Oaks and the Biodiversity They Sustain (original) (raw)
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Diversity within Oaks. International Oaks 25: 57-70
In this paper an overview of the range of variations that occur in the genus Quercus (oaks) of the family Fagaceae is given. Oaks are one of the most important groups of flowering plants and dominate large regions of the Northern Hemisphere. We considered oaks from all regions of the world, while focusing on Himalayan oaks. These have not been studied as much by Western workers or by Indian botanists and foresters. With more than 600 species, Quercus is possibly the greatest natural ecosystem-forming genus of the world. Oaks are known for their great variety of growth forms, leaf shape and size, and for their nutrient-rich acorns. Many other trees might exceed the commercial value of oaks, but with regard to biodiversity, they have few parallels in the living world. Outside tropical rainforests, oaks are the greatest biodiversity-centric plants on the planet.
Himalayan broad-leaved forests are mainly dominated by oak (Quercus spp.) species. Oak species with other tree species provide numerous ecosystem services and serve as lifeline for local inhabitants. Overall tree diversity and their status in different oak dominated forests viz., Quercus leucotrichophora (1500-2200 m), Q. floribunda (2201-2700 m) and Q. semecarpifolia (2701-3300 m) were studied in Garhwal, Himalaya. A total of 54 tree species (40 genera) in Q. leucotrichophora, 43 tree species (30 genera) in Q. floribunda and 23 tree species (16 genera) in Q. semecarpifolia dominated forests were recorded. Lauraceae was the dominant family in Q. leucotrichophora and Q. floribunda forests (6 and 8 species respectively), while Ericaceae (3 species) was the dominant family in Q. semecarpifolia dominated forests. Pinaceae and Taxaceae were only two gymnospermic family represented by Pinus roxburghii at low, Abies pinrow at mid, Abies spectabilis and Taxus wallichiana at higher elevational oak forests. There was no significant variation (p=0.8) between overall tree density in different oak forests which ranges from 337±51 individual/ha in Q. semecarpifolia to 433±92 individual/ha in Q. leucotrichophora forests. The seedling density has significant variation (p=0.01) in different oak forests where highest density was recorded in Q. leucotrichophora forests (1981 individual/ha) and lowest in Q. semecarpifolia forests (348 individual/ha). The Total Basal Area (TBA) reported from Q. leucotrichophora (88.06 m2/ha) and Q. floribunda (110.5 m2/ha) forests was higher than those of earlier reported from the region, while basal area of Q. semecarpifolia (90.16 m2/ha) was comparable with the forests of western Himalaya.
An Ethno-Botanical Overview of Oak: A Multipurpose Wild Tree Species of the PirPanjal Himalayas
Oak is a very important tree species of the temperate broadleaved Himalayan forests. It is valued for a multitude of benefits reaped by the locals in the PirPanjal Himalayas. In the traditional agro-pastoral setup, the locals' socioeconomicengagementsgreatly rely on thistree. Quercus leucotrichophora and Q. floribunda are the two dominant species growing wild in the region. An attempt is made in the present study to investigate and expose the type and extent of the role played by this tree in the livelihoods of rural populations. Certain factors responsible for regular shrinkage of oak forests in the area have also been assessed briefly.
Structure and Floristic Composition of Oak Forests in Kandi Forest Range of District Rajouri
Journal of Bioresouces, 2019
The present study was conducted to explore the key phytosociological and diversity characteristics of Oak dominated forests (Kandi forest range) in Rajouri Forest Division of Jammu and Kashmir. The study area is dominated by three species of oak viz. Quercus leucotrichophora, Q. floribunda and Q. semecarpifolia and hosts a good deal of floral diversity including certain endemic species. Boxus wallichiana, Rhododendron arborium and Viburnum grandiflora are the main associate species. Density, dominance and species diversity was assessed in three localities each represented by twenty randomly laid 10×10m 2 quadrats. A total of 20 tree species were found growing in the area with Quercus leuchotrichophora dominating at all sites with highest density (975), frequency (100%), basal cover (133 m²/ha) and IVI (167.20). Total density ranges from 770 to 975 individuals/ha for trees and 225 to 405 for shrubs whereas the total basal area for trees lies between 88.84 and 133 m²/ha. Species richness and diversity indices slightly vary across the stands studied. Shannon-Wiener Index ranges between 0.93 to 1.99 for trees and 1.34 to 1.93 for shrubs. Simpson's diversity index varies from 0.70 to 0.93 for tress and 0.73 to 0.84 for shrubs. Margalef Index ranges between 0.74 to 1.88 for trees and 0.73 to 1.17 for shrubs; Menhenick's Index lies between 0.20 to 0.44 for trees and 0.33 to 0.41 for shrubs and Peilio's index ranges from 0.49 to 0.75 for trees and 0.92 to 1.92 for shrubs. The forests are under severe anthropogenic pressure and demand appropriate management and conservation measures.
