Low Shrubland Research Articles

Insight Into the Diversity of Flower‐Visiting Hoverflies (Diptera: Syrphidae) in Shrubland Maquis Around Ajaccio (South‐West Corsica, France)

ABSTRACTWith around 6000 species and 200 genera worldwide, hoverflies (Syrphidae, Diptera) are important and a diverse group of pollinators, second to wild bees (Hymenoptera). Here, we studied the diversity of Syrphidae visiting flowers in low shrubland maquis environments of three compensation areas in the Ajaccio region (Corsica, France). A total of 138 hoverflies visiting flowers were sampled representing 27 species from 16 genera. The subfamily Syrphinae was the most diverse in comparison to Milesinae or Eristalinae. The syrphid communities were dominated at 67% by seven species (Eumerus barbarus, Sphaerophoria scripta, Chrysotoxum intermedium, Episyrphus balteatus, Syritta pipiens, Melanostoma mellinum and Melanostoma scalare). Most of data reported here are new for the Ajaccio region. Loretto stands out from the other two sites with both a greater species diversity and specimen abundance of hoverflies recorded visiting flowers. With regard to the daily activity, flower visits by syprhids occurred mainly during the morning at the three studied sites, and flowers of Asteraceae were the most visited. Finally, hoverflies showed a marked seasonality since most records of flower visits occurred in autumn (from September to November) when other floral visitors are rarer or absent.

The effects of crop type, landscape composition and agroecological practices on biodiversity and ecosystem services in tropical smallholder farms

Abstract In the tropics, smallholder farming characterizes some of the world's most biodiverse landscapes. Agroecology as a pathway to sustainable agriculture has been proposed and implemented in sub‐Saharan Africa, but the effects of agricultural practices in smallholder agriculture on biodiversity and ecosystem services are understudied. Similarly, the contribution of different landscape elements, such as shrubland or grassland cover, on biodiversity and ecosystem services to fields remains unknown. We selected 24 villages situated in landscapes with varying shrubland and grassland cover in Malawi. In each village, we assessed biodiversity of eight taxa and ecosystem services in relation to crop type, shrubland and grassland cover and the number of agroecological pest and soil management practices on smallholder's fields of different crop types (bean monoculture, maize‐bean intercrop and maize monoculture). Increasing shrubland cover altered carabid and soil bacteria communities. Carabid abundance increased in maize but decreased in intercrop and bean fields with increasing shrubland cover. Carabid abundance and richness and wasp abundance increased with soil management practices. Carabid, spider and parasitoid abundances were higher in bean monocultures, but this was modulated by surrounding shrubland cover. Natural enemy abundances in beans were especially high in landscapes with little shrubland, possibly leading to lower bean damage in monocultures compared to intercropped fields, whereas maize monocultures had higher damage. In maize, grassland cover and pest management practices were positively related to damage. Carabid abundance was higher fields with high bean damage, and increased carabid richness in fields with high maize damage. Parasitoid abundance was negatively associated with bean damage. Synthesis and application. Our results suggest that maintaining biodiversity and ecosystem services on smallholder farms is not achievable with a ‘one size fits all’ approach but should instead be adapted to the landscape context and the priorities of smallholders. Shrubland is important to maintain carabid and soil bacterial diversity, but legume cultivation beneficial to natural enemies could complement pest management in landscapes with a low shrubland cover. An increased number of agroecological soil management practices can lead to improved pest control while the effectiveness of agroecological pest management practices needs to be re‐evaluated.

Dynamic vegetation cover and decline in common eider breeding numbers in Nova Scotia, Canada

The American common eider ( Somateria mollissima dresseri) is a colonially nesting sea duck breeding on islands in the coastal regions of Atlantic Canada. Declines in colony size have been pronounced in some parts of its range, notably in Nova Scotia, and may be attributable to a variety of interconnected factors including changes in habitat conditions. Using surveys collected two decades apart, we compared nesting habitat types, availability, and use by breeding eiders on 16 islands that supported >1600 eider nests in 1992–1993, but 830 nests in 2013. While general patterns of eider nesting habitat use remained consistent (e.g., nesting preferences exhibited for Low Shrubland and Grassland habitats, and avoidance of forest or beach habitats), overall vegetation cover declined, but relative habitat changes were inconsistent across islands. Three of the islands with the greatest change in vegetation had cormorant ( Phalacrocorax spp.) colonies in 2013 that were not there in the earlier years. We suggest that changes in vegetation, in some cases facilitated by cormorant colony formation, influenced susceptibility of nesting females to predators, and these interconnected factors may be contributing to local population declines.

