Alien mammals, impact and management in the french subantartic islands / J.L. Chapuis (1994)

Public ISBD Titre : Alien mammals, impact and management in the french subantartic islands Type de document : texte imprimé Auteurs : J.L. Chapuis ; P. Boussès ; G. Barnaud Editeur : Londres : Elsevier Science Année de publication : 1994 Collection : Biological Conservation num. 67 Importance : pp. 97-104., ill., graph., tabl., nb réf. Langues : Anglais (eng) Catégories : Autres descripteurs ALIEN MAMMALS ; ECOLOGICAL EFFECTS ; management ; FRENCH SUBANTARCTIC ISLANDS Résumé : The unique plant and animal communities of the French subantarctic islands have been greatly modified by the introduction of mammals since their discovery in 1552 and 1772. Nine species, wild and domestic, thrive due toa lack of competitors, predators and deseases and despite the small number of founders. Herbivores have induced significant changes to the nature and structure of plant communities and carnivores have modified burrowing petrel Procellaridae populations and species diversity. Introductions are now prohibited. Research programmes have been developed to study the population biology, and measures are being taken to control or eradicate alien species populations. Control programmes are effective for rabbits Oryctolagus cuniculus on the Kerguelen archipelago and cattle on Amsterdam Island. Planned programmes dseal with cat, mouflon and sheep in the Kerguelens. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=151426 Alien mammals, impact and management in the french subantartic islands [texte imprimé] / J.L. Chapuis ; P. Boussès ; G. Barnaud . - Londres (GB) : Elsevier Science, 1994 . - pp. 97-104., ill., graph., tabl., nb réf.. - (Biological Conservation; 67) . Langues : Anglais (eng) Catégories : Autres descripteurs ALIEN MAMMALS ; ECOLOGICAL EFFECTS ; management ; FRENCH SUBANTARCTIC ISLANDS Résumé : The unique plant and animal communities of the French subantarctic islands have been greatly modified by the introduction of mammals since their discovery in 1552 and 1772. Nine species, wild and domestic, thrive due toa lack of competitors, predators and deseases and despite the small number of founders. Herbivores have induced significant changes to the nature and structure of plant communities and carnivores have modified burrowing petrel Procellaridae populations and species diversity. Introductions are now prohibited. Research programmes have been developed to study the population biology, and measures are being taken to control or eradicate alien species populations. Control programmes are effective for rabbits Oryctolagus cuniculus on the Kerguelen archipelago and cattle on Amsterdam Island. Planned programmes dseal with cat, mouflon and sheep in the Kerguelens. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=151426

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Landscape scale variation in forest structure and biomass in a tropical rain forest / D.B. Clark (2000)

