Response of a Sonoran riparian forest to a 10-year return flood

In March 1991 a 10-year return flood (368 m 3 s -1 ) occurred in the Hassayampa River, a perennial stream (0.1 m 3 s -1 base flow) within the Sonoran Desert. Depth of the floodwater ranged from 2.64 ± 0.20 m (mean ± SD) near the stream to 0.47 ± 0.31 m in the highest floodplain zone ( Prosopis forest). Flow velocity was 1.7 ± 0.6 m s -1 and 0.9 0.4 m s -1 in these same zones. An average of 8 cm of sediment was depositred on the floodplain, with maximum deposition (to 0.5 m) on densely vegetated surfaces 1—2 m above the water table. Native riparian vegetation showed resistance and resilience to the flood disturbance. Plants on high floodplains (e.g., Prosopis velutina trees and saplings, and Populus fremontii and Salix gooddingii trees) had low mortality. Populus fremontii and S. goddingii ""pole"" trees and saplings were on less aggraded floodplains and sustained varying mortality depending on floodplain elevation and depth of flood waters. For example, P. fremontii pole trees on 1—2-m-high floodplains averaged 6% mortality, compared to 40% for those on low floodplains ( 2 m. Seedlings of Populus fremontii and Salix gooddingii established abundantly after the flood along overflow channels and main channel sediment bars, contributing to age-class diversity for these episodically recruiting species. The exotic species Tamarix pentandra had greater mortality of pole trees (62%) and low post-flood recruitment compared to P. fremontii and S. gooddingii . Survivorship of shrub species also corresponded to floodplain elevation. Zizyphus obtusifolia grew on high-elevation floodplains and had no mortality. Shrub species of lower-elevation floodplains underwent mortality but revegetated after the flood via asexual reproduction. For example, stem density of the dominant shrub ( Baccharis salicifolia ) declined by half but recovered to pre-flood levels by late summer primarily via stem sprouting. Dominant herbaceous plants on stream banks and low floodplains (i.e., the rhizomatous perennial grasses Paspalum distichum and Cynodon dactylon ) similarly compensated for a 50% decline in cover by vegetative spread. The post-flood herbaceous understory vegetation in high-elevation floodplain zones (i.e., Prosopis velutina forests) remained sparse throughout the summer and shifted in composition from nearly monotypic stands of exotic annual species to more divers mixtures of native and exotic annual grasses and forbs.     

Density and biomass of redband trout relative to stream shading and temperature in southwestern Idaho

Density and biomass of redband trout ( Oncorhynchus mykiss gairdneri ) relative to stream temperature were examined in headwater reaches of Big Jacks and Little Jacks Creeks in southwestern Idaho. Stream shading was greater (mean of 80% versus 46%) and solar insolation was lower (mean of 7.9 versus 15.1 mJ · m -2 · day -1 ) in Little Jacks Creek ( P P ≤ 0.07) but increased more rapidly and to higher levels (24° - 26° C) in Big Jacks Creek. Daily maximum water temperatures (23 km downstream of headwater springs) during July 1996 were lower in Little Jacks Creek (ranged from 18° to 22° C) than in Big Jacks Creek (20.2° to 26° C, P P -2 and 25.0 g · m -2 ) compared to Big Jacks Creek (0.3 fish · m -2 and 8.9 g · m -2 , P = 0.01). Trout density was negatively correlated with increases in water temperature ( P = 0.03) and solar insolation ( P = 0.09) in both streams. Trout biomass increased with stream shading and was negatively correlated with solar insolation ( P < 0.1). Warmer water temperatures in Big Jacks Creek were likely due to historical summerlong livestock grazing, which drastically reduced riparian shading.     

