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Articles 1 - 22 of 22
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Effects Of Habitat Disturbance On The Territorial Response Of The Gray-Breasted Wood-Wren, Henicorhina Leucophrys, December 2003, Blake Audsley
Effects Of Habitat Disturbance On The Territorial Response Of The Gray-Breasted Wood-Wren, Henicorhina Leucophrys, December 2003, Blake Audsley
Tropical Ecology and Conservation [Monteverde Institute]
Habitat fragmentation and disturbance have become integral aspects of the neotropical landscape, impacting a variety of ecological factors. Here I attempt to quantify the relationship of bird territory size and habitat disturbance by observing the effects of habitat disturbance on avian response to conspecific playback in the Gray-breasted Wood-wren, Henicorhina leucophrys. Mean distance traveled to follow playback increased along a gradient of increasing disturbance (F = 4.435, p-value = .0165, s.d. = 27.256; 47.283; 49.094). Edge habitat birds showed significantly greater response than birds in primary and secondary growth (p-values = 0.0051; 0.0479). Variation in response also differed between habitats. …
Reproduction Of Besleria Princeps In Monteverde Cloud Forests, December 2003, Michelle Murphy
Reproduction Of Besleria Princeps In Monteverde Cloud Forests, December 2003, Michelle Murphy
Tropical Ecology and Conservation [Monteverde Institute]
The purpose of this study was to show the occurrence of asexual versus sexual reproduction in lower premontane cloud forest, on the Atlantic slope and the Pacific slope of the Tilarán Mountain range near the Monteverde Biological Station. Eight hundred plants, 400 on the Atlantic slope and 400 on the Pacific side, were examined at their roots for fragmentation and seeding. The elevations of each slope and a comparison of the two slopes were examined using a chi-squared two-way contingency test. The results showed that asexual reproduction (fragments) is more common in Besleria princeps than sexual reproduction (from seeds). The …
An Introductory Lesson Plan To The Flora And Fauna Of The Monteverde Cloud Forest, December 2003, Amanda Rocklet
An Introductory Lesson Plan To The Flora And Fauna Of The Monteverde Cloud Forest, December 2003, Amanda Rocklet
Tropical Ecology and Conservation [Monteverde Institute]
The result of this project is a mini-course lesson plan which can be used at the Cloud Forest School-Centro de Educación Creativa (C.E.C,). The mini course lesson plan will be used in seventh and eighth grade classes to teach the local taxa of Monteverde. Enclosed are six Power Point presentations, six interactive activity plans, six field guides, and a list of teacher resources. I expect this mini course to reinforce the C.E.C.'s environmental education curriculum while also taking into account teacher turnover and lack of resources.
Effect Of Climate Change On Four Species Of Azteca In Monteverde, Puntarenas, Costa Rica, December 2003, Paul Mazzei
Effect Of Climate Change On Four Species Of Azteca In Monteverde, Puntarenas, Costa Rica, December 2003, Paul Mazzei
Tropical Ecology and Conservation [Monteverde Institute]
There has been extensive, research in the Monteverde area that has shown that both the abundance and range of lizards, amphibians, and birds have been affected global warming (Pounds (1999). Although there have been studies showing changes in abundance of arctic and temperate invertebrates, there have not been any studies that have shown invertebrate response to climate change in Monteverde. The four species of Azteca ants (xanthochroa, constructor, coeruleipennis, and alfari) were collected along roads in Monteverde and nearby Santa Elena and San Luis at elevations ranging from 700-1500m. The altitudinal ranges from this study were compared to ranges obtained …
Hummingbird Size, Pollen Load And Pollination Efficiency, December 2003, Andrew Gapinski
