Establishing the ecological restoration network in Argentina: from Rio1992 to SIACRE2015

The development of the science and practice of restoration ecology in Argentina can be divided into three periods. The first was 1992–2004, characterized by isolated restoration efforts, mostly in arid and dry ecosystems, and engaging specific people in the academic, agro‐technological, and private sectors as partially required by national regulations, but also inspired by the 1992 Earth Summit, the 1994 Amendments of the Constitutional Law, and environmental guidelines from investment entities. The second period of 2005–2010 showed significantly greater involvement in international networking and conference contributions. The current period from 2011‐present has witnessed rapid advances and national integration. The country's network Red de Restauración Ecológica de Argentina (REA) was founded in 2012, with seven subnational nodes. In 2014, the 2nd REA symposium was held to determine priority areas for restoration and to generate a National Plan. Public agencies, NGOs and volunteer groups are now actively engaged stakeholders. In 2013 Argentina became a founder member of SIACRE (Sociedad Ibero‐Americana y del Caribe para la Restauración Ecológica) and is organizing SIACRE's 4th international conference (April 2015; Buenos Aires). Restoration ecology in Argentina is ascendant because of long‐term efforts related to strengthening democracy, people initiatives, and strong support from SIACRE, SER (Society for Ecological Restoration), SER‐Europe, and the national networks of Colombia, Brazil, Mexico, and Chile. Moreover, Argentina is now the first country to have updated its Civil Code by integrating the environment as a “legal good,” which reinforces the citizens' rights to demand the implementation of degradation prevention and/or ecosystem restoration measures.     

Is embryo abortion a post‐zygotic barrier to gene flow between Littorina ecotypes?

Genetic incompatibilities contribute to reproductive isolation between many diverging populations, but it is still unclear to what extent they play a role if divergence happens with gene flow. In contact zones between the "Crab" and "Wave" ecotypes of the snail Littorina saxatilis, divergent selection forms strong barriers to gene flow, while the role of post‐zygotic barriers due to selection against hybrids remains unclear. High embryo abortion rates in this species could indicate the presence of such barriers. Post‐zygotic barriers might include genetic incompatibilities (e.g. Dobzhansky–Muller incompatibilities) but also maladaptation, both expected to be most pronounced in contact zones. In addition, embryo abortion might reflect physiological stress on females and embryos independent of any genetic stress. We examined all embryos of >500 females sampled outside and inside contact zones of three populations in Sweden. Females' clutch size ranged from 0 to 1,011 embryos (mean 130 ± 123), and abortion rates varied between 0% and 100% (mean 12%). We described female genotypes by using a hybrid index based on hundreds of SNPs differentiated between ecotypes with which we characterized female genotypes. We also calculated female SNP heterozygosity and inversion karyotype. Clutch size did not vary with female hybrid index, and abortion rates were only weakly related to hybrid index in two sites but not at all in a third site. No additional variation in abortion rate was explained by female SNP heterozygosity, but increased female inversion heterozygosity added slightly to increased abortion. Our results show only weak and probably biologically insignificant post‐zygotic barriers contributing to ecotype divergence, and the high and variable abortion rates were marginally, if at all, explained by hybrid index of females.     

Examining post‐translational modification‐mediated protein–protein interactions using a chemical proteomics approach

Post‐translational modifications (PTM) of proteins can control complex and dynamic cellular processes via regulating interactions between key proteins. To understand these regulatory mechanisms, it is critical that we can profile the PTM‐dependent protein–protein interactions. However, identifying these interactions can be very difficult using available approaches, as PTMs can be dynamic and often mediate relatively weak protein–protein interactions. We have recently developed CLASPI (cross‐linking‐assisted and stable isotope labeling in cell culture‐based protein identification), a chemical proteomics approach to examine protein–protein interactions mediated by methylation in human cell lysates. Here, we report three extensions of the CLASPI approach. First, we show that CLASPI can be used to analyze methylation‐dependent protein–protein interactions in lysates of fission yeast, a genetically tractable model organism. For these studies, we examined trimethylated histone H3 lysine‐9 (H3K9Me₃)‐dependent protein–protein interactions. Second, we demonstrate that CLASPI can be used to examine phosphorylation‐dependent protein–protein interactions. In particular, we profile proteins recognizing phosphorylated histone H3 threonine‐3 (H3T3‐Phos), a mitotic histone “mark” appearing exclusively during cell division. Our approach identified survivin, the only known H3T3‐Phos‐binding protein, as well as other proteins, such as MCAK and KIF2A, that are likely to be involved in weak but selective interactions with this histone phosphorylation “mark”. Finally, we demonstrate that the CLASPI approach can be used to study the interplay between histone H3T3‐Phos and trimethylation on the adjacent residue lysine 4 (H3K4Me₃). Together, our findings indicate the CLASPI approach can be broadly applied to profile protein–protein interactions mediated by PTMs.     

