Search results for "Biomas"

Experimental drought induces short-term changes in soil functionality and microbial community structure after fire in a Mediterranean shrubland

2014

Abstract. Fire is a major ecosystem driver, causing significant changes in soil nutrients and microbial community structure and functionality. Post-fire soil dynamics can vary depending on rainfall patterns, although variations in response to drought are poorly known. This is particularly important in areas with poor soils and limited rainfall, like arid and semiarid ones. Furthermore, climate change projections in many such areas anticipate reduced precipitation and longer drought, together with an increase in fire severity. The effects of experimental drought and fire were studied on soils in a Mediterranean Cistus-Erica shrubland in Central Spain. A replicated (n = 4) field experiment wa…

Assessing the biomass of shrubs typical of Mediterranean pre-forest communities

2012

One of the most outstanding issues of current environmental research is the need of reliable assessments of carbon stock (i.e. above-ground (a.g.) and below-ground biomass, deadwood, litter, and organic soil matter) within forest ecosystems. Although shrub vegetation plays an important role in accumulating carbon in many Mediterranean environments, there is still very little knowledge on the carbon they store. In this article, we analyze the a.g. carbon stock of several Mediterranean shrubby communities in Sicily (Italy), dominated by Pistacia lentiscus, Chamaerops humilis, Euphorbia dendroides and Spartium junceum. Plant samples for each species were selected, and morphometric attributes (…

Annual and monthly carbon balance in an intensively managed Mediterranean olive orchard

2013

At present, research activities on the role of orchard systems in sequestering atmospheric CO2 remain scarce. This paper aimed to contribute to assessing the carbon balance of a Mediterranean olive (Olea europea) orchard. The net ecosystem exchange, the ecosystem respiration and the gross primary production were computed for two consecutive years through eddy covariance, and the different biomass accumulation terms were also inferred in the same period through an inventorial method. The net carbon exchange ranged from 13. 45 t(C) ha-1 year-1 to 11. 60 t(C) ha-1 year-1. Very similar values [12. 2 and 11. 5 t(C) ha-1 year-1] were found with the direct carbon accumulation inventory. The intens…

A new lessepsian species in the western Mediterranean ( Brachidontes pharaonis Bivalvia: Mytilidae): density, resource allocation and biomass

2008

The present study reports on population dynamics and growth performance relative to a lesser known exotic invasive species ( Brachidontes pharaonis ) inhabiting the southern Mediterranean. The study was carried out in western Sicily, where B. pharaonis is present on both the submerged and emerged surfaces of a hyperhaline saltpan. Individuals were scraped, counted and measured for shell length, total weight, somatic, gonadic and shell biomass. Brachidontes pharaonis intensively colonized all hard substrates of the saltpan with annual average densities of 375 ± 293 ind. 400 cm −2 with density peaks in autumn as a function of habitat. The occurrence of juveniles was different for mediolittora…

Trying to link vegetation units with biomass data: the case study of Italian shrublands

2014

Although their carbon stock is relevant in assessing the baseline for the negotiation of future agreements with respect to carbon balance, there still are few available studies concerning the biomass and the net ecosystem exchange capacity of Mediterranean shrublands. In this chapter a preliminary overview on the biomass values concerning Italian shrubland communities and/or their dominant/ characteristic woody species is provided. Many useful data on above- and belowground biomass issued from investigations carried out in other Mediterranean countries and concerning plant communities, which share the same ecological, floristic and structural traits of Italian shrublands. A preliminary find…

Management of Mediterranean reforestations and the energetic use of the biomass: the case study of the Sicani Mountains (Western Sicily)

2015

Production and turnover of organic matter in three southern European Fagus sylvatica L

1999

Above-ground biomass, litterfall and litter accumulation and decomposition at the soil surface were studied within three Mediterranean beech forests from Italy, France and Spain in order to better understand the recycling of elements associated with the turnover organic matter Above-ground tree biomass amounted to 131.9 Mg ha-1 at Etna (Italy), 134.2 Mg ha-1 at Sierra de la Demanda (Spain) and 223.9 Mg ha-1 at Mont Lozère (France). The highest amount of total litterfall was observed at Sierra de la Demanda (4.7 Mg ha-1 year-1), followed by the Mont Lozère (4.4 Mg ha-1 year-1) and Etna (3.9 Mg ha-1 year-1). Total organic matter accumulated on the soil surface in the three beech forests amoun…

Spatial Distribution and Abundance of Mesopelagic Fish Biomass in the Mediterranean Sea

2020

Mesopelagic fish, being in the middle of the trophic web, are important key species for the marine environment; yet limited knowledge exists about their biology and abundance. This is particularly true in the Mediterranean Sea where no regional assessment is currently undertaken regarding their biomass and/or distribution. This study evaluates spatial and temporal patterns of mesopelagic fish biomass in the 1994–2011 period. We do that for the whole Mediterranean Sea using two well-established statistical models, the Generalized Additive Model (GAM) and Random Forest (RF). Results indicate that the bathymetry played an important role in the estimation of mesopelagic fish biomass and in its …

MARIOLA: a model for calculating the response of mediterranean bush ecosystem to climatic variations

1995

Abstract The paper summarizes the bush ecosystem model developed for assessing the effects of climatic change on the behaviour of mediterranean bushes assuming that temperature, humidity and rain-fall are the basic dimensions of the niche occupied by shrub species. In this context, changes in the monthly weather pattern serve only to outline the growth conditions due to the nonlinearity of response of shrubs to climatic factors. The plant-soil-atmosphere system is described by means of ordinary non-linear differential equations for the state variables: green biomass, woody biomass, the residues of green and woody biomasses, faecal detritus of mammals on the soil, and the total organic matte…

Post-fire soil functionality and microbial community structure in a Mediterranean shrubland subjected to experimental drought.

2016

Fire may cause significant alterations in soil properties. Post-fire soil dynamics can vary depending, among other factors, on rainfall patterns. However, little is known regarding variations in response to post-fire drought. This is relevant in arid and semiarid areas with poor soils, like much of the western Mediterranean. Furthermore, climate change projections in such areas anticipate reduced precipitation and longer annual drought periods, together with an increase in fire severity and frequency. This research evaluates the effects of experimental drought after fire on soil dynamics of a Cistus-Erica shrubland (Central Spain). A replicated (n = 4) field experiment was conducted in whic…