Deer Resistance in Perennials

Factors That Contribute to Deer Resistance in Perennials

Deer resistance in perennials can be influenced by various factors, as indicated by the provided information. These factors include chemical repellents, fertilization, plant associations, morphological and physiological traits, and phylogenetic diversity.ref.19.136 ref.51.153 ref.41.22

1. Chemical repellents: One method to deter deer browsing is through the topical application of chemical repellents. Chemical compounds such as sulfur, selenium, and bittering agents have been found to be effective in repelling deer for short periods of time, ranging from days to months.ref.31.10 These repellents can act as deterrents by making the plants less palatable to deer, thereby reducing the likelihood of browsing.ref.31.10 ref.31.10 ref.31.10

Chemical repellents work to make plants less palatable to deer through various mechanisms. One method is the topical application of chemical repellents such as sulfur, selenium, and bittering agents, which can be effective in deterring deer browsing for short periods of time. Another method is fertilization, which can increase the height growth of seedlings and decrease the time span during which terminal shoots are available to deer browsing.ref.19.136 ref.41.22 ref.41.22 However, the effectiveness of fertilization against deer browsing is limited because it can also increase the nutritive status of seedlings and their palatability for large herbivores.ref.41.22 ref.41.22 ref.41.22

Plant associations can also influence the likelihood of detection and vulnerability of focal plants to herbivores. Manipulating the associated vegetation, such as increasing the abundance of neighbor plant species with physical or chemical defenses, can protect tree seedlings from deer browsing. Studies have shown that favoring associational avoidance can be promising for seedling establishment over the long term.ref.30.27 ref.19.163 ref.19.163 Conversely, an increase in the abundance of palatable neighbor plants can provide alternative sources of forage that may dilute browsing risk on seedlings.ref.30.27 ref.30.27 ref.19.163

Soil pH can also play a role in reducing deer browsing. Areas with deer have consistently lower soil pH, which is consistent with increased nitrogen additions. Low-level nitrogen additions have been found to stimulate decomposition by the soil microbial community, which can reduce the availability of nutrients for plants and make them less palatable to deer.ref.42.4 ref.19.163 ref.19.163

In summary, chemical repellents, fertilization, plant associations, and soil pH can all contribute to making plants less palatable to deer. These methods can be used as part of forest ecosystem management strategies to mitigate the impacts of deer browsing on tree regeneration and vegetation diversity.ref.19.136 ref.19.163 ref.51.153

The potential negative impacts or risks associated with the use of chemical repellents include the potential to impact other flying insects and non-target organisms, as adulticides are applied over larger areas. However, when applied at label rates and under favorable operational conditions, both larvicides and adulticides have been found to have negligible impacts on non-target organisms. Additionally, the use of certain pesticides, such as reduced-risk products, may have sublethal effects on the behavior and life history performance of natural enemies, even if there is less acute mortality.ref.62.61 ref.62.59 ref.62.61 It is important to consider the selectivity of pesticide products with respect to key natural enemies, as some pesticides can disrupt biological control of secondary pests. The National Pollutant Discharge Elimination System (NPDES) is a federal permitting program that regulates point source discharges from pesticide applications to waters in the United States, which may affect the application of chemicals for mosquito control to wetlands. The NPDES requires operators to minimize pesticide discharges, monitor for and report any adverse incidents, and implement integrated pest management practices to minimize the discharge of pesticides to waters of the U.S..ref.62.61 ref.62.62 ref.62.61 It is worth noting that there are ongoing debates and discussions regarding the impact of the NPDES on mosquito control entities, including the burden of compliance and coordination with multiple NPDES plans. Overall, the potential negative impacts and risks associated with the use of chemical repellents should be carefully considered and managed to minimize any adverse effects on non-target organisms and the environment.ref.62.62 ref.62.61 ref.62.62

The document excerpts do not provide specific information about the likelihood of certain types of plants being affected by chemical repellents.

2. Fertilization: Fertilization can potentially contribute to deer resistance in perennials. When seedlings are fertilized, their height growth increases, which in turn decreases the time span during which the terminal shoots are available for deer browsing.ref.19.136 ref.41.22 ref.41.22 However, the effectiveness of fertilization against deer browsing is limited. This limitation may be attributed to the fact that fertilization can also increase the nutritive status of seedlings and make them more palatable to large herbivores.ref.41.22 ref.41.22 ref.41.22

3. Plant associations: Manipulating plant associations can play a role in deterring deer browsing. By favoring associational avoidance, plant species with physical defenses (e.g., spines) or chemical defenses (e.g., toxic components) can be introduced to increase the abundance of neighbor plant species.ref.19.163 ref.19.163 ref.51.153 This can help protect tree seedlings from deer, as the associated vegetation can influence the likelihood of detection and vulnerability of focal plants to herbivores.ref.19.163 ref.19.163 ref.51.153

4. Morphological and physiological traits: The morphological and physiological traits of plants can also contribute to their resistance against deer browsing. Smaller trees are preferentially browsed by deer because they have more leaves and branches at heights that are easily accessible to deer.ref.19.163 ref.19.163 ref.51.153 Additionally, these smaller trees have thin and soft bark, making them more susceptible to browsing. The trunk size of these trees is also suitable for antler fraying, further contributing to their vulnerability to deer browsing.ref.19.163 ref.51.153 ref.19.178

5. Phylogenetic diversity: Deer herbivory can act as a biotic filter, impacting species diversity, species richness, and phylogenetic diversity. Deer have been found to suppress browse-intolerant species while promoting the coexistence of closely related browse-tolerant species.ref.43.19 ref.43.18 ref.43.19 This suggests that deer browsing can influence the composition and diversity of plant communities, favoring certain species over others based on their susceptibility to browsing.ref.38.0 ref.19.163 ref.43.19

It is important to note that while the provided information covers several factors contributing to deer resistance in perennials, it may not encompass all possible chemical compounds and physical characteristics. Further research and studies are necessary to gain a more comprehensive understanding of this topic.ref.19.136 ref.41.22 ref.51.153

The document excerpts do not provide information about other chemical compounds besides sulfur, selenium, and bittering agents that have been found to be effective in repelling deer from perennials.ref.31.10 ref.31.10

The provided document excerpts do not directly address the question of how the abundance of neighboring plant species influences the likelihood of detection and vulnerability of focal plants to deer herbivory. There is no specific information on the relationship between neighboring plant species abundance and the likelihood of detection or vulnerability to deer herbivory in the given excerpts.ref.51.154 ref.19.136 ref.51.153

