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Cyclic and extreme ecological disturbances have the capacity to alter resources and thereby animal populations. Interactions between disturbance and resource availability can influence predator-prey interactions. Predator-prey responses to ecological disturbance may be more pronounced in herbivores and their predators as herbivores track food resources that are often augmented by ecological disturbance. My objective with this dissertation was to examine how various forms of ecological disturbance influence predator-prey interactions through the lens of a case study – white-tailed deer (Odocoileus virginianus) and Florida panther (Puma concolor coryi) in southwestern Florida public and conservation lands. I quantified species-specific behavior of deer to an extreme disturbance event (i.e., Hurricane Irma), examined behavior of females with different fate outcomes to varied ecological disturbances and predation, investigated how ecological disturbance mediates the influence of human disturbance on predator-prey interactions, and quantified deer spatial ecology in response to fire, hydrology, panther and human activity. I found that deer behaviorally mediated the negative fitness impacts of Hurricane Irma. Further, I found that female deer with different fate outcomes selected areas of different ecological disturbance and the ecological disturbance type conferred different fitness costs (through differences in predation risk). Finally, I found that South Florida deer utilize diurnal times when humans are the most active to temporally reduce predation risk as panthers were more nocturnal in response to humans. My work here suggests that ecological disturbance regimes have the capacity to influence predator-prey interactions through nuanced mechanisms. Outcomes of these nuanced species-specific and predator-prey responses should be examined further. More practically, if disturbance influences aspects of animal fitness, a deeper understanding of species-specific and predator-prey responses to disturbance will improve management and conservation efforts as some regimes can be manipulated (e.g., prescribed fire). More broadly, consideration of ecological disturbance when examining predator-prey interactions may yield novel insight that deviates from predictions based on inference suggested in systems without disturbance. Highlighting nuanced predator-prey interactions mediated by ecological disturbances will improve predictions regarding species and community responses to global changes such as climate change and ecological restoration. / Doctor of Philosophy / Events that cause temporary changes to ecosystem structure and function (ecological disturbances) have the capacity to influence resources (i.e., food and shelter) for wild animals. Changes in resources as a function of ecological disturbance has the capacity to influence prey and predator species interactions. Predator-prey responses to ecological disturbance may be more pronounced in plant-eating animals (herbivores) and their predators as herbivores utilize food resources that are often altered by ecological disturbance. My objective with this dissertation was to examine how various forms of ecological disturbance influence interactions between predators and prey by using the white-tailed deer (Odocoileus virginianus) and Florida panther (Puma concolor coryi) in southwestern Florida wildlands as a case study. I quantified species-specific behavior of deer to an extreme climate event (i.e., Hurricane Irma). Next, I quantified and compared behavioral differences in responses to ecological disturbance (flooding and fire) and panther predation risk between female deer that survived and those killed by panthers during the offspring rearing season. I also investigated how ecological disturbance and human use of wildlands influenced predator-prey interactions. Finally, I characterized deer behavior in response to fire, hydrology, and panther and human activity. I found that deer changed their behavior during Hurricane Irma, presumably to offset the negative impacts of the storm as all our monitored deer survived the event. Further, I found that different ecological conditions generated by fire and flooding, respectively, influenced female behavior during the offspring rearing season in response to predation risk, and those behavioral differences may explain differences in mortality outcomes. Finally, I found that South Florida deer utilize daylight hours when humans are the most active to minimize encounters with predators as panthers were shown to be more active at night in areas with greater human use. My findings suggest that ecological disturbances have the capacity to influence predator-prey interactions in novel ways not suggested elsewhere. Outcomes of novel predator and prey interactions in response to ecological disturbance should be investigated further. More practically, if disturbance influences aspects of animal livelihood, a deeper understanding of species-specific and predator-prey responses to disturbance will improve management and conservation efforts as some disturbances can be manipulated (e.g., prescribed fire). More broadly, consideration of ecological disturbance when examining predator-prey interactions may yield novel insight that deviates from predictions based on inference suggested in systems without disturbance. Highlighting novel predator-prey interactions that is changed as a result of ecological disturbances will improve predictions regarding species and community responses to global changes through climate change and ecological restoration.

