Interior Populations Research Articles

Ecotypic differences and performance of the genetic resources of cocksfoot (Dactylis glomerata L.) in north‐west Spain

Quantitative traits and allozymes were used in two experiments to clarify the ecotypic differentiation of natural cocksfoot (Dactylis glomerata) populations from north‐west Spain. Thirty‐nine populations belonging to the four main ecotypes in Galicia were cultivated in two field experiments. In the first experiment, there were significant differences between ecotypes for heading date, flag leaf length, growth habit and vigour. Coastal populations were the least infected by rust. In the second experiment, allozyme markers presumed to be diagnostic for ssp. glomerata vs. izcoi (TO1 1·00, TO1 1·03) were found in all populations studied (ten tetraploids and one diploid izcoi). This suggests that gene flow occurs between coastal and interior populations. Culm and panicle lengths of tetraploids (without application of fertilizer) were inside the izcoi range in 1997, but some plants from all populations exceeded it in 1998. It is concluded that ssp. izcoi also occurs on the coast. Populations with a high level of complementary seasonal growth were detected.

HABITAT FRAGMENTATION AND DEMOGRAPHIC CHANGE FOR A COMMON PLANT: TRILLIUM IN OLD-GROWTH FOREST

I studied the influence of forest fragmentation on an understory herb, Trillium ovatum, in the Siskiyou Mountains of Oregon, where logging practices over the past 35 yr have created a mosaic of fragments surrounded by clearcuts and tree plantations. The age of trillium plants can be estimated by counting the annual constrictions on their rhizomes. Based on data collected by Whittaker in 1949 (i.e., pre-fragmentation) and a survey I conducted in 1995, I estimated that the process of clearcutting and subsequent conifer planting results in the mortality of almost all trillium (∼97.6%). In general, the remaining plants are not recruiting new individuals, even in sites clearcut 30 yr ago. Thus, trillium is restricted to smaller amounts of remnant, uncut forest. My study also demonstrated that populations in forest remnants that were within ∼65 m of forest-clearcut edges have had almost no recruitment of young plants since the time of the adjacent clearcutting, while forest interior populations contained higher recruitment levels. Projections based on these recruitment estimates indicated that edge populations will decline in size and interior populations will not decline. This study provides the first evidence of demographic changes in plant populations resulting from habitat fragmentation, and it offers evidence for the mechanisms responsible for such demographic changes.

ORIGIN AND DISTRIBUTION OF THE YEW BIG BUD MITE,CECIDOPHYOPSIS PSILASPIS(NALEPA), IN BRITISH COLUMBIA

AbstractThe distribution of the yew big bud mite,Cecidophyopsis psilaspis(Nalepa), a pest causing severe damage to Pacific yew,Taxus brevifoliaNutt., was determined within British Columbia. From 1992 to 1994, vegetative and reproductive buds on branch samples collected from 38 interior and 43 coastal populations of Pacific yew were examined for the occurrence of the mite. Mite damage was characterized by marked swelling and browning of both vegetative and reproductive buds. Interior Pacific yew populations were found to be mite free, whereas coastal yew populations were mite infested, except at three high-elevation (>700 m) coastal locations which were apparently mite free. At three other sites, individual trees without symptoms of mite attack did harbour low-density, nondamaging mite populations. The hypothesis that this mite is indigenous is less supported than the hypothesis that it was introduced to British Columbia on English yew,Taxus baccataL., and is limited to its present distribution by climatic and mountain barriers.

Fine Population Structure of Discula destructiva

Fifty-one isolates of Discula destructiva obtained from various Cornus species were evaluated using arbitrary signatures from amplification profiles (ASAP). ASAP analysis is based on dual-step arbitrary primer-based amplification procedure that produces “fingerprints of fingerprints” and in many instances increases detection of polymorphic DNA. This novel technique was able to distinguish groups of isolates from the northeast, middle and southeast range of the disease as well as western United States and Canada. The data supports the contention of recent and independent introduction of the disease on both east and west coasts, a genetic “bottleneck” that has limited diversity of the pathogen, and directionality of introduction of disease from coastal ports-of-entry to interior populations of C. florida and C. nuttalli.

Suriname: A Military and Its Auxiliaries

The official state military establishment of Suriname is small, numbering about 4,000 at its height in the mid-1980s. However, in order to consolidate their political power, sow terror, and gather intelligence, the military and its (then) left wing supporters augmented their forces with irregulars and auxiliaries. These were armed, funded, and coordinated by the military command, although not always answerable to them; such groups were variously called the People's Militia (Volksmilitie), and were patterned after the Cuban model. A terrorist strike force was established within the formal military ranks, and five civilian insurgent groups were created to advance military control over interior populations and territory. Suriname is a Caribbean country sharing generally in the political-economic legacies of plantation slavery that rendered Caribbean societies highly pluralistic and socially fragmented. For a desperate period in the 1980s the military had become the ultimate arbiter of power in a state that is still far from becoming a nation.