Specific morphological and physiological traits that make certain plants more resistant to deer browsing compared to others include browse tolerance, basal meristems, and abiotic pollination mode. Plants that are categorized as grass or sedge browse types with abiotic pollination mode are considered browse tolerant because they have basal meristems and are able to regrow following browsing. On the other hand, plants categorized as broadleaf herbs and woody browse types are classified as susceptible to deer browsing.ref.43.18 ref.43.18 ref.43.17 Additionally, plants with brightly colored flowers and compound inflorescences pollinated by animals, as well as those producing large seeds and fleshy fruits dispersed by animals, are more resistant to deer browsing. It is also observed that deer tend to visually cue in on biotically pollinated plants with conspicuous flowers. Furthermore, the browse type and pollination mode of plants exhibit significant phylogenetic clustering, indicating that these traits have a strong phylogenetic signal.ref.43.17 ref.43.18 ref.43.18 Overall, deer browsing promotes the coexistence of closely related browse-tolerant species and filters out species with browse-susceptible traits.ref.43.18 ref.43.18 ref.43.17

Mechanisms of Deer Deterrence in Perennials

Deer deterrence in perennials can be achieved through various mechanisms, including the timing of deer herbivory, physical protection of seedlings, presence of coarse woody debris, and the resilience of herbaceous communities.ref.19.137 ref.19.136 ref.42.4

1. Timing of deer herbivory: The timing of deer herbivory plays a crucial role in determining the impact on plant survival and fecundity. Depending on when browsing occurs, the magnitude of deer effects can vary.ref.19.163 ref.42.4 ref.42.4 For instance, if deer browse during critical growth stages or during the reproductive phase, the impact on plant fitness can be significant. Therefore, understanding the timing of deer herbivory is important in managing and mitigating its effects on perennials.ref.42.4 ref.42.4 ref.19.163

2. Physical protection of seedlings: To prevent deer browsing, physical protection measures can be implemented, such as using plastic tubes or wire fencing to shield tree seedlings. These physical barriers can effectively deter deer and reduce the extent of browsing damage.ref.41.21 ref.41.22 ref.41.22 By providing a physical barrier, these measures allow seedlings to establish and grow without being subjected to deer browsing.ref.41.22 ref.41.22 ref.41.10

3. Presence of coarse woody debris: The presence of coarse woody debris can also contribute to deer deterrence in perennials. Coarse woody debris refers to fallen or dead trees, branches, and twigs that accumulate on the forest floor.ref.19.136 ref.19.137 ref.19.137 This debris can limit browsing of plants by impeding deer movement and access to desirable vegetation. As a result, the presence of coarse woody debris can help protect perennials from deer browsing.ref.19.137 ref.42.4 ref.19.136

4. Resilience of herbaceous communities: The resilience of herbaceous communities in the boreal forest to chronic browsing can be achieved through a combination of deer population reduction and forest clearcutting. By reducing the density of deer populations and employing clearcutting practices, the resilience of herbaceous communities can be enhanced.ref.51.154 ref.51.154 ref.51.154 This resilience allows for the recovery and persistence of plant species that are important for maintaining ecosystem functionality and biodiversity.ref.51.154 ref.51.154 ref.45.26

Ecological Factors Contributing to Deer Resistance in Plants

In addition to the aforementioned factors, ecological factors also play a role in contributing to deer resistance in plants. These factors include the presence of toxic plants, small herb species, and perennial herbs that enter dormancy at an early date.ref.19.136 ref.19.163 ref.51.153

1. Presence of toxic plants: Certain plants possess toxic compounds that make them less palatable or even harmful to deer. These toxic plants have evolved chemical defenses to discourage deer browsing.ref.19.136 ref.19.163 ref.51.153 By producing compounds that are unappealing or detrimental to deer, these plants reduce their chances of being consumed.ref.19.136 ref.19.163 ref.51.141

2. Small herb species: Small herb species that do not increase in height are less susceptible to deer feeding. Plants such as Galium paradoxum, Adoxa moschatellina, and Pseudostellaria palibiniana fall into this category.ref.51.141 ref.19.150 ref.19.150 Their small size and lack of vertical growth make them less accessible to deer, reducing the likelihood of browsing.ref.19.178 ref.19.163 ref.19.163

3. Perennial herbs with early dormancy: Perennial herbs that enter yearly dormancy at an early date also exhibit resistance to deer browsing. Examples of such plants include Adoxa moschatellina, Trillium spp., and Cardamine leucantha.ref.19.136 ref.51.141 ref.51.142 By withering until the summer and entering dormancy early, these plants reduce their palatability to deer and increase their chances of survival.ref.19.136 ref.41.22 ref.51.141

It is important to recognize that the effects of deer on plant communities can be complex and can vary over time and space. The density of deer populations and the availability of plant resources can modify the influence of deer browsing on plants. Deer browsing can lead to changes in species composition, nutrient cycling, and soil stability within plant communities.ref.42.4 ref.51.153 ref.42.4 The recovery of plant community biodiversity following a period of high deer population density can be slow, and the success of revegetation efforts may depend on the persistence of certain plant species under intense herbivory.ref.51.153 ref.42.4 ref.42.4

In conclusion, deer resistance in perennials can be influenced by a variety of factors, including chemical repellents, fertilization, plant associations, morphological and physiological traits, and phylogenetic diversity. The timing of deer herbivory, physical protection measures, presence of coarse woody debris, and the resilience of herbaceous communities are mechanisms that can contribute to deer deterrence. Ecological factors, such as the presence of toxic plants, small herb species, and perennial herbs with early dormancy, can also play a role in deer resistance.ref.19.136 ref.51.153 ref.51.153 However, it is important to acknowledge that further research is needed to fully understand and uncover additional insights into the chemical compounds and physical characteristics that contribute to deer resistance in perennials.ref.19.136 ref.51.153 ref.51.153

Horticultural Aspects of Deer-Resistant Perennials

The Impact of Deer Grazing on Vegetation in Forests and Riparian Areas

Deer grazing has significant impacts on vegetation in forests and riparian areas. In horticultural settings, deer-resistant perennials are able to withstand deer grazing and maintain their growth and appearance. However, in natural forest ecosystems, deer grazing can lead to changes in forest floor vegetation, a decrease in height and coverage of the herbaceous layer, and a decrease in species richness in various forest communities.ref.19.137 ref.51.128 ref.19.137

The use of protective fences can help in the recovery of vegetation populations affected by deer grazing. This includes tall perennial herbs and endangered species. The effectiveness of fencing depends on the susceptibility of different types of forest vegetation to deer influence.ref.19.137 ref.51.128 ref.51.127 Fencing may be necessary in certain areas to ensure the protection and recovery of vegetation.ref.51.127 ref.51.128 ref.19.137

