[Truncated abstract] Spatial structuring of genetic variation is commonly observed in plant species due to limited dispersal and local adaptation. Intraspecific genetic variation has significant implications for ecological restoration because the source of seed or plants influences patterns of gene flow, and may affect performance if there is adaptive divergence among source populations. This study assessed quantitative trait variation, local adaptation and molecular variation within three common, widespread, long-lived forest tree species from south-western Australia to understand the distribution of intraspecific genetic variation and predict the consequences of seed transfer for restoration. The geographic distribution of quantitative trait variation of jarrah Eucalyptus marginata was assessed through measurement of 15-year-old trees grown in a provenance trial. Survival of trees from the northern jarrah forest was significantly higher than that of trees from southern jarrah forest provenances, where mean annual rainfall is much higher, but stem diameter at breast height (d.b.h.) of southern jarrah forest trees was greater, implying faster growth. D.b.h. of trees from within the northern jarrah forest also exhibited a positive relationship with mean annual rainfall, with maximum d.b.h. observed in trees from provenances in the high rainfall zone. These patterns may reflect selection for faster growth under high rainfall conditions or environmentally-induced parental effects. The percentage of trees bearing buds and flowers varied among latitudinal divisions. ... Neither genetic variation within nor among populations of any species could explain variation of emergence and establishment in reciprocal transplant trials. Collectively, the findings of this study suggest structuring of genetic variation in these species at a broad, rather than a very local, scale. This is expected for widespread, long-lived species, where extensive gene flow and temporal variation are likely to favour high within, relative to among, population genetic variation. However, there is evidence that the source of seed may have a significant influence on the success of restoration of these species, whether as a result of genetic variation among populations or due to other factors affecting seed quality. These results highlight the importance of integrating studies of molecular and adaptive trait variation when seeking to understand the causes and consequences of genetic variation within plant species and contribute to the development of seed sourcing practices for improved restoration success.

Southwestern Australia is unique as it contains the world’s most nutrient-impoverished soils, experiences a prolonged-summer period and the vegetation is extremely fire-prone. It is also world-renowned for its relative high level of flora biodiversity. This book focuses on the diverse range of morphological and physiological adaptations evolved by the flora to survive in the harsh Mediterranean-type climate.

Plant traits are fundamental components of the ecological strategies of plants, influencing how plants acquire and use resources. Selection pressures along environmental gradients often give rise to predictable variation leading to phenotypic variability. This variability can result from genetic differences or environmentally-induced phenotypic plasticity. Phenotypic plasticity is a key mechanism for rapid adjustment to environmental heterogeneity, potentially providing species with a greater capacity to respond to global change. This thesis explored variation in commonly measured functional traits in populations of congeneric species (Banksia baxteri, B. coccinea, B. media and B. quercifolia R.Br.: Proteaceae) along a rainfall gradient in the bio-diverse but highly threatened Mediterranean-climate ecosystem of South-Western Australia. In a series of empirical experiments I investigated the response of morphological, physiological and allocational plant traits to heat and/or drought stress. My hypothesis was that populations at the warm, dry end of the gradient would respond more favourably to heat and drought stress as demonstrated by greater homeostasis of growth and performance relative to populations from the cool, wet end of the gradient. Using a temperature gradient system species differed in their temperature dimensions for germination, optimal temperatures stimulating most rapid and complete germination and the slope of germination decline above optimal temperatures. Overall, a sharp reduction in final percentage germination occurred outside the optimal temperature range, which coincided with germination delays relative to the optimum. The temperatures causing these responses varied among species and populations. Banksia media was least vulnerable to temperature stress, B. coccinea most vulnerable. Variation in tolerance to drought in three populations of the four species was assessed using different osmotic solutions. Overall, the threshold water potential value for a significant decline, and delay, in germination was -0.25 MPa. Banksia media appeared less vulnerable to germination failure under predicted changes in rainfall patterns, whilst B. coccinea seemed most vulnerable. In a common garden, warmer soils generally resulted in significant delays and reductions in seedling emergence and reduced leaf-stem biomass allocation. Banksia quercifolia showed the greatest reproductive decline under warmed conditions, but also the smallest vegetative shift; B. coccinea exhibited the smallest reproductive decline but showed a relatively large vegetative shift. Exposing B. baxteri and B. coccinea to warm/dry conditions in a glasshouse resulted in significant declines in seedling growth and fitness-related traits relative to phenotypes grown under cool/wet conditions. The data revealed the presence of divergent ecological strategies that may lead to current co-existence in these sympatric species, however, warm/dry conditions may lead to a shift in their interactions. These investigations demonstrate the species- and population-specific nature of plant responses to gradients of environmental change. Some common responses occurred across experiments: cross-species patterns generally upheld along the gradient, but decoupling of patterns occurred at the local level. Against expectations, population variation was not reliably associated with geographical location on the rainfall gradient, suggesting that selection for local adaptation in response to water availability or other climate factors has been minimal. Nonetheless, species expressing phenotypic variation along environmental gradients may have greater capacity to respond to global change.

The publication was prepared based on information provided by 86 countries, outcomes from regional and subregional consultations and commissioned thematic studies. It includes: •an overview of definitions and concepts related to Forest Genetic Resources (FGR) and a review of their value; •a description of the main drivers of changes; •the presentation of key emerging technologies; •an analysis of the current status of FGR conservation, use and related developments; •recommendations addressing the challenges and needs. By the FAO Commission on Genetic Resources for Food and Agriculture.

One of the greatest unmet challenges in conservation biology is the genetic management of fragmented populations of threatened animal and plant species. More than a million small, isolated, population fragments of threatened species are likely suffering inbreeding depression and loss of evolutionary potential, resulting in elevated extinction risks. Although these effects can often be reversed by re-establishing gene flow between population fragments, managers very rarely do this. On the contrary, genetic methods are used mainly to document genetic differentiation among populations, with most studies concluding that genetically differentiated populations should be managed separately, thereby isolating them yet further and dooming many to eventual extinction Many small population fragments are going extinct principally for genetic reasons. Although the rapidly advancing field of molecular genetics is continually providing new tools to measure the extent of population fragmentation and its genetic consequences, adequate guidance on how to use these data for effective conservation is still lacking. This accessible, authoritative text is aimed at senior undergraduate and graduate students interested in conservation biology, conservation genetics, and wildlife management. It will also be of particular relevance to conservation practitioners and natural resource managers, as well as a broader academic audience of conservation biologists and evolutionary ecologists.