Limestone Slopes Research Articles

Whatever Happened to Cheilanthes horridula and Cheilanthes leindheimeri in Oklahoma?

Oklahoma is where several ferns reach their northern or eastern range limits. Among them are two species of lip ferns in the family Pteridaceae, Cheilanthes horridula Maxon and Cheilanthes lindheimeri Hook (Hoagland et al. 2007). C. horridula (prickly lip fern) is primarily found on dry limestone slopes in the Chihuahuan Desert region of northeastern Mexico. Its range extends northward to southwestern Oklahoma. C. lindheimeri Hook (fairy swords) is widespread in central and northern Mexico as well as the southwestern United States (Mickel and Smith 2004). In Oklahoma, the distributions of both are limited, and the numbers of individual plants of each species are likely to be relatively small, compared with other Oklahoma members of the genus Cheilanthes.

Noteworthy Collections: DOMINICAN REPUBLIC

Duranta arida Britt. & Wils. subsp. serpentina Sanders & Judd (VERBENACEAE)—Pedernales Province: Sierra de Baoruco National Park, accessed N of Cabo Rojo on old Alcoa road to Aceitillar, then north on jeep trail (Sendero Baoruco) to Caseta #2. Along trail between park entrance (near Caseta de Control, #4) and Caseta #2, on steep slope below location of sign pointing direction to ‘‘Caseta No. 2.’’ 1,850 m. High elevation pine forest. Lat. 18u12958.20N, Long. 71u34923.10W Datum: WGS84, 3 June 2006, Judd 8130 (FLAS, JBSD, NY). Significance. This collection represents the first documented occurrence of this distinctive subspecies of Duranta arida in the Dominican Republic, where it occurs in the Sierra de Baoruco, on steep rocky slopes in a high montane forest of Pinus occidentalis Sw. The taxon previously was known only from two collections (i.e., Judd 4931: FLAS, JBSD; Proctor 10740: US) in the Massif de la Selle, Haiti (Judd and Sanders 1986, Liogier 1994). The range extension is not really surprising, given that the Sierra de Baoruco, in the Dominican Republic, is the eastward extension of the Massif de la Selle. The habitats of the Haitian and Dominican collections are strikingly similar – both are from steep rocky, limestone slopes, in open forests dominated by Pinus occidentalis. Associated species in the Sierra de Baoruco include Baccharis myrsinites (Lam.) Pers., Chamaecrista selleana (Urb.) Britt. & Rose, Eupatorium illitum Urb., Fuchsia triphylla L., Garrya fadyenii Hook., Hypericum hypericoides (L.) Crantz, Ilex tuerckheimii Loes., Lyonia microcarpa Urb. & Ekman, Myrica picardae Krug & Urb., Pilea spp., and Senecio picardae Krug. & Urb. Associates at the type locality, near Pic la Selle, are similar (see list in Judd and Sanders 1986). The Haitian collections are from 2,000–2,550 m elevation, so the Dominican collection also slightly expands the elevational range of this taxon. This new collection of Duranta arida subsp. serpentina also expands the documented variation in leaf form. The collections from the Sierra de Baoruco have leaves with emarginate to truncate or rounded-mucronate apices, and often have two, small lateral teeth—and thus are often minutely tricuspidate. The leaves of the previously known collections of this subspecies are apically emarginate or tricuspidate. The leaves of plants of Duranta arida subsp. domingensis (Urb.) Mold., which is more widespread on Hispaniola (Liogier 1994), are usually acute to rounded-mucronate. The other distinctive features of D. arida subsp. serpentina, i.e., the prostrate habit, with the branches creeping along the ground (vs. erect stems to 2–3 m tall in subsp. domingensis) and the fruiting calyx open at the apex (vs. usually closed in subsp. domingensis), match those of the Massif de la Selle collections. Thus, the distinctiveness of subsp. serpentina, especially the extremely prostrate habit – with the stems growing along the ground in a snake-like fashion – allows it to be readily distinguished from subsp. domingensis (see keys in Judd and Sanders 1986, and Liogier 1994). Although Duranta arida subsp. domingensis does occur in the Dominican Republic, it was not seen in this part of the Sierra de Baoruco. It is noteworthy, however, that Duranta arida, without designation of subspecies, was included in a list of plants occurring in the Sierra de Baoruco (Garcia et al. 2001). The two subspecies likely are ecologically separated, and thus are probably reproductively isolated. This taxon was found during work on the systematics of Miconieae (Melastomataceae) in the Dominican Republic, and this fieldwork was supported by NSF Grant DEB-0515636. I thank Milciades Mejia and the herbarium *email address: wjudd@botany.ufl.edu Received July 2, 2007; Accepted August 21, 2007. CASTANEA 73(1): 40–41. MARCH 2008

