Physical and biotic determinants of space utilization by the Galapagos land iguana (Conolophus pallidus)

K.A. Christian, C.R. Tracy

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Home ranges of the Galapagos land iguana (Conolophus pallidus) were examined with respect to food availability and the thermal environment. Activity patterns, the amount of space used per day, and time required to use the entire home range were also investigated. The effects of, and the relationships between, these factors vary seasonally, as do home range sizes and preferred body temperatures. Food supplementation experiments resulted in only temporary reductions in use of space. Home range sizes were not different between the seasons with the least (Fall) and the most (Hot) food availalble, but home ranges were significantly smaller in Garua when food supplies were low, but not as low as in Fall. Calculations of metabolic expenditures in each season suggests that food availability alone does not explain seasonal patterns of home range size in this species. The thermal environment within each home range was characterized by microclimatic measurements and measurements of the area of sun, shade, and semi-shade. An index with units of m2h was used to quantify the thermal quality of each home range. Iguanas exploited optimal (with respect to body temperature) conditions more than would be expected from random use of their home ranges. Thermal transients (due to large body size) and optimal conditions were exploited to the largest degree in Fall. During Garua, low metabolic rates and time constraints imposed by an abundance of stressful thermal environments may result in small home ranges. In Fall, increased temperatures cause higher metabolic rates and allow more time for exploitation of the cooler portions of the home range, hence, home range sizes increase. In the Hot season, there is abundant food and optimal thermal conditions, but home ranges remain large. Searching for preferred foods may cause the large home ranges in this season. © 1985 Springer-Verlag.
Original languageEnglish
Pages (from-to)132-140
Number of pages9
JournalOecologia
Volume66
Issue number1
DOIs
Publication statusPublished - 1985
Externally publishedYes

Fingerprint

home range
heat
range size
body temperature
land
Conolophus subcristatus
Conolophus
food availability
food
shade
food supplementation
Iguana (Iguanidae)
activity pattern
warm season
food supply
coolers
expenditure
body size
seasonal variation

Cite this

@article{6cfdaa845f4743809153b105dd5a11d7,
title = "Physical and biotic determinants of space utilization by the Galapagos land iguana (Conolophus pallidus)",
abstract = "Home ranges of the Galapagos land iguana (Conolophus pallidus) were examined with respect to food availability and the thermal environment. Activity patterns, the amount of space used per day, and time required to use the entire home range were also investigated. The effects of, and the relationships between, these factors vary seasonally, as do home range sizes and preferred body temperatures. Food supplementation experiments resulted in only temporary reductions in use of space. Home range sizes were not different between the seasons with the least (Fall) and the most (Hot) food availalble, but home ranges were significantly smaller in Garua when food supplies were low, but not as low as in Fall. Calculations of metabolic expenditures in each season suggests that food availability alone does not explain seasonal patterns of home range size in this species. The thermal environment within each home range was characterized by microclimatic measurements and measurements of the area of sun, shade, and semi-shade. An index with units of m2h was used to quantify the thermal quality of each home range. Iguanas exploited optimal (with respect to body temperature) conditions more than would be expected from random use of their home ranges. Thermal transients (due to large body size) and optimal conditions were exploited to the largest degree in Fall. During Garua, low metabolic rates and time constraints imposed by an abundance of stressful thermal environments may result in small home ranges. In Fall, increased temperatures cause higher metabolic rates and allow more time for exploitation of the cooler portions of the home range, hence, home range sizes increase. In the Hot season, there is abundant food and optimal thermal conditions, but home ranges remain large. Searching for preferred foods may cause the large home ranges in this season. {\circledC} 1985 Springer-Verlag.",
author = "K.A. Christian and C.R. Tracy",
year = "1985",
doi = "10.1007/BF00378565",
language = "English",
volume = "66",
pages = "132--140",
journal = "Oecologia",
issn = "0029-8549",
publisher = "Springer-Verlag London Ltd.",
number = "1",

}

Physical and biotic determinants of space utilization by the Galapagos land iguana (Conolophus pallidus). / Christian, K.A.; Tracy, C.R.

In: Oecologia, Vol. 66, No. 1, 1985, p. 132-140.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Physical and biotic determinants of space utilization by the Galapagos land iguana (Conolophus pallidus)

AU - Christian, K.A.

AU - Tracy, C.R.

PY - 1985

Y1 - 1985

N2 - Home ranges of the Galapagos land iguana (Conolophus pallidus) were examined with respect to food availability and the thermal environment. Activity patterns, the amount of space used per day, and time required to use the entire home range were also investigated. The effects of, and the relationships between, these factors vary seasonally, as do home range sizes and preferred body temperatures. Food supplementation experiments resulted in only temporary reductions in use of space. Home range sizes were not different between the seasons with the least (Fall) and the most (Hot) food availalble, but home ranges were significantly smaller in Garua when food supplies were low, but not as low as in Fall. Calculations of metabolic expenditures in each season suggests that food availability alone does not explain seasonal patterns of home range size in this species. The thermal environment within each home range was characterized by microclimatic measurements and measurements of the area of sun, shade, and semi-shade. An index with units of m2h was used to quantify the thermal quality of each home range. Iguanas exploited optimal (with respect to body temperature) conditions more than would be expected from random use of their home ranges. Thermal transients (due to large body size) and optimal conditions were exploited to the largest degree in Fall. During Garua, low metabolic rates and time constraints imposed by an abundance of stressful thermal environments may result in small home ranges. In Fall, increased temperatures cause higher metabolic rates and allow more time for exploitation of the cooler portions of the home range, hence, home range sizes increase. In the Hot season, there is abundant food and optimal thermal conditions, but home ranges remain large. Searching for preferred foods may cause the large home ranges in this season. © 1985 Springer-Verlag.

AB - Home ranges of the Galapagos land iguana (Conolophus pallidus) were examined with respect to food availability and the thermal environment. Activity patterns, the amount of space used per day, and time required to use the entire home range were also investigated. The effects of, and the relationships between, these factors vary seasonally, as do home range sizes and preferred body temperatures. Food supplementation experiments resulted in only temporary reductions in use of space. Home range sizes were not different between the seasons with the least (Fall) and the most (Hot) food availalble, but home ranges were significantly smaller in Garua when food supplies were low, but not as low as in Fall. Calculations of metabolic expenditures in each season suggests that food availability alone does not explain seasonal patterns of home range size in this species. The thermal environment within each home range was characterized by microclimatic measurements and measurements of the area of sun, shade, and semi-shade. An index with units of m2h was used to quantify the thermal quality of each home range. Iguanas exploited optimal (with respect to body temperature) conditions more than would be expected from random use of their home ranges. Thermal transients (due to large body size) and optimal conditions were exploited to the largest degree in Fall. During Garua, low metabolic rates and time constraints imposed by an abundance of stressful thermal environments may result in small home ranges. In Fall, increased temperatures cause higher metabolic rates and allow more time for exploitation of the cooler portions of the home range, hence, home range sizes increase. In the Hot season, there is abundant food and optimal thermal conditions, but home ranges remain large. Searching for preferred foods may cause the large home ranges in this season. © 1985 Springer-Verlag.

U2 - 10.1007/BF00378565

DO - 10.1007/BF00378565

M3 - Article

VL - 66

SP - 132

EP - 140

JO - Oecologia

JF - Oecologia

SN - 0029-8549

IS - 1

ER -