Public ISBD Titre : Landscape scale variation in forest structure and biomass in a tropical rain forest Type de document : texte imprimé Auteurs : D.B. Clark ; D.A. Clark Editeur : Londres : Elsevier Science Année de publication : 2000 Collection : Forest Ecology and Management num. 137 Importance : pp. 185-198., graph. tabl. nb réf. Langues : Anglais (eng) Catégories : Autres descripteurs TROPICAL RAIN FOREST ; LANDSCAPE ECOLOGY ; FOREST MESNURATION ; CARBON STOCKS ; EDAPHIC EFFECTS ; SOILS ; TOTPOGRAPHIC EFFECTS ; MESOSCALE LANDSCAPE Résumé : A better understanding of the reasons for variation in tropical rain forest (TRF) structure is important for quantifying global above-ground biomass (AGBM). We used three data sets to estimate stem number, basal area, and AGBM over a 600 ha old growth TRF landscape (La Selva, N.E., Costa Rica). We analyzed the effects of soil type, slope angle, topographic position, and different sample designs and measurement techniques on these estimates. All three data sets were for woody stems > 10 cm in diameter. Estimated AGBM was determined from stand level measurements using Brown's (Brown 1997) allometric equation for Tropical Wet Forest trees. One data set was from three subjectively sited 4 ha plots (the "OTS plots"), another was based on 1170 0.01 ha plots spaced on a regular grid (the "Vegetation map plots"), and the third was from 18 0.5 ha plots (the "Carbono plots ") sited to provide unbiased samples of three edaphic conditions : flat inceptisol old alluvial terraces ; flat ultisol hill tops; and steep ultisol slopes. Basal area, estimated AGBM and the contributions of major life forms were similar among studies, in spite of the differences in sampling design and measurement techniques. Althrough the Carbono plots on flat inceptisols had significantly larger and fewer trees than those on ultisols, AGBM did not vary over the relatively small edaphic gradient in upland areas at La Selva. On residual soils, the largest trees were on the flattest topographic positions. Slope angle per se was not correlated with basal area or AGBM within the residual soils. Errors introduced by palm and liana life forms, as well as hollow trees, did not significantly affect AGBM estimates. In contrast, the methods used to measure buttressed trees had a large impact. Plot sizes of 0.35-0.5 ha were sufficient to achieve coefficients of variation of ranged from 161 to 186 Mg/ha. These low values appear to be mainly due to the Tropical Wet Forest allometry equation used. This in turn may be indicative of a real and substantially lower ratio of biomass/basal area in Tropical Moist, as previously noted by Brown (1996). Our results indicate that for upland TRF landscapes with levels of environnement variation similar La Selva, AGBM will be relatively insensitive to soil type and topography. However, because topography and soil type had much stronger effects on stem size, stand density, and spatial heterogeneity of stems, stand dynamics may be more sensitive than AGBM to this range of conditions. We recommend that future studies of landscape scale forest structure employ stratified sampling designs across major environmental gradients. Unbiased sampling with replication, combined with consistent and well documented measurement techniques, will lead to a greatly improved inderstanding of the magnitude of and reasons for variation in forest structure and AGBM within TRF landscapes. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=151434 Landscape scale variation in forest structure and biomass in a tropical rain forest [texte imprimé] / D.B. Clark ; D.A. Clark . - Londres (GB) : Elsevier Science, 2000 . - pp. 185-198., graph. tabl. nb réf.. - (Forest Ecology and Management; 137) . Langues : Anglais (eng) Catégories : Autres descripteurs TROPICAL RAIN FOREST ; LANDSCAPE ECOLOGY ; FOREST MESNURATION ; CARBON STOCKS ; EDAPHIC EFFECTS ; SOILS ; TOTPOGRAPHIC EFFECTS ; MESOSCALE LANDSCAPE Résumé : A better understanding of the reasons for variation in tropical rain forest (TRF) structure is important for quantifying global above-ground biomass (AGBM). We used three data sets to estimate stem number, basal area, and AGBM over a 600 ha old growth TRF landscape (La Selva, N.E., Costa Rica). We analyzed the effects of soil type, slope angle, topographic position, and different sample designs and measurement techniques on these estimates. All three data sets were for woody stems > 10 cm in diameter. Estimated AGBM was determined from stand level measurements using Brown's (Brown 1997) allometric equation for Tropical Wet Forest trees. One data set was from three subjectively sited 4 ha plots (the "OTS plots"), another was based on 1170 0.01 ha plots spaced on a regular grid (the "Vegetation map plots"), and the third was from 18 0.5 ha plots (the "Carbono plots ") sited to provide unbiased samples of three edaphic conditions : flat inceptisol old alluvial terraces ; flat ultisol hill tops; and steep ultisol slopes. Basal area, estimated AGBM and the contributions of major life forms were similar among studies, in spite of the differences in sampling design and measurement techniques. Althrough the Carbono plots on flat inceptisols had significantly larger and fewer trees than those on ultisols, AGBM did not vary over the relatively small edaphic gradient in upland areas at La Selva. On residual soils, the largest trees were on the flattest topographic positions. Slope angle per se was not correlated with basal area or AGBM within the residual soils. Errors introduced by palm and liana life forms, as well as hollow trees, did not significantly affect AGBM estimates. In contrast, the methods used to measure buttressed trees had a large impact. Plot sizes of 0.35-0.5 ha were sufficient to achieve coefficients of variation of ranged from 161 to 186 Mg/ha. These low values appear to be mainly due to the Tropical Wet Forest allometry equation used. This in turn may be indicative of a real and substantially lower ratio of biomass/basal area in Tropical Moist, as previously noted by Brown (1996). Our results indicate that for upland TRF landscapes with levels of environnement variation similar La Selva, AGBM will be relatively insensitive to soil type and topography. However, because topography and soil type had much stronger effects on stem size, stand density, and spatial heterogeneity of stems, stand dynamics may be more sensitive than AGBM to this range of conditions. We recommend that future studies of landscape scale forest structure employ stratified sampling designs across major environmental gradients. Unbiased sampling with replication, combined with consistent and well documented measurement techniques, will lead to a greatly improved inderstanding of the magnitude of and reasons for variation in forest structure and AGBM within TRF landscapes. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=151434

