Ecological Succession

The cockroach gut harbors a wide variety of microorganisms that, among other functions, collaborate in digestion and act as a barrier against pathogen colonization. Blattabacterium, a primary endosymbiont, lives in the fat body inside bacte-riocytes and plays an important role in nitrogen recycling. Little is known about the mode of acquisition of gut bacteria or their ecological succession throughout the insect life cycle. Here we report on the bacterial taxa isolated from different developmental instars of the cockroach Blattella germanica. The bacterial load in the gut increased two orders of magnitude from the first to the second nymphal stage, coinciding with the incorporation of the majority of bacterial taxa, but remained similar thereafter. Pyrose-quencing of the hypervariable regions V1–V3 of the 16S rRNA genes showed that the microbial composition differed signifi-cantly between adults and nymphs. Specifically, a succession was observed in which Fusobacterium accumulated w...

Although ecological succession is one of the principal focuses of recent restoration ecology research, it is still unclear which factors drive this process and positively influence species richness and functional diversity. In this study we sought to elucidate how species traits and functional diversity change during forest succession, and to identify important factors that determine the species in the observed assemblages. We analyzed species richness and functional diversity of ground beetle assemblages in relation to succession on post-industrial localities after habitat deterioration caused by spoil de-position. We selected ground beetles as they are known to be sensitive to landscape changes (with a large range of responses), and their taxonomy and ecology are generally well-known. Ground beetles were sampled on the spoil heaps during the last 30 years when spontaneous succession occurred. To calculate functional diversity, we used traits related to habitat and trophic niche, i.e. food specialization, wing morphology , trophic level, and bio-indication value. Ground beetle species were found to be distributed non-randomly in the assemblages in the late phase of succession. Ordination analyses revealed that the ground beetle assemblage was significantly associated with the proportion of forested area. Environmental heterogeneity generated assemblages that contained over-dispersed species traits. Our findings indicated that environmental conditions at late successional stages supported less mobile carnivorous species. Overall, we conclude that the decline in species richness and functional diversity in the middle of the studied succession gradient indicated that the assemblages of open habitats had been replaced by species typical of forest ecosystems.

During the Early Pleistocene, hominins dispersed from Africa to Eurasia via the Levant. The presence of African taxa in higher latitudes has been interpreted as indicative of an Africa savanna habitat in the Early Pleistocene of the Levant and as support for the hypothesis that the spread of grasslands into higher latitudes promoted the dispersal of hominins into Eurasia. To infer the paleoenvironment of the Levant during the Early Pleistocene, a multivariate analysis based on abundance and presence-absence data of mesoherbivores was used. Results indicate that in the Early Pleistocene, the Levant was situated in a Mediterranean woodland habitat. The presence of African taxa in novel environments may be explained using a long distance dispersal model and suggests that the spatial and temporal abundance pattern of African taxa in the Levant is consistent with the early stages of dispersal and is not indicative of the presence of savanna habitats in higher latitudes. The ecological success of hominins in higher latitudes as attested to by their widespread geographic distribution is consistent with their adaptation to novel environments and suggests that they may have been pre-adapted to variable environments.

The genus Castor comprises two species: the Eurasian beaver Castor fibre , and the North American beaver Castor canadensis . Both species suffered from overexploitation, but have seen a revival since the 1920s due to increased protection and reintroduction programmes. Increases in the populations and distributions of species that are able to modify ecosystems have generated much scientific interest. Here

We view Digital Ecosystems to be the digital counterparts of biological ecosystems. Here, we are concerned with the creation of these Digital Ecosystems, exploiting the self-organising properties of biological ecosystems to evolve high-level software applications. Therefore, we created the Digital Ecosystem, a novel optimisation technique inspired by biological ecosystems, where the optimisation works at two levels: a first optimisation, migration of agents which are distributed in a decentralised peer-to-peer network, operating continuously in time; this process feeds a second optimisation based on evolutionary computing that operates locally on single peers and is aimed at finding solutions to satisfy locally relevant constraints. The Digital Ecosystem was then measured experimentally through simulations, with measures originating from theoretical ecology, evaluating its likeness to biological ecosystems. This included its responsiveness to requests for applications from the user base, as a measure of the ecological succession (ecosystem maturity). Overall, we have advanced the understanding of Digital Ecosystems, creating Ecosystem-Oriented Architectures (EOA) where the word ecosystem is more than just a metaphor.

Landslides are excellent illustrations of the dynamic interplay of disturbance and succession. Restoration is difficult on landslide surfaces because of the high degree of spatial and temporal heterogeneity in soil stability and fertility. Principles derived from more than a century of study of ecological succession can guide efforts to reduce chronic surface soil erosion and restore both biodiversity and ecosystem function. Promotion of the recovery of self-sustaining communities on landslides is feasible by stabilization with native ground cover, applications of nutrient amendments, facilitation of dispersal to overcome establishment bottlenecks, emphasis on functionally redundant species and promotion of connectivity with the adjacent landscape. Arrested succession through resource dominance by a single species can be beneficial if that species also reduces persistent erosion, yet the tradeoff is often reduced biodiversity. Restoration efforts can be streamlined by using techniques that promote successional processes.

