Natural Colonization Research Articles

Predator effects on a detritus‐based food web are primarily mediated by non‐trophic interactions

Predator effects on ecosystems can extend far beyond their prey and are often not solely lethally transmitted. Change in prey traits in response to predation risk can have important repercussions on community assembly and key ecosystem processes (i.e. trait-mediated indirect effects). In addition, some predators themselves alter habitat structure or nutrient cycling through ecological engineering effects. Tracking these non-trophic pathways is thus an important, yet challenging task to gain a better grasp of the functional role of predators. Multiple lines of evidence suggest that, in detritus-based food webs, non-trophic interactions may prevail over purely trophic interactions in determining predator effects on plant litter decomposition. This hypothesis was tested in a headwater stream by modulating the density of a flatworm predator (Polycelis felina) in enclosures containing oak (Quercus robur) leaf litter exposed to natural colonization by small invertebrates and microbial decomposers. Causal path modelling was used to infer how predator effects propagated through the food web. Flatworms accelerated litter decomposition through positive effects on microbial decomposers. The biomass of prey and non-prey invertebrates was not negatively affected by flatworms, suggesting that net predator effect on litter decomposition was primarily determined by non-trophic interactions. Flatworms enhanced the deposition and retention of fine sediments on leaf surface, thereby improving leaf colonization by invertebrates - most of which having strong affinities with interstitial habitats. This predator-induced improvement of habitat availability was attributed to the sticky nature of the mucus that flatworms secrete in copious amount while foraging. Results of path analyses further indicated that this bottom-up ecological engineering effect was as powerful as the top-down effect on invertebrate prey. Our findings suggest that predators have the potential to affect substantially carbon flow and nutrient cycling in detritus-based ecosystems and that this impact cannot be fully appreciated without considering non-trophic effects.

