USF Libraries

Flower Color and Shape Variation on an Elevational Gradient

MISSING IMAGE

Material Information

Title:
Flower Color and Shape Variation on an Elevational Gradient
Translated Title:
Marlene ( )
Physical Description:
Book
Language:
English
Creator:
Fraser, Sarah

Subjects

Subjects / Keywords:
Flowers   ( lcsh )
Pollination   ( lcsh )
Plants--Effect of altitude on   ( lcsh )
Costa Rica--Puntarenas--Zona de Monteverde--Monteverde   ( lcsh )
Flores
Polinización
Marlene
Costa Rica--Puntarenas--Zona de Monteverde--Monteverde
Tropical Ecology Fall 2003
Ecología Tropical Otoño 2003
Genre:
Reports   ( lcsh )
Reports

Notes

Abstract:
Many flowering plant species have coevolved with pollinator species to form fairly specialized pollination systems that involve both color and shape of flowers, for example red and orange tubularshaped flowers are attractive to hummingbirds and white, yellow, and blue disk and head shaped flowers are attractive to insects. In Monteverde, Puntarenas, Costa Rica an elevational gradient of pollinator animals has been observed such that cool temperatures in the high altitude regions limit insect activity to low elevations, thereby leaving the high elevation pollination to hummingbirds, leading to the hypothesis that flower color and shape patterns would reflect this pollinator gradient. A patch of continuous forest on the Pacific slope of the Monteverde area was divided into 50m elevational bands from 1250m to 1400m and from 1550m to 1750m and flowering plants censused for color and shape along trails in those bands. Orange and red tubular flower were significantly more abundant in the high elevation bands and blue, white, and yellow/green disk and aster flowering plants were significantly more abundant at the lower elevations. These differences in abundance along the elevational gradients reflect the pattern of hummingbird presence domination at high elevation and insect domination at low elevation.
Abstract:
Una porción grande de florecer la especie de planta ha coevolucionado con la especie polinizadora en tanto que ellos habido especializado sistemas de polinización en cual o pocos polinizadora, eso está en el mismo grupo taxonómico (E.G. los colibrís), poliniza una especie de planta. Esta especialización puede contribuir a un declive del elevational del color de flor y forma que corresponder con el declive de elevational en la especie polinizadora que resulta de nicho que divide debido a factores no bióticos de hábitat. En Monteverde, Puntarenas, Costa Rica un declive de elevational de animales polinizadoras se ha observado tanto que refrescado las temperaturas en las regiones altas de la altitud en la actividad Pacífica de insecto de límite de cuesta a elevaciones bajas, con lo cual saliendo la polinización alta de la elevación a colibrís y lo fue formado una hipótesis ese color de flor y las pautas de la forma reflejarían este declive. El bosque continuo de la cuesta Pacífica del área de Monteverde se dividió en 50 bandas de elevational M de 1250 M -1400M y 1550 M – 1750 M y florecer censused de plantas para el color y la forma por rastros en esas bandas. Tanto el color como la forma se vieron para estar difiriendo apreciablemente de sobra por el declive de elevational y de tal manera de reflejar como la pauta de la dominación de la presencia del colibrí en la elevación alta a la dominación del insecto en la elevación baja.
Language:
Text in English.
General Note:
Digitized by MVI

Record Information

Source Institution:
University of South Florida Library
Holding Location:
University of South Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
usfldc doi - M39-00446
usfldc handle - m39.446
System ID:
SFS0036391:00001


This item is only available as the following downloads:


