D.L. Rogers18, J.J. Vargas Hernández19, A.C. Matheson20, and J.J. Guerra Santos21
On May 14, 2001, 14 people from five countries struggled along a precarious ridge within the inhospitable landscape of Guadalupe Island, Mexico. Their mission was to collect seeds from the few remaining trees of Monterey pine (Pinus radiata D. Don) on this island for genetic conservation, restoration, and research purposes; to describe the status of the trees and their ecosystem context; and to illuminate the urgent situation and conservation needs for this native gene pool of an internationally significant commercial plantation species. The pine population on Guadalupe Island, Mexico's westernmost land, is one of only five native populations of Monterey pine (Figure 1).
Figure 1: Map of the area of natural distribution of Pinus radiata
Organized by the authors of this paper, this trip was inspired by the dire situation of the pines on Guadalupe Island, having had no successful regeneration for decades (Ledig et al. 1998). Goats introduced to the island in the 1800s have multiplied far beyond the habitat carrying capacity, and any pine seedlings are eaten shortly after germination. The remaining pines, approximately 200 in number, are all very old. The pines here are very different from their mainland California relatives. The trees are very large in diameter, with widespread branches and wind-broken tops. Various genetic studies over the last 15 years have confirmed a high level of genetic differentiation among the five native populations of this species. Indeed, varietal names have been given to the mainland (var. radiata) and island (var. binata) populations, and some taxonomists even give separate varietal names to the island populations (Guadalupe = var. binata, Cedros = var. cedrosensis).
Although there are some seeds remaining in seedbanks in California and Australia from a previous seed collection trip in 1978 (Eldridge 1978), those seed supplies have diminished in number by use and in viability over time. Further, there was a need to increase the diversity of the ex situ genetic collections by sampling from as many of the remaining trees as possible before they died, allowing opportunities to restore the natural populations if and when the goats were controlled or removed. Genetic research on these seeds can provide insight into the genetic relationships among the trees, determine the level of inbreeding, and provide direction for restoration efforts.
Expedition members mapped and described individual trees, checked for insect and disease damage, and collected cones from almost half of the remaining trees. The main reason for not collecting seeds from all of the trees was their location along steep slopes, making the effort too risky. After five days on Guadalupe Island, expedition members reboarded their charter boat `Searcher' and continued south to Cedros Island, just off Baja California. The pines on this Mexican island are not in any apparent danger of extinction. The pines here are far more numerous than those on Guadalupe Island and grow in stands of various sizes from the middle to the northern end of the island. As on Guadalupe, they grow only in the upper elevations, along mountain ridges and, in a few cases, in (intermittent) stream gorges. But unlike their Guadalupe Island relatives, many of the pines are young and of the same age: indications that they have grown up quickly and uniformly after a major disturbance (fire). And although goats have also been introduced to this island, they have not multiplied significantly and there does not appear to be any direct threat to the pines from grazing. If there is a threat to the pines here, it might be from future changes in the fire cycle. Not only are the pines in general quite young (apparently), but in some stands it was difficult to find any that had reached reproductive maturity. If the average period between fires on this arid island shortens, because of climate change, for example, or increased human impact, reproduction might be negatively affected. Seeds were collected from trees on this island in a design suitable for studying fine-scale genetic structure and investigating the level of inbreeding.
Guadalupe Island is remote, lying some 280 km off the coast of Baja California. The pines there are a challenge to access, being located only at the north end of this volcanic-origin island and spread out sparsely along the uppermost elevations and down steep slopes (see photo below22). As such, this expedition was a logistical, financial, and physical challenge for the organizers and other participants. Funding for the trip came from a variety of sources (see acknowledgements).
Monterey (or radiata) pine is currently grown in plantation culture on over 4.1 million hectares worldwide, primarily in the southern hemisphere countries of New Zealand, Chile, Australia, Argentina, and South Africa. Some significant plantations of this species are also grown in the northern hemisphere, most notably Spain. Total plantation area dwarfs the amount of native habitat remaining for the species: the current natural range of Monterey pine covers less than two-tenths of one percent of the plantation area. In Chile, Australia, and New Zealand, these plantations represent a major commercial activity. In Australia, for example, Monterey pine plantations account for 75 percent of the total pine plantations currently established. Current value of the sawn timber produced from the total pine plantations is over US$550 million. Although these and other countries where Monterey pine is grown commercially have their own advanced-generation stock and seed banks, the native gene pools in California and Mexico remain of interest. Genes and gene combinations from the native populations could be useful in enhancing traits that are currently valued or determining traits of future interest. Genetic diversity within the Guadalupe Island population, for example, may be useful in improving drought hardiness or resistance to red band needle blight (caused by Scirrhia pini [Mycoshaerella pini]). Both island populations have been shown in field studies to have somewhat thinner bark, higher wood density, and greater frost resistance than the mainland populations-all traits of interest in some plantation contexts. Most importantly, there is interest and concern that the native gene pools regain or maintain their ability to naturally regenerate and respond to natural processes. This dynamic state and purity of stock are near impossible to recreate in ex situ genetic reserves.
Conserving the natural resources on Guadalupe and Cedros Islands is a matter of national and international interest and pride for Mexico and, in the case of Guadalupe Island, a matter of policy. That island is under the protection of the Ministry of the Environment and Natural Resources through the National Commission for Natural Protected Areas (CONANP) and the National Institute of Ecology (INE). The two island pine populations are also classified as `endangered' in the Red List of the International Union of Nature and Natural Resources (Hilton-Taylor 2000). However, it is difficult to translate this interest into the direct activities needed for protection and restoration, mainly because of insufficient funding. The major immediate needs for the islands are goat removal (from Guadalupe Island) and funding for conservation and research. Goat removal should be immediate to build on the recent efforts by some Mexican ranchers who removed several thousand goats and to prevent further erosion of Monterey pine and other native species. However, it should be done within the context of a broader plan that considers and mitigates the possible explosion of exotic invasive plant species following release from grazing pressure. In addition to financing the goat removal effort, funds are also needed for island visits, monitoring efforts, restoration (if required), research, longterm ex situ conservation, and production of public education documents (regarding the value and significance of the pines and precautions against introduction of diseases such as pitch canker that could be fatal to the pines). Recently, the FAO and the University of California (including the UC MEXUS program and the Pacific Rim Program) provided some funding towards research and conservation efforts for these pine populations.