科尔沁草原区火电厂储灰池植被恢复过程中白草种群分蘖株的年龄结构

植被恢复过程中优势植物种群的年龄结构对于演替动态的预测具有重要的作用。通过对科尔沁草原区火电厂不同恢复年限储灰池植被恢复过程中白草种群分蘖株年龄结构、分蘖节芽年龄结构、分蘖株的物质生产力及营养繁殖力的比较研究，分析了不同恢复年限（1区：1992-1993年恢复；2区：1996-1997年恢复：3区：1999-2000年恢复）和家畜干扰条件下（2005年开始）白草分蘖株结构的变化。结果表明：2003年围栏时，随着恢复年限的增长，3个储灰池中白草分蘖株数量和生物量的龄级构成以增长型为主；2007年时，两年不同程度的家畜干扰后，3个储灰池中白草分蘖株数量和生物量均为稳定型结构。2007年各龄级白草分蘖节芽及其总量均显著高于2003年。2003年围栏时，3个储灰池中白草分蘖株的物质生产力在同一龄级间均无显著差异；2007年家畜干扰后，2区和3区中1a分蘖株和总体均值的物质生产力均显著低于2003年。2003年围栏时，3区中1a分蘖株和总体均值的营养繁殖力均显著高于1区和2区；2007年家畜干扰后，3区中1a、3a分蘖株和总体均值的营养繁殖力均显著低于1区和2区；2007年各龄级分蘖株及总体均值的营养繁殖力均高于2003年，各恢复区1a、1区2a和各区分蘖株营养繁殖力的均值在两个取样年间的差异均达到显著水平。继续围栏保护对于本研究中火电厂储灰池的植被恢复是切实可行而有效的管理措施。;Age structure of dominant plant populations is vital to forecast community dynamics during vegetation restoration. <em>Pennisetum flaccidum</em>, a perennial grass with long rhizomes, is widely distributed in the northeast and western regions as well as the Inner Mongolian Plateau of China. In the Kerqin grassland region, <em>P. flaccidum </em>is one of several native plant species that are used to restore coal ash storage pools generated by Coal Power Plants. In 2003, we located three ash storage pools (from here on referred to as‘plots’) that differed in age (12, 8, and 5 years old) and contained <em>P. flaccidum</em>. We found that natural colonization had successfully restored these plots, with the average herbaceous cover for all three plots reaching 85%-90%. We sampled the <em>P. flaccidum</em> population. Due to relaxed oversight at the storage pools following a change in the managing entity in 2005, the plots were grazed by livestock. In 2007, we resampled the same plots and found that the total vegetation coverage had decreased to 30%-50%.<br>In late August of 2003 and 2007, three to five replicate quadrats (each 0.25 x 0.25 m in area and 50 cm deep) in each plot were sampled by taking soil cores, including all aboveground shoots and belowground rhizomes, to maintain the inherent links among tillers and rhizomes. Age classes of tillers and tillering buds were classified according to vegetative propagation generations of tillering nodes and their numbers were counted. Age structure of tillers, tiller buds, tiller matter productivity and tiller vegetative propagation capability of <em>P. flaccidum</em> populations were studied during different vegetation restoration years in the coal ash storage plots of Coal Power Plant in the Kerqin grassland region. Structure changes of <em>P. flaccidum</em> tillers were analyzed under different restoration years (spot 1: 1992-1993; spot 2: 1996-1997; spot 3: 1999-2000) and livestock disturbance (the beginning of 2005). Number and biomass of <em>P. flaccidum</em> tillers showed expanding age structures in both spot 1 and spot 2 and it was stable in spot 3 in 2003. After two years livestock disturbed with different intensities since 2005, <em>P. flaccidum</em> tillers showed stable age structures in all three spots. Every age class and total tiller buds were significantly higher in 2007 after disturbing than those in 2003 as enclosed. Dry matter productivity of same age class tillers was not significantly different among three spots in 2003. Dry matter productivity of 1a tillers and average of each age class in spot 2 and spot 3 in 2007 were significantly fewer than those in 2003. Vegetative propagation capability of tillers of both 1a and average of all age classes were all higher in spot 3 than those in spot 1 and spot 2 in 2003 (<em>P</em>< 0.05). Vegetative propagation capability of tillers of 1a, 3a and average of all age classes in spot 3 were all significantly fewer than those in spot 1 and spot 2 in 2007 after livestock disturbance. Vegetative propagation capability of every age class tillers and their average value in 2007 was higher than those in 2003. There were significant differences between 2003 and 2007 at vegetative propagation capability of 1a age class tillers in every spot, 2a age class tillers in spot 1 and average vegetative propagation capability. Sustaining fence to coal ash storage pools of Coal Power Plant is an effective way to vegetation restoration in the arid Kerqin grassland region.

Effect of seasonal variation on arbuscular mycorrhizal fungi associated with date palm

Effect of seasonal variation of arbuscular mycorrhizal fungi (AMF) on diversity of species population was assessed in the Tafilalet date palm groves. Root colonization level, mean spore density and species diversity were measured during the wet and dry seasons. The root colonization level was strongly influenced by edaphic factors and plant phenological events; whereas, the spore population was dependent on water availability. Fifteen arbuscular mycorrhizal fungi species from genera Glomus, Acaulospora and Scutellospora were detected in Tafilalet date palm groves. Among them, 60% of the species population was represented by the genus Glomus. The natural root colonization and the diversity of AMF species associated with date palm suggest the applicability of mycorrhizal symbiosis in the management of date palm nurseries and grove establishment.

Examination of the Anaerobic Growth of Campylobacter concisus Strains.

