Cork Oak Forests Research Articles

Nutrient content and seasonal fluctuations in the leaf component of coark-oak (Quercus suber L.) litterfall

Nutrient content and seasonality of the leaf component in cork-oak litterfal were studied over a two year period in two cork-oak forest sites differing in biomass and edaphic condition in the north-eastern Iberian peninsula. Fallen senescent leaves compared to young leaves showed higher non-mobile nutrient concentrations and lower mobile nutrient concentrations, specially P, N, K, and Mg. At both sites, seasonal fluctuations affected both leaf production and leaf mineral content. The maximum leaf fall period correspond to the start of the vegetative growth and to the lowest N and P concentration in the falling leaves. The opposite was true for the winter, when litterfal was minimal and N and P content in falling leaves was at a maximum.

Predators ofLymantria dispar (Lep. lymantriidae) egg masses: Spatio-temporal variation of their impact during the 1988–89 pest generation in the mamora cork oak forest (Morocco)

In the Mamora cork oak forest (Morocco), oophagous predators of the gypsy mothLymantria dispar (L.) (Lepidoptera: Lymantriidae) are one of the main mortality factors influencing pest population dynamics. The predators destroy egg masses more by disrupting their cohesiveness than by predation. From 1987 to 1990, the impact of oophagous enemies significantly contributed to the collapse of a localized gypsy moth outbreak. Variation of egg mass dislocation intensity was greater between trees than among the different strata of a tree. The number of gypsy moth egg masses and egg predator attacks increased when oaks were large and unhealthy. Forest degradation probably explains why egg mass destruction rates were so high (60 to 90% of the eggs) in the infested forest. Oophagous predators find food and shelter under the dehiscent bark of unhealthy cork oaks.

The El Kala National Park and Environs, Algeria: An Ecological Evaluation

The structure of the El Kala National Park, its aims, zonation scheme for conservation and development, and boundaries, are described. Those ecobiomes and ecosystems which merit the highest classification and protection within the National Park are described and evaluated along with the numerous sites of similar importance outside the Park. A summary evaluation table (Table III) of the habitats, the species, and the resources for sustainable utilization, is presented.Three wetlands within the Park—Lake Oubeïra (perennial freshwater lake: a Ramsar Convention site important for wintering waterfowl), Lake Tonga (semi-perennial freshwater lake with surrounding marsh and earn a Ramsar Convention site with significant numbers of breeding waterbirds), and the Bou Redim marsh (freshwater carr with open water and a breeding colony of herons) are placed in the highest category of protection for the National Park. Four wetlands outside the National Park—the Mkhada marsh (8,900 ha of seasonally-flooded freshwater marsh), Lake Fetzara (15,000 ha freshwater lake now refilled with water in winter), Lac des Oiseaux (40 ha perennial freshwater lake), and the Cheffia Reservoir (3,000 ha)—are considered as important and consequently deserving of legislative protection. A marine section of the Park needs further study.The highest level of protection is recommended for the coastal dunes, including alder carrs, within and outside the Park; for the pristine low-montane Cork Oak woodlands, including the last remnants of Pinus pinaster ssp. renoui in Algeria; for the rare Lusitanian Oak forests including the small and declining Algerian population of Barbary Deer (Cervus elephas barbarus); and for some of the last remaining riverine woodland in North Africa. In addition, the healthy and diverse population of raptors is noted. The megalithic and later archaeological remains are extensive, valuable, and little-known.MEcological improvements to Lakes Tonga and Fetzara, which were drained in the 1930s, have recently developed from the operation of the old sluices to hold water back in the lakes, although at Lake Tonga some of the marginal vegetation and alder forest appears to be suffering from the prolonged inundation. The construction of the large Mexanna Dam within the National Park will desiccate the Mkhada Marsh, and Lake Oubeïra may have its ecological character changed if it is used for regulatory storage. The dune ecosystems are being affected by agriculture, groundwater pumping, industrial forestry (including perhaps a pulp mill), and the new road which is being driven into the heart of the dunes. Fishing and aquaculture may further reduce the suitability of Lakes Oubeïra and Melah for wintering waterfowl, and deliberate fires continue to ravage the Cork Oak forests.

