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Oviposicin de las preferencias y las tasas de crecimiento de las larvas de Caligo memnon (Nymphalidae: Brassolinae)
Oviposition preference and larval growth rates of Caligo memnon (Nymphalidae: Brassolinae)
Caligo memnon caterpillars specialize on plants in three families, Heliconiaceae, Marantaceae, and Musaceea. These families are in the Order Zingiberales. Heliconiaceae and Marantaceae are native to the Neotropics, but Musaceae is an introduced family. I studied oviposition preference and larval performance of C. memnon on four host plants: Heliconia latispatha and Heliconia stricta (Heliconiacea), Calathea insignis (Marantaceae), and Musa acuminata (Musacea). Results showed that preferred host plants for oviposition did not correspond to the host plant that provided the fastest growth rate for caterpillars. Females preferred to oviposit on M. acuminata even though larval growth was lowest on this species, though not significantly. It may be that C. memnon is exhibiting maladaptive oviposition behavior and the introduced M. acuminata may be confusing the coevolved mechanisms for host plant choice.
Estudi la preferencia en el sitio de oviposicin y el desarrollo de la larva de C. memnon en cuatro plantas hospederas: Heliconia latispatha y Heliconia stricta (Heliconiacea), Calathea insignis (Marantaceae) y Musa acuminata (Musaceae).
Text in English.
Tropical Ecology 2006
Ecologa Tropical 2006
t Monteverde Institute : Tropical Ecology
1 Soil Organic Matter SOM in agro ecosystems and intact cloud forest in The Monteverde area, Costa Rica J. T. Metten Department of Natural Resources, Colorado State University ABSTRACT Properly managed agro ecosystems have great potential for sequestering carbon as Soil Organic Matter SOM Brown et al. 2002; Lal 2005. I measured % SOM, Bulk Density, Total SOM, and Root Biomass in two agro ecosystems , forest fragment, and intact cloud forest in CaÃ±itas and Monteverde, Costa Rica. These data were analyze d to see if agro ecosystems and forests differ in carbon sequestering ability . I found significant differences in % SOM and Bulk Densities between agro ecosystems but when Total SOM was calculated, results were not significant. Analysis on Total SOM alone suggests that agro ecosystems and forest in Monteverde have an equal ability to sequester SOM. However, root biomass may have an important role. When significant data from Aver age Root Biomass was added to Total SOM to calculate an estimate of belowground carbon data became significant. Intact forest was significantly higher in combined Root Biomass and Total SOM than the agro ecosystems and forest fragment. Though the data suggests that agro ecosystems in Monteverde are capable of sequestering considerable amounts of Total SOM, including Root Biomass illustrates the importance of conserving intact forest to maximize carbon sequestration. Resumen Los agro ecosistemas apropiadamente manejados tienen gran potencial para el embargar del carbÃ³n como Materia OrgÃ¡ nica de Tierra MOT Brown et al. 2002; Lal 2005. MedÃ % MOT, la d ensidad del b ulto, SOM t otal, y la Biomasa de r aÃces en dos agro ecosistemas : el fragmento del bosque, y el bosque nuboso intacto en CaÃ±itas y Monteverde, Costa Rica. Estos datos fueron ana lizados para averig u ar si el agro ecosistema y bosques difieren en la habilidad de embargar el carbÃ³n. EncontrÃ© las diferencias significativas en Ã©l % MOT y las d ensidades del b ulto entre los agros ecosistemas pero cuando MOT Total fue calculado, los resultados no fueron significativos. El anÃ¡lisis de solamente MOT Total sugiere que estos agro ecosistemas y el bosque en Monteverde tienen habilidades iguales para embargar MOT. Sin embargo, la biomasa de raÃces puede tener un papel importante . CuÃ¡ndo los datos significativ os del Promedio de la Biomasa de r aÃces fueron agregados al MOT Total para calcular una estimaciÃ³n de carbÃ³n bajo la tierra los datos llegaron a ser significativos. El bosque intacto tuvo apreciablemente mÃ¡s Biomasa c ombinada de r aÃces y MOT Total que los agro s ecosistemas y el bosque fragmentado. Aunque los datos sugieren que los agro e cosistem as en Monteve rde son capaces de embargar unas cantidades considerables de
