Seedling survival responses to irradiance are differentially influenced by low-water availability in four tree species of the Iberian cool temperate–Mediterranean ecotone

2006 ◽  
Vol 30 (3) ◽  
pp. 322-332 ◽  
Author(s):  
David Sánchez-Gómez ◽  
Miguel A. Zavala ◽  
Fernando Valladares
Keyword(s):  
Water Availability ◽  
Tree Species ◽  
Seedling Survival ◽  
Cool Temperate

scholarly journals Fire suppression and seed dispersal play critical roles in the establishment of tropical forest tree species in southeastern Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiro Fujita
Keyword(s):  
Seed Dispersal ◽  
Tree Species ◽  
Seedling Survival ◽  
Fire Suppression ◽  
Forest Tree ◽  
Tree Seedlings ◽  
Seedling Mortality ◽  
Forest Tree Species ◽  
Seed Deposition ◽  
Syzygium Guineense

AbstractThis study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in an Afrotropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum was monitored for 2.5 years at four different microsites in savannah woodland in Malawi (southeastern Africa) under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), Uapaca kirkiana (a woodland tree), and at a treeless site. The number of naturally established forest tree seedlings in the woodland was also counted. Additionally, S. guineense ssp. afromontanum seed deposition was monitored at the four microsites. Insect damage (9% of the total cause of mortality) and trampling by ungulates (1%) had limited impact on seedling survival in this area. Fire (43%) was found to be the most important cause of seedling mortality and fire induced mortality was especially high under U. kirkiana (74%) and at treeless site (51%). The rate was comparatively low under F. natalensis (4%) and B. floribunda (23%), where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. Consequently, seedling survival under F. natalensis and B. floribunda was higher compared with the other two microsites. The seedling survival rate was similar under F. natalensis (57%) and B. floribunda (59%). However, only a few S. guineense ssp. afromontanum seedlings naturally established under B. floribunda (25/285) whereas many seedlings established under F. natalensis (146/285). These findings indicate that the facilitative mechanism of fire suppression is not the only factor affecting establishment. The seed deposition investigation revealed that most of the seeds (85%) were deposited under F. natalensis. As such, these findings suggest that in addition to fire suppression, dispersal limitations also play a role in forest-savannah dynamics in this region, especially at the community level.

Spatial associations among major tree species in a cool-temperate forest community under heterogeneous topography and canopy conditions

2013 ◽  
Vol 55 (2) ◽  
pp. 261-275 ◽  
Author(s):  
Takeshi Torimaru ◽  
Shinji Akada ◽  
Kiyoshi Ishida ◽  
Shuichi Matsuda ◽  
Machiko Narita
Keyword(s):  
Tree Species ◽  
Temperate Forest ◽  
Forest Community ◽  
Spatial Associations ◽  
Cool Temperate ◽  
Cool Temperate Forest

The effect of water supply on tree seed germination and seedling survival in a tropical seasonal forest in Veracruz, Mexico

1991 ◽  
Vol 7 (1) ◽  
pp. 69-83 ◽  
Author(s):  
Dominique Blain ◽  
Martin Kellman
Keyword(s):  
Water Supply ◽  
Tree Species ◽  
Seedling Survival ◽  
Light Level ◽  
Water Retention Capacity ◽  
Wet Season ◽  
Retention Capacity ◽  
Large Fluctuations ◽  
Rainfall Patterns ◽  
Tropical Seasonal Forest

ABSTRACTIn Iropical seasonal forests, mass seedling death may incidentally occur early in the rainy season following untimely germination provoked by an isolated heavy rainfall. We hypothesized that, in a soil with little moisture retention capacity, irregular rainfall patterns would result in large fluctuations of water supply and, in the early wet season, drought episodes could cause seedling death. This hypothesis was tested in a seasonal tropical forest in Mexico where seedling density is low and the soil consists of almost pure sand with a low water retention capacity. Various patterns of simulated rainfall were applied in the forest to seeds and seedlings of three common tree species. Overall very little difference in germination and seedling survival was observed between the various rainfall treatments. The results showed that rainfall patterns and the soil texture may interact in a much more complex way than was initially hypothesized, and that water availability to seeds and seedlings is not necessarily predictable. The absence of seedlings of the three tree species might be better explained by high seed predation and low light level in the understorey.

