Wetland density is believed to be an important determinant of home range size variation in mallards (Anas platyrhynchos), but hypothesized effects of upland habitat and female size and age have not been adequately evaluated. Thus, I investigated correlates and consequences of home range size variation using radio-tracking data for 131 female mallards studied on 12 Canadian prairie parkland sites, 1995-1998. Home range size and habitat composition varied within and among study areas; overall, home range size variation was best modeled to include effects of seasonal and semi-permanent wetlands (β = -0.06 ± 0.01 SE) and wood-shrub habitat (β = -0.03 ± 0.01 SE). Contrary to predictions, I obtained no support for a positive association between home range size and female body size or a negative relationship between home range size and female age. After controlling effects of wetland density, mean home range sizes were larger on study areas with lower mallard breeding pair densities. I suspect that individual home ranges were smaller in areas of high pair density because of increased intraspecific competition for breeding space. A higher proportion of wood-shrub habitat may have contributed to smaller individual home range sizes because of greater relative availability of preferred nesting habitat. Likewise, a high proportion of wetlands in home ranges could enhance access to important resources such as food, leading to smaller home range sizes.<p> Reproductive and survival consequences were investigated using 8 variables to distinguish between three reproductive categories (females that either did not nest, nested but failed, or nested successfully) and two survival categories (dead versus alive) with discriminant function analysis. Successful females were clearly separated from non-nesting females by having smaller home ranges (95% kernel estimate) with higher percentages of wood-shrub and habitat treatment but lower percentages of seasonal and semi-permanent wetlands. Females that did not nest were further distinguished from nesting females by being younger, structurally smaller and having larger home ranges composed of higher percentages of seasonal and semi-permanent wetlands. Date of first nesting (standardized by study area) was not associated with home range composition. Survival was also unrelated to either home range composition or female attributes. Overall, breeding performance was better described by variation in landscape characteristics than by female attributes, a finding that is consistent with other recent evidence from breeding ducks.

Wetland density is believed to be an important determinant of home range size variation in mallards (Anas platyrhynchos), but hypothesized effects of upland habitat and female size and age have not been adequately evaluated. Thus, I investigated correlates and consequences of home range size variation using radio-tracking data for 131 female mallards studied on 12 Canadian prairie parkland sites, 1995-1998. Home range size and habitat composition varied within and among study areas; overall, home range size variation was best modeled to include effects of seasonal and semi-permanent wetlands (β = -0.06 ± 0.01 SE) and wood-shrub habitat (β = -0.03 ± 0.01 SE). Contrary to predictions, I obtained no support for a positive association between home range size and female body size or a negative relationship between home range size and female age. After controlling effects of wetland density, mean home range sizes were larger on study areas with lower mallard breeding pair densities. I suspect that individual home ranges were smaller in areas of high pair density because of increased intraspecific competition for breeding space. A higher proportion of wood-shrub habitat may have contributed to smaller individual home range sizes because of greater relative availability of preferred nesting habitat. Likewise, a high proportion of wetlands in home ranges could enhance access to important resources such as food, leading to smaller home range sizes.<p> Reproductive and survival consequences were investigated using 8 variables to distinguish between three reproductive categories (females that either did not nest, nested but failed, or nested successfully) and two survival categories (dead versus alive) with discriminant function analysis. Successful females were clearly separated from non-nesting females by having smaller home ranges (95% kernel estimate) with higher percentages of wood-shrub and habitat treatment but lower percentages of seasonal and semi-permanent wetlands. Females that did not nest were further distinguished from nesting females by being younger, structurally smaller and having larger home ranges composed of higher percentages of seasonal and semi-permanent wetlands. Date of first nesting (standardized by study area) was not associated with home range composition. Survival was also unrelated to either home range composition or female attributes. Overall, breeding performance was better described by variation in landscape characteristics than by female attributes, a finding that is consistent with other recent evidence from breeding ducks.

<p dir="ltr">Global forest ecosystems provide essential ecosystem services that contribute to water and climate regulation, food production, recreation, and raw materials. They also serve as crucial habitats for numerous terrestrial species of amphibians, birds, and mammals worldwide. However, recent decades have witnessed unprecedented changes in forest ecosystems due to climate change, shifts in species distribution patterns, increased planted forest areas, and various disturbances such as forest fires, insect infestations, and urbanization. These changes can have far-reaching impacts on ecological networks, human well-being, and the well-being of global forest ecosystems. To address these challenges, I present four studies to quantify forest dynamics through mapping, classification, and projection, using artificial intelligence tools in combination with a vast amount of training data. (I) I present a spatially continuous map of planted forest distribution across East Asia, produced by integrating multiple sources of planted and natural forest data. I found that China contributed 87% of the total planted forest areas in East Asia, most of which are located in the lowland tropical/subtropical regions and Sichuan Basin. I also estimated the dominant genus in each planted forest location. (II) I used continent-wide forest inventory data to compare the range shifts of forest types and their constituent tree species in North America in the past 50 years. I found that forest types shifted more than three times as fast as the average of their constituent tree species. This marked difference was attributable to a predominant positive covariance between tree species ranges and the change of species relative abundance. (III) Based on individual-level field surveys of trees and breeding birds across North America, I characterized New World wood-warbler (<i>Parulidae</i>) species richness and its potential drivers. I identified forest type as the most powerful predictor of New World wood-warbler species richness, which adds valuable evidence to the ongoing physiognomy versus composition debate among ornithologists. (IV) In the appendix, I utilized continent-wide forest inventory data from North America and South America and the combination of supervised and unsupervised machine learning algorithms to produce the first data-driven map of forest types in the Americas. I revealed the distribution of forest types, which are useful for cost-effective forest and biodiversity management and planning. Taken together, these studies provide insight into the dynamics of forest ecosystems at a large geographic scale and have implications for effective decision-making in conservation, management, and global restoration programs in the midst of ongoing global change.</p>