2 SOM T otal, incluyendo la Biomasa de r aÃces ilustra la importancia de conservar el bosque inta cto para llevar al mÃ¡ximo el secuestro del carbÃ³n. INTRODUCTION The impact of human activities on climate change is clear; since CO 2 emissions first spiked at the beginning of the industrial age, atmospheric carbon has increased by 30% Vitousek et al. 1 997. Warming has led to a 10% decrease in snow cover and ice extent since the 1960 s and this trend is likely to continue . The recently released Stern Review on the economics of climate change identified many more negative impacts of global climate chan ge such as increased flood risk from glacial melting, lowered crop yields, and widespread increases in disease outbreaks Stern 2006. From an ecological standpoint climate change has been implicated in global species declines, including the loss of 67% o f Atelopus spp. Pounds et al. 2006. While the largest producer of greenhouse gasses, the United States, still remains unwilling to ratify the Kyoto Protocol, numerous methods have been identified to either reduce emissions or sequester carbon on a glob al scale. By extrapolating the amount of land needed to sequester sufficient atmospheric carbon Wright and colleagues 2001 identified forests as the only realisti c method . However, poverty and high demand for land makes implementation unlikely. A plau sible alternative with great potential is the use of various agro ecosystems including secondary forest agroforestry, plantations, and improved pastures to increase the Soil Organic Matter SOM pool Lal 2005. Under proper management, the top 48 tropical and subtropical developing countries could sequester 2.3 billion tones of carbon in the next 10 years alone, and for a profit of 16.8 billion dollars according to one estimate Niles et al. 2002. Recovering secondary forest on abandoned land has been fou nd to recapture nearly all soil carbon lost from historical forest within 50 years Brown and Lugo 1990. Effective shade coffee plantations can sequester 46.7 236.7 tons C/HA Dejong et al. 1995. Pasture, while lacking in above ground biomass, has the capacity for great SOM sequestration, comparable or even greater than surro unding native forest Lugo 1986. Other studies have further identified the effectiveness of pasture for restoring soil carbon to degraded ecosystems Neill et al. 1997; Rhoades 2000; Trumbore et al. 1995. The significance for SOM in carbon sequestration, productivity, and sustainable use is great, both globally and in the tropics especially. Seventy five percent of terrestrial carbon is found in soils and of that 14% 216 Pg i s found in the tropics Houghtan et al. 1985; Lal 2005. Higher temperatures can increase the rate of carbon decomposition in the tropics to four times that of temperate areas, but greater biomass accumulation in the tropics makes content equal Jenkinson and Ayanaba 1977; Sanchez 1982. This has implications for effective management to maximize carbon sequestration, as biomass accumulation needs to be maximized and decomposition minimized. For instance, Nestel 1995 found that increased sun exposure in sun coffee monocultures leads to increases in soil temperatures, decreased water, which can caus e soil degradation . Root biomass has been shown to directly increase C in pasture through depth and proliferation ChonÃ© et al. 1991. Though this is just a portion of total organic deposition contributing to SOM, root biomass can further influence SOM by stabilizing erosion, soil moisture, and temperature Lal 2005.
3 Under the current Kyoto protocol only one of the three agro ecosystems discussed, agroforestry , is marketable for ecosystem service payments UNFCCC 2002. Brown and colleagues argue that this is a mistake and that there are numerous opportunities through sustainable agriculture to sequester carbon Brown, S. et al. 2002. The objective of this s tudy is to address this issue by identifying if agro ecosystems and forests differ in carbon sequestering ability. Furthermore, this study provides a first look on SOM sequestration in agro ecosystems of Monteverde, Costa Rica , and will thus provide a basis for further study. Based on past research illustrating high SOM sequestration in agro ecosystems , I predict there will be no significant differences between pasture, coffee, forest fragment, and intact forest. Methods Study Site Four sample