The first quantitative taxonomy of phytoliths from Miombos is presented here, including new types and constituting the most extensive phytolith key for any African ecoregion. Evidence is presented that local woody species are hypervariable silica producers and their phytolith morphotypes are highly polymorphic. The taxonomic significance of these phytoliths is largely poor, but there are important exceptions that include the morphotypes produced by members from >10 families and orders. The typical phytolithic signal that would allow scientists to identify ancient woodlands of 'Zambezian' affiliation comprises only half of the original number of phytoliths originally produced and might favour the more resilient blocky, cylindroid, globular and tabular forms.

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Abstract:We examined the ecological and physical characteristics of den sites for 13 adult kit fox (Vulpes macmtis) in westem Utah from December 1998 to February 2001. We also compared current and historical den distribution among habitat types. The number of den sites used was not influenced by home-range size (P = 0.11) or season (P = 0.40), but was influenced by geographical area. Home-range size was smallest (P = 0.007) and the number of dens used was greatest (P = 0.009) in mountainous areas. Ecological and physical characteristics of single-use dens (n = 30) were compared with those of multiple-use (n = 53) and natal dens (n = 8). Characteristics that differed between den types included number of entrances (P = 0,0001). diameter of entrances (P = 0.003), and height of vegetation along transects ( P = 0.0001). Natal den entrance azimuths were weighted towards a northwesterly aspect ( P = 0.0022); however, single-and multipleuse den exits appeared to be randomly distributed. Historical changes in kit fox den site selection have occurred since 1959 (P < 0.0001). We characterized more dens in invasive grasslands and fewer in greasewood (Sarcobarus vermiculatus) habitats than previously described. The conversion of native habitat to grassland and the increase in coyote population may have altered kit fox distribution to include mountainous areas not previously described.Resume : Nous avons etudie les caracteristiques ecologiques et physiques des sites occupCs par les terriers de 13 renards nains (Vulpe.7 rnacrotis) adultes dans I'ouest de I'Utah, de decembre I998 a fevrier 2001. Nous avons tgalement compart la rtpartition actuelle des terriers en fonction des divers habitats 2 leur repartition dans le passe. Le nombre de sites occupes par des terriers n'est pas influence par la taille du domaine vital (P = 0.1 1). ni par la saison (P = 0.40). mais plutdt par la region geographique. C'est en zone montagneuse que nous avons trouve les domaines les plus restreints (P = 0,007) et le nombre de temers occupes le plus grand ( P = 0,009). Les caracteristiques ecologiques et physiques des terriers occupis une seule fois (n = 30) ont CtC comparies B celles des terriers utilists a plusieurs reprises (n = 53) et a celles des temers natals (n = 8). Les sites varient par le nombre (P = 0,0001) et le diametre (P = 0,003) des entrees et par la hauteur de la dgetation le long de transects ( P = 0,0001). Les azimuts de I'entree d'un terrier natal ont tendance 2 s'orienter vers le nord-ouest ( P = 0,0022); cependant, les sorties des temers a utilisation unique ou multiple semblent reparties aMatoirement. Depuis 1959, les renards on1 modifit leur choix d'habitat pour etablir leur terrier ( P < 0,0001). Nous awns trouve plus de nids dans les prairies herbeuses qui envahissent la region et moins dans les zones de sarcobates vermiculCs (Sarcobarus vermiculatus) qu'auparavant. Ce son1 probablement la conversion de I'habitat indigene en terrain herbeux et I'augmentation de la population de coyotes qui ont Ctendu la repartition des rena...

This paper describes topsoil phytolith assemblages from 25 loci underneath miombo woodlands on an eco-transect intersecting the Mozambican Rift along a geographical, altitudinal, climatic and botanical gradient. We provide the first comprehensive overview of the phytolith spectrum that defines northern Mozambique's Zambezian floristic zone. Our classifying criteria derive from comparison with previously described and quantified reference collections of trees and grasses growing in the study area. We characterize the sedimentological and soil features of the matrices where phytoliths are found, establishing correlation among geo-edaphic variables and phytoliths. Descriptive statistics along with nonparametric and parametric statistical analyses evaluate phytolith grouping criteria, variation, robustness, and membership. From a taphonomic perspective, we attest that topsoil phytolith assemblages are polygenic and do not represent an episodic snapshot of extant vegetation, but a palimpsest from plants representing various disturbance episodes, succession stages, and ecological trends. Phytoliths retrieved from Mozambican miombo soils do not seem to trace altitudinal, temperature, or precipitation gradients, and no significant differences exist between highland and lowland phytolith assemblages. This article provides a phytolith analog for woodland environments that can guide future paleoenvironmental research. It also confirms that phytolith analysis is able to detect shifts in the woodland/grassland interface.