Habitat preferences of Southern Ground-hornbills in the Kruger National Park: implications for future conservation measures

Understanding how a species utilises its habitat, and the processes that give rise to its movements and patterns of space use, is critical for its conservation. Southern Ground-hornbills Bucorvus leadbeateri are listed as Endangered in South Africa, as a result of habitat loss and persecution. The National Species Recovery Plan lists reintroductions as a suitable conservation action, but highlights “understanding the exact habitat requirements of Southern Ground-hornbills” as a knowledge gap. In this study, we used tracking data from six Southern Ground-hornbill groups (a total of 37,060 GPS locations) in the Kruger National Park to investigate their seasonal home range differences and habitat preferences. We used first-passage time analysis to determine the scale at which Southern Ground-hornbills concentrate their foraging efforts and whether specific movement behaviours were linked to habitat types. We found marked differences in seasonal home ranges, with all groups showing a range contraction during the breeding season. Grassland and open woodland habitat types were used throughout the year in accordance with their availability within the territory, with grassland, open woodland and dense thicket being favoured habitats for foraging. Our habitat preference results, based on longitudinal GPS data, allowed us to determine ideal habitat ratios (grassland:open woodland:low shrubland of 1.00:6.10:0.09 ha) to assist with the selection of suitable reintroduction sites for Southern Ground-hornbills. With an increasing number of species being threatened with extinction, reintroductions into suitable habitats may be a useful conservation mitigation measure. However, our findings highlight the importance of a thorough understanding of a species’ movement and space use prior to the selection of areas for reintroduction to ensure the establishment and sustainability of these species at these sites.

Vegetation recovery after fire in mountain grasslands of Argentina

Fire is a natural disturbance occurring every few years in many grasslands ecosystems. However, since European colonization, fire has been highly reduced or even suppressed in Argentinean grasslands, fostering ignitable material accumulation. This has led to occasional catastrophic control-demanding fire events, extended for larger areas. The aims of this work are to study vegetation recovery and change after a non-natural fire event in mountain grasslands. The study area is located in the Ventania mountain system, mid-eastern Argentina. We studied vegetation recovery after fire (January 2014) in two different communities: grass-steppes (grasslands) and shrub-steppes (open low shrublands). We measured vegetation cover, species richness and bare ground percentage in burned and unburned areas 1, 4, 8, 11 and 23 months after fire. Vegetation surveys were also performed at the end of the growing season (December) 11 and 23 months after fire. Data were analyzed using regression analysis, ANOVA and multivariate analysis (NMS, PERMANOVA). Both communities increased their vegetation cover at the same rate, without differences between burned and unburned areas after two years. Species richness was higher in shrublands and their recovery was also faster than in grasslands. Considering functional composition, besides transient changes during the first year after fire, there were no differences in abundance of different functional vegetation groups two years after fire. At the same time, shrublands showed no differences in species composition, while grasslands had a different species composition in burned and unburned plots. Also, burned grassland showed a higher species richness than unburned grassland. Data shown mountain vegetation in Pampas grassland is adapted to fire, recovering cover and richness rapidly after fire and thus reducing soil erosion risks. Vegetation in mountain Pampas seems to be well adapted to fire, but in grasslands species composition has changed due to fire. Nonetheless, these changes seem to be not permanent since pre-fire species are still present in the area.

Greenhouse Gas Emissions in Dairy Goat Farming Systems: Abatement Potential and Cost.

