Functional traits related to regeneration responses to the environment are highly determinants of distribution patterns of plant communities. A large body of studies on seed traits suggests that regional climate may act as a strong filter of plant recruitment; however, few studies have evaluated the relative importance of seed traits and environmental filters for seed persistence at the population level. We tested the role of seed mass, water content and desiccation tolerance, as well as the germination time as proxies for seed tolerance to environmental filters (water deficit, heat shock and high temperatures) by comparing the response of tree species co-occurring in savannas located in different regions: Cerrado biome of Central Brazil and the Rio Branco savannas of northern Brazil. Seeds collected in savannas of Rio Branco showed a higher tolerance to environmental filters than those collected in savannas of the Cerrado. While the germination percentages largely varied in response to the treatments, the germination times were virtually unaffected by them, irrespective of seed origin, seed mass and water content. At the population level, the regional environment was a key determinant of seed tolerance to stress, irrespective of seed traits. Germination time was shown to represent a conservative seed trait and more linked to a species-specific germination strategy than to regional characteristics. Our results suggest that recruitment patterns of Cerrado savannas may be more impacted than Rio Branco savannas by the climate scenarios predicted for the future.

Se presentan los resultados del análisis de restos óseos y dentarios de micromamíferos (≤1 kg) recuperados en Vaquería Gruta 2 (VQG2), un sitio arqueológico localizado en el piedemonte alto de la precordillera de Mendoza (Argentina) con dataciones correspondientes al Holoceno tardío. Estos resultados se comparan con aquellos reportados para conjuntos óseos de micromamíferos cordilleranos del Centro-Occidente Argentino. Se realizó un análisis tafonómico para aproximarse a los posibles agentes acumuladores del conjunto óseo, sobre la base de abundancias relativas, patrones de fractura y digestión. Se analizaron variables orientadas a evaluar la actividad antrópica, tales como huellas de corte y termoalteraciones. Los resultados también se compararon con valores reportados en estudios tafonómicos actualísticos regionales para distintos depredadores. El análisis tafonómico permitió determinar que fueron aves rapaces los agentes responsables de la acumulación ósea recuperada en VQG2. Esta misma fue producto, probablemente, de una acumulación mixta. Asimismo, se realizó un análisis de la composición taxonómica de VQG2. Tanto la presencia de especies extirpadas en el registro arqueológico (Reithrodon auritus) como la mayor diversidad y equitatividad en dicho registro, en comparación con los ensambles actuales de micromamíferos, permiten pensar en un escenario de mayor heterogeneidad ambiental durante el Holoceno tardío, con mayor disponibilidad de parches de recursos que en el presente.

Does seed dormancy allow disturbance-oriented forest herbs such as Ageratina altissima to persist in heterogeneous natural communities? To document seed longevity and dormancy state, Ageratina seeds were buried in nylon mesh bags in second-growth forest stands in south-eastern Ohio, USA. Bags were recovered at 2-month intervals, and seeds were tested for viability and germinability in the lab. Live seed numbers declined rapidly, with seed banks exhausted in an estimated 33–37 months. Seeds showed a strong dormancy polymorphism, with 71–84% of live seeds germinable between March and July, the season of natural seedling emergence. At other dates, most seeds appeared to be in a state of induced dormancy, allowing little (0–21%) germination. The slope aspect of the burial site, an important factor controlling above-ground vegetation, had no effect on seed longevity or dormancy condition. Dormancy in Ageratina appears to be adapted to allow opportunistic germination in late spring–early summer, but to prevent germination in less benign periods. Seed longevity is shorter than the natural frequency of gaps in mesophytic forest. We conclude that a long-term dispersal/dormancy trade-off is probably an oversimplification of the spatial ecology of this species. The primary function of dormancy appears to be short-term tracking of seasonal variation.

Picoeukaryotes (<2–3 μm) perform key roles for the functioning of marine ecosystems, but little is known regarding the composition and diversity of picoeukaryotes in aquaculture areas. In this study, the Illumina MiSeq platform was used for sequencing the V4 variable region within the 18S rDNA gene to analyse genetic diversity and relative abundance of picoeukaryotic communities in the Qinhuangdao scallop cultivation area of the Bohai Sea. The community was dominated by three super groups, the alveolates (54%), stramenopiles (41%) and chlorophytes (3%), and three groups, dinoflagellates (54%), pelagomonadales (40%) and prasinophytes (3%). Furthermore, a contrasting station with open water away from the eutrophic aquaculture area was chosen. The communities collected from the two stations exhibited significant differences, with higher diversity in the aquaculture area. These results provide the first snapshot of the picoeukaryotic diversity in surface waters of the Qinhuangdao scallop cultivation area, and basic data for future studies on picoeukaryote community in an aquaculture region.

Whereas broad-scale Amazonian forest types have been shown to influence the structure of the communities of medium- to large-bodied vertebrates, their natural heterogeneity at smaller scale or within the terra firme forests remains poorly described and understood. Diversity indices of such communities and the relative abundance of the 21 most commonly observed species were compared from standardized line-transect data across 25 study sites distributed in undisturbed forests in French Guiana. We first assessed the relevance of a forest typology based on geomorphological landscapes to explain the observed heterogeneity. As previously found for tree beta-diversity patterns, this new typology proved to be a non-negligible factor underlying the beta diversity of the communities of medium- to large bodied vertebrates in French Guianan terra firme forests. Although the species studied are almost ubiquitous across the region, they exhibited habitat preferences through significant variation in abundance and in their association index with the different landscape types. As terra firme forests represent more than 90% of the Amazon basin, characterizing their heterogeneity – including faunal communities – is a major challenge in neotropical forest ecology.