Establishment, growth, and early survival of woody riparian apecies at a Colorado gravel pit

Presence of a wetted edge during the period of seedfall was an effective predictor of suitable establishment (defined as germination and survival to the 1st autumn) locations for Populus deltoides subsp. monilifera, Salix amygdaloides, S. exigua, and Tamarix ramosissima seedlings during 3 successive years of a gravel pit revegetation project in Fort Collins, Colorado. At locations predicted to be suitable for establishment, position within the pit (possibly reflecting additional moisture provided by seepage) was a significant factor in determining whether establishment actually occurred. Cover of herbaceous species, which became established at the same time as, or after, woody seedlings, was positively related to probability of establishment for 8 of 11 species-year combinations, probably reflecting more favorable moisture conditions at certain locations. Herbaceous cover also was positively related to seedling height at the end of the 1st summer of growth for 9 of 11 species-year combinations. Neither establishment nor 1st-summer growth was consistently related to overall decline in the water table as estimated by the drop in surface-water level during the growing season. Flooding in the 1st spring after establishment was negatively related to subsequent survival for 5 of 8 species-year combinations. The 4 species established at different elevations in the pit, depending on location of the wetted edge during the period of seedfall, and there was no evidence that differential mortality subsequently altered their distribution along the elevation gradient. However, the primary objective in this study was to restore native woody species, and we attempted to maintain conditions conducive to meeting this objective. Differential postestablishment mortality may be more important in structuring the riparian community in more rigorous riverine environments.     

Observations on woundfin spawning and growth in an outdoor experimental stream

The response of woundfin to different substrates and current speeds was investigated in an outdoor experimental stream. Fish spawned in groups of 15 &ndash; 20 over 5 &ndash; 10 cm rock substrate in a .06 to .09 m/sec current at a depth of 10 cm. Eggs were adhesive on the undersides of the rocks. Fish spawned under these conditions grew to approximately 55 &ndash; 60 mm TL in 5 months.     

Transverse and longitudinal variation in woody riparian vegetation along a montane river

This study explores how the relationship between flow and riparian vegetation varies along a montane river. We mapped occurrence of woody riparian plant communities along 58 km of the San Miguel River in southwestern Colorado. We determined the recurrence interval of inundation for each plant community by combining step-backwater hydraulic modeling at 4 representative reaches with Log-Pearson analysis of 4 stream gaging stations. Finally, we mapped bottomland surficial geology and used a Geographic Information System to overlay the coverages of geology and vegetation. Plant communities were distinctly arrayed along the hydrologic gradient. The Salix exigua Nuttall (sandbar willow) community occurred mostly on surfaces with a recurrence interval of inundation shorter than 2.2 years; the Betula occidentalis Hooker (river birch) community peaked on sites with recurrence intervals of inundation between 2.2 and 4.6 years. The hydrologic position occupied by communities dominated by Populus angustifolia James (narrowleaf cottonwood) was strongly related to age of trees and species composition of understory shrubs. The fraction of riparian vegetation on surfaces historically inundated by the river decreased in the upstream direction from almost 100% near Uravan to <50% along the South Fork of the San Miguel River. In upstream reaches much of the physical disturbance necessary to maintain riparian vegetation is provided by valley-side processes including debris flows, floods from minor tributaries, landslides, and beaver activity. Where valley-side processes are important, prediction of riparian vegetation change based on alterations of river flow will be incomplete.     

