scholarly journals The Effects of Native Shrub, Fencing, and Acorn Size on the Emergence of Contrasting Co-Occurring Oak in Mediterranean Grazed Areas

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 307
Author(s):  
Roberto Díaz-Hernández ◽  
José Luis Vicente Villardón ◽  
Carolina Martínez-Ruiz ◽  
Belén Fernández-Santos
Keyword(s):  
Seedling Emergence ◽  
Climatic Conditions ◽  
Livestock Farming ◽  
Shrub Species ◽  
Large Herbivores ◽  
Oak Woodlands ◽  
Quercus Species ◽  
Negative Effect ◽  
Acorn Size ◽  
Native Shrubs

Research Highlights: The regeneration of Quercus species is usually very difficult in many oak woodlands transformed by livestock farming. Some studies have reported that shrubs can facilitate regeneration. However, the strength of interaction may vary depending on, among other factors, the shrub species and the stress tolerance of the oak species. Moreover, further studies are necessary to clarify the relative importance of the two facilitation mechanisms in the same community. Background and Objectives: Cytisus multiflorus (L’Her.) Sweet is a predominant shrub species in the Mediterranean grazed open-oak-woodlands found in the central west of the Iberian Peninsula (bioclimatic limit) and is present with Quercus pyrenaica Willd and Quercus ilex subsp. ballota Samp trees. Thus, we assessed the effect of these native shrubs and acorn size, and the effect of excluding large herbivores, on the seedling emergence of two contrasting co-occurring Quercus species under a bioclimatic limit. Materials and Methods: A manipulative field experiment was carried out considering four treatments as a combination of shrubs (shrub/no-shrub) and fence (fenced/open) factors. A total of twenty plots, five replicates for each treatment were available. In each plot, 20 acorns were sown: 10 acorns (5 small and 5 large) for each Quercus species. Acorn emergence was recorded during the first four years following the sowing. Results: Seedling emergence took place mostly in the spring of the first year after sowing. The presence of shrub was the main significant factor and incremented the emergence of both Q. ilex and Q. pyrenaica. The effect of the fence depended on the Quercus species considered, improving only the emergence of Q. pyrenaica. A negative effect with the small acorns was detected but only for Q. pyrenaica. In all treatments, Q. ilex emerged more than Q. pyrenaica. Conclusions: C. multiflorus had a clear facilitative effect on the seedling emergence of Q. ilex and Q. pyrenaica, which was much greater than the physical effect that acorn size and excluding large herbivores had. As such, this native shrub may have a key role in oak regeneration in Mediterranean grazed areas. Furthermore, in these areas of contact between marcescent and sclerophyllous Quercus species, Q. ilex currently emerges more than Q. pyrenaica. This could be indicative of a shift towards more xeric climatic conditions, which could lead to a change in the dominant tree species in the future. However, this change could be modulated by the effects of native shrub and large herbivores.

scholarly journals Sea-ice induced growth decline in Arctic shrubs

2017 ◽  
Vol 13 (8) ◽  
pp. 20170122 ◽  
Author(s):  
Mads Forchhammer
Keyword(s):  
Sea Ice ◽  
Ring Width ◽  
Plant Productivity ◽  
Climatic Conditions ◽  
Arctic Sea Ice ◽  
Annual Growth ◽  
The Arctic ◽  
Growth Time ◽  
Sea Ice Extent ◽  
Negative Effect

Measures of increased tundra plant productivity have been associated with the accelerating retreat of the Arctic sea-ice. Emerging studies document opposite effects, advocating for a more complex relationship between the shrinking sea-ice and terrestrial plant productivity. I introduce an autoregressive plant growth model integrating effects of biological and climatic conditions for analysing individual ring-width growth time series. Using 128 specimens of Salix arctica , S. glauca and Betula nana sampled across Greenland to Svalbard, an overall negative effect of the retreating June sea-ice extent was found on the annual growth. The negative effect of the retreating June sea-ice was observed for younger individuals with large annual growth allocations and with little or no trade-off between previous and current year's growth.