Hummingbird Size, Pollen Load And Pollination Efficiency, December 2003, Andrew Gapinski
Tropical Ecology and Conservation [Monteverde Institute]
Pollinators are an important selective agent and play a role in the evolution of certain floral characteristics (Fenster, 1991). This is often the case with flower corollas, which have closely coevolved with the length and curvature of the bill or tongue of its pollinators (Stiles 1989) The purpose of this study was to determine the specificity of the coevolution between hummingbirds as pollinators and the species on which they forage. I also hope to examine the bill length- body size relationship, pollen loads and their placements. I hypothesize that short-billed hummingbirds will carry pollen from plant species with short corollas, …
Microhabitat Use And Escape Behavior Of Male, Female And Juvenile Norops Oxylophus (Polychrotidae), December 2003, Nathan Dappen
Microhabitat Use And Escape Behavior Of Male, Female And Juvenile Norops Oxylophus (Polychrotidae), December 2003, Nathan Dappen
Tropical Ecology and Conservation [Monteverde Institute]
The intraspecific distributions of microhabitats in territorial lizard species is determined largely by differing behavior among sexes and age classes. In this project I study a population of Norops oxylophus along the Río Alondra of the San Luis Valley towards the end of the rainy season. I caught individuals, recording their age, sex, size, perch substrate and location, and escape method. I found that adult males prefer to be perched on live tree branches overhanging the water; the larger the individual, the higher he is above the stream. Juveniles are found to inhabit lower areas along the stream banks. Males …
Spatial Distribution Patterns Of Mistletoe (Antidaphne Viscoidea: Eremolepidaceae, And Phoradendron Undulatum: Viscaceae) On Psidium Guajava (Mrytaceae) In Monteverde, Costa Rica, December 2003, Matthew Greenfield
Tropical Ecology and Conservation [Monteverde Institute]
Spatial distributions of mistletoe are noticeably clustered but unexamined in Monteverde, Costa Rica. To better understand their spatial structure, I examined the dispersion of two species of epiphytic mistletoe (Antidaphne viscoidea: Eremolepidaceae and Phoradendron undulatum: Viscaceae) within and between host trees. Six sites on one hill in Cañitas, Costa Rica were surveyed for data relating to dispersion structure (nearest neighbor distance and frequency within host trees). Additional study was done on the spatial dispersion on the host tree Psidium guajava, and it was found to have clustered dispersions. Indices of dispersion and tests comparing observed results to Poisson distributions showed …
Tree Size And Habitat Effects On Stream Gall Abundance In Conostegia Oerstediana (Melastomataceae), May 2003, Priya Shashidharan
Tree Size And Habitat Effects On Stream Gall Abundance In Conostegia Oerstediana (Melastomataceae), May 2003, Priya Shashidharan
Tropical Ecology and Conservation [Monteverde Institute]
The moth Mompha sp. (Coleophoridae, Lepidoptera) is known to induce a stem gall on the tree Conostegia oerstediana (Melastomataceae). There is little known about the distribution and abundance of galls. This study tested the difference in stem gall abundance between varying tree sizes and between two different habitats- pasture and secondary forest. Trees from each habitat were sampled and measured for diameter at breast height (DBH), height, number of branches, and number of galls. A significant difference was found between pasture and forested areas (unpaired t-test, p < 0.0001), with pasture trees having more galls. No relation was found relating tree size (DBH, height, number of branches) to gall abundance. I conclude from these results that tree size is not directly related to stem gall abundance. Instead, differences in habitats, such as predator and parasite abundance and host density, may be important factors that influence gall abundance.
