Master of Science / Biology / David A. Haukos / The lesser prairie-chicken (Tympanuchus pallidicinctus) has experienced range-wide population declines and range contraction since European settlement. Due to ongoing declines, lesser prairie-chickens were listed as threatened under the Endangered Species Act in 2014; however, uncertainty regarding the legal status of the species has developed following a judicial decision to vacate the listing in September 2015. Regardless, new research is required for conservation planning, especially for understudied portions and temporal periods of the occupied range. I evaluated nonbreeding lesser prairie-chicken survival using known-fate models, and tested for the influence of environmental, landscape and predator effects on weekly survival. I estimated nonbreeding home-range size using fixed kernel density estimators and Brownian Bridge movement models for VHF and Satellite tagged lesser prairie-chickens, and measured habitat use during the 6-month nonbreeding period (16 September – 14 March). I also determined the influence of lek location on space use intensity within home ranges using resource utilization functions. Female survival was high (0.75, SE = 0.05) and consistent across nonbreeding seasons, but not explainable by selected variables. Mean home range size for birds with GPS transmitters (955 ha, SE = 128.5) was 215% larger than for individuals with VHF transmitters (303 ha, SE = 24.1) and 136% greater during the 2014-2015 nonbreeding season than the 2013-2014 season. Males and females were tied to leks throughout the nonbreeding season, and this relationship was not variable across the months of the nonbreeding season. Proportions of habitat used differed among study sites, but temporal trends were not evident. Lesser prairie-chickens exhibited consistency among ecoregions for home-range, space use, and survival; however, with differing habitat use among regions, management should be on the regional scale. Agriculture and energy development have caused fragmentation of the landscape where lesser prairie-chickens evolved. I used known fate survival models to test if landscape composition or configuration within sites caused survival to differ by site, as well as within home ranges to determine if functional relationships exist between weekly survival and landscape configuration or composition. I used Andersen-Gill models to test whether distance to anthropogenic features affected hazard rates. Differences in survival rates between sites, with survival rates 50% greater in Clark County, Kansas compared to Northwestern, Kansas, corresponded to differences in the amount of grassland habitat on the landscape, but study-site configuration was not measurably different. Increasing the number of patch types within home ranges increased survival, indicating positive effects of heterogeneity. In addition, as distance to fences decreased, lesser prairie-chickens experienced greater risk. Overall, further breakup of grassland landscapes that lesser prairie-chickens occupy should be avoided, to avoid habitat loss and fragmentation thresholds that could further affect survival rates. Additionally, fences should be removed or avoided around active leks.

<p>White-tailed deer (Odocoileus virginianus; hereafter deer) are a keystone herbivore within forest ecosystems. While deer rely on plant species for growth, reproduction, and survival, multiple external factors can dictate browsing behavior. These factors ultimately drive browsing selection, browsing intensity, and diet composition, which in turn can shape the influence deer have on forest ecosystems. To better understand the complex relationship between deer populations, their habitat, and public perception of deer, the Indiana Department of Natural Resources partnered with Purdue University to initiate the Integrated Deer Management Project (IDMP). As part of the IDMP, this dissertation evaluated the ecological condition of deer habitat to assess the influence deer have on woody and herbaceous plant species within Indiana forests. Our study aimed to i) rank woody species according to their selection by deer and evaluate how the ranking of individual species varies across the state (Chapter 2); ii) evaluate variables and spatial extents associated with differences in browsing intensity, and evaluate different indices used to assess differences in browsing intensity (Chapter 3); iii) quantify winter deer diet composition using DNA barcoding to evaluate how diets vary across a gradient of deer densities, browsing intensities, non-native plant densities, and landscape characteristics (Chapter 4); and iv) evaluate the interactive effects of deer, non-native plant species, and landscape characteristics on the herbaceous layer of forests, while further evaluating the spatial extent at which landscape characteristics are most strongly related to herbaceous-layer composition and diversity (Chapter 5). To do this, I sampled 152 woodlots over three years across three regions of Indiana, collecting data on the browsing selection of individual woody species, the browsing intensities on all woody species, and the composition of vegetation communities (Chapters 2, 3, and 5, respectively). To address diet composition (Chapter 4), we collected deer pellet groups to analyzed diet components. We ranked a total of 63 woody species regarding their browsing selection by deer. While most of these remained consistent from region to region, 16 varied greatly in selection, as deer often showed increased selection for a given species when it resided in an area that provided greater browsing opportunities. Browsing intensity was most associated with food availability, however, it was also influenced by deer density in the region with the lowest forest cover. The twig age index of browsing intensity showed promise as the most efficient and effective index for use in Indiana woodlots. Although diet composition did not differ across regions of Indiana, we found 16 that deer consumed several uncommon taxa when the greater landscape exhibited homogenous patch composition. Similarly, deer consumed different native taxa in forested landscapes with greater deer densities in comparison to agricultural landscapes with lower deer densities. Lastly, though browsing varied within and across regions landscape characteristic, and not deer, were the most influential suite of variables. Additionally, the spatial extent at which these variables exhibited their best fit varied depending on the dependent variable being evaluated and the region of analysis. Together, our results highlight that variables ranging from the woodlot to the landscape-scale influence browsing behavior. This showcases that deer respond to variables at varying scales when browsing and in general, browse more in areas that offer the greatest benefit, whether these areas offer greater food availability or quality, or offer lower risks associated with anthropogenic development. This suggests that when managing forests for deer both woodlot and landscape context should play a role in the decision process. Although differences in browsing were observed, deer had less impact on the herbaceous layer compared to other variables we examined. This suggests that, in contemporary forests, landscape characteristics may be the drivers of changes, and species composition may reflect a long-term history of deer herbivory with less variability resulting from differences in contemporary deer abundance within and across regions.  </p>

