Vertical Divergence of Cultured Microfungal Communities at the Hallamish Dune Field,Western Negev Desert,Israel

We examined the depthwise distribution of microfungi through 0–40 cm of sandy profiles under bare surface and different shrub species at the Nizzana research site (NRS) in the Negev Desert, Israel. A total of 125 species from 61 genera were isolated using the soil dilution plate method. At the topsoil of all profiles melanin-containing species with large multicellular conidia predominated. In the middle depths at the majority of the profiles, mesic group of microfungi, Penicillium spp. substantially increased in abundance. Density of microfungal isolates decreased with depth under shrubs and did not substantially vary in the nonshaded profiles, highly positively correlating with electrical conductivity and organic matter (OM) content. Substantial increase in isolate densities at the undercanopy habitats, especially in the interdune depression with higher substrate stability raising the accumulation of OM, highlights the role of shrubs as “islands of fertility” for microfungal communities at NRS.     

Adaptive spatiotemporal distribution of soil microfungi in 'Evolution Canyon' III, Nahal Shaharut, extreme southern Negev Desert, Israel

We examined adaptive spatiotemporal mycobiota structure in the soil of 'Evolution Canyon' III, Nahal Shaharut, in the extreme southern Negev, Israel. A total of 223 species representing 80 genera were isolated using the soil dilution plate method. The microfungal communities in all localities and seasons were characterized by a superdominance of dark-coloured species with large multicelled conidia:  Ulocladium atrum, U. botrytis, Alternaria alternata, and Al. chlamydospora . Species of the genus Aspergillus (mainly As. fumigatus ) and teleomorphic ascomycetes comprised a basic part of the thermotolerant mycobiota obtained at a temperature of 37 °C. Isolate density displayed high positive dependence on organic matter content. Density was subject to drastic spatiotemporal (especially spatial) fluctuations, with maximum levels found in the shady valley bottom locality. The lowest biodiversity indices were estimated in localities under shrubs and in the most stressful summer and spring. The results demonstrated a clear effect of harsh desert climatic and edaphic selection on the adaptive variation of the mycobiota studied.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 90 , 263–277.     

Soil microfungal communities of 'Evolution Canyons' in Israel – extreme differences on a regional scale

On a regional scale, we compared the local adaptive patterns of soil mycobiota revealed in four 'Evolution Canyons' located in the northern and southern parts of Israel. These microsites were chosen according to the framework of the Institute of Evolution, University of Haifa programme, focusing on the effect of interslope environmental divergence on biodiversity patterns. The comparative analysis demonstrated remarkable differences in spatiotemporal structure of the microfungal communities and their biodiversity level (species richness, heterogeneity and equitability). In the desert 'Evolution Canyon', stress-selected, slow-reproducing, dark-coloured species with large, multicelled conidia were dominant. At the same time, in the forest localities of the northern canyons, as well as in the agriculturally disturbed locality with soil degradation, ruderal-selected, fast-reproducing Penicillium species predominated. Environmental natural selection appeared to be the major factor affecting adaptive diversity patterns of soil microfungi in the studied area.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 157–163.     

Feeding,energy flow and soil turnover in the desert isopod,Hemilepistus reaumuri

The desert woodlouse Hemilepistus reaumuri is one of the most abundant macroscopic invertebrates in North Africa, the Arabian steppes, semi-desert and desert, and the Negev desert Israel.The main purposes of our study were:     

Acidification of sandy grasslands – consequences for plant diversity

Questions: (1) Does soil acidification in calcareous sandy grasslands lead to loss of plant diversity? (2) What is the relationship between the soil content of lime and the plant availability of mineral nitrogen (N) and phosphorus (P) in sandy grasslands? Location: Sandy glaciofluvial deposits in south‐eastern Sweden covered by xeric sand calcareous grasslands (EU habitat directive 6120). Methods: Soil and vegetation were investigated in most of the xeric sand calcareous grasslands in the Scania region (136 sample plots distributed over four or five major areas and about 25 different sites). Environmental variables were recorded at each plot, and soil samples were analysed for exchangeable P and N, as well as limestone content and pH. Data were analysed with regression analysis and canonical correspondence analysis. Results: Plant species richness was highest on weakly acid to slightly alkaline soil; a number of nationally red‐listed species showed a similar pattern. Plant species diversity and number of red‐listed species increased with slope. Where the topsoil had been acidified, limestone was rarely present above a depth of 30 cm. The presence of limestone restricts the availability of soil P, placing a major constraint on primary productivity in sandy soils. Conclusions: Acidification of sandy grasslands leads to reduced abundance of desirable species, although the overall effect is rather weak between pH 5 and pH 9. Slopes are important for high diversity in sandy grasslands. Calcareous soils cannot be restored through shallow ploughing, but deep perturbation could increase the limestone content of the topsoil and favour of target species.     

