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Background and Aims Oaks are the foundation and dominant tree species of most Mediterranean forests. As climate models predict dramatic changes in the Mediterranean basin, a better understanding of the ecophysiology of seed persistence and germination in oaks could help define their regeneration niches. Tunisian oaks occupy distinct geographical areas, which differ in their rainfall and temperature regimes, and are thus a valuable model to investigate relationships between seed traits and species ecological requirements. Methods Seed morphological traits, desiccation sensitivity level, lethal freezing temperature, embryonic axis and cotyledon sugar and lipid composition, and seed and acorn germination rates at various constant temperatures were measured in Quercus canariensis, Q. coccifera, Q. ilex and Q. suber, using seeds sampled in 22 Tunisian woodlands. Key Results Only faint differences were observed for desiccation sensitivity in the oak species studied. By contrast, the species differed significantly in sensitivity to freezing, germination rates at low temperature and base temperature. Quercus ilex and Q. canariensis, which occur at high elevations where frost events are frequent, showed the lowest freezing sensitivity. A significant correlation was found between hexose contents in the embryonic axis and freezing tolerance. Significant interspecific differences in the time for seeds to germinate and the time for the radicle to pierce the pericarp were observed. The ratio of pericarp mass to acorn mass differed significantly among the species and was negatively correlated with the acorn germination rate. Quercus coccifera, which is frequent in warm and arid environments, showed the highest acorn germination rate and synchrony. Conclusions Seed lethal temperature, seed germination time at low temperatures, the ratio of pericarp mass to acorn mass and the embryonic axis hexose content appeared to be key functional traits that may influence the geographical ranges and ecological requirements of Mediterranean oaks in Tunisia.

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For the first time, the current study was designed to evaluate growing location on the chemical composition as well as the DPPH capacity of Crataegus azarolus L. (var. aronia (Willd.) Batt.) methanolic aqueous extracts. It was found that Crataegus azarolus L. collected from Neber (Governorate of Kef) had the highest total phenolic, flavonoids, condensed and hydrolysable tannin contents while the same genus growing in Jdidi (Governorate of Zaghouan) were characterized by the highest content of sugar (15.27 mg Gluc g −1 DW). Moreover, the plants contents' in P, K, and Na was investigated. Accordingly, the genus origins have shown to highly affect their content in the former minerals. In vitro, antioxidant activity was also determined using DPPH radical and expressed as concentration of each extract in order to inhibit 50% of DPPH radicals. The obtained values ranged from 55.22 to 138.66 μg mL −1 . From a nutritional and antioxidant point of view, Crataegus azarolus L. (var. aronia (Willd.) Batt.) can be considered as a valuable variety.

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The thuya (Tetraclinis articulata (Vahl.) Mast.) forests are one of the most important ecosystems in semiarid environments in north-western Africa, providing important economic profit and social services to local populations. However, lack of tools aiding sustainable management of these forests is detected. In the present work models for the main tree attributes as total height, crown diameter, height to crown base and stem form are developed for the species, using data from a net of plots installed in JbelLattrech region, in the NE Tunisia. Presented models allow characterizing the actual state and timber production of forests by using variables measured in typical forest inventories and conform a preliminary step for the future development of dynamic growth models.Key words: thuya; stem curve; semiarid environments; tree-level models. ResumenHacia el manejo sostenible de los bosques de araar (Tetraclinis articulata (Vahl.) Mast.) en Túnez: modelos para las principales variables de árbolLos bosques de araar (Tetraclinis articulata (Vahl.) Mast.) constituyen uno de los ecosistemas más importantes de los ambientes semiáridos del noroeste de África, siendo además fuente de importantes beneficios económicos y servicios sociales a las poblaciones rurales. Pese a este interés, hasta el momento no se han desarrollado herramientas que faciliten la gesitón sostenible de estas masas forestales. En el presente trabajo se presentan modelos para los principales atributos de árbol individual: altura total, diámetro de copa, altura hasta la base de la copa y ecuación de perfil, desarrollados para la especie a partir de datos obtenidos en una red de parcelas permanentes instalada en la región de JbelLattrech, en el NE de Túnez. Los modelos presentados permiten caracterizar el estado y producción maderera actual de los bosques de thuya a partir de las variables medidas habitualmente en los inventarios forestales para la gestión, y constituyen además un paso preliminar para el desarrollo futuro de modelos dinámicos de crecimiento para la especie. Palabras

Abstract. Farmland is a major land cover type in Europe and Africa and provides habitat for numerous species. The severe decline in farmland biodiversity of the last decades has been attributed to changes in farming practices, and organic and low-input farming are assumed to mitigate detrimental effects of agricultural intensification on biodiversity. Since the farm enterprise is the primary unit of agricultural decision making, management-related effects at the field scale need to be assessed at the farm level. Therefore, in this study, data were collected on habitat characteristics, vascular plant, earthworm, spider, and bee communities and on the corresponding agricultural management in 237 farms in 13 European and two African regions. In 15 environmental and agricultural homogeneous regions, 6-20 farms with the same farm type (e.g., arable crops, grassland, or specific permanent crops) were selected. If available, an equal number of organic and non-organic farms were randomly selected. Alternatively, farms were sampled along a gradient of management intensity. For all selected farms, the entire farmed area was mapped, which resulted in total in the mapping of 11 338 units attributed to 194 standardized habitat types, provided together with additional descriptors. On each farm, one site per available habitat type was randomly selected for species diversity investigations. Species were sampled on 2115 sites and identified to the species level by expert taxonomists. Species lists and abundance estimates are provided for each site and sampling date (one date for plants and earthworms, three dates for spiders and bees). In addition, farmers provided information about their management practices in face-to-face interviews following a standardized questionnaire. Farm management indicators for each farm are available (e.g., nitrogen input, pesticide applications, or energy input). Analyses revealed a positive effect of unproductive areas and a negative effect of intensive management on biodiversity. Communities of the four taxonomic groups strongly differed in their response to habitat characteristics, agricultural management, and regional circumstances. The data has potential for further insights into interactions of farmland biodiversity and agricultural management at site, farm, and regional scale.