Distribution of Armillaria luteobubalina and its Impact on Community Diversity and Structure in Eucalyptus wandoo Woodland of Southern Western Australia

1997 ◽  
Vol 45 (1) ◽  
pp. 151 ◽  
Author(s):  
B. L. Shearer ◽  
A. Byrne ◽  
M. Dillon ◽  
R. Buehrig
Keyword(s):  
Host Species ◽  
Basal Area ◽  
Plant Species Richness ◽  
Community Diversity ◽  
Survival Strategies ◽  
Annual Rainfall ◽  
Bare Ground ◽  
Pathogen Population ◽  
Disease Extension ◽  
Eucalyptus Wandoo

Armillaria luteobubalina Watling & Kile is causinghigh mortality in Eucalyptus wandoo Blakely woodland that receives low annual rainfall of 500–700 mm, and it is a significantdisturbance agent affecting community structure. Discrete disease centresranged from 0.01 ha to 8 ha in size (mean 1.2 ± s.e. 0.3 ha) and had adiscontinuous distribution within the woodland. For 38 disease centres, thetotal area infested was 46.25 ha. Infection caused death of overstorey polesand veterans creating disease centres of greatly reduced biomass. Thisreduction was reflected by a negative correlation between the mortality ofoverstorey and basal area and diameter at breast height over bark (DBH). Theaverage mortality of E. wandoo trees was 47% indisease centres of intermediate impact, compared with 66% for highimpact areas. Regeneration of the host species increased following diseaseexpression, as evidenced by: significantly greater understocking oflignotubers and saplings in disease centres than in non-infested woodland,less bare ground in disease centres than in non-infested woodland, and apositive correlation between the mortality of overstorey and live understorey.By contrast, plant species richness and diversity did not differ significantlybetween infested and non-infested woodland. The severity ofA. luteobubalina infection was not strongly related tosite factors. The rate of disease extension varied considerably between yearsduring the period 1986–1994 and averaged 2.04 ± s.e. 1.05 myr-1. Of the 26 host species recorded, 23% werefrom the Proteaceae followed by a smaller percentage from the Myrtaceae andPapilionaceae (15% each). The high impact ofA. luteobubalina in E. wandoowoodland reflects the high susceptibility of the dominant host to infectionand survival strategies of the pathogen population in the harsh woodlandenvironment.

scholarly journals Aboveground Biomass Stockpile of Trees in Vallanadu Blackbuck Sanctuary, Peninsular India

2021 ◽  
Vol 16 (3) ◽  
pp. 755-763
Author(s):  
M. Nagaraj M. Nagaraj ◽  
M. Udayakumar
Keyword(s):  
Aboveground Biomass ◽  
Tamil Nadu ◽  
Basal Area ◽  
Single Species ◽  
Forest Tree ◽  
Annual Rainfall ◽  
Dry Forests ◽  
Peninsular India ◽  
Tree Inventory ◽  
Individual Trees

A forest tree inventory study was conducted in Vallanadu Black buck sanctuary, Tuticorin. The current study was conducted to assess tree density, species richness, basal area (BA) and aboveground biomass (AGB) stockpile. The study area has been classified as Southern Thorn Forest (SFT). One hundred square plots (total area 1 ha), each 10m × 10m (100 m2 each) laid randomly across study area. All live trees with ≥5 cm diameter at breast height (DBH) measured at 137 cm above the ground. As the whole, 1335 individual trees ≥5cm DBH recorded. A total number of 18 species recorded from 14 genera and 11 families in study area. The family Mimosaceae has maximum number of species (7 species) followed by Rhamnaceae (2 species), while 9 families had just single species’ each. The total basal area recorded was 22.046 m2 ha-1, while, the mean wood density (WD) of trees estimated as 0.70±0.093 g cm-3. Total amount of 50.065 Mg ha-1 present in STF. The contribution of different species in terms of total AGB varied significantly. Commiphora berryi stocked 45.13% (22.588 Mg ha-1) of AGB followed by A. planifrons (23.31%, 11.669 Mg ha-1), A. mellifera (7.233%, 3.621 Mg ha-1), whereas remaining 15 species collectively stocked 24.327% (12.187 Mg ha-1) AGB. The STF had a large number of trees compared to some dry forests within Tamil Nadu. Southern Thorn Forest endowed with a moderate number of trees species. Aboveground biomass stockpile of trees is comparable with the range recorded from Indian dry forests. The study area experiences lesser mean annual rainfall and >6 months dry season. Further, endowed with short-bole and smaller leaved trees, hence stocked a relatively lesser AGB in trees.

