Quercus georgiana
M.A.Curtis
Pays · région · aire protégée · écorégion · biome
Chargement du graphe…
Indicateurs du réseau écologique
Comment lire ce graphe
Ce graphe représente les interactions écologiques documentées entre Quercus georgiana et d'autres espèces, à partir de la base GloBI (Global Biotic Interactions, agrégation mondiale de la littérature scientifique) — source principale, complétée par d'autres jeux de données d'interactions agrégés par Ontologia. Il faut le comprendre comme une carte du savoir documenté, pas une carte de la réalité écologique exhaustive.
Limites principales
- Incomplet. La majorité des interactions écologiques en milieu naturel n'ont jamais été publiées. Une espèce sans liens visibles n'est pas isolée — elle est probablement mal étudiée.
- Biais publication pharmaco-agronomique. La littérature des interactions est polarisée par les enjeux économiques et sanitaires : parasitism / pathogen sur-pondéré sur les mammifères (recherche zoonoses, vecteurs), herbivory sur-pondéré sur les insectes phytophages (entomologie agronomique). À l'inverse, mutualisms, commensalisms et interactions sol/microbiote sont sous-cités. Conseil de lecture : sur les hubs mammifères ou les insectes ravageurs de culture, lire les arêtes parasitism / herbivory dominantes relativement au contexte de littérature, pas comme une mesure d'intensité écologique brute. Détails §10.1.
- Biaisé vers les espèces étudiées. Quelques espèces (oiseaux communs, abeille mellifère, espèces modèles) concentrent disproportionnellement plus d'interactions documentées. Notre score composite ajoute un malus aux hubs de littérature pour atténuer cette dominance visuelle.
- Interactions documentées globalement. Toutes les espèces affichées sont observées en France métropolitaine (les observations sont filtrées sur le territoire métropolitain), mais les interactions entre elles proviennent de la littérature scientifique mondiale. Une interaction documentée à l'étranger peut ne pas se réaliser à l'identique sur votre territoire. Le filtre « restreindre à ma commune » tient compte de la co-occurrence spatiale locale mais ne garantit pas l'interaction effective.
- Sans dimension temporelle. Les variations saisonnières (migration, floraison, cycle de vie) ne sont pas modélisées.
- Force d'interaction approximative. L'épaisseur des liens reflète le nombre de fois où l'interaction a été rapportée dans la littérature, pas son importance écologique réelle.
Comment nous sélectionnons les espèces affichées
Le graphe affiche au plus 31 nœuds par fiche (1 centre + 15 bulles depth=1 + 15 partenaires depth=2). Le serveur sélectionne intelligemment :
- Bulles famille créées si une cascade taxonomique existe ou si ≥3 espèces directement documentées partagent une même famille — les espèces sont absorbées dans la bulle (pas de doublon visuel)
- Espèces individuelles uniquement quand <3 dans une famille (sans cascade) — relations directes documentées
- Pas d'espèces inférées affichées en doublon — les cascades sont représentées via les bulles famille uniquement
- Partenaires depth=2 sélectionnés via algo priorité : candidat partagé par ≥2 docs de la famille (food web central) → reliant entre bulles → top sum_obs en dernier recours
- Sous-types GloBI traduits en français au survol de la flèche (chasse, parasite, parasitoïde, mycorhize…)
Le toggle Profondeur 1 ↔ 2 client-side cache ou affiche les partenaires depth=2 sans refetch. Filtres règne, type d'interaction, ordres/familles, patrimoniales et commune recalculent côté serveur (slow path live ~1-2 s).
Indicateurs avancés (mode expert) : Modularité Q (Newman 2006, PNAS), communautés (Louvain, Blondel et al. 2008, J. Stat. Mech.), nestedness NODF (Almeida-Neto et al. 2008, Oikos).
Source : GloBI · TAXREF v18 (INPN/MNHN) · BDC-Statuts · Wikidata
13 partenaires écologiques documentés directement dans GloBI.
Partenaires
13
Espèces avec interactions documentées
Types d'interactions
4
Prédation, pollinisation, parasitisme…
Connectance
0.078
Densité des liens dans le sous-graphe affiché
Rang plantae
76 %
Percentile vs ensemble des plantae
Liste rouge IUCN
EN · En dangercritères B2ab(i,ii,iii,iv,v)↘Décroissante- Évaluation
- 2015 · v3.1
- Altitude
- 50 – 500 m
- Profondeur
- – m
État de la populationTexte officiel évaluation IUCNExpert
Quercus georgiana is documented from 14 counties in Georgia, three in Alabama and historically from South Carolina and North Carolina.