sites were used in the Monteverde area, one at the Monteverde Biological Station intact f orest and the other three coffee, pasture, and forest f ragment at the farm of Don Victor Torres, in nearby CaÃ±itas. The farm was chosen for access to agroforestry secondary forest fragment, coffee plantation, and pasture. It is assumed that these agro ecosystems are at equilibrium and are effectively sequestering ca rbon due to proper management. Bulk Density BD Bulk density measurement was adapted from Field and Laboratory Investigations in Agroecology Gliessman 2000. Five composite samples to 15 cm were taken at each site using a 2 cm diameter soil core. The five composite samples were taken at 10 m, 30 m, 50 m, 70 m, and 90 m and consisted of three sub samples at each location. A drying oven was not available so samples were dried in the attic of the biological station for three days with an avera ge temperature of 26.87 C Â° . Once dried, samples were weighed and density was calculated. % SOM & Total SOM At each site , ei ght composite SOM samples were taken along a 100 m transect. Each sample was composed of 5 sub samples taken every 2.5 meters, from 0 10 m, 12.5 22.5 m, 25 35 m, 37.5 47.5 m, 50 60 m, 62.5 72.5 m, 75 85 m, and 87.5 97.5 m. At each sub sample, aboveground vegetation was removed and soil was excavated to 15 cm using a hand trowel. Soil was then mixed and put through a 2 mm sieve to remove rocks and roots. Samples were then sent to The Ministry of Agriculture Soil Laboratory in San Jose for analysis. Tota l SOM g/m 3 was the percentage of Bulk density comprised of SOM and was calculated by multiplying % SOM with Bulk Density. Root Biomass RB A total of 40 samples were collected, 10 from each site, at 5 m, 15 m, 25 m, 35 m, 45 m, 55 m, 65 m, 75 m, 85 m, a nd 95 m. At each distance a total of 10 sub samples were collected from 0 10 m perpendicular to the transect using a 2 cm diameter soil core at a depth of 15 cm. Samples were then washed using an adaptation of the Central Plains Experimental Range Root W ashing Protocol, dried in the attic of the biological station for 3 days, and weighed Milchunas . Analysis All data were averaged and standard error calculated. Significant differences between data sets were identified using a Kruskal Wallis test .
4 Resu lts Root biomass was significant, and was high est in intact forest and lowest in coffee Kruskal Wallis: X2 = 29.44 DF = 3.00 p = 0.00 . Coffee was significantly lower than the next lowest sites, pasture and intact forest which were statistically equal Figure 1a. BD was also significant but followed opposite trends, highest in pasture and lowest in intact forest Kruskal Wallis: X2 = 16.62 DF = 3.00 p = 0.00 Figure 1b. Similar to RB, i ntact forest had the highest % SOM , but pasture was lowes t instead of coffee Kruskal Wallis: X2 = 20.68 DF = 3.00 p = 0.00 . Forest fragment % SOM was also significantly less than intact forest Figure 2a. When Total SOM was calculated, results were not significant and averages were statistically equal Krus kal A 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 COFFEE PASTURE FOREST FRAGMENT FOREST INTACT Root Biomass g/m^3 B 0.00 50.00 100.00 150.00 200.00 250.00 300.00 COFFEE PASTURE FOREST FRAGMENT FOREST INTACT B.D. g/m^3 A 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 COFFEE PASTURE FOREST FRAGMENT FOREST INTACT % SOM B 0.00 10.00 20.00 30.00 40.00 50.00 60.00 COFFEE PASTURE FOREST FRAGMENT FOREST INTACT Total SOM g/m^3 Figure 2: Avera ge % SOM A and Average Total SOM g/m 3 with standard error bars at the Torres Farm in Ca Ã±itas and the Biological Station in Monteverde. While Average % SOM was significant, Average Total SOM g/m 3 was not. 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 COFFEE PASTURE FOREST FRAGMENT FOREST INTACT TOTAL SOM g/m^3 + RB g/m^3 Figure 3: Average Combin ed Total SOM g/m 3 and Root Biomass g/m 3 with standard error bars at the Torres Farm in Ca Ã±itas and the Biological Station in Monteverde. Data was significant, suggesting belowground carbon sequestration was greatest in intact forest. Figu re 1: Average Root Biomass g/m 3 A and Average Bulk Density g/m 3 with standard error bars at the Torres Farm in Ca Ã±itas and the Biological Station in Monteverde. Root Biomass and Bulk Density showed an inverse relationship.