In boreal forests, deer consume forest-floor vegetation and tree leaves. Their dietary selections are influenced by tree-species composition and food-resource availability. Smaller trees are preferentially browsed by deer due to their accessibility and suitable bark for antler fraying.ref.51.153 ref.19.163 ref.19.163 However, the temporal changes in dietary selection and browsing damage on plants associated with deer density changes have been poorly documented.ref.19.163 ref.19.164 ref.51.154

Deer herbivory can lead to significant changes in plant communities, including alterations in species composition and functional trait assemblages. Reduced deer densities can favor plants with brightly colored flowers, compound inflorescences, and large seeds and fleshy fruits dispersed by animals. The resilience of herbaceous communities in the boreal forest to chronic browsing depends on the reduction of deer population density and forest clearcutting.ref.45.11 ref.19.163 ref.51.153

The timing of deer herbivory is an important factor to consider. The effects of deer on plant populations and communities, as well as ecosystem properties and processes, are still not fully understood and require further study. The vulnerability of plant communities to being pushed into an alternate stable state by intense deer herbivory and the magnitude of temporal and spatial variation in deer effects on plants are also areas that need more research.ref.51.153 ref.19.163 ref.19.163

Deer Grazing in Horticulture and the Importance of Management Strategies

Deer grazing poses challenges in horticultural settings, but there are ways to mitigate its impact. The selection of deer-resistant perennials should take into account factors such as plant size, growth form, and unpalatability. Deer deterrence mechanisms in horticulture include physical protection of tree seedlings with plastic tubes and wire fencing, the presence of coarse woody debris, dispersion of logging slashes over regenerating areas, and the timing of deer herbivory.ref.19.137 ref.19.136 ref.51.141

These mechanisms can be optimized in horticulture by considering factors such as the cost-effectiveness of physical protection methods, the use of fallen logs and aggregates to limit browsing, and the timing and intensity of deer herbivory. Additionally, the composition and availability of food resources in forests can affect the dietary selections of deer, and understanding these relationships can aid in the design of management plans.ref.19.163 ref.51.153 ref.42.4

Integrated management strategies that consider both deer populations and forest regeneration are important. Stakeholder involvement in decision-making is also crucial to ensure effective management of deer grazing in horticultural settings. The vulnerability of different plant communities to intense deer herbivory and the effects of deer on ecosystem properties and processes are still not well understood, highlighting the need for further research and the development of comprehensive management strategies.ref.19.137 ref.51.153 ref.19.137

Methods to Enhance Deer Resistance in Plants

There are various methods to enhance the deer resistance of plants through breeding or manipulation of chemical compounds. These methods can be used to minimize the impact of deer grazing on vegetation in horticultural settings. The three main methods discussed in the document excerpts are:ref.19.136 ref.19.137 ref.51.153

1. Topical application of chemical repellents: Chemical repellents such as sulfur, selenium, and bittering agents can be applied to plants to deter deer browsing. However, the effectiveness of these repellents is limited to short periods of time.ref.31.10

2. Fertilization: Fertilization can increase the height growth of seedlings and decrease the time span during which terminal shoots are available to deer browsing. However, the effectiveness of fertilization against deer browsing is limited, as it can also increase the palatability of seedlings for large herbivores.ref.41.22 ref.41.10 ref.41.22

3. Manipulation of plant associations: Plant associations, such as the presence of herbs, grasses, and ferns, can influence the likelihood of detection and vulnerability of focal plants to herbivores. Manipulating the associated vegetation by increasing the abundance of neighbor plant species with physical or chemical defenses can protect tree seedlings from deer browsing.ref.19.163 ref.30.27 ref.19.163 This strategy, known as associational avoidance, has shown promising results in protecting seedlings from browsing over both short and long terms.ref.30.27 ref.19.163 ref.30.27

It is worth noting that breeding for traits such as increased resistance to browsing can be a potential approach to enhance deer resistance in plants. While not specifically mentioned in the document excerpts, breeding can be an important tool in developing deer-resistant plant varieties for horticultural settings.ref.45.11 ref.51.141 ref.45.11

Conclusion

Deer grazing has significant impacts on vegetation in both natural forest ecosystems and horticultural settings. In natural forests, deer grazing can lead to changes in species composition, functional trait assemblages, and forest structure. In horticultural settings, deer-resistant perennials can thrive despite the challenges posed by deer grazing.ref.19.137 ref.19.137 ref.42.4

Management strategies that consider both deer populations and forest regeneration are important in mitigating the impacts of deer grazing. The timing and intensity of deer herbivory, as well as the composition and availability of food resources, play a crucial role in designing effective management plans. Additionally, methods such as physical protection, manipulation of plant associations, and the use of chemical repellents can be used to enhance the deer resistance of plants in horticultural settings.ref.19.137 ref.19.137 ref.19.137

Further research is needed to better understand the specific impacts of deer herbivory on different plant communities and to develop more comprehensive management strategies. The involvement of stakeholders in decision-making and the consideration of breeding as a method to enhance deer resistance in plants are also important aspects to consider. By understanding and implementing these strategies, it is possible to minimize the impact of deer grazing on vegetation and ensure the successful growth and appearance of plants in both natural and horticultural settings.ref.19.137 ref.51.153 ref.19.163

Interactions Between Deer and Deer-Resistant Perennials

Impacts of Deer Browsing on Plant Communities

The timing and intensity of deer herbivory have significant impacts on the effectiveness of management strategies in mitigating the impacts of deer grazing on plant communities. Timing of deer herbivory plays a crucial role in determining the magnitude of deer effects on plant survival and fecundity. For example, studies have shown that the timing of simulated herbivory, such as winter clipping versus summer clipping, can have different effects on plant mortality.ref.19.163 ref.51.153 ref.51.153 Additionally, the timing and intensity of clipping can affect plant fecundity, with reductions in fruit number being proportional to clipping intensity when performed early in the season.ref.51.153 ref.19.163 ref.19.163

Furthermore, the intensity of deer herbivory can also impact the effectiveness of management strategies. The effects of deer on plant populations and communities may be limited to certain combinations of deer densities, plant densities, and site characteristics. The density of the plants consumed and the availability of plant resources can modify the influence of deer density on the magnitude of deer effects on vegetation.ref.51.153 ref.51.153 ref.51.153

It is important to note that the specific effects of deer herbivory on plant communities can vary depending on the region and community type. The vulnerability of plant communities to being pushed into an alternate stable state by intense deer herbivory is not well understood, and it is unclear which communities are likely to be affected.ref.51.153 ref.19.163 ref.19.163

Overall, the timing and intensity of deer herbivory are important factors to consider when implementing management strategies to mitigate the impacts of deer grazing on plant communities. However, more research is needed to fully understand the complex interactions between deer density, plant abundance, and resource availability, as well as the long-term effects of deer herbivory on plant populations and communities.ref.51.153 ref.51.153 ref.51.153

