Anthropogenic landscape change promotes asymmetric dispersal and limits regional patch occupancy in a spatially structured bird population

1. Local extinctions in habitat patches and asymmetric dispersal between patches are key processes structuring animal populations in heterogeneous environments. Effective landscape conservation requires an understanding of how habitat loss and fragmentation influence demographic processes within populations and movement between populations. 2. We used patch occupancy surveys and molecular data for a rainforest bird, the logrunner (Orthonyx temminckii), to determine (i) the effects of landscape change and patch structure on local extinction; (ii) the asymmetry of emigration and immigration rates; (iii) the relative influence of local and between-population landscapes on asymmetric emigration and immigration; and (iv) the relative contributions of habitat loss and habitat fragmentation to asymmetric emigration and immigration. 3. Whether or not a patch was occupied by logrunners was primarily determined by the isolation of that patch. After controlling for patch isolation, patch occupancy declined in landscapes experiencing high levels of rainforest loss over the last 100 years. Habitat loss and fragmentation over the last century was more important than the current pattern of patch isolation alone, which suggested that immigration from neighbouring patches was unable to prevent local extinction in highly modified landscapes. 4. We discovered that dispersal between logrunner populations is highly asymmetric. Emigration rates were 39% lower when local landscapes were fragmented, but emigration was not limited by the structure of the between-population landscapes. In contrast, immigration was 37% greater when local landscapes were fragmented and was lower when the between-population landscapes were fragmented. Rainforest fragmentation influenced asymmetric dispersal to a greater extent than did rainforest loss, and a 60% reduction in mean patch area was capable of switching a population from being a net exporter to a net importer of dispersing logrunners. 5. The synergistic effects of landscape change on species occurrence and asymmetric dispersal have important implications for conservation. Conservation measures that maintain large patch sizes in the landscape may promote asymmetric dispersal from intact to fragmented landscapes and allow rainforest bird populations to persist in fragmented and degraded landscapes. These sink populations could form the kernel of source populations given sufficient habitat restoration. However, the success of this rescue effect will depend on the quality of the between-population landscapes.     

Advancing marine conservation planning in the Mediterranean Sea

Twenty leading scientists in the field of marine conservation planning attended the first international workshop on conservation planning in the Mediterranean Sea. This globally significant biodiversity hotspot has been subjected to human exploitation and degradation for 1,000s of years. Recently, several initiatives have tried to identify priority areas for conservation across the Mediterranean Sea. However, none of these efforts have led to large-scale actions yet. The aim of the workshop was to establish a network of scientists who are involved in large-scale conservation planning initiatives throughout the Mediterranean basin to promote collaboration and reduce redundancy in conservation initiatives. The three focus groups of the workshop build on existing efforts and intend to deliver: (1) a roadmap for setting conservation priorities, (2) a methodological framework for linking threats, actions and costs to improve the prioritization process, and (3) a systematic conservation planning process tailored to complex environments such as the Mediterranean Sea. Joining forces and involving more scientists (especially from the South-eastern part of the region) in following meetings, the participants endeavour to provide guidelines on how to bridge the science-policy gap and hence aid decision-makers to take efficient conservation actions.     

Cost-benefit analysis for intentional plant introductions under uncertainty

Worldwide, we rely on introduced plants for the essentials of human life; however, intentional plant introductions for commercial benefit have resulted in invaders with negative environmental, economic or social impacts. We argue that plant species of low expected economic value should be less acceptable for introduction than species of high economic value if their other traits are similar; however, key traits such as likelihood of escape and costs of escape are often highly uncertain. Methods do not currently exist which allow decision makers to evaluate costs and benefits of introduction under uncertainty. We developed a cost-benefit analysis for determining plant introduction that incorporates probability of escape, expected economic costs after escape, expected commercial benefits, and the efficiency and cost of containment. We used a model to obtain optimal decisions for the introduction and containment of commercial plants while maximizing net benefit or avoiding losses. We also obtained conditions for robust decisions which take into account severe uncertainty in model parameters using information-gap decision theory. Optimal decisions for introduction and containment of commercial plants depended, not only on the probability of escape and subsequent costs incurred, but also on the anticipated commercial benefit, and the cost and efficiency of containment. When our objective is to maximize net benefit, increasing uncertainty in parameter values increased the likelihood of introduction; in contrast, if our objective is to avoid losses, more uncertainty decreased the likelihood of introduction.     

Conservation planning with irreplaceability: does the method matter?

A number of systematic conservation planning tools are available to aid in making land use decisions. Given the increasing worldwide use and application of reserve design tools, including measures of site irreplaceability, it is essential that methodological differences and their potential effect on conservation planning outcomes are understood. We compared the irreplaceability of sites for protecting ecosystems within the Brigalow Belt Bioregion, Queensland, Australia, using two alternative reserve system design tools, Marxan and C-Plan. We set Marxan to generate multiple reserve systems that met targets with minimal area; the first scenario ignored spatial objectives, while the second selected compact groups of areas. Marxan calculates the irreplaceability of each site as the proportion of solutions in which it occurs for each of these set scenarios. In contrast, C-Plan uses a statistical estimate of irreplaceability as the likelihood that each site is needed in all combinations of sites that satisfy the targets. We found that sites containing rare ecosystems are almost always irreplaceable regardless of the method. Importantly, Marxan and C-Plan gave similar outcomes when spatial objectives were ignored. Marxan with a compactness objective defined twice as much area as irreplaceable, including many sites with relatively common ecosystems. However, targets for all ecosystems were met using a similar amount of area in C-Plan and Marxan, even with compactness. The importance of differences in the outcomes of using the two methods will depend on the question being addressed; in general, the use of two or more complementary tools is beneficial.     

