Treesearch

Salt tolerance of agricultural crops has been studied since the 1940, but knowledge regarding salt tolerance of woody crops is still in its initial phase. Salt tolerance of agricultural crops has been expressed as the yield decrease due to a certain salt concentration within the root zone as compared to a non-saline control. The most well-known plant response curve to salinity has been a piece-wise linear regression relating crop yield to root zone salinity. This method used the hypothesis that crops tolerate salt up to a threshold after which their yield decreases approximately linearly....

Recent warming at high latitudes has accelerated permafrost thaw, which can modify soil carbon dynamics and watershed hydrology. The flux and composition of dissolved organic matter (DOM) from soils to rivers are sensitive to permafrost configuration and its impact on subsurface hydrology and groundwater discharge. Here, we evaluate the utility of DOM composition and age as a tool for detecting permafrost thaw in three rivers (Beaver, Birch, and Hess Creeks) within the discontinuous permafrost zone of interior Alaska. We observed strong temporal controls on Δ14C content of hydrophobic acid...

Background: Refined estimation of carbon (C) stocks within forest ecosystems is a critical component of efforts to reduce greenhouse gas emissions and mitigate the effects of projected climate change through forest C management. Specifically, belowground C stocks are currently estimated in the United States' national greenhouse gas inventory (US NGHGI) using nationally consistent species- and diameter-specific equations applied to individual trees. Recent scientific evidence has pointed to the importance of climate as a driver of belowground C stocks. This study estimates belowground C...

The production of pyrogenic carbon (PyC; a continuum of organic carbon (C) ranging from partially charred biomass and charcoal to soot) is a widely acknowledged C sink, with the latest estimates indicating that ~50% of the PyC produced by vegetation fires potentially sequesters C over centuries. Nevertheless, the quantitative importance of PyC in the global C balance remains contentious, and therefore, PyC is rarely considered in global C cycle and climate studies. Here we examine the robustness of existing evidence and identify the main research gaps in the production, fluxes and fate of...

Among the various animal taxa that are have established outside their native ranges, invasions by insect species are the most numerous worldwide. In order to better understand the characteristics of insect species that make them more invasion prone, the characteristics of habitats that make them more susceptible to invasions and to understand the pathways that facilitate invasions, we compared the compositions of the native and non-native insect communities among five Pacific regions: North America, the Hawaiian Islands, mainland Japan, Ogasawara and Okinawa Islands. These regions comprise...

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...

South Africa is one of the most biodiversity-rich countries in the world, with much valuable biodiversity situated on a range of different land tenure types, including state, private and communal land. Despite this, these wild lands are being lost at an unprecedented rate, with the resultant loss of natural areas and associated ecosystem services. The challenge lies in the need to protect the unique biodiversity, by integrating the development needs of poverty-stricken communities with the need to secure the remaining natural wild places, and thereby secure the very areas on which these...

The Wilderness Foundation, in partnership with South African National Parks has initiated a two year project in the Karoo; The Mountain Zebra-Camdeboo Corridor Project. Through either voluntary Contractual National Park or Protected Environment agreements, the project aims to work with, rather than displace, current conservation-compatible land-use practices such as ecotourism, livestock grazing and other sustainable resource use. Less formal conservation options, such as biodiversity agreements, will also be offered to landowners. These agreements provide benefits to landowners in terms...

We have demonstrated the use of an advanced Gaussian-Process (GP) emulator to estimate wildland fire emissions over a wide range of fuel and atmospheric conditions. The Fire Emission Production Simulator, or FEPS, is used to produce an initial set of emissions data that correspond to some selected values in the domain of the input fuel and atmospheric parameters for the purpose of training the emulator. The emulated emissions are found to be within ±5% of the FEPS simulated emissions, providing confidence in the potential use of the GP-emulator for this and other similar applications....

The winter moth (Operophtera brumata L.; Lepidoptera: Geometridae) is an inchworm caterpillar that hatches coincident with bud-break on its hosts and feeds on a wide range of deciduous trees. It is one of a group of geometrid species that feed in early spring and then pupate in the top layer of the soil or litter beginning in mid-May. As postulated by Feeney (1970), the early spring feeding strategy of such larvae allows them to take advantage of the high nitrogen content and low concentrations of defensive compounds, such as condensed tannins, in newly formed leaves.