Ecological research in Nicaragua

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contribution to the overall quantitative genetics of physiological traits known or strongly suspected to be correlated with total fitness variation. Nevertheless, direct measurement of fitness differences will continue to be an unrealistic and illusory goal. Acknowledgement I would like to thank reading an earlier version

David Houle of this article

fol

References

I Lewontin, R.C. II9741 The Cenetitaf Basksof Evolutionary Change, Columbia University Press 2 Dykhuizen. D. and Hartl. D.L II9801 Genetics 96,801-817 3 Hart1 D.L. and Dykhuizen, D. II981 1 Proc. Nat1 Atad. Sri USA 78,6344-6348 4 Dykhuizen D. and Hartl, D.L. 119831 Ccnelits 105, I - I8

5 Dykhuizen, D., de Framond. I and Hartl, D.L. I I984 I Mol. Biof. Erol I, 162-l 70 6 Eanes W.F. II9841 Cenrtits IOh. 95-107 7 Eanes, W.F and Hey, I 119861 Gc~nct~ts11’3, 679-693 8 Eanes, W F, Bingham. B.. Hey, I and Houle. D I I9851 Gcnctits 109, 379-39 I 9 Bijlsma, R and van Delden I lY7il Gcncl Res. 30,221-236 IO Bijlsma. R. II9781 GPM~I Rrs. 31, 227-217 I I Voelker. R.A Langley, C.H.. Leigh Brown, E. A 1 Ohnishi, S Dickson, B Montgomery, and Smith S.C. II9801 Proc. Naff Acad Sti. USA 1091-1095 I2 Langley, C.H.. Voelker, R A., Leigh Brown, Al Ohnishi, S Dickson, B. and Montgomery, E ll98llGr~etits99, 151-156 13 Allendorf, F W., Knudsen, K L and Blake, G M. II9821 Gcnefits 100. 497-504 I4 Voelker. R.A Schaeffer, H.E. and Mukai, T I I9801 Genetics 94,96 l-968 I5 Crow, J.F and Kimura, M I IYiOl An lrrtrodlrttlon lo PopltlalioM Cenrtlts Theory, Burgess Publishing Company I6 Kacser. H and Burns, I A I I9731 Symp. Sot. Exp. Biol 27, 65-104 I7 Kacser, H. and Burns. I A / 1979 I Biorhcnl

Ecological Research inNicaragua Alison G, Power Shortages of funds and personnel have restricted the development of ecological research in Nicaragua. These problems are exacerbated by the current war between the forces of the government and the Contras. In spite of these difficulties, there has been considerable recent progress in research that focuses on urgent environmental problems - especially agricultural ecology and conservation biology. The Western hemisphere’s largest tropical rain forest north of the Amazon basin receives relatively little attention from environmentalists or researchers. Although 11 000 km’ of this forest is officially protected in the Bosawas Natural Resources Reserve, most of the reserve remains unmapped and the flora and fauna remain uninventoried’. While the Amazonian rain forest and its spewidely known to be cies are threatened by large-scale development projects and the more gradual erosion from subsistence agriculture, the Bosawas is threatened by a somewhat more complex set of factors. For the Bosawas lies in the northeastern corner of Nicaragua, an area where the war between the Nicaraguan government and the ‘Contras’ (US-supported rebels operAlison Power is at the Section of Ecology and Systematics, Division of Biological Sciences, Cornell University, Ithaca, NY 14853,USA.

ating out of Honduras) is most intense. Like many developing countries, Nicaragua has few resources to devote to ecological research and few trained scientists to carry it out. This condition is exacerbated by the current war. Nicaragua spends much of its income on defense, leaving relatively little for essential social services such as health and education. At the same time, there is a scarcity of experienced researchers since many of the scientists with advanced degrees left the country after Somoza was overthrown in 1979. While many young scientists are now being trained, they must generally study outside Nicaragua to receive graduate degrees. The lack of scientists and funds means that only the most urgent research can be carried out. Current ecological research is thus concentrated in two areas of applied ecology: agricultural ecology and conservation ecology. Despite the war, the Nicaraguan government is concerned with preserving the rain forest and the diverse fauna, which includes 750 species of birds, 600 species of amphibians and reptiles, 200 species of mammals and 100 species of freshwater fish2. Much of the Pacific side of Nicaragua consists of agricultural lands, and here too, an understanding of the basic biology of the system is necessary for effective management. Ecological re-

