Small mammal diversity and population densities in Monteverde, Costa Rica : A follow- up study of Rothman (1999)


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Small mammal diversity and population densities in Monteverde, Costa Rica :  A follow- up study of Rothman (1999)

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Title:
Small mammal diversity and population densities in Monteverde, Costa Rica : A follow- up study of Rothman (1999)
Translated Title:
Diversidad de mamíferos pequeños y densidades de población en Monteverde, Costa Rica : Un estudio de seguimiento de Rothman (1999)
Creator:
Burdick, Caroline C
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Language:
Text in English

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Subjects / Keywords:
Rodents ( lcsh )
Roedores ( lcsh )
Climatic changes ( lcsh )
Cambios climaticos ( lcsh )
Fragmented landscapes ( lcsh )
Paisajes fragmentados ( lcsh )
Costa Rica--Puntarenas--Monteverde Zone
Costa Rica--Puntarenas--Zona de Monteverde
CIEE Spring 2008
CIEE Primavera 2008
Genre:
Reports

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Abstract:
Widespread deforestation and El Niño events may have an effect on Costa Rican’s climate, and overall, Monteverde’s climate is becoming drier and less predictable due to short-term global warming impacts. Due to widespread habitat fragmentation and hunting, the population of small and medium-sized mammals has decreased dramatically. This study investigates rodent species richness, abundance, and diversity in three life zones in Monteverde, Costa Rica, to determine whether they have changed since a similar study conducted in 1999. Small mammals were sampled in Tropical Lower Montane Wet Forest, Tropical Premontane Moist Forest, and Tropical Lower Montane Rain Forest in the Monteverde region, Costa Rica, during the end of the dry season in mid-April, early-May. Data were collected using thirty 26 x 10 x 12 cm Sherman Live Traps. In 15 nights of trapping (450 total traps), 47 individuals were captured (with a few recaptures). Overall, six species and two orders were represented: Murid and Heteromyid rodents included 33 P. nudipes, six S. teguina, four H. desmarestianas, one O. albigularis, and one R. rattus. Order Insectivora was represented by two soricid shrews, C. gracilis. The mid-elevation site (see comments about “mid-elevation below) had the lowest rodent abundance, and thus differing greatly from the results of Rothman’s study. Furthermore, P. nudipes was absent from this site. Changing climate conditions could be partially responsible for the missing P. nudipes and relatively low abundance in the Tropical Lower Montane Wet Forest life zone, but also chance could play a strong role, as could sampling methods. ( ,,, )
Abstract:
La deforestación y los eventos del Niño pueden haber afectado el clima de Costa Rica, y en general provocando un clima más seco y menos predecible debido a los impactos del calentamiento global a corto plazo. Debido a la fragmentación del hábitat y la cacería, las poblaciones de mamíferos pequeños y medianos han disminuido dramáticamente. Este estudio investigó la diversidad, la riqueza de especies y la abundancia de roedores en tres zonas de vida en Monteverde, Costa Rica para determinar si han cambiado desde que se hizo un estudio similar en 1999.
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Student affiliation : School of Education, University of Wisconsin-Madison
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Born Digital

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Monteverde Institute
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Monteverde Institute
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M39-00434 ( USFLDC DOI )
m39.434 ( USFLDC Handle )