Simple SummaryAgriculture and particularly livestock farming is associated with the production of certain gases that contribute to global warming, commonly referred to as greenhouse gases. These gases are the result of the use of machinery and other inputs such as fertilizers and pesticides or are associated with the digestion process of animals. In this work, we have analyzed data from dairy goat farms in Greece to estimate the amount of greenhouse gases per kilogram of milk produced and identify farming practices that can result in their reduction. We found that greenhouse gases per kilogram of milk are fewer in farms that are characterized by higher milk production per goat. Furthermore, certain practices like the use of homegrown feed instead of purchased feed and the use of compound feedstuffs or oil-rich feedstuffs like cottonseed cake can result in lower greenhouse gases in goat farms. Also, the analysis suggests that the reduction of greenhouse gases can lead to a reduction of farm income, especially in the case of intensive farms. This finding has to be taken into consideration by policy makers and possible measures to compensate for this income loss have to be explored.Dairy goat farming is an important agricultural activity in the Mediterranean region. In Greece the activity offers occupation and income to thousands of families mainly located in mountainous and semi-mountainous areas of the country where it utilizes low productivity pastures and shrub lands. Furthermore, goats are more resilient to climate changes compared to other species, and are often characterized as ideal for keeping in drought areas. However, there is still limited evidence on total greenhouse gases (GHG) emitted from goat farms and their mitigation potential. In this context, this study aims to estimate GHG emissions of goat farms in Greece and explore their abatement options using an economic optimization model. Three case studies are explored i.e., an extensive, a semi-intensive and an intensive goat farm that correspond to the main goat production systems identified in Greece. The analysis aims to assess total GHGs as well as the impact of abatement on the structures, gross margins and labor inputs of the farms under investigation. The issue of the marginal abatement cost is also addressed. The results indicate that the extensive farm causes higher emissions/kg of milk produced (4.08 kg CO2-eq) compared to the semi-intensive and intensive farms (2.04 kg and 1.82 kg of CO2-equivelants, respectively). The results also emphasize the higher marginal abatement cost of the intensive farm. In all farm types, abatement is achieved primarily through the reduction of the livestock capital and secondarily by other appropriate farming practices, like substitution of purchased feed with homegrown feed.

New Information on Distribution and Habitat Preferences of the Leopard Skink, Lacertoides pardalis, across the Ultramafic Surfaces of Southern New Caledonia

New insights into distribution and habitat preferences of the large scincid lizard Lacertoides pardalis at a local scale were made during the course of a translocation study undertaken on the Kwe Range, in the region of the Plaine des Lacs of southern New Caledonia. Information gathered showed it to be distributed widely in elevation across the range where suitable habitat of outcropping rock was present, with a preference for rock habitat located within moderately low but dense maquis shrubland with a ground cover of tall sedges. Association with this particular stunted vegetative structure in part likely reflects the extent to which plant matter, primarily fruits of shrubs, constitutes a substantial component of the species' diet, as confirmed by scat analysis of captured individuals during the study. Lacertoides pardalis is currently recognized as “Vulnerable” under IUCN criteria, a designation assigned by virtue of its extremely limited area of extent and specialized biology. However, we here report a major extension in range, indicating that the species could be more widespread in suitable habitat across the whole of the southern ultramafic region of the island.

Long-term revegetation success of severely degraded chenopod shrublands

The restoration of severely degraded vegetation communities is often said to require mechanical intervention. However, the degree of intervention required, and its capacity to successfully restore areas of bare (scalded) soil and high weed cover into functioning chenopod shrubland, is unknown. Ten years on from mechanical intervention and direct seeding using a Contour Seeder and Camel Pitter, the abundance and cover of species was compared across disturbed and undisturbed microtopographic zones using one-way repeated-measures ANOVA and pairwise t-tests. Along Contour Seeder rip lines, recruitment of perennial species was greatest in the furrow (e.g. direct seeded: F2,78 = 27.15, P < 0.001; wild-sourced: F2,78 = 13.19, P < 0.001), and annual (and short-lived perennial) species equal to, or greater, on the undisturbed flat (wild-sourced: F2,98 = 43.91, P < 0.001). At the species-level, these trends often coincided with the species’ life-history strategy, but not always (e.g. the perennial Atriplex stipitata illustrated the annual trend; F2,78 = 7.71, P < 0.001). It is also important to note that a trend in recruitment could be driven by recruitment patterns in any one demographic phase. For example, the perennial trend in Atriplex vesicaria and Sida fibulifera abundance was driven by the recruitment of reproductive plants (F2,48 = 15.57, P < 0.001), or seedlings (F2,36 = 5.24, P = 0.010), respectively. These results indicate the functional benefits of mechanical intervention vary between species. The perennial and annual trends detected along Contour Seeder rip lines were less apparent along Camel Pitter rip lines where both perennial and annual species benefited from the initial disturbance. Overall, mechanical intervention facilitated the patchy recruitment of a Maireana pyramidata over A. vesicaria low shrubland, including several perennial and annual chenopods, indicating an early stage of recovery.