5 Wallis: X2 = 4.15 DF = 3.00 p = 0.25 Figure 2b. Adding RB to Total SOM provided significant results with intact forest having the highest value Kruskal Wallis: X2 = 9.32 DF = 3.00 p = 0.03 Figure 3. Forest Fragment was significantly less than Intact Forest Figure 3. Discussion The significant results from BD and RB show an inverse relationship between the two across all sites. Low BD in intact forest is likely due to high litter fall and as a consequence has made root proliferation easier, which explains high RB occurring there Figure 1a,b . BD was high in pasture and coffee which is explained by human and livestock compaction occurring at those sites Figure 1b . Interestingly, RB in pasture was much grea ter than coffee despite its BD. High BD in pasture did restrict roots to being ve ry fibrous which explains why RB is so much less than it is in intact forest. Coffee RB may have been further reduced due to weed trimming and monoculture. While RB for forest fragment was statistically eq ual to pasture, it was significantly lower than intact forest. Much less understory was observed during sampling of forest fragment than intact forest, which may have contributed to this finding. Similar to RB, % SOM also showed an inverse relationship t o BD 2a,b . As soil is compacted, its composition of SOM decreases while inorganic matter increases. These data may also be supported by comparing RB to % SOM. Greater RB in intact forest suggests that there is also a greater amount of decomposing and already decomposed roots which would directly add to % SOM. Furthermore, indirect properties of roots, such as erosion, temperature, and moisture control could be further influencing % SOM. The inverse relationship between BD and % SOM equalized values f or Total SOM, making differences between sites not significant. These data suggest that pasture, coffee, and forest fragment at the study site can sequester equal amounts of Total SOM Figure 2b . Past research in pasture, secondary forest, and coffee al l support these findings Rhoades 2000; Lugo and Brown 1992; Dejong, et al. 1995. However, Total SOM is not a complete picture of belowground carbon. Adding RB to Total SOM made data significant which shows the importance of RB in belowground carbon seq uestration. Intact forest was significantly higher than the other three sites due to the direct and indirect contribution of RB Figure 3 . The r esults of this study have numerous implications and questions for further understanding of belowground carbo n sequestration in the Monteverde area. Though intact fores t is significantly different and greater in sequestration ability, the agro ecosystems studied appear to be sequestering high amounts of SOM. Further research is needed to determine if this is a t rend across Monteverde, if SOM is stable, and what management techniques are most effective at increasing SOM within agro ecosystems . Additionally, unintended consequences of management decisions which lead to the release of other greenhouse gases such as N 2 O or cause other environmental problems must be identified. The most important implication of this study is the importance of intact forest for carbon sequestration. Results suggest that belowground carbon storage is greatest in forest; this study did not even discuss the great amounts of above ground biomass which exists in both understory and canopy of the Monteverde cloud forest. Furthermore, the value of intact forest for its ecosystem services such as watershed
6 protection, biodiversity, air qualit y, and even tourism must be recognized. Diversity of forest vegetation may even be a contributing factor to increased SOM in intact forest. Acknowledgements I would first like to thank mi familia Tica for an incredible experience on their farm in Ca Ã±ita s. Nery, you are an awesome cook, sorry I was late to meals so much! Thanks to Mauricio for taking me out harvesting coffee and all of the kids for giving me a workout from so much playing. And many thanks to Don Victor for the use of his beautiful farm in my study. Thanks to Karen Masters for dealing with all my last minute questions and making this study possible. Cam and Tom are the best TA s ever, props for not freaking out from so many ridiculous questions from me and the other 29 students. T hank s to Aidee, Grant and Katie L. for all the excellent help. Literature Cited Brown, S., and A.E. Lugo. 1990. Effects of forest clearing and succession on the carbon and nitrogen content of soils in Puerto Rico and US Virgin Islands. Plant and Soil 124: 53 64 Brown, S., I.R. Swingland, R. Hanbury Tenison, G.T. Prance, N. Myers. 