Direct seeding of PinusSylvestris using microsite preparation and invigorated seed lots of different quality: 2-year results

1994 ◽  
Vol 24 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Hans Winsa ◽  
Urban Bergsten
Keyword(s):  
Seed Quality ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Mineral Soil ◽  
Direct Seeding ◽  
Growing Seasons ◽  
Humus Layer ◽  
Negative Effect ◽  
Mean Germination Time ◽  
Better Than

Direct seeding of Pinussylvestris L. is a regeneration method, with potential for development considering scarification, microsite preparation, seed invigoration, and seed quality. Three seed lots of different quality concerning seed weight, germination percent, and mean germination time were used on two sites in northern Sweden. Microsite preparation, 2 cm deep pyramidal indentations, of the mineral soil improved seedling emergence on the two sites by 48 and 62%, respectively, compared with seeding without preparation other than removal of the humus layer. Microsite preparation in combination with invigorated seed, i.e., seed incubated at 30% moisture content for 7 days at 15 °C, resulted in seedling emergence of about 85% for the highest and about 50% for the lowest seed quality at both sites. Noninvigorated seed, seeded without microsite preparation, reached about 55% for the highest and 22% at one and 43% at the other for the lowest seed quality. Without microsite preparation there was no, or a negative, effect of seed invigoration on seedling emergence. Seedling survival after the first winter improved significantly with better seed quality. Survival averaged 92 and 72% at the two sites, with frost heaving causing most mortality. Seedlings from invigorated and redried seed survived better than seedlings from untreated seed. Seedlings from the best seed quality had higher values in seedling height, about 35%, shoot length, about 60%, and needle length, about 30%, after two growing seasons than seedlings from lower seed qualities. Invigoration and microsite preparation had no effect on measured growth characteristics.

Effects of invasive knapweed (Centaurea stoebe subsp. micranthos) on a threatened native thistle (Cirsium pitcheri) vary with environment and life stage

Botany ◽  
2015 ◽  
Vol 93 (9) ◽  
pp. 543-558 ◽  
Author(s):  
Tatyana A. Rand ◽  
Svata M. Louda ◽  
Kate M. Bradley ◽  
Kimberly K. Crider
Keyword(s):  
Invasive Plant ◽  
Lake Michigan ◽  
Life Stage ◽  
Seedling Emergence ◽  
Native Plant ◽  
Endemic Plant ◽  
Centaurea Stoebe ◽  
Seed Addition ◽  
Negative Effect ◽  
Cirsium Pitcheri

We examined the type and magnitude of invasive plant (Centaurea stoebe subsp. micranthos (Gugler) Hayek) effects on the demographic parameters of a rare plant (Cirsium pitcheri Torr. & A.Gray), using two seed addition experiments with three treatments in two dune habitats — lakeshore linear dunes and high perched dunes on Lake Michigan, USA. Treatments were near Centaurea stoebe subsp. micranthos, near a native plant, or in the open. Seedling emergence, establishment, and juvenile survivorship were significantly higher on perched dunes, with higher surface soil moisture, than on lakeshore dunes. Treatment effects varied significantly with habitat and life stage. Seedling establishment decreased near Centaurea stoebe subsp. micranthos on lakeshore dunes, but increased near any neighbor on perched dunes. However, juvenile survival was significantly lower near Centaurea stoebe. subsp. micranthos in both habitats. The probability of reaching the adult flowering stage was much lower, and occurred later, for plants near Centaurea stoebe subsp. micranthos, especially on lakeshore dunes. Thus, Centaurea stoebe subsp. micranthos had a strong negative effect on establishment, survival, and flowering of Cirsium pitcheri, but interaction intensity varied with habitat and life stage. The results suggest that coupling seed addition with watering and invasive plant removal could bolster populations of this rare endemic plant.

scholarly journals Effect Of Agrotechnical Measures And Varieties On Seasonal Dynamics Of Tetranychus Urticae Koch (Acari, Trombidiformes, Tetranychidae) On High Tunnel-Cultivated Garden Strawberries

2015 ◽  
Vol 69 (1-2) ◽  
pp. 45-49
Author(s):  
Ineta Salmane
Keyword(s):  
Tetranychus Urticae ◽  
Air Temperature ◽  
Spider Mite ◽  
Seasonal Pattern ◽  
Plant Cover ◽  
Climatic Conditions ◽  
Early Season ◽  
High Tunnel ◽  
Negative Effect ◽  
Two Spotted Spider Mite