The type locality of this species, located at Stone Mountain, DeKalb County, Georgia, is the best-documented and probably the largest occurrence. Another well-documented occurrence, located on Pine Mountain, Harris Co., Georgia, was observed to be relatively large and healthy in the late 1980s (R. Lance and M. Westwood pers. comm. 2015). Houle and Delwaide (1991) observed that Q. georgiana was often the second most frequent and abundant woody species on soil islands on Arabia Mountain, DeKalb Co., Georgia, in addition to noting a high proportion of juvenile trees (seedlings and saplings), suggesting successful reproduction was occurring at that time.
Occurrences in South Carolina are believed to be extirpated, and the single known occurrence in North Carolina, first documented in 2011, is reported to contain too few individuals to be considered viable (i.e., fewer than ten). Additionally, the North Carolina stand shows a high level of putative hybridization, likely due to introgression by other, more common Red Oak species in the vicinity. Therefore, for the purposes of maintaining the true genetic identity of the species, this subpopulation should be considered eradicated (R. Lance and M. Westwood pers. comm. 2015).
Throughout its restricted range, occurrences of Q. georgiana are small and geographically isolated. However, despite the geographic distance between occurrences, a recent molecular analysis of the species' genetic diversity revealed evidence of gene flow and low genetic isolation between subpopulations, suggesting these occurrences are not genetically isolated enough to be considered severely fragmented (Toppila 2012). The report did note, though, that this apparent gene flow could be a relict of past interconnectedness, and negative consequences of fragmentation may still remain to be seen. This study sampled approximately 25 individual trees each from nine occurrences in Georgia and Alabama (suggesting the population size is at least greater than 225 individuals). Notably, two subpopulations in Georgia were not sampled because trees were infrequent or not positively identifiable, indicating that these occurrences may be declining and/or suffering from introgression.
The type locality of this species, located at Stone Mountain, DeKalb County, Georgia, is the best-documented and probably the largest occurrence. Another well-documented occurrence, located on Pine Mountain, Harris Co., Georgia, was observed to be relatively large and healthy in the late 1980s (R. Lance and M. Westwood pers. comm. 2015). Houle and Delwaide (1991) observed that Q. georgiana was often the second most frequent and abundant woody species on soil islands on Arabia Mountain, DeKalb Co., Georgia, in addition to noting a high proportion of juvenile trees (seedlings and saplings), suggesting successful reproduction was occurring at that time.
Occurrences in South Carolina are believed to be extirpated, and the single known occurrence in North Carolina, first documented in 2011, is reported to contain too few individuals to be considered viable (i.e., fewer than ten). Additionally, the North Carolina stand shows a high level of putative hybridization, likely due to introgression by other, more common Red Oak species in the vicinity. Therefore, for the purposes of maintaining the true genetic identity of the species, this subpopulation should be considered eradicated (R. Lance and M. Westwood pers. comm. 2015).
Throughout its restricted range, occurrences of Q. georgiana are small and geographically isolated. However, despite the geographic distance between occurrences, a recent molecular analysis of the species' genetic diversity revealed evidence of gene flow and low genetic isolation between subpopulations, suggesting these occurrences are not genetically isolated enough to be considered severely fragmented (Toppila 2012). The report did note, though, that this apparent gene flow could be a relict of past interconnectedness, and negative consequences of fragmentation may still remain to be seen. This study sampled approximately 25 individual trees each from nine occurrences in Georgia and Alabama (suggesting the population size is at least greater than 225 individuals). Notably, two subpopulations in Georgia were not sampled because trees were infrequent or not positively identifiable, indicating that these occurrences may be declining and/or suffering from introgression.
Menaces identifiées(4 menaces classées CMP-IUCN)
6_1Recreational activitiesCausing/Could cause fluctuationsMinority (<50%)Ongoing11_1Habitat shifting & alterationUnknownMajority (50-90%)Future11_2DroughtsUnknownMajority (50-90%)Past, Likely to Return8_2_2Named speciesSlow, Significant DeclinesMinority (<50%)Ongoing
Description complète des menacesTexte détaillé évaluation IUCNExpert
Threats to Georgia Oak include erosion, poor regeneration and compacted soils resulting from foot and vehicle traffic on granite outcrops. Impacts of tourism and recreation are of concern, given that many occurrences lie within state parks and nature preserves, particularly at Stone Mountain where plants grow alongside popular hiking trails.
For occurrences with especially small numbers of individuals, genetic swamping and introgression from surrounding Red Oak species threaten the genetic identity of Quercus georgiana (R. Russell pers. comm. 2015, R. Lance and M. Westwood pers. comm. 2015).
