. — Láng I.: 2005. A fenntartható agrárgazdaság és vidékfejlesztés. (Sustainable agriculture and rural development). MTA Társadalomkutató Központ. Budapest.
Greenland, D. J.— Szabolcs I. (Eds.): 1994. Soil Resilience
This study identifies the long lasting impacts of former cultivation on soils, seed banks and above-ground vegetation of limestone grasslands. We compared the resilience of three crop fields cultivated in the 19th century and abandoned (Abandoned Fields) with three grasslands which have never been cultivated (Old Grasslands). Grasslands were located in the Nature reserve of Grand-Pierre and Vitain valleys in France. Sites were identified using historical sources. Chemical and physical soil properties, above-ground vegetation and soil seed bank (0–10 cm and 10–20 cm) were studied. Data were analysed using a multivariate and univariate analyses to detect the effects/impacts of ancient cultivation. Our results clearly show that soil properties (e.g., calcium, carbonate, clay contents), above-ground vegetation (species diversity, moss and lichen cover) and seed bank (floristic composition, species-richness and diversity) are still impacted more than one century after their abandonment. Species richness of both above ground vegetation and seed bank are higher in old grasslands than in formerly cultivated fields. In the seed bank of the formerly cultivated soils we also found the presence of a very rare arable weed species (Althaea hirsuta) which has not been inventoried for a long time in the above-ground vegetation of the nature reserve. The resilience of formerly cultivated limestone grasslands might be influenced by the present management regime (site effect). Nevertheless, the resilience period of limestone grasslands is very long-more than one century-and return to an initial state might be difficult or impossible to reach.
Authors:C. Maucieri, C. Caruso, S. Bona, M. Borin, A. C. Barbera and V. Cavallaro
In many world regions, osmotic and salt stresses are becoming the primary environmental conditions limiting successful establishment of crops. The old durum wheat landraces may provide a source of genes useful to enhance crop resilience to the abiotic stresses of dryland areas or foreseen as a result of climate change. With this in mind, in order to determine the effects of salt and osmotic stresses on durum wheat germination, an old Sicilian durum wheat landrace “Timilia” and a relatively recent cultivar “Mongibello” were investigated at various iso-osmotic solutions of NaCl and mannitol at osmotic potentials of: 0 – control, –0.125, –0.250, –0.500 and –0.750 MPa.
Under stress conditions, different germination and early growth behavior was observed in the two durum wheat genotypes. Timilia presented almost stable germination even at the highest osmotic stresses (96.7% and 88.3% seed germination at 0 and –0.750 MPa, respectively) showing a higher capacity of seed imbibition than Mongibello. The latter thus showed a higher sensitivity than the old landrace to the studied stresses. The variability ascertained in the response to salinity stress indicate that Timilia could be a source of interesting genes for breeding programs.
Authors:S. Ongaro, S. Martellos, G. Bacaro, A. De Agostini, A. Cogoni and P. Cortis
The Mediterranean is one of the major biodiversity hotspots of the world. It has been identified as the “core” of the speciation process for many groups of organisms. It hosts an impressive number of species, many of which are classified as endangered taxa. Climate change in such a diverse context could heavily influence community composition, reducing ecosystems resistance and resilience. This study aims at depicting the distribution of nine orchid species in the island of Sardinia (Italy), and at forecasting their future distribution in consequence of climate change. The models were produced by following an “ensemble” approach. We analysed present and future (2070) niche for the nine species, using Land Use and Soil Type, as well as 8 bioclimatic variables as predictors, selected because of their influence on the fitness of these orchids. Climate change in the next years, at Mediterranean latitudes, is predicted to results mainly in an increase of temperature and a decrease of precipitation. In 2070, the general trend for almost all modelled taxa is the widening of the suitable areas. However, not always the newly gained areas have high probability of presence. A correct interpretation of environmental changes is needed for developing effective conservation strategies.