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Widespread deforestation and El Nio events may have an effect on Costa Ricans climate, and overall, Monteverdes climate is becoming drier and less predictable due to short-term global warming impacts. Due to widespread habitat fragmentation and hunting, the population of small and medium-sized mammals has decreased dramatically. This study investigates rodent species richness, abundance, and diversity in three life zones in Monteverde, Costa Rica, to determine whether they have changed since a similar study conducted in 1999. Small mammals were sampled in Tropical Lower Montane Wet Forest, Tropical Premontane Moist Forest, and Tropical Lower Montane Rain Forest in the Monteverde region, Costa Rica, during the end of the dry season in mid-April, early-May. Data were collected using thirty 26 x 10 x 12 cm Sherman Live Traps. In 15 nights of trapping (450 total traps), 47 individuals were captured (with a few recaptures). Overall, six species and two orders were represented: Murid and Heteromyid rodents included 33 P. nudipes, six S. teguina, four H. desmarestianas, one O. albigularis, and one R. rattus. Order Insectivora was represented by two soricid shrews, C. gracilis. The mid-elevation site (see comments about mid-elevation below) had the lowest rodent abundance, and thus differing greatly from the results of Rothmans study. Furthermore, P. nudipes was absent from this site. Changing climate conditions could be partially responsible for the missing P. nudipes and relatively low abundance in the Tropical Lower Montane Wet Forest life zone, but also chance could play a strong role, as could sampling methods.
La deforestacin y los eventos del Nio pueden haber afectado el clima de Costa Rica, y en general provocando un clima ms seco y menos predecible debido a los impactos del calentamiento global a corto plazo. Debido a la fragmentacin del hbitat y la cacera, las poblaciones de mamferos pequeos y medianos han disminuido dramticamente. Este estudio investig la diversidad, la riqueza de especies y la abundancia de roedores en tres zonas de vida en Monteverde, Costa Rica para determinar si han cambiado desde que se hizo un estudio similar en 1999.
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Text in English.
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Rodents--Variation--Costa Rica--Puntarenas--Monteverde Zone
Climate change
Fragmented landscapes--Costa Rica--Monteverde Zone
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1 Small Mammal diversity and Population Densities in Monteverde, Costa Rica: A Follow up Study of Rothman 1999 Caroline C. Burdick Department of Ecology and Evolutionary Biology, University of Colorado Boulder ABSTRACT Widesprea d deforestation and El Ni€o events may have an effect on Costa Ricans climate, and overall, Monteverdes climate is becoming drier and less predictable due to short term global warming impacts. Due to widespread habitat fragmentation and hunting, the pop ulation of small and medium sized mammals has decreased dramatically. This study investigates rodent species richness, abundance, and diversity in three life zones in Monteverde, Costa Rica, to determine whether they have changed since a similar study con ducted in 1999. Small mammals were sampled in Tropical Lower Montane Wet Forest, Tropical Premontane Moist Forest, and Tropical Lower Montane Rain Forest in the Monteverde region, Costa Rica, during the end of the dry season in mid April, early May. Data were collected using thirty 26 x 10 x 12 cm Sherman Live Traps. In 15 nights of trapping 450 total traps, 47 individuals were captured with a few recaptures. Overall, six species and two orders were represented: Murid and Heteromyid rodents include d 33 P. nudipes , six S. teguina, four H. desmarestianas , one O. albigularis , and one R. rattus. Order Insectivora was represented by two soricid shrews, C. gracilis. The mid elevation site see comments about ‚mid elevation below had the lowest rodent abundance, and thus differing greatly from the results of Rothmans study. Furthermore, P. nudipes was absent from this site. Changing climate conditions could be partially responsible for the missing P. nudipes and relatively low abundance in the Tropic al Lower Montane Wet Forest life zone , but also chance could play a strong role, as could sampling methods. RESUMEN La deforestación y los eventos EL Nino pueden haber afectado el clima de Costa Rica, y en Monteverde p r o vocando mayor sequía y un clima e n general menos predecible. Debido a la fragmentación del hábitat y la cacería , las poblaciones de pequeños y medianos mamíferos han decrecido dramáticamente . Este estudio investigo la diversidad, riqueza de especies y abundancia de roedores en tres zonas de vida en Monteverde al final de la época seca. En 15 noches de captura 450 trampas en total se capturaron 47 individuos; seis especies en dos órdenes . El sitio de elevación intermedia presento la menor abundancia de roedores, lo que provoco que este r esultado fuese muy diferente al de Rothman. P nudipes estuvo ausente de este sitio. Las condiciones climáticas cambiantes podrían ser parcialmente responsables por las bajas abundancias de roedores. INTRODUCTION Although Costa Rica boasts an incredible mammal diversity 207 species, few experiments have been conducted on the ecology, distribution, abundance, altitudinal zonation, systematic relationships, biogeography and effect of climatic changes on most mammals. Widespread deforestation and El Niño events may have an effect on Costa Ricans climate. Overall, Monteverdes climate is becoming drier and less predictable due to short term global warming impacts Timm & LaVal 2000. Enquist 2002 suggests that in general, high elevation life zones are particularly sensitive to temperature changes, while lower elevation life zones tend to