Resource Partitioning Between Trigona Fulviventris And Scaptotrigona Mexicana With Overlapping Flight Ranges, May 2003, Michelle H. Averbeck
Resource Partitioning Between Trigona Fulviventris And Scaptotrigona Mexicana With Overlapping Flight Ranges, May 2003, Michelle H. Averbeck
Tropical Ecology and Conservation [Monteverde Institute]
The theory of resource partitioning predicts that congeneric species are allowed to coexist by a division of the available resources. This study looks at the possibility of resource partitioning between Trigona fulviventris and Scaptotrigona mexicana on fine temporal scales in Cloud Forest habitat, a region in which stingless bee pollen diets has not been extensively studied. Workers from one T. fulviventris and one S. mexicana nest, located 200 m apart, were studied synchronously over six days. Capture-mark and release experiments verified that the foraging areas of these two nests indeed overlap. Of the 14 morphotypes of pollen brought in by …
The Role Of Height And Flower Symmetry In Bat Pollination Of Mucuna Urens (Papilionaceae), May 2003, Callie Vincent
The Role Of Height And Flower Symmetry In Bat Pollination Of Mucuna Urens (Papilionaceae), May 2003, Callie Vincent
Tropical Ecology and Conservation [Monteverde Institute]
The flowers of plants in the tropics have evolved mechanisms that attract bats and ensure that pollination is deposited on the bat for transfer to the next flower (Altringham 1996). In particular, a recent study has shown that flowers in the Mucuna genus attract bats using an acoustic nectar guide (vonHelverson and vonHelverson 1999). In order to test additional factors that could possibly play a role in the pollinator-plant relationship involvingMucuna, inflorescence height, infructescence height, and flower symmetry were studied for fiveMucuna urens patches in the Monteverde (Puntarenas, Costa Rica) cloud forest. A simple regression showed no significant relationship between …
Colony Size And Its Effect On Forager Polymorphism In Atta Cephalotes (Hymenoptera, Formicidae), March 2003, Matthew R. Wallrath
Colony Size And Its Effect On Forager Polymorphism In Atta Cephalotes (Hymenoptera, Formicidae), March 2003, Matthew R. Wallrath
Tropical Ecology and Conservation [Monteverde Institute]
Atta cephalotes or leaf-cutting ants (Hymenoptera, Formicidae) exhibit strong polymorphism over the life span of a single colony. This polymorphism effects foraging efficiency and is linked to overall social complexity. In this study, I quantified the degree of variance in head size and femur length in six colonies, as well as presence of a soldier class, and compared these results to the relative size of each nest as determined by a survey of foraging intensity. It was found that variance in the head and femurs and the presence of soldiers was significant different between small and large colonies, and this …
Niche Partitioning And Overlap In A Cloud Forest Between Two Neotropical Warblers (Parulidae), March 2003, Evan M. Adams
Niche Partitioning And Overlap In A Cloud Forest Between Two Neotropical Warblers (Parulidae), March 2003, Evan M. Adams
Tropical Ecology and Conservation [Monteverde Institute]
The types of niche partitioning between two congener bird species Myioborus miniatus and M. torquatus (Parulidae) were studied in premontane wet and rain forest in Monteverde, Costa Rica. An altitudinal distribution showed that M. niniatus was found at an average height of 1568m and M. torquatus at 1612m. Foraging behavior was also different between the two species with M. miniatus foraging at an average height of 4.6m and M. torquatus at 7.2m off the ground. These findings indicate that there is a large amount overlap in altitudinal distribution and foraging height between the two species. Stronger partitioning with less overlap …
Plant Preference And Camouflage In Phasmid Morphospecies, March 2003, Jackie Prange
Plant Preference And Camouflage In Phasmid Morphospecies, March 2003, Jackie Prange
Tropical Ecology and Conservation [Monteverde Institute]
Phasmids in the tropical and temperate zones are known to exhibit both polyphagous and monophagous behavior. Because more plants are better protected in the tropics, the expected number of host-plant specific insects, including Phasmids, should be higher. The diets of seven Phasmid morphospecies and a nymph group in the families Psuedophasmatidae and Phasmatidae of the Monteverde cloud forest, Puntarenas, Costa Rica, were studied. Results showed that these morphospecies consumed different amounts and different plant species (two-way ANOVA, P < 0.0001). Amount consumed increased with size as measured by tibia length. All morphospecies were polyphagous, but had differing plant preferences. Diet composition and breadth depended on morphospecies. Nymphs, however, were monophagous on Conostegia oerstediana. This study also investigated Phasmid camouflage. Phasmids of three color classes showed no significant difference in preferred resting substrate (two-way ANOVA, P < 0.0001). Phasmids most likely rely on other defense mechanisms, such as body shape and behavior, for protection.
