Treesearch

Piscivory by birds can be significant, particularly on fish in small streams and during seasonal low flow when available cover from predators can be limited. Yet, how varying amounts of cover may change the extent of predation mortality from avian predators on fish is not clear. We evaluated size-selective survival of coastal cutthroat trout (Oncorhynchus clarkii clarkii) in replicated semi-natural stream sections. These sections provided high (0.01 m2 of cover per m2 of stream) or low (0.002 m2 of cover per m2 of stream) levels of instream cover available to trout and were closed to...

BACKGROUND: Economic and ecological impacts of ash (Fraxinus spp.) mortality resulting from emerald ash borer (EAB) (Agrilus planipennis Fairmaire) invasion are severe in forested, residential and urban areas. Management options include girdling ash trees to attract ovipositing adult beetles and then destroying infested trees before larvae develop or protecting ash with a highly effective, systemic emamectin benzoate insecticide. Injecting this insecticide and then girdling injected trees a few weeks later could effectively create lethal trap trees, similar to a bait-and-kill tactic, if...

Over large areas, synchronous fluctuations in population density are often attributed to environmental stochasticity (e.g., weather) shared among local populations. This concept was first advanced by Patrick Moran who showed, based on several assumptions, that long-term population synchrony will equal the synchrony of environmental stochasticity among locations. We examine the consequences of violating one of Moran's assumptions, namely that environmental synchrony is constant through time. We demonstrate that the synchrony of weather conditions from regions across the United States varied...

Aim We examined species composition of urban forests from local to global scales using occurrence and abundance information to determine how compositional similarity is defined across spatial scales. We predicted that urban forests have become more homogeneous world-wide, which should result in minimal scale dependence that is more pronounced for non-native species, especially when considering abundance information.

Information on street trees is critical for management of this important resource. Sampling of street tree populations provides an efficient means to obtain street tree population information. Long-term repeat measures of street tree samples supply additional information on street tree changes and can be used to report damages from catastrophic events. Analyses of several street tree populations reveal that a 2%-3% sample of block segments with known length within a city will likely produce estimates on the total number of trees with a standard error around 10% of the total population...

Disturbance-dependent habitats such as grasslands and shrublands are declining in many regions. To mitigate these declines, government agencies are using anthropogenic disturbances like logging and mowing to mimic natural ones. Because these programs can be costly or controversial, measuring their effectiveness is important. Here, we evaluate the conservation effectiveness of shrubland management for 15 bird species in Massachusetts, USA. Because shrublands are constantly changing in extent and location, we suggest that the key measure of conservation effectiveness should be how managed...

Shrubland birds have experienced widespread declines in the eastern United States. Habitat for shrubland birds is typically dynamic, in which available habitat changes temporally and spatially in response to disturbance and succession. Despite widespread concerns among conservationists about shrubland birds, much is still poorly understood regarding fundamental demographic processes associated with the persistence of species in dynamic landscapes, such as the age of colonists, their success upon establishment, the fate of birds displaced by disturbance, and the effect of displaced birds on...

Continental-scale monitoring programs with standardized survey protocols play an important role in conservation science by identifying species in decline and prioritizing conservation action. However, rare, inaccessible, or spatially fragmented communities may be underrepresented in continental-scale surveys. Data on these communities often come from decentralized, local monitoring efforts that differ in their goals and survey protocols. We combine 16 point count datasets, controlling for differences in protocol and detection probabilities to estimate regional trends for 14 spruce-fir...

The terrestrial biosphere is currently a strong carbon (C) sink but may switch to a source in the 21st century as climate-driven losses exceed CO2-driven C gains, thereby accelerating global warming. Although it has long been recognized that tropical climate plays a critical role in regulating interannual climate variability, the causal link between changes in temperature and precipitation and terrestrial processes remains uncertain. Here, we combine atmospheric mass balance, remote sensing-modeled datasets of vegetation C uptake, and climate datasets to characterize the temporal variabilit...

In seasonal plant communities where water availability changes dramatically both between and within seasons, understanding the mechanisms that enable plants to exploit water pulses and to survive drought periods is crucial. By measuring rates of physiological processes, we examined the trade-off between water exploitation and drought tolerance among seedlings of trees of a tropical dry forest, and identified biophysical traits most closely associated with plant water-use strategies. We also explored whether early and late secondary successional species occupy different portions of trade-off...