Full Text

PAGE 1

Flower color and shape variation on an elevational gradient Sarah Fraser Department of Biology, Texas Tech University _____________________________________________________________________________________ ABSTRACT Many flowering plant species have coevolved with pollinator species to form fairly specialized pollination systems that involve both color and shape of flowers, for example red and orange tubular shaped flowers are attractive to hummingbirds and white, yellow, and blue disk and head shaped flowers are attractive to insects. In Monteverde, Puntarenas, Costa Rica an elevational gradient of pollinator animals has been observed such that cool temperatures in the high altitude regions limit insect activity to low elevations, thereby leaving the high elevation pollination to hummingbirds, leading to the hypothesis that flower color and shape patterns would reflect this pollinator gradient. A patch of continuous forest on the Pacific slope of the Monteverde area was divided into 50m elevational ban ds from 1250m to 1400m and from 1550m to 1750m and flowering plants censused for color and shape along trails in those bands. Orange and red tubular flower were significantly more abundant in the high elevation bands and blue, white, and yellow/green disk and aster flowering plants were significantly more abundant at the lower elevations. These differences in abundance along the elevational gradients reflect the pattern of hummingbird presence domination at high elevation and insect domination at low elevat ion. RESUMEN Una porcin grande de florecer la especie de planta ha coevolucionado con la especie polinizadora en tanto que ellos habido especializado sistemas de polinizacin en cual o pocos polinizadora, eso est en el mismo grupo taxonmico (E.G. los colibrs), poliniza una especie de planta. Esta especializacin puede contribuir a un declive del elevational del color de flor y forma que corresponder con el declive de elevational en la especie polinizadora que resulta de nicho que divide debido a f acto res no biticos de hbitat. En Monteverde, Puntarenas, Costa Rica un declive de elevational de animales polinizadoras se ha observado tanto que refrescado las temperaturas en las regiones altas de la altitud en la actividad Pacfica de insecto de lmite de cuesta a elevaciones bajas, con lo cual saliendo la polinizacin alta de la elevacin a colibrs y lo fue formado una hiptesis ese color de flor y las pautas de la forma reflejaran este declive. El bosque continuo de la cuesta Pacfica del rea de Monte verde se dividi en 50 bandas de elevational M de 1250 M 1400M y 1550 M 1750 M y florecer censused de plantas para el color y la forma por rastros en esas bandas. Tanto el color como la forma se vieron para estar difiriendo apreciablemente de sobra por el declive de elevational y de tal manera de reflejar como la pauta de la dominacin de la presencia del colibr en la elevacin alta a la dominacin del insecto en la elevacin baja. INTRODUCTION Many flowering plants are pollinated by a variety of anim als which are attracted in several different ways. Pollination systems are generally characterized by one or few related plant species having one or few

PAGE 2

related pollinator species. For instance, in the Neotropics, many related orchids rely upon Euglossine bees, whereas plants of the family Gesneriaceae rely upon hummingbirds (Ba wa 1990). Accordingly, there is a particular suite of floral traits, including both colors and shapes that make the plants adapted to their gradient pollinators, and vice versa. The suite of floral traits displayed by a plant, along with the re or less specialized in their syndrome, or why certain syndromes are more or less common (Bawa 1990; Young and McDonald 2000). This study focuses on pollination syndromes as related to an elevational gradient in the Neotropics Elevation can be seen to influence the frequency of pollination systems in that flight in cool, cloudy conditions (as seen at high elevations) is easier for some animals than others (Murray et al 2000). This stratification can be seen as a method of avoiding direct competition bet ween nectarivorous animals as nectar resources are distributed between competing animal species according to the habitat preferences for those species. Temperature is a determinate factor in where a pollinating animal species lives as species differ from one another in their temperature tolerances and temperature optima. In the Monteverde area, Costa Rica, the Pacific slope of the Cordillera de Tilarn is made up of several Holdridge life zones, including premontane wet forest, lower montane wet forest, an d lower montane rainforest (Haber 2000). There are warmer average temperatures at lower elevations and cooler average temperatures at higher elevations. These temperatures influence pollinator stratification in that cool temperatures limit the activity and metabol ic rates of insects that depend on nectar (Murray et al. 2000). In response, insects generally stay at lower elevations. Conversely, hummingbirds are not limited in activity by the cool temperatures of high elevation, and can live successfully at h igh elevations. Flower morphology has probably coevolved with pollinator species (Murray et al. 2000) so the distribution of the color and shape of flowers should reflect any niche partitioning among pollinators of Monteverde flora. As cooler temperatures dictate lower metabolic rates and activity in insects, hummingbirds become extremely important pollinators of upper elevation flowering plants (Stiles and Skutch 1989). Flowers pollinated by hummingbirds are generally red, orange, and tubular and are main ly found in epiphytes, shrubs, vines, and treelets while bees and other insects are known to visit a variety of flower colors and shapes on herbs, shrubs, and trees. Often these flowers are flat, dislike, or have a very 1999). The flowers between 1250m and 1750m on the Pacific slope of the Monteverde area should correspond with the pollinator distributions such that there should be a higher frequency of p lants with red or orange tubular flowers at upper elevations and a higher frequency of small, white, yellow, or blue dis like flowers at lower elevations. METHODS Observations were made along 50m elevational bands in Monteverde, Puntarenas, Costa Rica al ong the Pacific slope and in the continuous forest of the Estacin Biolgica Monteverde (EBM), Monteverde Cloud Forest Preserve (MCFP), and the Bosque Eterno de los Nios (BEN) from October 19 November 16, 2003. Elevations covered were 1250m 1400m (BEN) and 1550m 1750m (EBM and MCFP) and the elevational bands were divided along trails every 50m of elevational change (Figure 1). Flowering plants were observed up to 10m on either side of a trail and from ground level to canopy. Trails used were Sendero Principal of EBM, Senderos Nuboso, Pantanoso, and Chomogo of MCFP, and Senderos Murcilago, Calandria, and del Tigre in the Bajo del Tigre area of BEN. Data taken included numbers of individual flowering plants per species and the color and shape of the f lowers. Observations were made by sight and with the aid of binoculars. The plants were photographed for identification (if possible) as well as for classification of color and shape.