RECLASSIFICTION OF MONSOON TROPICAL FORESTS IN SOUTHERN YUNNAN, SW CHINA

Southern Yunnan is located biogeographically at a transitional zone between tropical Southeast (SE) Asia and subtropical East Asia, and though far north of the Equator and at a relatively high altitude, has a rich and diverse tropical flora. The terminology used to describe the different tropical forest types in the region are confusing because the classification schemes used come from different disciplines. Using the classification scheme of tropical plant formations by Schimper (1903) and Richards (1996) , which is based primarily on climatic factors, we discuss a new classification scheme of the tropical forests in southern Yunnan. Horizontal vegetation types in southern Yunnan are represented by tropical seasonal rain forests and monsoon forests. The tropical seasonal rain forest is a tropical Asian rain forest at altitudinal and latitudinal limits, while the monsoon forest is considered to be a transitional vegetation type between tropical rain forests and savannas based on their physiognomy and distribution. The monsoon forest is largely leafless during the dry season. The forests that occur on the middle and upper limestone slopes in southern Yunnan, which was called a monsoon forest in some Chinese botanical references, is reclassified as a seasonal moist forest. These forests are not equivalent to classical monsoon forests in their physiognomy, despite of the fact that it is affected by seasonal dryness and contains a high percentage of deciduous trees. The floristic composition also is different from monsoon evergreen broad-leaved forests in the region. This limestone forest, which abuts the seasonal rain forest on lower slopes and in the limestone valleys, is an altitudinal vegetation type on limestone bedrock in southern Yunnan.

Earthquake-induced slope vibration and its relationship with material properties, slope height, and input wave frequency

The relationship of the amplification of vibration on the surface with the slope geometry, earthquake input signal (mainly frequency of the wave) and the material property of the slope is studied using the finite difference program FLAC. A sinusoidal wave with acceleration of 1 m/s2 is applied for the duration of 0.25 sec. The influence of varying input frequency is investigated applying the frequencies in the range of 3 Hz to 15 Hz. The variation of amplification due to the change in shear modulus of the material in the slope and that due to slope height is also investigated.
 It is found that the crests of the higher slopes are amplified most by the lower input frequency and smaller slopes are amplified most by the higher input frequency. The overall magnitude of the amplification is maximum for smaller slopes when input signals of higher frequency are applied. The generation of standing waves at certain harmonic frequencies could be the reason behind such a high amplification. It is also seen that the amplification peaks of vibrations repeat at different slope heights, which is considered reflection of the harmonic effect. A clear resonance effect is seen when the amplification of vibration is plotted against the shear modulus. The peaks of such amplification also repeat periodically as a result of varying shear modulus. Present study provides some preliminary relationship of amplification with slope height and shear modulus of the material in the slope. The horizontal amplification of vibration as much as 17 (horizontal acceleration in the order of 1.7 g) is obtained at the crest of normal limestone slope with 20 m height when an input signal of 15 Hz frequency is applied. It is also revealed that for extremely lower values of shear modulus, there is mostly attenuation instead of amplification and for extremely high values of shear modulus, amplification is negligible as compared to the certain range of intermediate shear modulus. Maximum amplification in the order of 6.5 (horizontal acceleration of 0.66 g) is achieved for the shear modulus of 3000 MPa with slope height of 40 m when the input acceleration of 0.1 g is applied. This type of relationship is believed to have great importance for seismic microzonation study as the results might be used along with the digital elevation model for separating different zones of hazard levels. However, one should be aware that this result is for the slope with particular combination of material properties, geometry and earthquake input signals, and generalisation could lead to misleading results.