Changing Populations of Double-Crested Cormorants

-The Double-crested Cormorant (Phalacrocorax auritus) has a wider range in North America than any of the five other breeding cormorants and is the only species to occur extensively in the interior as well as on the coasts. Breeding birds are currently known in 40 of the 50 States of the United States, all 10 Canadian Provinces, and in Mexico, Cuba and the Bahamas. There are six more-or-less distinct populations, and five subspecies have been described but their significance is unclear because measurements overlap substantially and the distributions of crest characters are poorly known. Scattered archeological and historical accounts indicate that numbers in the Interior and Atlantic populations declined during the 19th century, and subsequent increases have been facilitated, but not fully explained, by dam-building and by declines in persecution. Numbers increased from the 1920s into the 1950s when pesticides had major impacts. The Interior populations fell to low points about 1970 and the Atlantic population ceased growing. The species was recognized as of Special Concern in several states during this period. For the past 20 years numbers have been increasing rapidly in most areas, although information on nonbreeding birds is very sparse. Particularly large increases are reported for the subspecies auritus, both the Interior population centered in the Canadian Prairie Provinces and Great Lakes (220,000 pairs) and the Atlantic population on the Northeast Coast (96,000 pairs). These birds migrate to winter in the South, chiefly in coastal areas from Texas to North Carolina, where there is considerable overlap of birds from diverse breeding areas. The numbers of the resident populations in Florida and the Caribbean comprising subspecies floridanus and heuretus (14,000 pairs) are poorly known and are probably declining. The status of the small population in Alaska (cincinatus) (3,000 pairs) is not known. On the West Coast (albociliatus) (31,000 pairs) the numbers in Canada and the United States are increasing rapidly, but the status of Mexican populations is unclear. The migrations of the populations in the Pacific are not well characterized.

Observations on habitat use and social organization of a huemul Hippocamelus bisulcus coastal population in Chile

Habitat use and social organization of a huemul Hippocamelus bisulcus coastal population was studied in a periglacial fjord of Chile during spring. Only interior populations of this endangered deer had been previously studied. Typical group size was 2·2, and adult males and females were observed associating only twice. All age-sex classes (except fawns) fed mostly on the perennial herb Gunnera magellanica. Adult males and juveniles primarily used periglacial grassland, and adult females mainly bluff habitat. Newborn fawns were seen only on bluffs. Adult females may be using bluffs during spring to minimize predation on their newborn offspring. Old-growth forest was not used during spring, but fecal pellet-group transects suggested that this habitat had been used during winter. Coastal populations have suffered less human impact than interior populations, but some coastal areas are likely to be affected by logging, and there is a demand for transplanting coastal deer to interior reserves. To ensure the species' long-term survival, a better understanding of the behavioural ecology of coastal populations is necessary before resource extraction and transplants occur.

Geographic size variation in rock pigeons,Columba livia

Abstract The rock pigeon Columba livia has a large Afro‐Eurasian distribution throughout which it shows significant variation in size. Individuals from the British Isles are of intermediate size, and those to the south and at eastern Mediterranean localities are smaller. East of Iraq, however, and extending through Pakistan to the Himalayas, sizes average from intermediate to decidedly large. Interior populations of the North African desert have small individuals, whether from low or high elevations. Current infraspecific taxonomy does not accurately reflect size variation.

Phenotypic variation in Yukon populations of subalpine fir

To clarify the taxonomy of subalpine fir (Abies lasiocarpa (Hook.) Nutt.) and its relationship to balsam fir (Abies balsamea (L.) Mill.), populations from Washington to Yukon Territory and east to northern Ontario were compared on the basis of cone and needle morphology. Variation at the northern extreme of subalpine fir's range was expressed primarily within populations and appears to have arisen from selection owing to local environmental pressures. Multivariate analyses indicated geographic differentiation of coastal and interior subalpine fir populations and an affinity between northern and interior subalpine fir populations. Palynological data as well as similarities between northern and southern interior populations suggest a common Rocky Mountain refugium for the northern and interior populations. These results, together with earlier studies, justify varietal status for subalpine fir populations occurring east of the Coast and Cascade mountains of Washington and British Columbia and extending eastward to the Rocky Mountain crest. The new name for this interior variety is Abies lasiocarpa (Hook.) Nutt. var bifolia (Murray) Palmer & Parker. Balsam fir populations were indistinguishable from interior subalpine fir populations on the basis of needle morphology but well differentiated from these and coastal populations in cone morphology, supporting continued recognition of these firs as separate species. Key words: Abies balsamea, Abies lasiocarpa, Abies lasiocarpa var. bifolia, balsam fir, phenotypic variation, subalpine fir, taxonomy.

