There are multiple paths via which environmental variation can impact herbivore ecology and this makes the identification of drivers challenging. Researchers have used diverse approaches to describe the association between environmental variation and ecology, including local weather, large-scale patterns of climate, and satellite imagery reflecting plant productivity and phenology. However, it is unclear to what extent it is possible to find a single measure that captures climatic effects over broad spatial scales. There may, in fact, be no a priori reason to expect populations of the same species living in different areas to respond in the same way to climate as their population may experience limiting factors at different times of the year, and the forms of regulation may differ among populations. Here, we examine whether the same environmental indices [seasonal Real Bioclimatic Index (RBI), seasonal Normalized Difference Vegetation Index (NDVI) and winter North Atlantic Oscillation (NAO)] influence body size in different populations of a large ungulate living in Mediterranean Spain, Western Scotland and Norway. We found substantial differences in the pattern of weight change over time in adult female red deer among study areas as well as different environmental drivers associated with variation in weight. The lack of general patterns for a given species at a continental scale suggest that detailed knowledge regarding the way climate affects local populations is often necessary to successfully predict climate impact. We caution against extrapolation of results from localized climate-population studies to broad spatial scales.

Iberian wild rabbit numbers have decreased in the last decades. The management implemented to recover rabbit populations includes several techniques, one of the most common being the construction of artificial rabbit warrens. To optimally distribute the artificial warrens in the field it is essential to understand natural warren microhabitat. Few studies have investigated the relationship between rabbits and grassland communities. In this work we study the spatial distribution and characteristics of rabbit warrens as well as their relation to grasslands in Mediterranean woodlands of central Spain. During the summer of 2001, three 12.5-ha study plots, including the most representative grassland communities of the area, were selected. All rabbit warrens were surveyed and the active and total entrances, shrub cover, grassland community and warren cover type were characterised. A grassland community selection index was calculated and the warren spatial distribution analysed. Ploughed lands and shallow soils were unsuitable for warren establishment. The mean number of burrow entrances per warren was 5.8 (4.4 active), and warren clustering occurred only in ploughed plots. However, pasture communities composed of annual and perennial species growing on unploughed deep sandy soils were preferentially selected. Most warrens (81.4%) were dug under some kind of protection such as shrub roots and rocks. According to our results, when designing rabbit restocking programs that include the provision of artificial warrens, unploughed deep soils with plenty of shrubs and rocks should be preferentially selected to locate the artificial warrens, which should be spaced so there are ~10 warrens per hectare and ~5–6 burrow entrances per warren.

Using the small-scale gradients in light and fertility imposed by the presence of trees on Mediterranean open oak woodlands, we studied differences in the ecology, floristic diversity and species composition of an annual grassland, and modeled plant relationships with soil properties and radiation using generalized linear models. The strong intra-annual variability in the annual grassland greatly affected overall floristic diversity estimates. Therefore, sampling at least twice during the annual growing period was important to avoid underestimating floristic composition. As has been found in previous studies, different groups of grasses were clearly shaped as a response to the ecological gradient created by the influence of the tree. However, when analyzing specific relationships, only a few individual species directly responded to the studied soil and light availability factors analyzed. Among them, those species considered 'ruderal' such as Carduus tenuiflorus, Echium plantagineum, Lolium rigidum, Rumex bucephalophorus, and Tolpis barbata showed a clear response to some nutrients and to light availability but displayed no relationship to N soil content. Our results suggest that individual species are responding to a combination of ecological factors. Therefore, some of the generally accepted assumptions regarding the ecology of specific taxa may not be as straightforward as traditionally considered.

In Spain, wild rabbits are essential for some highly endangered species, and, therefore, many actions have been undertaken to increase their populations. In the present study, artificial warrens are provided as a means to increase shelter for native wild rabbit populations in a given área. We evalúate the use of three types of warrens by rabbits and the effect on that use of five habitat characteristics at two spatial scales (500x500-m grids and 25-m plots). To evalúate that use, we identified pre-established signs at the entonces to each warren, and based on this, we calculated occupancy rate and activity. Our results indicate that rabbit abundance within a grid is the only variable which simultaneously explains both the greater occupancy and the higher activity in the artificial warrens located in that grid. Some 73.2% of the grids showed signs of rabbit use at the time of the evaluation. However, the pre-existing rabbit populations within the grids were not quantified and, henee, we cannot state that the warrens contributed to an increase in the rabbit abundance. Regarding the habitat, our results reveal that warrens should be situated in grids with food coverage of less than 50%, while the use of each individual refuge is greater where food availability in the immediate surroundings is at least 20% and shelter at least 50%). The tube warrens showed significantly greater rabbit use than the other types while there was little difference between the stone and pallet warrens in terms of use.