Early post‐fire succession in northwestern Patagonia grasslands

Abstract. Large‐scale disturbances, notably fire and grazing, structure grass and shrubland dynamics in semi‐arid environments. We studied early post‐fire succession in two burned grasslands, one unburned grassland, and one shrubland near the burned area. We observed three processes: (1) establishment of a ‘phantom’ community comprised of fugitive species. Although transient, these species increase diversity and recharge the seed bank before the next disturbance; (2) regeneration of the original community by persistence of resprouter species and by auto‐replacement; (3) early stages of invasion by seedlings of the shrub Fabiana imbricata, which germinate next to shrubland and create new F. imbricata patches. Weed invasion was principally due to the ruderal exotic species Verbascum thapsus from the nearby road verge and by rapid increase of Rumex acetosella cover, another exotic species present before the fire. Although post‐fire climatic conditions are particularly important in semi‐arid environments, succession depends greatly on the regeneration strategies and dispersal abilities of the species present in the burned area. The phantom community occurs only at the first stage of succession when there is little competition for resources. We could call this process ‘the race for occupation of the area’. The second stage, when competition for resources becomes progressively more important, could be called ‘the effort to maintain space’.     

The ‘night shift’: nocturnal pollen‐transport networks in a boreal pine forest

1. Diurnal plant–visitor networks are well studied, but the community‐level dimension of nocturnal visitation by insects has been largely overlooked. 2. This study focused on the role of moths as pollen vectors in a boreal pine forest in Scotland. Light traps were used to sample moths in 20 plots in two consecutive years. The pollen on moths' bodies was identified and pollen grains counted. This information was used to build a nocturnal pollen‐transport network for each year. These are the first networks to characterise a nocturnal plant–visitor community. 3. A total of 4162 moths belonging to 103 species were captured; 25 moth species were found to carry pollen of 12 plant taxa. Adding nocturnal data to diurnal networks increased number of plant taxa, insect species, and unique interactions in the network. 4. Despite differences in species composition, nocturnal networks exhibit similar properties to diurnal networks: significant nestedness, marked asymmetry of interactions, high dependence on a core of generalists, and high inter‐annual variation in species abundances and occurrence of interactions. 5. Traditional diurnal plant–visitor networks exclude a significant component of the community, i.e. nocturnal visitors. Exploring links across boundaries between networks (such as between diurnal and nocturnal networks) will provide a more accurate picture of ecosystem structure and function.     

MeCP2 post‐translational regulation through PEST domains: two novel hypotheses

Mutations in the methyl‐CpG‐binding protein 2 (MeCP2) cause Rett syndrome, a severe neurodevelopmental disease associated with ataxia and other post‐natal symptoms similar to autism. Much research interest has focussed on the implications of MeCP2 in disease and neuron physiology. However, little or no attention has been paid to how MeCP2 turnover is regulated. The post‐translational control of MeCP2 is of critical importance, especially as subtle increases or decreases in MeCP2 amounts can affect neuron morphology and function. The latter point is of particular importance for gene therapeutic approaches in which exogenous wild‐type MeCP2 is being introduced into diseased neurons. Further to this, we propose two hypotheses. The first hypothesis discusses the poly‐ubiquitin‐mediated post‐translational regulation of MeCP2 through its two PEST domains. The second hypothesis explores the use of histone deacetylase inhibitors to modulate the amounts of MeCP2 expressed in conjunction with the aforementioned therapeutic approaches.     

Site quality effects on post‐fire regeneration of Pinus brutia forest on a Greek island

Abstract. Natural stands of Pinus brutia were compared to burned areas after a great fire in 1985 on the island of Thasos, North Greece, in relation to site quality effects on the success of natural regeneration and understorey vegetation. The number of seedlings in the natural stands of P. brutia was 1124/ha against 3188/ha in the burned area. In both cases natural regeneration was successful. Under the canopy of P. brutia forests the predominant shrubs were Quercus coccifera and vPhillyrea latifolia. A high percentage (up to 40%) of the total area was covered by these species. In the burned areas, 12 yr after the wildfire of 1985, Cistus incanus and C. salvifolius played a significant role in the survival of P. brutia seedlings. These species had covered the burned area long before the pine seed germination.     