Seed germination, hydrothermal time models and the effects of global warming on a threatened high Andean tree species

2012 ◽  
Vol 22 (4) ◽  
pp. 287-298 ◽  
Author(s):  
Edgar E. Gareca ◽  
Filip Vandelook ◽  
Milton Fernández ◽  
Martin Hermy ◽  
Olivier Honnay
Keyword(s):  
Global Warming ◽  
Seed Germination ◽  
Water Availability ◽  
Tree Species ◽  
Hydrothermal Time ◽  
Germination Process ◽  
Germination Characteristics ◽  
Wide Range ◽  
Maximum Temperatures ◽  
Insight Into

AbstractSeed germination is a crucial event in a plant's life cycle. Because temperature and water availability are important regulators of seed germination, this process will likely be influenced by global warming. Insight into the germination process under global warming is thus crucial, and requires the study of a wide range of water availability and temperature conditions. As hydrothermal time (HTT) models evaluate seed germination for any combination of water potential and temperature, they can be suitable to predict global warming effects on seed germination. We studied the germination characteristics of the high Andean endemic tree speciesPolylepis besseri(Rosaceae), using HTT models. We were especially interested in the potential effects of global warming on seed germination. Assembly of HTT models forP. besseriwas fairly straightforward due to the lack of a seed dormancy mechanism. The models allowed prediction ofPolylepisgermination under constant and alternating temperatures. Initially, a global warming induced increase in the field minimum and mean temperature will increaseP. besserigermination, but as maximum temperatures rise above the optimum temperature for the species, seed germination will become jeopardized. Effects of global warming on seed germination are currently considerably underexplored. HTT models prove to be useful tools to study a plant species' general germination characteristics, and how they may become affected under global warming. For the endemic mountain tree speciesP. besseri, we predict an increase, followed by a decrease of seed germination under global warming.

Light-dependent seedling survival and growth of four tree species in Costa Rican second-growth rain forests

2005 ◽  
Vol 21 (4) ◽  
pp. 383-395 ◽  
Author(s):  
Silvia Iriarte Vivar Balderrama ◽  
Robin L. Chazdon
Keyword(s):  
Tree Species ◽  
Seedling Survival ◽  
Light Availability ◽  
Light Transmittance ◽  
Growth Responses ◽  
Low Light ◽  
Growth Increments ◽  
Light Gradient ◽  
Second Growth ◽  
Survival And Growth

The dependence of tree seedling survival and growth on light availability was evaluated over 15 mo in three second-growth, wet forest stands (15–18 y old) in north-eastern Costa Rica. Seedlings of four canopy tree species (Dipteryx panamensis, Hyeronima alchorneoides, Virola koschnyi and Vochysia guatemalensis) were planted into four canopy treatments in three replicated stands and in a pasture site, spanning a nearly complete gradient of light availability. Survival and growth of all species increased in response to increasing light availability, but species differed in survival in shaded microsites (6–20% light transmittance) and in growth increments per light increase. Hyeronima showed the highest mortality at low light levels and the highest relative height growth increase per light increase. In contrast, Virola showed high survival at low and moderate light, but showed the lowest leaf area and above-ground biomass per light increase among all species. Dipteryx and Vochysia maintained relatively high rates of survival and growth across the entire light gradient. Hyeronima and Virola showed trade-offs between growth and survival responses to light, unlike Dipteryx and Vochysia. Differences among species in seedling survival at low light may be determined by a variety of physiological and morphological traits that may or may not be mechanistically linked to growth responses.

Testing pathogen host specificity: a reciprocal field experiment in two types of tropical forest on Hainan, China

2013 ◽  
Vol 29 (6) ◽  
pp. 541-549 ◽  
Author(s):  
Wen Zheng ◽  
He He ◽  
Lin Xiao ◽  
Shixiao Yu
Keyword(s):  
Seed Germination ◽  
Host Specificity ◽  
Tree Species ◽  
Rain Forest ◽  
Forest Type ◽  
Seedling Survival ◽  
Cloud Forest ◽  
Soil Pathogens ◽  
Montane Rain Forest ◽  
Adult Trees

Abstract:The Janzen–Connell hypothesis suggests that highly specific pathogens decrease seedling survival close to the parent plant; however, the underlying mechanism remains unclear. Here, we tested the host specificity of soil pathogens to germinating seeds of Cyclobalanopsis fleuryi and Cryptocarya chinensis in tropical montane rain forest and cloud forest on Hainan, south China. Rhizospheric soils surrounding eight adult trees per species were collected in each forest type and divided into five soil treatments: parent, fungicide-sterilized, autoclave-sterilized, Fusarium-added and Pythium-added soils. Surface-sterilized seeds were sown in each of the five soil treatments and grown in two forest types. The seed germination percentages were significantly higher in sterilized soils (C. fleuryi, 41.5%; C. chinensis, 29.4%) than in non-sterilized soils (C. fleuryi, 28.3%; C. chinensis, 17.1%) in montane rain forest. The seed germination percentages in rhizospheric soil of conspecific parent trees were significantly lower in montane rain forest (C. fleuryi, 17.3%; C. chinensis, 10.5%) than in cloud forest (C. fleuryi, 37.1%; C. chinensis, 21.1%). Our results also suggest that the level of pathogen activity in each tree species varies depending on the environment. Our results support the hypothesis that host-specific pathogens shape tree species composition by differentially affecting seed germination under different environmental conditions.

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