Specific physical protection methods that can be used to enhance the deer resistance of plants in horticultural settings include:ref.19.136 ref.19.136 ref.19.136

1. Topical application of chemical repellents: Chemical repellents such as sulfur, selenium, and bittering agents can be applied to plants to deter deer browsing. However, the effectiveness of these repellents is limited to short periods of time (days or months).ref.31.10 ref.31.10

2. Fertilization: Fertilization can increase the height growth of seedlings and decrease the time span during which terminal shoots are available to deer browsing. However, the effectiveness of fertilization against deer browsing is limited, possibly due to increased palatability of fertilized seedlings.ref.41.22 ref.41.10 ref.41.22

3. Manipulation of plant associations: Plant associations, such as the presence of neighbor plant species with physical or chemical defenses, can influence the likelihood of detection and vulnerability of focal plants to herbivores. Increasing the abundance of neighbor plant species with defenses such as spines or toxic components can protect tree seedlings from deer browsing.ref.19.163 ref.30.27 ref.30.26

4. Physical protection: Physical protection methods such as using plastic tubes and wire fencing can prevent deer browsing on tree seedlings. However, these methods are often limited to highly valuable tree species due to their high costs.ref.19.163 ref.19.180 ref.19.163

5. Coarse woody debris: The presence of coarse woody debris can limit browsing of plants growing within aggregates or in the presence of tall fallen logs. This can provide protection to plants from deer browsing.ref.19.163 ref.19.163 ref.51.154

It is important to note that the effectiveness of these methods may vary depending on the specific horticultural setting and the behavior of the deer population. Further research is needed to assess the long-term effectiveness of these methods and their applicability to different deer-forest systems.ref.19.137 ref.19.137 ref.19.137

To involve stakeholders in decision-making processes for developing more comprehensive management strategies for deer-resistant perennials, the document suggests the following approaches:ref.31.24 ref.31.24 ref.31.24

1. Assess: Define the problem, build conceptual models, articulate hypotheses to be tested, explore alternative management actions, and identify/involve all relevant stakeholders.

2. Design: Design experimental treatments (with control and replications) to test alternative hypotheses, develop a monitoring plan, and secure a multiyear budget.

3. Implement: Implement the design in the field and monitor the implementation.

4. Monitor: Implement the monitoring plan as designed.

5. Evaluate: Analyze the data, compare results with predictions/hypotheses, identify uncertainties and assumptions.

6. Adjust: Communicate results to stakeholders and decision-makers, document meaningful learning, and change actions or instruments based on what was learned. Restart a new loop in the cycle.

The document emphasizes the importance of involving all relevant stakeholders in the decision-making process and developing a "shared rationality" for adaptive management to succeed. It suggests that trust among stakeholders is crucial and that transparency and power balance should be integral parts of the decision-making process. The document also highlights the need for coordination and integration of actions on both deer populations and vegetation, as well as the development of adaptive management plans that are repeatedly updated with new data and results.ref.59.422 ref.59.425 ref.59.422

Deer browsing has been found to have significant impacts on the diversity and composition of plant communities. Studies have shown that deer browsing can decrease the diversity of insect communities, alter the structure and function of soil microbial food webs, and increase the risks of soil erosion and landslides in mountainous areas.ref.51.153 ref.38.0 ref.19.161

Deer consume forest-floor vegetation and tree leaves, and their browsing damage occurs intensively on certain plant species among a wide array of co-occurring species. The composition of plant communities can be affected by selective browsing by deer, with palatable, nutrient-rich species being consumed when available and lesser quality browse being consumed when high-quality sources are depleted. As a result, unpalatable, browse-tolerant, and non-preferred plant species are commonly observed in heavily browsed areas.ref.19.163 ref.51.154 ref.19.161 This selective browsing can lead to reductions in forest understory species richness and can even result in plant population extirpations.ref.51.154 ref.19.163 ref.19.161

Deer browsing can also influence the richness of herbaceous taxa through direct and indirect effects. It involves changes in dominant browsing-tolerant taxa and the presence of preferred plant species. The effects of deer browsing on plant diversity patterns can also be influenced by factors such as browse type and pollination mode.ref.38.0 ref.38.0 ref.51.153 The impacts of deer browsing on plant communities can be complex, involving chains of interactions among dominant browsing-tolerant taxa and preferred plant species.ref.38.0 ref.38.0 ref.43.18

It is important to note that the optimal deer density for any particular site will vary with management objectives and the plant community. However, keeping deer populations at more moderate densities is a prudent management option. This can help mitigate the potential irreversible effects of deer overbrowsing on plant communities.ref.45.11 ref.45.11 ref.45.11

Cascading Effects of Deer Browsing on Ecosystems

The cascading effects of deer browsing on other organisms in ecosystems include changes in plant diversity patterns, decreased diversity of insect communities, alterations in the structure and function of soil microbial food webs, and increased risks of soil erosion and landslides in mountainous areas.ref.42.4 ref.51.153 ref.38.0

Deer browsing and soil disturbance have been found to influence herbaceous plant diversity patterns in boreal forests. Deer browsing influences richness via complex chains of interactions involving dominant browsing-tolerant taxa and preferred plant species. This indicates that the effects of deer browsing on plant communities can extend beyond direct interactions with plants.ref.38.0 ref.38.0 ref.51.154

Deer browsing activity can modify the flow of energy and nutrients in forest ecosystems, impacting primary productivity and nutrient cycling. Although the impacts of deer browsing on mature canopy trees have been less studied, it is hypothesized that the exclusion of deer from a forest can lead to greater growth of mature trees due to increased productivity and nutrient cycling.ref.42.4 ref.42.4 ref.19.161

The impacts of deer browsing on ecosystems can be significant and have implications for plant communities, insect communities, soil microbial communities, and ecosystem processes. The alteration of energy and nutrient cycles, as well as changes in plant diversity patterns, can have cascading effects across the entire ecosystem.ref.42.4 ref.38.0 ref.51.153

Long-Term Implications of Deer Browsing and the Use of Deer-Resistant Perennials

The long-term implications of deer browsing and the use of deer-resistant perennials in ecosystems are important to consider.ref.19.161 ref.42.4 ref.19.164

Deer browsing has a negative influence on riparian forests. Heavy browsing and debarking by deer can result in the decline of forest-floor vegetation and dieback of mature trees. The browsing activity of deer is influenced by factors such as tree size structure and species preferences.ref.19.161 ref.51.169 ref.19.164

