Kahnawa:ke: Factionalism, Traditionalism, and Nationalism in a Mohawk Community

Kahnawa:ke: Factionalism, Traditionalism, and Nationalism in. Mohawk Community . Gerald F. Reid. Lincoln: University of Nebraska Press, 2004. 235 pp.     

Modeling Wolverine Occurrence Using Aerial Surveys of Tracks in Snow

ABSTRACT We designed a novel approach to determining extent of distribution and area of occupancy for wolverines (Gulo gulo) by using aerial surveys of tracks in snow and hierarchical spatial modeling. In 2005 we used a small, fixed-wing aircraft with pilot and one observer to search 575 of 588 survey units for wolverine tracks in approximately 60,000 km² of boreal forest in northwestern Ontario, Canada. We used sinuous flight paths to scan open areas in the forest in the 100-km² survey units. We detected tracks in 138 (24%) of the 575 sampled units. There was strong evidence of occurrence (probability of occurrence >0.80) in 30% of the 588 survey units, weak evidence of occurrence (0.50–0.80) in 12%, weak evidence of absence (0.20–0.50) in 15%, and strong evidence of absence (< 0.20) in 43%. Wolverine range comprised 59% of the study area and area of occupancy was 33,400 km². With information on probability of occurrence and core areas of occupation for wolverines in our study area, resource managers and others can examine factors that influence wolverine distribution patterns and use this information to formulate best management practices that will maintain wolverines on the landscape in the face of increasing resource development. Comparing future survey results with those of our 2005 survey will provide an objective way to assess the efficacy of management practices.     

Effect of precipitation variability on net primary production and soil respiration in a Chihuahuan Desert grassland

Precipitation regimes are predicted to become more variable with more extreme rainfall events punctuated by longer intervening dry periods. Water‐limited ecosystems are likely to be highly responsive to altered precipitation regimes. The bucket model predicts that increased precipitation variability will reduce soil moisture stress and increase primary productivity and soil respiration in aridland ecosystems. To test this hypothesis, we experimentally altered the size and frequency of precipitation events during the summer monsoon (July through September) in 2007 and 2008 in a northern Chihuahuan Desert grassland in central New Mexico, USA. Treatments included (1) ambient rain, (2) ambient rain plus one 20 mm rain event each month, and (3) ambient rain plus four 5 mm rain events each month. Throughout two monsoon seasons, we measured soil temperature, soil moisture content (θ), soil respiration (R_s), along with leaf‐level photosynthesis (A_net), predawn leaf water potential (Ψ_pd), and seasonal aboveground net primary productivity (ANPP) of the dominant C₄ grass, Bouteloua eriopoda. Treatment plots receiving a single large rainfall event each month maintained significantly higher seasonal soil θ which corresponded with a significant increase in R_s and ANPP of B. eriopoda when compared with plots receiving multiple small events. Because the strength of these patterns differed between years, we propose a modification of the bucket model in which both the mean and variance of soil water change as a consequence of interannual variability from 1 year to the next. Our results demonstrate that aridland ecosystems are highly sensitive to increased precipitation variability, and that more extreme precipitation events will likely have a positive impact on some aridland ecosystem processes important for the carbon cycle.     

Do invasive ants respond more strongly to carbohydrate availability than co‐occurring non‐invasive ants? A test along an active Anoplolepis gracilipes invasion front

Invasions by non‐native insects can have important ecological impacts, particularly on island ecosystems. However, the factors that promote the success of invaders relative to co‐occurring non‐invasive species remain unresolved. For invasive ants, access to carbohydrate resources via interactions with both extrafloral nectary‐bearing plants and honeydew‐excreting insects may accelerate the invasion process. A first step towards testing this hypothesis is to determine whether invasive ants respond to variation in the availability of carbohydrate resources, and whether this response differs from that of co‐occurring, non‐invasive ants. We investigated the effect of carbohydrate subsidies on the short‐term foraging and hemipteran‐tending behaviours of the invasive ant Anoplolepis gracilipes (Formicidae) and co‐occurring ant species on an extrafloral nectary‐bearing plant by experimentally manipulating carbohydrate levels and tracking ant recruitment. We conducted experiments in 2 years at two sites: one site was invaded by A. gracilipes prior to 2007 and the other became invaded during the course of our study, allowing pre‐ (2007) and post‐invasion (2009) comparisons. Short‐term increases in carbohydrate availability increased the density of A. gracilipes workers on plants by as much as 400% and reduced tending of honeydew‐excreting insects by this species by up to 89%, with similar responses across years. In contrast, ants at the uninvaded site in 2007 showed a weak and non‐significant forager recruitment response. Across all sites, A. gracilipes workers were the only ants that responded to carbohydrate manipulations in 2009. Furthermore, ant–carbohydrate dynamics at a site newly invaded by A. gracilipes quickly diverged from dynamics at uninvaded sites and converged on those of the site with an established invasion. These findings suggest that carbohydrate resources may be particularly important for A. gracilipes invasions, and underscore the importance of species interactions, particularly putative mutualisms, in facilitating exotic species invasions.     

How useful are the recommended counts and indices in the systematics of the Octopodidae (Mollusca: Cephalopoda)

A morphological dataset based on 14 standard counts and indices was constructed for 68 specimens comprising 12 species of octopuses. This was used to construct distance matrices based on morphological characters. These matrices were compared with genetic distance matrices compiled during molecular phylogenetic analyses of the same 12 species using four mitochondrial and two nuclear genes. Mantel tests showed that there was significant congruence between the phenetic and genetic matrices, suggesting that the genetic signal is reflected in the morphological data set. Matrices of geographical distance were constructed for the 12 species based on the latitude, longitude, and depth of capture of 1726 individuals. These matrices never showed significant congruence with genetic data or with morphological data. Multivariate analysis of the morphological dataset suggests that these counts and indices, traditionally used for discriminating between species in cephalopods, do not show great discrimination at species level, but provide excellent discrimination at the generic level, and, as such, might be useful for resolving the generic placement of some problematic taxa. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 205–218.