Permeability of commercial landscapes: integrating plantation forest trackways into ecological networks

Context: Reconnecting fragmented habitat is a major challenge in biodiversity conservation. It is especially important in landscapes that have undergone significant change through agriculture and forestry conversion. This is particularly prevalent within heathland regions across Western Europe where remaining fragments are significantly isolated in intensely managed landscapes. Objectives: This study examines to what extent forest trackways can facilitate connectivity between open patches, and how invertebrate dispersal ability (terrestrial or aerial) influences functional landscape connectivity. We also investigate a range of management scenarios to examine the efficacy of landscape management plans to facilitate connectivity for vulnerable invertebrate communities. Methods: We develop the Path-Cost Index (PCI) that combines multiple environmental factors to quantify species-specific habitat suitability within forestry trackways. The PCI generates dispersal cost values for resistance-based connectivity models that represent specific forest environments and species/guild responses. We demonstrate the use of this index through the modelling of least-cost pathways for heathland invertebrates and test management scenarios (clustered and contiguous habitat improvements) developed to support heathland biodiversity. Results: The plantation landscape provided significant barriers for vulnerable heathland invertebrate guilds. Landscape metrics indicate that management plans incorporating contiguous corridors would provide significantly greater improvements over clustered corridors for target invertebrate guilds in our study landscape. Conclusion: The PCI presented in this study delivered easily definable resistance costs allowing comparative assessment of landscape enhancements plans. The PCI can be easily adapted to other linear features and landscapes, affording a low-cost tool to assist the evaluation of management plans and biological networks

The value of the trackway system within a lowland plantation forest for ground-active spiders

European forest management guidelines include conservation and enhancement of biodiversity. Within plantation forestry, trackways provide contiguous permanent open-habitat with potential to enhance biodiversity. We examined the ground-active spider assemblage in the trackway network of Thetford Forest, Eastern England, the largest lowland conifer forest in the UK, created by afforestation of heathland and farmland. Results are relevant to other forests in heath regions across Europe. We used pitfall trapping to sample the spider assemblage of trackways within thicket-aged stands (n = 17), mature stands (n = 13) and heathland reference sites (n = 9). A total of 9,314 individuals of 71 species were recorded. Spider assemblages of the trackway network were distinct from those of the heathland reference sites; however, trackways were found to support specialist species associated with grass-heath habitats, including nationally scarce species. Richness of grass-heath species was similar for trackways in thicket-aged forest and heathland reference sites, although the abundance of individuals was three times greater in the reference sites. Trackways in mature stands had lower grass-heath species richness and abundance than both thicket trackways and heath reference sites. Wide trackways within thicket stands contained greater richness and abundance of specialist xeric species than narrower trackways. However, fewer xeric individuals were found in trackways compared to heathland reference sites. Either inferior habitat quality in trackways or poor dispersal ability of specialist xeric species may largely restrict these to relict areas of heathland. Targeted widening of trackways to allow permanent unshaded habitat and creating early successional stages by mechanical disturbance regimes could improve trackway suitability for specialist species, helping to restore connectivity networks for grass-heath biodiversity

Physical disturbance enhances ecological networks for heathland biota: A multiple taxa experiment

Creation of ecological networks is advocated to increase the viability of regional populations and their resilience to climatic and land-use change with associated habitat fragmentation and loss. However, management of network elements should be appropriate for the regional biota conserved, requiring evidence from multiple taxa. We examined the response of carabids, spiders, ants and vascular plants, to six physical disturbance treatments ranging in intensity plus controls, replicated across 63 plots in a plantation trackway network of a heathland region in England. Over two years, 73 182 invertebrates from 256 species were identified and 23 241 observations of 222 vascular plant species made. Abundance and richness of stenotopic carabids and plants (respectively associated with heath and dune, or unshaded physically-disturbed low-nutrient soils) increased with disturbance intensification. Ant assemblages were similar among treatments and control plots, only differing from heathland sites through addition of generalist species. Spider assemblages were less resilient; overall abundance and richness reduced with greater disturbance. Generalist spiders recovered in year two, although incompletely in the most intensely disturbed treatment. Contrasting responses among taxonomic groups likely reflect differences in dispersal ability. Treatments that merely disrupted vegetation quickly regained plant cover and height, suggesting frequent reapplication will be required to maintain heath specialist species. Turf stripping, the most severe treatment, was quickly colonised by specialist carabid and plant species. Treatments that are more durable may allow stenotopic spider assemblages to develop in contrast to shorter-lived treatments. Effectiveness of early-successional habitat networks within regions supporting European lowland heathland will be enhanced by physical disturbance and turf stripping. Our results emphasise the importance of examining multiple taxonomic groups when assessing management outcomes

Can ground-based assessments of forest biodiversity reflect the biological condition of canopy assemblages?