The resistance to deer browsing differs among tree species, with smaller mature trees having lower browsing resistance. Riparian forests are important ecosystems that provide specialized habitats and resources for wildlife, support and maintain faunal and floral diversity, and prevent soil erosion. However, the majority of riparian forests in Japan have disappeared due to increased industrial or agricultural land use and heavy browsing pressure by deer.ref.19.164 ref.19.180 ref.19.164

Deer browsing and the decline of forest-floor vegetation have a negative impact on the overall health and biodiversity of riparian forests. Riparian forests are important ecosystems that provide specialized habitats and resources for wildlife, support and maintain faunal and floral diversity, and prevent soil erosion. However, heavy browsing and debarking by deer in riparian forests have resulted in the decline of forest-floor vegetation and dieback of mature trees.ref.19.164 ref.51.154 ref.19.161 This browsing activity of deer negatively influences riparian forests and can lead to changes in forest structure and composition. The reduction in understory vegetation can also increase surface soil erosion, leading to deterioration in stream water quality and detrimental effects on aquatic life. The decline of forest-floor vegetation and the negative impacts on riparian forests are particularly concerning in areas where deer populations are overabundant.ref.19.161 ref.19.253 ref.51.169 It is important to implement preventive management strategies, such as deer exclusion fencing and selective conservation of tree-seed sources, to protect and manage riparian forests effectively.ref.51.169 ref.51.231 ref.19.137

Specific tree species that have been found to be more resistant to deer browsing include Ulmus davidiana Planch. var. japonica, Acer argutum, Ulmus laciniata, and Prunus hispida.ref.19.179 ref.19.179 ref.19.180 These species have shown different levels of resistance to deer browsing, with Ulmus davidiana Planch. var. japonica being the most resistant.ref.19.179 ref.19.179 ref.19.180 The heavy browsing and debarking by deer in riparian forests have resulted in the decline of forest-floor vegetation and dieback of mature trees. The damage to these species is mainly induced by their small tree size structure, which makes them easier targets for browsing by deer. The resistance of these species to deer browsing affects the overall composition and structure of riparian forests, leading to a decline in forest-floor vegetation and an increase in tree mortality.ref.19.161 ref.19.164 ref.51.154 To effectively manage riparian forests, it is recommended to protect and manage mature trees of these resistant species with small diameters. Immediate preventive management is necessary to prevent further browsing damage by deer in riparian forests.ref.19.161 ref.19.180 ref.51.169

The document excerpts provide information about the negative impacts of deer browsing on riparian forests and their associated ecosystems. It is mentioned that riparian forests in Japan have been subjected to heavy browsing pressure by deer, resulting in the decline of forest-floor vegetation and dieback of mature trees. The deer population is expected to continue to increase and expand throughout Japan, leading to increasingly serious damage to riparian forests.ref.19.161 ref.19.164 ref.51.154

In terms of alternative strategies to mitigate the negative impacts of deer browsing, the document suggests the use of deer-exclusion fences as an effective means of forest management. However, these fences can only protect limited areas of forest due to high installation and maintenance costs. Another alternative method is the control of the deer population through hunting or culling, but this approach may be insufficient due to the declining number of hunters in Japan.ref.51.169 ref.19.180 ref.19.180

Immediate preventive management is required to address browsing damage by deer before it expands. The document mentions the selective conservation of tree-seed sources as a temporal and immediate activity that can be implemented until a viable management program becomes operational. Additionally, protecting and managing mature trees of certain species with small diameters, such as shrub species, through the use of metallic-mesh trunk protectors is recommended in riparian forests of similar species composition and size structure.ref.19.180 ref.51.169 ref.19.161

The increase and expansion of deer populations in Japan are expected to cause increasingly serious damage to riparian forests due to browsing activity. This highlights the need for proactive responses and increased deer harvest rates to manage overabundant deer populations.ref.51.154 ref.19.164 ref.19.161

The potential trade-offs of planting deer-resistant perennials include the impact on native plant species. The presence of deer overpopulation can lead to decreases in plant populations, particularly in areas with sudden increases in deer population density. The surviving plants in such areas tend to have characteristics that contribute to their survival in the presence of deer overpopulation, such as being toxic plants, small herb species that do not increase in height, or perennial herbs that wither and enter dormancy early in the year.ref.19.136 ref.45.11 ref.45.11

Deer herbivory can have negative effects on plant communities, including a reduction in species diversity. The effects of deer on plant populations and communities can be significant and may vary depending on factors such as deer densities, plant densities, and site characteristics. Timing of deer herbivory is also important, as the effects on plant survival and fecundity can vary depending on the timing and intensity of herbivory.ref.51.153 ref.19.163 ref.51.153

Managing deer populations at more moderate densities is recommended to mitigate potential negative impacts on native plant species. It is important to note that the effects of deer herbivory on plant populations and communities can be complex and may vary depending on specific circumstances. The presence of deer overpopulation can have long-lasting effects on vegetation, and the recovery of plant community biodiversity after reducing deer density can be slow.ref.41.41 ref.41.41 ref.41.41

In conclusion, deer browsing can have significant impacts on plant communities and ecosystems. It can decrease the diversity of insect communities, alter soil microbial food webs, and increase the risks of soil erosion and landslides. The effects of deer browsing on plant communities can be complex, involving selective browsing, changes in dominant browsing-tolerant taxa, and impacts on herbaceous plant richness.ref.42.4 ref.38.0 ref.51.153 Furthermore, deer browsing can have cascading effects on ecosystems, influencing plant diversity patterns, energy and nutrient cycling, and ecosystem processes. The long-term implications of deer browsing and the use of deer-resistant perennials should be considered, including the negative influence on riparian forests and potential trade-offs with native plant species. Managing deer populations at more moderate densities is recommended to mitigate potential negative impacts on plant communities and native species.ref.19.161 ref.42.4 ref.51.154

Practical Applications and Benefits of Deer-Resistant Perennials

Strategies for Deer Deterrence in Horticulture and Landscape Design

The impacts of deer on tree regeneration in horticulture and landscape design can be mitigated through various strategies. One effective approach is the physical protection of tree seedlings using plastic tubes and wire fencing. These barriers prevent deer from accessing the seedlings and browsing on them.ref.42.4 ref.19.153 ref.29.26 However, it is important to note that the use of these physical barriers is limited to highly valuable tree species within specific locations due to their high costs.ref.19.153 ref.19.153 ref.29.26

Another strategy for deer deterrence is the presence of coarse woody debris, such as fallen logs. This debris can limit browsing by creating obstacles or providing cover for plants. Additionally, the dispersion of logging slashes over regenerating areas can be an inexpensive method to deter deer browsing in the early stages of tree seedling establishment.ref.19.180 ref.19.180 ref.19.180

