Drivers of recent forest cover change in southern South America are linked to climate and CO2

Landscape Ecology - Widespread changes in forest structure and distribution have been documented in northern Patagonia over the past century. We employed LPJ-GUESS, a dynamic global...     

Conservation planning with spatially explicit models: a case for horseshoe bats in complex mountain landscapes

Context

Context Bats are considered as an ecological indicator of habitat quality due to their sensitivity to human-induced ecosystem changes. Hence, we will focus the study on two indicator species of bats as a proxy to evaluate structure and composition of the landscape to analyze anthropic pressures driving changes in patterns.

Objectives

This study develops a spatially-explicit model to highlight key habitat nodes and corridors which are integral for maintaining functional landscape connectivity for bat movement. We focus on a complex mountain landscape and two bat species: greater (Rhinolophus ferrumequinum) and lesser (Rhinolophus hipposideros) horseshoe bats which are known to be sensitive to landscape composition and configuration.

Methods

Species distribution models are used to delineate high-quality foraging habitat for each species using opportunistic ultrasonic bat data. We then performed connectivity analysis combining (modelled) suitable foraging habitat and (known) roost sites. We use graph-theory and the deviation in the probability of connectivity to quantify resilience of the landscape connectivity to perturbations.

Results

Both species were confined to lowlands (<1000 m elevation) and avoided areas with high road densities. Greater horseshoe bats were more generalist than lesser horseshoe bats which tended to be associated with broadleaved and mixed forests.

Conclusions

The spatially-explicit models obtained were proven crucial for prioritizing foraging habitats, roost sites and key corridors for conservation. Hence, our results are being used by key stakeholders to help integrate conservation measures into forest management and conservation planning at the regional level. The approach used can be integrated into conservation initiatives elsewhere.

     

Dryland plant biomass and soil carbon and nitrogen fractions on transient land as influenced by tillage and crop rotation

Soil and crop management practices may alter the quantity, quality, and placement of plant residues that influence soil C and N fractions. We examined the effects of two tillage practices [conventional till (CT) and no-till (NT)] and five crop rotations [continuous spring wheat (Triticum aestivum L.) (CW), spring wheat–fallow (W–F), spring wheat–lentil (Lens culinaris Medic.) (W–L), spring wheat–spring wheat–fallow (W–W–F), and spring wheat–pea (Pisum sativum L.)–fallow (W–P–F)] on transient land previously under 10 years of Conservation Reserve Program (CRP) planting on the amount of plant biomass (stems + leaves) returned to the soil from 1998 to 2003 and soil C and N fractions within the surface 20 cm in March 2004. A continued CRP planting was also included as another treatment for comparing soil C and N fractions. The C and N fractions included soil organic C (SOC), soil total N (STN), microbial biomass C and N (MBC and MBN), potential C and N mineralization (PCM and PNM), and NH₄-N and NO₃-N contents. A field experiment was conducted in a mixture of Scobey clay loam (fine-loamy, mixed, Aridic Argiborolls) and Kevin clay loam (fine, montmorillonitic, Aridic Argiborolls) in Havre, MT, USA. Plant biomass yield varied by crop rotation and year and mean annualized biomass was 45–50% higher in CW and W–F than in W–L. The SOC and PCM were not influenced by treatments. The MBC at 0–5 cm was 26% higher in W–W–F than in W–F. The STN and NO₃-N at 5–20 cm and PNM at 0–5 cm were 17–1206% higher in CT with W–L than in other treatments. Similarly, MBN at 0–5 cm was higher in CT with W–L than in other treatments, except in CT with W–F and W–P–F. Reduction in the length of fallow period increased MBC and MBN but the presence of legumes, such as lentil and pea, in the crop rotation increased soil N fractions. Six years of tillage and crop rotation had minor influence on soil C and N storage between croplands and CRP planting but large differences in active soil C and N fractions.     

Pinostrobin from honey and Thai ginger (Boesenbergia pandurata): a potent flavonoid inducer of mammalian phase 2 chemoprotective and antioxidant enzymes

Over 60 different samples comprising 35 distinct honeys were evaluated for their ability to induce mammalian phase 2 detoxication enzymes using a microtiter plate assay of quinone reductase (QR) induction with murine hepatoma cells in microtiter plates. This assay has been used extensively to identify and isolate a variety of natural and synthetic inducers from plants. All 35 honeys examined induced elevations of mammalian QR activity ranging from 153 to 2155 units/g with a mean of 630 and a median of 417 units/g. The concentrations for doubling the QR activity (CD) of certain of the prominent flavonoids found in honey were also assessed (pinostrobin, 0.5 microM; pinocembrin, 110 microM; chrysin, 25 microM) and compared to those of related, more commonly described flavonoids such as quercetin (2.7 microM) and myricetin (58 microM). On the basis of the extremely high QR inducing potency of one of these compounds, pinostrobin (5-hydroxy-7-methoxyflavanone), a bioassay-guided search was conducted which revealed a dietary source of pinostrobin, Boesenbergia pandurata (fingerroot), with extraordinarily high ability to induce mammalian phase 2 detoxication enzymes. Although the QR inducing activity of buckwheat honeys was 2155 +/- 951 units/g (n = 8 samples), which is less than 10% of the average values obtained from fresh broccoli, the potency of fingerroot rhizomes (ca. 110,000 units/g) is even higher than that of broccoli and the potencies of fingerroot oil and powdered rhizome (ca. 500,000 units/g) rival that of broccoli sprouts.     