Attraction of wild‐like and colony‐reared Bactrocera cucurbitae (Diptera:Tephritidae) to cuelure in the field

The attraction of wild tephritids to semiochemical‐based lures is the ideal basis for trap network design in detection programmes, but in practice, mass‐reared colony insects are usually used to determine trap efficiency. For Bactrocera cucurbitae Coquillett, a lower response by wild males compared with colony‐derived individuals, usually used to estimate attraction parameters, could mean that the sensitivity of detection networks targeting this pest is reduced. We describe the results of mark–release–recapture experiments with wild‐ and colony‐derived B. cucurbitae males in a grid of cuelure‐baited traps within a macadamia nut orchard in Hawaii Island designed to quantify the attraction of cuelure to each fly type. For colony males, we estimate a 65% probability of capture at 27 m, intermediate with previous estimates on the attraction of methyl eugenol to Bactrocera dorsalis Hendel (36 m) and trimedlure to Ceratitis capitata Wiedemann (14 m) at the same site. Results suggest similar response over distance by wild‐derived B. cucurbitae compared with colony in the field, but there may be qualitative differences in response between wild and colony based on very low response of wild males in a standard bioassay of attraction. For both fly types, the estimates of attraction in the smaller of two grid sizes tested were lower than for the larger spacing, suggesting trap competition was a factor at an intertrap distance of 75 m. Dispersal patterns within the grid were generally to the south for the colony‐derived males and more variable for the wild‐derived males. In neither case was the direction of recapture correlated with the prevailing direction of the wind.     

Abundance and generalisation in mutualistic networks: solving the chicken‐and‐egg dilemma

A frequent observation in plant–animal mutualistic networks is that abundant species tend to be more generalised, interacting with a broader range of interaction partners than rare species. Uncovering the causal relationship between abundance and generalisation has been hindered by a chicken‐and‐egg dilemma: is generalisation a by‐product of being abundant, or does high abundance result from generalisation? Here, we analyse a database of plant–pollinator and plant–seed disperser networks, and provide strong evidence that the causal link between abundance and generalisation is uni‐directional. Specifically, species appear to be generalists because they are more abundant, but the converse, that is that species become more abundant because they are generalists, is not supported by our analysis. Furthermore, null model analyses suggest that abundant species interact with many other species simply because they are more likely to encounter potential interaction partners.     

Not attackable or not crackable—How pre‐ and post‐attack defenses with different competition costs affect prey coexistence and population dynamics

It is well‐known that prey species often face trade‐offs between defense against predation and competitiveness, enabling predator‐mediated coexistence. However, we lack an understanding of how the large variety of different defense traits with different competition costs affects coexistence and population dynamics. Our study focusses on two general defense mechanisms, that is, pre‐attack (e.g., camouflage) and post‐attack defenses (e.g., weaponry) that act at different phases of the predator—prey interaction. We consider a food web model with one predator, two prey types and one resource. One prey type is undefended, while the other one is pre‐ or post‐attack defended paying costs either by a higher half‐saturation constant for resource uptake or a lower maximum growth rate. We show that post‐attack defenses promote prey coexistence and stabilize the population dynamics more strongly than pre‐attack defenses by interfering with the predator's functional response: Because the predator spends time handling “noncrackable” prey, the undefended prey is indirectly facilitated. A high half‐saturation constant as defense costs promotes coexistence more and stabilizes the dynamics less than a low maximum growth rate. The former imposes high costs at low resource concentrations but allows for temporally high growth rates at predator‐induced resource peaks preventing the extinction of the defended prey. We evaluate the effects of the different defense mechanisms and costs on coexistence under different enrichment levels in order to vary the importance of bottom‐up and top‐down control of the prey community.     