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2 be more sensitive to changes in precipitations. With rising global temperatures, geographic ranges increase in elevation, thereby decreasing in size. Due to widespr ead habitat fragmentation and hunting, the population of small and medium sized mammals has decreased dramatically. Many generalist species have adapted to the increase in human disturbance; some have even increased in abundance. However, many specialist s have been unable to adapt to habitat fragmentation and have become extremely rare. This could be because of life zone differences in species abundance and diversity, as they change on an elevational gradient Timm and LaVal 2000. Furthermore, many chan ges in the Monteverde area may have affected, either directly or indirectly, the rodent populations in the past ten years, due to climate change, human disturbance and contamination levels, or the introduction of new predators into the area. Very few stud ies have been done to determine the effect these disturbances have had on the distribution and abundances of small rodents in the tropics. Rothman 1999 completed a study in the Monteverde area to examine effects of climate change and elevation on small rodent populations. He compared his capture rate to a previous study conducted by Stephen Anderson 1982 to determine if the rodent population had changed. No conclusive evidence was found at that time supporting the idea that rodent population varied i n abundance or distribution. A survey conducted by Velez Zuazo et al . 2005 determined that Monteverde has four prominent small rodent species that inhabit the area: Peromyscus nudipes Cloud Forest Deer Mouse, Heteromys desmarestianas Forest Spiny Po cket Mouse, Scotonomys teguina Alstons Singing Mouse, and Oryzomys albigularis Montane Rice Rat. Because of their widespread distribution and opportunistic and omnivorous diet, Peromyscus nudipes Cloud Forest Deer Mouse is known as a generalist sp ecies, thus tolerating both disturbed and forested areas. Therefore it has become the most abundant small mammal in the area Rothman 1999; Nowak and Paradiso 1983. Although the ultimate goal is to understand fluxuations in small mammal populations, and thwart possible losses in abundance, basic census data is needed so that monitoring can begin. This study seeks to determine if there has been a change in abundance of P. nudipes since Rothmans experiment in 1999, and if there is a difference in species richness, abundance, and diversity in small mammals between three life zones in Monteverde, Costa Rica. METHODS AND MATERIALS Study Areas The following three life zones were sampled in this study: Tropical Lower Montane Wet Forest, Tropical Premont ane Moist Forest, and Tropical Lower Montane Rain Forest. Tropical Premontane Wet Forest is a two layered, semi deciduous , seasonal forest of medium elevation between 1300 and 1470 m. Canopy trees are mostly dry season deciduous, understory trees are ever green, the shrub layer is dense, and the ground layer is sparse. Woody vines are abundant, but epiphytes are rare Hartshorn 1983. The second five nights of trapping occurred in this life zone, on land owned by Frank Joyce. Traps were placed along two separate trails; the first trail was narrow and along a ravine, and the other trail was along flat ground with various micro habitats. This area will be referred to as site one from now on. Tropical Lower Montane Wet Forest life zone site two is prim arily restricted to central Costa Rica, is an evergreen forest found at elevations of 1470 to 1600, and has two tree strata. This forest consists of canopy trees, a fairly open understory, and a relatively dense shrub layer.