Group selection has recently emerged as an alternative silvicultural system to clearcutting in Appalachian hardwood forests, but there is little, if any, information on the effects of group selection on wildlife. Thus, I studied and compared the effects of group selection and clearcut openings on wildlife in the Jefferson National Forest, Virginia. Breeding birds were censused 1 year before and 2 years after harvesting at 20 group selection openings, 4 clearcut openings, 18 sites in the mature even-aged forest adjacent to the openings, and 29 control sites. I also compared use of group selection openings and clearcut openings by white-tailed deer. The number of species and the total number of birds decreased at the openings and in the forest adjacent to the openings after harvesting with both methods. (Seven species increased and 9 species decreased in the openings after harvesting. Four species decreased in the forest adjacent to the openings after harvesting. Indigo buntings and rufous-sided towhees increased more at the interior of clearcut openings than at the edge of clearcut openings or in group selection openings. Sites within the clearcut openings where groups of trees were left uncut were not used more by birds than clearcut sites without trees. (The number and proportion of stumps with sprouts browsed by white-tailed deer was greater in group selection openings than in clearcut openings. Clearcut and large group selection openings provided breeding habitat for the same bird species. The smaller group selection openings were not used by some species found in the clearcut openings. However, creating a variety of opening sizes probably will provide the maximum benefit for all wildlife species that use early successional habitat. The same species were negatively affected, and to a similar degree, by group selection and clearcut openings. Both types of openings had negative impacts on forest-interior bird species in the adjacent forest. However, if the same acreage is harvested, group selection will affect a greater area of adjacent forest than clearcutting, because smaller openings have greater edge to area ratios. / Ph. D.

White-tailed deer (Odocoileus virginianus) are a highly charismatic game species with considerable ecological and economic impacts across most of their range. In the Central Appalachian Mountains, deer are a keystone species in forested ecosystems. Regionally, populations vary in herd growth or decline. These fluctuations are important in that they often drive many aspects of population management and regulation, which are dependent on herd demographics. Some key population vital rates allowing better understanding of these changes in white-tailed deer herds are survival, cause-specific mortality, home-range variation, both broad and fine-scale resource selection, and ultimately population growth trends in response to changes in both population vital rates and hunter harvest regulations. In this study, I address each of these concepts within a deer population in Bath County, Virginia, that has presumably been in overall decline since the early 1990's. From June-September, 2019-2020, I monitored survival and cause specific mortality of 57 neonate white-tailed deer until 12 weeks of age. Fawn and adult female survival was 0.310 (95% CI = 0.210-0.475) and 0.871 (95%CI=0.790-0.961) respectively. During the study, I observed a total of 37 fawn mortalities and identified the cause of death using field evidence and through analyzing genetics from residual predator salvia recovered on deer carcasses. Mortalities included 28 predation events and 9 deaths from other causes (e.g., abandonment, malnutrition, or disease). Black bears accounted for 48.6% of all mortality and 64.2% of known predations within our study. My top model identified elevation as a significant predictor of fawn survival, with mortality risk increasing 20% for every 100m increase in elevation. My model using observed vital rates predicted an increasing population of λ = 1.10 (interquartile range, IQR 1.06-1.14). The population was predicted to increase by 2% with a 10% increase in doe harvest (λ = 1.02, IQR = 0.97-1.06) but declined by 7% at 20% harvest (λ = 0.93, IQR = 0.89-0.96). I found that fawning home ranges of females that successfully reared fawns to the end of the season had significantly larger home ranges than those that were unsuccessful at higher elevations. Fawning home ranges for females with fawns increased approximately 71ha in size for every 100m increase in mean home range elevation, whereas seasonal home ranges of females without fawns decreased approximately 1.5 ha for every 100m increase in mean home range elevation. Deer selected fawn-rearing areas nearer to forested edges, open habitats, and at higher elevations, while they avoided areas near disturbed and mature forests. Within the fawn rearing area, females selected locations closer to disturbed forest, open habitats, and forested edge, while avoiding mature forest habitats, and higher elevations. Females selected birth sites with higher levels of visual obstruction. Using a step-selection method for real-time resource selection across biological seasons, we found that female deer selected for open areas during the fawning, breeding, early gestational, and late gestational seasons. During the fall breeding season, females avoided forested edge, but selected for areas at higher elevations. During early gestational seasons females selected disturbed habitats and areas at higher elevations while again avoiding forested edge. Overall, my work highlights variations