Campylobacter concisus is an oral bacterium that is associated with intestinal diseases. C. concisus was previously described as a bacterium that requires H2-enriched microaerobic conditions for growth. The level of H2 in the oral cavity is extremely low, suggesting that C. concisus is unlikely to have a microaerobic growth there. In this study, the anaerobic growth of C. concisus was investigated. The growth of fifty-seven oral C. concisus strains and six enteric C. concisus strains under various atmospheric conditions including anaerobic conditions with and without H2 was examined. The atmospheric conditions were generated using commercially available gas-generation systems. C. concisus putative virulence proteins were identified using mass spectrometry analysis. Under anaerobic conditions, 92% of the oral C. concisus strains (52/57) and all six enteric strains grew without the presence of H2 and the presence of H2 greatly increased C. concisus growth. An oral C. concisus strain was found to express a number of putative virulence proteins and the expression levels of these proteins were not affected by H2. The levels of H2 appeared to affect the optimal growth of C. concisus. This study provides useful information in understanding the natural colonization site and pathogenicity of C. concisus.

Isolated and vulnerable: the history and future of Pacific Island terrestrial biodiversity

Islands in the tropical Pacific have a rich and unique biota produced by island biogeographic processes and modified by recent anthropogenic influences. This biota has been shaped by four overlapping phases: natural colonization and dynamics (phase 1), impacts of indigenous (phase 2) and non-indigenous (phase 3) settlers, and increasing environmental awareness (phase 4). Island ecosystems are resilient to natural disturbance regimes but highly vulnerable to invasive species and other human-related influences, due to comparatively low alpha diversity, isolated evolution and the absence of certain functional groups. Habitat loss, overexploitation, invasive alien species and pollution continue to threaten terrestrial biodiversity, compounded by limited environmental awareness, minimal conservation funding, project mismanagement, limited local capacity and inadequate and/or unsuitable conservation policies. To achieve effective conservation of terrestrial biodiversity in the region, biophysical threats need to be mitigated with improved scientific, institutional and management capacity.

Recovery rate of vegetation in the tsunami impacted littoral forest of Nicobar Islands, India

The interplay between disturbance and recovery has implications in understanding the dynamics of tropical forests. The high magnitude earthquake of 9.3Mw and the subsequent tsunami in Indian Ocean had severe impacts on the coastal biodiversity of Southeast Asia. Close vicinity of the Nicobar Islands to the earthquake epicenter has been attributed to the maximum damage levels in terms of coastal biodiversity as well as human lives. Littoral forests that are important for the survival of many endemic flora and fauna of Nicobar Islands were badly affected. We studied the recovery of littoral forest tree community from 25 sites on eight islands in Nicobar group during 2009–2011 where the tsunami had wiped out all the vegetation. Changes in woody plants⩾3.2cm Diameter at breast height (DBH) were monitored for 62 plots of 50×20m (0.1ha.) for two consecutive years, 2009–2010 and 2010–2011. Two kinds of regenerating vegetation were identified namely, Rubble-affected Vegetation (RV) where substrate was found deposited with sand and coral rubbles during tsunami and Loamy Vegetation (LV) where the substrate remained as sand-loamy without any deposition. A total of 5528 tree individuals of 120 species and a total of 5843 tree individuals of 127 species were recorded during the first and the second year, respectively. Species diversity was high in the second year for both the vegetation types, where LV with 120 species had higher species diversity than RV (43 species). The species composition differed among vegetation types. Macaranga peltata and Ficus hispida were dominant in LV, and Casuarina equisetifolia and Hibiscus tiliaceus were dominant in RV. Mean species richness, stem density and basal area plot−1 varied significantly between RV and LV (P<0.0001). LV showed higher values for variables than RV. The values for all the variables increased during the second year, except for stem density in LV and show significant differences between the years for RV and LV (P<0.01). Species richness plot−1 in LV may reach the mature forest value in two years if the species accumulation proceeds at the observed rate. We inferred that the natural recovery of vegetation was higher in the soil substratum unaffected LV than the debris deposited RV. Hence, the restoration of soil at RV sites is important for promoting the natural colonization of pioneer and old-growth forest species. Continuous monitoring of these plots may provide useful information on the long lasting impacts and recovery of littoral forest after tsunami.

Genetic structure of pike (Esox lucius) reveals a complex and previously unrecognized colonization history of Ireland.

