scholarly journals Seasonal patterns of light availability and light use of broadleaf evergreens in a deciduous forest understory: Potential mechanisms for expansion

2013 ◽  
Vol 03 (02) ◽  
pp. 151-160 ◽  
Author(s):  
Sheri A. Shiflett ◽  
Julie C. Zinnert ◽  
Donald R. Young
Keyword(s):  
Deciduous Forest ◽  
Light Availability ◽  
Forest Understory ◽  
Seasonal Patterns

Seasonal patterns of the CO2 exchange characteristics of understory plants from a deciduous forest

1976 ◽  
Vol 54 (10) ◽  
pp. 1094-1103 ◽  
Author(s):  
R. J. Taylor ◽  
R. W. Pearcy
Keyword(s):  
Deciduous Forest ◽  
Dark Respiration ◽  
Co2 Exchange ◽  
Forest Understory ◽  
Seasonal Patterns ◽  
Canopy Closure ◽  
Canopy Development ◽  
Photosynthetic Rates ◽  
Light Intensities ◽  
Reduced Light

The seasonal patterns of CO2 exchange characteristics were determined for six deciduous forest understory species that differed substantially in time of photosynthetic activity with regard to the time of overstory canopy development. Species that were photosynthetically active only before overstory canopy development were characterized by high maximum light-saturated net photosynthetic rates and high leaf and mesophyll conductances. These early species were, however, active for only a relatively brief period of time. Species that were present during overstory canopy closure initially had moderate light-saturated net CO2 uptake rates that dropped markedly in response to the reduced light intensities after overstory canopy closure. All species present during the summer under the strongly reduced light intensities had low rates of light-saturated net CO2 uptake and low leaf and mesophyll conductances. These species, however, possessed low dark respiration rates which resulted in higher rates of net CO2 uptake at low light intensities than those of the early species. Light-saturated photosynthetic rates were correlated with ribulose-1,5-diphosphate (RuDP) carboxylase activities in mature but not in young expanding leaves.

scholarly journals Diversity of Odonata (Insecta) in Seasonal Deciduous Forest fragments in southern Brazil (state of Rio Grande do Sul), with a new record for the state and comments on the seasonal distribution of the species

2019 ◽  
Vol 19 (4) ◽  
Author(s):  
Mateus Marques Pires ◽  
Carla Bender Kotzian ◽  
Cleber Sganzerla ◽  
Gabriel Prass ◽  
Marina Schmidt Dalzochio ◽  
...  
Keyword(s):  
Deciduous Forest ◽  
Rio Grande ◽  
Seasonal Distribution ◽  
The State ◽  
Seasonal Patterns ◽  
Forest Fragments ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Farm Ponds ◽  
First Occurrence

Abstract: We present an Odonata (Insecta) check list of species occurring in a fragment of the Seasonal Deciduous Forest (Atlantic Forest biome) from the central region of the state of Rio Grande do Sul (RS), southern Brazil, along with a list of the odonate species recorded in this phytoecological region for the state. In addition, we provide comments on the seasonal distribution of the species occurring in the study area. Two streams and seven farm ponds located in the middle course of the Jacuí River basin were surveyed between December 2007 and February 2009. Overall, we recorded 49 species from 21 genera and six families. Argia serva Hagen in Selys, 1865 (Coenagrionidade) had its first occurrence record mentioned for the state, elevating to 183 the total number of Odonata species occurring in Rio Grande do Sul. The number of species recorded in the study area corresponds to ~26% of the known Odonata diversity in RS. Libellulidae was the most species-rich family (22 species, ~45% of the total), followed by Coenagrionidae (18 species, 37% of the total). The checklist for the Seasonal Deciduous Forest in RS indicated the occurrence of 83 species of Odonata in this phytoecological region (~45% of the known odonate species in the state). This elevated diversity could be related to the density of the vegetation structure. In the study area, 20 species were found in streams, and 45 in farm ponds. Species occurrence showed marked seasonal patterns in the study area, with 88% of the species recorded from summer to autumn, and no species detected in streams in the winter. Moreover, 70% of the species were recorded in either one or two seasons in farm ponds, while 65% occurred solely in one season in streams. This result indicates that the life cycle of Odonata in southern Brazil is strongly influenced by seasonal patterns in temperature.

