10.5061/DRYAD.771T4
Nielsen, Scott E.
University of Alberta
Larsen, Terrence A.
fRI; Hinton AB Canada
Stenhouse, Gordon B.
University of Alberta
Coogan, Sean C. P.
University of Sydney
University of Alberta
Data from: Complementary food resources of carnivory and frugivory affect
local abundance of an omnivorous carnivore
Dryad
dataset
2016
Ursus arctos
resource co-limitation
nutritional landscape
2016-09-22T16:35:39Z
2016-09-22T16:35:39Z
en
https://doi.org/10.1111/oik.03144
53656 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
A major unresolved question for omnivorous carnivores, like most species
of bears, is to what degree are populations influenced by bottom–up (food
supply) or top–down (human-caused mortality) processes. Most previous work
on bear populations has focused on factors that limit survival (top–down)
assuming little effect of food resource supply. When food resources are
considered, most often they consider only the availability/supply of a
single resource, particularly marine-subsidized or terrestrial sources of
protein (carnivory) or alternately hard or soft mast (frugivory). Little
has been done to compare the importance of each of these factors for
omnivorous bears or test whether complementary resources better explain
individual animal and population measures such as density, vital rates,
and body size. We compared landscape patterns of digestible energy (kcal)
for buffaloberry (a key source of carbohydrate) and ungulate matter (a key
source of protein and lipid) to local measures in grizzly bear Ursus
arctos abundance at DNA hair snag sites in west-central Alberta, Canada.
We tested support for bottom–up hypotheses in either single (carnivory
[meat] versus frugivory [fruit]) or complementary (additive or
multiplicative) food resources, while accounting for a well-known top–down
limiting factor affecting bear survival (road density). We found support
for both top–down and bottom–up factors with complementary resources
(co-limitation) supported over single resource supplies of either meat or
fruit. Our study suggests that the availability of food resources that
provide complementary nutrients is more important in predicting local bear
abundance than single foods or nutrients (e.g. protein) or simply energy
per se. This suggests a nutritionally multidimensional bottom–up
limitation for a low density interior population of grizzly bears.
Measures of local grizzly bear abundance and surrounding road density and
food supplyData fields: 1) "DNA_sampling_cell_ID" is the 7x7 km
cell used to allocate hair snag sites and used as a random effect in
models; 2) "Session_number" is the 2 week session number of
sampled site between 25 May and 17 July 2004; 3)
"Number_grizzlybears" is the unique bears detected at hair snag
site; 4) "Road_density_7440m" is the moving window road density
(km/km^2) within a 7440 m radius window calculated in ArcGIS; 5)
"Shep_can_fruit_DigE_1690m" is the modeled digestible energy
(kcal) of Shepherdia canadensis fruit within a 1690 m radius of the hair
snag site summarized in an ArcGIS moving window; 6)
"Shep_can_fruit_DigE_7440m" is the modeled digestible energy
(kcal) of Shepherdia canadensis fruit within a 7440 m radius of the hair
snag site as summarized in an ArcGIS moving window; 7)
"Ungulate_DigE_7440m" is the digestible energy (kcal) of
ungulate matter within a 7440 m radius of the hair snag site as summarized
in an ArcGIS moving window; 8) "NDVI_JulyMax_1690m" is the
Natural Difference Vegetation Index (NDVI) maximum value in the month of
July from MODIS remote sensing data during the year 2006 with values
averaged within a 1690 m radius of the hair snag site as summarized in an
ArcGIS moving window; 9) "NDVI_JulyMax_7440m" is the Natural
Difference Vegetation Index (NDVI) maximum value in the month of July from
MODIS remote sensing data during the year 2006 with values averaged within
a 7440 m radius of the hair snag site as summarized in an ArcGIS moving
window.Nielsen_et_al_Oikos_data_file.csv
Alberta Canada