AimWe investigated genetic variation of Irish pike populations and their relationship with European outgroups, in order to elucidate the origin of this species to the island, which is largely assumed to have occurred as a human-mediated introduction over the past few hundred years. We aimed thereby to provide new insights into population structure to improve fisheries and biodiversity management in Irish freshwaters.LocationIreland, Britain and continental Europe.MethodsA total of 752 pike (Esox lucius) were sampled from 15 locations around Ireland, and 9 continental European sites, and genotyped at six polymorphic microsatellite loci. Patterns and mechanisms of population genetic structure were assessed through a diverse array of methods, including Bayesian clustering, hierarchical analysis of molecular variance, and approximate Bayesian computation.ResultsVarying levels of genetic diversity and a high degree of population genetic differentiation were detected. Clear substructure within Ireland was identified, with two main groups being evident. One of the Irish populations showed high similarity with British populations. The other, more widespread, Irish strain did not group with any European population examined. Approximate Bayesian computation suggested that this widespread Irish strain is older, and may have colonized Ireland independently of humans.Main conclusionsPopulation genetic substructure in Irish pike is high and comparable to the levels observed elsewhere in Europe. A comparison of evolutionary scenarios upholds the possibility that pike may have colonized Ireland in two ‘waves’, the first of which, being independent of human colonization, would represent the first evidence for natural colonization of a non-anadromous freshwater fish to the island of Ireland. Although further investigations using comprehensive genomic techniques will be necessary to confirm this, the present results warrant a reappraisal of current management strategies for this species.

Nematophagous fungi: Catenaria anguillulae and Dactylaria brochopaga from seed galls as potential biocontrol agents of Anguina tritici and Meloidogyne graminicola in wheat (Triticum aestivum L.)

During the course of our investigation on the selective isolation and in vitro pathogenicity tests of the nematode egg parasite and endoparasitic Catenaria anguillulae and the nematode-trapping fungus Dactylaria brochopaga against Anguina tritici, and Meloidogyne graminicola, the two biocontrol agents were also examined for their capabilities to colonize wheat seed gall and also to reduce the M. graminicola, and A. tritici in wheat (Triticum aestivum L.). Using seed galls as bait was found effective for isolating the soilborne natural colonizers of seed galls of wheat caused by A. tritici. Seed galls were found severely infested with cellulose decomposers as well as nematode trapping fungi i.e., Fusarium spp., Verticillium spp., Aspergillus spp., Penicillium spp. Arthrobotrys oligospora, Arthrobotrys superba, Arthrobotrys dactyloides, Arthrobotrys musiformis, D. brochopaga, Monacrosporium eudermatum, Stylopaga hadra, Paecilomyces spp., and C. anguillulae. Co-inoculation of D. brochopaga DBS-105, and C. anguillulae CAS101 significantly reduced the root knot and seed gall in wheat and increased the plant growth parameters including length, and dry weight of root and shoot as well as yield attributing characters like spike length; number of seed per spike, test weight etc. under greenhouse conditions as compared to pathogen challenged plants without any bioagents/chemical nematicide. These bioagents have the potential to enhance production of quality seeds of wheat being free from hazardous pesticides and thus, can further be developed into marketable formulations in order to promote eco-friendly and sustainable means of crop production.

Coral Colonisation of an Artificial Reef in a Turbid Nearshore Environment, Dampier Harbour, Western Australia

