The ecology of jaguars (panthera onca) in a human-influenced landscape
The ecology of jaguars (panthera onca) in a human-influenced landscape
Despite intense persecution over the last century, the jaguar (Panthera onca) has sustained a
wide geographic distribution, perhaps due to its elusive nature and rather flexible ecology. This
study investigated jaguar ecology under anthropogenic pressures in Belize, Central America. A
suite of methods including camera-trap surveys, diet analysis, discussions with local
stakeholders, and population simulations were used to study a population of jaguars spanning
the boundary of a protected forest.
Camera-trap data combined with capture-recapture population models are increasingly used to
estimate the density of mammals such as jaguars with individually identifiable coat patterns. A
review of current methods highlighted problems associated with estimating the sizes of lowdensity
populations. Simulations to assess the robustness of the method found that camera
failure can negatively or positively bias the abundance estimate, depending on the particular
nature of capture histories. The most commonly used model estimator in the literature was
nevertheless robust to failures of up to 10% of trap-occasions. Pooling trap-occasions reduced
the effect of camera failure. Sub-sampling data from large-scale surveys indicated a threshold
survey area of ~170 km2, below which estimates of density were inflated and unreliable. For
surveys exceeding this threshold size, jaguar density varied across the landscape from the
protected forest to the human-influenced lands such that <30% contiguous forest precipitated
reduction. Reduced densities with distance from contiguous forest and proximity to human
habitation may result principally from direct conflicts with people.
The influence of anthropogenic factors on the coexistence of jaguars and pumas (Puma
concolor) was investigated by comparing their habitat use and feeding ecology. Diet was
analysed from the largest sample to date of scats from one area identified to species. Jaguars and
pumas made similar use of the secondary rainforest, despite differences in diet. Although both
cats relied heavily on one species of small prey (5-10 kg), for jaguars this was the nine-banded
armadillo (Dasypus novemcinctus) while for pumas it was the paca (Agouti paca). Both cats
took some larger prey, mainly white-lipped peccaries (Dictolyes pecari) by jaguars and red
brocket deer (Mazama americana) by pumas. Energetics models indicated that reproduction
may be limited for either species if large prey are unavailable for females with dependents.
Outside the forest block, jaguars rarely ate large wild prey species; instead, a diet of smaller
wild prey was supplemented with large domestic stock. Pumas were scarce outside the protected
forest, possibly reflecting a reluctance to utilise domestic species near human developments and
competition with humans for their preferred prey of paca and deer, which are also prized
regionally as game species.
Human-induced mortality of jaguars outside the protected forest was mainly associated with
livestock predation. Both sexes were equally active on pastures and were persecuted at a similar
rate. Many of those killed were young individuals in good body condition, suggesting high
turnover rates augmented by immigration. Population simulations indicated that the observed
levels of human-induced mortality could be maintained only with immigration from the
protected forest. Without natal dispersers (2-4 year olds) immigrating in, the hunted population
had zero probability of persisting beyond 20 years. Simulations indicated that the jaguar
populations inhabiting the two main protected forest blocks in Belize could persist in isolation
and maintain low levels of emigration to the unprotected population. However the probability of
all three populations persisting for 100 years fell to ~50% if the migration of natal dispersers
from the protected to unprotected population exceeded ~12% per year.
Foster, Rebecca
928914f2-32cc-495d-82d3-304dc3ee4fb9
December 2008
Foster, Rebecca
928914f2-32cc-495d-82d3-304dc3ee4fb9
Doncaster, C.P.
0eff2f42-fa0a-4e35-b6ac-475ad3482047
Foster, Rebecca
(2008)
The ecology of jaguars (panthera onca) in a human-influenced landscape.
University of Southampton, School of Biological Sciences, Doctoral Thesis, 358pp.
Record type:
Thesis
(Doctoral)
Abstract
Despite intense persecution over the last century, the jaguar (Panthera onca) has sustained a
wide geographic distribution, perhaps due to its elusive nature and rather flexible ecology. This
study investigated jaguar ecology under anthropogenic pressures in Belize, Central America. A
suite of methods including camera-trap surveys, diet analysis, discussions with local
stakeholders, and population simulations were used to study a population of jaguars spanning
the boundary of a protected forest.
Camera-trap data combined with capture-recapture population models are increasingly used to
estimate the density of mammals such as jaguars with individually identifiable coat patterns. A
review of current methods highlighted problems associated with estimating the sizes of lowdensity
populations. Simulations to assess the robustness of the method found that camera
failure can negatively or positively bias the abundance estimate, depending on the particular
nature of capture histories. The most commonly used model estimator in the literature was
nevertheless robust to failures of up to 10% of trap-occasions. Pooling trap-occasions reduced
the effect of camera failure. Sub-sampling data from large-scale surveys indicated a threshold
survey area of ~170 km2, below which estimates of density were inflated and unreliable. For
surveys exceeding this threshold size, jaguar density varied across the landscape from the
protected forest to the human-influenced lands such that <30% contiguous forest precipitated
reduction. Reduced densities with distance from contiguous forest and proximity to human
habitation may result principally from direct conflicts with people.
The influence of anthropogenic factors on the coexistence of jaguars and pumas (Puma
concolor) was investigated by comparing their habitat use and feeding ecology. Diet was
analysed from the largest sample to date of scats from one area identified to species. Jaguars and
pumas made similar use of the secondary rainforest, despite differences in diet. Although both
cats relied heavily on one species of small prey (5-10 kg), for jaguars this was the nine-banded
armadillo (Dasypus novemcinctus) while for pumas it was the paca (Agouti paca). Both cats
took some larger prey, mainly white-lipped peccaries (Dictolyes pecari) by jaguars and red
brocket deer (Mazama americana) by pumas. Energetics models indicated that reproduction
may be limited for either species if large prey are unavailable for females with dependents.
Outside the forest block, jaguars rarely ate large wild prey species; instead, a diet of smaller
wild prey was supplemented with large domestic stock. Pumas were scarce outside the protected
forest, possibly reflecting a reluctance to utilise domestic species near human developments and
competition with humans for their preferred prey of paca and deer, which are also prized
regionally as game species.
Human-induced mortality of jaguars outside the protected forest was mainly associated with
livestock predation. Both sexes were equally active on pastures and were persecuted at a similar
rate. Many of those killed were young individuals in good body condition, suggesting high
turnover rates augmented by immigration. Population simulations indicated that the observed
levels of human-induced mortality could be maintained only with immigration from the
protected forest. Without natal dispersers (2-4 year olds) immigrating in, the hunted population
had zero probability of persisting beyond 20 years. Simulations indicated that the jaguar
populations inhabiting the two main protected forest blocks in Belize could persist in isolation
and maintain low levels of emigration to the unprotected population. However the probability of
all three populations persisting for 100 years fell to ~50% if the migration of natal dispersers
from the protected to unprotected population exceeded ~12% per year.
Text
RFoster_2008_PhD_thesis.pdf
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Published date: December 2008
Organisations:
University of Southampton
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Local EPrints ID: 66711
URI: http://eprints.soton.ac.uk/id/eprint/66711
PURE UUID: 9e43dccb-90db-47e2-8e05-550367a8b128
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Date deposited: 14 Jul 2009
Last modified: 14 Mar 2024 02:38
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Author:
Rebecca Foster
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