Climate change may prove a serious threat to this species as well, given that Q. georgiana is confined to intermittent "soil islands" on granite outcrops, which have little or no connectivity to allow migration. Additionally, Q. georgiana displays many of the life history traits associated with vulnerability to climate change: limited dispersal ability, slow reproductive rates, specialized habitat requirements, and restricted distribution and rarity (Pacifici et al. 2015).
Drought also poses a considerable threat to Georgia Oak, given its restriction to very thin soils (50-100 cm in depth at some sites) on granite flat-rocks which provide little or no access to groundwater. Severe drought has been reported as an inciting factor in the phenomenon of oak decline, occurring when typically non-lethal stresses, such as drought, defoliating pests or fungal pathogens, are combined under certain conditions and effectively overwhelm oaks' defences, resulting in potentially widespread mortality (Bendixsen et al. 2015, Thomas et al. 2002). Additionally, many climate models project that climate change will contribute to dramatic increases in drought conditions in much of the United States, including the Southeast (Aiguo 2011). Recent severe drought events are already taking place, such as the drought that reached its peak in 2012, during which the entire extent of occupancy was considered to be affected, with much of this area experiencing Extreme or Exceptional drought intensity in late summer 2012 (Svoboda and the National Drought Mitigation Center 2012).
For occurrences with especially small numbers of individuals, genetic swamping and introgression from surrounding Red Oak species threaten the genetic identity of Quercus georgiana (R. Russell pers. comm. 2015, R. Lance and M. Westwood pers. comm. 2015).
Climate change may prove a serious threat to this species as well, given that Q. georgiana is confined to intermittent "soil islands" on granite outcrops, which have little or no connectivity to allow migration. Additionally, Q. georgiana displays many of the life history traits associated with vulnerability to climate change: limited dispersal ability, slow reproductive rates, specialized habitat requirements, and restricted distribution and rarity (Pacifici et al. 2015).
Drought also poses a considerable threat to Georgia Oak, given its restriction to very thin soils (50-100 cm in depth at some sites) on granite flat-rocks which provide little or no access to groundwater. Severe drought has been reported as an inciting factor in the phenomenon of oak decline, occurring when typically non-lethal stresses, such as drought, defoliating pests or fungal pathogens, are combined under certain conditions and effectively overwhelm oaks' defences, resulting in potentially widespread mortality (Bendixsen et al. 2015, Thomas et al. 2002). Additionally, many climate models project that climate change will contribute to dramatic increases in drought conditions in much of the United States, including the Southeast (Aiguo 2011). Recent severe drought events are already taking place, such as the drought that reached its peak in 2012, during which the entire extent of occupancy was considered to be affected, with much of this area experiencing Extreme or Exceptional drought intensity in late summer 2012 (Svoboda and the National Drought Mitigation Center 2012).
Habitats préférentiels (classification IUCN)
1_4Forest - Temperate6Rocky areas (eg. inland cliffs, mountain peaks)
Mesures de conservation recommandéesStratégies de conservation IUCNExpert
Quercus georgiana is considered Vulnerable (G3) by NatureServe, and is a focus of ongoing research and ex situ conservation efforts.
Kramer and Pence (2012) highlighted the successful in vitro propagation of Q. georgiana and the potential of cryopreservation as a conservation option for recalcitrant species, which cannot be stored in seed banks, such as oaks.
A recent study found that living collections of Georgia Oak exist in 30 institutions around the world, with 50% of accessions from known wild provenance (Toppila 2012). However, these accessions were found to be collected from only two subpopulations (Stone Mountain and Pine Mountain), indicating that future efforts should focus on collecting from other, more distant subpopulations in order to capture genetic diversity from across the species' range.
A research project is currently underway by scientists at The Morton Arboretum and Chicago Botanic Garden to further examine the genetic diversity of Q. georgiana trees, both in its natural stands and those in cultivated collections, which will help inform and guide future conservation efforts.
Kramer and Pence (2012) highlighted the successful in vitro propagation of Q. georgiana and the potential of cryopreservation as a conservation option for recalcitrant species, which cannot be stored in seed banks, such as oaks.
A recent study found that living collections of Georgia Oak exist in 30 institutions around the world, with 50% of accessions from known wild provenance (Toppila 2012). However, these accessions were found to be collected from only two subpopulations (Stone Mountain and Pine Mountain), indicating that future efforts should focus on collecting from other, more distant subpopulations in order to capture genetic diversity from across the species' range.
A research project is currently underway by scientists at The Morton Arboretum and Chicago Botanic Garden to further examine the genetic diversity of Q. georgiana trees, both in its natural stands and those in cultivated collections, which will help inform and guide future conservation efforts.