A 0.6 hectare artificial reef of local rock and recycled concrete sleepers was constructed in December 2006 at Parker Point in the industrial port of Dampier, western Australia, with the aim of providing an environmental offset for a nearshore coral community lost to land reclamation. Corals successfully colonised the artificial reef, despite the relatively harsh environmental conditions at the site (annual water temperature range 18-32°C, intermittent high turbidity, frequent cyclones, frequent nearby ship movements). Coral settlement to the artificial reef was examined by terracotta tile deployments, and later stages of coral community development were examined by in-situ visual surveys within fixed 25 x 25 cm quadrats on the rock and concrete substrates. Mean coral density on the tiles varied from 113 ± 17 SE to 909 ± 85 SE per m2 over five deployments, whereas mean coral density in the quadrats was only 6.0 ± 1.0 SE per m2 at eight months post construction, increasing to 24.0 ± 2.1 SE per m2 at 62 months post construction. Coral taxa colonising the artificial reef were a subset of those on the surrounding natural reef, but occurred in different proportions— Pseudosiderastreatayami , Mycediumelephantotus and Leptastrea purpurea being disproportionately abundant on the artificial reef. Coral cover increased rapidly in the later stages of the study, reaching 2.3 ± 0.7 SE % at 62 months post construction. This study indicates that simple materials of opportunity can provide a suitable substrate for coral recruitment in Dampier Harbour, and that natural colonisation at the study site remains sufficient to initiate a coral community on artificial substrate despite ongoing natural and anthropogenic perturbations.

Adapting restoration and management to climate change

Adapting restoration and management to climate change

Reduction of nutrient contaminants into shallow eutrophic waters through vegetated treatment beds

One of the most effective mitigative approaches to eutrophication is the reduction of nutrient loading into water bodies. Bioremediation presents an economically viable and ecologically sustainable technology to nutrient pollution control taking advantage of the remarkable ability of plants and their associated microbial community to assimilate and remove nutrients from the environment. In this study, four emergent macrophytes (Cyperus haspan, Pandanus amaryllifolius, Pontederia cordata and Thalia geniculata) and two floating plants (Hygroryza aristata and Pistia stratiotes) were deployed in bank-side treatment beds and comparatively assessed for their remediative capabilities for nutrient control. P. stratiotes exhibited the highest removal efficiency for both nitrate and phosphate among the six plant species studied. Emergent macrophytes, P. amaryllifolius, C. haspan and P. cordata, were also found to be highly effective in nutrient uptake exhibiting removal efficiencies up to 100%. With the exception of T. geniculata, depletion of nutrients as a result of plant uptake significantly impeded the natural colonization of algae invariably leading to improvements in water quality in terms of turbidity and pH. Suppression of algae proliferation by T. geniculata was not preceded by a reduction in nutrient concentrations suggesting that T. geniculata may be directly inhibiting algal growth through allelopathy.

Genetic variation in brown trout Salmo truttaacross the Danube, Rhine, and Elbe headwaters: a failure of the phylogeographic paradigm?

BackgroundBrown trout Salmo trutta have been described in terms of five major mtDNA lineages, four of which correspond to major ocean basins, and one, according to some authors, to a distinct taxon, marbled trout Salmo marmoratus. The Atlantic and Danubian lineages of brown trout meet in a poorly documented contact zone in Central Europe. The natural versus human mediated origin of the Atlantic lineage in the upper Danube is a question of both theoretical and practical importance with respect to conservation management. We provide a comprehensive population genetic analysis of brown trout in the region with the aim of evaluating the geographic distribution and genetic integrity of these two lineages in and around their contact zone.ResultsGenetic screening of 114 populations of brown trout across the Danube/Rhine/Elbe catchments revealed a counter-intuitive phylogeographic structure with near fixation of the Atlantic lineage in the sampled portions of the Bavarian Danube. Along the Austrian Danube, phylogeographic informative markers revealed increasing percentages of Danube-specific alleles with downstream distance. Pure Danube lineage populations were restricted to peri-alpine isolates within previously glaciated regions. Both empirical data and simulated hybrid comparisons support that trout in non-glaciated regions north and northeast of the Alps have an admixed origin largely based on natural colonization. In contrast, the presence of Atlantic basin alleles south and southeast of the Alps stems from hatchery introductions and subsequent introgression. Despite extensive stocking of the Atlantic lineage, little evidence of first generation stocked fish or F1 hybrids were found implying that admixture has been established over time.ConclusionsA purely phylogeographic paradigm fails to describe the distribution of genetic lineages of Salmo in Central Europe. The distribution pattern of the Atlantic and Danube lineages is extremely difficult to explain without invoking very strong biological mechanisms.The peri-alpine distribution of relict populations of pure Danubian lineage brown trout implies that they colonized headwater river courses post-glacially ahead of the expansion of the Atlantic lineage. The recognition of natural as opposed to anthropogenic introgression of the Atlantic lineage into Danubian gene pools is of fundamental importance to management strategies.