Chloroplast DNA in Pinus monticola

Within-species variability of a restriction site in the chloroplast (cp) DNA in Pinus monticola has been surveyed. Frequencies of two variants of the cp genome are significantly different in interior versus coastal populations. Paternal inheritance of the cp genome predominates, though some individuals have both variants of the genome. The presence of heteroplasmic individuals indicates occasional biparental inheritance.

Nesting Chronology and Success of Bald Eagles in Southwest Yukon

Much information is now available on nesting success of bald eagles (Haliaeetus leucocephalus) over most of the species' breeding range. However, little is known about sparsely distributed interior populations in the far north. We carried out nesting surveys in southwest Yukon Territory in 1980, 1981, and 1982 along the route of a potential gas pipeline. This note describes nesting chronology and productivity of bald eagles in that area. All nests were associated with aquatic habitats, including the shorelines of large and medium sized lakes and rivers, or wetland complexes characterized by numerous small lakes, ponds, and meandering streams in close proximity. All nests were in trees in valley bottom locations between the 655 and 870 m elevations. The study area, about 10 km wide and 450 km long, roughly paralleled the Alaska Highway from White River (62°00'N; 140°30'W) to Teslin Lake (60°30'N; 133°00'W).

Dynamics of a grizzly bear population during a period of industrial resource extraction. I. Density and age–sex composition

The characteristics of a grizzly bear (Ursus arctos) population in southeastern British Columbia were studied between 1979 and 1986, a period of timber harvest, gas exploration, and outdoor recreation, including grizzly hunting. I investigated the hypothesis that collectively these activities were detrimental to the grizzly population. I predicted a low density of bears compared with other interior populations and (or) a negative rate of increase. The sex ratio of cubs and yearlings captured was 50:50 and they represented 21.5 and 17.5% of the population, respectively. Although more adult males than adult females were captured, I estimated that there were more adult females than males in the population. I used two methods of population estimation and assumed saturation trapping : one method was based on home range characteristics and the other on the proportion of aerial locations in the study area. The average estimated bear density was 6.4/100 km2, which was high for an interior population, and increased from approximately 5.7/100 km2 in 1981 to 8.0/100 km2 in 1986, for an average annual observed rate of increase of r = 0.07.

Some observations on the leaf oil terpene composition of mountain hemlock, Tsugamertensiana

The leaf oil terpene composition of mountain hemlock (sugamertensiana (Bong) Carr.) from eight central–coastal, three interior, and three southern populations was determined. High intra- but low inter-population variation was found. No significant elevational differences were recorded. Most trees from the southern populations had lower car-3-ene and higher α-pinene and β-phellandrene percentages than those from northern locations. Interior populations did not differ extensively from coastal populations. Owing to the high tree-to-tree variability, putative hybridization of mountain hemlock with western hemlock would be difficult to detect by leaf oil terpene analysis.

Chemosystematic study of Thuja plicata: Multivariate analysis of leaf oil terpene composition

Leaf oil terpene compositions from 55 western red cedar populations were analysed by discriminant and numerical analyses. The overall low intra- and interpopulational variability was confirmed, but small differences between coastal and interior populations were detected by canonical discriminant functions. There were also some minor differences between the populations from Vancouver Island and those near the Juan de Fuca Strait. No consistent correlations between northern and southern locations, elevation, or atypical morphology (branching), and terpene composition were found. Several outlier populations were indicated, but these were randomly distributed. It was concluded that discriminant analysis provided more detailed information than other treatments.

Chemosystematic studies in the genus Pinus. VI. General survey of the leaf oil terpene composition of lodgepole pine