in population dynamics of white-tailed deer in areas of the Central Appalachian Mountains that are primarily characterized by poor habitat quality and provides novel insights into fine-scale spatial ecology of female deer across biological seasons within the region. Ultimately, while the deer population in our study was not predicted to be in decline, this work supports predation risk as being a significant factor associated with habitat quality. / Doctor of Philosophy / White-tailed deer (Odocoileus virginianus) are a game species with extensive ecological and economic impacts across most of their range. In the central Appalachian Mountains, many populations across the region vary in terms of herd size growth, stability, or decline. These fluctuations are important in that they often drive many aspects of population management and regulation, which are dependent on the status of herd demographics. Some key population vital rates that aid us in better understanding these changes in white-tailed deer herds are survival and cause-specific mortality, home-range variation in association with habitat quality and the ability to successfully reproduce, population trends under hypothetical management scenarios, and resource selection of various habitats that are available across the landscape. In this study, I address each of these concepts within a deer population in Bath County, Virginia, which has presumably been in decline since the early 1990's. As expected, fawn survival was lower than previously reported from other study areas of the Central Appalachians Mountains. Predation was the leading cause of fawn mortality, with black bears being responsible for most predation events. Fawn mortality risk was significantly associated with elevation - where fawns at higher elevations were those at greater risk. Surprisingly, the deer population in Bath County was projected to be increasing under current conditions and was also projected to be stable-to-increasing even under some hypothetical scenarios which would negatively impact population growth (i.e., 10% increase in female harvest or 17% reduction in fawn survival). Fawning home ranges of collared females which successfully reared known fawns to the end of the biological season were significantly influenced by elevation; such that females with fawns had home ranges that increased in size with increasing elevation, whereas females without fawns had home ranges which decreased slightly in size with increasing elevation. At birth sites, females selected locations characterized by higher levels of visual obstruction compared to randomly sampled areas. Of the habitat types analyzed, both selection or avoidance of specific habitats varied across both biological season and spatial scale. Ultimately, while I found that some deer populations associated with poor quality habitats in the Central Appalachians may not be in decline, deer were likely influenced greatly by habitat quality – especially pertaining to predation risk – throughout Bath County.

Deer (<i> Odocoileus </i> spp.) are an important cultural and economic resource. They are the most popular game species in the United States and the number one driver of conservation funding. On the other hand, they also cause damage to resources including to the agricultural industry, private property and to humans via deer vehicle collisions. Many areas in eastern North America have experienced a decline in white-tailed deer (<i> Odocoileus virginianus </i>) populations over the past twenty years concurrent with changes in landscape, deer harvest strategies, and increasing and expanding black bear (<i> Ursus americanus </i>) and coyote (<i> Canis latrans </i>) populations. Most studies have addressed this problem at small spatial and temporal scales and in areas where predation was assumed to be limiting population growth. We evaluated white-tailed deer fawn recruitment both directly and indirectly at relatively broader spatial and temporal scales. We studied fawn survival on Marine Corps Base Quantico in Virginia, USA from 2008–2019. We used the Kaplan-Meier estimator, and Cox-proportional hazards models to assess annual survival and factors that influence hazard risk such as sex, weather, landscape composition and configuration and food availability. On Marine Corps Base Quantico, we found an increase in red oak mast abundance increases survival and probability of fawn survival was higher during the first interval of the study (2008–2010; 0.71 [0.52–0.96]; survival probability [CI95%]) than the last three intervals (2011–2013; 0.46 [0.30–0.70]; 2014–2016; 0.48 [0.35–0.66] and 2017–2019; 0.50 [0.39–0.63]). We also found that predation was the leading source of mortality. We assessed recruitment using lactation status from hunter harvest data collected by the Virginia Department of Game and Inland Fisheries during a 22-year period in 30 counties in the Appalachian Mountains of western Virginia. We predicted lactation status as a function of landscape composition and configuration, oak mast abundance, weather, age, and predator detection rates using generalized linear mixed models. We found land cover diversity index positively and black bear detection rate negatively influenced recruitment. Age also predicted lactation status with middle-aged females (3.5–4.5 years old) having a higher lactation probability than mature (≥5.5 years old) age and young (2.5 years old) age class deer. Based on these findings, recruitment is likely to be greater in areas that are heterogeneous. Therefore, if an increase in recruitment is desired silvicultural