We used molecular techniques to examine the ectomycorrhizal fungal community associated with pinyon pine (Pinus edulis) growing in two soil types in a semiarid region of northern Arizona: cinder soils low in nutrients and moisture, and sandy‐loam soils with higher moisture and nutrient levels. Pinyon performance (e.g., growth, reproduction, water stress) has been shown to be markedly lower in cinder than in sandy‐loam environments. Fungal community composition and richness were determined using RFLP (restriction fragment length polymorphism) analysis of ectomycorrhizal root tips collected from three sites within each soil type. Several patterns emerged from these analyses. First, communities in both cinder and sandy‐loam soils were dominated by one or a few abundant ectomycorrhizal types, a species abundance pattern common to many plant and animal communities. Second, unlike the pattern for many other organisms, ectomycorrhizal fungal type (species) richness was not correlated with measures of ecosystem productivity such as soil nutrient and moisture levels; cinder and sandy‐loam soils had similar numbers of ectomycorrhizal fungal types (range of 15–19 fungal types for both soil types). Third, soil type and fungal community composition were linked, as cluster analysis demonstrated greater similarity of fungal communities from sites within soil types than between them. Differential amplification using primers with enhanced specificity for basidiomycetes indicated that an average of 85% of the ectomycorrhiza found at the sandy‐loam sites were members of the subphylum Basidiomycotina, whereas over half (mean = 52%) of the ectomycorrhiza at the cinder sites were formed by members of other fungal groups, probably the subphylum Ascomycotina. Fourth, a preliminary survey of 14–45 ectomycorrhizal root tips from each of 20 trees at one cinder site indicated that trees were dominated by one or a few ectomycorrhizal RFLP types. However, the same RFLP types did not dominate on all trees, and dominant types showed considerable spatial variation. Fifth, the RFLP patterns of some fungal sporocarps matched those of ectomycorrhizal root tips, but many did not, indicating that many of the ectomycorrhizal fungi at these sites fruit infrequently, whereas other fungi with more abundant sporocarps may not form ectomycorrhiza. This emphasizes the need to characterize the ectomycorrhizal communities formed on the plant roots themselves, rather than characterization based on sporocarps alone, particularly in arid environments. Finally, the differences in ectomycorrhizal fungal communities we observed between soil types supported the concept that conserving fungal diversity requires conservation of host plant species over their entire range, not just typical sites. If future studies corroborate these patterns, our results suggest that abiotically stressful environments are important to include in these conservation efforts.

We used molecular techniques to examine the ectomycorrhizal fungal community associated with pinyon pine (Pinus edulis) growing in two soil types in a semiarid region of northern Arizona: cinder soils low in nutrients and moisture, and sandy-loam soils with higher moisture and nutrient levels. Pinyon performance (e.g., growth, reproduction, water stress) has been shown to be markedly lower in cinder than in sandy-loam environments. Fungal community composition and richness were determined using RFLP (restriction fragment length polymorphism) analysis of ectomycorrhizal root tips collected from three sites within each soil type.Several patterns emerged from these analyses. First, communities in both cinder and sandy-loam soils were dominated by one or a few abundant ectomycorrhizal types, a species abundance pattern common to many plant and animal communities. Second, unlike the pattern for many other organisms, ectomycorrhizal fungal type (species) richness was not correlated with measures of ecosystem productivity such as soil nutrient and moisture levels; cinder and sandy-loam soils had similar numbers of ectomycorrhizal fungal types (range of 15-19 fungal types for both soil types). Third, soil type and fungal community composition were linked, as cluster analysis demonstrated greater similarity of fungal communities from sites within soil types than between them. Differential amplification using primers with enhanced specificity for basidiomycetes indicated that an average of 85% of the ectomycorrhiza found at the sandy-loam sites were members of the subphylum Basidiomycotina, whereas over half (mean ϭ 52%) of the ectomycorrhiza at the cinder sites were formed by members of other fungal groups, probably the subphylum Ascomycotina. Fourth, a preliminary survey of 14-45 ectomycorrhizal root tips from each of 20 trees at one cinder site indicated that trees were dominated by one or a few ectomycorrhizal RFLP types. However, the same RFLP types did not dominate on all trees, and dominant types showed considerable spatial variation. Fifth, the RFLP patterns of some fungal sporocarps matched those of ectomycorrhizal root tips, but many did not, indicating that many of the ectomycorrhizal fungi at these sites fruit infrequently, whereas other fungi with more abundant sporocarps may not form ectomycorrhiza. This emphasizes the need to characterize the ectomycorrhizal communities formed on the plant roots themselves, rather than characterization based on sporocarps alone, particularly in arid environments. Finally, the differences in ectomycorrhizal fungal communities we observed between soil types supported the concept that conserving fungal diversity requires conservation of host plant species over their entire range, not just typical sites. If future studies corroborate these patterns, our results suggest that abiotically stressful environments are important to include in these conservation efforts.