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Modelling diameter increment in a lowland evergreen rain forest in French Guiana / S. Gourlet Fleury (2000)

Public ISBD Titre : Modelling diameter increment in a lowland evergreen rain forest in French Guiana Type de document : texte imprimé Auteurs : S. Gourlet Fleury ; François Houllier Editeur : Londres : Elsevier Science Année de publication : 2000 Collection : Forest Ecology and Management num. 131 Importance : pp. 269-389., ill. graph., tabl. nb réf. Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Forêt tropicale humide ; Guyane française Résumé : Since 1984, the diameter increment of nearly 50 000 trees > 10 cm DBH has been monitored every yea in 12 long-term experimental 6.25 ha plots of the Paracou experimental station, French Guiana. In order to study and compare forest dynamics in disturbed and indisturbed stands, contrasted silviculrural treatement were performed between 1986 and 1988 in these plots. Taking advantage of this experimental design and of this large database, a forest dynamics modelling project was started in 1992. This paper aims at presenting the growth component of the single tree, distance dependent model that was developed within the framework of this project. This individual diameter growth model was built according to the "potential x modifier" paradigm : it links tree annual diameter increment to variables describing tree size and instantancous competition as well as the recent past evolution of the competition. Species information was also taken into account and resulted : (i) in the classification of tree species into 15 functional groups that are homogeneous for diameter growth ; and (ii) in a definite improvement of model efficiency. Attempts to further reduce the residual through the use of soil and topographical information remained unsuccessful. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=151433 Modelling diameter increment in a lowland evergreen rain forest in French Guiana [texte imprimé] / S. Gourlet Fleury ; François Houllier . - Londres (GB) : Elsevier Science, 2000 . - pp. 269-389., ill. graph., tabl. nb réf.. - (Forest Ecology and Management; 131) . Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Forêt tropicale humide ; Guyane française Résumé : Since 1984, the diameter increment of nearly 50 000 trees > 10 cm DBH has been monitored every yea in 12 long-term experimental 6.25 ha plots of the Paracou experimental station, French Guiana. In order to study and compare forest dynamics in disturbed and indisturbed stands, contrasted silviculrural treatement were performed between 1986 and 1988 in these plots. Taking advantage of this experimental design and of this large database, a forest dynamics modelling project was started in 1992. This paper aims at presenting the growth component of the single tree, distance dependent model that was developed within the framework of this project. This individual diameter growth model was built according to the "potential x modifier" paradigm : it links tree annual diameter increment to variables describing tree size and instantancous competition as well as the recent past evolution of the competition. Species information was also taken into account and resulted : (i) in the classification of tree species into 15 functional groups that are homogeneous for diameter growth ; and (ii) in a definite improvement of model efficiency. Attempts to further reduce the residual through the use of soil and topographical information remained unsuccessful. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=151433

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