Consequences of within population variation have recently attracted an increased interest in evolutionary ecology research. Theoretical models suggest important population-level consequences, but many of these predictions still remain to be tested. These issues are important for a deepened understanding of population performances and persistence, especially in a world characterized by rapid fragmentation of natural habitats and other environmental changes. I review theoretical models of consequences from intra population genetic and phenotypic variation. I find that more variable populations are predicted to be characterized by broader resource use, reduced intraspecific competition, reduced vulnerability to environmental changes, more stable population dynamics, higher invasive potential, enhanced colonization and establishment success, larger distribution ranges, higher evolvability, higher productivity, faster population growth rate, decreased extinction risk, and higher speciation rate, compared with less variable populations. To test some of these predictions I performed experiments and compared how different degree of colour polymorphism influences predation risk and establishment success in small groups. My comparisons of predation risk in mono- and polymorphic artificial prey populations showed that the risk of being eaten by birds does not only depend on the coloration of the individual prey item itself, but also on the coloration of the other members of the group. Two experiments on establishment success in small founder groups of Tetrix subulata pygmy grasshoppers with different degree of colour morph diversity show that establishment success increases with higher degree of diversity, both under controlled conditions in outdoor enclosures and in the wild. These findings may be important for re-stocking of declining populations or re-introductions of locally extinct populations in conservation biology projects. I report on remarkably rapid evolutionary shifts in colour morph frequencies in response to the changed environmental conditions in replicated natural populations of pygmy grasshoppers in fire ravaged areas. This finding 1 illustrates the high adaptive potential in a polymorphic species, and indicates the importance of preserved within-species diversity for evolutionary rescue. Finally, I review if theoretical predictions are supported by other published empirical tests and find strong support for the predictions that more variable groups benefit from reduced vulnerability to environmental changes, reduced population fluctuations and extinction risk, larger distribution ranges, and higher colonization or establishment success. In conclusion, my thesis illustrates how within-population variation influences ecological and evolutionary performances of populations both in the short and long term. As such, it emphasizes the need for conservation of biodiversity also within populations.

Tall fescue grasslands are the dominant form of grasslands in the North American transition zone, however, warm-season forages provide necessary forage for livestock in the summer. Pollinators require steady forage availability in the same fashion as cattle. Native warm-season grasses (NWSG) and wildflowers (WF) could be incorporated into tall fescue (TF) grasslands to improve pollinator resources within agricultural landscapes without sacrificing livestock production. This balance of ecosystem services can be considered bee-friendly beef. Previous establishment experiments suggests that bee-friendly beef is a possibility, although establishment and persistence of NWSG-WF stands warrants additional research. Three small plot experiments were conducted to evaluate different planting methods designed to optimize establishment of NWSG-WF stands. Additionally, a grazing study examined whether NWSG-WF pasture enhancement could improve animal performance in TF grazing systems. The small plot experiments experienced extreme weed competition in the establishment year, although plots with higher NWSG content had fewer weeds over time. Floral production was comparable across treatment, which suggests lower WF seeding rates can generate comparable pollinator resources. Major findings from these experiments suggested that spatial or temporal separation of NWSGWF was unnecessary to generate successful establishment, varying the ratio of NWSG-WF in seed mixtures produced similar establishment outcomes, and that adding companion crops to NWSG-WF mixtures did not improve establishment success appreciably. In the grazing experiment, animal performance was improved in the biodiverse grazing systems when heifers 3 had access to the NWSG. Biodiverse and shaded grazing systems modified animal behavior and reduced body temperature relative to control grazing systems, although only biodiverse grazing systems improved animal performance. Native WF species failed to establish within the biodiverse grazing system, but white clover provided all subsequent floral production. Establishing WF in pastures is challenging and warrants additional study on more effective weed control strategies and systems to ensure establishment success. Selecting WF for agronomic performance or breeding such plant material will be necessary to improve emergence and establishment dynamics. Ideally trait data can identify the optimal WF species for specific grazing systems. Biodiverse NWSG-WF can be highly effective at improving summer weight gain in beef cattle. Future studies should focus on finding a more optimal balance of NWSG, WF, and TF that can benefit beef cattle production, pollinator services, and ecosystem services regarding soil and water quality, as well as pasture resiliency to dynamic conditions. / Doctor of Philosophy / Tall fescue grasslands are the dominant form of grasslands in the North American transition zone, however, warm-season forages provide necessary forage for livestock in the summer. Pollinators require steady forage availability in the same fashion as cattle. Native warm-season grasses (NWSG) and wildflowers (WF) could be incorporated into tall fescue (TF) grasslands to improve pollinator resources within agricultural landscapes without sacrificing livestock production. This balance of ecosystem services can be considered bee-friendly beef. Previous establishment experiments suggests that bee-friendly beef is a possibility, although establishment and persistence of NWSG-WF stands warrants additional research. Three small plot experiments were conducted to evaluate different planting methods designed to optimize establishment of NWSG-WF stands. Additionally, a grazing study examined whether NWSG-WF pasture enhancement could improve