Treesearch

American Toads are the only toad species found in Wisconsin, and they are distributed throughout the state. They are a fairly large anuran, with a stout body, short limbs, and 'warty' skin that is mostly mottled browns and tans but sometimes reddish.

The geological history of Wisconsin, particularly glacial and permafrost cycles (Clayton et al. 2001, Syverson and Colgan 2004), shaped the current topography of the state. Bedrock and soil types, rivers and natural lakes, hills and valleys are all products of past environments (e.g., Rawling et al. 2008, Lytwyn 2010, Jacobs et al. 2011, Schaetzl and Attig 2013). These geological legacies, along with climatic gradients, strongly influence the modern plant and animal diversity in Wisconsin (Albert 1995, Schulte et al. 2002, Cutright et al. 2006). Furthermore, plant communities, which are a...

The Wood Turtle is arguably one of the most attractive and interesting freshwater turtles in North America. It is a medium-sized species with yellow or orange coloration on its throat and forelegs and pyramid-shaped rings on its shell. The species is primarily distributed throughout the northern half and the west-central and south-central portions of the state.

Previous studies have evaluated how changes in atmospheric nitrogen (N) inputs and climate affect stream N concentrations and fluxes, but none have synthesized data from sites around the globe. We identified variables controlling stream inorganic N concentrations and fluxes, and how they have changed, by synthesizing 20 time series ranging from 5 to 51 years of data collected from forest and grassland dominated watersheds across Europe, North America, and East Asia and across four climate types (tropical, temperate, Mediterranean, and boreal) using the International Long-Term Ecological...

Modern Arboriculture challenges us to use our minds as well as our muscles to care for trees. Part of that challenge is to properly evaluate what we see in the landscape, including the association of fungi with the trees in our care. The fungi we can readily see include a wealth of polypores, gilled mushrooms, jellies, and slime molds. We know that some of these fungi are signs of tree disease and structural weakness, while most are “along for the ride” and pose no risk to trees or the people who live around them.

Context. Brown-headed cowbirds (Molothrus ater), through brood parasitism, can exert extrinsic population growth pressures on North American songbirds. Cowbird removal programs may reduce parasitism rates on host species but can be expensive and difficult to implement throughout a host species’ breeding range. Aim. We estimated cowbird abundance and nest parasitism rates within Kirtland's warbler (Setophaga kirtlandii) primary breeding range in Michigan, USA, and determined the maximum sustainable parasitism rate for Kirtland's warblers under several spatially structured cowbird removal...

Climate models project warmer summer temperatures will increase the frequency and heat severity of droughts in temperate forests of Eastern North America. Hotter droughts are increasingly documented to affect tree growth and forest dynamics, with critical impacts on tree mortality, carbon sequestration and timber provision. The growing acknowledgement of the dominant role of drought timing on tree vulnerability to water deficit raises the issue of our limited understanding of radial growth phenology for most temperate tree species. Here, we use well-replicated dendrometer band data sampled...

The productivity of ecosystems and their capacity to support life depends on access to reactive nitrogen (N). Over the past century, humans have more than doubled the global supply of reactive N through industrial and agricultural activities. However, long-term records demonstrate that N availability is declining in many regions of the world. Reactive N inputs are not evenly distributed, and global changes—including elevated atmospheric carbon dioxide (CO2) levels and rising temperatures—are affecting ecosystem N supply relative to demand. Declining N availability is constraining primary...

Whether increased photosynthates under elevated atmospheric CO2 could translate into sustained biomass accumulation in forest trees remains uncertain. Here we demonstrate how tree radial growth is closely linked to litterfall dynamics, which enhances nitrogen recycling to support a sustained effect of CO2 fertilization on tree-ring growth. Our ten-year observations in two alpine treeline forests indicated that annual (or seasonal) stem radial increments generally had a positive relationship with the previous year's (or season's) litterfall and its associated nitrogen return and resorption....

The long-term effects of soil acidification on the development of a young aggrading Appalachian forest were examined after 21 years of continuous treatment. Beginning with a clearcut harvest in 1997, annual ammonium sulfate (N+S) and ammonium sulfate with lime (N+S+LIME) treatments were aerially applied to a developing forest. The lime treatment was designed to counteract the acidification of the nitrogen and sulfur amendments. After 21 years, the N+S and N+S+LIME treatments had little impact on total woody biomass accumulation relative to the control. There were significant differences...