A new arborescent Euphorbia (Euphorbiaceae) from northern Somalia

Euphorbia spissa, sp. nov., a tree known from a single population on a rocky limestone slope in northern Somalia, is described and illustrated. The species is compared with the widespread E. tirucalli, as well as with E. cameronii and E. bariensis (endemics in Somalia), E. arbuscula (endemic on Socotra), and E. uzmuk (endemic in northern Yemen).

New species of Boswellia and Commiphora (Burseraceae) from Somalia

The new species Boswellia globosa, from the foothills of the limestone escarpment along the Gulf of Aden in northern Somalia, and Commiphora lacerata, from a rocky limestone slope near the coast of the Indian Ocean in north‐eastern Somalia, are described and illustrated.

A new species of Scutellaria (Lamiaceae) from Somalia

The new species Scutellaria somalensis, from limestone slopes in north‐eastem Somalia, is described and illustrated.

A new species of Rhytidocaulon (Apocynaceae) from Somalia

Rhytidocaulon baricum, sp. nov., from open rocky limestone slopes in northeastern Somalia, is described and illustrated.

Caralluma lamellosa (Apocynaceae), a remarkable new species from Somalia

The new species Caralluma lamellosa, from a rocky limestone slope about 200 m a.s.1. in north‐eastem Somalia is described and illustrated. The plant is reminiscent of C. furta in habit, but its outer corona, with undivided linear‐oblanceolate lobes opposite to the anthers and at first examination looking like lamellae on the corolla tube, is unparalleled among stapeliads.

An Evaluation of Alternative Image Classification Techniques for the Identification and Mapping of Tropical Savanna Landscape in Northern Australia

Landsat MSS, TM and SPOT XS imageries were used in conjunction with unsupervised, supervised and hybrid classilication techniques to classify land cover types in semi‐arid savannas of Mathison Pastoral Station in the Katherine region of northern Australia. Accuracy assessment was based on field data from 246 ground survey sites over a 745‐km2 study area. Of 14 land cover classes identified by traditional mapping means, all combinations of imageries and classification techniques differentiated at least seven land cover types. The overall accuracy for these classifications ranged between 43% and 67%. SPOT XS image delivered the best accuracy followed by TM and MSS; unsupervised classification performed better than supervised and hybrid methods. User's and producer's accuracy of individual land units ranged from 0% to 100%. Riparian woodlands, woodland on limestone slopes, shrubland on clay plains, woodland on limestone plains and shadows were the best‐mapped classes. The land units that were associated with undulating hills were not mapped accurately. However, incorporation of a digital elevation model (DEM) in a GIS improved the overall accuracy. The user's and producer's accuracy of dominant land cover types were also enhanced. The classification results and the efficacy of the techniques at Mathison were similar to those found for a nearby semi‐arid area (Kidman Springs) about 200 km from Mathison. However, the overall accuracy was lower at Mathison than at Kidman Springs. Spectral classification masks were developed from the SPOT XS and TM imageries at Kidman Springs, and were applied to classify SPOT XS and TM imageries at Mathison. Initial results showed that the classification mask could be successfully extrapolated to map dominant land cover types but only with moderate accuracy (50%).

