Litter production plays an important role in the functioning of the ecosystem, providing several ecosystem services, such as nutrients cycling and carbon storage. We studied litter production patterns and its relationship with forest structure over a chronosequence of secondary forests in southern Bahia, Brazil. In the study area, 15 pairs of mature and secondary forest were used, in a chronological sequence, being 10, 25 and 40-year-old secondary forests and mature forests. Plots were created for the collection of aboveground biomass data, and within these plots, litter collectors were installed and monitored for 1 year. The results showed that litter production was lower in 10-year-old secondary forests when compared with older forests. On the other hand, in the 10-year-old forests, annual litter production represents 47.8% of the stored biomass, while in mature forests annual litter production represents only 4%. We found that structural variables (basal area, number of stems and canopy opening) influence significantly litter production, as well as litter as percentage of forest biomass. The study emphasizes the importance of biomass production through litterfall in regenerating tropical forests, and its importance for carbon storage and for the maintenance of ecosystem services.

Litter breakdown is an important ecological process at the bottom of food webs in streams. Previous studies have been based only on a temporal interval of a single season, thus ignoring seasonal variation in litter input and community structure. We investigated organic matter input in a Brazilian savanna stream and the influence of its associated hyphomycetes on the invertebrate community. Organic matter input was sampled monthly and the leaves submitted to decomposition experiments. There were lower breakdown rates and higher invertebrate species richness and abundance during the dry season, which reached their maximum in July due to low stream discharge. Invertebrate composition was best explained by hyphomycetes (mainly by Flagellospora curvula and Anguillospora filiformis). Hyphomycetes have the capacity to degrade complex compounds of litter and to rapidly absorb nutrients by growing branched filaments, thus making the leaves more favourable for consumption by invertebrates. Shredder abundance was negatively related to litter richness, indicating possible species-specific relationships. We observed a sequential process with increased leaf litter input promoting an increase in hyphomycetes biomass, which in turn favoured invertebrate density.

The negative effects of invasive plant species on native ecosystems, which can be large and long-lasting, are the primary justifications for their research and management. Tremendous effort is focused on quantifying the ecological impacts of invasive plants, though two different methods are primarily used: observational (compare invaded and uninvaded) and removals (compare invaded and invader removal). However, it is unknown whether these methods, which differ in their assumptions and execution, yield similar results, which could affect our ability to draw broad conclusions within and across studies. Therefore, we performed a meta-analysis on 174 studies that described 547 impacts of 72 invasive plants to test the effect of study method, invader cover, and removal period on the direction and magnitude of impact. Overall, by only considering impact magnitude and not direction, both observational and removal methods yielded similar results—invasive plants are changing most aspects of the ecosystem—and the variation among species and study systems was dramatically reduced compared with traditional, directionally focused studies. This is contrary to a similar analysis that did not control for directionality of impacts, which found overall differences in impact depended on methodology. However, even when the effects of study ecosystem, invader life-form, and impact type were accounted for, significant differences occurred between removal and observational studies. Particularly vulnerable systems appear to be those that would be more greatly disturbed by the removal of the target species, such as tree species or invasive plants in riparian areas. Additionally, impact magnitude increased with invader cover and removal time. We confirm that invasive plants impact the systems they invade in a nonuniform manner; however, we suggest some study conditions may be more sensitive to study methodology. Careful consideration should be given as to which methodology is used in the context of the study system.

Biological soil crusts are associations of lichens, mosses, algae, cyanobacteria, microfungi and bacteria in different proportions forming a thin veneer within the top centimetres of soil surfaces. They occur in all biomes, but particularly in arid and semi-arid regions, even in the most extreme climates. They carry out crucial ecosystem functions, such as soil stabilization, influencing water and nutrient cycles, and contribute to the formation of microniches for heterotrophic life. In continental Antarctica especially, these roles are essential because no higher plants provide such ecosystem services. We provide a detailed description of biological soil crusts from Garwood Valley, McMurdo Dry Valleys region (78°S) and Diamond Hill (80°S) in the Darwin Mountains region. The coverage was low at 3.3% and 0.8% of the soil surface. At Garwood Valley the crusts were composed of green algal lichens, cyanobacteria, several species of green algae and the moss Hennediella heimii (Hedw.) R.H. Zander. Diamond Hill crusts appear to be unique in not having any species of cyanobacteria. Major parts are embedded in the soil, and their thickness correlates with higher chlorophyll contents, higher soil organic carbon and nitrogen, which are fundamental components of this species poor cold desert zone.