Detecting and quantifying the adventitious presence of transgenic seeds in safflower, Carthamus tinctorius L

Safflower ( Carthamus tinctorius L.) is currently being developed as a platform for the production of novel proteins. Methods for detecting and quantifying transgenic safflower are needed to ensure seed quality and to monitor for its adventitious presence. We developed and compared three methods of assaying for transgenic safflower presence in conventional seedlots: field bioassays, enzyme-linked immunosorbent assays (ELISA), and quantitative polymerase chain reaction (Q-PCR). Limits for reliable quantification for both ELISA and Q-PCR are approximately 0.1%, although levels at least as low as 0.02% can be detected by Q-PCR. Levels of quantification for the field bioassay are limited only by space and resources available. Multiple sampling methods to detect and quantify transgenic safflower presence at levels lower than 0.1% were used on field collected samples from a pollen outcrossing experiment to quantify the adventitious presence of transgenic safflower. Taking into account the potential utility and relative advantages or disadvantages of each detection method, it is recommended that the initial testing for the adventitious presence of transgenic seed be carried out using an antibody-based test if available and that Q-PCR-based assays to quantify transgenic proportion be used when it is necessary to identify specific transgenic constructs or if antibody-based assays are not readily available.     

Cytology and the cell block method in diagnostic characterization of canine lymphadenopathy and in the immunophenotyping of nodal lymphoma

Minimally invasive techniques used to evaluate canine peripheral lymphadenopathy (PLN), including fine needle aspiration biopsy with cytological evaluation (FNAB‐C) and flow cytometry (FC), have benefits and limitations. The cell block (CB) method is an alternate processing technique in which fine needle aspirate biopsy samples are concentrated, fixed, and embedded in paraffin for routine histological processing/staining. Utilizing three observers, we determined the diagnostic value of the CB in evaluating canine PLN across six categories (non‐diagnostic, reactive, inflammatory/infectious, probable lymphoma and lymphoma, metastatic neoplasia) and correlated findings to immunophenotypic and clonal antigen receptor rearrangement results in canine nodal lymphoma. Eighty‐five paired FNAB‐C and CB samples were evaluated from canine patients presenting to the University of Minnesota Veterinary Oncology or Internal Medicine services. Diagnostic quality samples were obtained in 55/85 (65%) CB and 81/85 (95%) FNAB‐C samples, respectively, and nodal pathology impacted CB diagnostic yield. Overall percent agreement between diagnostic‐quality FNAB‐C and CB samples was 86%, but increased to 95% if the categories of lymphoma and probable lymphoma were combined. There was 100% agreement for both the diagnoses of metastatic neoplasia and reactive lymph nodes and 92% agreement for the diagnosis of lymphoma/probable lymphoma. Using immunohistochemistry (IHC), CB samples correctly immunophenotyped 22/23 (96%) cases of B‐cell lymphoma, but only 1/6 (17%) cases of T‐cell lymphoma. IHC was not completed on nine cases of lymphoproliferative disease because of insufficient cellularity. When the CB method (CBM) yielded diagnostic quality samples there was good to excellent agreement with FNAB‐C samples and CB samples were suitable for some IHC tests.     

Regulation of water loss in populations of Populus trichocarpa: the role of stomatal control in preventing xylem cavitation

Variations in resistance to drought-induced xylem cavitation, xylem air-entry points, stomatal behavior, and hydraulic conductivity were measured in four populations of Populus trichocarpa Torr. & A. Gray collected along an east-west humidity and temperature gradient in Washington State, USA. Xylem air-entry points were less negative in trees from moist environments (-0.71 and -1.32 MPa in the Hoh and Nisqually populations, respectively) than in trees from dry environments (-1.55 and -1.67 MPa in the Palouse and Yakima populations, respectively). Xylem cavitation in response to experimental drought was consistent with air-injection measures of xylem air-entry points for a given population. Populations vulnerable to cavitation also exhibited higher stem specific hydraulic conductivities and limited stomatal control compared with resistant populations. Populations exhibiting vulnerability to cavitation and limited stomatal control desiccated more rapidly during drought compared with resistant populations. This study provides evidence of interpopulation variation in resistance to drought-induced xylem cavitation, stomatal behavior, and hydraulic conductivity within Populus trichocarpa.     

Increases in heat-induced tree mortality could drive reductions of biomass resources in Canada’s managed boreal forest

Landscape Ecology - The Canadian boreal forest provides valuable ecosystem services that are regionally and globally significant. Despite its importance, the future of the Canadian boreal forest is...