Preference of an exotic wood borer for stressed trees is more attributable to pre‐alighting than post‐alighting behaviour

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Angiotensin‐converting enzyme 2 in the brain: properties and future directions

Angiotensin (Ang)‐converting enzyme (ACE) 2 cleaves Ang‐II into the vasodilator peptide Ang‐(1–7), thus acting as a pivotal element in balancing the local effects of these peptides. ACE2 has been identified in various tissues and is supposed to be a modulator of cardiovascular function. Decreases in ACE2 expression and activity have been reported in models of hypertension, heart failure, atherosclerosis, diabetic nephropathy and others. In addition, the expression level and/or activity are affected by other renin–angiotensin system components (e.g., ACE and AT1 receptors). Local inhibition or global deletion of brain ACE2 induces a reduction in baroreflex sensitivity. Moreover, ACE2‐null mice have been shown to exhibit either blood pressure or cardiac dysfunction phenotypes. On the other hand, over‐expression of ACE2 exerts protective effects in local tissues, including the brain. In this review, we will first summarize the major findings linking ACE2 to cardiovascular function in the periphery then focus on recent discoveries related to ACE2 in the CNS. Finally, we will unveil new tools designed to address the importance of central ACE2 in various diseases, and discuss the potential for this carboxypeptidase as a new target in the treatment of hypertension and other cardiovascular diseases.     

Subnational greenhouse gas and land‐based biodiversity footprints in the European Union

Insights into subnational environmental impacts and the underlying drivers are scarce, especially from a consumption‐based perspective. Here, we quantified greenhouse gas (GHG) emissions and land‐based biodiversity losses associated with final consumption in 162 regions in the European Union in 2010. For this purpose, we developed an environmentally extended multi‐regional input–output (MRIO) model with subnational European information on demand, production, and trade structures subdivided into 18 major economic sectors, while accounting for trade outside Europe. We employed subnational data on land use and national data on GHG emissions. Our results revealed within‐country differences in per capita GHG and land‐based biodiversity footprints up to factors of 3.0 and 3.5, respectively, indicating that national footprints may mask considerable subnational variability. The per capita GHG footprint increased with per capita income and income equality, whereas we did not find such responses for the per capita land‐based biodiversity footprint, reflecting that extra income is primarily spent on energy‐intensive activities. Yet, we found a shift from the domestic to the foreign part of the biodiversity footprints with rising population density and income. Because our analysis showed that most regions are already net importers of GHG emissions and biodiversity losses, we conclude that it is increasingly important to address the role of trade in national and regional policies on mitigating GHG emissions and averting further biodiversity losses, both within and outside the region itself. To further increase the policy relevance of subnational footprint analyses, we also recommend the compilation of more detailed subnational MRIO databases including harmonized environmental data.     

Landscape‐scale accessibility of livestock to tigers: implications of spatial grain for modeling predation risk to mitigate human–carnivore conflict

Innovative conservation tools are greatly needed to reduce livelihood losses and wildlife declines resulting from human–carnivore conflict. Spatial risk modeling is an emerging method for assessing the spatial patterns of predator–prey interactions, with applications for mitigating carnivore attacks on livestock. Large carnivores that ambush prey attack and kill over small areas, requiring models at fine spatial grains to predict livestock depredation hot spots. To detect the best resolution for predicting where carnivores access livestock, we examined the spatial attributes associated with livestock killed by tigers in Kanha Tiger Reserve, India, using risk models generated at 20, 100, and 200‐m spatial grains. We analyzed land‐use, human presence, and vegetation structure variables at 138 kill sites and 439 random sites to identify key landscape attributes where livestock were vulnerable to tigers. Land‐use and human presence variables contributed strongly to predation risk models, with most variables showing high relative importance (≥0.85) at all spatial grains. The risk of a tiger killing livestock increased near dense forests and near the boundary of the park core zone where human presence is restricted. Risk was nonlinearly related to human infrastructure and open vegetation, with the greatest risk occurring 1.2 km from roads, 1.1 km from villages, and 8.0 km from scrubland. Kill sites were characterized by denser, patchier, and more complex vegetation with lower visibility than random sites. Risk maps revealed high‐risk hot spots inside of the core zone boundary and in several patches in the human‐dominated buffer zone. Validation against known kills revealed predictive accuracy for only the 20 m model, the resolution best representing the kill stage of hunting for large carnivores that ambush prey, like the tiger. Results demonstrate that risk models developed at fine spatial grains can offer accurate guidance on landscape attributes livestock should avoid to minimize human–carnivore conflict.     