Conservación y gestión cinegética del corzo en Andalucía

San Jose, C., Fernandez-Salguero, P., Redondo, I. (2013). Conservation and game management of roe deer in Andalusia. Ecosistemas 22(2):20-26. Doi.: 10.7818/ECOS.2013.22-2.04 At present roe deer distribution in Andalusia is limited to two population nuclei separated by the Guadalquivir River. The first one, more threatened by demographic extinction, is located in Sierra Morena, between Ciudad Real, Cordoba and Jaen provinces. The second one, relatively well conserved, is located in the mountainous zones of Cadiz-Malaga. The roe deer disappeared from many Andalusian areas mainly due to the disappearing of the suitable habitat for the species and to the increase of other wild and domestic ungulate populations. The studies carried out over the last 25 years on the Andalusian roe deer populations of Cadiz-Malaga revealed the existence of an ecotype native to the mountainous zones of these two Andalusian provinces, which presents significant differences on a morphological and genetic level with respect to other Spanish and European roe deer populations, and which was recently catalogued by the CIC (International Council for Game and Wildlife Conservation) as a singular trophy. Taking into account all these particularities, roe deer management in Andalusia is focused on two main objectives: 1) the conservation of the Andalusian ecotype native to the mountainous areas of Cadiz-Malaga, and 2) guaranteeing a good level of conservation of the current Andalusian habitat suitable for roe deer, as well as improving the potentially optimal areas for natural colonization by roe deer or potential reintroductions of the species in Andalusia.

In Vivo Adaptation and Persistence of Neisseria meningitidis within the Nasopharyngeal Mucosa

Neisseria meningitidis (Nme) asymptomatically colonizes the human nasopharynx, yet can initiate rapidly-progressing sepsis and meningitis in rare instances. Understanding the meningococcal lifestyle within the nasopharyngeal mucosa, a phase of infection that is prerequisite for disease, has been hampered by the lack of animal models. Herein, we compare mice expressing the four different human carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) that can bind the neisserial Opa protein adhesins, and find that expression of human CEACAM1 is necessary and sufficient to establish intranasal colonization. During infection, in vivo selection for phase variants expressing CEACAM1-specific Opa proteins occurs, allowing mucosal attachment and entry into the subepithelial space. Consistent with an essential role for Opa proteins in this process, Opa-deficient meningococci were unable to colonize the CEACAM1-humanized mice. While simple Opa-mediated attachment triggered an innate response regardless of meningococcal viability within the inoculum, persistence of viable Opa-expressing bacteria within the CEACAM1-humanized mice was required for a protective memory response to be achieved. Parenteral immunization with a capsule-based conjugate vaccine led to the accumulation of protective levels of Nme-specific IgG within the nasal mucus, yet the sterilizing immunity afforded by natural colonization was instead conferred by Nme-specific IgA without detectable IgG. Considered together, this study establishes that the availability of CEACAM1 helps define the exquisite host specificity of this human-restricted pathogen, displays a striking example of in vivo selection for the expression of desirable Opa variants, and provides a novel model in which to consider meningococcal infection and immunity within the nasopharyngeal mucosa.

