Climate and seed availability initiate alternate post-fire trajectories in a lower subalpine forest

2016 ◽  
Vol 28 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Alexandra K. Urza ◽  
Jason S. Sibold
2014 ◽  
Vol 38 (6) ◽  
pp. 540-549 ◽  
Author(s):  
NI Xiang-Yin ◽  
◽  
YANG Wan-Qin ◽  
LI Han ◽  
XU Li-Ya ◽  
...  

1978 ◽  
Vol 56 (13) ◽  
pp. 1505-1509 ◽  
Author(s):  
Stephen A. Whipple

Species of buried, germinating seeds and species occurring in the vegetation are compared for two Colorado subalpine forest stands, one dry and one mesic, both over 325 years old. The total numbers of seeds found were small and the correspondence with species in the vegetation was poor. This is consistent with reports from other old-growth forests and may be accounted for by a combination of low seed input and rapid loss of viable seeds from the soil reservoir for old-growth forest species.


1980 ◽  
Vol 58 (15) ◽  
pp. 1704-1721 ◽  
Author(s):  
J. Bissett ◽  
D. Parkinson

The biomass, community composition, and metabolic activity of soil microorganisms were studied in adjacent burnt and unburnt areas of spruce–fir subalpine forest razed 6 years previously by a moderately severe natural fire. Similar levels of microbial biomass were observed at comparable burnt and unburnt sites, although the ratio of fungal to bacterial biomass was higher in the unburnt soils. The decreased acidity of the surface horizons in the burn probably tended to favor the development of a bacterial flora rather than a fungal flora. Microbial biomass in the burnt sites peaked earlier in the season than in the unburnt sites in response to the warmer soil temperatures and earlier thaw in the spring in the burn area.Significant differences in the species composition of the mycoflora in the organic soil horizons were observed between the burnt and unburnt sites. Apparently, these were related to qualitative differences in the recent litter. Phoma, Cladosporium, and Botrytis, which are usually associated with early stages of decomposition of herbaceous litter, were more common in the burnt soil. The mycoflora of the mineral soil horizons varied considerably from one burn site to another, possibly reflecting the geographical variation in the intensity of the burn. In overall composition, however, the mycoflora in the mineral soil horizons of the burn was not appreciably different from that of the unburnt sites.Higher laboratory rates of respiration and cellulose decomposition were observed for soil samples from the undisturbed forest. However, the rate of decomposition of cellulose in the field was much higher in the burnt sites, probably as a result of the higher soil temperatures in the burn area. Low soil temperature was concluded to be the main factor limiting microbial activities in the study area, and the removal of the insulating plant canopy and increased heat absorption by the ash in the burn area were found to increase decomposition rates, at least at this stage in the succession following the disturbance of fire.


2018 ◽  
Vol 41 ◽  
pp. 13-18
Author(s):  
Olav Hogstad ◽  
Tore Slagsvold

The Willow Tit Poecile montanus is highly sedentary and breeding pairs remain in their exclusive areas throughout the year. During the winter, these areas are defended by small, non-kin flocks, formed as the roaming yearlings become sedentary and join adults during late summer and autumn. Once established, stable social hierarchies are maintained in these flocks during the winter. The winter flocks consist normally of the socially dominant adult mated pair and two mated juvenile pairs, one higher-ranked and one lower-ranked. Individually colour-ringed juvenile Willow Tits were followed over years in subalpine forest in Norway from ringing in the autumn till they disappeared. None of the lower ranked birds survived their first winter, whereas only 4 of 71 higher-ranked juvenile pairs disappeared during this time. Half of the 71 pairs survived their first winter, about 25 % survived two winters, 8.5% survived three winters, and 5.6% survived four winters. Survival was similar for males and females. Alpha pairs remained mated and defended their common territory across years. Maximum age as revealed by ringing showed one female became six years old and two males ringed as adults were at least nine years old when last observed. The main factor associated with survival was early flock establishment that led to a high rank position among the juvenile flock members. Body size seemed insignificant. Birds that survived their first winter either succeeded to establish as territory owners or they were forced into the role as floaters and probably perished.


2016 ◽  
Vol 16 (1) ◽  
pp. 9
Author(s):  
Wayan Sudana

<p><strong>English</strong><br />Soybean consumption has grown rapidly, but its production increased at a much lower rate, and as a result its demand can only be met by import. On the other hand, the irrigated land most suitable for soybean development is still in a large potential. To utilize the resource, the government made a special effort through intensification and area expansion program as well. The irrigated lowland at West Java northern coastal region is one of strategic opportunities to boost soybean production based on location, accessibility and land suitability. Soybean is usually produced in the second dry season (July-September), and it is expected to increase farm income, to create rural employment opportunity especially for landless farmer. Some influencing factors for further development are among others good seed availability, irrigation and competition of labor used.</p><p> </p><p><strong>Indonesian</strong><br />Pertumbuhan konsumsi kedelai dari tahun ke tahun terus mengalami peningkatan, sehingga mengakibatkan ketidakseimbangan pertumbuhan konsumsi dan produksi kedelai dalam negeri. Untuk menutupi kekurangan konsumsi dalam negeri terpaksa dilakukan impor. Di lain pihak potensi lahan yang cocok untuk pengembangan kedelai ini masih cukup besar. Untuk memanfaatkan potensi sumberdaya lahan ini pemerintah berusaha melalui berbagai upaya khusus baik melalui intensifikasi maupun ekstensifikasi. Sawah irigasi teknis di Pantura Jawa Barat merupakan salahsatu peluang pengembangan kedelai yang sangat strategis bila dilihat dari letak, aksessibilitas dan kesesuaian bio-fisik lahan. Pengembangan kedelai di lahan ini pada MK II (Juli - September) disamping dapat meningkatkan penerimaan usahatani juga membuka peluang kesempatan kerja bagi buruhtani di pedesaan. Untuk pengembangan selanjutnya faktor yang perlu diperhatikan untuk menunjang keberhasilan program ini antara lain kelembagaan penyediaan benih bermutu, pengaturan air serta persaingan penggunaan tenaga kerja.</p>


2016 ◽  
Author(s):  
Scott Ferrenberg ◽  
Alexander S. Martinez ◽  
Akasha M. Faist

Background. Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods. Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species) and belowground (species active in organic and mineral soil layers) arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community) and modified Winkler funnels (belowground community) and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies diversity and assemblages. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models calculated from observed vs. expected levels of species turnover (Beta diversity) among samples. Results. Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the aboveground arthropod communities and vegetation and soil properties, but no significant association among belowground arthropod communities and environmental factors. Discussion. Our results suggest context-dependent influences of stochastic and deterministic community assembly processes across different fractions of a ground-dwelling arthropod community following a disturbance. This variation in assembly may be linked to contrasting ecological strategies and dispersal rates within above- and below-ground communities. Our findings add to a growing body of evidence indicating concurrent influences of different processes in community assembly, and highlight the need to consider potential variation across different fractions of biotic communities when testing community ecology theory.


2018 ◽  
Vol 11 (6) ◽  
pp. 781-785
Author(s):  
CM Oliveira Longa ◽  
D Francioli ◽  
M Gómez-Brandón ◽  
J Ascher-Jenull ◽  
T Bardelli ◽  
...  

1983 ◽  
Vol 28 (1-3) ◽  
pp. 231-248 ◽  
Author(s):  
Cynthia L. Burdick ◽  
Fiorenzo C. Ugolini ◽  
Robert J. Zasoski

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