Do‐or‐die life cycles and diverse post‐infection resistance mechanisms limit the evolution of parasite host ranges

In light of the dynamic nature of parasite host ranges and documented potential for rapid host shifts, the observed high host specificity of most parasites remains an ecological paradox. Different variants of host‐use trade‐offs have become a mainstay of theoretical explanations of the prevalence of host specialism, but empirical evidence for such trade‐offs is rare. We propose an alternative theory based on basic features of the parasite life cycle: host selection and subsequent intrahost replication. We introduce a new concept of effective burst size that accounts for the fact that successful host selection does not guarantee intrahost replication. Our theory makes a general prediction that a parasite will expand its host range if its effective burst size is positive. An in silico model of bacteria‐phage coevolution verifies our predictions and demonstrates that the tendency for relatively narrow host ranges in parasites can be explained even in the absence of trade‐offs.     

Mutualistic networks: moving closer to a predictive theory

Plant–animal mutualistic networks sustain terrestrial biodiversity and human food security. Global environmental changes threaten these networks, underscoring the urgency for developing a predictive theory on how networks respond to perturbations. Here, I synthesise theoretical advances towards predicting network structure, dynamics, interaction strengths and responses to perturbations. I find that mathematical models incorporating biological mechanisms of mutualistic interactions provide better predictions of network dynamics. Those mechanisms include trait matching, adaptive foraging, and the dynamic consumption and production of both resources and services provided by mutualisms. Models incorporating species traits better predict the potential structure of networks (fundamental niche), while theory based on the dynamics of species abundances, rewards, foraging preferences and reproductive services can predict the extremely dynamic realised structures of networks, and may successfully predict network responses to perturbations. From a theoretician's standpoint, model development must more realistically represent empirical data on interaction strengths, population dynamics and how these vary with perturbations from global change. From an empiricist's standpoint, theory needs to make specific predictions that can be tested by observation or experiments. Developing models using short‐term empirical data allows models to make longer term predictions of community dynamics. As more longer term data become available, rigorous tests of model predictions will improve.     

Neurovascular protection by post‐ischemic intravenous injections of the lipoxin A4 receptor agonist,BML‐111, in a rat model of ischemic stroke

Resolution of inflammation is an emerging new strategy to reduce damage following ischemic stroke. Lipoxin A₄ (LXA₄) is an anti‐inflammatory, pro‐resolution lipid mediator with high affinity binding to ALX, the lipoxin A₄ receptor. Since LXA₄ is rapidly inactivated, potent analogs have been created, including the ALX agonist BML‐111. We hypothesized that post‐ischemic intravenous administration of BML‐111 would provide protection to the neurovascular unit and reduce neuroinflammation in a rat stroke model. Animals were subjected to 90 min of middle cerebral artery occlusion (MCAO) and BML‐111 was injected 100 min and 24 h after stroke onset and animals euthanized at 48 h. Post‐ischemic treatment with BML‐111 significantly reduced infarct size, decreased vasogenic edema, protected against blood–brain barrier disruption, and reduced hemorrhagic transformation. Matrix metalloproteinase‐9 and matrix metalloproteinase‐3 were significantly reduced following BML‐111 treatment. Administration of BML‐111 dramatically decreased microglial activation, as seen with CD68, and neutrophil infiltration and recruitment, as assessed by levels of myeloperoxidase and intracellular adhesion molecule‐1. The tight junction protein zona occludens‐1 was protected from degradation following treatment with BML‐111. These results indicate that post‐ischemic activation of ALX has pro‐resolution effects that limit the inflammatory damage in the cerebral cortex and helps maintain blood–brain barrier integrity after ischemic stroke.

     

Seasonal changes in a cactus‐hoverfly (Diptera: Syrphidae) network

1. We analysed a cacti‐syrphid community focusing on the exploitation of decaying cacti resources by the flies, i.e. if exploitation exhibited a nested topology as a structural pattern, or whether it was temporally random. If availability of cactus resources was predictable during the rainy season, it would then be exploited by a more structured community, or as resource availability would be unpredictable during the dry season, we should expect it to be exploited by a random community. 2. We registered 12 Copestylum species (9 in dry and 11 in rainy season). Four cactus species were recorded per season, three were shared between seasons. 3. The community of Copestylum larvae in the rainy season was not randomly assembled but highly nested, revealing a highly structured pattern of resource use. It exhibited a random organization for the dry season. The high nestedness value obtained for the rainy season suggests that factors along with competition must play a major role in determining community structure. 4. Succession in the cacti‐syrphid community mediated by microorganisms involved in necrosis is an important factor structuring nested subsets. The studied networks were small, which may limit the power of the analysis, and strong conclusions could also be limited.