Water Quality And Lichen Coverage In Monteverde Streams, March 2003, Stephanie Payne
Water Quality And Lichen Coverage In Monteverde Streams, March 2003, Stephanie Payne
Tropical Ecology and Conservation [Monteverde Institute]
This study examined lichen abundance and water quality in six streams in Monteverde, Costa Rica. By estimating lichen coverage on rocks over a 90 m transect, mean lichen coverage per stream was measured. Water quality was estimated by measuring temperature, dissolved oxygen concentration, pH, turbidity, nitrogen and phosphorous levels at each stream. Mean lichen coverage varied between each site, showing that the Quebrada Sucia had the smallest lichen coverage and the Quebrada Máquina had the highest lichen coverage. A significant positive correlation was found between percent lichen coverage and total dissolved oxygen concentration. There are at least four possible explanations …
The Causes And Effects Of Nest Clustering In Colonies Of The Chestnut-Headed Oropendola (Psarocolius Wagleri), March 2003, Jason Fisher
The Causes And Effects Of Nest Clustering In Colonies Of The Chestnut-Headed Oropendola (Psarocolius Wagleri), March 2003, Jason Fisher
Tropical Ecology and Conservation [Monteverde Institute]
Colonies of nesting birds are often subdivided into clusters of nests; the causes and effects of these clusters have profound impacts on the breeding strategies of colonial nesting birds. Five colonies of a Neotropical colonial nesting bird, the Chestnut-headed Oropendola (Psarocolius wagleri), were studied to identify trends in male and female intersexual competition, mating strategy, and brood parasitism in relation to colony and cluster size. The results were compared with data from studies by Webster (1994a, b) for another colonial nester, the Montezuma Oropendola (Psarocolius montezuma), which is known to use female-defence polygyny. The comparisons showed that while both the …
Biological Responses Of Platystele Microtatantha And Specklinia Aristata (Orchidaceae) To Climate Change In Monteverde, Costa Rica, March 2003, Eleonore Wesserle
Biological Responses Of Platystele Microtatantha And Specklinia Aristata (Orchidaceae) To Climate Change In Monteverde, Costa Rica, March 2003, Eleonore Wesserle
Tropical Ecology and Conservation [Monteverde Institute]
The lifting of the cloud bank due to climate change in the Monteverde cloud forest has already caused discernible effects on the dry season mist regime. Epiphytes, including the most prevalent family of epiphytes, Orchidaceae, may serve as a useful indicator group of climate change. This study sought to fill the gap in knowledge about orchidaceous epiphytes and climate change by testing the response of the pleurothallid orchids Platystele microtatantha and Specklinia aristata to supplemental mist treatments simulating 1970s mist frequencies. Two sites were studied: P. microtatantha growing on an orchid frame and P. microtatantha and S. aristata individuals growing …
Algae As Biological Indicators Of Stream Water Quality In Monteverde, Costa Rica, March 2003, Andrea Buckman
Algae As Biological Indicators Of Stream Water Quality In Monteverde, Costa Rica, March 2003, Andrea Buckman
Tropical Ecology and Conservation [Monteverde Institute]
Water quality is an issue of increasing importance as the growing population depletes and contaminates the Earth's natural resources. One example of this is in Monteverde, Costa Rica, where wastewater is directly discharged from homes and businesses into the many streams in the area, affecting the ecosystem within the streams. Runoff from the many farms and pastures that are treated with highly concentrated pesticides and fertilizers can also affect the natural freshwater ecosystems by adding nutrients and toxins. Seven streams in the Monteverde area were analyzed in order to determine if algae morphospecies can be used as reliable indicators of …
Effects Of Caste Structure On Nasutitermes Spp. (Isoptera) Hindgut Protozoan Populations, March 2003, Ruth Healey
Effects Of Caste Structure On Nasutitermes Spp. (Isoptera) Hindgut Protozoan Populations, March 2003, Ruth Healey
Tropical Ecology and Conservation [Monteverde Institute]