© 2015 . Biological assessments of forest systems often involve a single ground-invertebrate sampling method that may ignore the biological component of the non-sampled canopy. Pitfall trapping for ground-active arthropods is a widely implemented technique for biological assessment in forested and open habitats. Although much evidence highlights the biases of pitfall trapping, this evidence typically comes from open-habitat crop and grassland systems. In forest systems where much of the biodiversity is found within the above-ground structure, management recommendations based solely on ground sampling may not represent the diversity within the three dimensional forest habitat. We provide evidence from combined ground and canopy sampling of three major forest types within the study region. We use canopy insecticide fogging to compare with more traditional ground-based pitfall trapping, and use spiders as a comparative species-rich biota that is able to colonise most terrestrial habitats and is strongly affected by changes in environmental condition.We identified 3933 spiders from 109 species from the 18 forest patches sampled. Both types of sampling defined differences in community composition between forest types in a similar manner; hence, either method could be used to evaluate differences or test management regimes in well-replicated experiments of forest type. However, the association in community composition between ground and canopy assemblages at the individual site-based level was weak; we found low correlation between the two data sets indicating that surrogacy between methods was not supported at this level. Furthermore, disparities in spider habitat association, body size, hunting guild and vertical stratification of spider families indicates that where detailed species and family-based information is required, or if inventorying is necessary, then multiple targeted surveys are essential

Functional shifts in bird communities from semi-natural oak forests to conifer plantations are not consistent across Europe

While the area of plantation forest increased globally between 2010 and 2015, more than twice the area of natural forests was lost over the same period (6.5 million ha natural forest lost per year versus 3.2 million ha plantation gained per year). Consequently, there is an increasing need to understand how plantation land use affects biodiversity. The relative conservation value of plantation forests is context dependent, being influenced by previous land use, management regimes and landscape composition. What is less well understood, and of importance to conservation management, is the consistency of diversity patterns across regions, and the degree to which useful generalisations can be provided within and among bioregions. Here, we analyse forest birds in Ireland, France and Portugal, representing distinct regions across the Atlantic biogeographic area of Europe. We compared taxonomic, functional and phylogenetic diversity of bird communities among conifer plantations and semi-natural oak forests, and assessed correlations between species traits and forest type across these regions. Although bird composition (assessed with NMDS ordination) differed consistently between plantation and oak forests across all three regions, species richness and Shannon diversity did not show a consistent pattern. In Ireland and France, metrics of taxonomic diversity (richness and Shannon diversity), functional diversity, functional dispersion and phylogenetic diversity were greater in oak forests than plantations. However, in Portugal taxonomic and phylogenetic diversity did not differ significantly between forest types, while functional diversity and dispersion were statistically significantly greater in plantations. No single bird trait-forest type association correlated in a consistent direction across the three study regions. Trait associations for the French bird communities appeared intermediate between those in Ireland and Portugal, and when trait correlations were significant in both Ireland and Portugal, the direction of the correlation was always opposite. The variation in response of bird communities to conifer plantations indicates that care is needed when generalising patterns of community diversity and assembly mechanisms across regions

A G-quadruplex-binding compound showing anti-tumour activity in an in vivo model for pancreatic cancer

We report here that a tetra-substituted naphthalene-diimide derivative (MM41) has significant in vivo anti-tumour activity against the MIA PaCa-2 pancreatic cancer xenograft model. IV administration with a twice-weekly 15 mg/kg dose produces ca 80% tumour growth decrease in a group of tumour-bearing animals. Two animals survived tumour-free after 279 days. High levels of MM41 are rapidly transported into cell nuclei and were found to accumulate in the tumour. MM41 is a quadruplex-interactive compound which binds strongly to the quadruplexes encoded in the promoter sequences of the BCL-2 and k-RAS genes, both of which are dis-regulated in many human pancreatic cancers. Levels of BCL-2 were reduced by ca 40% in tumours from MM41-treated animals relative to controls, consistent with BCL-2 being a target for MM41. Molecular modelling suggests that MM41 binds to a BCL-2 quadruplex in a manner resembling that previously observed in co-crystal structures with human telomeric quadruplexes. This supports the concept that MM41 (and by implication other quadruplex-targeting small molecules) can bind to quadruplex-forming promoter regions in a number of genes and down-regulate their transcription. We suggest that quadruplexes within those master genes that are up-regulated drivers for particular cancers, may be selective targets for compounds such as MM41