Seasonal abundance patterns of the sandfly Phlebotomus papatasi in climatically distinct foci of cutaneous leishmaniasis in Israeli deserts

Among foci of cutaneous leishmaniasis in Israel, population densities of the vector sandfly Phlebotomus papatasi Scopoli (Diptera: Psychodidae) were assessed during April-October 1999 in the mesic Negev desert and the hyper-xeric Arava valley, using sticky traps placed overnight near host burrows of the fat sand rat, Psammomys obesus Cretzschmar (Cricetidae: Gerbillinae). Population dynamics of Ph. papatasi differed between the Negev (study sites on sand near Mount Keren and on loess at Nizzana ruins) and the Arava valley (study sites on sand at Shezaf and in a fallow field near irrigation at wadi Arava). At the Negev sites, sandfly abundance peaked in spring (April or May), whereas at Arava sites Ph. papatasi population densities were bi-modal, with peaks in both spring and autumn (September or October). This might be conducive to sustaining enzootic Leishmania major Yakimoff & Schokhor (Kinetoplastida: Trypanosomatidae). In both areas, Ph. papatasi densities were much higher at the site with moister soil, raising transmission risks of zoonotic cutaneous leishmaniasis.     

Microsatellite markers for assessing DNA polymorphism of Emericella nidulans in nature

Based on genome sequence of Emericella nidulans, primers for 25 microsatellites were designed, of which, seven were chosen as polymorphic markers (five to 12 alleles). Simple sequence repeat (SSR) polymorphism was tested in 44 isolates from extremely arid soils of the southern Negev desert, Israel and some related species of Aspergillus. The SSR marker set appears suitable for population studies in diverse ecological conditions.     

Influence of wildfire on diversity of culturable soil microfungal communities in the Mount Carmel forest,Israel

The fire-related variations in culturable microfungal communities in the soil of the Mount Carmel forest, Israel, were examined by comparing the communities from burned and adjacent unburned soil plots under pine and oak trees – collected 6, 18, and 26 months after the fire. A total of 82 species representing 44 genera were isolated using the soil dilution plate method. The results showed that the fire had strongly influenced the composition and structure of microfungal communities. The fire remarkably changed physical and chemical properties of the environment, decreasing water holding capacity, organic matter and total nitrogen content in the burned soil. These changes supported abundant development of fast-growing mycoparasitic species (Clonostachys rosea and Trichoderma spp.) and caused significant decrease in species richness. The variations in community composition were much more expressed in the burned soils under oak vegetation as compared with the pine trees. In the oak burned soils, the contribution of the “mesic” component, Penicillium spp., was markedly lower, whereas the contribution of the “xeric”, stress-selected component, melanin-containing species, was higher than in the unburned communities. Such variations can be also considered as a community response to the fire-related decrease in water and nutrient content in the burned soils.     

Two ITS forms co-inhabiting a single genet of an isolate of Terfezia boudieri (Ascomycotina), a desert truffle

Two fruit-bodies of Terfezia boudieri Chatin, each exhibiting a mixture of two ITS -RFLP profiles, were found in the Negev desert of Israel. A mycelial culture obtained from glebal out-growth maintained the double profile, as did proliferating cultures established using single hyphae isolated from the original cultures. The main difference between the two ITS variants lies in a 21 bp deletion in the smaller variant. The question whether both variants are contained within a single nucleus or occupy different nuclei sharing the same cytoplasm is discussed.     