Den selection by barren-ground grizzly bears, Mackenzie Delta, Northwest Territories

Animals living in highly seasonal environments such as the Arctic must cope with periods of reduced resource availability. During periods of food shortage, some resident mammals hibernate and rely on energy stores to overwinter. To conserve energy, hibernating grizzly bears (Ursus arctos) excavate dens that provide thermal insulation and safety. To determine the distribution and habitat characteristics used by grizzly bears for denning in the Mackenzie Delta, Northwest Territories, Canada, we used kernel density and resource selection function analyses based on 624 den locations collected in 1972–2014. We found that grizzly bear dens were broadly distributed with varying densities over the landscape. Our analyses showed that bears selected den sites with aquatic bed and low shrub land cover, with soil types composed of sand- , gravel- , and glacier-deposited rock, and southeastern- , southwestern- , and northern-facing slopes. Grizzly bears also selected for areas with sloped terrain. Open spruce forest was avoided. Information on grizzly bear denning habitat could be used to inform human land use planning and minimize human–bear conflicts.

A phytosociological analysis of the Quercus coccifera L. stands in south Albania (NE Mediterranean)

Abstract The results of a phytosociological investigation of the Quercus coccifera L. stands occurring along the Adriatic and Ionian coasts in south Albania are given. The surveyed stands are localized in the Thermo-Mediterranean and Meso-Mediterranean belts. On the basis of literature and unpublished data, Q. coccifera stands extend from the shoreline up to 680 m of altitude, within the Quercetea ilicis vegetation zone. According to numerical analysis, Q. coccifera stands in south Albania can be divided into two broad groups forming macchia of 3–4 m height and low shrublands [0.5–1.5(-2) m)] defined primarily by degree of human pressure and altitudes. In addition, relevés from Q. coccifera stands in Albania were differentiated from Croatian and Montenegrin the Fraxino orni-Quercetum cocciferae associations. Conversely, Q. coccifera stands in south Albania share several biological and ecological similarities with those of the eastern Adriatic coast: hemicryptophytes prevailed and the chorological spectrum highlights a clear dominance of the steno-Mediterraneans. With respect to indicator values, an important differentiation from the eastern Adriatic associations was shown only in higher light intensity of the stands in Albania.

Management of Biodiversity in Australia

The concept of holistic ecosystem research, termed community-physiology, has gradually developed over the last 150 years. The discipline of community-physiology investigates the physico-chemical processes that determine the structure, growth and biodiversity of plant communities (with associated consumers and decomposers), both above and below ground, in space and time, from the tropical north to the temperate south of Australia. These physico-chemical processes (aerodynamic fluxes — frictional, thermal, evaporative ± atmospheric salinity — plus available soil water and soil nutrients) need to be clearly enunciated and integrated in ‘ecosystem models’ in order to predict the effect of perturbations (such as Global Warming, nutrient pollution, invasive biota, fire, overgrazing, etc.) on Australian ecosystems. An increase in global temperatures of 2 o C is predicted to affect the development of the foliage covers of overstorey and understorey strata resulting in open-forests —> woodlands —> open-woodlands —> tall shrublands —> low shrublands throughout Australia. In order to conserve Australian biota for posterity, community-physiologists, ecosystem modelers and environmental impact ecologists must have a deep understanding of the eco-physiology of producers, consumers and decomposers that compose an ecosystem and how these organisms interact with the continually-changing physico-chemical processes in the atmosphere and soil, in space and time.

Fisher–Shannon information plane analysis of SPOT/VEGETATION Normalized Difference Vegetation Index (NDVI) time series to characterize vegetation recovery after fire disturbance

The time dynamics of SPOT-VEGETATION Normalized Difference Vegetation Index (NDVI) time series are analyzed by using the statistical approach of the Fisher–Shannon (FS) information plane to assess and monitor vegetation recovery after fire disturbance. Fisher–Shannon information plane analysis allows us to gain insight into the complex structure of a time series to quantify its degree of organization and order. The analysis was carried out using 10-day Maximum Value Composites of NDVI (MVC-NDVI) with a 1km×1km spatial resolution. The investigation was performed on two test sites located in Galizia (North Spain) and Peloponnese (South Greece), selected for the vast fires which occurred during the summer of 2006 and 2007 and for their different vegetation covers made up mainly of low shrubland in Galizia test site and evergreen forest in Peloponnese. Time series of MVC-NDVI have been analyzed before and after the occurrence of the fire events. Results obtained for both the investigated areas clearly pointed out that the dynamics of the pixel time series before the occurrence of the fire is characterized by a larger degree of disorder and uncertainty; while the pixel time series after the occurrence of the fire are featured by a higher degree of organization and order. In particular, regarding the Peloponneso fire, such discrimination is more evident than in the Galizia fire. This suggests a clear possibility to discriminate the different post-fire behaviors and dynamics exhibited by the different vegetation covers.