PAGE 3

on dicotyledon and monocotyledon flower shapes (1993) and with a few added categories as well. The shape categories flowers with a head or with a he as a small corolla that an as a labellum; that did not fit into any of the other categories but for which there was only one species. Color categories were blue, yellow/green, orange, pink/purple, red, and white and plants were categorized by the most dominating color found on the flower. Data were analyzed using Chi s quared tests and Contingency tables. RESULTS Sixty four species of flowering plants were observed and flowers were classified by color and shape. Color categories analyzed included blue, yellow/green, orange, red, and white and shape categories analyzed were aster, disk, and tubular. Orange and red flowers were mainly tubular in shape while the majority of white, yellow green, and blue flowers were disk or aster shaped (Figure 2). Color Data: There were statistically significant differences between colo rs along the elevational bands (X 2 = 765. 636, df = 24, p value < 0.0001; Figure 2). Specifically, blue flowers were significantly more abundant and orange flowers significantly less abundant than expected from 1250m 1300m. Orange flowers were significan tly more abundant than expected from 1650m 1700m. From 1700m 1750m, orange flowers were again significantly more abundant and blue flowers significantly less abundant than expected. Table 1. Plant flower color frequency data 1250m 1300m 1350m 1550m 1 600m 1650m 1700m Totals Blue 161 0 35 0 0 0 0 196 Ylw/Grn 2 1 22 4 4 9 5 47 Orange 22 2 5 19 8 67 111 234 Red 13 19 2 27 28 21 64 174 White 26 17 50 38 17 7 5 160 Totals 224 39 114 88 57 104 185 811 Shape Data: There were also significant differences between shapes of flowers found in each band (X 2 = 411. 386, df = 12, p value < 0.0001 ; Figure 4). For 1350m 1400m, asters were significantly more abundant and tubular flowers significantly less abundant than expected. On the other hand, tubu lar flowers were significantly more abundant than expected between 1700m and 1750m. Table 2. Plant flower shape frequency data

