From detection to restoration: lessons from butterflies to improve conservation efficiency

3 Pages·2002·0.6 MB·English

by  Van Dyck, H

BULLETIN DE L'INSTITUT ROYAL DES SCIENCES NATURELLES DE BELGIQUE BIOLOGIE, 72-SUPPL.: 179-181,2002
BULLETIN VAN HET KONINKLIJK BELGISCI-IINSTITVUT VOOR NATUURWETENSCI-IAPPEN BIOLOGIE, 72-SUPPL.: 179-181,2002
Frotn detection to restoration:
lessons from butterflies to improve conservation efficiency
H. VANDYCK
Introduction Butterflies are among the few invertebrates that easily
attract public attention, but also quite a lot of scientific
Establishing the conservation status and distribution interest. Aesthetic values should not be mixed with eco
trends of species or taxonomic groups is considered a logical functions and knowledge to derive conservation
valuable task for conservation. Further and increasing surrogates or indicators. Nevertheless, the use of butter
efforts to survey more species or taxonomic groups have flies for conservation purposes has been advocated se-
been advocated before, and will be advocated several . · vera! times before: butterfly species have high demands
times at this Belgian Biodiversity meeting. I do support for habitat quality and they often respond fast to habitat
this view, but measuring or estimating changes in dis changes (THOMAS 1994, WOIWOD & THOMAS 1993).
tribution -in particular using current approaches-is only a However, it should be realised that no single species or
first step in a conservation process. Moreover, there are taxonomic group can be considered a universal bio
several potential problems with analyses based on typical indicator (e.g. SIMBERLOFF 1998). Within this context, we
distribution datasets. Much more detailed ecological recently finalised a study for the Flemish Ministry of
knowledge is required to bridge the gap qetween detec Nature Conservation on the use of multi-species ap
tion and restoration. proaches (VAN DYCK et al. 200 I), which is not further
To do so, critical, scientific approaches are required, discussed here.
but they do not necessarily guarantee any impact on
conservation practice if conclusions do not fit within the
framework of practical conservation management and/or Status and trends of butterflies
policy (PULLIN & KNIGHT 200 l ). So far, a few attractive
species have been used as conservation targets, but the use Our analyses clearly indicate that butterflies have expe
of species as tools for site- or landscape-oriented conser rienced severe losses in Flanders: 19 of the 64 indigenous
vation is yet poorly developed. I will address some issues species went extinct and half of the remaining species are
to implement species-specific knowledge using butterflies threatened to a certain extent. The number of extinct
(Rhopalocera) as an example. species is among the highest throughout Europe. Using
5 X 5 km distribution grid cells (UTM projection), the
number of diversity hot spots decreased considerably
Why butterflies, why Flanders? and present-day hot spots are almost exclusively found
in NE-Flanders (de Kempen). Butterflies have the advan
I refer to results on butterflies in Flanders, the northern tage that several aspects of their ecology have been
region of Belgium. This is because conservation policy studied. Hence, further analyses to get a better under
and practice are mainly a matter of the regions rather than standing of butterfly diversity loss are possible. We, for
of the federal Belgian government. Butterflies are among instance, found that species with low dispersal capacities
the best-studied groups of animals, particularly among and species from oligotrophic habitats decreased signifi
invertebrates (NEW 1997). For Flanders there is an ex cantly more than mobile species and species from eu
tensive distribution dataset (> I 90.000 records), a Red trophic habitats. Such relationships point to effects of
List (MAES & VAN DYCK 1996), a documented distribu destruction and fragmentation of suitable butterfly habi
tion atlas (MAEs & VAN DvcK 1999), and relative abun tats and to the strong impact of intensification of agricul
dance is monitored in a standardised way for about I 0 tme (including high nitrogen input), respectively. An
years (although on a small sample of sites). Note that example of a butterfly that declined severely is Lycaena
there is a general bias in conservation biology towards tityrus (fig. I). For more detailed results and a discussion
attractive species including birds, mammals and vascular on the severe loss of butterfly diversity in Flanders, I refer
plants. to MAES & VAN DYCK (200 I).
I I
180 H. VANDYCK
Problems with distribution data wet, nutrient-poor grasslands (V ANREUSEL et a/. 2000).
