Herpetology Notes, volume 2: 1-7 (2009)
Differences in habitat use, daily activity patterns and preferred
ambient temperatures of adult and neonate Gloydius halys halys
from an isolated population in southwest Siberia: preliminary data
Evgeniy Simonov
Abstract. Differences in habitat selection, daily activity and preferred ambient temperatures between adult and neonate Halys
pit-vipers, Gloydius halys halys (Pallas, 1776) were studied in an isolated population in Novosibirsk region (Russia, southwest
Siberia). Investigations were conducted at the end of August, due to the high abundance of neonates. Simple correspondence
analysis showed that adults and neonates have different habitats and daily activity, and prefer different sun expositions. Multiple
correspondence analysis showed that adult pit-vipers select rocky habitats, southwest exposition and are most active at midday.
Neonates prefer stony steppes, southeast sun exposition and have activity peaks in the morning and evening. Adult snakes select
significant higher ambient temperatures than neonates. Different thermal reactions and different diets may be likely the factors
driving to the differences in habitat use between neonate and adult of G. h. halys.
Key words. Ecology, Gloydius halys halys, Habitat selection, Ontogenetic shifts, Southwest Siberia.
Introduction
Our knowledge of species ecology is the scientific
background for the conservation and management of
threatened species (e.g. Brito 2003, Bjorgan 2005,
Richardson et al. 2006). However, individuals of
marginal and isolated populations of reptiles may
have different ecological features than the conspecific
individuals from other “mainland” populations (e.g.:
Strijbosch et al. 1980, Amat et al. 2003, Tabachishin et
al. 2006), therefore, it is sometimes difficult to extend
our knowledge to all populations of a certain species.
On the other hand, individuals may have different
ecological preferences and have dissimilar activity
depending on the age (e.g. Sun et al. 2001, Amat et al.
2003, Brito 2003). This is especially true for the selection
of preferable habitats (e.g. Lind 1990, Shine et al. 2002,
Bjorgan 2005, Nemes et al. 2006). Ontogenetic shifts in
habitat selection may reflect various age groups’ features
such as predation risk (Keren-Rotem et al. 2006, Werner
et al. 1983), thermal reaction habits (Cherlin 1989,
Winne and Keck 2005, Blouin-Demers et al. 2007),
diet (Lind 1990, Luiselli et al. 1995, Weatherhead et
al. 2003), or lokomotion (Lind 1990, Shine et al. 2002,
Blouin-Demers et al. 2007).
Department of Zoology, Institute of Natural and
Social-Economical Sciences,
Novosibirsk State Pedagogical University,
Viluyskaya street 28, 630126 Novosibirsk, Russia;
e-mail: [email protected]
In southwestern Siberia, the Halys pit viper (Gloydius
halys halys (Pallas 1776) inhabits mountains and
foothills of the Altai-Sayan mountain system (Orlov
and Barabanov 2000, Ananieva et al. 2004, Kuzmin
and Semenov 2006, Simonov 2008). So far, the most
isolated population of G. h. halys is known from the
west Siberia, in the Novosibirsk region (Pestov 2003,
Simonov 2007, 2008). This locality represents the
northwesternmost record of G. h. halys distribution.
The nearest neighbouring populations are at 190-250
km (Simonov 2008).
Due to the natural habitat fragmentation, G. h. halys
shows a patchy distribution, with a series of local
micropopulations along the Berd’ river, where rocky
habitats are available.
Since 2008, this population of Halys pit viper is included
in the Red data book of Novosibirsk region (in press),
and the development of a conservation program based
on the species ecology is a major goal to improve its
protection. Habitat requirements of neonate snakes are
poorly known, even for well-studied species (e.g. BlouinDemers et al. 2007) because of their secretive style of
life. Due to their high abundance (up to 267 individuals
per hectare), Simonov (2007, 2008) considered G.
h. halys to be a good model organism to study snake
ecology. The aim of this paper is to evaluate and analyse
the differences between adult and neonate G. h. halys in
the habitat use preferences, in the daily activity patterns
and in the preferred ambient temperatures.