Agroforestry systems (mosaics of woodlands, rangelands and croplands) managed for red deer rearing and hunting constitute a profitable and increasing form of land usage in Mediterranean Spain since the 1960s. As a consequence, stocking rates have increased dramatically and are now frequently over 50 individuals/km2. That situation has created a new problem of sustainability for that new type of agroforestry systems. This paper analyses the selection of woody species by red deer and the effect of that species on Mediterranean shrublands at the Montes de Toledo range in central Spain. Selection indexes were measured for 33 woody species by comparing percentages of utilization (browsing) with percentages of availability. Phillyrea angustifolia, Arbutus unedo and Quercus faginea showed the highest selection indexes while Thymus mastichina, Daphne gnidium and Pinus pinea showed the lowests ones. Food preferences showed no significant variation with different red deer stocking rates. The effect of red deer stocking rates around 35 individuals/km2 on woodlands and shrublands seems to be over the sustainability level even though sown pastures and croplands are available for red deer populations within the study area.

Background: Soil fertility management and forest nutrition are key factors determining management and productivity of both natural and planted forests. Reference values for foliar and soil nutrient contents and assessment of nutrient balances to evaluate the sustainability of planted forest systems can guide forest managers in determining whether or not additional fertilisation is required.Methods: This review summarises the authors' research into the nutritional requirements for planted teak (Tectona grandis L.f.) forests in Central and South America. Teak is an important species for commercial forest plantations, usually in carefully selected productive sites, with rotations of 20-25 years and commercial volume anticipated to be around 10 m 3 ha -1 year -1 . Results: Foliar nutrient concentration values can be used as a reference to evaluate the nutritional status of planted teak forests. In addition, there may be an association between the dynamics of the concentrations of K, Mg and N with tree age and the age-related declines in teak productivity. Timber extraction by felling constitutes a major nutrient output from the system and repeated nutrient exports during several rotations could be a cause of soil nutrients depletion, especially P and K which typically have low availability in these Central American systems. Multivariate analyses have been shown to be appropriate and helpful tools for grouping forest stands by fertility classes (i.e. soil management zones using the terminology of precision agriculture). Conclusions: The techniques developed can be used as tools for the design of efficient fertilisation programmes, taking into account the inherent heterogeneity of soil fertility across different stands. This is considered as a first step towards a precision forestry scheme. Whether age-related changes in nutrient concentrations are a cause or a consequence of age-related declines in productivity is an important issue for future research.

Differences between Mediterranean European and other silvopastoral systems are described regarding both their human and natural environments. The long history of human utilization of the Mediterranean European environment has resulted in a close relationship between biodiversity, nature conservation and rational management, especially under the current European high socioeconomic situation. Therefore, silvopastoral methods should not be regarded as only productive activities but also, and mainly, as major conservation tools. Services (protection, stability, landscape, structural heterogeneity) and non-timber products (cork, fungus, fodder, fruits, honey) from the tree layer are usually much more important than timber products, including fuelwood, the demand for which has almost disappeared due to the availability of other sources of energy. Other consequences of the European high socioeconomic situation are the decrease of shepherding and transhumance, the partial substitution of extensive sheep herds by cattle and the excessive use of concentrate feed, which results in an unbalanced distribution of stocking levels and an uneven utilization of grazing and browsing resources. These changes result in local shrub encroachment, increased fire hazard and loss of biodiversity. Another major feature of European silvopastoral systems is the increasing hunting of big and small game as a new and very profitable type of wild livestock. Finally, a classification of Mediterranean European silvopastoral systems is presented, regarding the nature and distribution of their major components: tree or shrub layer, grass sward and animals.

Teak (Tectona grandis L.f.) is an important species in the worldwide quality tropical hardwood sector, which has gained significance in Central America since the first large plantations were established in the 1980s. The present work is a descriptive study that aims to: (1) analyse and characterise the general soil patterns which may be influencing teak plantations in Central America; (2) assess differences between countries and sub-regions; (3) create a global framework to help contextualise the soil fertility analyses conducted at sub-regional or farm level, and (4) determine the main problems associated with soil fertility in the region. Soil fertility was measured at 684 sites in Costa Rica, Guatemala and Panama. Although teak is considered to be a species with high soil nutrient requirements, and high fertility is usually assumed in teak plantations, the results show that this species has been planted in a wide variety of soils, including many with serious fertility problems (e.g. Ultisols and perhaps Oxisols) or with added difficulties due to their physical properties (e.g. Vertisols). The present analysis reveals a general K deficiency in the Central American teak plantations, where P deficiency and acidity toxicity are also relatively common problems. These soil fertility problems probably stem from poor site selection by forest managers in the 80s and 90s. Hence, although soil fertility is carefully evaluated when most teak plantations are established today, managers have to deal with soil fertility deficiencies in many sites where teak was established some years ago.