The leaf terpene composition of 645 individual lodgepole pine trees and 79 bulked samples from 111 different sites or provenances and from one putative and three western jack pine populations (10 trees each) were analyzed by gas chromatography. Numerical analysis by a centroid cluster analysis of the mean squared Euclidean distances was carried out, and percentile distributions of the individual terpenes were plotted. The data obtained confirmed the previous subdivision into the major terpene pattern types A, B, and C (or H) and five subgroups (based on the high modes in bimodal distributions); four additional subgroups were added. Except for typical coastal populations, inter- and intra-populational terpene pattern variation was high. Centroid clustering and assignment of terpene types and subgroups lead to some distinct geographical groupings. Coastal populations (ssp. contorta) were found to be rather unifornm and only a minor difference appears to exist between northern and southern populations. Those near Haines, Alaska, the Skeena Valley, southeastern Vancouver Island, and the Puget Sound showed intermediacy with interior (ssp. latifolia) stands. The Fort Bragg (ssp. bolanderi) and Samoa populations from northern coastal California contained many trees with unique terpene patterns. The interior populations (ssp. latifolia) were highly variable and inverse frequencies of the type A (high near the coast) and type B (high in and near the Rocky Mountains) were recorded in several west-east transects. Introgression with jack pine, as measured by the frequency of type C/H patterns, was extensive in northeastern Alberta and the Peace River area of British Columbia. However, some difficulty in describing recent introgression was encountered. A unique (possibly archaic) population was encountered at Petitot River. The ssp. murrayana from the southern Cascades of Oregon and northern California could not be distinguished from ssp. latifolia further north by the terpenoid data.

A rangewide comparison of outlying and central lodgepole pine populations based on oleoresin monoterpene analysis

Monoterpene composition of the shoot cortical oleoresin from a number of centrally-located natural stands of Lodgepole pine was compared with that from populations derived from a variety of more peripheral parts of the natural range. The chemical diversity in interior populations was high; over much of the periphery it was much lower but locally in extreme north and north-eastern areas it became very high, a feature associated with possible glacial refugia and with recent introgressive influences from Jack pine. There is evidence for a more generally pervasive and probably more ancient interaction between, or progenitor of, the two species over a large part of the range, particularly in south-central British Columbia. The chemotypic distributional data are discusssd in relation to the recent history of the species.

Stomatal responses to humidity of coastal and interior populations of a Californian shrub.

Plants of two populations of Diplacus aurantiacus, a subshrub of the Californian chaparral, were compared for their stomatal response to water vapor concentration gradients. Plants of a coastal and an interior population were compared when grown under both low and high humidities. When grown at high humidity the coastal plants exhibited higher conductances and higher transpiration/photosynthesis ratios at all leaf-to-air water vapor concentration gradients than did the interior plants. Although all of the plants examined showed a pronounced stomatal response to humidity the response did not result in the degree of regulation of water-use efficiency reported for other Californian coastal species.

Biogeography of lodgepole pine

Lodgepole pine has been a component of the western North America flora throughout recent geological history although its present widespread distribution may be a relatively recent phenomenon (Late Pleistocene). The differentiation of populations within and between subspecies, and the distribution of rare alleles, both suggest that at the time of maximal Wisconsin glacial advance lodgepole pine was restricted to a number of refugia in the western United States, the islands along the north Pacific coast, and in an unglaciated region of the west-central Yukon. Subsequent to glacial retreat, lodgepole pine migrated to its present range with northern and southern interior populations meeting in northern British Columbia, possibly within the last 4000 years.

Comparison of Volatile Compounds and Stridulation Emitted by the Douglas-fir Beetle from Idaho and Western Oregon Populations 12

Volatile compounds were trapped from live Dendroctonus pseudotsugae from coastal (W. Oregon) and interior (Idaho) populations and analyzed by GC/MS. Two new compounds were partially characterized: pent-3-en-1-ol, found in all fed females, and 6- or 4-methylhept-5-en-2-one, identified from interior unfed males and fed females and from coastal females cross-fed in interior logs. In bioassay in Oregon, the trans isomer of the former compound increased aggregation of flying beetles to host compounds and to frontalin, and the 6-methyl isomer of methylheptenone effected 74% inhibition of flight aggregation. Fed Idaho females released a greater quantity of frontalin, but the ratio of pheromones was similar in the 2 populations. Unfed beetles from both populations released several monoterpenes, confirming a previous report. More β-pinene was released by interior than coastal females. Toothstrike rates of Idaho male stridulations were faster, as expected from the smaller size of interior beetles, but the general form and envelope of attractant, premating, and rivalry chirps were the same in the 2 populations. The release of methylheptenone by interior males and fed females, and greater amounts of frontalin and β-pinene by interior fed females are the most striking differences noted between the 2 populations studied; however, cross-feeding tests indicated that this difference is probably host-determined rather than genetic.

Populational variation in the leaf oil terpene composition of western red cedar, Thuja plicata

Intra- and inter-populational variations in the leaf oil terpene composition of western red cedar from 29 different collection sites from most of its natural range were investigated. This cedar species has one of the lowest degrees of variability found thus far in northern North American conifer species. No significant difference was found between coastal and interior populations and only slight divergence was recorded in outlying ones.