FORUM: Challenges and future directions in urban afforestation

SummaryMature urban trees improve air quality, reduce storm water run‐off and sequester carbon. Municipal agencies establish forests of native juvenile trees to enhance these and other ecosystem services to cities. Little data exist, however, regarding whether these trees will form mature, native forests.We review urban forestry research that deals specifically with the growth, survival and recruitment of new native urban forests and use these data to identify knowledge gaps and propose research needed to create and maintain native urban forests.Experimental urban forestry studies are few and most are of durations ≤5 years, shorter than the 10–25 year time frame required to understand forest stand dynamics. Studies capturing initial dynamics of urban afforestation (≤5 years) identify invasive species as the primary threat to native tree establishment. Data exploring longer‐term dynamics are needed to evaluate whether early‐stage afforestation dynamics can be used to infer the composition and function of mature urban forests.Synthesis and applications. Urban afforestation approaches – from natural colonization to large‐scale plantings – represent a trade‐off in cost vs. efficacy for establishing native forests. A major cost‐saving strategy would be to determine whether exotics and natives can co‐exist and provide the intended ecosystem services.

Effect of GAC pre-treatment and disinfectant on microbial community structure and opportunistic pathogen occurrence

Opportunistic pathogens in potable water systems are an emerging health concern; however, the factors influencing their proliferation are poorly understood. Here we investigated the effects of prior granular activated carbon (GAC) biofiltration [GAC-filtered water, unfiltered water, and a blend (30% GAC filtered and 70% unfiltered water)] and disinfectant type (chlorine, chloramine) on opportunistic pathogen occurrence using five annular reactors (ARs) to simulate water distribution systems, particularly premise plumbing. GAC pre-treatment effectively reduced total organic carbon (TOC), resulting in three levels of influent TOC investigated. Quantitative polymerase chain reaction (q-PCR) provided molecular evidence of natural colonization of Legionella spp., Mycobacterium spp., Acanthamoeba spp., Hartmannella vermiformis and Mycobacterium avium on AR coupons. Cultivable mycobacteria and amoeba, including pathogenic species, were also found in bulk water and biofilm samples. While q-PCR tends to overestimate live cells, it provided a quantitative comparison of target organisms colonizing the AR biofilms in terms of gene copy numbers. In most cases, total bacteria and opportunistic pathogens were higher in the three undisinfected ARs, but the levels were not proportional to the level of GAC pre-treatment/TOC. Chlorine was more effective for controlling mycobacteria and Acanthamoeba, whereas chloramine was more effective for controlling Legionella. Both chlorine and chloramine effectively inhibited M. avium and H. vermiformis colonization. Pyrosequencing of 16S rRNA genes in coupon biofilms revealed a significant effect of GAC pre-treatment and disinfectant type on the microbial community structure. Overall, this study provides insights into the potential of different disinfectants and GAC biofilters at the treatment plant and in buildings to control downstream opportunistic pathogens and broader drinking water microbial communities.

Structure and conservation value of high-diversity hedgerows in southeastern Brazil

We studied the tree component of hedgerows resulting from the natural colonization of land plot boundaries’ ditches. These three-meter wide ditches were dug during the European occupation of southeastern Brazil, and are a prominent feature of the landscape. The hedgerows are connected to forest fragments within a farmland matrix. In two systems of hedgerows, we sampled a total of 2.28 ha (114 plots of 200 m²), where we evaluated the structural and floristic similarity between fragments and hedgerows, the similarities between the hedgerows and the fragments’ edges and interior, and the relationships between distribution of tree species and soil variables. The systems presented similar richness and diversity; hedgerows had greater similarity to the fragments included in the same system than to hedgerows of the other system, indicating possible functional linkages between their components (fragments and hedgerows). Tree species composition in the hedgerows was not more similar to the fragment edges as we expected. The hedgerows exhibited greater density and basal area than the fragments. For either single system, species showed preferences for fragments or hedgerows or for sections of the ditch (edge, wall and bottom of the ditch), but for species common in both systems, those preferences were rarely held. The environmental conditions in the ditches seem to favor the establishment of species from the fragments, even those more common in fragment interior, suggesting that, in spite of their narrow widths, these hedgerows may play an important role in the conservation of flora without negatively impacting agriculturally productive rural areas.