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3 The ground layer is well cove red with ferns, vines, and moist, rotting leaves. Epiphytes, such as orchids, bromeliads, and meliads, are common Hartshorn 1983. The first five nights of trapping on the property of John and Martha Campbell, in what is commonly called the Bullpen. Th is area was relatively open due to previous deforestation. Traps were placed along the trail in the understory of the forest, along the edge, and out in the open in a tree fall area. Also, traps were set in an open area where remnant, emergent trees rema ined. The final life zone sampled, Tropical Lower Montane Rain Forest, is an evergreen forest above 1600 m. This site will be referred as site three. Ericaceae and Melastomataceae are abundant shrubby epiphytes, and large leaved vines are occasional. Large lianas are uncommon in this area. Canopy trees are mostly 25 30 m tall, and understory stratum is often dense with small trees. The shrub layer is very dense, and the ground layer is well covered with ferns, sedges, and patches of moss Hartshorn 1983. This was the third trapping site for this study, and contains the con tinental divide above La Estaci ó n between 1600 and 1842 m in elevation. Traps were laid along the Sendero Principal trail in various micro habitats, consisting of small trees, un dergrowth, and roots. Sampling Small mammals were sampled during the end of the 2008 dry season from the April 15 th to May 10th. Data were collected using thirty 26 x 10 x 12 cm Sherman Live Traps. Each study site was sampled five times, for a total of 15 nights of trapping. Traps were laid in various micro habitats along trails, most often placed one to five meters apart on alternating sides of the trail. Micro habitats included the underbrush in the forest, edge habitat, the base of trees, among r oots, along logs, and in tree fall areas. Each trap was carefully placed even with the ground so no tipping would occur if a small mammal entered. A mixture of creamy peanut butter and banana slices were used as bait, to be consistent with Rothmans 199 9 study. The thirty Sherman traps were opened each afternoon between 3 and 4, and checked between 7:30 a.m. and 8:30 a.m. the following morning. The trap number, micro habitat, weight, sex, body length, tail length, ear and hind foot length were recorde d when a small mammal was discovered. These measurements were used, with the help of pictures, to identify the species of each captured individual. A hand held Pesola 100g spring scale was used to weigh the individual, and lengths were taken using a dial caliper. Data Analysis The values of H and t were calculated using a Shannon Weiner index of diversity to determine if there was a difference in diversity, evenness and species richness between the three sites sampled. To determine if there was a difference in frequency of species per site, a contingency table analysis was conducted. Finally, a Kruskal Wallis nonparametric test was performed to determine if there was a difference in abundance between sites. Comparisons in capture rates were then made between these data and that of Rothman 1999, who performed a study to determine the abundance of small mammals in Monteverde, Costa Rica.

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4 RESULTS In 15 nights of trapping 450 total traps, 47 individuals were captured with a few re captures. Overall, six species and two orders were represented: Murid and Heteromyid rodents included 33 P. nudipes , six S. teguina, four H. desmarestianas , one O. albigularis , and one R . rattus. Order Insectivora was represented by two soricid shrews, C. gracilis. In the Bullpen Tropical Lower Montane Wet Forest, a total of five individuals were captured including two C. gracilis, two S. teguina, and one H. desmarestianas . This area yielded the least amount of captured individuals than the followin g two sites. The land of Frank Joyce Tropical Premontane Moist Forest produced 23 total captures, 19 of which were P. nudipes ; three were H. desmarestianas , and one that was R. rattus. The final site at the continental divide Tropical Lower Montane Ra in Forest produced a total of 19 captures. Fourteen of the 19 captures were P. nudipes, four were S. teguina, and one was O. albigularis Fig. 1. When comparing P. nudipes to the other species caught, zero P. nudipes and five individuals of other spec ies were captured in site one. Site two produced 19 P. nudipes and four other individuals. The final site generated 14 P. nudipes and five individuals of other species Fig. 2. ƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒ ƒƒƒƒƒƒƒƒƒ Figure 1. Species Richness of Tropical Premontane Wet Forest Site 1, Tropical Lower Montane Wet Forest Site 2, and the Tropical Lower Montane Rain Forest Site 3 Monteverde, Costa Rica ƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒ ƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒ 0 2 4 6 8 10 12 14 16 18 20 Site 1 Site 2 Site 3 Location # of Individuals Caught P. nudipes C. gracilis S. teguina H. desmarestianas O. albigularis R. rattus