PAGE 4

1250m 1300m 1350m 1550m 1600m 1650m 1700m Totals Aster 28 0 57 2 0 2 0 89 Disk 23 12 34 13 5 6 5 98 Tubular 171 24 2 65 58 92 185 597 Totals 222 36 93 80 63 100 190 784 Discussion I hypothesized that, due to specialization in pollination systems and differences in physiological tolerances among pollinators, red and orange tubular flowers (referred to as hummingbird flowers from here on) would be found in higher abundance in the upper elevational ranges and in lower abundance in the lower elevations. White, yellow, and blue disk like or short corolla/landing platform flowers (referred to bee/insect flowers from here on) woul d be found in high abundance at lower elevations and in low abundance at high elevations. The results support this hypothesis in that, in the ranges of 1250m 1400m and 1550m 1750m, hummingbird flowers were observed with significantly higher abundance th an bee/insect flowers while bee/insect flowers were found with highest abundance from 1250m 1300m. There are two possible explanations for these results. First hummingbird flowers in the lower montane wet and rainforest life zones of Monteverde (1550m 1750m) have an annual flowering peak in the months of October to November while bee/insect flowers (trees and shrubs specifically) generally flower more during the dry season (January to April) (Haber 2000). Also in the premontane wet forest zone (1250m 1400m) hummingbird flowers tend to bloom more during the dry season (Haber 2000). These patterns could mean that the trends I observed were due simply to seasonal flowering rather than an elevational gradient corresponding with pollinator difference s. However, since at least 10% of flowering plant species are blooming during any month of the year (Haber 2000), a representative portion of the total hummingbird and bee/insect flowers were most likely present. It would be interesting to repeat this stud y during the dry season to determine whether the flower distribution remained the same. A second explanation of the results is that specific flower species are found in high abundance where their pollinators are found in the highest abundance. As stated pr eviously, floral traits likely are a product of coevolution with their specific pollinators (Murray et al. 2000). It is also thought that various flowering phonologies are adaptations by plants to avoid competition because flowering biology is strongly inf luenced by nectarivores (Young and McDonald 2000). In accordance with these ideas, long or short corolla (tubular) flowers that are primarily orange and red, therefore attracting hummingbirds, should be located in the upper ranges of altitude where humming birds occur with highest frequency. Likewise, flowers that are white, yellow, or blue and are fairly flattened or have a very short corolla with landing platform petals should occur with greatest abundance where their bee and generalist insect pollinators occur most: the lower reaches of the elevational bands chosen for this study. In other words, these results

PAGE 5

support the idea that the stratification that is observed in the major nectarivores of the Monteverde area (hummingbirds, bees, and other insects) w hich places the hummingbirds at the top of an elevational gradient and bees/insects near the bottom due to abiotic habitat factors has corresponding elevationally differing floral color and shape patterns. In addition to further seasonal investigation of this idea, it would be interesting to include canopy flowers to a greater detail as bees are major pollinators of canopy trees. There are also several plant species, e.g. Besleria princeps (Gesneriaceae), wh ich are common in both high and low altitudes and which are of a shape and color that would attract hummingbirds, yet which are so low to the ground (15cm or less above ground) that it is unlikely that hummingbirds visit them. These flowers are presumably vegetatively reproductive and should not then be found on an elevational gradient and it would be interesting to determine whether this expectation is true or not. ACKNOWLEDGMENTS I would like to thank Karen Masters and Andres Vaughan for their assistanc e in formulating ideas and methods for this project, and to Andrew Rodstrom, Matt Gasner, and Carmen Rojas for their patience and help with the millions of questions I had and especially for their help in identifying my flowers. I also would like to thank John Benjamin and Andrew Gapinski for their expert photography skills, motivational pep talks, and endless jokes. Finally, I thank the Estacin Biolgica Monteverde, Monteverde Cloud Forest Preserve, and Bosque Eterno de los Nios for allowing my project t o be done on their land. LITERATURE CITED Bawa, K.S. 1990. Plant Pollinator Interactions in Tropical Rain Forests. Ann. Rev. Ecol. Syst 21:399 422. Haber, W.A. 2000. Plants and Vegetation. Pages 39 69 In Nadkarni, N.M. and N.T. Wheelwright, editors. Mo nteverde: Ecology and Conservation of a Tropical Cloud Forest Oxford University Press, New York, USA. Heywood, V.H., editor. 1993. Flowering Plants of the World. Oxford University Press, New York, USA. Murray, K.G., S. Kinsman, and J.L. Bronstein. 2000. Plant Animal Interactions. Pages 245 256 In Nadkarni, N.M., and N. T. Wheelwright, editors. Monteverde: Ecology and Conservation of a Tropical Cloud Forest Oxford University Press, New York, USA. Raven, P.M., R.F. Evert, and S.E. Eichhorn. 1999. Biology of Plants. W.H. Freeman and Company/Worth publishers, New York, USA. Stiles, F.G., and A.F. Skutch. 1989. A Guide to the Birds of Costa Rica. Comstock Publishing Associates, New York, USA. Young, B.E., and D.B. McDonald. 2000. Birds. Pages 1 99 201 In Nadkarni, N.M. and N.T. Wheelwright, editors. Monteverde: Ecology and Conservation of a Tropical Cloud Forest Oxford University Press, New York, USA.