practices such as fire and timber harvest could be used to permanently change land cover types. These silvicultural practices could also be used to increase the number of oaks on the landscape, and augment production of mature oaks as red oak mast abundance influenced fawn survival. Also reducing predation by manipulating predator densities could improve recruitment. Another potential option which needs further research, would be to reduce predator efficiency by increasing hiding cover for fawns. / Master of Science / Deer (<i> Odocoileus </i> spp.) are an important cultural and economic resource. They are the most popular game species in the United States and the number one driver of conservation funding. Conversely, they also cause damage to resources including to the agricultural industry, private property and to humans via deer vehicle collisions. Some areas in eastern North America have experienced a decline in white-tailed deer (<i> Odocoileus virginianus </i>) populations over the past twenty years concurrent with the colonization of coyotes (<i> Canis latrans </i>) as well as changes in habitat. Therefore, we aimed to determine white-tailed deer fawn survival rates and factors affecting recruitment across a large spatial and temporal scale. Recruitment is when an individual becomes part of the reproductive population. However, for harvestable populations, recruitment is when individuals can be legally harvested for the first time. On Marine Corps Base Quantico from 2008–2019, in Virginia, USA we found that probability of fawn survival was higher during the first interval of the study (2008–2010; 0.71 [0.52–0.96]; survival probability [CI95%]) than the last three intervals (2011–2013; 0.46 [0.30–0.70]; 2014–2016; 0.48 [0.35–0.66] and 2017–2019; 0.50 [0.39–0.63]). We also discovered predation was the leading cause of death and probability of survival increased with increasing red oak mast abundance. Over a large spatial (30 counties) and temporal (22 years) scale we examined fawn recruitment by predicting lactation status of female harvested white-tailed deer in the Appalachians Mountains of western Virginia. We found land cover diversity index positively and black bear (<i> Ursus americanus </i>) detection rate negatively influenced recruitment. Age also predicted lactation status with middle-aged females (3.5–4.5 years old) having a higher lactation probability than mature (≥5.5 years old) age and young (2.5 years old) age class deer. Based on these findings, recruitment is likely to be greater in areas that have a mixture of land cover types. Therefore, if an increase in recruitment is desired silvicultural practices such as fire and timber harvest could be used to permanently change land cover types. These silvicultural practices could also be used to increase the number of oaks on the landscape, and augment production of mature oaks as red oak mast abundance influenced fawn survival. Also reducing predation by manipulating predator densities could improve recruitment. Overall, we found diversity of land cover types, food availability, predators, and age influences population dynamics of white-tailed deer.

I evaluated effects of 5 intensive pine plantation establishment regimes during years 1 – 5 post-establishment on vegetation communities, loblolly pine (Pinus taeda) growth, nutritional carrying capacity for white-tailed deer (Odocoileus virginianus), habitat values for northern bobwhite (Colinus virginianus), and projected financial viability in the Lower Coastal Plain of Mississippi. Treatments were combinations of mechanical site preparation (MSP), chemical site preparation (CSP), and herbaceous weed control (HWC) designed to reflect the range of operational intensities on industrial forest lands in the southeastern U.S. Results should inform plantation management decisions throughout the region. Pine growth increased with greater treatment intensity. At age 5, trees in the most intensively managed treatment were 1.5 m taller than those in the least intensive treatment. Mechanical site preparation improved growth by alleviating soil physical problems. Growth and yield projections indicated that increased fiber yield may not justify investment in more intensive regimes; financial analysis favored the least expensive treatment, though all regimes produced potential internal rates of return > 9% when managed to financial maturity. Use of MSP with banded HWC yielded abundant low-quality deer forage sufficient for body maintenance; nutritional needs for lactating does were better served by CSP with banded HWC. Broadcast HWC reduced biomass of high-quality forbs. In this region of limited soil nutrients and abundant low-quality forages, the optimal combination of maintenance-level and lactation-level nutrition was provided by CSP or CSP and MSP combined with banded HWC. I evaluated vegetation communities for nesting, loafing, brood-rearing, and fall and winter food suitability for northern bobwhite. No treatment provided brood-rearing habitat due to combined lack of bare ground and forb coverage. Fall and winter feeding, nesting, and loafing cover were best produced by MSP and CSP combined with banded HWC. However, lack of brood-rearing cover may reduce or eliminate usable space in all treatments. Differences between vegetation communities were caused by use of CSP, which eliminated many residual woody and vine species, and by differences in broadcast versus banded HWC. Herbicide use decreased plant diversity and species richness, and impacted successional trajectory. Community differences persisted through year 5.