Deer protection fences are also effective for mitigating the impacts of deer on tree regeneration. These fences create a physical barrier that prevents deer from accessing the area and browsing on the seedlings. However, it is important to consider the costs and logistics associated with the installation and maintenance of these fences.ref.51.128 ref.19.137 ref.19.180

Reducing local deer densities to a level of ≤7.5 deer·km–2 has been shown to allow for the natural regeneration dynamics of forests and the recovery of browse-sensitive plant species. By reducing the number of deer in an area, the pressure on the plant communities is decreased, allowing for the successful regeneration of trees and the recovery of sensitive plant species.ref.45.11 ref.45.11 ref.45.11

The timing of deer herbivory is an important consideration when implementing strategies for deer deterrence. The timing can affect the magnitude of deer effects on plant survival and fecundity. For example, if deer browse on plants during a critical growth stage, it may have a more significant impact on their long-term survival and reproductive success.ref.42.4 ref.19.163 ref.41.22 Therefore, it is crucial to understand the timing of deer herbivory and consider it when implementing deer deterrence strategies.ref.19.163 ref.42.4 ref.19.163

The vulnerability of plant communities to being pushed into an alternate stable state by intense deer herbivory is not well understood. Further research is needed to determine which communities are likely to be affected and to what extent. Understanding the potential for shifts in plant communities is essential for effective deer management and conservation efforts.ref.51.153 ref.51.153 ref.51.153

The effects of deer on ecosystem properties and processes, such as nutrient cycling and biomass distribution, have received little study and are poorly understood. It is important to explore these effects to better understand the overall impacts of deer on ecosystems and to develop effective management strategies.ref.42.4 ref.42.4 ref.42.4

Overall, maintaining moderate deer densities and implementing physical protection measures, such as plastic tubes, wire fencing, and deer protection fences, can help mitigate the impacts of deer on horticulture and landscape design. Additionally, reducing local deer densities and considering the timing of deer herbivory are important factors to consider in effective deer deterrence strategies.ref.19.137 ref.19.136 ref.19.137

Deer Deterrence Methods: Companion Planting, Physical Barriers, and Repellents

Companion planting, physical barriers, and repellents are three effective methods for deterring deer and mitigating their impacts on tree regeneration and browsing on seedlings.ref.41.22 ref.41.22 ref.19.180

Companion planting involves manipulating the associated vegetation to influence the likelihood of detection and vulnerability of focal plants to herbivores. By increasing the abundance of neighbor plant species with physical or chemical defenses, such as spines or toxic components, tree seedlings can be protected from deer browsing. This method has been shown to be effective in protecting seedlings from deer browsing over both short and long terms.ref.30.27 ref.19.163 ref.19.163 Studies have also shown that an increase in the abundance of palatable neighbor plants can provide alternative sources of forage that may dilute browsing risk on seedlings through contrasted associational defense.ref.30.27 ref.30.27 ref.19.163

Physical barriers, such as plastic tubes and wire fencing, can be used to physically protect tree seedlings from deer browsing. These barriers prevent deer from accessing the seedlings and browsing on them. However, the high costs associated with these methods limit their use to highly valuable tree species within specific locations.ref.41.22 ref.41.22 ref.19.180 Coarse woody debris, such as fallen logs, can also limit browsing of plants growing within aggregates or in the presence of tall fallen logs. Additionally, the dispersion of logging slashes over regenerating areas can be an inexpensive method to deter deer browsing. However, its effectiveness is limited to the early stage of tree seedling establishment.ref.19.163 ref.19.163 ref.19.180

Chemical repellents, such as sulfur, selenium, and bittering agents, can be topically applied to deter deer browsing. These repellents make the foliage of plants unpalatable to deer, reducing the likelihood of browsing. However, their effectiveness is currently restricted to short periods of time and may require frequent reapplication.ref.31.10

Fertilization is another chemical method that can decrease the time span during which terminal shoots are available to deer browsing by increasing the height growth of seedlings. This technique reduces the palatability of seedlings for large herbivores by increasing their nutritive status. However, its effectiveness is limited due to the potential increase in the nutritive status and palatability of seedlings.ref.41.22 ref.41.10 ref.41.22

Overall, companion planting, physical barriers, and repellents all play a role in deterring deer by either making seedlings less attractive to deer or physically preventing deer from accessing them. These methods can be integrated into forest ecosystem management strategies to mitigate the impacts of deer on tree regeneration.ref.19.153 ref.42.4 ref.19.153

Economic and Environmental Benefits of Using Deer-Resistant Perennials

Using deer-resistant perennials in horticulture and landscape design can provide both economic and environmental benefits.ref.19.136 ref.19.136 ref.45.12

The document excerpts provide information on various companion planting techniques that have been effective in deterring deer from eating seedlings.ref.41.22 ref.19.136 ref.45.11

1. Manipulation of associated vegetation: The manipulation of the associated vegetation, such as herbs, grasses, and ferns, has been proposed as a mitigation measure against browsing on tree seedlings. By increasing the abundance of neighbor plant species with physical (e.g., spines) or chemical (e.g., toxic components) defenses, tree seedlings can be protected from deer browsing.ref.19.163 ref.19.163 ref.19.163

2. Favoring associational avoidance: Increasing the abundance of neighbor plant species with physical or chemical defenses can protect tree seedlings from deer. Studies have shown that this technique can be effective in the short term (≤5 years) and even over the long term.ref.19.136 ref.45.11 ref.41.22

3. Unpalatable plants: Planting unpalatable species or species with toxic components can deter deer from browsing on seedlings. These plants are less likely to be consumed by deer due to their unpalatability.ref.19.163 ref.19.136 ref.51.141

4. Physical protection: Using physical barriers such as plastic tubes and wire fencing can prevent deer browsing on tree seedlings. However, this method is often limited to highly valuable tree species due to its high cost.ref.19.180 ref.41.22 ref.41.22

5. Coarse woody debris: The presence of coarse woody debris can limit browsing of plants growing within aggregates or in the presence of tall fallen logs. This can provide protection for seedlings against deer browsing.ref.19.163 ref.19.163 ref.19.137

6. Silvicultural actions: Silvicultural actions, such as partial cuttings and artificial regeneration through planting, can influence forage resources and environmental conditions for deer. Partial cuttings can result in the establishment of numerous tree seedlings, saturating the needs of deer and allowing palatable seedlings to grow beyond deer reach.ref.29.26 ref.42.4 ref.19.137 Fencing at the stand level can also be used to protect forest plants from deer.ref.19.137 ref.19.137 ref.29.26

It is important to note that the effectiveness of these techniques may vary depending on the specific context and deer population density. Further research and experimentation are needed to assess the long-term effectiveness of these companion planting techniques.ref.19.136 ref.45.11 ref.45.11

The effectiveness of physical barriers in preventing deer from accessing plants varies depending on the specific circumstances. While there are no specific types of barriers mentioned in the provided document excerpts, it is mentioned that the use of exclosures or enclosures can be essential for studying deer herbivory in the field. These barriers can protect vulnerable plant species from continuous browsing by deer.ref.19.137 ref.19.137 ref.19.137 However, it is important to note that the constraints of time and funds may limit the use of these barriers. Additionally, the success of regeneration in the presence of barriers can depend on factors such as the abundance of neighbor plant species with physical or chemical defenses. Further research is needed to fully understand the effectiveness of different types of barriers in preventing deer access to plants.ref.19.137 ref.19.137 ref.19.137

Common types of repellents used to deter deer include chemical repellents (such as sulfur, selenium, and bittering agents), physical deterrents (such as reflector and sound devices), and biological deterrents (such as dogs and hunting for fear). These repellents are used to prevent deer from browsing on plants and tree seedlings.