Etude d'une infestation locale de la subéraie de la Mamora par le Bombyx disparate, Lymantria dispar (L.) (Lep. Lymantriidae), en 1987

It is admitted that the progradation of the Gypsy Moth in a cork oak forest starts with very localised outbreaks, called "sources". Such area (few ha) was located, and studied with focus on the space patterns within the Gypsy moth population. The data concerning the trees used (143 trees of Quercus suber L. on 4 ha), the egg masses and the indexes of parasites and predators damage were analysed using multivariate analysis and mapping. The only significant space pattern found was the gradient in egg masses numbers per tree. The trees phenology (spring bud break and fall of the old leaves) appears to vary randomly on tree to an another. The distribution of egg masses on trees and the distribution of entomophagous insects among the egg masses were remarkably homogenous and independant of the density gradient. These results show that a reduced sampling may be possible. Furthermore according to the results it can be supposed that all trees were infested at once by newly hatched caterpillars transported by wind from a primary source.

Contribution à l’étude des Collemboles des Maures (Var-France)

Inventory of collembolan fauna in some stations of cork oak and evergreen oak forests has been given. Fifty nine species have been recorded, six were new for this area. Some were particularly interesting : Anurophorus massoudi Poinsot endende of Maures mountains and Coloburella zangherii (Denis) known only from Pyrenean mountains, Abruzzes and from Eole island (Italy). These two former species occured in abundant populations and may be considered as the two characteristic species of this area.

Ecological fire influences on Quercus suber forest ecosystems

The effects of fire on the vegetation is one of the main factors in the present structure of Portugal’s landscape. Although caused exclusively through anthropogenic activities, the effects of fire have influenced the territory for so long that it can be considered as part of the natural evolutionary process. In the north, the highly fire-resistent deciduous oak forests were almost totally destroyed by man, they were consequently substituted by pine forests which in the last decades, due to increment of the understorey, have become a high-risk fire system. The effects of fire in the south of Portugal have produced a tree-steppe system, locally known as "montado”, a complex, multiple land-use system offering such activities as cereal production, game species habitats, and even recreation and tourism. Apart from substituting cork oak forest, the cork oak "montado" has also extended its distribution areas to formerly semi-evergreen forests. This may be attributed to the cork oak's strong fire resistence. The cork oak "montado" occupies approximately one quarter of Portugal's forest area where it presently constitutes one of the most productive multiple land use systems.

Contributo allo studio della vegetazione muscinale del territorio di Santo Pietro (Sicilia meridionale) : Sugherete, Leccete, Cisteti

Viene presentato uno studio brioecologico sulle formazioni boschive a Quercus ilex, Quercus suber e sulle garighe a Cistus sp.pl. del territorio di Santo Pietro (Sicilia meridionale) . Nella lecceta, data la notevole densità del bosco, si ritrova vai ricco contingente di specie sciafile della macchia alta e densa e delle foreste : Rhynchostegiella tenella var. litorea, Oxyrrhynchium praelongum var. stokesii, O. praelongum, Fissidens bryoides, F. bryoides ssp. incurvus, Brachythecium velutinum. Per contro, nella sughereta e nei cisteti, si nota da un lato un'accentuata diminuzione delle specie sopradette, dall'altro una netta predominanza di specie compagne degli stadi di degradazione delle foreste come : Trichostomum brachydontium, Weissia controversa, Scleropodium touretii, che mostrano una notevole plasticità, Pleuridium acuminatum, Fossombronia caespitiformis, entità xerofile, Timmiella anomala, T. barbuloides, Pleurochaete squarrosa, entità xerotermofile maggiormente diffuse nei cisteti in esame.

Spanish Refuge for Europe's Birds of Prey

In western Spain, especially in Extremadura, the typical Mediterranean flora and fauna are more abundant, both in species and numbers, than almost anywhere else in the Mediterranean region. For Europe’s birds of prey it is a key area. But all, especially the birds of prey, are gravely threatened, despite excellent protection laws, by reafforestation (with eucalyptus and pines) and industrial development destroying their habitats. The authors, who spent a total of ten months between 1970 and 1977 studying the birds of prey in the region, stress the urgent need to protect at least some of this superb country, which includes primeval cork oak forests and natural vegetation undisturbed by man.

The Cork Oak Forests and the Evolution of the Cork Industry in Southern Spain and Portugal

(1962). The Cork Oak Forests and the Evolution of the Cork Industry in Southern Spain and Portugal. Economic Geography: Vol. 38, No. 3, pp. 195-214.