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Population
Demography Subgroup
Background
The cycad conservation action plan of 2003
clearly states the need to develop detailed population studies, not only
to evaluate the current conservation status of populations, but also to
explore population dynamics in an effort to generate relevant information
for conservation and management purposes. Research on cycad demography and
population ecology can be useful to identify major threats to population
decline and to evaluate the impact of alternative management strategies on
population success. In particular, the
action
plan
proposed to encourage research in small and isolated populations
to determine their long-term viability.
Only a few detailed studies on cycad demography or cycad population
ecology have been carried out in the Neotropics (and published in the
literature). These studies include common species like Zamia
integrifolia in the U.S. (Tang, 1990; Negron-Ortiz & Gorchov, 2000)
and Dioon edule in Mexico (Vovides, 1990), as well as less common
species like Zamia pumila in the Dominican Republic (Ornduff, 1987;
Negron-Ortiz et al., 1996) and Ceratozamia matudai and C.
mirandae in Mexico (Perez-Farrera et al., 2000; Perez-Farrera
et al., 2006). Although these studies provide invaluable
information for cycad conservation, it would be desirable to establish
long-term monitoring programs to continue monitoring these studied
populations and to start monitoring other cycad populations in various
locations around the world.
Goals
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Coordinate the establishment of a network of cycad population monitoring
programs to generate relevant and high-quality biological information for
conservation and for evaluating potential management and use strategies.
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Support the establishment, data collection, and data analysis of
population monitoring programs in collaboration with the institutions or
research groups developing the monitoring in each of the sites of the
network.
Implementation
After the CYCAD 2008 meeting, several potential sites in places like
Colombia, Mexico, South Africa, Guam, and India were identified as
potential sites for the establishment of population monitoring programs.
The Population Demography Subgroup will give technical support to
researchers in these sites to establish or continue with a monitoring
program, in such a way that we can standardize data collection
methodologies that will allow us to use the data for particular
conservation and management purposes. At the meeting the possibility of
linking monitoring programs with local community nurseries was also
discussed, as these two initiatives can benefit from each other’s outputs
to widen the potential for conservation and use of cycads around the
world.
Long-term monitoring programs for populations are relatively easy to
implement (as data gathering may be intensive but not overly complicated),
but ensuring a research commitment for several or many years may be
difficult. The population monitoring program will try to promote research
by ‘stable’ organizations like research groups associated with
universities and conservation NGOs, in an effort to increase the
probability of a long-term commitment to cycad population monitoring.
Some general guidelines for establishing a cycad population monitoring
program have been published as an article in the
Cycad Newsletter, and these can be
used as a starting point for all sites where a monitoring program could be
implemented. An electronic version of this article is available below:
Expected Outputs
In the short term, we hope to create a network of monitoring programs by
coordinating the setting up (or continuation) of population studies in the
proposed sites. This will involve the identification of populations for
long-term monitoring, the establishment of plots for monitoring and
tagging of individuals, and the standardization of data collection
methods.
In the long-term, we expect to coordinate the use of biological
information produced by the programs for conservation and management
purposes. In particular, we expect to be able to use the population
information for increasing our understanding of cycad population dynamics
and population viability, the patterns and mechanisms of conservation
threats, and for evaluating potential strategies for population management
and use (for example by local community nurseries).
Literature Cited
Negron-Ortiz, V., and D. L. Gorchov. 2000. Effects of fire season and
postfire herbivory on the cycad Zamia pumila (Zamiaceae) in slash
pine savanna, Everglades National Park, Florida. International Journal
of Plant Sciences 161:659-669.
NegronOrtiz, V., D. L. Gorchov, and G. J. Breckon. 1996. Population
structure in Zamia (Zamiaceae) in northern Puerto Rico. 2. Seed
germination and stage-structured population projection. International
Journal of Plant Sciences 157:605-614.
Ornduff, R. 1987. Sex-ratios and coning frequency of the cycad Zamia
pumila L (Zamiaceae) in the Dominican-Republic. Biotropica
19:361-364.
Perez-Farrera, M. A., P. F. Quintana, B. Salvatierra, and A. P. Vovides.
2000. Population dynamics of Ceratozamia matudai Lundell
(Zamiaceae) in el Triunfo Biosphere Reserve, Chiapas, Mexico. Journal
of the Torrey Botanical Society 127:291-299.
Perez-Farrera, M. A., A. P. Vovides, P. Octavio-Aguilar, J. Gonzalez-Astorga,
J. de la Cruz-Rodriguez, R. Hernandez-Jonapa, and S. M. Villalobos-Mandez.
2006. Demography of the cycad Ceratozamia mirandae (Zamiaceae)
under disturbed and undisturbed conditions in a biosphere reserve of
Mexico. Plant Ecology 187:97-108.
Tang, W. 1990. Reproduction in the cycad Zamia pumila in a
fire-climax habitat: an 8-year study. Bulletin of the Torrey Botanical
Club 117:368-374.
Vovides, A. P. 1990. Spatial distribution, survival, and fecundity of
Dioon edule (Zamiaceae) in a tropical deciduous forest in Veracruz,
Mexico, with notes on its habitat. American Journal of Botany 77:1532-1543.
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