Estimating hydraulic conductivity of a sandy soil under different plant covers using minidisk infiltrometer and a dye tracer experiment

The objective of this study was to estimate the hydraulic conductivity of sandy soil under different plant cover at the locality Mláky II at Sekule (southwest Slovakia). Two sites were demarcated at the locality, with mainly moss species at glade site, and pine forest at forest site. The estimation of unsaturated hydraulic conductivity was conducted by (a) minidisk infiltrometer and (b) the analysis of a dye tracer total resident concentration. The latter approach assumed the applicability of the stochastic—convective flow theory in the sandy soil. In the dye tracer experiment, two plots (1 × 1 m each) were established in both sites, and 100 mm of dye tracer (Brilliant Blue FCF) solution was applied on the soil surface. Similar results were obtained in both plots, with more than 70 % area of horizons stained in the depth of 30–50 cm. In some cases, the predicted and measured hydraulic conductivity were found within an order of magnitude, thus revealing similar impact of different plant cover on hydraulic properties of sandy soil studied. In contrast to sandy soils used for agriculture, the influence of the plant/surface humus and topsoil interface extended in the form of a highly heterogeneous matrix flow to the depth of 50–60 cm, where it was dampened by horizontal layering.     

Vegetation patterns,microtopography, and soils on a Chihuahuan desert playa

Abstract. Spatial patterns of vegetation on an ephemeral lake bed (playa) in the northern Chihuahuan desert were closely correlated with elevation. Distributions of species along a 265 m transect from the center to the edge of the playa showed abrupt boundaries at 110 m and 220 m. These boundaries seem related to the maximum elevation covered with standing water following complete flooding, and to an edaphic boundary between heavy clay soils at the center of the playa and adjacent soils. The complete turnover in species composition across this transect, with an elevation change of only 85 cm, indicates that environmental gradients resulting from flooding and soil development are steep. Vegetative patterns within the lowest part of the playa were patchy, with patch diameters ranging from 2 to 5 m. These patches appear to be produced by differences in the duration and frequency of flooding between small knolls and depressions resulting from gilgai microtopography.     

Biodiversity and microclimatic divergence of chrysomelid beetles at 'Evolution Canyon', Lower Nahal Oren, Mt Carmel, Israel

Ninety species of leaf beetles (Chrysomelidae, Coleoptera, Insecta) were recorded from die 'Evolution Canyon' microsite (sample area 7000 m²), Lower Nahal Oren, Mt Carmel, Israel. Species richness was significandy ( P =0.018) higher on the drier, climatically more fluctuating savanna-like, soudi-facing slope (SFS, 60 species, sample area 3000 m²) than on the cooler, wetter and climatically less variable north-facing slope (NFS, 44 species, sample area 3000 m²), as in other terrestrial taxa. More species were found common to the local xeric SFS at die Canyon and the regional southern desert areas (Judean and Negev Deserts), than to the NFS and Galilee Mountains, respectively, suggesting that local patterns mirror regional patterns. Interslope differences in microclimate variability range indicate that this factor might be determinant of interslope species richness differences. Most species were collected in the spring (April; 47%) and least in the autumn (September; 3%) over the collecting period from March 1995 to June 1997.     

Vegetation-environment relationships in a Negev Desert erosion cirque

The relationship of desert vegetation to topographic and edaphic factors in Makhtesh Ramon, an erosional cirque in the Negev Desert of Israel, was analyzed using redundancy analysis ordination. Altitude and geological substrate had the most significant correlations with vegetation patterns. In particular, significant and monotonic increases in both total species richness and the percentage of annual species were found with increasing altitude. A comparison was made of the effectiveness of Whittaker's diversity sampling plots (Shmida 1984) versus the log-series survey method of McAuliffe (1990). We concluded that at small sample sizes, the Mc Auliffe plots were more likely to yield interpretable ordination results, even though they included only the perennial flora.     

Nest predation and nestling growth rate of two lark species in the Negev Desert, Israel

Clutch-size, nestling growth and predation rates on eggs and nestlings in two sympatric alaudids, the Crested Lark Galerida cristata and the Desert Lark Ammomanes deserti, were studied in the Negev desert of Israel. Logistic growth constants were similar for both species, and experimental brood reduction did not accelerate the growth rate of their nestlings. It is suggested that the predation rate on nests of both species has been sufficiently high to select for maximal growth rate of nestlings. Overall probability of predation was 0.85 on a Desert Lark nest and 0.76 on a Crested Lark nest. The smaller clutch-size of the Desert Lark (3.7) may be an adaptation to a higher predation risk, as compared to that of the Crested Lark (4.6) which is more vigilant and nests in more concealed sites.     