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5 ƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒ ƒƒƒƒƒƒƒƒƒ Figure 2. Species Richness in Monteverde, Costa Rica, comparing P. nudipes with other captured species ƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒ ƒƒƒ ƒƒƒƒƒƒƒƒƒƒ There was a difference in diversity between site two n 2 = 5 and site one n 1 = 23, t = 3.18, p < 0.05, with site two having a higher diversity than Frank Joyces land H 2 = 1.05, H 1 = 0.56. Also, site two had a higher species richness than s ite one Smarg 2 = 1.24, Smarg 1 = 0.64 and had a higher evenness E 2 = 0.96, E 1 = 0.51. Furthermore, there was a difference in diversity between site two and site three n 3 = 19, t = 2.33, p < 0.05. Site two had a higher diversity than site one H 2 = 1.05 , H 1 = 0.71, a higher species richness Smarg 2 = 1.24, Smarg 1 = 0.68, and a higher evenness E 2 = 0.96, E 1 = 0.64. Finally, there was no difference between site one and site three, however, site three had a slightly higher diversity than site one H 1 = 0.56, H 3 = 0.71. A contingency table analysis determined that there was a difference between the frequency of species x 2 = 31.4 df = 10, p = 0.0005. In site one; more H. desmarestianas and P. nudipes were caught than anticipated. In site two , there were more C. gracilis and S. teguina captured than expected. Significantly fewer P. nudipes were caught than expected. Finally, in site three, more P. nudipes and S. tequina were captured, while fewer H. desmarestianas were captured than projecte d Table 1. These differences can be seen in Figure 3. 0 2 4 6 8 10 12 14 16 18 20 Site 1 Site 2 Site 3 Location # of Individuals Caught Peromyscus nudipes Other species

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6 Table 1. Chi square test showing the difference in frequency of species per site x 2 = 31.4, p = 0.0005. Site one yielded more H. desmarestianus , P. nudipes, and less S. teguina than pred icted. Capture rates of C. gracilis and S. teguina were higher than expected, while the abundance of P. nudipes was less than predicted in site two. Finally, more P.nudipes and S. teguina were captured than anticipated in site three. According to a Kruskal Wallis nonparametric test, no difference in abundance was found between the three sampled sites H = 0.16, df = 2, n = 18, p = 0.92. When comparing the success rate of Rothmans total captures with this study, defined by Anderson 1982 as the number of rodents captured divided by the total number of traps # captured/ # traps, it was determined that Rothman caught a larger percentage of P. nudipes that the current study. In his study, 70 individuals were caught, 60 of which were P. nudipes, nine were H. desmarestianas , and one of O. albigularis . Refer to Table 2 to compare percentage of captures between Rothman 1999 and this study Burdick 2008. Table 2. Comparison of capture ra tes between Rothman 1999 and that of Burdick 2008 . Study Total Captures P. nudipes C. gracilis S. teguina H. desmarestianas O. albigularis R. rattus Rothman 70 60 0 0 9 1 0 % 86 0 0 13 1 0 Burdick 47 33 2 6 4 1 1 % 70 4 13 9 2 2 x 2 O. albi gularis C. gracilis H. desmarestianus P. nudipes R. rattus S. teguina Site 1 Observed Expected 0 0.489 0 0.978 3 1.956 18 15.644 1 0.489 0 2.444 Site 2 Observed Expected 0 0.111 2 0.222 1 0.444 0 3.556 0 0.111 2 0.556 Site 3 Observed Expected 1 0.4 0 0. 8 0 1.6 14 12.8 0 0.4 3 2

