Evaluation of buffer-radius modelling approaches used in forest conservation and planning

Spatial modelling approaches are increasingly being used to direct forest management and conservation planning at the landscape scale. A popular approach is the use of buffer-radius methods, which create buffers around distinct forest habitat patches to assess habitat connectivity within anthropogenic landscapes. However, the effectiveness and sensitivity of such methods have rarely been evaluated. In this study, Euclidean and least-cost buffer-radius approaches were used to predict functional ecological networks within the wooded landscape of the Isle of Wight (UK). To parameterize the models, a combination of empirical evidence and expert knowledge was used relating to the dispersal ability of a model species, the wood cricket (Nemobius sylvestris Bosc.). Three scenarios were developed to assess the influence of increasing the amount of spatial and species-specific input data on the model outcomes. This revealed that the level of habitat fragmentation for the model species is likely to be underestimated when few empirical data are available. Furthermore, the least-cost buffer approach outperformed simple Euclidean buffer in predicting presence and absence for the model species. Sensitivity analyses on model performance revealed high sensitivity of the models to variation in buffer distance (i.e. maximum dispersal distance) and permeability of common landscape features such as roads, watercourses, grassland and semi-natural habitat. This indicates that when data are lacking with which to parameterize buffer-radius models, the model outcomes need to be interpreted with caution. This study also showed that if sufficient empirical data are available, least-cost buffer approaches have the potential to be a valuable tool to assist forest managers in making informed decisions. However, least-cost approaches should always be used as an indicative rather than prescriptive management tool to support forest landscape conservation and planning

The opposing effects of isotropic and anisotropic attraction on association kinetics of proteins and colloids

The association and dissociation of particles via specific anisotropic interactions is a fundamental process, both in biology (proteins) and in soft matter (colloidal patchy particles). The presence of alternative binding sites can lead to multiple productive states and also to non-productive “decoy” or intermediate states. Besides anisotropic interactions, particles can experience non-specific isotropic interactions. We employ single replica transition interface sampling to investigate how adding a non-productive binding site or a nonspecific isotropic interaction alters the dimerization kinetics of a generic patchy particle model. The addition of a decoy binding site reduces the association rate constant, independent of the site’s position, while adding an isotropic interaction increases it due to an increased rebinding probability. Surprisingly, the association kinetics becomes non-monotonic for a tetramer complex formed by multivalent patchy particles. While seemingly identical to twoparticle binding with a decoy state, the cooperativity of binding multiple particles leads to a kinetic optimum. Our results are relevant for the understanding and modeling of biochemical networks and self-assembly processes. Published by AIP Publishing. https://doi.org/10.1063/1.500648

Low migratory connectivity is common in long-distance migrant birds

TF benefitted from a Natural Environment Research Council studentship (student number 6109659) and AF from a Natural Environment research grant NE/K006321/1.1. Estimating how much long-distance migrant populations spread out and mix during the non-breeding season (migratory connectivity) is essential for understanding and predicting population dynamics in the face of global change. 2. We quantify variation in population spread and inter-population mixing in long- distance, terrestrial migrant land-bird populations (712 individuals from 98 populations of 45 species, from tagging studies in the Neotropic and Afro-Palearctic flyways). We evaluate the Mantel test as a metric of migratory connectivity, and explore the extent to which variance in population spread can be explained simply by geography. 3. The mean distance between two individuals from the same population during the non- breeding season was 743 km, covering 10–20% of the maximum width of Africa / South America. Individuals from different breeding populations tended to mix during the non-breeding season, though spatial segregation was maintained in species with relatively large non-breeding ranges (and, to a lesser extent, those with low population-level spread). A substantial amount of between-population variation in population spread was predicted simply by geography, with populations using non- breeding zones with limited land availability (e.g. Central America compared to South America) showing lower population spread. 4. The high levels of population spread suggest that deterministic migration strategies are not generally adaptive; this makes sense in the context of the recent evolution of the systems, and the spatial and temporal unpredictability of non-breeding habitat. 5. The conservation implications of generally low connectivity are that the loss (or protection) of any non-breeding site will have a diffuse but widespread effect on many breeding populations. Although low connectivity should engender population resilience to shifts in habitat (e.g. due to climate change), we suggest it may increase susceptibility to habitat loss. We hypothesise that because a migrant species cannot adapt to both simultaneously, migrants generally may be more susceptible to population declines in the face of concurrent anthropogenic habitat and climate change.Publisher PDFPeer reviewe