1987

Sot TrapIs. 7. I I49- I I60 I8 Kacser, H and Burns, I A II981 I Gcnehts 97.639-666 I9 Fisher, R.A. I 19581 The Crnelltaf Throry of Nallrral Srlrtliotl l2nd ednl, Dover Books 20 Wright, S. II9291 Am Nat 63,556-561 21 Wright, S. II9341 Am Nal. 68, 25-53 22 Watt.W.ll985lAm Nat. 125, 118-143 23 Burton, R.S. and Place, A R. II9861 Cenetits 114. 1033-1036 I H I I9761 Atn. Nal I IO, 24 Gillespie. X09-82 I 25 Cavener. D R and Clegg, M.T I 19X I I Pro<. Natf Atad. S(i. USA 78. 4444-4447 26 DiMichele, L and Powers, DA II9821 Natfrrr 296, 563-564 27 DiMichele. L. and Powers, D A I I9821 Sticnce216. 1014-1016 28 Burton, R S and Feldman. M W II9831 2 I, 239-25 I B~othetn Gmel 29 Hilbish. T I and Koehn, R K. II9851 Smvtr 229,52-54 30 Middleton, R.1 and Kacser. H I I9831 Crnrfits 105, 633-650 31 Connors. E M. and Curtsinger, I W II9861 BiochrIn Crnrt. 24, 245-257 32 Wright, S I I93 I I Cenrt~s16. 97-l 59

search in agricultural systems is directed towards the adoption of environmentally sound technologies and development strategies3. Agricultural ecology Agricultural ecology is expanding rapidly in Nicaragua, because it is considered a priority by the government and because study areas are relatively accessible despite the war. Excessive pesticide use in cotton cultivation during the past 30 years has led to an explosion of insecticideresistant pests, a loss of the natural enemies of these pests, extensive pesticide contamination of the environment, and thousands of insectifarm cide poisonings among workers4. As the effectiveness of pesticides has dropped due to the evolution of resistance, the cost of these petroleum-based products has risen along with the cost of fertilizers. Thus there are sound economic reasons, as well as environmental and health-related reasons, for the government’s interest in promoting low-input, sustainable agricultural systems. The most successful application of ecological research in agricultural systems has been the implementation of an integrated pest management (IPM) program in cotton. An IPM program was initiated in 1970 with the help of the Food and Agriculture Organization of the United Nations (FAO) and the US Department of Agriculture’, but it only lasted until the mid-1970s, for a variety of economic and political reasons4. The program, revised and reinitiated in 1982, emphasizes an understanding of the life history of

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1987

the major insect pests, particularly the boll weevil Anthonomus grandis. One of the more innovative aspects of the program is the disruption of the normal breeding and overwintering cycle of the boll weevil by planting post-harvest and pre-planting ‘trap crops’6. These small strips of cotton, planted when cotton is not normally available to the weevil, attract weevils which would otherwise be estivating. Insecticides are then used to eliminate the weevils in these strips before the commercial cotton crop is planted, allowing a tremendous reduction in insecticide application during the normal cropping season. The program also utilizes biological control methods against lepidopterous pests, including: mass release of the parasitoid Trichogramma, application of the bacterium Bacillus thuringiensis, and application of nuclear polyhedrosis virus4. The integration of these various methods is implemented by over 180 scouts who monitor pest abundance and distribution in the cotton-growing area of northwestern Nicaragua. The cotton IPM program is thus at and the implementation stage, although further ecological knowledge about interactions between pests and natural enemies will aid in refining the control techniques, the most basic information is already at hand. This is not the case for most of the other important crops in Nicaragua, particularly the food crops. A new emphasis on food selfsufficiency has led to increased interest in improving production of maize, beans and rice without dramatically increasing purchased inputs. The ministry of agriculture recognizes that this depends on an adequate understanding of the relationship between crops and pests, and encourages ecological studies in these agricutural systems. Research topics range from the most basic studies of pest population dynamics and the identification of their natural enemies7 to more complex investigations of plant competition and the effects of intercropping on generalist herbivorous insect?,‘. The extensive work on the ecology of insects and pathogens which attack maize is a good example of the innovative approach to agricultural research being fostered in Nicaragua. Researchers are examining the population dynamics of the two key insect pests of maize, the fall armyworm Spodoptera frugiperda and the corn leafhopper Dalbulus maidis, during the three potential growing seasons (May-August and September-December under natural

m Cloud forrst m Fig. 1. Map of Nicaragua.