Termites live in a pear-shaped world: a response to Platnick

The six primarily Neotropical species groups of the genus Rachispoda are revised, comprising a total of 50 species, of which 35 are newly described. The aequipilosa group comprises nine species in the Neotropical and southeastern Nearctic regions: R. aequipilosa (Duda) comb. n., R. spuleri (Sabrosky) comb. n., and the new species R. alces, R. chisholmae, R. intonsa, R. joycei, R. laureata, R. luciana, and R. paludicola. The divergens group comprises ten Neotropical species: R. decimsetosa (Richards) comb. n., R. divergens (Duda) comb. n., R. multisetosa (Duda) comb. n., R. pluriseta (Duda) comb. n., and the new species R. condyla, R. forficula, R. luisi, R. merga, R. thaliathrix, and R. villosa. The fuscinervis group is a Neotropical and southern Nearctic group of 21 species: R. fuscinervis (Malloch) comb. n., R. schildi (Spuler) comb. n., R. striata (Duda) comb. n., R. trigonata (Spuler) comb. n., R. trochanterata (Malloch) comb n., and the new species R. aeditua, R. amarilla, R. andina, R. cesta, R. clivicola, R. colombiana, R. geneiates, R. justini, R. luminosa, R. meringoterga, R. oreadis, R. recavisterna, R. synoria, R. thermastris, R. trichopyga, and R. zygolepis. The maculinea group comprises seven Neotropical species: R. maculinea (Richards) comb. n., and the new species R. altimontana, R. baezensis, R. caesia, R. kaieteurana, R. lucaris, and R. praealta. The marginalis group contains the single Neotropical species R. marginalis (Malloch) comb. n. The m-nigrum group contains two species in the Neotropical and southeastern Nearctic regions: R. bipilosa (Duda) comb. n. and R. m-nigrum (Malloch) comb. n. Six described species are newly synonymized: Leptocera ensenada Richards (=R. divergens), L. limbinervis Duda and L. ruficornis Duda (=R. fuscinervis), L. paraguayensis Duda and L. weemsi Sabrosky (=R. m-nigrum), and L. rossi Richards (=R. multisetosa).     

A taxonomic and ecologic study of the riverbottom forest on St. Mary River, Lee Creek, and Belly River in southwestern Alberta, Canada

The riverbottom forest community of St. Mary River, Lee Creek, and Belly River in southwestern Alberta, Canada, is a unique ecological entity characterized by poplar species having their major Alberta distribution along these streams. Stands in the community are dominated by three tree species, six shrub species, and nine herb species. Establishment of the community is dependent on climate and substrate; destruction is the result of progressive lateral stream-flow erosion. Soils are sandy loams above gravel, with pH values of 7.7 to 8.0 and soluble salt concentrations of 176 to 458 parts per million. Trees in mature stands averaged 23.0 cm in diameter and 40 years in age; maximum tree age was 250 years. The vascular flora consists of 291 species of which 41 are woody and 250 herbaceous. One species ( Prunus nigra Ait.) new to Alberta and range extensions for 12 species are cited. There are no true community endemic species. Recreational and livestock-raising uses are present community modifiers. Fire is not important in current forest dynamics.     

Redband trout response to hypoxia in a natural environment

Redband trout ( Oncorhynchus mykiss gairdneri ) were observed approximately every 2 weeks in an intermittent southwest Idaho stream between August and December 1991. Instantaneous daytime dissolved oxygen concentration and water temperature declined from 4.0 to Rhinichthys osculus ) were also present in each pool until drying. The response of these fish to such extreme habitat conditions is probably a primary factor accounting for their distribution within arid landscapes.     

Tree size and understory phytomass production in a western juniper woodland

Understory phytomass production in a western juniper ( Juniperus occidentalis ) woodland was examined relative to tree size in central Oregon in 1983 and 1984. Vegetation was sampled in two zones, the canopy zone (beneath the canopy) and the intercanopy zone (the space between canopies), on two adjacent sites—a lower slope site with shallow soil and an upper slope site with deeper soil. Sampling was stratified into three tree size classes. Individual species production was significantly affected by tree size and location relative to tree canopy. Production of bottlebrush squirreltail, bluebunch wheatgrass, cheatgrass, miscellaneous annual grasses, perennial forbs, and annual forbs increased with increasing tree size. Sandberg bluegrass production was greater in the intercanopy than the canopy zone, while production of bottlebrush squirreltail, bluebunch wheatgrass, miscellaneous annual grasses, and both perennial and annual forbs was greater in the canopy zone. Production of cheatgrass was determined by the interaction of tree size and zone. Phytomass relationships were expressed to a greater degree on the upper slope site, where total production exceeded that of the lower slope site by approximately 50% the second year of the study. Individual trees appear to exert a great influence on associated vegetation as western juniper woodlands progress from the seedling (tree establishment) phase to closed stands of mature trees. Original community dominants appear to be spatially segregated beneath tree canopies and associated with large trees, while formerly less common species, such as cheatgrass, come to dominate the entire site.     