Notes on Pluchea (Asteraceae) in Somalia and Ethiopia

The new species Pluchea littoralis from limestone rocks and slopes facing the sea along the coast of north‐eastern Somalia and P. lucens from rocky slopes on gypseous ground at 1500–1550 m altitude in northern Somalia, are described and illustrated. The new combinations P. kelleri (=Blurnea kelleri) and P. somaliensis (=Blumea somaliensis) are made and a description is provided for P. kelleri. P. sarcophylla is resurrected and typified, and the circumscription of P. heterophylla is changed and an illustration of the species is provided. P. pinnatifida and Conyza stenodonta are treated as synonyms of P. arabica, and P. serra is placed in synonymy of Iphionopsis rotundifolia.

Runoff generation, sediment movement and soil water behaviour on calcareous (limestone) slopes of some Mediterranean environments in southeast Spain

An interpretation of soil hydrology and erosion data obtained from limestone areas in southeast Spain is presented in the framework of recent hypotheses on runoff generation mechanisms in Mediterranean environments. The main objective is to synthesise and harmonise the data in theoretical concepts or behavioural models of hydrological functioning of Mediterranean limestone slopes. For this purpose, data were collected in a typical limestone area, with climatic characteristics ranging from subhumid to semiarid. Several sites were chosen with comparable slopes, vegetation and soils along a transect of 20 km to carry out several research projects. The data discussed in this paper consist of information on water redistribution within the soil profiles obtained from long duration (up to 5 h) rainfall simulation experiments with continuous monitoring of soil moisture at different depths. Runoff and sediment concentration data were obtained (i) from rainfall simulation experiments with different antecedent soil moisture conditions and (ii) as natural results from open Gerlach plots on runoff and sediment movement over 4 years. Three conceptual models of water redistribution during the infiltration process could be observed, two of them imply nonuniform water redistribution within the soil profile due mainly to macropore flow caused by specific soil surface characteristics. At the plot scale, runoff generated in bare patches is mainly Hortonian. In plots with previously wetted soils or soils with high infiltration capacities, the generated runoff implies the saturation of the upper soil. Both types of runoff are discontinuous through time and space. The runoff generation mechanisms at the slope scale have been synthesised into two conceptual models: a Hortonian discontinuous runoff model that takes place in the most degraded slopes or during high intensity rain events and, a mixed runoff generation model in less degraded slopes or in previously wet soils, where infiltration excess runoff as well as saturation excess runoff can happen on the same slope. In both cases, slopes behave as a patchwork of runoff and runon areas, the size of the runoff or runon patches is dependent on the climatological conditions. These control the hydrological disconnection between different parts of the slopes. Hortonian and saturation runoff can both be generated and infiltrated downslope.

Two new species of Jatropha (Euphorbiaceae) from Somalia

The new species Jatropha miskatensis, from limestone slopes of the Cal Miskaat Range in north‐eastern Somalia, and J. marmorata, from bushland on shallow soil over limestone just south of the Nugaal valley in north‐eastern Somalia, are described. An illustration is provided for J. miskatensis.

Ten new species of Commiphora (Burseraceae) from Somalia

The following new species are described: Commiphora arenaria from bushland on sand in south‐central Somalia, C. gardoensis from limestone slopes in the Qardho area in north‐eastem Somalia, C. stellatopubescens from bushland on limestone outcrops or stony ground in the Hiiraan Region in south‐central Somalia, C. spinulosa from limestone rocks on the escarpment along the Gulf of Aden in northeastern Somalia, C. lobatospathulata from bushland on sand in central and south‐central Somalia, C. quercifoliola from bushland on shallow soil over limestone near Eil in north‐eastem Somalia, C. chiovendana from bushland in northern and central Somalia, C. multifoliolata from limestone hills and ridges in south‐westem Somalia, C. murraywatsonii from limestone outcrops near Hobyo in central Somalia, and C. kucharii from bushland on shallow soils over limestone in central and southern Somalia.

A new species of Cyphostemma (Vitaceae) from Somalia

Cyphostemma cornus‐africani, sp. nov., from rocky limestone slopes in north‐eastern Somalia, is described and illustrated.