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7 DISCUSSION Due to the absence of P. nudipes, there was a higher species richness, diversity, and evenness between the Tropical Lower Montane Wet Forest life zone and the other two sites. This site was much more even than the other two due to the fact that it was not dominated by P. nudipes . Therefore, because site two and three were both dominated by P. nudipes , their species richness, diversity, and evenness were not different. Rothmans 1999 capture success of P. nudipes in the three lif e zones was much greater 86% vs. 70% than I found. However, more species of rodents and soricids are represented in this survey, therefore giving rise to greater species richness. He found only three species P. nudipes, S. teguina, and O. albigularis , while six species were captured in this study. It appears that the abundance of P. nudipes has decreased since 1999. However, this could also be due to chance or a small sample size, especially since the species was completely missing from one site. Clearly the results for this study are different than those of Rothmans study, where he found a large abundance of P. nudipes in all three of his sampled sites. Here, the highest and lowest elevations Premontane Wet and Lower Montane Rain Forest hel d a disproportionately higher abundance of P. nudipes . However, it was absent from the mid elevation Lower Montane Wet Forest. Also, these data are not consistent with previous work done by McCain 2004 in which the highest capture frequencies was 150 0 1550, the same elevation as the Lower Montane Wet Forest. Therefore, instead of having the lowest success rate, this site should have been the most abundant and diverse. There are numerous possible reasons that may explain why the trapping rates diffe red between this study and Rothmans, spanning simple methodological differences, to chance, and to potential environmental change. Their semi arboreal nature could account for the lack of success in 0 0.5 1 1.5 2 2.5 3 3.5 4 P. nudipes C. gracilis S. teguina H. desmarestianas O. albigularis R. rattus Number of Individuals Caught Site 2 observed Site 2 expected 0 2 4 6 8 10 12 14 16 P. nudipes C. gracilis S. teguina H. desmarestianas O. albigularis R. rattus Number of Individuals Caught Site 3 observed Site 3 expected 0 2 4 6 8 10 12 14 16 18 20 P. nudipes C. gracilis S. teguina H. desmarestianas O. albigularis R. rattus Number of Individuals Caught Site 1 observed Site 1 expected a b c Figure 3. Visual representation of chi square tests x 2 = 31.4, p= 0.0005. a Observed vs. expected values for Site 1 b Observed and expected values for Site 2 c Values for Site 3.