Such a plan was requested and funded by the Flemish
Distribution data are of great potential value to conservation. Ministry ofNatme Conservation. So far, there is only little
However, dish·ibution datasets collected over many years experience in species protection programs in this region,
with different people typically cany several biases making and this was the first plan for an inveiiebrate. M. a/con is in
sound analyses not evident. In order to make sound compa Belgium confined to the NE of Flanders. It is considered
risons of fanner and ctuTent butterfly diversity tlu·oughout threatened at the Belgian (or Flemish) level, and vulne
Flanders, we applied strict criteria on recording intensity to rable at the European level (VAN SWAAY & WARREN 1999).
keep a grid cell in the analysis (MAES & VAN DYCK 200 I). Due to the peculiar life histmy of Maculinea butterflies,
Hence, we only used 23 % of all grid cells, but since they their occtuTence and abundance are directly affected by other
were fairly well spread over the different ecoregions of Flan organisms in their habitat. M a/con is a monophagous
ders, this reduced sample was still representative of flanders herbivorous specialist laying eggs on the Marsh gentian
as a whole. Problems on biases in distribution data due to (Gentiana pneumonanthe). YOtmg caterpillars leave their
temporal and spatial differences in recording effmis have hostplant to be adopted by Myrmica ants. Hence, this butter
been analysed and discussed in much detail for British butter fly has an obligate, ant-parasitic life stage adopting a cuckoo
fly data (e.g. DENNIS eta/. 1999, DENNIS & THOMAS 2000). sh·ategy. Adoption of the caterpillars is mediated by complex
Another issue that has often been denied is the effect of chemical ant brood mimic1y. The larval stage lasts either one
grid resolution on detecting trends. In Belgium (like else or two years. Next, they pupate in the ant nest and emerge as
where), units of distribution are often coarse-grained grid adults in the summer. In om region, Mynnica ruginodis
cells like 5 x 5 km or even I 0 x I 0 km square grids of the is recognised to be the optimal host ant, but other Nfyrmica
UTM-projection. Using such grid cells as surrogates in ants also occm in wet heathlands. We collected detailed data
stead of real distribution -which is a large amount of work on butterflies (MRR-data on adults, egg cotmts), hostplants
to define- implies that the distribution of several species .. (abundance, age distribution), host ants (density of colonies),
is overestimated and their decline underestimated. This vegetation shl.Ictme and management in all but one popula
particularly matters for species that are still widely oc tions that cunently remain.
curring, but which are (strongly) declining (e.g. COWLEY Many specialist species -including M. alcon- have dis
et al. 1999). These issues are clearly not typical for appeared also from nature reserves when specific know
butterfly data, and should be taken into account for any ledge was not available to be taken into account for con
analysis using similar data resources. The importance of servation practices. Management is mainly based on h·adi
standardised methods to collect data should be realised tion and intuition rather than on evidence (see PULLIN &
when new (volunteer) survey projects are initiated. KNIGHT 200 I). For this project we particularly endea
voured to make a scientific-based plan that has a ve1y
practice-oriented output as well. Hence, one paii of the
report brought together all analysed data and discussed
Detailed ecological knowledge and practical conserva
knowledge on the ecology and conservation of the species,
tion: the Alcon blue case
its hostplant, host ants and complex relationships with its
habitat. The other volume of the report sunm1arised pro
We have recently finalised a recovery plan for the butterfly
posed measures per site indicating what should be done
Maculinea a/con, a habitat specialist of wet heathlands and
where and how (e.g. quantification of small scale sodcut
ting to restore small gentian populations). This approach
14 was appreciated ve1y much by reserve managers that
require scientific output in· a practice-oriented way and
12
not only in an academic format. On the other hand, the
extensive dataset also allowed to address more ecological
~ 10
questions like the controversial role of the host ants for
.!!!.
~ 8 - oviposition decisions (VAN DYCK et al. 2000). We could,
"0 for instance, also illustrate that degree of experience has a
·~
·aal. 6 - strong impact on the quality of apparently simple data like
::J M. a/con egg counts (fig. 2).
g(.) ·4
2
Butterflies as tools fm site- or landscape-oriented
conservation: the challenge of ecological networks
0
1901-1950 1951-1970 1971-1990. 1991-2000 2001
Time period Ecological networks and corridors are hot topics in con
Fig. I Severe decline in distribution of the butterfly Lycaena servation. Connecting areas is ve1y easy to do on a map.
tityrus in Flanders (expressed as percentage of occupied However, biological realism is often lacking when no role
5x5 km UTM grid cells) dLu·ing the 20'11 centmy. Dis organisms are considered. There is a huge bias in our
tribution in the first periods is probably underestimated. knowledge towards woodland systems. ft remains, how-
I'
From detection to restoration: lessons from butterflies to improve conservation efficiency 181
2000 status and decline. Proceedings of the Royal Society ofL ondon
1800 ~- I (B), 266: 1587-1592.
Host plants
1600 c=:J Eggs DENNIS, R.L.H., SPARKS, T.H., & 1-IARDY, P.B., 1999. Bias in
butterfly distribution maps: the effects of sampling effort.
1400
... Journal ofI nsect Conservation, 3: 33-42 .
1200
.Qc) DENNIS, R.L.H. & THOMAS, C.D., 2000. Bias in butterfly dis
E 1000
tribution maps: the influence of hot spots and recorder's home
:::s
z 800 - range. Journal of Insect Conservation, 4: 73-77.