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Les carabes et les araignées sont des auxiliaires généralistes susceptibles d'exercer un contrôle efficace des ravageurs des cultures. La structure et composition de leurs communautés, ainsi que l'efficacité du contrôle biologique, dépendent de l'hétérogénéité des paysages, et en particulier de la présence d'habitats semi-naturels. Mais le rôle de la mosaïque agricole, susceptible de présenter une forte hétérogénéité dans l'espace et dans le temps, reste aujourd'hui peu connu. L'objectif de ce travail a été d'évaluer les effets de l'hétérogénéité spatiale et temporelle des paysages agricoles sur des auxiliaires généralistes et sur le potentiel de contrôle biologique. Nous avons échantillonné les communautés de carabes et d'araignées dans des parcelles de céréales, et estimé le potentiel de prédation par des pucerons sentinelles collés sur des cartes de prédation. Nous avons caractérisé l'hétérogénéité spatiale des paysages autour des parcelles de céréales par le pourcentage d'éléments boisés et la longueur du réseau de haies, la taille moyenne des parcelles agricoles, et la diversité des cultures. Nous avons également mis au point quatre nouvelles métriques qui synthétisent différents aspects de l'hétérogénéité temporelle interannuelle des surfaces cultivées. Nos résultats montrent qu'au printemps les araignées sont plus abondantes dans les parcelles de céréales situées dans des paysages composés de petites parcelles. Au début de l'été, ces paysages favorisent également les taux de prédation de pucerons mesurés par les cartes de prédation, et l'abondance des carabes qui se reproduisent au printemps et qui hivernent en tant qu'adultes dans des habitats semi-naturels. Les carabes qui hivernent dans le sol des parcelles au stade larvaire et se reproduisent à l'automne sont quant à eux favorisés par la diversité des cultures dans le paysage. Nos résultats montrent enfin que l'hétérogénéité temporelle de la mosaïque agricole - caractérisée par les changements de la diversité de cultures au cours des cinq dernières années - favorise elle aussi certaines espèces de carabes communément rencontrées dans les parcelles agricoles (Poecilus cupreus ou Pterostichus melanarius) et susceptibles de jouer un rôle important en tant qu'auxiliaires. Ces résultats mettent en avant le rôle complémentaire des bordures de champs non cultivées et de la mosaïque des cultures pour différents groupes d'auxiliaires, et soulignent l'importance de prendre en compte l'hétérogénéité spatiale et temporelle des surfaces cultivées dans l'étude de la biodiversité des paysages agricoles. Dans le contexte de réduction des produits phytosanitaires, nos résultats suggèrent que des paysages présentant une diversité de cultures importante variable dans le temps, et des petites parcelles qui favorisent l'intrication entre les habitats semi-naturels et les cultures, sont susceptibles de favoriser les auxiliaires généralistes ainsi que le potentiel de contrôle biologique des ravageurs. / In the context of reducing pesticide use, the potential role of some arthropod groups as pest natural enemies provides them an ecological and economic interest. In particular, ground beetles and spiders are generalist predators likely to be effective biocontrol agents. Previous studies have shown that the structure and composition of their communities, as well as the effectiveness of biological control, are influenced by landscape heterogeneity, and in particular by the presence of semi-natural habitats. However, the role of the crop mosaic, which can be highly heterogeneous in space and time, have been little considered. The main objective of our study was to determine the influences of spatial and temporal heterogeneity of agricultural landscapes on generalist natural enemies and the potential for biological pest control. We sampled carabid and spider communities in winter cereal fields, and estimated biological control potential using sentinel aphids glued on predation cards. We characterized the spatial heterogeneity of the landscapes around each cereal field by 1) the amount of wooded habitats and the length of the hedgerow network, 2) the average size of the agricultural fields, and 3) crop diversity. We also proposed four new metrics that synthesize different aspects of the multi-year temporal heterogeneity of cropped areas. Our results show that in spring, landscapes characterized by small fields, and therefore by a high density of non-cropped field margins, promote spiders abundance in cereal fields. In early summer, landscapes with small fields also promote aphid predation rates and the abundance of carabid spring breeders, which overwinter as adults in semi-natural habitats. Crop diversity promotes the abundance of carabids overwintering in soils of arable fields and breeding in autumn. Our results also show that the temporal heterogeneity of the crop mosaic - characterized among other things by the changes in crop diversity over a five year period - benefits some carabid species commonly found in agricultural landscapes (such as Poecilus cupreus and Pterostichus melanarius) which are likely to play an important role as pest natural enemies. These results highlight the complementary role of the crop mosaic and the non-cropped field borders for generalist natural enemies, and show the importance of taking into account the spatial and temporal heterogeneity of the cultivated area in further ecological studies on biodiversity in agricultural landscapes. In the context of reducing pesticide use, our results suggest that landscapes with 1) a high crop diversity that change over time, and 2) small fields that promote the interspersion between crops and semi-natural habitats, are likely to promote generalist natural enemies and biological pest control.