Total ecosystem carbon storage has frequently been found to increase with woody encroachment in savannas. However the loss of grass roots associated with woody encroachment can lead to a decrease in below-ground carbon storage which is not compensated for by an increase in above-ground carbon. To investigate how the extent of total woody cover affected ecosystem carbon, soil and above-ground carbon storage along eight thicket–savanna and five forest–grassland boundaries were measured. To investigate whether changes in soil carbon concentrations were related to the percentage of C4 (grass) roots to total roots and root quantity and quality, we measured fine-root biomass, root C : N ratios, root N, and % C4 roots at three different depths across thicket patches of different ages (n = 189). Forests contained significantly more carbon than adjacent grasslands in both above-ground carbon (mean difference 12.1 kg m−2) and in the top 100 cm of the soil (mean difference 4.54 kg m−2). Thickets contained significantly more above-ground carbon than adjacent savannas (3.33 kg m−2) but no significant differences in soil carbon were evident. Total fine-root biomass appeared to be more important than root quality (root C : N) in determining soil carbon concentrations during the encroachment process (i.e. in thicket of different ages). Similarly for thickets, the % C4 roots had no significant effect on soil carbon concentrations. In conclusion, thicket invading into open savanna vegetation did not lead to significant gains in ecosystem carbon at this study site. Significant gains were only evident in mature forest, suggesting that the process may take place very slowly.

The winter of 2009/2010 was particularly severe in Northern Portugal resulting in higher river flow levels. A study was undertaken to assess the impact of this situation on several populations of freshwater bivalves (e.g., Anodonta anatina, Corbicula fluminea, Margaritifera margaritifera, Potomida littoralis and Unio delphinus) in the catchments of the Rivers Minho, Douro, Tâmega, Tua and Sabor. Massive die-offs occurred for all species in all rivers, resulting in the removal of great numbers and biomass from the riverbed to the adjacent riverbanks, reaching maximum values of 2280 individuals.m−2 and 10 225 g wet weight.m−2, respectively. The invasive Asian clam C. fluminea had both highest density and biomass (however, this invasive bivalve is not dominant in several surveyed sites, and some rivers are still not colonized by this species). Results show that the quantitative and qualitative importance of this carrion transfer to the riverbank should be incorporated in future studies on the assessment of ecosystem function, contributing to a better understanding of the role of freshwater bivalves as resource pulses in adjacent terrestrial habitats. Some of the affected species have conservational importance and these extreme climatic events are predicted to increase in the future. These massive die-off events should be incorporated into management plans and selected restoration measures such as rapid relocation of endangered native mussels back to the riverbed can be easily applied to lessen possible impacts.

The Aegean Sea, due to the complexity and variety of morphological features, bathymetry, hydrological, hydrodynamic features and climatic characteristics, offers a unique opportunity for monitoring the spreading and/or invasion of alien biota. It is known that the establishment of warm/tropical marine alien species is related mainly to the increase in sea temperature. A significant increase in aliens' number along the southern Aegean (Dodecanese) coasts has been documented in the last twenty years, while their arrival has produced evident changes in coastal ecosystem composition and function. Although the study area acts as a crossroad for tropical alien species introduction in the eastern Mediterranean Sea, a direct attempt to link temperature alterations with new alien species arrivals has not been performed. Satellite and in situ derived marine temperature data showed that the study area has gone through a remarkable warming, while the link between global temperatures and regional ones revealed that this warming is not a local phenomenon but part of global climate trends. Examining relationships between new alien species arrivals data since 1929 against global temperatures, it is shown that their introduction rate parallels the significant increase of marine temperatures. The association of alien introductions with marine water warming, as well as potential effects on ecosystem functioning of selected species is discussed.

The Andean páramo ecosystems host geodiversity of global importance, but also have important societal functions, including agricultural production and delivery of water to people and industry. Páramo geo-ecosystems are highly susceptible to environmental degradation because of their alpine relief, extreme climate and fragile soils. In contrast to other parts of the world, geodiversity assessment studies in the Andes are scarce. A geodiversity assessment method was adapted and used to produce a potential geoconservation map of the Andean páramo. The Las Lagunas area (Cajamarca, Northern Peru) has a rich archive of climate proxy data and landscape reconstruction, and plays a key role in the functioning of regional geo-ecosystems. Undisturbed proxies for climate change are contained in four Late-Glacial recessional complexes of its former local ice cap and in pollen records preserved in the post-glacial peat cover. These new findings were used to develop a refined chronostratigraphy of the Late-Glacial warming period in the Andes of Northern Peru. Geo-ecosystem functions (for example water and carbon storage) depend on the environmental vulnerability and disturbance of the landforms and deposits. Therefore, potential geoconservation areas that combine a high scientific value and environmental vulnerability with a low disturbance and low frequency of occurrence should be prioritized for geoconservation. Such a strategy should also optimize sustainable use of resources and development of these areas. Mountainous countries like Peru require future management strategies that recognize and incorporate potential geoconservation information in regional planning, to prevent unnecessary loss of irreplaceable soils, climate proxies and geo-ecosystem functions upon future changes in land use and climate.