The hydrogenosomes of Psalteriomonas lanterna

Background  

Hydrogenosomes are organelles that produce molecular hydrogen and ATP. The broad phylogenetic distribution of their hosts suggests that the hydrogenosomes of these organisms evolved several times independently from the mitochondria of aerobic progenitors. Morphology and 18S rRNA phylogeny suggest that the microaerophilic amoeboflagellate Psalteriomonas lanterna, which possesses hydrogenosomes and elusive "modified mitochondria", belongs to the Heterolobosea, a taxon that consists predominantly of aerobic, mitochondriate organisms. This taxon is rather unrelated to taxa with hitherto studied hydrogenosomes.     

Graph theoretic topology of the Great but small Barrier Reef world

The transport of larvae between coral reefs is critical to the functioning of Australia’s Great Barrier Reef (GBR) because it determines recruitment rates and genetic exchange. One way of modelling the transport of larvae from one reef to another is to use information about currents. However the connectivity relationships of the entire system have not been fully examined. Graph theory provides a framework for the representation and analysis of connections via larval transport. In the past, the geometric arrangement (topology) of biological systems, such as food webs and neural networks, has revealed a common set of characteristics known as the ‘small world’ property. We use graph theory to examine and describe the topology and connectivity of a species living in 321 reefs in the central section of the GBR over 32 years. This section of the GBR can be described by a directional weighted graph, and we discovered that it exhibits scale-free small-world characteristics. The conclusion that the GBR is a small-world network for biological organisms is robust to variation in both the life history of the species modelled and yearly variation in hydrodynamics. The GBR is the first reported mesoscale biological small-world network.     

A climatic stability approach to prioritizing global conservation investments

Climate change is impacting species and ecosystems globally. Many existing templates to identify the most important areas to conserve terrestrial biodiversity at the global scale neglect the future impacts of climate change. Unstable climatic conditions are predicted to undermine conservation investments in the future. This paper presents an approach to developing a resource allocation algorithm for conservation investment that incorporates the ecological stability of ecoregions under climate change. We discover that allocating funds in this way changes the optimal schedule of global investments both spatially and temporally. This allocation reduces the biodiversity loss of terrestrial endemic species from protected areas due to climate change by 22% for the period of 2002-2052, when compared to allocations that do not consider climate change. To maximize the resilience of global biodiversity to climate change we recommend that funding be increased in ecoregions located in the tropics and/or mid-elevation habitats, where climatic conditions are predicted to remain relatively stable. Accounting for the ecological stability of ecoregions provides a realistic approach to incorporating climate change into global conservation planning, with potential to save more species from extinction in the long term.     

Plastid-DNA levels in the different tissues of potato

The plastid-(pt) DNA levels in the different tissues of potato (Solanum tuberosum L.), including tubers of differing ages, have been studied. The DNA could be detected as a single nucleoid in amyloplasts of cells from young potato tubers by fluorescence microscopy, following staining of glutaraldehyde-fixed tissue with 4,6-diamidino-2-phenyl indole (DAPI). The renaturation kinetics of spinach ptDNA in the presence of total DNA from potato tissues and the fragments generated by restriction-enzyme digestion of potato-tuber DNA and chloroplast DNA indicated that the ptDNA of potato-tuber amyloplasts and of potato-leaf chloroplasts is essentially the same. Expressed as a percentage of the total DNA the level of ptDNA (5.2%) found in tubers, while less than that found in leaves (7.6%) was more than that found in petioles (3.4%), stems (3.0%) and roots (1.0%). There was a high level of both nuclear and plastid ploidy in mature potato-tuber cells and, on average, nuclei contained 32 pg of DNA (equivalent to 14C) and the 40 amyloplasts per cell contained DNA equivalent to 7800 copies of ptDNA, or 195 copies per amyloplast.Abbreviations DAPI 4,6-diamidino-2-phenyl-indole - LSU large sub-unit of ribulose-1,5-bisphosphate carboxylase - mtDNA mitochondrial DNA - ptDNA chloroplast or plastid DNA     

Nuclear DNA regulates the level of ribulose 1,5-bisphosphate carboxylase oxygenase in Medicago sativa L.

Summary The response to selection for leaf proteins was studied during three selection cycles. Selection for high total nitrogen content showed 75% heritability, and the levels of both ribulose 1,5-bisphosphate carboxylase oxygenase (Rubisco) and cytoplasmic protein were strongly under nuclear DNA control. High and low protein content were correlated with chloroplast area. Although the amounts of nuclear DNA were similar, the ratio of Rubisco/DNA and chlorophyll/DNA changed during the selection process. It can be concluded that the levels of Rubisco achieved in mature plants of M. sativa are under nuclear DNA control. The possible involvement of small subunit (SSU) genes in controlling these levels is discussed.