Actions de conservation (2)Conservation Actions Classification Scheme — IUCNExpert
1_1Site/area protection3_4_1Captive breeding/artificial propagation
Stress écologiques (8)Stresses Classification — IUCNExpert
1_2Ecosystem degradation1_2Ecosystem degradation1_3Indirect ecosystem effects1_3Indirect ecosystem effects2_1Species mortality2_2Species disturbance2_3_1Hybridisation2_3_8Other
Usage & commerce (1)Use & Trade — IUCNExpert
13Pets/display animals, horticulturenational
Priorités de recherche (4)Research Needed Classification — IUCNExpert
1_2Population size, distribution & trends1_5Threats3_1Population trends3_4Habitat trends
Niche IUCN globaleRealms · Systems · LMEs · Growth forms · FAOs — biogéographie IUCNExpert
Royaumes biogéographiques
Nearctic
Systèmes (terrestre/eau douce/marin)
Terrestrial
Formes de croissance
Tree - small
Références bibliographiques (15)Sources scientifiques de l'évaluation IUCNExpert
- IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015-4. Available at: <a href="www.iucnredlist.org">www.iucnredlist.org</a>. (Accessed: 19 November 2015).
- Lance, R. and Westwood, M. 2015. <i>pers. comm.: email conversation between Ronald Lance and Murphy Westwood, dated 15th-20th March 2015</i>.
- Bendixsen, D.P., Hallgren, S.W., and Frazier, A.E. 2015. Stress factors associated with forest decline in xeric oak forests of south-central United States. <i>Forest Ecology and Management</i> 347: 40-48.
- Pacifici, M., Foden, W.B., Visconti, P., Watson, J.E.M., Butchart, S.H.M., Kovacs, K.M., Scheffers, B.R., Hole, D.G., Martin, T.G., Akçakaya, H.R., Corlett, R.T., Huntley, B., Bickford, D., Carr, J.A., Hoffmann, A.A., Midgley, G.F., Pearce-Kelly, P., Pearson, R.G., Williams, S.E., Willis, S.G., Young, B. and Rondinini, R. 2015. Assessing species vulnerability to climate change. <i>Nature Climate Change</i> 5(March 2015): 215-225.
- GBIF. 2015. Global Biodiversity Information Facility (GBIF) Occurrence Download. Available at: <a href="http://www.gbif.org/">http://www.gbif.org/</a>. (Accessed: August 2015).
- Global Trees Campaign. 2014. <i>Georgia oak, </i>Quercus georgiana<i></i>. Fauna and Flora International and Botanic Gardens Conservation International, http://globaltrees.org/threatened-trees/trees/quercus-georgiana/.
- NatureServe. 2014. NatureServe Explorer: An online encyclopedia of life. [web application] Version 7.1. Arlington, Virginia Available at: <a href="http://www.natureserve.org">http://www.natureserve.org</a>. (Accessed: 3rd March 2015).
- Campbell, D. 2012. Noteworthy Collections: North Carolina. <i>Castanea</i> 77(1): 80-81.
- Toppila, R. 2012. Ex situ conservation of oak (<i>Quercus</i> L.) in botanic gardens: a North American perspective. University of Delaware.
- Svoboda, M. 2012. <i>U.S. Drought Monitor: Southeast, July 31st, 2012</i>. National Drought Mitigation Center, http://droughtmonitor.unl.edu/MapsAndData/MapArchive.aspx.
- Kramer, A.T. and Pence, V. 2012. The Challenges of Ex Situ Conservation for Threatened Oaks. <i>International Oak Journal</i>: 91-108.
- Aiguo, D. 2011. Drought under global warming: a review. <i>WIREs: Climate Change</i> 2: 45-65.
- Thomas, F.M., Blank, R., and Hartmann, G. 2002. Abiotic and biotic factors and their interactions as causes of oak decline in Central Europe. <i>Forest Pathology</i> 32: 277-307.
- Flora of North America Editorial Committee (FNA). 1997. <i>Flora of North America North of Mexico, Volume 3: Magnoliidae and Hamamelidae</i>. Oxford University Press, New York.
- Houle, G. and Delwaide, A. 1991. Population structure and growth-stress relationship of <i>Pinus taeda</i> in rock outcrop habitats. <i>Journal of Vegetation Science</i>: 47-58.
Évaluateurs & contributeurs (2)Personnes ayant contribué à l'évaluation IUCNExpert
assessor
Wenzell , K. & Kenny, L.
evaluator
Oldfield, S.
Wenzell , K. & Kenny, L. 2015. Quercus georgiana. The IUCN Red List of Threatened Species 2015: e.T34011A2840268. Accessed on 05 May 2026.
Répartition mondiale
Aucune observation géoréférencée avec précision suffisante (<10 km) dans GBIF pour cette espèce.