Les abeilles sauvages (20 000 espèces à travers le monde) participent à la pollinisation de 87,5% des espèces de plantes. Le récent déclin des abeilles sauvages en Europe met en péril la viabilité du service de pollinisation. Parmi les causes de ce déclin, la diminution des surfaces d’habitats semi-naturels (e.g. les prairies permanentes), fournissant aux abeilles sauvages des ressources floristiques diversifiées, joue un rôle particulièrement important. En parallèle de cette diminution des habitats semi-naturels qui s’est opérée depuis la seconde moitié du 20ème siècle, on observe sur la même période une forte expansion de la surface de colza en Europe. Cette culture offre une ressource abondante de nectar et de pollen pendant sa période de floraison. L’objectif de cette thèse est d’évaluer quelles sont les influences de l’organisation spatiale des habitats semi-naturels et du colza sur l’abondance des abeilles sauvages, leur diversité et le service de pollinisation en prairie permanente. Pour répondre à cet objectif, plusieurs expérimentations ont été mises en œuvre dans des prairies permanentes du Parc Naturel Régional de Lorraine, pendant et après la floraison du colza. Dans un premier temps, nous avons montré que les surfaces de colza en fleur et d’habitats semi-naturels influencent l’abondance et la richesse spécifique des abeilles en prairie permanente (effets différents en fonction de leur socialité) ainsi que la distribution intra-spécifique des tailles du corps d’Andrena cineraria. Les effets du colza s’estompent quelques semaines après la floraison du colza. Dans un second temps, nous avons trouvé que l’abondance en prairies d’Andrena cineraria (une espèce dont le pic d’émergence et le nourrissage des larves coïncident avec la floraison du colza) pendant une année N est reliée positivement à la surface occupée par le colza lors de l’année N-1. Enfin, une dernière expérimentation a été menée pour comprendre l’effet du colza sur le service de pollinisation en prairie permanente. Nos résultats montrent que l’augmentation de la surface de colza dans le paysage engendre une diminution du succès reproducteur chez Cardamine pratensis, une plante sauvage fleurissant à la même période que le colza. Ce travail de thèse souligne l’influence du colza et des habitats semi-naturels sur plusieurs niveaux trophiques (pollinisateurs, plantes sauvages) et niveaux d’organisation du vivant (communauté et population) en prairie permanente / Wild bees (20 000 species worldwide) contribute to the pollination of 87.5% of angiosperm species. The decline of wild bees in Europe jeopardizes the sustainability of the pollination service. Among the causes of this decline, the diminution of the surface of semi-natural habitats (e.g. permanent grasslands), providing diverse floristic resources, plays an important role. While the surface of semi-natural habitats has reduced since the second half of the 20th century, the surface of oilseed rape has considerably increased in Europe. Oilseed rape offers a large amount of nectar and pollen during its flowering. The main objective of this study was to evaluate the influence of the spatial organization of semi-natural habitats and oilseed rape fields on the abundance of wild bees, their diversity and the pollination service in permanent grasslands. To achieve this objective, we implemented several experiments in permanent grasslands of the “Parc Naturel Régional de Lorraine”, during and after oilseed rape flowering. Firstly, we showed that the areas covered by flowering oilseed rape fields and semi-natural habitats influence the abundance and species richness of bees in permanent grasslands (different influences according to their sociality) as well as the body size intra-specific distribution of Andrena cineraria. Effects of oilseed rape disappear few weeks after oilseed rape flowering. Secondly, we found that the abundance in grasslands of Andrena cineraria (a species whose peak activity and larval feeding coincide with oilseed rape flowering period), during year N is positively related to the area covered by oilseed rape during the year N-1. Finally, a last experiment was conducted to detect potential effects of flowering oilseed rape on the pollination service in permanent grasslands. Our results showed that increasing areas of flowering oilseed rape in the landscape lead to a reduction of the reproductive success of Cardamine pratensis, a co-flowering wild plant in permanent grasslands. This study highlights the influence of oilseed rape on several trophic levels (pollinators and wild plants) and levels of organization of life (community and population) in permanent grasslands