Natural enemy assemblages on native and reseeded grasslands in southwestern Montana: a family-level analysis

We conducted a 2-year survey, using sweep sampling and family-level taxon identification, of the predatory and parasitoid insects on grassland sites in the Gallatin Valley of southwestern Montana. The 25 sites were divided into 4 habitat classes: 2 native habitat types ( Stipa comata/Bouteloua gracilis and Festuca idahoensis/Agropyron spicatum ) and 2 that had been reseeded with either crested wheatgrass ( Agropyron cristatum ) or smooth brome ( Bromus inermis ). Our major goal was to make quantitative comparisons of the abundance of insects among native and reseeded habitats. Of 51 families in 5 insect orders identified, 7 Hymenoptera (Encyrtidae, Braconidae, Ichneumonidae, Pteromalidae, Eulophidae, Scelionidae, and Torymidae), 3 Hemiptera (Lygaeidae, Nabidae, and Reduviidae), 1 Coleoptera (Coccinellidae), and 1 Diptera (Asilidae) comprised 90% of the natural enemies sampled. Ordination analyses provided no strong evidence that the 4 habitat classes contained distinct overall natural enemy communities. However, contiguous native and reseeded sites usually had relatively different overall natural enemy assemblages, suggesting that vegetation was often a more important correlate of community composition than was close spatial proximity of sites. Furthermore, several common families exhibited differential abundances across habitat classes in one or both years. For example, in 1989, Eulophidae, Pteromalidae, and Torymidae were more abundant on native Festuca/Agropyron sites, whereas Encyrtidae and Nabidae were more abundant on Festuca/Agropyron sites reseeded with Bromus inermis . Although analyses of insect assemblages classified to the family level provide somewhat limited information on functional ecological differences among habitats, they allow one to survey a broad array of taxa to identify focal groups for future conservation and land management studies.     

The effects of varied densities on the growth and emigration of adult cutthroat trout and brook trout in fenced stream enclosures

We evaluated the effects of various density treatments on adult fish growth and emigration rates between Bonneville cutthroat trout Oncorhynchus clarki utah and brook trout Salvelinus fontinalis in stream enclosures in Beaver Creek, Idaho. We used 3 density treatments (low, ambient, and high fish densities) to evaluate density-related effects and to ensure a response. Intraspecific ambient-density tests using cutthroat trout only were also performed. Results indicated an absence of cage effects in the stream enclosures and no differences in fish growth between ambient-density stream-enclosure fish and free-range fish. Brook trout outgrew and moved less than cutthroat trout in the stream enclosures, especially as density increased. In all 3 density treatments, brook trout gained more weight than cutthroat trout, with brook trout gaining weight in each density treatment and cutthroat trout losing weight at the highest density. At high densities, cutthroat trout attempted to emigrate more frequently than brook trout in sympatry and allopatry. We observed a negative correlation between growth and emigration for interspecific cutthroat trout, indicating a possible competitive response due to the presence of brook trout. We observed similar responses for weight and emigration in trials of allopatric cutthroat trout, indicating strong intraspecific effects as density increased. While cutthroat trout showed a response to experimental manipulation with brook trout at different densities, there has been long-term coexistence between these species in Beaver Creek. This system presents a unique opportunity to study the mechanisms that lead cutthroat trout to coexist with rather than be replaced by nonnative brook trout.     