600 MAES, D. & VAN DYCK, H., 1996. Gedocumenteerde Rode Lijst
van de dagvlinders van Vlaanderen. lnstituut voor Natuurbe
400
houd, Brussel.
200 •
MAES, D. & VAN DYCK, H., 1999. Dagvlinders in Vlaanderen:
0
ecologie, verspreiding en behoud. Stichting Leefmilieu m.m.v.
LOW (08-08-01) HIGH (17- 08-01)
Instituut voor Natuurbehoud & Vlaamse Vlindetwerkgroep
Experience
vzw, Antwerpen/Brussel.
Fig. 2 - Effect of experience on the number of observed MAES, D. & VAN DYCK, H., 200 I. Butterfly diversity loss in
hostplants and counted eggs of M. a/con in the same Flanders (north Belgium): Europe's worst case scenario? Bio
population by a team with low and high experience, logical Conservation, 99: 263-276.
respectively. Time between the counts will explain
NEW, T.R., 1997. Are Lepidoptera an effective "umbrella
some of the difference, but the major difference is
group" for biodiversity conservation? Journal of Insect Con
attributed to missed host plants and hence eggs by
servation, 1: 5-12.
the team with low experience.
PULLfN, A.S. & KNIGHT, T.M., 2001. Effectiveness in conserva
tion practice: pointers from medicine and public health. Con
servation Biology, 15: 50-54.
ever to be shown for most non-woodland species (e.g.
SIMBERLOFF, D., 1998. Flagships, umbrellas, and keystones: is
spec,ies of heath lands or marshes) to what extent a hedge
single-species management passe in the landscape era? Biolo
row really provides a corridor for movements through
gical Conservation, 83: 247-257.
non-habitat. Spatially explicit models using GIS provide
THOMAS, J.A., 1994. Why small cold-blooded insects pose
interesting tools to take into account several landscape
different conservation problems to birds in modern landscapes.
features (like the configuration of landscape compo
Ibis, 16: 278-284.
nents). It is, however, necessary to incoi-porate spe~i~s­
VAN DYCK, H., MAES, D. & BRICHAU, I., 200 I. Toepassen van
specific behavioural knowledge into these connectivity
een multi-soortenbenadering bij planning en evaluatie in het
models to increase biological realism.
Vlaamse natuurbehoud. Rapport Onderzoeksgroep Diereneco
So far there is few information on how animals per
logie, Universiteit Antwerpen in opdracht van het Ministerie
ceive (and react on) non-habitat elements when traversing
van de Vlaamse Gemeenschap, afdeling Natuur: 90 pp.
through a landscape (e.g. role of attractants like vegeta
VANDYCK, I-!., 00STERMEIJER, J.G.B., TALLOEN, W., FEENSTRA,
tion borders, resistance of different vegetation types). A
V., VANDER I-IIDDE, A. & WYNHOFF, I., 2000. Does the presence
careful quantification and critical validation of the used
of ant nests matter for ovipo.sition to a specialized myrmeco
parameters is required. One of our other, more recent,
philous Macu/inea butterfly? Proceedings of the Royal Society
lines of research addresses in particular these issues using ofLondon (B), 267: 861-866.
again butterflies (but also other animals) as model organ
VAN SWAAY, C.A.M. & WARREN, M.S., 1999. Red data book of
isms. This work of our group (Laboratory of Animal
European butterflies (Rhopalocera). Nature and environment
Ecology - headed by E. MAT THYSEN) is partly done in
No. 99, Council of Europe Publishing, Strasbourg.
collaboration with UCL (M. BAGUETTE, E. BOULENGE).
VANREUSEL, W., MAES, D. & VAN DYCK, H., 2000. Soort
beschermingsplan GentiaanblaLiwtje. Rapport Onderzoeks
groep Dierenecologie, Universiteit Antwerpen in opdracht
Acknowledgements
van het Ministerie van de Vlaamse Gemeenschap, afdeling
Natuur: 140 pp. + 177 pp.
Much of the work presented, or referred to, during this contribution was
done in co-operation with Dirk MAES (Institute for Nature Conserva WOIWOD, I.P. & THOMAS, J.A., 1993. The ecology of butterflies
tion). I also thank the many volunteers who contributed to the extensive and moths at the landscape level. ln: HAINES-YOUNG, R. (ed.),
distribution dataset of the Flemish Butterfly Working Group (Yiaamse
Landscape ecology in Britain. Department of Geography, Uni
Vlinderwerkgroep vzw). H. VAN DvcK is postdoctoral fellow of the
Fund of Scientific Research Flanders-Belgium (FWO). versity ofNottingham, TALE (UK): 76-92.
Hans VAN DYCK
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