Monitoring Vegetation Dynamics Inferred by Satellite Data Using the PhenoSat Tool

PhenoSat is an experimental software tool that produces phenological information from satellite vegetation index time series. The main characteristics and functionalities of the PhenoSat tool are presented, and its performance is compared against observed measures and other available software applications. A multiyear experiment was carried out for different vegetation types: vineyard, low shrublands, and seminatural meadows. Temporal satellite normalized difference vegetation index (NDVI) data provided by MODerate resolution Imaging Spectroradiometer and Satellite Pour l'Observation de la Terre VEGETATION were used to test the ability of the software in extracting vegetation dynamics information. Three important PhenoSat features were analyzed: extraction of the main growing season information, estimation of double growth season parameters, and the advantage of selecting a temporal region of interest. Seven noise reduction filters were applied: cubic smoothing splines, polynomial curve fitting, Fourier series, Gaussian models, piecewise logistic, Savitzky-Golay (SG), and a combination of the last two. The results showed that PhenoSat is a useful tool to extract NDVI metrics related to vegetation dynamics, obtaining high significant correlations between observed and estimated parameters for most of the phenological stages and vegetation types studied. Using the combination of SG and piecewise logistic to fit the NDVI time series, PhenoSat obtained correlations higher than 0.71, except for the seminatural meadow start of season. The selection of a temporal region of interest improved the fitting process, consequently providing more reliable phenological information.

Time-window of occurrence and vegetation cover preferences of Dartford and Sardinian Warblers after fire

Wildfires are the most extensive and severe disturbance affecting the shrublands where Sardinian and Dartford Warblers (Sylvia melanocephala and S. undata) abound. Estimating the long-term use of burned habitats by these species (i.e. their time-window of occurrence) is fundamental to understanding their regional distribution and to plan possible conservation measures for the near-threatened Dartford Warbler. In this study, we describe the post-fire time-window of occurrence and cover preferences of the two warblers using an abundance dataset, gathered by point counts over 22 consecutive years, and a density dataset, resulting from territory mapping of four different plots for up to 8 years. Both datasets span before and after fire. The two species colonized burned areas as soon as the second year after fire. The Dartford Warbler showed its highest abundance between 4 and 9 years after fire and disappeared after 16 years or more. The Sardinian Warbler had a peak of abundance at 9 years, but the study was not long enough to record its local extinction. Partial least squares regression showed that abundance at points and plot density of the Dartford Warbler were positively related to the plant cover between 0.25 and 1 m, whereas vegetation between 0.5 and 4 m was important for the Sardinian Warbler. The Dartford Warbler, therefore, depends on the existence of dense and low shrublands, that are often the result of past fires.

Projecting landscape changes in southern Chile: Simulation of human and natural processes driving land transformation

We describe a simulation model representing the most important human and natural factors driving land use and cover changes (LUCC) in southern Chile. We evaluate the model by examining its ability to simulate LUCC observed over the past three decades, conduct a sensitivity analysis of simulated trends to changes in important model parameters, and use the model to project likely landscape transformations over the next decade under “as usual,” “pessimistic,” and four “optimistic” scenarios. The model consists of five submodels representing LUCC on two distinct soil formations (volcanic ash and gleysols) and four major land use categories: native forest, agricultural land, shrubland, and urban land. Land use and cover sub-categories include old growth forests, secondary forests, and low and flooded shrubland. The model simulated well general historic trends in forest cover, agricultural land, shrubland, and urban land: from a forest-dominated landscape in 1976 to a landscape dominated by shrubland and agricultural land by 2007. Forest loss, forest degradation by logging and clearing for agriculture were the most important direct drivers of LUCC: forest logging and clearing were most important from 1976 to 1985, whereas after 1985 logging for firewood, driven by population growth, was most important. Sensitivity analysis indicated that model projections of general trends in the main land use and cover categories were not overly sensitive to changes in important model parameters, although further study is necessary to improve our estimates of the proportion of pasture requirements supplied by clearing low shrubland. Projections of LUCC suggested that a reduced amount of secondary forest would be left by 2017 if no actions are taken to reduce forest loss (“as usual”). Increasing population (“pessimistic scenario”) resulted in similar trajectories than those predicted by the as usual scenario, whereas reducing logging for firewood and increasing forest recruitment from shrubland could reduce loss of native forest by nearly one-third (“optimistic scenarios”). Surprisingly, shrubland exhibited the most complex and influential dynamics in all scenarios, being the immediate outcome of forest loss and the main long-term source of land for agriculture, urban expansion, and forest recovery. Few studies in Chile, or elsewhere, have considered the importance of this intermediate successional stage. Of the scenarios simulated, financial incentives targeted toward channeling shrubland into regenerated forest seemed most promising, although obstacles to such a management strategy exist.

