Population genetic and conservation of the native xerophytic species Balsamocarpon brevifolium from the Southern Atacama Desert, Chile

The similarities and differences in seed bank structure across four locations in the North American deserts (Curlew Valley, Utah in the Great Basin; Rock Valley, Nevada in the Mojave Desert; Silverbell, Arizona in the Sonoran Desert; and Jornada, New Mexico in the Chihuahuan Desert) were compared using published data. Species composition at Curlew Valley was most distinctive among the four study sites. In all four sites, average seed size decreased in this order: shrub, herbaceous perennial, and annual species. Mean seed sizes were similar across the Curlew Valley, Rock Valley and Silverbell sites but much smaller at the Jornada site. Most species have small seeds, but the number of seeds varied greatly among these small-seeded species; i.e. seeds of these species could be highly abundant or very rare in the seed banks. In contrast, very few species have large seeds and the seeds of these species were always rare. The possible roles of underlying soil and climatic factors in structuring desert seed bank structure are discussed.

The objective of this baseline study was to use pitfall traps to examine the taxonomic composition and abundance of arthropods in the Quebrada del Morel private protected area located in the Atacama Region (Chile). The study area was divided into 10 vegetationally and pedologically contrasting sites: coastal steppe (CS), ravine bottom (RB), dunes with Prosopis flexuosa (PF), sandy-bottomed ravine (SBR), dunes with Skytanthus acutus (SA), coastal range (CR), piedmont with Nolana sp. (PN), inland dunes (ID), steppe with Nolana sp. (EN), and steppe with Atriplex sp. (EA). A total of 2187 specimens were captured, belonging to 73 species in 31 families. Of these 73 species, 26 belonged to Arachnida, and 47 to Insecta. The two dominant orders of the Arachnida assemblage were Solifugae (22.8% of total capture) and Araneae (5.7%). Insecta accounted for 69.1% of the total capture and was dominated by two orders: Coleoptera (33.8%) and Orthoptera (21.9%). The most abundant arthropod families were the solifuge Mummucidae (22.5%), the coleopteran Tenebrionidae (19.4%), and the orthopteran Gryllidae (18.8%). Particularly important among these families was Tenebrionidae which was represented by 18 species and 11 genera. The sites with the highest abundance of tenebrionids were PF (61.9%) and SBR (11.8%). The highest species diversity was observed in SBR (13) and PF (11). The differences in vegetation between the sites were clearly reflected in the numerical contribution of most taxa. This information will help implement compensation actions, develop a reclamation plan, and consolidate a conservation management plan for the Quebrada del Morel private protected area.

Abstract The Huaynaputina eruption (1600 AD, Moquegua, S Peru) in the northern Atacama Desert denuded the Omate area of all vegetation and deposited deep pumice layers. Data on the flora, climate and soil characteristics of these slopes near Omate at 1600–2600 m a.s.l. are provided. Fifty-nine angiosperm species established themselves on the pumice slopes in the past ca. 400 years, with the bulk of the small and herbaceous species and several species new records for Peru. Three Omate sites were sampled in both a dry and a wet year and species numbers differed widely (14 versus 45 spp.). Among areas compared floristic composition is most similar to the Lomas de Tacna, and has less in common with geographically closer Lomas or Sierra formations. Nine species represent highly disjunct populations (200–>700 km) from their nearest known living populations in central Peru, Chile, or Argentina/Bolivia and appear to have reached the area via long-distance dispersal. Abiotic conditions may have played an important role in limiting the establishment of species from the neighboring vegetation. Four taxa on the pumice slopes show clear morphological differences to populations elsewhere, two of them may represent neoendemics of the Omate pumice, indicating rapid morphological divergence.

Aim  This study presents a phytogeographical characterization of the vine flora of two lower North American desert regions as a biogeographical framework for further ecological inquiry into desert vines. Location  The phytogeography of the vine flora of the Sonoran and Chihuahuan Deserts was c haracterized based on 263 known species. Methods  Checklists of the vines of each desert were developed. Represented genera were then grouped into 10 phytogeographical elements based on worldwide distribution patterns. To compare the floristic composition of the desert floras, an index of species similarity was calculated. Results  About a third more species of vines occur in the Sonoran Desert than in the Chihuahuan Desert. Based on the analysis, cosmopolitan genera are the only group more numerous in absolute terms in the Chihuahuan Desert than in the Sonoran Desert. Tropical elements are represented in about the same proportion in each desert as the number of species, however, nearly twice as many pantropical and neotropical genera are represented in the Sonoran Desert as in the Chihuahuan Desert. Proportionately, more genera of temperate elements occur in the Chihuahuan Desert than in the Sonoran desert, although the absolute number of genera is slightly higher in the latter. Main conclusions  As these deserts are relatively recent ecological formations and as vines evolved in forest ecosystems, the composition of the desert vine floras is the result of the interaction between historical vegetation types, their constituent taxa and climatic and geological history. The main differences in the vining floras of the present-day Sonoran and Chihuahuan Deserts appear to be the result of greater historical influence in the Sonoran Desert of (1) tropical vegetation types and (2) the emergence of the Gulf of California. The Chihuahuan Desert vine flora seems to be the result of (1) a more pronounced historical temperate vegetation, (2) the lack of an important isolating event, such as the creation of the Baja California peninsula, and (3) a cooler climate with shorter growing seasons.

SUMMARY The present article informs about the floristic-structural model of vegetation in the valley of Cayurranquil river, area of Cayurranquil (35o58’11’’ S / 72o38’25’’ W), Cauquenes, VII Region, Chile, so far unknown by literature. The number of vascular plant species was registered for 11 locations in spots of 100 m 2 . Then, the phytogeographical origin of the species, life forms, biological spectrum and stratification were analyzed. The flora is composed by 63 species, 93.7% of them native. The species are arranged in the following strata: arboreal (24 species), shrubs (16 species), herbaceous (14 species) and climbers (9 species). Phanerophyts and hemicryptophyts are the dominant life forms. The vegetation is a mixed wood with elements of Valdivian and Mediterranean origin. A variation of Lapagerio-Aextoxiconetum from Valdivian forest and Pitavio-Nothofagetum dombeyi from the central zone with endemic species such as Pitavia punctata Mol. and Gomortega keule were found as sintaxa.