Ek-iduour forest showing

m

ocucpine6

E3

Swnmp

Ccustal pines

I::=21

Ibbgrwcforest

the major forest communities

rainfall, January-April under irriinvestgation) lo . As a preliminary igation of the potential of biological control, the natural incidence of various fungal pathogens of pest insects (including Nomuraea rileyi which attacks the fall armyworm and which Metarrhizium anisopliae attacks the leafhopper) is being monitored throughout the maizegrowing areas. At the same time, laboratory workers are searching for locally available substrates that could be used to produce the pathogens on a commercial scale without importing expensive synthetic diets. A series of experiments has been undertaken to investigate the ecology and epidemiology of the corn stunt spiroplasma, a pathogen transmitted to maize by the corn leafhopper. Based on theories about leafhopper foraging and behavioral responses to vegetation characteristics, these experiments examined the effects of plant diversity, plant density, host plant quality and genetic diversity on leafhopper abundance and the transmission of corn stunt (A.G. Power, PhD, University of Washington, The results 1985).

(from

Ref

161.

emphasize the importance of understanding vector movement behavior when studying the spread of insecttransmitted pathogens, since movement patterns may influence disease incidence independently of vector abundance. The data indicate that manipulating plant diversity through intercropping or adjusting weed cover could be a useful technique for reducing disease spread. Intercropping with beans is a traditional method of peasant maize production: on the basis of this work on corn stunt and previous research on the fall armyworm”, peasants can be encouraged to continue utilizing these systems. Furthermore, in the large mechanized monocultures of maize that are becoming increasingly common in Nicaragua, manipulations of planting density, fertilizer level and varietal diversity may effectively reduce yield losses to both corn stunt and the fall armyworm (Ref. 11; A. G. Power, lot. cit.). This type of applied ecological research can thus provide insights into basic ecological processes like insect foraging and disease spread, yet also lead to practical recommendations to farmers. 49

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Conservation biology

In comparison with other Central American countries, Nicaragua has a relatively low population density: three million people in 130 000 km*. However, the majority of the population lives on the Pacific coastal plain, where most of the agricultural development has occurred. While the semiwas original vegetation evergreen rain forest and deciduous forest, by 1960 no primary stands remained and few mature secondary stands could be found”. This area is now primarily pasture and crop land (Fig. 1). In the Atlantic region of the country, large areas of primary rain forest have survived despite the activities of North American timber companies from the turn of the century until 1960, and massive clearing by cattle ranchers during the 1970s. Unfortunately, the same cannot be said for the two pine communities which represent the southern limit of the genus Pinus. The pine savanna (P. caribaea), which covered an extensive area on the North Atlantic coast, was largely clear-cut by US timber companies in the 1940s and 1950s. Reforestation projects have been a major component of the sustainedyield forestry development project since 1980, but efforts to regenerate the pine savanna have been thwarted by the war. The Contras have targeted reforestation projects and, during a single attack in 1983, 400 km* of coastal pine were destroyed13. The ocote pine (P. oocarpa) of the central highlands has fared slightly better: while it was decimated by transnational companies in the 197Os, over 3000 acres have been replanted in the past few years. There have also been attempts to protect rare and endangered animal species. A number of species are the subject of seasonal hunting bans, and the green turtle (Chelonia mydas) is now totally protected except for subsistence hunting by the coastal Miskito indians*. Some nesting areas for the Pacific olive ridley turtle (Lepidochelys olivacea) are also protected from harvesting, although these areas involve less than 15% of the total breeding population13. Such conservation measures depend largely on information gathered in other countries, however. Population studies of endangered species are carried out by Nicaraguan scientists, but the scope of these projects is usually small. The research often focuses on species which are commonly harvested for food, such as the reptile iguana iguana, in order to improve 50