2002. Changes in the use and management of forests for abating carbon emissions: issues and c hallenges under the Kyoto Protocol. In: Philosophical Transactions: Mathematical, Physica l and Engineering Sciences, 360 : 1797 1953 1605 ChonÃ©, T., F. Andreux, J. C. Correa, B. Volkoff, and C. C. Cerri. 1991. Changes in organic matter in an oxisol from the central Amazonian forest during eight years as pasture, determined by 13 C composition. P ages 307 405 in J. Berthelin, editor. Diversity of environmental biogeochemistry . Elsevier, New York, New York, USA. Dejong, B., G. Monoyagomez, K. Nelson, and L. Soto Pinto. 1995. Community forest management and carbon sequestration a feasibility study f rom Chiapas, Mexico. Interciencia 20:6. Gliessman, S.R. 2000. Field and Laboratory Investigations in Agroecology , E. W. Engles, ed. Lewis Publishers, London. pp. 57 59 Griffith, K., D.C. Peck, J. Stuckey. 2000. Agriculture in Monteverde. In: Monteverde: Ecology and Conservation of a Tropical Cloud Forest , Nadkarni, N.M. and N.T. Wheelwright, eds. Oxford University Press, Oxford. pp. 389 417 Houghton, R.A., R.D. Boone, J.M. Melillo, C.A. Palm, G.M. Woodwell, N. Myers, B. Moore, and D.L. Skole 1985. Net fl ux of carbon dioxide from terrestrial tropical forests in 1980. Nature 316:17 620 Jenkinson, D.S. and A. Ayanaba. 1977. D e composition of carbon 14 labeled plant material under tropical conditions. Soil Science Society of America Journal . 41: 912 915 Jenkin son, D.S. and A. Ayanaba. 1977. D e composition of carbon 14 labeled plant material under tropical conditions. Soil Science Society of America Journal . 41: 912 915 Lal, R. 2005. Soil Carbon Sequestration in Natural and Managed Tropical Forest Ecosystems. Jou rnal of Sustainable Forestry . 21: 1 30. Lugo, A.E., M.J. Sanchez. 1986. Land use and organic carbon content of some subtropical soils. Plant and Soil. 96: 185 196
7 Milchunas, D. Monthly Root Harvest Washing Protocol. Accessed from: M. D. Lindquist. email@example.com Accessed: 11/20/06 Neill, C., J.M. Melillo, P.A. Steudler, C.C. Cerri, J.F.L. de Morales, M.C. Piccolo, M. Brito. 1997. Soil carbon and nitrogen stocks following forest clearin g for pasture in the southwestern Brazilian Amazon. Ecological Applications . 7: 1216 1225. Nestel, D. 1995. Coffee in Mexico: International market, agricultural landscape and ecology. Ecological Economics . 15: 165 178 Niles, J.O., S. Brown, J. Pretty, A. S. Ball, J. Fay. 2002 Potential Carbon Mitigation and Income in Developing Countries from Changes in Use and Management of Agricultural and Forest Lands. In: Philosophical Transactions: Mathematical, Physical and Engineering Sciences, 360 : 1797 1621 1639 P ounds, J.A, M.R. Bustamante, L.A. Coloma, J.A. Consuegra, M.P.L. Fogden, P.N. Foster, E. La Marca, K.L. Masters, A. Merino Viteri, R. Puschendorf, S.R. Ron, G.A. SÃ¡nchez Azofeifa, C.J. Still, and B.E. Young. 2006. Widespread amphibian extinctions from epid emic disease driven by global warming. Nature . 439: 161 167. Rhoades, C.C. 2000. Soil Carbon Differences among Forest, Agriculture, and Secondary Vegetation in Lower Montane Ecuador. Ecological Applications. 10:2 497 505 Sanchez, P.A., M.P. Gichuru and L. B. Katz. 1982. Organic matter in major soils of the tropical and temperate regions. Translated 12 th International Congress. Soil Science 1 New Delhi. Sanchez, P.A., M.P. Gichuru and L.B. Katz. 1982. Organic matter in major soils of the tropical and temp erate regions. Translated 12 th International Congress. Soil Science 1 New Delhi. Stern. 2006 . Stern Review on the economics of climate change. http://www.hm treasury.gov.uk/independent_reviews/stern_review_economics_climate_change/stern_review_report.cf m Accessed. 11/20/06 Trumbore, S.E., E.A. Davidson, P.B. de Camargo, D.C. Nepstad and L.A. Martinelli. 1995. Below ground cycl ing of C in forests and pastures of eastern Amazonia. Global Biogeochemical Cycles. 9: 512 528 UNFCCC 2001 United Nations Framework Convention on Climate Change agenda items 4 and 7. In Proc. Conference of the Parties, 6 th Session, Part 2, Bonn, 16 27 July 2001. Available from http://www.climnet.org/cop7/FCCCCP2002L.7.pdf . Vitousek, P.M., H.A. Mooney, J. Lubchenco, J.M. Melillo. 1997. Human Domination of Earth s Ecosystems. Science 277: 494 4 99 Wright, D.G., R.W. Mullen, W.E. Thomason, W. R. Raun. 2001. Estimated land area increase of agricultural ecosystems to sequester excess atmospheric carbon dioxide. Commun. Soil Sci. Plant Anal. 32: 1803 1812.