2
Materials and Methods
Study area
The area of investigation is located in the southeastern part of
Novosibirsk region, on the territory of Maslyanino district (Russia). The study site is a 100m wide strip along the right bank of
the river Berd (54º30´N, 84º03´E), on an elevation between 160
to 219 m a.s.l. At this place, the bedrock foundation are made of
numerous rocks, blocks and stony slide-rocks (Fig. 1c). Berd is
a permanent lowland river (with the exception of the upper end)
25-30m wide (at the study place), showing spring flood. Average
air temperature ranges from -19,1ºC in January to 17,7ºC in July,
annual average air temperature is -0,3ºC, (Kravcov and Donukalova 1996). The average rainfall is 471 mm/year, and the average
monthly rainfall ranges from 14 mm in February to 75 mm in
July, while the precipitation-evaporation ratio is 1,3 (Kravcov
and Donukalova 1996). Due to the agriculture, the valley of the
river is very disturbed, and the native vegetation is preserved only
along the river. The study area is a wood-meadow area, where
birches (Betula sp.) and aspens (Populus sp.) dominate; small
number of Pinus sylvestris and Larix sp. also occur. On the cliffs
are often steppe and petrophyte plants associations.
Field methods
Observations were conducted from 23rd to 30th August 2008. This
time was chosen due to the following reasons: (1) previously
Simonov
observations (Simonov 2007, 2008) showed that neonate (and
juveniles) snakes occur extremely rare during the May–August
period, (2) in this population, females of G. h. halys give birth at
the end of August (3) September weather conditions are often non
optimal for snake observations, and therefore unusable for data
collection. During this short period 25 adult (SVL > 420 mm) and
15 neonate snakes (SVL < 170 mm) were observed.
Surveys of G. h. halys were conducted repeatedly, eight times
during the day (between 08.00-21.00) on transects with non-limited width in the following types of the habitat: (1) “rocky area”,
represented by stony slide-rocks, bulks of large stones and other
rocky areas with similar microclimatic and vegetable conditions
(projective cover of plants less than 25%; basic plant species are
Artemisia frigida Wild., Rubus caesius L., Galium ruthenicum
Willd., Chelidonium majus L., Allium nutans L.) (Fig. 1b); (2)
“stony steppe”, areas where arid soil contains numerous stones,
average projective cover 50-60%, basic plant species are Stipa sp.,
Orostachys spinosa (L.) C. A. Meyer, Spiraea hypericifolia L.,
Caragana frutex (L.) C. Koch, Artemisia frigida Wild., Artemisia
sp. (Fig. 1a); (3) “bottomland”, flood-plain of Berd’ river, where
projective cover of miscellaneous herbs is close to 100%. Single
trees as birches (Betula pendula Roth), aspens (Populus tremula
L.) and willows (Salix rosmarinifolia L.) occour. In contrast to
previous habitats, it is a flat area.
Estimation of snakes’ activity via visual counts was used, although
this method has obvious lacks, being influenced by weather con-
Figure 1. Main habitats of G. h. halys in Novosibirsk region: A – portion of stony steppe; B – portion of stony slide-rocks (the
one variant of “rocky area”); C – view on study site from far bank (stony steppes mainly on a right side of hill, rocky areas
mainly on a left side).
Habitat differences in adult and neonate of G. h. halys
3
ditions, by the snake size, and by the plant coverage (Sun et al.
2001). The following variables were recorded for each individual: time of the day (morning - 09 to 11 a.m., midday – 11 a.m. to
04 p.m., afternoon – 04 p.m. to 08 p.m.), habitat type (rocky area,
stony steppe, bottomland; see above for explanation), exposition (southwest (SW), southeast (SE) or flat area), air temperature
(Ta), air temperature at 5 cm from ground (Ta2), temperature of
substrate (Ts). Temperatures of air and substrate were measured
using a digital thermometer (accuracy 0.1ºC).
vestigate the differences between groups, for Ta and Ts the T-test
was applied, while the nonparametric Mann-Whitney U Test was
applied for Ta2. The statistical processing of data was conducted
with Statistica 6.0.
Statistical procedures
Simple and multiple correspondence analysis (Greenacre 1984)
was used to analyse associations between groups (adults and
neonates) and selected variables (habitat, exposition and daily
activity). All temperature variables (Ta, Ta2, Ts) did not deviate
from normality in both groups (Kolmogorov-Smirnov test for
normality: p > 0.2), but homogeneity of variances between different groups was significant only for Ta and Ts (Levene’s test: p >
0.1), Ta2 was not significant (Levene’s test: p < 0.01). Thus, to in-
Table 1. Summary of simple correspondence analysis.