Dispersal history of a spider (Stegodyphus lineatus) across contiguous deserts: vicariance and range expansion

Israel marks a crossroads between three continents encompassing several phytogeographical and zoogeographical zones. In this complex area, the flow of species from different biogeographical regions creates opportunities to study how geographical division and colonization routes affect current distribution and structure of resident populations of organisms associated with desert and arid environments, habitats that may have persisted throughout Pleistocene glacial periods. The present paper analyses the population history of the spider Stegodyphus lineatus in the contiguous Negev and Judean deserts in Israel using allozyme and mtDNA variation. The distinct patterns of variation indicate that Judean and Negev populations are vicariant lineages. The residence time was longer in Judea, where populations were more polymorphic for mtDNA, showed isolation by distance and were less structured than in the Negev. The Negev population, possibly linked to other Mediterranean populations of S. lineatus , consisted of two subdivisions derived from a recent eastward expansion across the central Negev watershed. Despite differences in age and level of structure, all lineages show similar dispersal processes dominated by restricted gene flow. The distribution patterns of allozyme and mtDNA markers are unrelated to geographical patterns of precipitation and vegetation. Rather, they follow large-scale topographic features, namely the water divide between Mediterranean and Afro-Syrian rift drainages and between eastern and western Negev drainages.   © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 739–754.     

10. PROCEEDINGS OF THE SEVENTEENTH ANNUAL GENERAL MEETING OF THE S.A. ORNITHOLOGICAL SOCIETY HELD IN THE COMMITTEE ROOM OF THE PUBLIC LIBRARY. JOHANNESBURG,AT 3 P.M., SATURDAY, 8TH MARCH. 1947

Bruderer, B. 1994. Nocturnal bud migration in the Negev (Israel) a tracking radar study. Ostrich 65: 204–212.

The present publication summarizes the methodological possibilities of tracking radar and describes some features of nocturnal migration at two sites in the Negev, which include anwers to basic questions of bird migration. The directions of spring and autumn migration were practically opposite; only the headings in spring indicated some more compensation for stronger westerly winds. The volume of nocturnal spring migration was only about 65% of autumn migration, which may be an indication of mortality outside tie breeding area. Highest densities of migration at the two radar sites in the Negev Highlands (450 m above sea level) and in the Arava Valley (150 m below sea level) indicated flightlevels adjusted to atmospheric conditions aloft, and not to round level. Due to the trade-wind system, the birds heading southward in autumn flew mainly below flew mainly above 1500 m above sea level, while in spring they tended to make use of the anti-trades at higher altitudes. The decisive factor for altitude choice was the speed of tailwind in spring and autumn; other factors, such as temperature, humidity and pressure had no significant influence on the altitude distributions. With respect to the question of non-stop or intermittent flight across large desert areas, the data show that between the eastern deserts of Egypt and the Sinai/Negev complex the nocturnal migrants maintained their schedule of nocturnal flight and diurnal rest. A few exceptions of nocturnal migrants continuing migration at high altitudes into the day were identified mainly as heron- and gull-type birds. The proportion of waders and waterfowl identified by wing-beat pattern in nocturnal migration is nearly the same at both sites, indicating broad-front migration across the desert. The numbers of birds with continuous wingbeats is, however, so large compared to available estimates of waders and waterfowl wintering in Africa that careful reconsideration of the underlying assumptions in the radar and field estimates is necessary.     

Does seed dispersal limit initiation of primary succession in desert playas?

To investigate the initiation of primary succession in a cold-desert playa-dune complex, we studied the large-scale (2000 m) seed (diaspore) dispersal patterns at Mono Lake, California. Seeds of seven of the ten species reaching the barren playa had wind-dispersal adaptations. Rates of dispersal (numbers of seeds per square metre per day) were as much as three orders of magnitude lower on the playa than in the diverse dune vegetation. However, seed input appeared sufficient to reach potential safe sites on the playa, with a peak input of 66 ± 8 total seeds·m·d. The smooth playa surface, the virtual absence of aboveground barriers, and the high windspeed environment promote the long-distance dispersal of seeds (at least 1300 m for Chrysothamnus spp. and at least 700 m for Sarcobatus vermiculatus). The large spatial scale of sampling revealed a relatively high seed input onto the playa by the dominant pioneer species S. vermiculatus, despite the low abundance of parent vegetation in this region. All of these results implicate low rates of seed entrapment as an obstacle to establishment on this desert playa, rather than a lack of seed input.     