Targeting multiple effector pathways in pancreatic ductal adenocarcinoma with a g-quadruplex-binding small molecule

Human pancreatic ductal adenocarcinoma (PDAC) involves the dysregulation of multiple signaling pathways. A novel approach to the treatment of PDAC is described, involving the targeting of cancer genes in PDAC pathways having over-representation of G-quadruplexes, using the trisubstituted naphthalene diimide quadruplex-binding compound 2,7-bis(3-morpholinopropyl)-4-((2-(pyrrolidin-1-yl)ethyl)amino)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (CM03). This compound has been designed by computer modeling, is a potent inhibitor of cell growth in PDAC cell lines, and has anticancer activity in PDAC models, with a superior profile compared to gemcitabine, a commonly used therapy. Whole-transcriptome RNA-seq methodology has been used to analyze the effects of this quadruplex-binding small molecule on global gene expression. This has revealed the down-regulation of a large number of genes, rich in putative quadruplex elements and involved in essential pathways of PDAC survival, metastasis, and drug resistance. The changes produced by CM03 represent a global response to the complexity of human PDAC and may be applicable to other currently hard-to-treat cancers

Rotavirus Rearranged Genomic RNA Segments Are Preferentially Packaged into Viruses Despite Not Conferring Selective Growth Advantage to Viruses

The rotavirus (RV) genome consists of 11 double-stranded RNA segments. Sometimes, partial sequence duplication of an RNA segment leads to a rearranged RNA segment. To specify the impact of rearrangement, the replication efficiencies of human RV with rearranged segments 7, 11 or both were compared to these of the homologous human wild-type RV (wt-RV) and of the bovine wt-RV strain RF. As judged by viral growth curves, rotaviruses with a rearranged genome (r-RV) had no selective growth advantage over the homologous wt-RV. In contrast, r-RV were selected over wt-RV during competitive experiments (i.e mixed infections between r-RV and wt-RV followed by serial passages in cell culture). Moreover, when competitive experiments were performed between a human r-RV and the bovine wt-RV strain RF, which had a clear growth advantage, rearranged segments 7, 11 or both always segregated in viral progenies even when performing mixed infections at an MOI ratio of 1 r-RV to 100 wt-RV. Lastly, bovine reassortant viruses that had inherited a rearranged segment 7 from human r-RV were generated. Although substitution of wt by rearranged segment 7 did not result in any growth advantage, the rearranged segment was selected in the viral progenies resulting from mixed infections by bovine reassortant r-RV and wt-RV, even for an MOI ratio of 1 r-RV to 107 wt-RV. Lack of selective growth advantage of r-RV over wt-RV in cell culture suggests a mechanism of preferential packaging of the rearranged segments over their standard counterparts in the viral progeny

Mathematical model describing erythrocyte sedimentation rate. Implications for blood viscosity changes in traumatic shock and crush syndrome

BACKGROUND: The erythrocyte sedimentation rate (ESR) is a simple and inexpensive laboratory test, which is widespread in clinical practice, for assessing the inflammatory or acute response. This work addresses the theoretical and experimental investigation of sedimentation a single and multiple particles in homogeneous and heterogeneous (multiphase) medium, as it relates to their internal structure (aggregation of solid or deformed particles). METHODS: The equation system has been solved numerically. To choose finite analogs of derivatives we used the schemes of directional differences. RESULTS: (1) Our model takes into account the influence of the vessel wall on group aggregation of particles in tubes as well as the effects of rotation of particles, the constraint coefficient, and viscosity of a mixture as a function of the volume fraction. (2) This model can describe ESR as a function of the velocity of adhesion of erythrocytes; (3) Determination of the ESR is best conducted at certain time intervals, i.e. in a series of periods not exceeding 5 minutes each; (4) Differential diagnosis of various diseases by means of ESR should be performed using the aforementioned timed measurement of ESR; (5) An increase in blood viscosity during trauma results from an increase in rouleaux formation and the time-course method of ESR will be useful in patients with trauma, in particular, with traumatic shock and crush syndrome. CONCLUSION: The mathematical model created in this study used the most fundamental differential equations that have ever been derived to estimate ESR. It may further our understanding of its complex mechanism