Assessing multi-taxa sensitivity to the human footprint,habitat fragmentation and loss by exploring alternative scenarios of dispersal ability and population size: a simulation approach

Quantifying the effects of landscape change on population connectivity is compounded by uncertainties about population size and distribution and a limited understanding of dispersal ability for most species. In addition, the effects of anthropogenic landscape change and sensitivity to regional climatic conditions interact to strongly affect habitat fragmentation and loss. To further develop conservation theory and to understand the interplay between all of these factors, we simulated habitat fragmentation and loss across the Western United States for several hypothetical species associated with four biome types, and a range of habitat requirements and dispersal abilities. We found dispersal ability and population size of the focal species to be equally sensitive to habitat extent, while dispersal ability is more sensitive to habitat fragmentation. There were also strong critical threshold effects where habitat connectivity decreased disproportionately to decreases in life-history traits making these species near these thresholds more sensitive to changes in habitat loss and fragmentation. Overall, grassland and forest associated species are also most at risk from habitat loss and fragmentation driven by human related land-use. These two largest biome types were most sensitive at large contiguous patch sizes which is often considered most important for metapopulation viability and biodiversity conservation. Hypothetical simulation studies such as this can be of great value to scientists in further conceptualizing and developing conservation theory, and evaluating spatially-explicit scenarios of habitat connectivity. Our results are available for download in a web-based interactive mapping prototype useful for accessing the results of this study.     

Developing a vision for improved monitoring and reporting of riparian restoration projects

Representatives from agencies involved in natural resource management in the Murray‐Darling Basin gathered for a workshop in November 2010 to develop a vision for improved monitoring and reporting of riparian restoration projects. The resounding message from this workshop was that the effectiveness of riparian restoration depends on having sound, documented and agreed evidence on the ecological responses to restoration efforts. Improving our capacity to manage and restore riparian ecosystems is constrained by (i) a lack of ecological evidence on the effects of restoration efforts, and (ii) short‐termism in commitment to restoration efforts, in funding of monitoring and in expected time spans for ecosystem recovery. Restoration at the effective spatial scope will invariably require a long‐term commitment by researchers, funding agencies, management agencies and landholders. To address the knowledge gaps that constrain riparian restoration in the Basin, participants endorsed four major fields for future research: the importance of landscape context to restoration outcomes; spatio‐temporal scaling of restoration outcomes; functional effects of restoration efforts; and developing informative and effective indicators of restoration. To improve the monitoring and restoration of riparian zones throughout the Basin, participants advocated an integrated approach: a hierarchical adaptive management framework that incorporates long‐term ecological research.     

Coral population dynamics across consecutive mass mortality events

Annual coral mortality events due to increased atmospheric heat may occur regularly from the middle of the century and are considered apocalyptic for coral reefs. In the Arabian/Persian Gulf, this situation has already occurred and population dynamics of four widespread corals (Acropora downingi, Porites harrisoni, Dipsastrea pallida, Cyphastrea micropthalma) were examined across the first‐ever occurrence of four back‐to‐back mass mortality events (2009–2012). Mortality was driven by diseases in 2009, bleaching and subsequent diseases in 2010/2011/2012. 2009 reduced P. harrisoni cover and size, the other events increasingly reduced overall cover (2009: ?10%; 2010: ?20%; 2011: ?20%; 2012: ?15%) and affected all examined species. Regeneration was only observed after the first disturbance. P. harrisoni and A. downingi severely declined from 2010 due to bleaching and subsequent white syndromes, while D. pallida and P. daedalea declined from 2011 due to bleaching and black‐band disease. C. microphthalma cover was not affected. In all species, most large corals were lost while fission due to partial tissue mortality bolstered small size classes. This general shrinkage led to a decrease of coral cover and a dramatic reduction of fecundity. Transition matrices for disturbed and undisturbed conditions were evaluated as Life Table Response Experiment and showed that C. microphthalma changed the least in size‐class dynamics and fecundity, suggesting they were ‘winners’. In an ordered ‘degradation cascade’, impacts decreased from the most common to the least common species, leading to step‐wise removal of previously dominant species. A potentially permanent shift from high‐ to low‐coral cover with different coral community and size structure can be expected due to the demographic dynamics resultant from the disturbances. Similarities to degradation of other Caribbean and Pacific reefs are discussed. As comparable environmental conditions and mortality patterns must be expected worldwide, demographic collapse of many other coral populations may soon be widespread.     

Animal movements in fire‐prone landscapes

Movement is a trait of fundamental importance in ecosystems subject to frequent disturbances, such as fire‐prone ecosystems. Despite this, the role of movement in facilitating responses to fire has received little attention. Herein, we consider how animal movement interacts with fire history to shape species distributions. We consider how fire affects movement between habitat patches of differing fire histories that occur across a range of spatial and temporal scales, from daily foraging bouts to infrequent dispersal events, and annual migrations. We review animal movements in response to the immediate and abrupt impacts of fire, and the longer‐term successional changes that fires set in train. We discuss how the novel threats of altered fire regimes, landscape fragmentation, and invasive species result in suboptimal movements that drive populations downwards. We then outline the types of data needed to study animal movements in relation to fire and novel threats, to hasten the integration of movement ecology and fire ecology. We conclude by outlining a research agenda for the integration of movement ecology and fire ecology by identifying key research questions that emerge from our synthesis of animal movements in fire‐prone ecosystems.     