Evolutionary development of eusocial behavior in termite populations may be due to their symbiotic interaction with the protozoa that live in the hindgut and aid in cellulose digestion (Wilson 1971). In particular, the way in which protozoa are passed between individuals of different castes and the resulting variance in diversity could have led to the development of social interactions and specialization within castes over evolutionary time. This study looked at the hindgut composition of Nasutitermes spp. among three different castes across multiple nests to determine if a caste-dependent gradient of hindgut faunal diversity exists. Castes from six nest sites were …
Species Diversity, Activity, And Behavioral Variation In Fireflies (Coleoptera: Lampyridae) Along An Elevational Gradient, March 2003, Emily J. Stirr
Species Diversity, Activity, And Behavioral Variation In Fireflies (Coleoptera: Lampyridae) Along An Elevational Gradient, March 2003, Emily J. Stirr
Tropical Ecology and Conservation [Monteverde Institute]
Three aspects of firefly ecology were investigated including species diversity, activity and behavior of llampyrid species. Lampyrid species diversity was measured along an elevational gradient at five different sites (950m, 1100m, 1200m, 1450m, 1550m). Activity was measured along the same gradient between 6:00 PM and 8:45 PM. Behavioral diversity was studied in the context of species responses to disturbance by a simulated predator. Seven different species were collected including specimens of Aspisonia sp. and Photuris sp. Species diversity was found to be lowest at mid elevations and tended to increase at the outer ends of the gradient. Diversity was found …
Advantageous Development Of Buttresses Displayed In Quercus Spp., March 2003, Mariel Platt
Advantageous Development Of Buttresses Displayed In Quercus Spp., March 2003, Mariel Platt
Tropical Ecology and Conservation [Monteverde Institute]
The many hypotheses aimed at describing the physiological, morphological, environmental forces contributing to buttress development have not clearly shown definitive evidence regarding what selective forces are responsible for buttress formation. One hypothesis that has little documented research available is that the presence of buttresses allows for an increased abundance of organic matter and inhibits nutrient leaching from the soil, thus providing the tree with a greater quality soil for localized growth. Twenty-five different soil samples were collected and analyzed for potassium, nitrogen, phosphorus, and pH from both the base of buttressed Quercus spp. and a control site in the cloud …
Diversity And Species Breadth Of Carrion Insect Communities Along An Altitudinal Gradient, March 2003, James Dugan
Diversity And Species Breadth Of Carrion Insect Communities Along An Altitudinal Gradient, March 2003, James Dugan
Tropical Ecology and Conservation [Monteverde Institute]
Detritivores play a crucial role in nutrient cycling within tropical forests by returning nutrients to the ecosystem. The purpose of this study was to inventory carrion feeding insect communities and show the change in insect diversity along an altitudinal gradient. Five sites were visited every 200m along the gradient from 800m to 1600m using carrion as bait to attract insects. A total of 1507 individuals were collected, representing 21 species. Six of the ten diversity comparisons using a variation of the Shannon- Weiner Diversity Index and modified t-tests were significantly different (p < 0.05). The number of individuals was found to decrease as elevation increased (simple regression, p = 0.0158, r2 = 0.01). It is believed that the lower elevations harbor a higher diversity and species richness due to unfavorable conditions at the higher elevations.
Effects Of Habitat Type On Predation Rates, March 2003, Erin Wilichowski
Effects Of Habitat Type On Predation Rates, March 2003, Erin Wilichowski
Tropical Ecology and Conservation [Monteverde Institute]
High rates of habitat alteration increase the effects of fragmentation and creation of pasture. Degraded habitat can negatively affect predator abundance and hence predation. In this study, variation in predation rates between closed forest, open forest, and pasture were assessed for a matrix of degraded tropical premontane moist forest in Costa Rica. In order to compare predation rates in the different habitat types, non-toxic clay caterpillars were made, placed on understory leaves, and then rates of predation in each habitat type were determined. This study focused on three types of predators, insects, birds, and rodents, with insects as the most …