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8 trapping this generalist species, as traps were solely placed on the ground. As for the role of chance, a lot of natural variation in rodent population sizes exists, as they fluctuate from year to year Janzen 1983. Also, this study provided small samples, therefore may not have enough data to prove represe ntative of the population. Lastly, an important consideration for the Monteverde zone is the role that climate change may play in population dynamics. While this study reveals no obvious factor or factors as reasonable for the lack of P. nudipes from th e Tropical Lower Montane Wet Forest life zone, the results here, as well as Rothmans, could provide baseline data for the type of long term monitoring program needed to access population changes. ACKNOWLEDGMENTS I would like to thank the following for the help and support I received during this study: Frank Joyce and Martha Campbell for the use of their land near Bajo del Tigre and the Bullpen, respectively. Thanks are also extended to Marvin Hidalgo , and the employees of the Estaci ó n Biol ó gica for th e use of their forest and resources. A big thank you goes to Federico Chinchilla for his knowledge and identifying skills of small mammals in the Monteverde area. Extra special thanks go to Tania Chavarría and Karen Masters for their help in finding si tes, support, suggestions, and statistical genius. Pablo and Taegan, I owe you my sanity at times. Also, thanks to Laura Grieneisen and Rachel Skalina for their assistance and company in setting up and breaking down my traps you two saved me a lot of ti me and frustration at the divide. A final huge thank you goes to my parents for allowing, financing, and supporting my decision to study abroad in Costa Rica It was an experience I will never forget. LITERATURE CITED Anderson, S. D. 1982 Comparative population ecology of Peromyscus mexicanus in a Costa Rican wet forest. Ph. D dissertation, University of Southern California, Los Angeles, CA. Enquist, C. A. F. 2002 Predicted regional impacts of climate change on the geographical distribution and di versity of tropical forests in Costa Rica. Pp. 519 534. Journal of Biogeography. Blackwell Science Ltd. Fleming, T. H. 1977 Response of two species of tropical heteromyid rodents to reduced food and water availability. Journal of Mammology. 58:10 6 . Found in Costa Rican Natural History D. H. Janzen ed. University of Chicago, Chicago. USA. Fleming, T. H. 1983 Heteromys desmarestianus Raton Semiespinosa, Spiny Pocket Mouse pp. 474 475 In: Costa Rican Natural History. D. H. Janzen ed.. The U niversity of Chicago, Chicago. USA. Hayes , M. and R. LaVal. 1989 . The Mammals of Monteverde: An annotated check list to the mammals of Monteverde. Tropical Science Center: San Jose, Costa Rica. Hartshorn, G. S. 1983 . Plants. Pp. 118 25 In: Costa Rican Natural History. D. H. Janzen ed. The University of Chicago, Chicago, USA. Holdridge, L. R. 1942 Life Zone Ecology Revised Edition. T ropical Science Center, San Jos é , Costa Rica. Janzen, D. H. and D. E. Wilson 1982 pp. 427 in Costa Rican N atural History. D. H. Janzen ed.. The University of Chicago, Chicago, USA. McCain, C. M. 2004 The mid domain effect applied to elevational gradients: species richness of small mammals in Costa Rica. Pp. 19 31. Journal of Biogeography. Blackwel l Publishing Ltd.

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9 Nowak, R. M. AND J. L. Paradiso. 1983 Walkers Mammals of the World. 4 th ed. Vol. II. John Hopkins University Press, Baltimore and London. Pounds, J. A., M. R. Bustamante, L. A. Coloma, J.A. Consuegra, M.P.L. Fogden, P. N. Foste r, E. L. Marca, K. L. Masters, A. Merino Viteri, R. Puschendorf, S. R. Ron, G. A. Sanchez Azofeifa, C. J. Still, and B. E. Young. 2006 Widespread amphibian extinctions from epidemic disease driven by global warming. Pp. 161 167. Nature. V. 439. Natu re Publishing Group. ______. J. A. 2000 Amphibians and Reptiles. In Monteverde: Ecology and Conservation of a Tropical Cloud Forest. Eds. Nadkarni, N. M. and N. T. Wheelwright, Oxford University Press, New York. Rehmeier, R. L. 1996 . An examinatio n of vertical stratification and niche partitioning in a cloud forest rodent community. CIEE, Spring semester. Reid, F. A. 1997 . A Field Guide to the Mammals of Central America & Southeast Mexico. pp. 197 198; 206 207; 221; 223 224; 232 233. Oxford U niversity Press, New York, New York 10016. Rothman, A. W. 1999 Effects of Climate Change and Elevation on Small Rodent Communities in Monteverde, Costa Rica. CIEE, Spring semester. Timm, R. M., and R. K. LaVal. 2000 Mammals. In Monteverde: Ecolog y and Conservation of a Tropical Cloud Forest. pp. 233 244. Nadkarni, N. M. and N. T. Wheelwright eds. New York: Oxford University Press. Velez Zuazo, X., L. Lawson, B. Timm, M. Ferro, E. Kuprewicz, and R. Weaver. 2005 comparison of diversity and abundance of mice in two types of forest during the dry and wet season. In OTS 2005 3. APPENDIX Natural History of Species Peromyscus nudipes Cloud Forest Deer Mouse has a large distribution and is especially abundant in semideciduous, secondary f orest, and along streams Reid 1997. It is largely terrestrial but can climb well, and in a study conducted by Rehmeier 1996, it was found that they are surprisingly more arboreal than originally thought. Burrows can be found in open areas of the fore st floor, as well as in the roots of trees or under logs Reid 1997. It is a generalist species, and extremely abundant in Monteverde Nowak and Paradiso 1983; Hayes and LaVal 1989 Fig. 6. Heteromys desmarestianus Forest Spiny Pocket Mouse, is di stributed from Mexico through Central America to Northwestern Colombia, and ranges between the lowlands and 2400 meters in elevation Reid 1997. According to Janzen 1983, its usual habitat is montane or tropical rain forest. It is primarily a granivor e and uses its external fur lined cheek pouches to travel with seeds Janzen 1983. Much like P. nudipes , it burrows in open areas on the forest floor and under roots of trees. This species was especially susceptible to food and water deprivation, which is consistent with previous studies Fleming 1977. Within two or more days of water deprivation, individuals can lose too much weight and die. After a limited diet of only sunflower seeds, as tested by Fleming 1997, individuals can also lose weight qui ckly and die when about 20% of their weight has been lost. Even after only one night in the trap, I observed that most H. desmarestianas were in very poor health when discovered in the morning.