OakEcol: A database of Oak-associated biodiversity within the UK
Data in Brief, 2019
Globally there is increasing concern about the decline in the health of oak Quercus trees. The impact of a decline in oak trees on associated biodiversity, species that utilize oak trees, is unknown. Here we collate a database of all known birds, bryophytes, fungi, invertebrates, lichens and mammals that use oak (Quercus petraea and Q. robur) in the UK. In total 2300 species are listed in the database. For each species we provide a level of association with oak, ranging from obligate (only found on oak) to cosmopolitan (found on a wide range of other tree species). Data on the ecology of each oak associated species was collated: part of tree used, use made of tree (feeding, roosting, breeding), age of tree, woodland type, tree form (coppice, pollarded, or natural growth form) and season when the tree was used. Data on use or otherwise by each of the 2300 species of 30 other tree species was also collated. A complete list of data sources is provided. For further insights into how this data can be used see Collapsing foundations: The ecology of the British oak, implications of its decline and mitigation
Journal of Asia-Pacific Biodiversity, 2016
Himalayan forests are dominated by different species of oaks (Quercus spp.) at different altitudes. These oaks are intimately linked with hill agriculture as they protect soil fertility, watershed, and local biodiversity. They also play an important role in maintaining ecosystem stability. This work was carried out to study the diversity and regeneration status of some oak forests in Garhwal Himalaya, India. A total of 18 tree species belonging to 16 genera and 12 families were reported from the study area. Species richness varied for trees (4e7), saplings (3e10), and seedlings (2e6). Seedling and sapling densities (Ind/ha) varied between 1,376 Ind/ha and 9,600 Ind/ha and 167 Ind/ha and 1,296 Ind/ha, respectively. Species diversity varied from 1.27 to 1.86 (trees), from 0.93 to 3.18 (saplings), and from 0.68 to 2.26 (seedlings). Total basal area (m 2 /ha) of trees and saplings was 2.2e87.07 m 2 /ha and 0.20e2.24 m 2 /ha, respectively, whereas that of seedlings varied from 299 cm 2 /ha to 8,177 cm 2 /ha. Maximum tree species (20e80%) had "good" regeneration. Quercus floribunda, the dominant tree species in the study area, showed "poor" regeneration, which is a matter of concern, and therefore, proper management and conservation strategies need to be developed for maintenance and sustainability of this oak species along with other tree species that show poor or no regeneration.
The composition of the arthropod fauna of the canopies of some species of oak (Quercus)
European Journal of Entomology, 2005
1. A study was made by knockdown sampling and branch clipping of the arthropod fauna of the canopy of two native oak species (Quercus robur and Q. petraea) and of two introduced species (Q. cerris and Q. ilex) in woods near Oxford, UK, and of two native species (Q. pubescens and Q. ilex) in southern France. Sampling was undertaken for five years in the UK and for four years in France. All the specimens from the UK, except Acarina, Collembola and Nematocera were identified to species or, occasionally, to morphotype. 2. In terms of overall numbers, species richness and biomass, the results for Q. robur and Q. petraea in the UK were very similar. Their samples contained over three times the biomass and nearly double the number of species compared with those from the introduced oak species (Q. cerris and Q. ilex). 3. The ordinal composition was very similar on Q. robur and Q. petraea, and that on Q. cerris showed closer concordance to the composition of these trees than to that of Q. ilex in the UK. The ordinal composition of the faunas of the two native oak species in France showed closer concordance to each other than to any of the oak species in the UK. The proportion of Psocoptera was much higher in the UK, and that of Thysanoptera was higher in France. 4. The guild composition in terms of numbers, species richness and biomass were closely correlated on Q. robur and Q. petraea, and on Q. robur in two different woods, which argues for an underlying determinism in the development of community structure. The guild composition on the introduced species (Q. cerris and Q. ilex) was most closely correlated when expressed as species richness. 5. The similarity of the guild composition on the oak species in the UK in terms of the actual species found was tested by a modified Sørensen's Index. This showed that the guilds could be ranked in the following order of decreasing similarity: epiphyte fauna, tourists, scavengers, phytophages, parasitoids-predators. 6. There were distinct seasonal patterns. In terms of species richness the values showed a general trend peaking in summer and early autumn, but biomass peaked in May on the native oak species, mainly due to Lepidopterous larvae. The ratio of prey to predator and parasitoid biomass had a distinct seasonal pattern, there being an excess of prey in May, but almost an equivalence throughout the rest of the season. This may reflect the high population of spiders in the late summer and autumn, which are likely to feed on tourists. Most classical ecosystem models do not allow for this latter important source of food that is not itself dependent on the communities' habitat. 7. The epiphyte dwelling guild (principally grazing Psocoptera) was a major component of the fauna in terms of numbers on the evergreen Q. ilex in UK. This has been reported for other studies of evergreen species in temperate climates.
Biodiversity in oak forests (Quercus castaneifolia and Quercus macranthera) in Ramsar, northern Iran
2014
The study was accomplished in pure and mixed stands of Quercus castaneifolia and Quercus macranthera in northern Iran. collection of the sample and study of the ecological factors including the seasons, spring, summer and autumn of the years 2009 and 2010 was conducted and the scientific name of the species, life forms and Chorology were recorded using the available resources. 186 species have been identified of 6 Pteridophytes families, 2 families from Gymnosperms and 52 families of Angiosperms (8 families from a Dicotyledone and 44 families of Monocotyledon). The maximum number of species was related to the flowing family: Asteraceae, Papilionaceae, Lamiaceae, Orchidaceae and Poaceae. Raunkiaer’s classification of Hemicryptophytes 49%, Cryptophytes 20%, Phanerophytes 19%, and 8% Therophytes, Chamaephytes 3 percent and 1 percent of Epiphytic species are allocated to the region. Chorology study area showed the highest value in zone of Europe-Siberia (the Caspian), with 41% belonging. The study of the list of endangered species showed one endangered species, 5 vulnerable species. 20 species were identified as lower risk. Lilium ledebourii was identified as a rare species with relatively wide distribution in different parts of the region.