Authors:R. A. Correia, A. M. A. Franco and J. M. Palmeirim
The Mediterranean Sea has separated the sclerophyllous forests of southern Europe and northern Africa for millions of years, but its role structuring forest bird assemblages remains unclear. To address this issue we sampled bird assemblages in cork oak woodlands located north and south of the Strait of Gibraltar and compared abundance, diversity, and species and guild assemblage structure between regions. Abundance and diversity patterns were remarkably similar, but dissimilarity analyses of species and guild composition revealed differences in bird assemblage structure between regions. Differences are partly attributable to the effect of the Mediterranean as barrier to the dispersal of forest birds; a few species were unable to colonize North Africa, and many that colonized it remained in sufficient isolation to evolve into distinct taxa. In addition to this divergence of biogeographic genesis, assemblages also differ because in North African cork oak woodlands forest and insectivorous specialist species are less abundant. This dissimilarity could be due to the effect of different exploitation levels present in each region. Managed cork oak woodlands are widespread in the Western Mediterranean, and are valuable because they conciliate economic exploitation with high biodiversity. In North Africa these woodlands are of greater conservation concern because they harbour endemic bird species that give its assemblage a distinct character, cover a smaller area, and are currently under greater pressure from overexploitation. These results highlight the importance to implement management practices that increase resilience and maintain biodiversity value throughout the range of cork oak woodlands.
Authors:J. Wang, L. Huang, H. Ren, Z. Sun and Q. Guo
Soil seed banks can act as an important source in forest regeneration, and the information on the seed bank composition is vital for determining the resilience of plant communities under severe environments such as urban settings. In this study, we examined the seed bank density and functional composition, and their relationships with aboveground vegetation in three remnant evergreen broad-leaved forests, i.e., PuGang (PG), LuoGang (LG), and DaLingShan (DLS) under urbanization in Guangzhou, South China. In both years of our study (2010–2011), seed density and species richness for overall soil seed banks and each classified life forms (tree, shrub, herb and grass) significantly differed among the forests and were much higher in the PG forest. The prevailing life forms in the seed banks were herbs and grasses, and the proportion of tree species Importance Value index (IV) of the seed banks was low. We did not detect significant difference in the percentage of exotic species seeds in the seed banks among the forests. The proportion of species with animal dispersal mode was much higher in the DLS forest than in the PG and LG forests. The similarity in species composition between standing vegetation and seed banks was low with the lower value in the DLS forest than in PG and LG forest. Our findings suggest that the regeneration potential of the soil seed banks is limited for the remnant forests in urban areas. Therefore, greater proactive and enhanced conservation efforts are thus needed.
Authors:F.A. Rodríguez-Zaragoza, M. Ortiz, F. Berrios, L. Campos, A. de Jesús-Navarrete, J. Castro-Pérez, A. Hernández-Flores, M. García-Rivas, F. Fonseca-Peralta and E. Gallegos-Aguilar
Banco Chinchorro is the largest reef in the Mexican Caribbean. Historically, spiny lobster, queen conch and over 20 other reef species have been exploited here. Multispecies intervention management from an ecosystem perspective has been developed in this area; however, an assessment of the effects of such practices on ecosystem health is required. Five quantitative trophic models were constructed using Ecopath with Ecosim. The results show that, in terms of biomass, benthic autotrophs are the dominant group in all communities. Ecosystem Network Analysis indices showed that Cueva de Tiburones was the most mature, developed, complex and healthy subsystem, but, El Colorado and La Baliza were the subsystems most resistant to disturbances. The fisheries mainly concentrate on primary (La Baliza and Cueva de Tiburones sites) and secondary consumers (La Caldera, Chancay, and El Colorado). The greatest propagation of direct and indirect effects, estimated by Mixed Trophic Impacts and Ecosim simulations, were generated by the benthic autotrophs, small benthic epifauna, benthic-pelagic carnivorous fish and benthic carnivorous fish, among others. In contrast, the System Recovery Time showed different patterns among subsystems, indicating several compartments that reduce resilience. Considering the structure, dynamics, trophic functioning and ecosystem health of Banco Chinchorro, its ecological heterogeneity highlights the need for the design of a specific (by subsystem) management strategy, particularly because different species or functional groups present greater sensitivity to human interventions in each community.