PAGE 10

10 Although they have a large distribution, specialized eating habits may make them vulnerable to changes in seed and water availability Fig. 9. Scotinomys teguina Alstons Singing Mouse ranges from 900 to 2900 meters in elevation, and is common and abundant in cloud forest, forest edge and grassy clearings. It is generally diurnal and typically most active in the morning. S. teguina is mostly terrestrial and uses runways and well known paths through grass and under logs. It has been found from one to three meters above the ground after feeding on the nectar o f Blakea austin smithii , a Melastome. It is mostly insectivorous -80% of its diet consists of insects -but will also feed on seeds, nectar and fruits. An interesting characteristic of this species is that both sexes will frequently make an insect like, trilling call that can last up to 10 seconds Reid 1997. Due to its insectivorous nature, S. teguina could be negatively affected by a decrease in insect diversity due to a change in environment and temperature Fig. 5. Oryzomys albigularis Montane Rice Rat is found throughout the mountains of Costa Rica, from 1000 3000 meters in elevation. It is common in mature, evergreen, and highland forests and is often found along streams, on wetter slopes and ridges, and near mountaintops. O. albigularis sw ims well, but is mainly terrestrial and can be trapped on the ground near fallen logs and on low, moss covered branches Reid 1997. Although it has a widespread metapopulation, it has a specific habitat among the mountains of Costa Rica, which may make it vulnerable to changes in habitat and climate. Its metapopulation size is much more limited than P. nudipes , so it may be a more specialist species than the deer mice Fig. 4. Cryptotis gracilis Talamancan Small Eared Shrew is a very small sorici d mammal in the order Insectivora. It ranges between 1800 and 3400 m in the Central and Talamancan mountains of Costa Rica. Although is fairly common in highland oak forest and paramo, this order is poorly represented in Costa Rica Reid 1997 Fig. 8. Rattus rattus Roof Rat has been introduced worldwide, but in this area it is extremely uncommon Hayes and Laval 1989. It is found in and around human habitations -both in cities and rural areas -and less commonly in forest or at forest edge. It i s mainly nocturnal and climbs well. Its diet includes grain, fruit, and garbage, and is an extremely prolific breeder. Due to its adaptability, it may kill or displace native species Reid 1997 Fig. 7. Figure 4. Oryzomys albigularis F. Muridae Figure 5. Scotonomys teguina F. Muridae

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11 Figure 6. Peromyscus nudipes F. Muridae Figure 7. Rattus Rattus?? Unknown juvenile. F. Muridae Figure 8. Cryptotis gracilis F. Soricidae Figure 8. Cryptotis gracilis F. Soricidae Figure 9. Heteromys desmarestianas F. Hetermyidae


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