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Little is known about how positive biotic interactions structure animal communities. Nest association is a common reproductive facilitation in which associate species spawn in nests constructed by host species. Nest-associative behaviour is nearly obligate for some species, but facultative for others; this can complicate interaction network topology. Nest(More)
Lotic fish have developed life history strategies adapted to the natural variation in stream flow regimes. The natural timing, duration, and magnitude of flow events has contributed to the diversity, production, and composition of fish assemblages over time. Studies evaluating the role of hydrology in structuring fish assemblages have been more common at(More)
A common theme in recent landscape studies is the comparison of riparian and watershed land use as predictors of stream health. The objective of this study was to compare the performance of reach-scale habitat and remotely assessed watershed-scale habitat as predictors of stream health over varying spatial extents. Stream health was measured with scores on(More)
Conserving rare species and protecting biodiversity and ecosystem functioning depends on sound information on the nature of rarity. Rarity is multidimensional and has a variety of definitions, which presents the need for a quantitative classification scheme with which to categorize species as rare or common. We constructed such a classification for North(More)
An understanding of the spatial variation in the population structure of lotic fishes is vital to their conservation. Population level approaches may be more suitable than community level approaches for identifying stream fish response to urbanization. Lithophilic (clean mineral substrate) spawners are disproportionally affected by common habitat(More)
Biological assessment of aquatic ecosystems is widely employed as an alternative or complement to chemical and toxicity testing due to numerous advantages of using biota to determine ecosystem condition. These advantages, especially to developing countries, include the relatively low cost and technical requirements. This study was conducted to determine the(More)
The development of encompassing general models of ecology is precluded by underrepresentation of certain taxa and systems. Models predicting context-dependent outcomes of biotic interactions have been tested using plants and bacteria, but their applicability to higher taxa is largely unknown.We examined context dependency in a reproductive mutualism between(More)
Two genetically improved tilapia strains (GIFT and Akosombo) have been created with Oreochromis niloticus (Nile tilapia), which is native to Africa. In particular, GIFT has been shown to be significantly superior to local African tilapia strains in terms of growth rate. While development economists see the potential for food security and poverty reduction(More)
Riverine flooding is a significant global issue. Although it is well documented that the influence of landscape structure on floods decreases as flood size increases, studies that define a threshold flood-return period, above which landscape features such as topography, land cover and impoundments can curtail floods, are lacking. Further, the relative(More)