The conservation and technical outcomes from the 2001 expedition continue to accumulate. The seeds have been extracted from the cones and currently reside at the new forestry germplasm bank of CONAFOR23 in Mexicali, Mexico. Risks to the ex situ collections will be minimized by maintaining a portion of the seeds at several facilities. Genetic research on some of the seeds is being planned that would inform conservation and restoration activities by indicating levels and patterns of genetic diversity and inbreeding. The modest proportion of filled seed for some individual trees has already signaled some evidence of inbreeding depression.
The profile of the pines - which will hopefully contribute to the political will and the public constituency for conservation - continues to rise as presentations are given by the participating scientists in the USA, Mexico, and Australia. They continue to work on behalf of genetic and overall conservation of the island pine populations by explaining to government officials the significance of these island populations, by writing funding proposals, and by providing information and recommendations about the pines to related plans and conservation activities. The interest of scientists from the Southern hemisphere in Pinus radiata conservation was highlighted in an earlier issue of this bulletin (Matheson et al. 1999). Several publications are in preparation, including a journal article on genetic conservation of the island populations and a report on in situ genetic conservation of Monterey pine, containing information on the status and conservation needs of the five native populations (Rogers 2002). Although the latter report puts more emphasis on the mainland California populations, there is some information and recommendations for the island populations. Finally, complementary activities for in situ and ex situ conservation of Monterey pine are under development in various countries. For example, a recently released report from CSIRO (Eldridge 2002) calls for a leading role by CSIRO and the Southern Tree Breeding Association in maintaining the integrity and longevity of genetic resources of Monterey pine in Australia, and gives specific recommendations towards achieving that objective. And a binational nonprofit organization (Island Conservation) is developing a plan and fundraising for a comprehensive goat removal effort. If the momentum from this international collaboration continues and effectively translates into funding and conservation action, the Monterey pines on Guadalupe and Cedros Islands, and the genetic heritage they contain, may be able to move from `endangered' status to a more optimistic category.
More of the story at http://www.grcp.ucdavis.edu/projects/MPGCdex.htm
Eldridge, K.G. 1978. Seed collections in California in 1978. p. 9-17 In: CSIRO Division of Forest Research Annual Report 1977-78. CSIRO. Canberra, Australia.
Eldridge, K.G. 2002. Conservation of Genetic Resources of Radiata Pine: CSIRO Role. CSIRO Forestry and Forest Products Divisional Report No. 180.
Hilton-Taylor, C. (compiler) 2000. 2000 IUCN Red List of Threatened Species. IUCN, Gland, Switzerland and Cambridge, UK. xviii + 61pp. (www.redlist.org ).
Ledig, F.T., J.J. Vargas Hernández, & K.H. Johnsen. 1998. The Conservation of Forest Genetic Resources - Case Histories from Canada, Mexico, and the United States. Journal of Forestry, 96(1): 32-41.
Matheson C., Spencer D. and Eldridge K., 1999. A Workshop on Issues and Strategies to Conserve the Genetic Resources of Pinus radiata Ex situ. Forest Genetic Resources No 27. FAO, Rome. 75-78.
Rogers, D.L. 2002. In situ Genetic Conservation of Monterey Pine (Pinus radiata D. Don):
Information and Recommendations. Genetic Resources Conservation Program, Report No. 26. University of California, Davis, California, USA. Also available at: http://www.grcp.ucdavis.edu/publications/MPinedex.htm
We thank the following organizations for sponsoring the expedition: the Food and Agriculture Organization of the United Nations; UC MEXUS (a University of California program aimed at increasing collaboration between UC and Mexican scientists); the Australian (federal) Department of Industry, Science, and Resources; the University of California's Genetic Resources Conservation Program; the Commonwealth Scientific and Industrial Research Organization (Australia); and personal contributions from several of the participants. In addition to the four principle investigators, the participants included five conservation-spirited Americans who provided various resources for the expedition (David Bates, Richard Hawley, Carl Jackovich, Laurie Lippitt, and Nicole Nedeff), two Mexican scientists (Javier López Upton, also from the Colegio de Postgraduados, and Ernesto Franco, California State University Monterey Bay and CICESE, Mexico), a graduate student from UC Berkeley (Tadashi Moody), and two Mexican conservation authorities from the Área de Protección de Flora y Fauna (Ana Ma. Padilla Villavicencio and Celerino Montes). We thank the Mexican Ministry of the Environment and Natural Resources and their offices in the National Commission for Natural Protected Areas (CONANP) and the National Institute of Ecology (INE) as well as the Ministry of Interior (Secretaria de Gobernación) and Secretaria de Marina who provided permission and support for the seed collections.
17 Received June 2002. Original language:
18 Genetic Resources Conservation Program, University of California (UC), Davis, California, United States
19 Colegio de Postgraduados, Montecillo, Estado de México, Mexico
20 Commonwealth Scientific and Industrial Research Organization (CSIRO), Canberra, Australia
21 Universidad Nacional Autónoma de México, Cuautitlán Izcalli, Estado de México, Mexico
22 Photo: Jesús Vargas Hernandez
23Comisión Nacional Forestal, Programa Nacional de Reforestacion