Evaluation of chemical parameters and ecotoxicity of a soil developed on gossan following application of polyacrylates and growth of Spergularia purpurea

The aim of this study was to evaluate the chemical characteristics and ecotoxicity of a mine soil developed on gossan materials and amended with hydrophilic polyacrylate polymers after a growth cycle of Spergularia purpurea. Different acute bioassays (Daphnia magna immobilization; microalgae growth inhibition; germination and growth of lettuce and oat) were carried out with simulated leachates, pore water and soil samples. The germination and growth of native shrubs (Cistus ladanifer and Lavandula sampaioana) were also evaluated in the lysimeters where S. purpurea had grown.The soil had high total concentrations (g/kg) of Al (3.50–8.60), As (2.55–2.73), Cu (0.13–0.91) and Pb (4.48–6.16). However, the percentages of elements in aqueous extracts (simulating leachates, pore water, and the conditions of the rhizosphere soil) were small when compared to their total soil concentrations (less than 9% except for Na in leachates). Growth of S. purpurea and other natural colonization of plant species (Poaceae, Fabaceae and Asteraceae families) improved chemical characteristics but the application of the polyacrylate polymers contributed to a further improvement of soil quality. However, this was not sufficient to ensure the growth of a large number of shrubs despite a great germination rate.Among the several species used on the ecotoxicological assessment, the D. magna test was the only bioassay that showed a clear toxicity of soil leachates, suggesting the importance of using several ecotoxicological tests to assess the environmental risk of soil contamination and its rehabilitation.Although the studied soil can be considered contaminated taking into account the total soil concentrations of Al, As, Cu and Pb, the low concentrations of the same chemical elements in extractable solutions, that simulated the fractions really available for organisms, did not demonstrate a substantial toxic effects in the organisms and, consequently, negative impact on the environment.

Scales and drivers of local adaptation in Brassica nigra (Brassicaceae) populations

Although there is much empirical evidence for local adaptation in plant populations, spatial scales and drivers are still poorly understood. We used the annual species Brassica nigra to (1) test scales of differentiation and adaptation among coastal wetland and inland river-valley populations and (2) analyze herbivory as a potential driver of local plant adaptation. • In a common garden experiment, we compared seven populations collected at different geographic scales in both habitat types. To evaluate adaptation to herbivory, we removed the aphid Brevicoryne brassicae from half of the plants. In a reciprocal transplant experiment, we tested local adaptation in two coastal and two river-valley populations. Natural colonization by dominant herbivore species was recorded. • In the common garden, the river-valley populations showed a higher performance than the coastal ones, whereas large-scale differentiation within habitats was small. Such a differentiation among plant populations was also found in spontaneous infestation by several herbivore groups but not in the plant response to aphid removal. In the reciprocal transplant experiment at natural sites, both plant populations performed better in their home habitat, indicating local adaptation to environmental differences between coastal and river-valley sites. A lower aphid infestation on local plants suggests a contribution of herbivores to local plant adaptation and illustrates the need for reciprocal transplant experiments to evaluate this contribution. • Our study demonstrates that adaptive differentiation among habitats may be stronger at relatively small scales than large-scale adaptation within these habitats. It provides new insights into the role of herbivory in driving local plant adaptation.

Sustainable Tourism: Whale Watching Footprint in the Bahía de Banderas, México

ABSTRACT Cornejo-Ortega, J.L.; Chavez-Dagostino, R.M., and Massam, B.H., 2013. Sustainable tourism: whale watching footprint in the Bahia de Banderas, Mexico. The discussion about nonsustainable ecological systems is in vogue. The debate has led to the biophysical analysis of “human-nature” relationships. This analysis is an important way to determine human impacts on the Earth, based on the colonization of nature and social activities that consider matter and energy flows through appropriation, transformation, distribution, consumption, and excretion. Tourism has appropriated and characterized various types of ecosystems that represent the use of a finite set of spatially distributed resources. The observation of marine mammals, such as whales, in natural protected areas attracts many tourists each year, and this activity indirectly generates carbon dioxide that is released into the atmosphere. This carbon emission, which is accompanied by the increased scale of tourism, may hamper global conservation go...