Forest landscape restoration in the drylands of Latin America

Forest Landscape Restoration (FLR) involves the ecological restoration of degraded forest landscapes, with the aim of benefiting both biodiversity and human well-being. We first identify four fundamental principles of FLR, based on previous definitions. We then critically evaluate the application of these principles in practice, based on the experience gained during an international, collaborative research project conducted in six dry forest landscapes of Latin America. Research highlighted the potential for FLR; tree species of high socioeconomic value were identified in all study areas, and strong dependence of local communities on forest resources was widely encountered, particularly for fuelwood. We demonstrated that FLR can be achieved through both passive and active restoration approaches, and can be cost-effective if the increased provision of ecosystem services is taken into account. These results therefore highlight the potential for FLR, and the positive contribution that it could make to sustainable development. However, we also encountered a number of challenges to FLR implementation, including the difficulty of achieving strong engagement in FLR activities among local stakeholders, lack of capacity for community-led initiatives, and the lack of an appropriate institutional and regulatory environment to support restoration activities. Successful implementation of FLR will require new collaborative alliances among stakeholders, empowerment and capacity building of local communities to enable them to fully engage with restoration activities, and an enabling public policy context to enable local people to be active participants in the decision making process. © 2012 by the author(s). Published here under license by the Resilience Alliance

Mid-Miocene cooling and the extinction of tundra in continental Antarctica

A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40Ar/39Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ± 0.05 Ma and 13.85 ± 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition

Species distribution modeling in the tropics: problems, potentialities, and the role of biological data for effective species conservation

In this paper we aim to investigate the problems and potentialities of species distribution modeling (SDM) as a tool for conservation planning and policy development and implementation in tropical regions. We reviewed 123 studies published between 1995 and 2007 in five of the leading journals in ecology and conservation, and examined two tropical case studies in which distribution modeling is currently being applied to support conservation planning. We also analyzed the characteristics of data typically used for fitting models within the specific context of modeling tree species distribution in Central America. The results showed that methodological papers outnumbered reports of SDMs being used in an applied context for setting conservation priorities, particularly in the tropics. Most applications of SDMs were in temperate regions and biased towards certain organisms such as mammals and birds. Studies from tropical regions were less likely to be validated than those from temperate regions. Unpublished data from two major tropical case studies showed that those species that are most in need of conservation actions, namely those that are the rarest or most threatened, are those for which SDM is least likely to be useful. We found that only 15% of the tree species of conservation concern in Central America could be reliably modelled using data from a substantial source (Missouri Botanical Garden VAST database). Lack of data limits model validation in tropical areas, further restricting the value of SDMs. We concluded that SDMs have a great potential to support biodiversity conservation in the tropics, by supporting the development of conservation strategies and plans, identifying knowledge gaps, and providing a tool to examine the potential impacts of environmental change. However, for this potential to be fully realized, problems of data quality and availability need to be overcome. Weaknesses in current biological datasets need to be systematically addressed, by increasing collection of field survey data, improving data sharing and increasing structural integration of data sources. This should include use of distributed databases with common standards, referential integrity, and rigorous quality control. Integration of data management with SDMs could significantly add value to existing data resources by improving data quality control and enabling knowledge gaps to be identified

AKAP-Lbc mobilizes a cardiac hypertrophy signaling pathway.

Elevated catecholamines in the heart evoke transcriptional activation of the Myocyte Enhancer Factor (MEF) pathway to induce a cellular response known as pathological myocardial hypertrophy. We have discovered that the A-Kinase Anchoring Protein (AKAP)-Lbc is upregulated in hypertrophic cardiomyocytes. It coordinates activation and movement of signaling proteins that initiate MEF2-mediated transcriptional reprogramming events. Live-cell imaging, fluorescent kinase activity reporters, and RNA interference techniques show that AKAP-Lbc couples activation of protein kinase D (PKD) with the phosphorylation-dependent nuclear export of the class II histone deacetylase HDAC5. These studies uncover a role for AKAP-Lbc in which increased expression of the anchoring protein selectively amplifies a signaling pathway that drives cardiac myocytes toward a pathophysiological outcome