The effects of partial cutting on forest plant communities of western hemlock – Sitka spruce stands in southeast Alaska

2001 ◽  
Vol 31 (12) ◽  
pp. 2067-2079 ◽  
Author(s):  
Robert L Deal
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Plant Community ◽  
Basal Area ◽  
Plant Species Richness ◽  
Plant Community Structure ◽  
Old Growth ◽  
Partial Cutting ◽  
Southeast Alaska ◽  
Clear Cutting

The effects of partial cutting on plant species richness, community structure, and several understory species that are important for deer forage were evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 12–96 years ago when 16–96% of the former stand basal area was removed. The species richness and community structure of understory plants were similar in uncut and partially cut plots. However, plots where more than 50% of the basal area was cut had a significantly different plant community structure. Species composition and abundance also appeared to be distinctly different between hemlock-dominated and spruce-dominated stands. Partial cutting did not significantly change abundance for most of the important forage species for deer. The similarity in plant community structure between partially cut and uncut old-growth stands may be related to forest stand structures. The heterogeneous stand structures that develop after partial cutting are more similar to old-growth stands than to the uniform young-growth stands that develop after stand replacing disturbances such as clear-cutting.

scholarly journals Plant Killing by Mutualistic Ants Increases the Density of Host Species Seedlings in the Dry Forest of Costa Rica

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Sabrina Amador-Vargas
Keyword(s):  
Costa Rica ◽  
Host Plant ◽  
Host Species ◽  
Host Plants ◽  
Dry Forest ◽  
Bare Ground ◽  
Additional Food ◽  
Acacia Ants ◽  
Acacia Collinsii ◽  
Pseudomyrmex Spinicola

Some species of plant-mutualistic ants kill the vegetation growing in the vicinities of their host plant, creating an area of bare ground (clearing). The reduced competition in the clearing may facilitate the establishment of host species sprouts (clones and seedlings), which in turn benefits the ants with additional food and shelter (“sprout-establishment hypothesis”). To test this hypothesis, the density and origin ofAcacia collinsiisprouts growing inside clearings and in the vicinities of acacia plants without clearings were compared. Also, to assess the pruning selectivity of acacia ants (Pseudomyrmex spinicola), seedlings were transplanted into clearings. The reaction of ants towards unrewarding acacia seedlings (without food and shelter) was also tested. The density of acacia sprouts growing inside clearings was almost twice that in the vicinities of host plants without clearings, and sprouts were inhabited by nestmates of the colony that made the clearing. Clones and seedlings were found in similar proportions in the clearings, and ants did not kill unrewarding acacia seedlings or seedlings unrelated to their host. The benefit reported here for the ants could be in conflict with the host plant, especially when the plant has rhizomal reproduction.

Forests of the ultramafic mount Giting-Giting, Sibuyan Island, the Philippines

1998 ◽  
Vol 55 (2) ◽  
pp. 295-316 ◽  
Author(s):  
J. Proctor ◽  
G. C. Argent ◽  
D. A. Madulid
Keyword(s):  
Basal Area ◽  
Tree Height ◽  
Structural Features ◽  
Montane Forest ◽  
The Philippines ◽  
Annual Rainfall ◽  
Low Concentrations ◽  
Notable Increase ◽  
Maximum Tree Height ◽  
High Representation