Abstract The aim of the present study was to determine the seasonal pattern of two-spotted spider mite Tetranychus urticae on strawberries cultivated in polythene-covered high tunnels in temperate climatic conditions. Various cultivars were used and the effect of modification of plant covering indices on abundance and incidence of these mites was also tested. The number of two-spotted spider mites was relatively low at the beginning of the vegetation season and started to increase when average air temperature rose above 20 to 25 °C. In the experiment two types of tunnels differing in additional plant cover were used. The maximum mite abundance did not significantly vary between varieties in tunnel 1 conditions, but it was significantly lower for variety 'Sonata' in tunnel 2 conditions. Mite numbers significantly declined after strawberry foliage mowing and removal of polythene cover. Mite development was prolonged in tunnel 1, where additional cover of plants was used and higher early season air temperature was recorded in comparison to tunnel 2. It was concluded that increase in early season temperature can increase two-spotted spider mite abundance and have a more negative effect on strawberry plants in respect of foliage damage by mites.

Seed-bank and seedling dynamics in Hyparrhenia hirta are influenced by herbicide application and mowing management

2012 ◽  
Vol 34 (2) ◽  
pp. 199 ◽  
Author(s):  
V. K. Chejara ◽  
P. Kristiansen ◽  
B. M. Sindel ◽  
R. D. B. Whalley ◽  
C. Nadolny
Keyword(s):  
Seed Bank ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Climatic Conditions ◽  
Control Treatment ◽  
Native Flora ◽  
Seedling Dynamics ◽  
Herbicide Treatments ◽  
Seedling Emergence And Survival

Hyparrhenia hirta (L.) Stapf (Coolatai grass) is a summer-active, C4 perennial tussock grass, native to southern Africa and the Mediterranean region, which has invaded areas of native flora in Australia in recent decades. Understanding its seed and seedling dynamics and how various management treatments (e.g. mowing, herbicide and no management) affect these may assist in identifying the conditions and management strategies required to limit its invasion. The population dynamics of H. hirta have not been comprehensively studied previously. A 2-year field experiment (December 2005–December 2007) was conducted to determine the seed-bank size, pattern of seedling emergence and survival of H. hirta seedlings at three sites in northern New South Wales, Australia, under three treatments: unmanaged (control), mowing and herbicide treatments. The density of H. hirta seeds in the soil at each experimental site under different treatments was measured in December 2005 at the start of the experiment, in December 2006 before the application of the second round of treatments and again at the end of the experiment in December 2007. Hyparrhenia hirta seedlings were assessed at monthly intervals in permanent quadrats (0.5 × 0.5 m) to determine seedling emergence and survival. Seedling emergence occurred on many occasions during the 2-year period of the experiment in each treatment and at all sites but the main seedling flushes were observed from mid summer to early autumn. In 2007, at all sites, seedling emergence declined by more than 90% on the mowing and herbicide treatments compared with the control treatment. Seedling survival was greater in the mowing and herbicide treatments than in the control treatment. The seedling cohorts emerging in winter had a lower survival. This study showed that H. hirta infestations have a large viable seed-bank (~3000 m–2), dependent on the level of infestation and climatic conditions, but that the seed-bank declines rapidly when seed addition is prevented. Some form of direct control of established H. hirta plants in combination with providing appropriate grazing management to encourage competition between grasses will assist in the control of H. hirta.

