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Effects of harvesting intensity on population structure of
Lippia graveolens (Verbenaceae, Lamiales) in the
Semidesert of Queretaro, Mexico
Tamara
Osorno-Sánchez1, Alfonso Torres Ruiz2
and Roberto Lindig-Cisneros1*
1Centro
de Investigaciones en Ecosistemas, Universidad Nacional
Autónoma de México. Apartado Postal 27, Admón. 3, Santa
María, C.P.58091, Morelia, Michoacán, México.
2Universidad
Autónoma de Querétaro, Facultad de Ciencias Naturales,
Laboratorio de Ecología y diversidad Faunística; Querétaro,
México.
*Corresponding author: E-mail:
rlindig@oikos.unam.mx.
Accepted 6 December, 2011 |
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Whole Oregano (Lippia graveolens) is a wild shrub
species that is harvested commercially as an important
complement to the income of farmers in the semiarid areas of
Mexico. However, the impact of this activity on populations
of the species is unknown, particularly in the semi-desert
of Queretaro State in Mexico. We quantified the consequences
of different harvest rates on the growth and reproduction of
five wild populations of L. graveolens, with the goal
of improving current practices. We found that, as the
harvesting rates of L. graveolens increase, there are
changes in the density, size structure, proportion of
reproductive individuals and production of inflorescences.
For instance, in sites with the lowest harvesting intensity,
the density was 2980 individuals/ha, the mean plant height
was 100 ± 3.25 cm (mean ± SE) and mean plant cover was 4312
± 247 cm2; whereas in sites with the highest
plant harvesting intensity the density was 1920
individuals/ha, mean plan height was 30 ± 1.93 cm and mean
plant cover was 843 ± 73 cm2. Such changes place
certain managed wild oregano populations in a vulnerable
situation, illustrating the need of close monitoring of
species harvested from the wild as cash crops.
Key words: Extraction, spices, population dynamics, non-wood
forest products. |
