Treesearch

Advances in wildlife telemetry and remote sensing technology facilitate studies of broad-scale movements of ungulates in relation to phenological shifts in vegetation. In tropical island dry landscapes, home range use and movements of non-native feral goats (Capra hircus) are largely unknown, yet this information is important to help guide the conservation and restoration of some of the world’s most critically endangered ecosystems. We hypothesized that feral goats would respond to resource pulses in vegetation by traveling to areas of recent green-up. To address this hypothesis, we fitted...

To be successful, prescriptions for tropical forest restoration should facilitate natural recovery while also being easy to implement and inexpensive. In the Lake Ngardok Nature Reserve, Palau, we monitored native forest patches (4–275 m2) over 3 years to assess the influence of several low-cost restoration methods on patch expansion, growth of naturally established tree saplings, density of naturally establishing tree seedlings, growth of planted tree seedlings, flower and fruit production, and bird and flying fox visitations. Treatments included fertilization, trimming of surrounding...

Hawai‘i has served as a model system for studies of nutrient cycling and conservation biology. The islands may also become a laboratory for exploring new approaches to forest restoration because of a common history of degradation and the growing number of restoration projects undertaken. Approximately half of the native ecosystems of Hawai‘i have been converted to non-native conditions. Many restoration projects have focused on intensively managed out plantings of native plants with emphasis on threatened and endangered species. While these projects have been effective in stabilizing plant...

In this study we examined historic drought frequency and hydrologic effects of removing invasive plants from one of the few remaining Hawaiian wet lowland forests, near Hilo, Hawai‘i. We developed a conceptual and statistical model of Hilo droughts using historic rainfall and pan evaporation data and discovered that episodes of low soil moisture were most likely from January to March but also occurred in June or July. Field measurements were taken in four pairs of plots. Nonnative woody and herbaceous species were removed from four plots; control plots were undisturbed. Soil water potential...

Ecosystem restoration efforts are carried out by a variety of individuals and organizations with an equally varied set of goals, priorities, resources and time-scales. Once restoration of a degraded landscape or community is recognized as necessary, choosing which species to include in a restoration programme can be a difficult and value-laden process (Fry, Power & Manning 2013; Jones 2013). Species choice in restoration is often carried out with limited ecological information, particularly in regard to species interactions, successional processes and resource-use patterns. Selecting...

The storage and flow of carbon (C) into and out of forests can differ under the influence of dominant tree species because of species-based variation in C production, decomposition, retention, and harvest-based export. Following abandonment of agricultural activities in the first half of the 20th century, many landscapes of the Great Lakes region (USA) were planted to red pine (Pinus resinosa) or naturally regenerated to northern hardwood species including sugar maple (Acer saccharum), red oak (Quercus rubra) and red maple (Acer rubrum). We located eight pairs of adjacent, similarly aged...

Four 10- to 20-year-old plantations were precommercially thinned to determine the effects on tree growth and mortality caused by armillaria and heterobasidion root diseases. The plantations represented different species compositions with one each of (1) coastal Douglas-fir and noble fir, (2) Douglas-fir and western hemlock, (3) pure Douglas-fir, and (4) Shasta red fir and mountain hemlock. After 30 years, the probabilities of leave-tree survival and actual leave-tree survival (trees/ha [TPH]) were significantly (P ≤ 0.05) higher in thinned versus unthinned plots in one of the four plantatio...

The influence of Native American land-use practices on vegetation composition and structure has long been a subject of significant debate. This is particularly true in portions of the western United States where tribal hunter-gatherers did not use agriculture to meet subsistence and other cultural needs. Climate has been viewed as the dominant determinant of vegetation structure and composition change over time, but ethnographic and anthropological evidence suggests that Native American land-use practices (particularly through the use of fire) had significant landscape effects on vegetation...

We used measurements from airborne imaging spectroscopy and LiDAR to quantify the biophysical structure and composition of vegetation on a dryland substrate age gradient in Hawaii. Both vertical stature and species composition changed during primary succession, and reveal a progressive increase in vertical stature on younger substrates followed by a collapse on Pleistocene-aged flows. Tall-stature Metrosideros polymorpha woodlands dominated on the youngest substrates (hundreds of years), and were replaced by the tall-stature endemic tree species Myoporum sandwicense and Sophora chrysophylla...

Atmospheric deposition of nitrogen (N), sulfur (S), and base cations was measured across the network of jack pine sites in the Athabasca Oil Sands Region using ion exchange resin (IER) collectors. Deposition was measured in forest clearings (bulk deposition) and under jack pine canopies (throughfall). As noted previously for other pollutants, throughfall deposition of NO3-N and NH4-N decreased exponentially within a 20-25 km zone surrounding the industrial center. At a distance of 20 km from the industrial center N deposition decreased by 88%, while S and base cations decreased by 56 and...