Forest structure and species distribution patterns were examined among eight topographically defined habitats for the 205 species with stems ≥ 1 cm dbh inhabiting a 25-ha plot in the Sinharaja rain forest, Sri Lanka. The habitats were steep spurs, less-steep spurs, steep gullies and less-steep gullies, all at either lower or upper elevations. Mean stem density was significantly greater on the upper spurs than in the lower, less-steep gullies. Stem density was also higher on spurs than in gullies within each elevation category and in each upper-elevation habitat than in its corresponding lower-elevation habitat. Basal area varied less among habitats, but followed similar trends to stem density. Species richness and Fisher's alpha were lower in the upper-elevation habitats than in the lower-elevation habitats. These differences appeared to be related to the abundances of the dominant species. Of the 125 species subjected to torus-translation tests, 99 species (abundant and less abundant and those in different strata) showed at least one positive or negative association to one or more of the habitats. Species associations were relatively more frequent with the lower-elevation gullies. These and the previous findings on seedling ecophysiology, morphology and anatomy of some of the habitat specialists suggest that edaphic and hydrological variation related to topography, accompanied by canopy disturbances of varying intensity, type and extent along the catenal landscape, plays a major role in habitat partitioning in this forest.

Local species richness and between-site similarity in species composition of parasitoid wasps (Hymenoptera: Ichneumonidae; Pimplinae and Rhyssinae) were correlated with those of four plant groups (pteridophytes, Melastomataceae, Burseraceae and Arecaceae) in a western Amazonian lowland rain forest mosaic. The mosaic structure of the forest was related to variation in soils within the non-inundated terrain. Significant matrix correlation between patterns in parasitoid wasp species composition and plant species composition was found. Most of the overall correlation was due to idiobiont parasitoids of weakly concealed hosts, which attack host larvae and pupae in exposed situations, with two of the four ecologically defined parasitoid groups showing no correlation at all. A positive correlation between the number of plant species and the number of Pimplinae and Rhyssinae species at a site was found when the latter was corrected for collecting effort. Consequently, the degree of floristic difference between sites may be indicative of the difference in species composition of ichneumonids, and the species richness of plants may serve as a predictor of the species richness of parasitoid wasps. Although these results were obtained in a mosaic including structurally and floristically clearly different types of rain forest, the correlation coefficients were relatively low, and the present results lend only weak support to the idea of using plant distributions as indicators of animal distributions.

The oligarchy hypothesis proposes that large areas of Amazonian plant communities are dominated by limited sets of species. We tested this hypothesis by (1) quantifying dominance of the 10 most common species, genera and families in each region; and (2) assessing the consistency of relative abundance ranks between areas and across scales in dominance patterns for trees and lianas in two distant Amazonian regions (∼1900 km), the Yasuní and Madidi National Parks in Ecuador and Bolivia, respectively. The analyses were based on sixty-nine 0.1-ha plots in which all woody plants with a diameter at breast height (dbh) ≥2.5 cm were inventoried (19 775 individuals and 1729 species in total). The plots were located at two Yasuní and five Madidi sites, with an average of 10 plots per site. Overall, oligarchic dominance was pronounced at all the spatial scales investigated, although decreasing with increasing scale. Cross-scale relative abundance ranks were more consistent in Yasuní than in Madidi, while no such difference was apparent within single sites. Quantitative dominance and consistency of relative abundance ranks increased with taxonomic rank, being stronger at the family level than at genus and species levels. Species-level dominance was somewhat stronger within the 10 most common families in either region, than in other families. Dominance was similarly strong for canopy (dbh ≥10 cm) and understorey trees (dbh <10 cm), and less pronounced among lianas. In conclusion, our results provide strong evidence that western Amazonian forests can be dominated by limited oligarchies of species, genera and families over large expanses.

It has been known for a long time that fungi may transport substances in their hyphae. Experiments using radioactive tracer isotopes have greatly expanded our knowledge about translocation and have revealed that many fungi may circulate resources throughout their mycelia. This article outlines a conceptual framework for when and where net-translocation of resources takes place. Effects of substrate qualities, mycelial growth and activity as well as interactions with living plant hosts and other microorganisms are discussed and exemplified with experimental data. It is concluded that translocation from more or less remote parts of the mycelium enables fungi to colonise substrates with a low initial resource availability and to actively increase the resource availability in the substrates, turning the colonising mycelium from a resource sink into a source. Thus, translocation not only occurs in response to environmental heterogeneity, but also allows fungi to create heterogeneity in their growth environment.

The influence of environmental variables on epiphytic lichens in Liguria (NW Italy) was examined using two complementary approaches. Firstly, the variability of lichen vegetation in relation to environmental variables was investigated. Secondly, the variability of Lichen Biodiversity (LB) counts, used in biomonitoring studies, was analysed in relation to bioclimatic areas. Geomorphology strongly affects lichen vegetation. The coastal mountain ridge and the Tyrrhenian-Po valley watershed limit the distribution range of three different communities: a Parmelion community with a high frequency of coastal suboceanic species, a Parmelion community rich in oak wood species and the Pannelietum acetabuli association, situated beyond the Po Valley watershed. Substantial differences in the distribution of lichen communities related to a climatic gradient (from humid Mediterranean to dry sub-Mediterranean regions) are not matched by corresponding statistically significant differences in LB counts. More accurate studies are necessary to define homogeneous bioclimatic areas, in which LB values can be compared for biomonitoring purposes.