Mount Giting-Giting is an ultramafic mountain on Sibuyan Island, Romblon Province, Republic of the Philippines. It was studied along the Mayo's Peak Ridge which had rainforest from about 200m up to c. 1550m. The grassland and scrub vegetation from 1550m to the summit (2050m) of Giting-Giting was not explored. The mean annual rainfall at the base of the mountain was c.2100mm which included a dry season around February and March. There was a notable increase in wind speed with altitude and there was about one hurricane (called a cyclone in the Philippines) per year. Analyses showed that the soils are acid ( 4.4–5.5), and have relatively low concentrations of Olsen extractable phosphorus (0.22–2.07μg g−1), low exchangeable potassium (0.04–0.41mEq 100g−1), and relatively low (for ultramafic soils) Mg/Ca quotients (0.31–2.87) and exchangeable nickel (1.0-23.8μg g−1). Coupled plots (of 0.25 or 0.04ha) were studied at altitudes from 325m to 1540m. All trees ≥ 10cm dbh were enumerated and structural features of the trees and smaller plants were quantified. The forests were all of fairly small stature (maximum tree height 24m) but dense (up to 2180 trees ha−1 in Lower Montane Forest (LMF) and up to 880 ha−1 in Upper Montane Forest (UMF)). While different taxa could be readily recognized, specific determinations were often impossible from the mainly sterile specimens. The LMF was species rich with up to at least 111 species of tree (≥ 10cm dbh) per 0.25-ha plot. There was no family clearly dominant in the two lower plots at 325m and 385m (where the Dipterocarpaceae were probably reduced by logging). At 770m and 860m the Dipterocarpaceae accounted for 12.9% and 14.7% of the basal area respectively. There was a surprisingly high representation of the Sapotaceae (25.9% of the basal area) at 1240m. At 1540m, the Araucariaceae (Agathis sp.) dominated one plot (37.1% of the basal area) and the Myrtaceae the other (72.4%).

scholarly journals Linking community and disease ecology: the impact of biodiversity on pathogen transmission

2012 ◽  
Vol 367 (1604) ◽  
pp. 2807-2813 ◽  
Author(s):  
Benjamin Roche ◽  
Andrew P. Dobson ◽  
Jean-François Guégan ◽  
Pejman Rohani
Keyword(s):  
Host Species ◽  
Disease Ecology ◽  
Biodiversity Loss ◽  
Pathogen Transmission ◽  
Community Diversity ◽  
Ecological Interactions ◽  
Disease Emergence ◽  
Pathogen Dynamics ◽  
Wildlife Pathogens ◽  
The Impact

The increasing number of zoonotic diseases spilling over from a range of wild animal species represents a particular concern for public health, especially in light of the current dramatic trend of biodiversity loss. To understand the ecology of these multi-host pathogens and their response to environmental degradation and species extinctions, it is necessary to develop a theoretical framework that takes into account realistic community assemblages. Here, we present a multi-host species epidemiological model that includes empirically determined patterns of diversity and composition derived from community ecology studies. We use this framework to study the interaction between wildlife diversity and directly transmitted pathogen dynamics. First, we demonstrate that variability in community composition does not affect significantly the intensity of pathogen transmission. We also show that the consequences of community diversity can differentially impact the prevalence of pathogens and the number of infectious individuals. Finally, we show that ecological interactions among host species have a weaker influence on pathogen circulation than inter-species transmission rates. We conclude that integration of a community perspective to study wildlife pathogens is crucial, especially in the context of understanding and predicting infectious disease emergence events.

scholarly journals The influence of plant species richness on stress recovery of humans

Web Ecology ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 121-128 ◽  
Author(s):  
Petra Lindemann-Matthies ◽  
Diethart Matthies
Keyword(s):  
Blood Pressure ◽  
Species Richness ◽  
Plant Species ◽  
Landscape Management ◽  
Plant Species Richness ◽  
Stress Recovery ◽  
Intermediate Species ◽  
Bare Ground ◽  
Relaxation Period ◽  
Post Stress

Abstract. Natural sceneries or single plants may have positive influences on human health. Here we show that plant species richness can positively influence recovery from stress. Meadow-like arrays of different species richness (1, 16, 32, 64 species) were presented to visitors (n=171) of a popular park in Zurich, Switzerland (one array per participant). Participants' systolic blood pressure was measured twice: directly after they had been stressed and once again after a 2 min post-stress relaxation period during which they looked at one of either the meadow-like arrangements of plants in pots or at bare ground, shielded on three sides by a tent-like structure. The decrease in blood pressure was larger when respondents could view an arrangement of plants instead of ground without vegetation. Relaxation was strongest at intermediate species richness (32 species). Age, gender, and a person's attachment to nature did not influence relaxation. Our results indicate that species-rich vegetation may contribute to recovery from stress which should be considered in landscape management and planning.