Emergence and survival of Populus tremula seedlings under varying moisture conditions

2003 ◽  
Vol 33 (11) ◽  
pp. 2081-2088 ◽  
Author(s):  
Tarja Latva-Karjanmaa ◽  
Leena Suvanto ◽  
Kari Leinonen ◽  
Hannu Rita
Keyword(s):  
Seedling Emergence ◽  
Populus Tremula ◽  
Sowing Time ◽  
Large Numbers ◽  
Seedling Emergence And Survival ◽  
Negative Effect ◽  
Sowing Experiment ◽  
Moisture Conditions ◽  
Root Suckers ◽  
Survival Of Seedlings

Aspen produces large numbers of seeds, even though it mainly reproduces asexually with root suckers. The aim of this study was to find out how different moisture conditions affect emergence and survival of Populus tremula L. seedlings. This was studied with a sowing experiment (totally randomized factorial design). There were altogether 10 blocks, each containing 16 microsites and three treatments (sowing time, watering, sowing shelter) replicated twice in each block. Seedlings emerged on 56% of microsites. Sowing time affected seedling emergence. Both the proportion of microsites with seedlings and the number of seedlings per microsite were lower after first than after second sowing, when the weather was rainier. Watering increased the number of seedlings per microsite, but the proportion of micro sites with at least one seedling was not affected. Sowing shelter had a negative effect on the seedling emergence, especially after second sowing. The survival of seedlings was low (10%) and strongly dependent on watering. The effect of block and its interactions with treatments indicated that seedling emergence and survival depended also on seedbed conditions. We conclude that sexual reproduction of aspen may occur in nature, but it is rare. The seeds also maintained their germinability longer than earlier observed.

Une régie de trois coupes chez le dactyle (Dactylis glomerata L.) en régions agricoles du Moyen-Nord de l'Est du Canada

1999 ◽  
Vol 79 (2) ◽  
pp. 231-238
Author(s):  
R. Drapeau
Keyword(s):  
Dry Matter ◽  
Dactylis Glomerata ◽  
Climatic Conditions ◽  
Dry Matter Yield ◽  
Eastern Canada ◽  
The Third ◽  
Negative Effect ◽  
Cutting Management ◽  
Dactylis Glomerata L ◽  
Heading Stage

Orchardgrass (Dactylis glomerata L.) has good winter survival in the mid-north agricultural areas of eastern Canada. There is no information on the cutting management to use after the first harvest of orchardgrass under these climatic conditions. The objective of this study was to determine the required interval between harvests following a first harvest at heading stage to optimise the productivity and maintain the persistence of orchardgrass. An interval of 35 d between harvests was sufficient to obtain annual yields of 4 to 6 tonnes of dry matter per hectare. An interval of 28 d between harvests had no negative effects on orchardgrass persistence under our climatic conditions. A second harvest taken 42 d after the first one often had a negative effect on the dry matter yield of the third harvest. Each time this occurred, we observed that the second harvest had been taken after 20 July. Heading dates varied among years. In addition to the growth stage at the first harvest, the date of occurrence of the heading stage should be considered so that the second harvest will be taken before 20 July. Consequently, if heading is delayed in spring, the interval between the first and second harvest must be reduced to take the second harvest before 20 July. Delaying the third harvest had a negative effect on the dry matter yield of the first harvest of the following production year. These results indicate that it is possible to take three harvests before September under the climatic conditions of the mid-north of eastern Canada without affecting the persistence of orchardgrass. Key words: Dactylis glomerata L., orchardgrass, cutting stage, cutting intervals, cutting management, yield

Long-term response of the mamane forest to feral herbivore management on Mauna Kea, Hawaii.

2012 ◽  
Vol 18 (2) ◽  
pp. 123 ◽  
Author(s):  
E Reddy ◽  
D H Van Vuren ◽  
P G Scowcroft ◽  
J B Kauffman ◽  
L Perry
Keyword(s):  
Native Species ◽  
Age Distribution ◽  
Forest Recovery ◽  
Native Plant ◽  
Native Plant Species ◽  
Rate Of Increase ◽  
Negative Effect ◽  
Native Shrubs ◽  
Term Response