In northern Italy, on soil managed with three different tillage systems (conventional tillage, ridge tillage, and no-tillage) and submitted to standard cultural practices (crop rotation, and chemical weed control), the weed vegetation was assessed at the beginning of the trial (1987) and after six, and eight years. The aims were to evaluate (1) the effect of tillage systems on the weeds; and (2) the possibility of linking the floristic changes under reduced disturbance to the theory of ecological succession. The weeds were categorised according to life-forms (biological groups), periodicity types (ecophysiological groups), dispersal types and seed longevity. Data were analysed using Sørenson's Indices of Similarity, the Independence test, and Principal Components Analysis. The tillage systems profoundly altered the weed community: in undisturbed soils the importance of the geophyte and hemicryptophyte species, and among the annuals, Digitaria sanguinalis, Conyza canadensis and Kickxia elatine increased, as well as that of the wind-dispersed weeds. The species linked to disturbance were annuals and in particular Amaranthus spp., Chenopodium album and Echinochloa crus-galli. After eight years the floristic evolution in the reduced tillage system can be interpreted on the basis of ecological succession. The community that has formed assumes, from the quantitative point of view, characteristics of a pioneer community of secondary succession with a predominance of annual species and a large number of wind-dispersed plants. Qualitatively there is a movement towards a more mature community that could become similar to that of the woodland edge, with more perennial species, shrubs, and bird-dispersed plants. The implications of these conclusions are discussed in terms of weed management.

The option left by Art. 22 of the Regulation 650/2012 to the testator as to choosing the law applicable to the succession (lex hereditatis) strikes the balance between the law of the habitual residence and the law of nationality and has to be assessed as a positive development. Interpretation issues arise out of the provisions related to the choice of the law applicable to the succession, in particular when the choice is made by a mutual or a joint will or regarding the substantive validity or the form of the choice. In principle, the choice of the national law as applicable to the succession has an impact on international jurisdiction as it leads to the dissociation of forum and jus, because the court of the last habitual residence of the deceased seized upon the basis of Art 4 shall apply the law of the nationality of the deceased. However the dissociation can be dissipated and the correlation (or coincidence) of forum and jus reestablished (Art. 5-7), provided that the law chosen...

This work was carried out at Viçosa (20 º45'S, 42 º07'W) in the Southeastern region of Minas Gerais. The study examed the changes occurred in the stand between surveys done in 1984 and 1998. Species were then classified as pioneers, early secondary and late secondary. Changes in diametric distribution and absolute density were also investigated. Means were compared through student's t and square-chi (c2) tests. The stand showed to be constituted of nine pioneers, 56 early secondary, and 29 late secondary. Except for Plinia glomerata Berg.) Amshoff and Sorocea bonplandii (Daill.) Burger. Lanjow & Boer, no increase in absolute density could be detected for the individuals from the group of early secondary. The same trend was observed with in the pioneer species, without exceptions. These findings point out a tendency for decreasing importance of these ecological groups. Protium warmingianum March., the only late secondary to be analyzed, showed a significant increase in its absolute density. Overall, these facts suggested an improvement in the conditions of the area for the support of more advanced ecological groups in the successional scale.

Fire is an important disturbance that can impact biodiversity and ecosystem functions. Although fire impacts have been well studied in plants and some animals, the effects of fire on litter-dwelling arthropods remain poorly documented. I investigated the effect of time-since-burn on litter-dwelling arthropods in a Florida scrub ecosystem. I measured total arthropod richness and diversity as well as arachnid detritivore and predator abundance along a time-since-burn chronosequence. Arthropod richness and diversity and arachnid abundance significantly increased within 8 years post-burn. Arthropod richness and diversity and arachnid abundance did not differ between 8 and 89 years since last burn. These results demonstrate that litter-dwelling arthropods can quickly re-establish their community composition within 8 years after a burn, which may have important consequences for litter decomposition and nutrient cycling rates over successional time.

Insects are major components of forest ecosystems, representing most of the biological diversity and affecting virtually all processes and uses. In the USA, bark beetles (Coleoptera: Curculionidae, Scolytinae) heavily influence the structure and function of these ecosystems by regulating certain aspects of primary production, nutrient cycling, ecological succession and the size, distribution and abundance of forest trees. The purpose of

Fossil beetles from two last interglacial lake deposits from southern Wairarapa, central New Zealand are provisionally ascribed to marine oxygen isotope stages (MIS) 5a–e. Both assemblages represent ecological successions from lake margins to forest. The lower sample (MIS 5e) is characterized by species found today in northern New Zealand. These species, including Lorelus crassicornis, ‘Dasytes’ laticeps, Cryptobius nitidius, ‘Stenomalium’ sulcithorax, Psilocnaeia nana, and Microbrontes lineatus, represent a southward displacement from modern distributions by up to 700 km. Climate reconstruction indicates that temperatures at the time of deposition were 1.6–2.5°C warmer in the summer (January) and 2.3–3.2°C warmer in the winter (July) than at present. These results match local and regional pollen and phytolith findings of warmer, wetter conditions at the thermal maximum of the last interglaciation. In contrast, the upper sample is characterized by species that have widespread modern...