Factors controlling structural and floristic variation of riparian zones in a mountainous landscape of the western United States

We examined landscape patterns in the physical conditions and vegetative composition of montane riparian zones to identify their most important sources of variation. Information on plant species cover and on physical characteristics that occur at coarse, medium, and fine scales was collected for 144 riparian plots located throughout the Lake Tahoe Basin, which straddles the California-Nevada border in the western United States. Constrained and unconstrained ordination analyses were used to identify the most important correlates of physical form and plant species composition. Through multivariate analysis of environmental variables (principal components analysis), vegetation data (detrended correspondence analysis), and the combined relationship between the environmental and vegetation data (canonical correspondence analysis), we consistently found that the greatest variation occurred along a gradient of decreasing valley width, decreasing stream sinuosity, and increasing stream slope. Although surface characteristics reflected a 2nd important source of variation in physical conditions, plant species distribution was not strongly correlated with riparian surface conditions. Strong correlations among physical variables that occur at different scales, such as between valley form and geofluvial surface and between geofluvial surface and surface conditions, support the use of a physically based hierarchical framework for organizing riparian zones within the landscape. Such a hierarchical framework would be useful for interpreting patterns in riparian structure and process at different scales and could be applied to riparian zones in other mountain landscapes of the western United States and elsewhere. Moreover, our finding that riparian plant species composition is most strongly correlated with environmental variables that occur at coarse to moderate scales, most of which can be derived from existing data, supports the idea that modeling montane riparian community distribution using topographic and remotely sensed data could be useful; however, a large degree of species variation, unexplained by the variables we collected, indicates that other variables, perhaps disturbance regime, should be included in such a venture. Nomenclature: Hickman (1993).     

Interaction between introduced rats and a frugivore bird-plant system in a relict island forest

The seed dispersal system formed by the fleshy-fruited shrub Viburnum tinus L. (Caprifoliaceae) and the bird Erithacus rubecula L. is known to occur in both the Mediterranean basin and the laurel forest of the Canary Islands. The latter is invaded by the ship rat Rattus rattus L. This situation allows (1) the comparison of oceanic island and mainland situations for the bird-plant interaction, and (2) quantification of the possible effects of an invading species on the plant, and thus on the whole seed dispersal system. Fruit removal by birds and rats was studied for V. tinus in a laurel forest of Tenerife during a fruiting season to assess patterns of disperser and predator's use of the plant. Fruits were persistent in time and spontaneous fruit loss rate was low. It was exploited by a reduced frugivorous community. Its fruits were dispersed almost exclusively by E. rubecula at extremely low rates, whereas R. rattus rapidly predated the bulk of the crops. Fruit removal by E. rubecula was influenced by vegetation structure and fruit crop size (higher removal rates from gaps or sparse and low canopy patches, and from larger fruit displays). Fruit predation by R. rattus was not related to microhabitat or individual plant traits. Fruit removal by R. rattus had no apparent influence on the pattern of bird frugivory. However, later in the fruiting season, heavy fruit depletion by rats restrained fruit availability for birds. The mainland (Mediterranean) V. tinus-E. rubecula dispersal system is strikingly different from this island counterpart in: (1) the virtual irrelevance of rodent seed predation, and (2) the comparatively high incidence of bird frugivory by the exclusive seed disperser, E. rubecula.     

Long-term interactions of climate, productivity, species richness, and growth form in relictual sagebrush steppe plant communities