Ce mémoire visait à déterminer si un petit parc périurbain, en l’occurrence le Parc national du Mont-Saint-Bruno, est parvenu à maintenir l’intégrité de sa flore au cours des trente dernières années en dépit de pressions humaines croissantes et de perturbations naturelles passées, en plus d’identifier les principaux changements floristiques survenus au cours de cette période et les facteurs responsables. Pour répondre à ces objectifs, une étude historique a été réalisée, en comparant un inventaire floristique ancien (1977) à un inventaire récent (2013). Mes résultats montrent d’abord une forte croissance de la diversité alpha indigène au cours des 35 dernières années, accompagnée d’un déclin significatif de la diversité bêta (30%). Malgré cette homogénéisation taxonomique, la diversité fonctionnelle de la flore forestière s’est accrue, la rendant probablement plus résiliente aux événements perturbateurs. D’autre part, mes analyses ont révélé la progression de traits fonctionnels souvent associés à des habitats forestiers intensément broutés, révélant une certaine influence du cerf de Virginie sur la composition et la structure de la flore forestière. Enfin, mes résultats ont montré que les herbiers botaniques se révèlent être une alternative fiable aux méthodes traditionnelles pour documenter et évaluer l’impact des grands herbivores sur la morphologie des plantes broutées. Au final, cette étude a montré que les petites aires protégées périurbaines peuvent jouer un rôle majeur dans la préservation de la diversité floristique d’habitats forestiers d’intérêt, particulièrement lorsque leur statut de protection permet d’encadrer de manière stricte les activités humaines. / This study aimed to determine whether a small suburban park, namely the Mont-Saint-Bruno National Park, managed to maintain the integrity of its flora over the last thirty years despite increasing human pressures and past natural disturbances, in addition to identify the main floristic changes during this period and the drivers of observed changes. To do so, a historical study was conducted by comparing past (1977) and recent (2013) floristic surveys. First, a striking increase in alpha diversity, driven mostly by native species and associated with a significant decline (30%) in the beta diversity over the last 35 years was found. Despite this taxonomic homogenization, the functional diversity of forest flora has increased, probably increasing its resistance to disruptive events. Furthermore, analyses revealed the progression of functional traits associated with overbrowsed forest habitats, revealing some influence of white-tailed deer on the composition and structure of the forest flora. Finally, my study also showed that herbarium specimens can be used as a reliable alternative to traditional methods to document and assess the impact of large herbivores on browsed plants morphology. In conclusion, this study showed that small suburban protected areas can play a major role in the preservation of the floristic diversity of rich forest habitats, particularly when their status strictly frames human activities.

<p>Human interactions with white-tailed deer (<em>Odocoileus virginianus</em>) continue to change across the U.S. The growth of deer populations and urbanization of human populations have shifted values for wildlife away from traditional use toward mutual coexistence while simultaneously providing habitat for deer to thrive.<strong> </strong>Still, a mismatch exists between the reality of human-deer interactions and the management of them. Despite a changing social landscape, the human dimensions of deer management remain focused on hunting interests and the mitigation of crop damage to agricultural producers. Amid a national push to broaden wildlife ‘stakeholders’ to encompass all potential beneficiaries of wildlife, state wildlife agencies need to assess the needs and concerns of the broader public they serve to determine whether and how to engage non-traditional groups in wildlife management planning.</p> <p>Recognizing these needs, the Indiana Department of Natural Resources (IN-DNR) partnered with Purdue University in 2018 to initiate the Integrated Deer Management Project (IDMP). As part of the IDMP, this dissertation comprises the first empirical assessment of social perceptions of white-tailed deer across Indiana. My research aimed to: (i) examine the initial context of human-deer interactions in Indiana and identify key social and cognitive factors that shape them; (ii) investigate how emotions, an understudied construct, interact with beliefs and attitudes to influence resident judgements about deer management; (iii) understand existing levels of satisfaction with deer management, potentials for social conflict over management approaches, and their social-ecological drivers; and (iv) develop indices and tools that can help IN-DNR officials better account for social perceptions and concerns in deer management planning. Due to a lack of prior knowledge about human-deer interactions in the state, I used an exploratory mixed-methods research design to address these objectives. I began by conducting 59 semi-structured interviews with residents around Indiana and two focus groups in the city of Bloomington (n=14) to understand their existing perceptions, beliefs, attitudes, and emotions related to deer and deer management. These interviews informed the development of a quantitative survey which I distributed to 6,000 residents across the state. I received 1806 completed surveys for a response rate of 33%.