Kilise Tepe 1994

The Göksu valley (Fig. 1), which furnishes one of the two main routes from Turkey's southern shore through the Taurus to the Konya plain and the rest of the central plateau, must be deemed one of the country's national treasures. The clear turquoise ribbon of the river threads its way south-eastwards from high in the mountains west of Ermenek to reach the Mediterranean at Silifke, or rather at the mouth of the delta it has created to the south of the classical and modern town. The valley itself, however, is by no means uniform, nor is the road which follows it. Coming from the interior, the traveller leaves the Konya plain not far south of Karaman, and after a gentle climb to the pass at Sertavul, begins to descend thickly pine-grown slopes high on the eastern shoulders of the valley, with the Göksu itself glimpsed occasionally flowing far below. Dropping steeply down, leaving the monastery of Alahan high above one to the left, one passes into a very different landscape around the regional centre of Mut, Roman Claudiopolis (earlier Ninica, see Mitchell 1979). Here the Göksu is joined from the west by the Ermenek Su, and the narrow valleys of their upper courses give way to a wide, low-lying basin, where the stream has cut through one terrace after another, to yield a curiously desert landscape in which remaining patches of the geological terraces, harbouring olive groves and cereal crops in early summer, stand isolated from one another by high eroded scarps, whose steep bare yellow and white limestone slopes are studded only sparsely with pines and low evergreen bushes like prickly oak.

Impacts of primary deforestation on limestone slopes in nothern Vancouver Island, British Columbia : Harding, K A; Ford, D C Environ GeolV21, N3, June 1993, P137–143

Impacts of primary deforestation on limestone slopes in nothern Vancouver Island, British Columbia : Harding, K A; Ford, D C Environ GeolV21, N3, June 1993, P137–143

A Portable Device for the Simulation of Air Frosts at Remote Field Locations

Natural late frosts can have important ecological and economic effects. A device is described which can simulate night-time air frosts at remote, field locations. It is composed of an insulated cloche, vortex tubes and a compressed air generator. Vortex tubes are commercially available devices that split a single compressed air stream into two, one hot and one cold. In a pilot study, five replicate 2 × 2 m areas of grassland on a limestone slope in Derbyshire were subjected to a −2-8°C (range ± 1.1 °C) air frost for 3 h in early June 1992. Initial subjective observations on the vegetation suggested that the effects were similar to those of natural late frosts observed in previous years

Impacts of primary deforestation upon limestone slopes in northern Vancouver Island, British Columbia

Effects of deforestation upon slopes in limestones and in volcanic rocks in the Benson River valley, northern Vancouver Island, have been investigated quantitatively. Postlogging soil erosion and vegetal regeneration success were assessed by measuring soil depth, percent bare rock and moss cover, and the numbers and diversity of trees, shrubs, and plants on 25 sampling sites, each containing ten measuring quadrats selected at random. Sixteen sites were on the Quatsino Formation, a well-karstified limestone, and nine on the Karmutsen Formation of basaltic lavas. Eight sites were of virgin forest, 16 were logged between 1970 and 1983, and one (on limestone) was logged in 1911. Both bedrock types were significantly affected by the cutting. There was greater loss of soil and an increase in bare rock on the limestones. Erosion was increased significantly by burning on the limestones but not on the volcanics. Within-group comparisons on the limestones determined that steeper slopes and harder burned areas suffered the most and are slowest to regenerate. Volume of timber on the 1911 site was 19 percent of that in similar uncut forest sites. It appears that complete recovery on the barren limestone slopes will require at least some centuries.

Four new species of Jatropha (Éuphorbiaceae) from Somalia

The following new species, all related to the Somali endemic Jatropha nogalensis in/. sect. Spinosa subsect. Spinosae, are described and illustrated: J. humifusa (coastal dunes of central Somalia), J. inaequispina (north‐central Somalia, on limestone), and J. collina and J. spinosissima (both rocky ground in north‐eastern Somalia). A hybrid between J. humifusa and the rather distantly related J. pelargoniifolia is reported.