xml version 1.0 encoding UTF-8 standalone no
record xmlns http:www.loc.govMARC21slim xmlns:xlink http:www.w3.org1999xlink xmlns:xsi http:www.w3.org2001XMLSchema-instance
leader 00000nas 2200000Ka 4500
controlfield tag 008 000000c19749999pautr p s 0 0eng d
datafield ind1 8 ind2 024
subfield code a M39-00446
040
FHM
0 041
eng
049
FHmm
1 100
Fraser, Sarah
242
Marlene
245
Flower Color and Shape Variation on an Elevational Gradient
260
g 2003-12
500
Digitized by MVI
3 520
Many flowering plant species have coevolved with pollinator species to form fairly specialized
pollination systems that involve both color and shape of flowers, for example red and orange tubularshaped
flowers are attractive to hummingbirds and white, yellow, and blue disk and head shaped flowers
are attractive to insects. In Monteverde, Puntarenas, Costa Rica an elevational gradient of pollinator
animals has been observed such that cool temperatures in the high altitude regions limit insect activity to
low elevations, thereby leaving the high elevation pollination to hummingbirds, leading to the hypothesis
that flower color and shape patterns would reflect this pollinator gradient. A patch of continuous forest on
the Pacific slope of the Monteverde area was divided into 50m elevational bands from 1250m to 1400m
and from 1550m to 1750m and flowering plants censused for color and shape along trails in those bands.
Orange and red tubular flower were significantly more abundant in the high elevation bands and blue,
white, and yellow/green disk and aster flowering plants were significantly more abundant at the lower
elevations. These differences in abundance along the elevational gradients reflect the pattern of
hummingbird presence domination at high elevation and insect domination at low elevation.
Una porcin grande de florecer la especie de planta ha coevolucionado con la especie polinizadora en
tanto que ellos habido especializado sistemas de polinizacin en cual o pocos polinizadora, eso est en el
mismo grupo taxonmico (E.G. los colibrs), poliniza una especie de planta. Esta especializacin puede
contribuir a un declive del elevational del color de flor y forma que corresponder con el declive de
elevational en la especie polinizadora que resulta de nicho que divide debido a factores no biticos de
hbitat. En Monteverde, Puntarenas, Costa Rica un declive de elevational de animales polinizadoras se ha
observado tanto que refrescado las temperaturas en las regiones altas de la altitud en la actividad Pacfica
de insecto de lmite de cuesta a elevaciones bajas, con lo cual saliendo la polinizacin alta de la elevacin
a colibrs y lo fue formado una hiptesis ese color de flor y las pautas de la forma reflejaran este declive.
El bosque continuo de la cuesta Pacfica del rea de Monteverde se dividi en 50 bandas de elevational M
de 1250 M -1400M y 1550 M 1750 M y florecer censused de plantas para el color y la forma por rastros
en esas bandas. Tanto el color como la forma se vieron para estar difiriendo apreciablemente de sobra por
el declive de elevational y de tal manera de reflejar como la pauta de la dominacin de la presencia del
colibr en la elevacin alta a la dominacin del insecto en la elevacin baja.
546
Text in English.
650
Flowers
Pollination
Plants--Effect of altitude on
Costa Rica--Puntarenas--Zona de Monteverde--Monteverde
4
Flores
Polinizacin
Marlene
Costa Rica--Puntarenas--Zona de Monteverde--Monteverde
653
Tropical Ecology Fall 2003
Ecologa Tropical Otoo 2003
655
Reports
720
MVI
773
t Monteverde Institute : Tropical Ecology
856
u http://digital.lib.usf.edu/?m39.446