Performance of Anthocephaluschinensis in Puerto Rico

1985 ◽  
Vol 15 (3) ◽  
pp. 577-585 ◽  
Author(s):  
Ariel E. Lugo ◽  
Julio Figueroa
Keyword(s):  
Puerto Rico ◽  
Growth Rates ◽  
Calcareous Soils ◽  
Basal Area ◽  
Annual Rainfall ◽  
Fast Growing ◽  
Single Tree ◽  
Basal Area Growth ◽  
Area Growth ◽  
The Tropics

The growth of kadam (Anthocephaluschinensis (Lam.) A. Rich. ex Walp.), a fast-growing Asiatic species, was studied under different soil and climatic conditions in Puerto Rico. Plantings included a 10-year-old line planting, a 12.5-year-old plantation, 12 localities with 20-year-old single tree plots, and 1 locality with four 52-year-old trees. Over 600 trees were measured in all. Growth rates were comparable to those of fast-growing species elsewhere in the tropics; e.g., the 12.5-year-old plantation had a volume growth of 27.8 m3•ha−1•year−1 (77% was merchantable wood), a basal area growth of 1.82 m2•ha−1•year−1, and a total aboveground biomass production of 11.5 t•ha−1•year−1. Trees grew well both in plantations and in lines under natural forest. The 20-year-old single tree plots averaged up to 1 m•year−1 in height growth and 53 cm2•year−1 in basal area growth. Highest rates were observed in localities with high annual rainfall (>2500 mm) and with phosphorus- and silt-rich soils of high bulk density and low pH. After 10 years, basal area growth of trees was fastest in volcanic deep clay locations, followed, in order, by trees on volcanic shallow loams, calcareous soils, and plutonic sandy loams. However, basal area growth during the first 5 years was fastest in the plutonic sandy loams and slowest in the calcareous soils. After 20 years, volcanic deep clay soils still supported the fastest basal area growth rate (about 100 cm2•year−1), while the other locations converged at about 30 cm2•year−1. Trees reached maximum height after 20 years (average, 19 m; maximum, 26.5 m). Kadam growth was limited by close spacings (below 2.5 × 2.5 m). Trees exhibited excellent form (ratio of diameter at 1.3 m to diameter at 4.9 m > 0.8). We found no evidence of pest or disease attacks on trees, but noted severe tapering and stem twist in localities having poor growth rates. Results underline the need for caution when making species adaptability assessments in the tropics with short-term (<10 years) data.

Lucerne, phalaris, and wallaby grass in short-term pasture phases in two eastern Australian wheatbelt environments. 1. Importance of initial perennial density on their persistence and recruitment, and on the presence of weeds

2007 ◽  
Vol 58 (2) ◽  
pp. 113 ◽  
Author(s):  
B. S. Dear ◽  
J. M. Virgona ◽  
G. A. Sandral ◽  
A. D. Swan ◽  
B. A. Orchard
Keyword(s):  
Plant Density ◽  
Seedling Recruitment ◽  
Initial Density ◽  
Basal Area ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Annual Rainfall ◽  
Curvilinear Relationship ◽  
Initial Population ◽  
South Wales

The influence of initial plant density on the changes in the populations of 3 perennial pasture species, lucerne (Medicago sativa L.), wallaby grass (Austrodanthonia richardsonii (Cashm.) H.P. Linder), and phalaris (Phalaris aquatica L.), over a 3-year pasture phase was examined in the wheatbelt of southern New South Wales. The perennials were sown at 5 rates in combination with subterranean clover (Trifolium subterraneum L.) at 2 locations, Kamarah [430 mm average annual rainfall (a.a.r.)] and Junee (550 mm a.a.r). The range in initial plant populations for lucerne, phalaris, and wallaby grass was 4–74, 8–94, and 2–20 plants/m2, respectively, at Kamarah and 11–120, 9–149, and 6–48 plants/m2 at Junee. When sown at higher densities, the density of lucerne and phalaris declined curvilinearly over the 3 years at both sites. At the 3 lower densities, phalaris populations remained constant at both sites. Lucerne, in contrast, declined over all densities at both sites except at the lowest density at the wetter site (Junee). The rate of decline in lucerne was negatively related (R2 = 0.75) to initial density at Junee, but not at Kamarah. The density of the native grass, wallaby grass, increased with time at both sites through seedling recruitment. The invasion of experimental plots by the summer weed Eragrostis cilianensis (All.) Vign. ex Janchen (stinkgrass) was restricted by lucerne and phalaris, with a negative curvilinear relationship between perennial density and E. cilianensis seedlings in both environments (R2 = 0.65–0.70). In contrast, wallaby grass was ineffective at suppressing E. cilianensis. By the third year, phalaris had significantly higher herbage yields in spring than lucerne and wallaby grass at both sites and phalaris yield was independent of density. Lucerne yields at this time increased with density only at the wetter site (R2 = 0.64), but wallaby grass yields responded to increasing density at both sites (R2 = 0.27–0.59). The experiment demonstrated that establishing higher initial perennial populations of lucerne and phalaris, which did not recruit during the experiment, will result in the maintenance of higher populations over the life of a 3–4 year pasture phase despite proportionally higher rates of plant loss. The size of the initial population was less critical for wallaby grass, which was able to increase in density through recruitment. High initial populations are likely to be an advantage for suppressing weeds in swards of perennial species with limited ability to increase their basal area, such as lucerne and wallaby grass, but will be less beneficial for species such as phalaris, which can compensate by greatly increasing its basal area at lower densities.

