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No. de sistema: 000046543

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008 _ _ 110318m20119999ne^ur^p^^^^^^z0^^^a0eng^d
040 _ _ a| ECO
c| ECO
043 _ _ a| n-mx-cp
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245 0 0 a| Individual growth, reproduction and population dynamics of Dioon merolae (Zamiaceae) under different leaf harvest histories in Central Chiapas, Mexico
520 1 _ a| Leaves of the long-lived Dioon merolae have been harvested intensively for decades (possibly for centuries) for ceremonial purposes by Zoque and mestizo groups inhabiting the Central Depression of Chiapas, Mexico. Over a period of four years, we evaluated vital rates (stem growth, leaf production, reproductive performance, and survival) and projected population growth rates in three populations (250 plants each, divided into eight size classes: new germinants, seedlings, saplings (S1, S2), and adults, A1-A4) with different leaf harvesting histories: non-defoliated by humans for at least 55 years (or very old harvest), defoliated annually until 15 years ago (recovering from harvest), and defoliated annually for at least the past 25 years (currently being harvested intensely). Population structure was affected by leaf harvest history. Stem growth was negatively affected by the annual harvest of leaves in size classes from seedlings up to A4 (ANOVA, P < 0.003); fewer leaves were produced by seedlings, saplings and adults at the annually harvested site (ANOVA, P < 0.027). Survival was high at all sites across all size classes; in the annually harvested site, A4 plants showed a decrease in survival (one dead out of four plants). Sex ratio of adults that produced cones during the four years of study was 61% males to 39% females. At the non-defoliated site, adult classes A2 and A4 produced >80% of the cones; no cones were produced by the A3 and A4 adult size classes at the annually harvested site.
520 1 _ a| Asymptotic estimates of population growth indicated growing populations (λ≥1): the highest mean values of finite population growth rate were obtained in the non-harvested site (λ = 1.0202). Elasticity analysis with population projection matrices indicated that stasis (L, 9-38%) was the component that most contributed to λ, followed by growth (G, 1.2-2.9%), and fecundity (F, 0.2-1.1 %). We observed detrimental effects on several vital rates due to continued long-term defoliation, although population growth parameters do not currently suggest a decreased trend as a result of the annual harvest of leaves. The duration of this study of a very long-lived plant species suggests caution when setting levels and frequency of leaf harvest. The results help pinpoint practical recommendations that could be implemented in a sustainable management plan for this species, particularly to increase seed production in the annually harvested site, and recruitment of new germinants and seedlings at all sites. However, sound practices will need to consider the interests of involved stakeholders (landowners, pilgrims, conservation organizations and authorities) to effectively reduce anthropogenic pressure on this endangered species.
650 _ 4 a| Dioon merolae
650 _ 4 a| Defoliación
650 _ 4 a| Productos naturales no maderables
650 _ 4 a| Población vegetal
651 _ 4 a| Depresión Central (Chiapas, México)
700 1 _ a| Lázaro Zermeño, Julia Manuela
700 1 _ a| González Espinosa, Mario
d| 1950-
e| coaut.
700 1 _ a| Mendoza, Ana
e| coaut.
700 1 _ a| Martínez Ramos, Miguel
c| Doctor
e| coaut.
700 1 _ a| Quintana Ascencio, Pedro F.
d| 1959-
e| coaut.
773 0 _
t| Forest Ecology and Management
g| Vol. 261, no. 3 (2011), p. 427-439
x| 0378-1127
902 _ _ a| GOG/MM
904 _ _ a| Marzo 2011
905 _ _ a| Artecosur
905 _ _ a| Artfrosur
905 _ _ a| Biblioelectrónica
905 _ _ a| CRIIS
LNG eng
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Individual growth, reproduction and population dynamics of Dioon merolae (Zamiaceae) under different leaf harvest histories in Central Chiapas, Mexico
Lázaro Zermeño, Julia Manuela (autor)
González Espinosa, Mario, 1950- (autor)
Mendoza, Ana (autor)
Martínez Ramos, Miguel (autor)
Quintana Ascencio, Pedro F., 1959- (autor)
Contenido en: Forest Ecology and Management. Vol. 261, no. 3 (2011), p. 427-439. ISSN: 0378-1127
No. de sistema: 46543
Tipo: Artículo
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Inglés

"Leaves of the long-lived Dioon merolae have been harvested intensively for decades (possibly for centuries) for ceremonial purposes by Zoque and mestizo groups inhabiting the Central Depression of Chiapas, Mexico. Over a period of four years, we evaluated vital rates (stem growth, leaf production, reproductive performance, and survival) and projected population growth rates in three populations (250 plants each, divided into eight size classes: new germinants, seedlings, saplings (S1, S2), and adults, A1-A4) with different leaf harvesting histories: non-defoliated by humans for at least 55 years (or very old harvest), defoliated annually until 15 years ago (recovering from harvest), and defoliated annually for at least the past 25 years (currently being harvested intensely). Population structure was affected by leaf harvest history. Stem growth was negatively affected by the annual harvest of leaves in size classes from seedlings up to A4 (ANOVA, P < 0.003); fewer leaves were produced by seedlings, saplings and adults at the annually harvested site (ANOVA, P < 0.027). Survival was high at all sites across all size classes; in the annually harvested site, A4 plants showed a decrease in survival (one dead out of four plants). Sex ratio of adults that produced cones during the four years of study was 61% males to 39% females. At the non-defoliated site, adult classes A2 and A4 produced >80% of the cones; no cones were produced by the A3 and A4 adult size classes at the annually harvested site."

"Asymptotic estimates of population growth indicated growing populations (λ≥1): the highest mean values of finite population growth rate were obtained in the non-harvested site (λ = 1.0202). Elasticity analysis with population projection matrices indicated that stasis (L, 9-38%) was the component that most contributed to λ, followed by growth (G, 1.2-2.9%), and fecundity (F, 0.2-1.1 %). We observed detrimental effects on several vital rates due to continued long-term defoliation, although population growth parameters do not currently suggest a decreased trend as a result of the annual harvest of leaves. The duration of this study of a very long-lived plant species suggests caution when setting levels and frequency of leaf harvest. The results help pinpoint practical recommendations that could be implemented in a sustainable management plan for this species, particularly to increase seed production in the annually harvested site, and recruitment of new germinants and seedlings at all sites. However, sound practices will need to consider the interests of involved stakeholders (landowners, pilgrims, conservation organizations and authorities) to effectively reduce anthropogenic pressure on this endangered species."