Seven exclosure sites located on Mauna Kea, Hawaii and established in the 1960s and 70s were sampled to characterize long-term response of the mamane (Sophora chrysophylla) forest to protection from feral sheep grazing, and to assess impacts of non-native plant species and recurrent sheep presence on forest recovery. The forest provides essential habitat for an endangered bird, the palila (Loxoides bailleui). Vegetation was sampled inside exclosures during 1972–1976, 1998, and 2009, and also outside exclosures during 2009. Patterns of response varied among exclosures, but overall, mamane trees and native shrubs showed increasing cover between the 1970s and 1998, then a slowed rate of increase in cover or a decline between 1998 and 2009. Cover of native herbaceous vegetation showed variable trends between the 1970s and 1998, and then appeared to decline between 1998 and 2009. Mamane height class distributions inside exclosures indicated that recruitment was initially high but then declined as heights shifted toward larger size classes, and presumably an older age distribution. We found limited evidence of a negative effect of non-native species on forest regrowth, but the effect was not consistent over time or among sites. Recurrent sheep presence outside exclosures negatively affected mamane canopy density and perhaps tree density at all sites, and mamane condition at some sites. Our results indicate that the mamane forest has shown substantial regrowth inside exclosures at some sites, especially those protected the longest. However, these exclosures represent a small portion of the mamane forest. Sheep presence continues to impact mamane recovery outside exclosures, and thus habitat quality for the palila.

Rehabilitating Downy Brome (Bromus tectorum)–Invaded Shrublands Using Imazapic and Seeding with Native Shrubs

2011 ◽  
Vol 4 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Suzanne M. Owen ◽  
Carolyn Hull Sieg ◽  
Catherine A. Gehring
Keyword(s):  
Community Composition ◽  
Plant Community ◽  
Native Species ◽  
Developmental Stages ◽  
Growth Stages ◽  
Plant Community Composition ◽  
Downy Brome ◽  
Invasive Grass ◽  
Shrub Species ◽  
Native Shrubs

AbstractRehabilitation of downy brome–infested shrublands is challenging once this invasive grass dominates native communities. The effectiveness of imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty about the impacts of imazapic on native species. We used a before-after-control-impact (BACI) field experiment and greenhouse studies to (1) determine if imazapic herbicide applied at 132 g ai ha−1 (8 oz/ac−1) and seeding with two native shrub species (Wyoming big sagebrush [Artemisia tridentata] and Mexican cliffrose [Purshia mexicana]) reduced downy brome cover and promoted shrub establishment, (2) assess potential effects of imazapic on nontarget plant species and plant community composition, and (3) determine if imazapic affected downy brome or seeded shrub species when applied at different developmental stages. Seeding shrubs, alone, or in combination with imazapic application, did not significantly increase shrub density, possibly because of droughty conditions. In the field, imazapic reduced downy brome cover by 20% and nontarget forb cover by 25% and altered plant community composition the first year after treatment. Imazapic was lethal to downy brome at all growth stages in the greenhouse and reduced shrub germination by 50 to 80%, but older shrub seedlings were more tolerant of the herbicide. We conclude that a one-time application of imazapic combined with seeding shrubs was only slightly effective in rehabilitating areas with high downy brome and thatch cover and resulted in short-term impacts to nontarget species. These results highlight the need to treat downy brome infestations before they become too large. Also, removing thatch prior to treating with imazapic, although likely lethal to the native shrubs we studied, could increase the effectiveness of imazapic.

scholarly journals Alternatif Kanatlı Yetiştiriciliği: Beç Tavuğu Yetiştiriciliği

2015 ◽  
Vol 3 (10) ◽  
pp. 806
Author(s):  
Sezai Alkan ◽  
İsmail Durmuş
Keyword(s):  
Biological Control ◽  
Economic Efficiency ◽  
Environmental Conditions ◽  
Genetic Resource ◽  
Guinea Fowl ◽  
Climatic Conditions ◽  
Poultry Production ◽  
Livestock Farming ◽  
The World

Guinea fowl live on the Africa continent as wild and where used intensively family livestock farming in the rural. Although the homeland of the Africa continent, Guinea growing rapidly increasing in the World. Nowadays, Guinea fowl is an important alternative genetic resource can be used in organic livestock farming which developing quickly. Able to adapt to different climatic conditions, have an economic efficiency level in the don’t good environmental conditions and being resistant to diseases are the biggest advantages. Besides, Guinea fowl eats insects, ticks, worms, mouse and snakes, especially in the surrounding of the livestock farming in the rural it can be used for biological control of these pests easily. Because of these advantages, Guinea fowl has a potential for alternative poultry production in Turkey. In this review, importance and general characteristics of Guinea fowl are given.

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