Effects of snout dimensions on the hydrodynamics of suction feeding in juvenile and adult seahorses

Seahorses give birth to juveniles having a fully functional feeding apparatus, and juvenile feeding behaviour shows striking similarities to that of adults. However, a significant allometric growth of the snout is observed during which the snout shape changes from relatively short and broad in juveniles to relatively long and slender in adults. Since the shape of the buccal cavity is a critical determinant of the suction performance, this snout allometry will inevitably affect the suction feeding ability. To test whether the snout is optimised for suction feeding throughout an ontogeny, we simulated the expansion of different snout shapes varying from extremely long and slender to short and broad for juvenile and adult snout sizes, using computational fluid dynamic models. Our results showed that the snout diameter at the start of the simulations is involved in a trade-off between the realizable suction volume and expansion time on the one hand (improving with larger initial diameters), and maximal flow velocity on the other hand (improving with smaller initial diameters). Moreover suction performance (suction volume as well as maximal attainable flow velocity) increased with decreasing snout length. However, an increase in snout length decreases the time to reach the prey by the cranial rotation, which may explain the prevalence of long snouts among syngnathid fishes despite the reduced suction performance. Thus, the design of the seahorse snout revolves around a trade-off between the ability to generate high-volume suction versus minimisation of the time needed to reach the prey by the cranial rotation.     

Downregulation of connexin40 and increased prevalence of atrial arrhythmias in transgenic mice with cardiac-restricted overexpression of tumor necrosis factor

Atrial arrhythmias, primarily atrial fibrillation, have been independently associated with structural remodeling and with inflammation. We hypothesized that sustained inflammatory signaling by tumor necrosis factor (TNF) would lead to alterations both in underlying atrial myocardial structure and in atrial electrical conduction. We performed ECG recording, intracardiac electrophysiology studies, epicardial mapping, and connexin immunohistochemical analyses on transgenic mice with targeted overexpression of TNF in the cardiac compartment (MHCsTNF) and on wild-type (WT) control mice (age 8-16 wk). Atrial and ventricular conduction abnormalities were always evident on ECG in MHCsTNF mice, including a shortened atrioventricular interval with a wide QRS duration secondary to junctional rhythm. Supraventricular arrhythmias were observed in five of eight MHCsTNF mice, whereas none of the mice demonstrated ventricular arrhythmias. No arrhythmias were observed in WT mice. Left ventricular conduction velocity during apical pacing was similar between the two mouse groups. Connexin40 was significantly downregulated in MHCsTNF mice. In contrast, connexin43 density was not significantly altered in MHCsTNF mice, but rather dispersed away from the intercalated disks. In conclusion, sustained inflammatory signaling contributed to atrial structural remodeling and downregulation of connexin40 that was associated with an increased prevalence of atrial arrhythmias.     

Can we rely on forest reserves for primate conservation?

Tropical forests contain much of the world's biodiversity, yet their rate of decline is increasing. The strategy most frequently used to protect this biodiversity is to make parks and reserves. While there is a great deal of research on the effectiveness of parks for protecting biodiversity, there is little research on how well extractive reserves conserve biodiversity. Here, we evaluate the effectiveness of four forest reserves in western Uganda at maintaining populations of primates and compare census data from the reserves to data from the neighbouring well‐protected Kibale National Park. The relative abundance of the five most common primates in the park was approximately four times that of the forest reserves. In the forest reserves, evidence of new human encroachment was seen every 500 m, while in the park it was seen every 100,000 m. Two recommendations emerge from our research: (i) for forest reserves, such as those studied here, to have conservation value for primates, extraction must be reduced and (ii) until the long‐term viability of the populations in forest reserves can be ascertained, they should not be considered in estimates of the sizes of endangered species protected ranges.     

Cold Shock Domain Containing E1 (CSDE1) Protein is Overexpressed and Can be Targeted to Inhibit Invasiveness in Pancreatic Cancer Cells

Pancreatic cancer has a dismal prognosis and to date there are no targeted therapies for this malignancy. Using shotgun proteomics, the mRNA binding protein cold shock domain containing E1 (CSDE1), also called upstream‐of‐N‐Ras, is detected in pancreatic cancer cell lines but not in normal pancreatic epithelial cells. The expression of CSDE1 in pancreatic cancer cells is confirmed by Western blotting and immunohistochemistry of human pancreatic tumors. In vitro functional assays show that siRNA downregulation of CSDE1 or gene knockout using CRISPR‐Cas9 significantly reduce the invasiveness of pancreatic cancer cells. Together, this study reveals that CSDE1 is overexpressed in pancreatic cancer and is a potential therapeutic target to inhibit pancreatic cancer cell invasion.