animal performance in TF grazing systems. The small plot experiments experienced extreme weed competition in the establishment year, although plots with higher NWSG content had fewer weeds over time. Floral production was comparable across treatment, which suggests lower WF seeding rates can generate comparable pollinator resources. Major findings from these experiments suggested that spatial or temporal separation of NWSGWF was unnecessary to generate successful establishment, varying the ratio of NWSG-WF in seed mixtures produced similar establishment outcomes, and that adding companion crops to NWSG-WF mixtures did not improve establishment success appreciably. In the grazing experiment, animal performance was improved in the biodiverse grazing systems when heifers 3 had access to the NWSG. Biodiverse and shaded grazing systems modified animal behavior and reduced body temperature relative to control grazing systems, although only biodiverse grazing systems improved animal performance. Native WF species failed to establish within the biodiverse grazing system, but white clover provided all subsequent floral production. Establishing WF in pastures is challenging and warrants additional study on more effective weed control strategies and systems to ensure establishment success. Selecting WF for agronomic performance or breeding such plant material will be necessary to improve emergence and establishment dynamics. Ideally trait data can identify the optimal WF species for specific grazing systems. Biodiverse NWSG-WF can be highly effective at improving summer weight gain in beef cattle. Future studies should focus on finding a more optimal balance of NWSG, WF, and TF that can benefit beef cattle production, pollinator services, and ecosystem services regarding soil and water quality, as well as pasture resiliency to dynamic conditions.

To refine our knowledge and to adequately test hypotheses concerning theoretical and applied aspects of invasion biology, successful and unsuccessful invaders should be compared. This study investigated insect establishment patterns by comparing the climatic preferences and biological attributes of two groups of polyphagous insect species that are constantly intercepted at New Zealand's border. One group of species is established in New Zealand (n = 15), the other group comprised species that are not established (n = 21). In the present study the two groups were considered to represent successful and unsuccessful invaders. To provide background for interpretation of results of the comparative analysis, global areas that are climatically analogous to sites in New Zealand were identified by an eco-climatic assessment model, CLIMEX, to determine possible sources of insect pest invasion. It was found that south east Australia is one of the regions that are climatically very similar to New Zealand. Furthermore, New Zealand shares 90% of its insect pest species with that region. South east Australia has close trade and tourism links with New Zealand and because of its proximity a new incursion in that analogous climate should alert biosecurity authorities in New Zealand. Other regions in western Europe and the east coast of the United States are also climatically similar and share a high proportion of pest species with New Zealand. Principal component analysis was used to investigate patterns in insect global distributions of the two groups of species in relation to climate. Climate variables were reduced to temperature and moisture based principal components defining four climate regions, that were identified in the present study as, warm/dry, warm/wet, cool/dry and cool/moist. Most of the insect species established in New Zealand had a wide distribution in all four climate regions defined by the principal components and their global distributions overlapped into the cool/moist, temperate climate where all the New Zealand sites belong. The insect species that have not established in New Zealand had narrow distributions within the warm/wet, tropical climates. Discriminant analysis was then used to identify which climate variables best discriminate between species presence/absence at a site in relation to climate. The discriminant analysis classified the presence and absence of most insect species significantly better than chance. Late spring and early summer temperatures correctly classified a high proportion of sites where many insect species were present. Soil moisture and winter rainfall were less effective discriminating the presence of the insect species studied here. Biological attributes were compared between the two groups of species. It was found that the species established in New Zealand had a significantly wider host plant range than species that have not established. The lower developmental threshold temperature was on average, 4°C lower for established species compared with non-established species. These data suggest that species that establish well in New Zealand have a wide host range and can tolerate lower temperatures compared with those that have not established. No firm conclusions could be drawn about the importance of propagule pressure, body size, fecundity or phylogeny for successful establishment because data availability constrained sample sizes and the data were highly variable. The predictive capacity of a new tool that has potential for eco-climatic assessment, the artificial neural network (ANN), was compared with other well used models. Using climate variables as predictors, artificial neural network predictions were compared with binary logistic regression and CLIMEX. Using bootstrapping, artificial neural networks predicted insect presence and absence significantly better than the binary logistic regression model. When model prediction success was assessed by the kappa statistic there were also significant differences in prediction performance between the two groups of study insects. For established species, the models were able to provide predictions that were in moderate agreement with the observed data. For non-established species, model predictions were on average only slightly better than chance. The predictions of CLIMEX and artificial neural networks when given novel data, were difficult to compare because both models have different theoretical bases and different climate databases. However, it is clear that both models have potential to give insights into invasive species distributions. Finally the results of the studies in this thesis were drawn together to provide a framework for a prototype pest risk assessment decision support system. Future research is needed to refine the analyses and models that are the components of this system.