Ȥ2
df
P
Age * Habitat
28.25
2
< 0.001
Age * Exposition
18.06
2
< 0.001
Age * Part of the day
7.53
2
< 0.05
Table 2. Observed frequencies of character states analysed in
multiple correspondence analyses.
Adults
Neonates
Habitat type
Stony steppe
Rocky area
Bottomland
1
21
3
13
2
0
Exposition
South-east
South-west
Flat area
6
16
3
14
1
0
Part of the day
Morning
Midday
Afternoon
0
13
12
4
5
6
Figure 2. Associations of adult and neonate of G. h. halys in the space as described by the first two correspondent axes of multiple
correspondence analysis.
4
Simonov
Results
were concentrated mainly on adults and did not take
in consideration neonate ecological features. The same
differences in the habitat use between adult and neonate
of Halys pit vipers were recorded from the Zeya sanctuary
(the northeasternmost point of G. halys distributional
range) (N.N. Kolobaev, unpublished data), where
neonates and juveniles prefer more shaded and humid
habitats. In previous studies (Simonov 2007, 2008) it
has been shown that adult individuals of the G. h. halys
population in Novosibirsk region display ecological
differences from populations of the “mainland” area.
Main differencies are the following: they are stenotopic
and have an higher density, which determines the specific
population structure; they are more active during the
day, whereas G. halys from the central part of its range
are more active in the dusk and at night (in summer).
Differences of preferable ambient temperatures may
determine the habitat split among neonate and adult
pit-vipers. As ectotherms, reptiles manipulate habitat
choice and time of activity in an attempt to achieve
body temperatures in preferred ranges (Heath 1965,
Huey, Pianka and Hoffman 1977, Meek and Jayes 1982,
Christian et al. 1983, Litvinov 2008), whereas body
size (and accordingly age) influences thermoregulatory
requirements of ectothermic animals because smaller
individuals warm and cool more quickly than larger
ones (Schmidt-Nielsen 1979, Stevenson 1985). In fact,
differences of preferable habitat and body temperatures
among age groups are common in reptiles, and young
individuals usually choose lesser temperatures than
adults (e.g. Carretero, Marcos and de Prado 2006,
Hitchcock and McBrayer 2006, Xu and Ji 2006). In this
context, detected significant differences of preferable
environmental temperatures can explain shifts in
habitat selection and activity time of adult and neonate
Results of simple correspondence analyses (Table
1) show significant associations between age and
habitat type, exposition, and daily activity. Multiple
correspondence analysis shows very close associations
of neonates and adult snakes with habitat and exposition,
while associations for the time of the day are not so
strong, but also relevant (Fig. 2, Table 2).
Thus, in this season, neonates preferred stony steppes,
slopes of southeast sun exposition and were active during
the whole day. In contrast, adult snakes preferred rocky
areas, southwest sun exposition and were active mostly
at midday and during the afternoon. In the bottomland,
only adult pit-vipers were recorded. Figure 3 displays
differences in daily activity among selected age groups
in two-hour intervals. Neonates of G. h. halys had two
peaks of activity at 09.00-11.00 and 19.00-21.00. Adult
snakes exhibit in front of their hidings after 11.00. Their
activity reaches a plateau between 13.00-19.00. Around
21.00 adult of G. h. halys return to their night shelters.
Changes of environmental temperatures during
observations are presented in Fig. 4. During snake
activity Ta ranges from 16.5 to 28.5ºC, Ta2 from 16.6 to
27.8 ºC and Ts from 14.0 to 25.0 ºC. During observation
period, adult snakes significantly prefered higher Ta, Ta2
and Ts than neonates (see Tab. 3).
Discussion
Results of this study clearly show ontogenetic differences
in all examined variables. Habitat preferences and daily
activity of G. h. halys have been studied in different
populations and several subspecies (Chernov 1954,
Lesnyak 1964, Yakovleva 1964, Ataev 1985, Yakovlev
1985, Borkin et al. 1990, Prokopov et al. 2000, Orlov
et al. 2001, Kolobaev 2006), but these investigations
Table 3. Descriptive statistics of ambient temperatures for adult and neonate of G. halys and their comparison. Descriptive statistics are given as mean ± SE (top), range (middle) and sample size n (bottom). Abbreviations of variables: Ta, air temperature; Ta2,
air temperature on distance of 5 cm from ground; Ts, temperature of substrate.