Field Resistance in Three Native Monocotyledon Species That Colonize Indigenous Sclerophyll Forest After Invasion by Phytophthora cinnamomi

1984 ◽  
Vol 32 (4) ◽  
pp. 339 ◽  
Author(s):  
D Phillips ◽  
G Weste
Keyword(s):  
Phytophthora Cinnamomi ◽  
Lateral Roots ◽  
Fungal Growth ◽  
Field Resistance ◽  
Root Production ◽  
Root Tip ◽  
Bare Ground ◽  
Rapid Reduction ◽  
Sclerophyll Forest ◽  
Disease Extension

Lepidosperma laterale (Cyperaceae), Gahnia radula (Cyperaceae) and Poa sieberana (Poaceae) colonize bare ground of dry sclerophyll forest after disease due to P. cinnamomi. To determine their resistance, plants grown in divided root boxes were inoculated with 150-200 zoospores of the pathogen. Infected roots ceased growth. In the small necrotic lesions produced, the pathogen remained viable and capable of providing a source of inoculum for disease extension. Fungal growth was usually limited to the lesion but in some cases a few hyphae were observed in adjacent tissue. Away from the lesion there was a rapid reduction of fungal material and of the associated cellular disintegration. Rates of root production and root growth were not stimulated by infection but uninfected lateral roots replaced the root tip in some plants; in others, a new root tip emerged from the necrotic zone, enabling the plant to outgrow the fungal attack.

Changes in faunal and vegetation communities along a soil calcium gradient in northern hardwood forests

2012 ◽  
Vol 42 (6) ◽  
pp. 1141-1152 ◽  
Author(s):  
Colin M. Beier ◽  
Anne M. Woods ◽  
Kenneth P. Hotopp ◽  
James P. Gibbs ◽  
Myron J. Mitchell ◽  
...  
Keyword(s):  
New York ◽  
Acidic Deposition ◽  
Basal Area ◽  
Hardwood Forests ◽  
Trophic Levels ◽  
Community Diversity ◽  
Northern Hardwood Forests ◽  
Northern Hardwood ◽  
Underlying Mechanisms ◽  
Increasing Trends

Depletion of Ca from forest soils due to acidic deposition has had potentially pervasive effects on forest communities, but these impacts remain largely unknown. Because snails, salamanders, and plants play essential roles in the Ca cycle of northern hardwood forests, we hypothesized that their community diversity, abundance, and structure would vary with differences in biotic Ca availability. To test this hypothesis, we sampled 12 upland hardwood forests representing a soil Ca gradient in the Adirondack Mountains, New York (USA), where chronic deposition has resulted in acidified soils but where areas of well-buffered soils remain Ca rich due to parent materials. Along the gradient of increasing soil [Ca2+], we observed increasing trends in snail community richness and abundance, live biomass of redback salamanders ( Plethodon cinereus (Green, 1818)), and canopy tree basal area. Salamander communities were dominated by mountain dusky salamanders ( Desmognathus ochrophaeus Cope, 1859) at Ca-poor sites and changed continuously along the Ca gradient to become dominated by redback salamanders at the Ca-rich sites. Several known calciphilic species of snails and plants were found only at the highest-Ca sites. Our results indicated that Ca availability, which is shaped by geology and acidic deposition inputs, influences northern hardwood forest ecosystems at multiple trophic levels, although the underlying mechanisms require further study.

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