Morphological variation of Pinus flexilis (Pinaceae), a bird‐dispersed pine, across a range of elevations

Abstract

Limber pine (Pinus flexilis James) grows across a wider range of elevations than any other tree species in the central Rockies, from ∼1600 m at Pawnee Buttes to >3300 m at Rollins Pass. In this study we investigated two possible explanations for limber pine's success across a broad range of elevations: (1) the sites on which it is found, although separated by >1000 m elevation, may not be very different with respect to environmental factors that affect tree growth, and (2) limber pine growth is insensitive to environmental factors that change with elevation. We compared site characteristics of 12 limber pine stands at elevations ranging from 1630 to 3328 m as well as the growth and morphology of trees in each of these stands. Mean daily air temperature in July decreased linearly with the elevation of the site from 22.8° to 12.6°C. The growth and morphology of limber pine leaves, shoots, and trees were, in general, not related to the elevation or July mean air temperature of the sites. There was, however, a significant decrease in stomatal density with increasing elevation, which may be an acclimational response to restrict water loss at high elevations. Our data suggest that the fundamental and realized niche of limber pine is broad with respect to air temperature. In light of the high gene flow and only slight genetic differentiation among populations of species with bird-dispersed seeds, such as limber pine, it is especially unusual to see similar growth throughout an environmental gradient. Physiological and anatomical plasticity or wide physiological tolerance ranges may enable limber pine to uncouple its growth from its environment.

Adaptive variation in physiological traits of beech provenances in Central Europe

“…In our study, we try to determine levels of adaptation of beech provenances to climate conditions at the trial site in relation to the climate of origin. Several recent studies have focused on the suitability of environmental conditions at different altitude ranges of plant species (Schoettle & Rochelle 2000, Holland & Richardson 2009 and also on the effect of stress factors differing among plots (Jägerbrand & Kudo 2016). The divergence between populations is driven by the differences in the selective pressure imposed by different ecological environments, neutral evolutionary processes or both (Still et al 2005); in our case, when the distances between the studied populations are quite large, the role of neutral factors such as isolation by distance or genetic drift may be important, but we tried to minimize such effects by choosing populations originating from the same glacial refugium (Slovenia/Istria - Magri et al 2006).…”

“…The increased stomatal density and stomatal size are considered to improve the plant efficiency of CO2 uptake. However, their decrease might reflect a decrease in the relative air humidity and hence it could be associated with plant water-saving strategy (Schoettle & Rochelle 2000, McElwain 2004.…”

Ecological types of the eastern slope of the Wind River Range, Shoshone National Forest, Wyoming

“…nutcracker might cache in one season are actually retrieved and consumed, leaving the remaining 20% to be eaten by rodents or germinate (Lanner and Vander Wall 1980;Schoettle and Rochelle 2000). Seedlings will commonly germinate in clusters from Clark's nutcracker seed caches, a phenomenon that often results in clumped or multi-stem growth habit (Steele 1990).…”

“…The Clark's nutcracker prefers to cache seeds in areas of low snow accumulation where snows melt earlier in the winter, including south-facing sites and windward slopes. About 80% of the approximately 20,000 to 30,000 seeds per ha that a single nutcracker might cache in one season are actually retrieved and consumed, leaving 20% to be eaten by rodents or germinate (Lanner and Vander Wall 1980;Schoettle and Rochelle 2000).…”

Options for the management of white pine blister rust in the Rocky Mountain Region

“…In the northern Rocky Mountains, limber pine generally occurs at lower elevations. In the Rocky Mountain Region, limber pine has a very wide elevational range, from the grassland-forest ecotone at 5,250 ft to the subalpine-alpine ecotone at 11,482 ft and everywhere in between (Schoettle and Rochelle 2000). Dave's Draw Research Natural Area on the Pawnee National Grassland contains one of the unique peripheral populations of limber pine.…”