This paper discusses the interaction between plants and the rodents that scatterhoard their seeds (i.e. cache seeds individually or in small groups in numerous cache locations) can be viewed as a conditional mutualism that depends in part on two factors that can vary in time and space: (1) the relative abundance of seeds versus scatterhoarders (the seed:scatterhoarder ratio) and (2) the potential recruitment of seedlings that are not handled by scatterhoarders versus recruitment when seeds are handled by scatterhoarders. A simple conceptual model of how the outcome of the scatterhoarder-plant interaction depends on both the relative abundance of each partner and the challenges to recruitment faced by the plant is presented.

We used 38,709 fixes collected from December 2003 through June 2006 from 44 elk (Cervus elaphus) fitted with Global Positioning System collars and hourly traffic data recorded along 27 km of highway in central Arizona, USA, to determine how traffic volume affected elk distribution and highway crossings. The probability of elk occurring near the highway decreased with increasing traffic volume, indicating that elk used habitat near the highway primarily when traffic volumes were low (<100 vehicles/hr). We used multiple logistic regression followed by model selection using Akaike's Information Criterion to identify factors influencing probability of elk crossings. We found that increasing traffic rates reduced the overall probability of highway crossing, but this effect depended on both season and the proximity of riparian meadow habitat. Elk crossed highways at higher traffic volumes when accessing high quality foraging areas. Our results indicate that 1) managers assessing habitat quality for elk in areas with high traffic‐volume highways should consider that habitat near highways may be utilized at low traffic volumes, 2) in areas where highways potentially act as barriers to elk movement, increasing traffic volume decreases the probability of highway crossings, but the magnitude of this effect depends on both season and proximity of important resources, and 3) because some highway crossings still occurred at the high traffic volumes we recorded, increasing traffic alone will not prevent elk‐vehicle collisions. Managers concerned with elk‐vehicle collisions could increase the effectiveness of wildlife crossing structures by placing them near important resources, such as riparian meadow habitat.

Genetic differences within and among naturally occurring populations of wild turkeys (Meleagris gallopavo) were characterized across five subspecies' historical ranges using amplified fragment length polymorphism (AFLP) analysis, microsatellite loci and mitochondrial control region sequencing. Current subspecific designations based on morphological traits were generally supported by these analyses, with the exception of the eastern (M. g. silvestris) and Florida (M. g. osceola) subspecies, which consistently formed a single unit. The Gould's subspecies was both the most genetically divergent and the least genetically diverse of the subspecies. These genetic patterns were consistent with current and historical patterns of habitat continuity. Merriam's populations showed a positive association between genetic and geographical distance, Rio Grande populations showed a weaker association and the eastern populations showed none, suggesting differing demographic forces at work in these subspecies. We recommend managing turkeys to maintain subspecies integrity, while recognizing the importance of maintaining regional population structure that may reflect important adaptive variation.