However, there can be potential drawbacks and negative environmental impacts associated with using repellents. For example, chemical repellents may only be effective for short periods of time and may have limited long-term cost-effectiveness. Fertilization, another chemical method, may increase the height growth of seedlings but can also increase their palatability for deer.ref.41.22 ref.41.22 ref.41.22 Physical methods like plastic tubes and wire fencing can be expensive and limited to valuable tree species. Additionally, manipulating associated vegetation or favoring associational avoidance may protect tree seedlings from deer browsing, but the effectiveness of these methods may vary over time and depend on factors such as plant species and deer density.ref.41.22 ref.41.22 ref.41.22

It is important to consider the specific context and goals of deer management, as well as potential trade-offs between deer population control and forest regeneration. Further research is needed to better understand the long-term population-level and ecosystem-level impacts of deer browsing and the effectiveness of different deterrent methods.ref.31.20 ref.31.20 ref.31.20

One of the economic benefits is the preservation of plant populations and communities. Deer herbivory can have significant negative effects on plant populations and communities. Using deer-resistant perennials reduces the risk of damage and loss caused by deer browsing, thus preserving plant populations and maintaining their economic value.ref.19.136 ref.42.4 ref.51.154

Another economic benefit is the prevention of irreversible changes in plant communities. Deer browsing can push plant communities into alternative stable states, where the composition and structure of the community are significantly altered. By using deer-resistant perennials, the risk of these irreversible changes can be reduced, preserving the integrity and functionality of plant communities.ref.42.4 ref.19.164 ref.51.153

Using deer-resistant perennials also has environmental benefits. Deer can have impacts on ecosystem properties and processes, such as nutrient cycling, biomass distribution, and productivity. However, these effects have received little study and are poorly understood.ref.42.4 ref.19.136 ref.42.4 By reducing the intensity of deer herbivory through the use of deer-resistant perennials, the balance of these ecosystem properties and processes can be maintained.ref.19.136 ref.42.4 ref.51.153

Overall, using deer-resistant perennials in horticulture and landscape design provides economic benefits by preserving plant populations and communities, preventing irreversible changes in plant communities, and maintaining the economic value of plant species. It also has environmental benefits by maintaining the balance of ecosystem properties and processes.ref.45.11 ref.19.136 ref.45.11

Conservation Implications of Using Deer-Resistant Perennials for Native Plant Species

Using deer-resistant perennials in horticulture and landscape design can have conservation implications for native plant species.ref.19.136 ref.19.137 ref.51.144

Reducing deer densities can allow for the natural regeneration dynamics of forests and promote the recovery and regeneration of plant communities that have been impacted by deer herbivory. Studies have shown that reducing deer densities can lead to increased abundance, richness, and diversity of songbirds. This is because reduced deer densities can favor plants with brightly colored flowers and compound inflorescences that are pollinated by animals and produce large seeds and fleshy fruits dispersed by animals.ref.45.11 ref.47.25 ref.45.11 These plants provide additional food resources for songbirds and other wildlife. Therefore, using deer-resistant perennials and implementing deer control measures can contribute to the recovery and regeneration of plant communities and promote the habitat attributes required by songbird species.ref.45.11 ref.47.25 ref.45.11

Sylvicultural treatments, such as selective cutting or thinning of trees, may also aid in the recovery process by creating more suitable conditions for the growth and survival of desired plant species. However, further research is needed to fully understand the magnitude of the relationship between plant community resilience and deer control, as well as the ability of species to flower and produce fruits along different deer densities. It is also important to consider other traits and factors, such as specific leaf area, nitrogen content, and root traits, to assess the resilience of individual ecosystem functionality.ref.45.11 ref.45.11 ref.45.11

Reference ecosystems can provide valuable insights into the recovery of functionality in impacted areas. By studying reference ecosystems that have similar characteristics to the impacted areas but are not subject to intense deer herbivory, researchers can gain a better understanding of the potential recovery of functionality in these areas. This information can then inform conservation efforts and the implementation of deer control measures.ref.45.38 ref.51.154 ref.19.164

In conclusion, using deer-resistant perennials in horticulture and landscape design can have conservation implications for native plant species. It can promote the recovery and regeneration of plant communities impacted by deer herbivory, increase the abundance and diversity of songbirds, and maintain the balance of ecosystem functionality. However, further research is needed to fully understand the relationships between deer control, plant community resilience, and the recovery of ecosystem functionality.ref.45.11 ref.19.136 ref.45.11

Limitations and Challenges of Deer-Resistant Perennials

Factors Affecting the Effectiveness of Deer Deterrence in Perennials

The effectiveness of deer deterrence in perennials is influenced by various factors, including the characteristics of the plants themselves and the timing of deer herbivory. According to the provided document excerpts, plants that have survived in the presence of deer overpopulation tend to possess certain characteristics. These characteristics include being toxic plants, small herb species that do not increase in plant height, or perennial herbs that wither until the summer and enter yearly dormancy at an early date.ref.19.136 ref.41.22 ref.51.141 These plants have evolved mechanisms to deter deer browsing, such as producing compounds that are toxic or unpalatable to deer, or adopting growth strategies that make them less attractive to herbivores.ref.19.136 ref.51.141 ref.51.141

The timing of deer herbivory is also an important factor in determining the magnitude of deer effects on plant survival and fecundity. Studies have shown that the timing of herbivory can affect the mortality and reproductive structures of plants. For example, if herbivory occurs during the critical period of flower or seed production, it can significantly reduce the reproductive output of plants.ref.42.4 ref.19.163 ref.42.4 On the other hand, if herbivory occurs during the vegetative growth phase, plants may have a better chance of recovering and regrowing.ref.42.4 ref.19.163 ref.19.163