胡杨根系水力提升作用的证据及其生态学意义

生长在塔里木河流域的荒漠河岸林植被虽长期忍受着高温和干旱的威胁, 然而它们却能够一直延续并保存至今。除了植物深根系吸水作用外, 另一个更主要的原因可能就是荒漠河岸林植被存在水力提升的效应。该文采用HRM热比率法茎流仪对3株胡杨(Populus euphratica)主根和侧根的液流速率分别进行了为期4 d的连续监测; 利用自动气象站对微气象因子：风速、空气相对湿度、叶面温度和地表温度进行连续监测; 同时采用了烘干法对不同深度土层在不同时刻的土壤含水率进行了取样分析。试验结果表明：胡杨主根液流在白天和夜间均表现为正值, 相反的, 胡杨侧根液流速率则出现了明显的夜间负向流动。胡杨根系0~120 cm土层土壤水分含量具有下湿上干的变化趋势; 胡杨侧根在夜间发生负向流动后, 土壤含水率显著升高, 尤其在60~120 cm土层中, 4:00土壤含水率上升幅度达到4:00时刻土壤含水率的22%~26%。影响胡杨侧根液流速率的主要气象因子主要是叶面水汽压亏缺。     

Blackaps Sylvia atricapilla stopping over at the desert edge; physiological state and flight-range estimates

Migrating Blackcaps Sylvia atricapilla were mist netted at the desert edge in northern Israel and in Elat (southern Israel) during spring and autumn migrations between 1970 and 1991. Birds in spring in northern Israel were representative of birds that had completed the crossing of the Sahara, while those in Elat still had to cross the 150 km of the Negev Desert, which separates Elat and northern Israel. In autumn, birds captured in northern Israel were representative of those about to cross the Sahara Desert, while those in Elat had already started to cross the desert. The data allowed analysis of seasonal and location differences in the physiological state of Blackcaps before and after crossing the Sahara. Data analysed included body mass, visible fat score and calculated fat content. Autumn migrants were in better physiological condition than spring migrants at both locations, probably as a consequence of their migration route through fertile areas in autumn compared with the crossing of the Sahara in spring. Body mass was less variable after the Sahara crossing in spring than before the crossing in autumn. In spring, 71% and 67% of the birds were fat depleted (fat scores 0 and 1) at Elat and in northern Israel, respectively, while in autumn 34% and 42% were fat depleted. Blackcaps at Elat were 1.6 g lighter than those in northern Israel in autumn and 1.9 g lighter in spring. Potential flight ranges were estimated on the basis of meteorological conditions and flight altitude of passerines above the Negev in Israel (northern Sahara edge) during migration and on a simulation model that considered both energy and water as potential limiting factors for flight duration and distance. The simulation model predicted that half of the Blackcaps that stopped over in Elat and the majority of those that stopped over in northern Israel could not make a nonstop flight over the Sahara Desert in autumn without the assistance of at least an 8 m per s tailwind. Such a wind would still not be sufficient for 34% of the birds in Elat and 42% in northern Israel, and clearly they had insufficient fat reserves to cross the Sahara in a single flight. Although the fattest Blackcaps had accumulated sufficient fat to enable them to traverse the Sahara in a single flight, they probably faced dehydration by at least 12% of their initial body mass when they reached the southern Sahara edge. These birds should use intermittent migration with stopovers at sites with drinking and feeding potential. Their decision to stop over during the day in the desert at sites with shade but without food and water would be beneficial if the meteorological conditions during daytime migration imposed greater risks of dehydration than at night. Spring migrants could not reach their breeding areas in Europe without feeding, but those examined in Elat could cross the remainder of the desert in a single flight.     

Transpiration in Three Eucalyptus Species as a Function of Solar Energy, Soil Moisture and Leaf Area

Three Eucalyptus species indigenous to Australia and successfully acclimatised in the subtropical and northern desert regions of Israel have been grown in pots. Two of them, which contained loess-like desert soil, and one, which contained sandy soil, out of doors, have been exposed to extreme semi-arid climatic conditions with only soil moisture under control. In each species one group has been kept at 15.5% and a second at 7% moisture. The groups grown in water deficient soil had a 31.0–42.8% smaller leaf area and a 2–4 fold lower transpiration rate, the values varying with species. When soil moisture was raised to the same level for the water deficient groups and the plants grown at field capacity an equal or a higher transpiration rate was obtained. This happened although both groups had been exposed to the same intensity of solar radiation and in spite of the significantly smaller leaf area in the groups grown in water deficient soil. In woody xerophytes grown in water deficient soil under arid conditions, the quantity of available soil moisture and the inherent biological properties of the species decide the rate of transpiration and not the area of the foliage or the intensity of solar radiation, or physical evaporation.