Evaluating relationships among tree growth rate, shade tolerance, and browse tolerance following disturbance in an eastern deciduous forest

2009 ◽  
Vol 39 (12) ◽  
pp. 2460-2469 ◽  
Author(s):  
Lisa M. Krueger ◽  
Chris J. Peterson ◽  
Alejandro Royo ◽  
Walter P. Carson
Keyword(s):  
Forest Dynamics ◽  
Shade Tolerance ◽  
Deciduous Forest ◽  
Species Turnover ◽  
Light Availability ◽  
Woody Species ◽  
Plant Performance ◽  
Eastern Deciduous Forest ◽  
Interspecific Differences ◽  
The Impact

Interspecific differences in shade tolerance among woody species are considered a primary driving force underlying forest succession. However, variation in shade tolerance may be only one of many interspecific differences that cause species turnover. For example, tree species may differ in their sensitivity to herbivory. Nonetheless, existing conceptual models of forest dynamics rarely explicitly consider the impact of herbivores. We examined whether browsing by white-tailed deer ( Odocoileus virginianus Zimmermann) alters the relationship between light availability and plant performance. We monitored growth and survival for seedlings of six woody species over 2 years within six windthrow gaps and the nearby intact forest in the presence and absence of deer. Browsing decreased seedling growth for all species except beech ( Fagus grandifolia Ehrh.). More importantly, browsing altered growth rankings among species. Increased light availability enhanced growth for three species when excluded from deer, but browsing obscured these relationships. Browsing also reduced survival for three species; however, survival rankings did not significantly differ between herbivory treatments. Our results indicated that browsing and light availability operated simultaneously to influence plant growth within these forests. Thus, existing models of forest dynamics may make inaccurate predictions of the timing and composition of species reaching the canopy, unless they can account for how plant performance varies as a result of a variety of environmental factors, including herbivory.

Dung longevity influences the fate of endozoochorically dispersed seeds in forest ecosystems

Botany ◽  
2011 ◽  
Vol 89 (11) ◽  
pp. 779-785 ◽  
Author(s):  
Bogdan Jaroszewicz ◽  
Ewa Pirożnikow
Keyword(s):  
Plant Species ◽  
Deciduous Forest ◽  
Coniferous Forest ◽  
Light Availability ◽  
European Bison ◽  
Plant Establishment ◽  
Seed Content ◽  
Closed Canopy ◽  
Seedling Germination ◽  
Forest Habitats

Many studies show large discrepancies between the potential (studied in the greenhouse) and realized (studied in the field) effects of endozoochory. The influence of environmental conditions on the fate of endozoochorically dispersed seeds and subsequent plant establishment is still not well understood. We addressed this issue by studying the viable seed content of the dung of European bison ( Bison bonasus L.) by means of seedling germination in the greenhouse and in two forest habitats in Białowieża Primeval Forest. The number of seedlings and the number of plant species that emerged from 1 L of feces were positively correlated with dung longevity. Generative shoots were produced by plants only in coniferous forest. Their number was positively correlated with dung longevity and with light availability. Germination of seeds from bison feces was higher in coniferous forest than in deciduous forest but did not differ between open- and closed-canopy plots within the same habitat. We conclude that (i) seed germination and plant establishment after endozoochorous dispersal is influenced by dung longevity; (ii) the number of generative shoots produced by endozoochorously dispersed plants is influenced by dung longevity and light availability; (iii) seeds of some plant species, present in dung, stay viable for at least 3 years.

Effects of simulated post-harvest light availability and soil compaction on deciduous forest herbs

2002 ◽  
Vol 32 (10) ◽  
pp. 1753-1762 ◽  
Author(s):  
Christine J Small ◽  
Brian C McCarthy
Keyword(s):  
Soil Compaction ◽  
Deciduous Forest ◽  
Light Availability ◽  
Natural Disturbance ◽  
Deciduous Forests ◽  
Herbaceous Plant ◽  
Eastern Deciduous Forest ◽  
Forest Herbs ◽  
Successional Species ◽  
Eastern Deciduous Forests