</p> <p>My data show that social perceptions of deer and deer management remain complex, driven by dynamic feedbacks among emotions, personal experiences, livelihood and behavioral contexts, beliefs about deer management, and beliefs about other social groups. I found that mixed emotions, situational contexts, and perceived power imbalances play key roles in shaping and shifting deer-related cognitions, yet models of cognitive processing, and human-wildlife interactions more broadly, neglect these dynamics. Emotions, specifically, have been marginalized by researchers and practitioners, likely due to the perception that they represent irrational reactions rather than calculated judgements. Under different scenarios of encountering deer, however, I found that respondent emotions exert a mediating effect on their judgments about deer management, and that the type of deer encountered matters. Emotions thus work together with cognitions to process various stimuli in a human-wildlife encounter and reach a normative decision. I posit that understanding when and why emotional responses arise will help practitioners develop more effective and socially accepted approaches to wildlife management.</p> <p>I next developed and analyzed indices of public satisfaction with the IN-DNR and potentials for social conflict over deer management approaches. I found that public satisfaction with deer management is nuanced and multidimensional. Cognitive variables like residents’ perceived acceptability of management methods and their deer-related concerns most strongly predicted agency performance and quality measures of satisfaction, whereas demographic characteristics including self-identity, wildlife value orientation, and allowance of hunting on one’s property exerted the strongest influences on trust components of satisfaction. Future studies should advance a multidimensional conception of satisfaction and associate it with key variables that I suspect underly satisfaction but were not captured in this study: perceived control, psychological distance, and norms of knowledge exchange between wildlife agencies and the public. Next, I found that potentials for social conflict over deer management varied with resident self-identities and management methods but showed more predictable variation with political ideologies. Geographically, hotspots of social conflict clustered around urban areas, indicating that cities and their residents should serve as a focus for public engagement efforts and mixed management strategies. Expanding agency conceptions of public satisfaction and social conflict represents a critical step towards broadening support for wildlife management and practicing good wildlife governance.<strong> </strong>I conclude by discussing barriers to integrating social and ecological data and the practicality of incorporating complex social dimensions into wildlife management planning.</p>

A study was conducted to determine what impact high white-tailed deer (Odocoileus virginianus) densities were having on the native grasslands of a tallgrass: aspen forest tract embedded within an agro-urban setting. Due to excessive spring moisture, row-crops were unavailable the first year. Using microhistological fecal analysis to determine dietary composition, deer were assessed to be placing the site’s favoured native plant species at risk of extirpation. Measuring woody stem abundance and height along and near the prairie: forest ecotone, deer were found to restructure woody growth but not directly influence encroachment rates. Indirectly, however, deer facilitated forest encroachment and prairie degradation through seed dispersal, nitrogen deposition, gap-dynamics, and trampling. Comparing dietary composition to nutritional data, deer grazed to maximize fitness, selecting foods high in IVDMD, minimizing energy expenditure, and optimizing CP. High crop CP was offset by intensively grazing particular native plants. ADF was an effective nutritional marker, not AIA.

A study was conducted to determine what impact high white-tailed deer (Odocoileus virginianus) densities were having on the native grasslands of a tallgrass: aspen forest tract embedded within an agro-urban setting. Due to excessive spring moisture, row-crops were unavailable the first year. Using microhistological fecal analysis to determine dietary composition, deer were assessed to be placing the site’s favoured native plant species at risk of extirpation. Measuring woody stem abundance and height along and near the prairie: forest ecotone, deer were found to restructure woody growth but not directly influence encroachment rates. Indirectly, however, deer facilitated forest encroachment and prairie degradation through seed dispersal, nitrogen deposition, gap-dynamics, and trampling. Comparing dietary composition to nutritional data, deer grazed to maximize fitness, selecting foods high in IVDMD, minimizing energy expenditure, and optimizing CP. High crop CP was offset by intensively grazing particular native plants. ADF was an effective nutritional marker, not AIA.