Soil Seed Bank and Aboveground Vegetation in Grazing Lands of Southern Marmara, Turkey

The composition and conservation of plant communities is greatly influenced by the soil seed bank. Information on the soil seed banks and the remaining vegetation in these ecosystems is crucial for guiding the restoration efforts. This study examines the size, species richness, diversity, uniformity, and similarity of soil seed banks and aboveground vegetation in 6 different grazing lands including coastal pasture, reseeded pasture, artificial pasture, lowland shrubland, ungrazed pasture, and hillside shrubland. Forty-eight soil samples were taken by cores with a diameter and depth of 10 cm from each of grazing lands in August of 2007. A vegetation survey was conducted using a 0.5 x 0.5-m quadrant in both the spring and fall. Eighty species were observed in soil seed banks and aboveground vegetation. The largest seed bank was observed in reseeded pasture (7,715 seed/m2), while the smallest seed bank was found in coastal pasture (2,755 seed/m2). Coastal pasture also possessed the least amount of aboveground vegetation (131 plants/m2). The most aboveground vegetation was found in ungrazed pasture (155 plants/m2). The most common species in seed banks were annual and perennial grasses in reseeded pasture, annual forbs in artificial pasture and hillside shrubland, and perennial forbs in low shrubland and ungrazed pasture. Species richness, diversity, and uniformity in seed banks were highest in lowland shrubland and lowest in artificial pasture. The seed bank and aboveground vegetation were similar in ungrazed pasture, coastal pasture, reseeded pasture, low shrubland, hillside shrubland and artificial pasture. Shrublands play an important role in species richness and the number of germinated seeds from seed banks of grazing lands in southern Marmara. The results showed that reseeding or a decrease in grazing pressure may improve the condition of grazing lands.

The geographic and seasonal dimensions of habitat use in Galerida larks: implications for species coexistence and range limits

In this paper, we investigated the patterns of habitat use in three sibling species of larks: the Thekla lark Galerida theklae which is sympatric with either of two parapatric species of crested larks (G. macrorhyncha replacing G. cristata in arid areas of Morocco). Specifically, we addressed the following questions: 1) do species show niche conservatism in space (France vs Morocco) and time (breeding vs winter period)? 2) Does habitat use change at different interspecific densities? 3) Which factors drive the narrow range limit between G. cristata and G. macrorhyncha? We found that G. theklae was strongly associated with sloping and rocky (rugged) habitats in comparison with crested larks, but habitat use was not entirely consistent in space and time. Evidences for ecological displacement were mitigated. In the only habitat shared by G. cristata and G. theklae in France (vineyards surrounded by low shrubland), we observed a one‐third increase of G. theklae from nearby garrigues in winter, which coincided with a significant decrease of G. cristata after we controlled for density changes in non‐shared habitats. However, in Morocco, the use of rugged habitats by G. theklae was not affected by the prevalence of G. cristata or G. macrorhyncha in surrounding areas, at least at the spatial scales investigated. Our results suggest that interspecific competition plays a role in the parapatric distribution of G. cristata and G. macrorhyncha, because: 1) the alternative of a recent contact receives little support; 2) transition between species coincides with aridity gradients but not with topographic barriers or a sharp ecotone; 3) G. cristata also occurs in arid areas wherein G. macrorhyncha is rare or absent. Overall, our results add support to the view that a better integration of biotic interactions and spatio‐temporal variations in ecological niches might increase the predictive power of ecological niche models.