To better understand the response of eastern deciduous forest herbs to microenvironmental changes associated with logging, the effects of experimental light and soil compaction treatments were examined in six herbaceous plant species characteristic of varying successional stages. We found severe growth reductions and increased mortality of Osmorhiza claytonii (Michx.) C.B. Clarke, a shade-tolerant forest perennial, when grown in full sun and greater soil compaction. Deeply shaded conditions, similar to those beneath regenerating forests, resulted in reduced growth of early successional species such as Galium aparine L., and Eupatorium rugosum Houtt. Growth of other species such as Geum canadense Jacq., and Elymus hystrix L. appeared to increase in the patchy, intermediate light treatment mimicking mature eastern deciduous forests. Soil compaction caused severe reductions in height and biomass of Eupatorium rugosum and O. claytonii, early- and late-successional species, respectively. While harvested stands experience relatively uniform light environments, canopy gaps and sunflecks in mature eastern deciduous forests create heterogeneous light environments often correlated with recruitment, growth, and diversity of understory herbs. Therefore, management approaches that minimize alteration of forest environments and mimic natural disturbance patterns may be important to the maintenance and regeneration of forest herbs.

scholarly journals Light alters the impacts of nitrogen and foliar pathogens on the performance of early successional tree seedlings

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11587
Author(s):  
Alexander Brown ◽  
Robert W. Heckman
Keyword(s):  
Fungal Pathogens ◽  
Nitrogen Availability ◽  
Light Availability ◽  
High Light ◽  
Plant Performance ◽  
Forest Understory ◽  
Light Limitation ◽  
Tree Seedlings ◽  
Low Light ◽  
Foliar Damage

Light limitation is a major driver of succession and an important determinant of the performance of shade-intolerant tree seedlings. Shade intolerance may result from a resource allocation strategy characterized by rapid growth and high metabolic costs, which may make shade-intolerant species particularly sensitive to nutrient limitation and pathogen pressure. In this study, we evaluated the degree to which nitrogen availability and fungal pathogen pressure interact to influence plant performance across different light environments. To test this, we manipulated nitrogen availability (high, low) and access by foliar fungal pathogens (sprayed with fungicide, unsprayed) to seedlings of the shade-intolerant tree, Liquidambar styraciflua, growing at low and high light availability, from forest understory to adjacent old field. Foliar fungal damage varied with light and nitrogen availability; in low light, increasing nitrogen availability tripled foliar damage, suggesting that increased nutrient availability in low light makes plants more susceptible to disease. Despite higher foliar damage under low light, spraying fungicide to exclude pathogens promoted 14% greater plant height only under high light conditions. Thus, although nitrogen availability and pathogen pressure each influenced aspects of plant performance, these effects were context dependent and overwhelmed by light limitation. This suggests that failure of shade-intolerant species to invade closed-canopy forest can be explained by light limitation alone.

Sex-ratio variation and the function of staminodes in Aralia nudicaulis1This article is part of a Special Issue entitled “Pollination biology research in Canada: Perspectives on a mutualism at different scales”.

Botany ◽  
2012 ◽  
Vol 90 (7) ◽  
pp. 575-585 ◽  
Author(s):  
Emony I.E. Nicholls ◽  
Marcel E. Dorken
Keyword(s):  
Life History ◽  
Scale Up ◽  
Light Availability ◽  
Reproductive Function ◽  
Positive Association ◽  
Population Level ◽  
Pollination Biology ◽  
Forest Understory ◽  
Pollen Receipt ◽  
Forested Ecosystems

Aralia nudicaulis L. is a clonal dioecious herb common to forested ecosystems in eastern North America. Across 15 sites, the frequency of female ramets ranged between 5% and 95%. This variation was used to examine hypotheses involving the life history and pollination biology of A. nudicaulis. Because female reproductive function is thought to incur greater resource costs than male function, we predicted that female ramets should (i) be more common where resources (and light in particular) are more abundant and (ii) have lower rates of survival than male ramets. However, there was (i) no significant association between light availability (measured as canopy closure) and female frequencies across sites and (ii) ramet ages were skewed towards older ages for females, not males. Female A. nudicaulis produce staminodes that render female inflorescences visually similar to male inflorescences. We experimentally manipulated the presence–absence of staminodes and found that pollen receipt by females without staminodes was substantially lower than for plants with intact staminodes. Finally, pollinators tend to prefer visiting male over female flowers. We were interested in evaluating whether such preferences might scale up to the population level, with higher pollinator abundances at male-dominated sites. However, we instead found a strong positive association between pollinator abundances and female frequencies. Although there is unlikely to be a causal relationship between them, the identification of a common variable underlying variation in female frequencies and pollinator abundances might reveal key insights into the factors regulating the life history and pollination of forest understory plants.

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