management. Much of this work is not published in the open literature and therefore is not available except to the government agencies responsible. A further problem is simply the uncertainty involved in carrying out research in wartime. For example, a recent study of the social behavior of the oropendula Gymnostinops montezuma was abruptly terminated when the study area in the central highlands had to be evacuated because of increasing contra activity14. This type of problem makes it difficult to begin long-term ecological studies, despite their usefulness for informing conservation policy. This is particularly true in the least modified, least populated natural areas, such as the rain forest, because these areas are the most susceptible to use by contra groups. Despite these severe limitations, the future of conservation biology in Nicaragua appears bright, largely because of the enthusiasm and dedication of the scientists and teachers who make up the Association of Biologists and Ecologists of Nicaragua. This organization was formed in the early 1980s to promote an ecological approach to resource management and provide a forum for scientific exchange within the country. At the annual meetings, researchers present papers on a wide range of topics, from basic investigations in population biology to management methodologies. A second center of ecological research is the School of Ecology and Natural Resources of the University of Central America in Managua. Some 1500 students are enrolled in the three divisions of the school: flora and wildlife, forestry, and agriculture l3 . About 500 of these students are members of an environmental organization called ‘Habitat’ which publishes a journal of the same name. A recent representative issue of Habitat included an article on birds of prey in Nicaragua, instructions for the design and use of fish-egg incubators in aquaculture, a study of bird social behavior, and a dichotomous key to Nicaraguan reptile families15. While this journal is published at irregular intervals and is not widely distributed outside Nicaragua, it serves the important function of disseminating within the country information about local ecological research and interests. The future of ecological research It is likely that ecological research in Nicaragua will continue to focus on the urgent environmental problems related to development, with

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wildlife and pest management as priorities. This is a necessary and appropriate response to scarce resources, both monetary and human. In order to continue to utilize this type of research in an organized program of sustainable development, and to develop the capacity for fundamental ecological studies, Nicaragua will need both technical and financial aid. Perhaps more importantly, it is essential that the war with the Contras come to an end, so that studies can be carried out in remote but endangered areas like the tropical rain forests of the Bosawas Reserve. Given the opportunity, Nicaragua could be an ideal site for research in tropical ecology, both pure and applied.

References 1 Boucher, D. (1984) Contre-temes 1, 15-17 2 Karliner, J. N., Faber, D. and Rice, R.A. (1986) Nicaragua: an Environmental Perspective, EPOCA 3 Feeney, A. (1984) Environ. Action April 1984,16-20 4 Swezey, S.L., Murray, D.L. and Daxl, R.G. (1986) Environment28,6-9 and 29-36 5 Sequeira, A. (1975) Enagronomia 1, 8-16 6 Daxl, R. and Bodan. R. (1977) IV Seminario Tknico Algodonero, Banco National de Nicaragua 7 Lacayo, L.I. (1984) Programa Cooperativo Centroamericano para el Mejoramiento de Cultivos Alimenticios 30,23 8 Rosset, P.M., Vandermeer, J., Cano, M., Varrela, G., Snook, A. and Hellpap, C. Agronomia Costarricense (in press) 9 Rosset, P.M., Diaz, I., Ambrose, R., Varrela, G. and Snook, A. Turrialba (in press) 10 Gadea, A. and Power, A. (1984) Programa Cooperativo Centroamericano para el Mejoramiento de Cultivos Alimenticios 30, 21 11 van Huis,A. (1981) Meded. Landbouwhogesch. 81 (6) 12 Taylor, B.W. (1963) J. Ecol. 51,27-54 13 Pfeiffer, E.W. (1986) Environ. Conserv. 13,137-l 42 14 Carrasco, G. (1986) Habitat2 (9). 14-16 15 Habifat 2 (9) (1986) 16 Corrales, D. (1983) lmpacro Ecoldgico Sobre /OS Recursos Naturales Renovables de Centroamerica (case particular de Nicaragua), IRENA