Vegetation trends due to climatic changes are difficult to separate from disturbances caused by varying land uses. To separate climatic influences from livestock grazing and fire disturbances within sagebrush steppe, we compared vegetation structure and productivity during 2 periods (10-year sequences of data from the late 1950s to the late 1960s and 3 years in the early 1990s) at 12 stands within 3 relict areas in or near the Great Rift of southern Idaho. Yearto- year fluctuations in annual net aboveground phytomass accumulation (ANAPA) were considerable in response to varying climate during both periods. More importantly, an apparently significant increase in ANAPA was observed during the latter study period. However, this apparent increase may have been due to the unusually wet conditions of 1993. Throughout both study periods, ANAPA was even more positively correlated with species richness than with precipitation, although both influences were statistically significant. Aggregation of these data by plant growth forms showed that shrubs, particularly sagebrushes, have progressively increased their proportion relative to herbaceous understory. This directional (successional) change in the proportional contributions of growth forms to ANAPA was probably due more to long-term absence of fire at these isolated locations than to any detectable climate change or lack of grazing. This finding reduces our confidence in the use of such areas as reference sites for monitoring or as living examples for restoration efforts, but it does increase our understanding of vegetation dynamics within sagebrush steppe. ACRONYMS. ANAPA—annual net aboveground phytomass accumulations, ANOVA—analysis of variance, ANPP—aboveground net primary production, COV—coefficient of variation, CY—crop year, CYP—crop-year precipitation, ES—ecological site, MANOVA—multivariate analysis of variance, MAT—mean annual temperature, NRCS—Natural Resources Conservation Service, PDSI—Palmer Drought Severity Index, RUE—rainfall use efficiency.     

Fire frequency and the vegetative mosaic of a spruce-fir forest in northern Utah

Fire scar and vegetative analysis were used to construct a fire history for the Engelmann spruce/subalpine fir ( Picea engelmannii/Abies lasciocarpa ) vegetation type of Utah State University (USU) T. W. Daniel Experimental Forest. Three distinct periods of fire frequency were established-presettlement (1700-1855), settlement (1856-1909), and suppression (1910-1990). Mean fire interval (MFI) decreased during the settlement period and greatly increased during the suppression era. The difference was attributed to the influx of ignition sources during the settlement of nearby Cache Valley, located 40 km to the west. Logging and livestock grazing appear to have led to the reduced MFI, which in turn worked as a factor to create the vegetative mosaic now observed on the study area. The increase in MFI during the suppression ear permitted the advancement of shade-tolerant species in the understory of the shade-intolerant lodgepole pine ( Pinus contorta var. latifolia ) and quaking aspen ( Populus tremuloides ). Continued suppression of disturbance from wildfire will allow the lodgepole pine cover type, which experience the lowest MFI during the settlement period, to be further invaded by shade-intolerant species, decreasing spatial stand diversity and increasing the risk of more intense fires.     

Evaluation of wildlife response to a retained mine highwall in south central Wyoming

From 1984 through 1985 a study was made of the influence of a retained mine highwall on a wildlife community in south central Wyoming. Vegetation species richness and diversity were greater near the highwall compared with two adjacent sites 150 m in front of and behind the highwall. However, vegetation abundance (cover) was greater on the two adjacent sites. Small mammal abundance, richness, and diversity were greater on the highwall than on the two adjacent sites. Male bird abundance, richness, and diversity were greatest in front of the highwall (+ 50 m to + 350 m) compared with the highwall and the area behind the highwall.     

Passerine response to roads associated with natural gas extraction in a sagebrush steppe habitat

Natural gas extraction and field development are pervasive throughout the sagebrush steppe of Wyoming. We conducted this study to determine how roads associated with natural gas extraction affect the distribution of breeding songbirds in sagebrush steppe habitat. The study encompassed dirt and paved roads in the Jonah Field II and Pinedale Anticline Project Area in Sublette County, Wyoming. Sites are dominated by Wyoming big sagebrush ( Artemisia tridentata ), and common passerines include sagebrush obligates: Brewer's Sparrows ( Spizella breweri ), Sage Sparrows ( Amphispiza belli ), and Sage Thrashers ( Oreoscoptes montanus ); and non-obligates: Horned Larks ( Eremophila alpestris ) and Vesper Sparrows ( Pooecetes gramineus ). Species relative density was measured using 50-m-radius point counts during spring 1999 and 2000. Four roads with low traffic volumes (700-10 vehicles per day) were surveyed and point counts were centered at variable distances from the road surface such that relative densities were measured 0-600 m from the road's edge. Density of sagebrush obligates, particularly Brewer's and Sage Sparrow, was reduced by 39%-60% within a 100-m buffer around dirt roads with low traffic volumes (700-10 vehicles per day). While a 39%-60% reduction in sagebrush obligates within 100 m of a single road may not be biologically significant, the density of roads created during natural gas development and extraction compounds the effect, and the area of impact can be substantial. Traffic volume alone may not sufficiently explain observed declines adjacent to roads, and sagebrush obligates may also be responding to edge effects, habitat fragmentation, and increases in other passerine species along road corridors. Therefore, declines may persist after traffic associated with extraction subsides and perhaps until roads are fully reclaimed.     