Production and Nutritional Quality of low elevation zone Grasslands and Kermes Oak Shrublands (Quercus coccifera L.) in the South-East Mediterranean Basin

Problem statement: The objective of this study was to evaluate the production and nutrition quality of grasslands and kermes oak shrublands in Preveza Prefecture, northwest Greece. Approach: The study involved the collection of herbage and browse samples along a grazing period, from March to October for two consecutive years. In consequence, browse samples were manually separated to leaves and twigs. The three forage components (herbage, kermes oak leaves and twigs) were analyzed for crude protein, Neutral-Detergent Fiber (NDF), Acid-Detergent Fiber (ADF), lignin and In Vitro Dry Matter Digestibility (IVDMD). After the 2 years of observation, we concluded that kermes oak browse, especially the leaves, had CP content adequate to fulfill the nutrient requirements of grazing goats throughout the grazing period. Results: However, this browse is characterized by a very low IVDMD during summer, which may be the result of high lignin content and the presence of anti-nutritional factors such as phenols and tannins. The month of harvest strongly affected the production and nutritive value of forage components, firstly by giving a significant positive correlation among average monthly temperature, production, cell wall contents and secondly, a negative correlation among average monthly rainfall, IVDMD and lignin content. Conclusion: In closure, kermes oak shrublands of the lower zone constitute an important alimentary source providing adequate amounts of browse in order to maintain the nutrient requirements for grazing goats during the summer, when the herbage is not desirable for consumption from sheep and cattle.

Microbial activities in soils of a Mediterranean ecosystem in different successional stages

This study reports a comparative analysis of soil enzyme activities (β-glucosidase, protease, urease, arylsulphatase, phosphatase and fluorescein diacetate hydrolase), ATP, total N and organic matter contents in three vegetal successional stages (meadow, low shrubland and high maquis) of a Mediterranean ecosystem in the Natural Reserve of Castel Volturno (Campania, Italy). Because water availability is a major limiting factor of soil microbial activity in Mediterranean ecosystems, the analysis was performed in late spring (May), after the rainy period, and in early autumn (October), after the long dry summer. A significant decrease in protease, arylsulphatase, urease and β-glucosidase activities was observed in meadow soil in the autumn sampling, probably due to the prolonged summer drought. Combining the values measured in the two sampling dates, the high maquis tended to have higher levels of enzymes activities than shrubland and meadow. Notably, high maquis had significantly higher phosphatase and arylsulphatase activities than shrubland and meadow and, in addition, a higher ATP content compared to meadow. Drastic changes were observed in EA/ATP ratios between the sampling periods in the meadow and shrubland, suggesting changes in the efficiency of microbial community more likely linked to climatic fluctuations than to the successional stage. The more stable EA/ATP ratio in the maquis probably reflects a constant contribution of microbial biomass to enzyme secretion. In conclusion, our results point to an increase in soil microbial activity accompanying the succession from meadow to high maquis that probably reflects a parallel increase in soil functions. Nevertheless, spatial heterogeneity and, more important, temporal variations in soil activities often may obscure differences related to the plant cover type.

Effects of fire on the vegetation of a lowland heathland in North-western Italy

This study focuses on the effect of fire on lowland heathlands at the extreme southern edge of their European distribution (Vauda Nature Reserve, NW Italy). Forty-nine plots (50 m radius) were surveyed between 1999 and 2006. Each year, fire occurrences were recorded and per cent cover of four vegetation types (grassland, heath, low shrubland, and tall shrubland) was estimated in each plot. Vascular plant species richness was also recorded in 255, 1 m2 quadrats. After a fire, grassland vegetation expanded, but then declined rapidly as heath and shrubland recovered: 7 years after a fire, tall shrubland encroached on to more than 40% of the plots, and grassland declined from 50% to 20% cover. Between 1999 and 2006, Betula pendula shrubland greatly expanded, while grassland decreased over most of the Reserve, even where fire frequency was high. Tall shrubland had low plant diversity and was dominated by widespread species of lower conservation value. By contrast, early successional vegetation (grassland and low shrubland) had higher richness and more narrowly distributed species, indication that the development of tall shrubland causes significant species loss in the heathland. Italian lowland heathlands are characterized by high rates of shrubland encroachment that threatens both habitat and species diversity. Burning frequencies of once in 3–6 years seem appropriate in this habitat, but burning alone might not suffice without actions to increase herbivore grazing.