights and flowering plants, maintenance of deer densities of 4-6 individuals/km(2) is recommended for deciduous forests in northeastern Illinois. In eastern United States, research workers who assume they are studying relatively undisturbed sites should be aware that intense deer browsing may have imposed an alteration on their study sites.
A statewide study of Panax quinquefolium L. (American ginseng), a herb commonly collected for commercial sale, was conducted on 33 protected and unprotected forested sites in the northern, central and southern sections of Illinois. Within these sites, data on the tree, sapling, seedling, shrub and herbaceous strata, and on soil texture and nutrients were collected from a 0.05-ha circular plot in each site. Additional recorded site data included aspect, slope position, steepness and exposure, and disturbance from grazing or timber harvesting. Populations of Panax quinquefolium were found in stands dominated by Acer saccharum, Quercus alba or Q. rubra and with a variety of other herbaceous species common to cool, moist site conditions; 84% of the sites were located on NW-, N- and NE-facing slopes and 80% were in mid- to low-slope positions. Phenological events began in early May and progressed from S-N; plants were dormant by mid-October. Seeds from individuals growing on several sites within each region were planted at the time of leaf senescence. Seedlings did not appear until the 2nd spring; 66% of the seeds produced seedlings. An anatomical and morphological study of 30 whole field-collected plants indicated that plant age could be accurately determined by counting bud scale scars on the rhizome. These data were used to develop a multiple regression model to predict rhizome age from stern height and number of leaflets. For 30 field-collected and 65 forest-cultivated roots, average weight increased linearly up to age 20, the age of the oldest roots. Population age structure and fruit production on protected sites were compared with that of sites where roots had been removed by collectors. We found fewer plants of all ages on unprotected sites. Fruit production was lower on unprotected sites because fewer 5- to 11-yr-old plants limit fruit production and rate of population recovery after harvesting.
White-tailed deer (Odocoileus virginianus) populations have been maintained at high densities in Pennsylvania for several decades with unknown effects on songbirds and their habitats. I evaluated effects of white-tailed deer density on songbird species richness, abundance, and habitat. I simulated 4 deer densities (3.7, 7.9, 14.9, and 24.9 deer/km2) within individually fenced enclosures on 465-ha forest areas in northwestern Pennsylvania. Within all enclosures, 10% of the area was clear-cut and 30% was thinned. Enclosures were subjected to 10 years of deer browsing, 1980-90, at the 4 simulated densities. I conducted bird counts in 1991. Varying deer density had no effect (P > 0.1) on ground- or upper canopy-nesting songbirds or their habitat, but species richness of intermediate canopy-nesting songbirds declined 27% (P = 0.01) and abundance declined 37% (P = 0.002) between lowest and highest deer densities. I did not observe the eastern wood pewee (Contopus virens), indigo bunting (Passerina cyanea), least flycatcher (Empidonax minimus), yellow-billed cuckoo (Coccyzus americanus), or cerulean warbler (Dendroica cerulea) at densities >7.9 deer/km2, and the eastern phoebe (Sayornis phoebe), and American robin (Turdus migratorius) were not observed at 24.9 deer/km2. Threshold deer density for effect on habitat and songbirds within managed (100-yr rotation) forests was between 7.9 and 14.9 deer/km2.