Variable
Ta
Ta2
Ts
Adults
22.9 ± 0.7
16.5-28.5
24
23.1 ± 1.1
17.0-27.8
21
22.7 ± 0.8
18.9-30.0
21
Neonates
20.5 ± 0.8
16.5-26.5
15
18.3 ± 0.9
16.6-22.6
15
19.5 ± 1.4
14.0-25.0
11
T-test
Mann-Whitney U
p-value
2.17
-
< 0.05
-
2.33
< 0.05
2.11
-
< 0.05
Habitat differences in adult and neonate of G. h. halys
5
active microhabitats to maintain optimal temperatures.
Ambient temperatures affect activity patterns in many
snake species (Gannon and Secoy 1985, Luiselli and
Akani 2002, Litvinov 2008) and differences on preferred
temperatures may determinate dissimilar activity.
Diet properties also seem to be very important factors for
shifts in habitat selection. Studies in different parts of G.
h. halys area show that juveniles prefer to feed on insects
(especially Orthoptera) and small lizards, whereas adult
pit vipers prefer small mammals, rarely lizards (Chernov
1954, Lesnyak 1964, Yakovleva 1964, Yakovlev 1985,
Orlov et al. 2001). According to Lesnyak (1964), in
southeast Kazakhstan the diet of G. halys (with SLV
Figure 3. Activity of adult and neonate of G. h. halys recorded up to 400 mm) consist to 60.6% of invertebrates. Such
during the surveys (summary of 23rd to 30th August 2008).
ontogenetic shifts in diet composition are well known
for snakes (e.g. Saint-Girons 1980, Luiselli et al. 1995,
Brito 2004), because they are gape-limited predators
pit-vipers. Due to the higher vegetation coverage, in (Mushinsky 1987). During observations, numerous
the stony steppe, individuals have more possibilities neonate lizards (Lacerta agilis L., 1758) were recorded
to move faster from shade to sun. Moreover, in this in the stony steppe, whereas in the rocky area and
type of habitat, environment temperatures are more bottomland only few L. agilis and Zootoca vivipara
heterogeneous than in the rocky areas and bottomland. Van Jacquin, 1787 were observed. It is well known that
Neonates activity starts earlier and stops later, more allocation and abundance of insects are mainly dependent
likely because they prefer lower ambient temperatures on plant diversity and coverage (e.g. Yakhontov 1969,
than adults. They are active during the day and choose Speight et al. 1999). Thus, the stony steppe habitat may
Figure 4. Changes of habitat temperatures during the observation period (23rd to 30th August 2008). Middle points represent
mean values and whiskers ± 0.95*SE. Abbreviations of variables: Ta, air temperature; Ta2, air temperature on distance of 5 cm
from ground; Ts, temperature of substrate.
6
provide the highest prey density for neonate pit-vipers.
Differences in diet preference may also lead to shifts
in the habitat use of neonate and juvenile snakes of
various species (e.g. Lind 1990, Weatherhead et al.
2003). Additional data on the ecology of neonate,
juvenile as well as for subadult of G. h. halys are
needed to confirm these observations, and data on
feeding and prey availability in different types of
habitat are particularly needed, because they will help
understanding habitat preferences of pit-vipers and
will allow to infer prognosis on habitat suitability (of
interest for conservation actions). Furthermore, data
on preferred body temperatures are needed to provide
the correct explanation of shifts in habitat selection,
and represent some of the purposes for future research.
Summarizing, this study indicates differences in
habitat selection, daily activity and preferred ambient
temperatures between neonate and adult Halys
pit vipers in the examined population. Thermal
requirements, diet and other biotic factors (such
as predation risk) may be the most likely causes
of ontogenetic changes in habitat selection. My
preliminary results indicate that the stony steppe must
be considered as the critical habitat for the reproduction
of G. h. halys population in Novosibirsk region.
Acknowledgements
I thank V.K. Zinchenko (Institute of Animal Systematic and
Ecology, Russia) for his help with fieldwork and N.N. Kolobaev
(Norskiy reserve, Russia) who provided his unpublished data
about ecology of G. h. halys in the Zeya sanctuary. Also, I thank
anonymous reviewers for useful comments.
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