Food habits and dietary overlap of nongame insectivorous fishes in Flint Creek, Oklahoma, a western Ozark foothills stream

Insectivorous fishes were sampled from March, 1983 to February 1984, in Flint Creek, Delaware Co., Oklahoma. There was insignificant habitat segregation between Etheostoma spectabile and E. punctulatum and seasonal habitat partitioning between Cottus carolinae and both darters. Mature E. spectabile ate primarily chironomids and mayflies, whereas juveniles fed primarily on microcrustaceans. Mature E. punctulatum consumed fewer Ephemerella and Leptophlebia than E. spectabile , feeding on Stenonema and other crustaceans. Juvenile E. punctulatum fed mainly on amphipods and mayflies, and juvenile E. spectabile ate primarily microcrustaceans. Cottus carolinae elected primarily mayflies in spring - summer and chironomids in January - February. Coefficients of dietary overlap were highest between larger E. spectabile and juvenile E. punctulatum and lowest between immature E. spectabile and mature E. punctulatum . Overlap between the two darters was significantly correlated with differences in mean prey size (p E. spectabile was also significantly correlated to differences in mean prey sizes. Etheostoma spectabile generally preferred smaller prey than E. punctulatum . All three species avoided Stenelmis . Cottus carolinae avoided microcrustaceans. The study showed that resource partitioning among these three insectivorous fishes is affected by complex interactions of habitat and prey electivity, and prey size selectivity. &nbsp;&nbsp;&nbsp;     

Plant community zonation in response to soil gradients in a saline meadow near Utah Lake, Utah County, Utah

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Patterns of zonation along a saline meadow slope were studied. Different species associations were distributed in five zones along the slope which paralleled Utah Lake. The five zones, distinguished on the basis of dominant species and/or life form, were: saltgrass&ndash;annual weed, saltgrass-alkaligrass, saltgrass-forb, saltgrass, and spikerush. Soil, vegetation, and plant species data were taken. Patterns of change with respect to these factors were observed along the downslope gradient. Soil pH and soluble salts decreased downslope, while organic matter and moisture increased. Individual ions showed varying patterns. Vegetation and species patterns also varied with slope position. Annuals dominated the ridge tops, while sedge and rush cover were restricted to the slope base. Perennial forb distribution was shown to be correlated with elevated levels of micronutrients in the soil.     

Activity patterns and habitat use of pudu deer (Pudu puda) in a mountain forest of south-central Chile

The pudu (Pudu puda) is a small, endemic deer, and the only native ungulate found in Chilean and Argentinean temperate forests. Its ecology, including its double role as an herbivore and as a prey, is poorly known. Therefore, it is pressing to gain a better understanding of the pudu given that its habitat is being transformed rapidly by anthropogenic causes. On a coastal mountain range in south-central Chile, we conducted a habitat use study and examined the activity patterns of the pudu using camera traps. The study area was a large native forest patch, surrounded by commercial plantations which would not constitute a habitat for this deer. Using a sampling effort of 7559 camera days, we found that this deer was largely nocturnal with little activity during daytime. The pudu selected Araucaria forests, and avoided Nothofagus forests. These behaviours suggest that the pudu traded off habitat use patterns and activity time to avoid predation, mainly by puma which is the top predator in the rich local community of carnivores occurring in the latter habitat.