Other factors that may affect the effectiveness of deer deterrence in perennials include the vulnerability of plant communities to being pushed into an alternate stable state by intense deer herbivory, the effects of deer on ecosystem properties and processes, and the magnitude of temporal and spatial variation in deer effects on plants. The vulnerability of plant communities to being pushed into an alternate stable state refers to the potential for deer herbivory to cause a shift in the dominant plant species and alter the overall composition and structure of the plant community. The effects of deer on ecosystem properties and processes, such as nutrient cycling and biomass distribution, are also poorly understood and need further investigation.ref.42.4 ref.42.4 ref.51.153 Additionally, the magnitude of temporal and spatial variation in deer effects on plants is not well studied, and it is unclear how deer density and plant availability influence these effects. Therefore, while the provided document excerpts shed light on some of the factors that affect the effectiveness of deer deterrence in perennials, they do not provide a comprehensive analysis of all the factors at play.ref.51.153 ref.42.4 ref.51.153

Long-term Sustainability and Ecological Implications of Relying on Deer-Resistant Perennials

Relying on deer-resistant perennials for long-term sustainability presents several limitations and challenges. Firstly, there is a lack of complete life-table studies that predict the effects of deer on plant populations and communities. These studies are essential for understanding the long-term sustainability of relying on deer-resistant perennials, as they provide insights into the population dynamics of plants and the potential for population decline or extinction due to deer herbivory.ref.19.136 ref.41.22 ref.41.22

The vulnerability of plant communities to being pushed into an alternate stable state by intense deer herbivory is another unknown factor. If plant communities are unable to recover from intense deer herbivory and shift to a new stable state, it could have long-lasting effects on ecosystem structure and function.ref.51.153 ref.19.163 ref.19.163

Furthermore, the effects of deer on ecosystem properties and processes, such as nutrient cycling and biomass distribution, are poorly understood. Deer herbivory can alter the nutrient cycling dynamics in ecosystems by changing the composition and abundance of plant species. Understanding these effects is crucial for assessing the long-term sustainability of relying on deer-resistant perennials.ref.42.4 ref.42.4 ref.42.4

The magnitude of temporal and spatial variation in deer effects on plants is another important factor that needs further investigation. Deer populations can have varying effects on the survival and fecundity of plants, particularly tree seedlings and saplings. However, these effects are not widespread or usual, and factors such as deer density, plant density, and resource availability contribute to this variation.ref.41.22 ref.41.22 ref.41.22 Understanding the relative importance of these factors and their interactions in determining the occurrence of substantial deer effects on plants is crucial for managing deer populations and vegetation effectively.ref.41.22 ref.41.22 ref.41.22

Finally, the long-term effects of prolonged deer densities on forest understorey plant communities require more research. Forest understorey plants play a vital role in maintaining biodiversity and ecosystem functioning. Understanding the impacts of deer on understorey plant communities is essential for developing effective management strategies that promote long-term sustainability.ref.42.4 ref.42.4 ref.42.4

Management Approaches for Dealing with Deer Populations and Vegetation

Managing overabundant deer populations and their impacts on vegetation requires proactive responses. One approach is to reduce deer populations to low density. However, this is technically difficult and may not be socially and economically acceptable.ref.31.20 ref.31.20 ref.31.20 Maintaining trust among stakeholders is crucial for decision-making, and transparency and power balance should be integral parts of the management process.ref.31.1 ref.31.20 ref.31.20

Integration and prioritization of actions are necessary in managing deer populations and vegetation, considering trade-offs between habitat changes and other management objectives. For example, physical protection of tree seedlings, dispersion of logging slashes, and the presence of coarse woody debris are some techniques used to mitigate the impacts of deer on tree regeneration. These practices can help create favorable conditions for tree regeneration while minimizing the browsing damage caused by deer.ref.31.20 ref.31.20 ref.31.21

Impacts of Deer on Plant Communities

The impacts of deer on plant communities can lead to changes in vegetation composition, reduced biodiversity, and slower recovery of plant community biodiversity. The feeding behavior of deer can disrupt the root system, reduce vegetation cover and diversity, and contribute to the success of invasive plant species.ref.42.4 ref.51.153 ref.19.163

Deer browsing occurs intensively on certain plant species among a wide array of co-occurring species. Factors such as tree-species composition and food-resource availability in forests affect the dietary selections of deer. Smaller trees are preferentially browsed by deer because they have more leaves and branches at heights easily accessible to deer, as well as thin and soft bark.ref.19.163 ref.51.153 ref.19.163 The trunk size of these trees is also suitable for antler fraying.ref.51.153 ref.19.163 ref.19.161

The impacts of deer browsing extend beyond plant communities and can have cascading effects on other ecological components. For example, decreased diversity of insect communities may result from changes in vegetation structure and composition caused by deer browsing. Furthermore, the alteration of the structure and function of soil microbial food webs can have indirect effects on nutrient cycling and ecosystem processes.ref.42.4 ref.51.153 ref.38.0 In mountainous areas, the increased risks of soil erosion and landslides can be a consequence of deer browsing, particularly in areas where vegetation cover is reduced.ref.51.153 ref.19.163 ref.42.4

However, it is important to note that the temporal changes in dietary selection and browsing damage on plants associated with deer density changes have been poorly documented. Further research is needed to understand how changes in deer density over time affect their dietary preferences and the subsequent impacts on plant communities.ref.19.164 ref.19.163 ref.51.154

Alternative Food Sources for Deer

Deer have alternative food sources when their primary food sources are scarce. These alternative food sources include forest-floor vegetation, tree leaves, tree bark, and dead fallen leaves. Deer consume these food sources from spring to autumn and utilize tree bark and dead fallen leaves when facing food shortages, which usually occur in winter.ref.51.153 ref.19.163 ref.19.163

The availability and quality of alternative food sources can influence the browsing behavior of deer. Factors such as tree-species composition and food-resource availability in forests can affect the dietary selections of deer. Therefore, understanding the availability and nutritional value of these alternative food sources is crucial for managing deer populations and their impacts on vegetation.ref.51.153 ref.19.163 ref.42.4

In conclusion, the effectiveness of deer deterrence in perennials is influenced by various factors, including the characteristics of the plants themselves and the timing of deer herbivory. The long-term sustainability and ecological implications of relying on deer-resistant perennials present limitations and challenges that require further research. Managing deer populations and their impacts on vegetation requires proactive management approaches, considering trade-offs between habitat changes and other management objectives.ref.19.136 ref.51.153 ref.51.153 The impacts of deer on plant communities can lead to changes in vegetation composition, reduced biodiversity, and slower recovery of plant community biodiversity. Understanding the dietary selections of deer and the availability of alternative food sources is essential for managing deer populations effectively.ref.51.153 ref.51.153 ref.19.136

Works Cited