Conservation Biology of Lycaenidae (Butterflies) - IUCN
Conservation Biology of Lycaenidae (Butterflies) - IUCN
Conservation Biology of Lycaenidae (Butterflies) - IUCN
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habitats which supported Lycaena dispar, only one or two<br />
species could be found in the more heavily sprayed fields and<br />
here L, dispar was totally absent. Other unpublished observations<br />
give further evidence <strong>of</strong> this effect. The conclusion is that<br />
chemicals can reduce butterfly diversity and that they may be<br />
implicated in the disappearance <strong>of</strong> L. dispar from vast areas in<br />
the region.<br />
Erhardt (1985) showed a negative effect <strong>of</strong> grassland<br />
fertilization: whereas six lycaenids among 30 Lepidoptera were<br />
more abundant in an unfertilized meadow than in unfertilized<br />
areas only one lycaenid out <strong>of</strong> two Lepidoptera was more<br />
abundant in fertilized meadows. Butterfly diversity was also<br />
drastically reduced in fertilized compared with unfertilized<br />
meadows. Balletto et al. (1988), however, failed to demonstrate<br />
the same effect on six fertilized and three unfertilized plots in<br />
the Dolomites.<br />
Climatic change<br />
Any relationship between climate and butterfly fluctuations is<br />
also hard to establish. In the study <strong>of</strong> this process, authors have<br />
referred to short-term climatic fluctuations, which are the only<br />
ones we can analyse. Even this needs a database maintained<br />
over several years, and only the British Butterfly Monitoring<br />
Scheme (BMS) is now available for such studies. Pollard<br />
(1988) stated that some climatic parameters such as summer<br />
temperatures are correlated with high butterfly numbers. Climate<br />
can also represent an important factor when fluctuations in<br />
numbers occur in populations previously isolated by other<br />
means such as habitat destruction. The synergetic effect <strong>of</strong> both<br />
factors can certainly endanger populations that are already<br />
declining. For example, a coincidence <strong>of</strong> habitat damage and<br />
unfavourable weather accelerated the extinction <strong>of</strong> Maculinea<br />
arion in Great Britain (Thomas 1989). Long-term climatic<br />
changes normally represent a natural process, but it is now<br />
uncertain if the short-term fluctuations derived from the<br />
greenhouse effect will have any influence on butterfly<br />
populations. This certainly adds another factor probably having<br />
some effect on butterfly abundance or survival, particularly<br />
when considering rare species.<br />
Tourism and urbanisation<br />
Ever-expanding tourist facilities and advancing urbanisation<br />
are obviously among the factors that threaten many butterfly<br />
populations. Nevertheless their effects are far more restricted<br />
geographically than habitat destruction or alteration due to<br />
changes in land management practices. Tourism is particularly<br />
aggressive in some areas, such as the Mediterranean coast, the<br />
Alps or some parts <strong>of</strong> the Pyrenees, where huge areas have<br />
literally been covered by urbanisation or ski courses.<br />
There is no particular lycaenid restricted to coastal areas<br />
around the Mediterranean, but the effect <strong>of</strong> tourism clearly<br />
makes the species' habitats smaller, acting together with other<br />
more extensive impacts. In northwestern Italy Glaucopsyche<br />
melanops (Boisduval) and Satyrium esculi (Hübner) are<br />
29<br />
threatened by tourist resorts which are now spreading inland<br />
from the sea borders (already totally covered in tarmac and<br />
concrete). Some previously abundant populations <strong>of</strong> Lycaena<br />
thesarmon (Esper) have become extinct as a consequence <strong>of</strong> the<br />
spreading urbanisation around Rome.<br />
High mountain habitats are particularly susceptible to the<br />
impact <strong>of</strong> expanding tourist facilities because they host scarce<br />
and ecologically specialised forms. One example is represented<br />
by Vacciniina optilete in the Alps, which is declining in many<br />
parts <strong>of</strong> its former range (Balletto in press). Another example is<br />
represented by Agriades zullichi and Polyommatus golgus,<br />
very rare endemic lycaenids in Sierra Nevada (southern Spain).<br />
Their range is already restricted by a road and a ski resort<br />
development, but they may now disappear from one <strong>of</strong> their<br />
localities if the planned redevelopments really take place.<br />
Collecting and commerce<br />
Again, every review on the causes <strong>of</strong> butterfly decline and<br />
extinction deals with this topic, but appropriate studies on the<br />
effects <strong>of</strong> collectors on butterfly populations remain wanting.<br />
The appeal <strong>of</strong> this topic probably has something to do with<br />
ethics and with the fact that treating some sophisticated and<br />
non-renewable products <strong>of</strong> nature as items <strong>of</strong> commerce is now<br />
unacceptable; neither does it seem correct to kill animals that<br />
other agencies are striving to conserve. Some collecting is still<br />
necessary in areas where our faunistic knowledge is poor.<br />
Sometimes forbidding collection does little if any good for<br />
butterflies (Kudrna 1986). Results obtained from the<br />
enforcement <strong>of</strong> bans on butterfly collection in some cases have<br />
shown this to be an unsuccessful management practice: in<br />
Germany a ban on the collection <strong>of</strong> four butterfly species passed<br />
in 1936 has not prevented the dramatic decline <strong>of</strong> these species<br />
in the course <strong>of</strong> the last 55 years (Kudrna 1989).<br />
In large populations the number <strong>of</strong> butterflies a collector can<br />
take is really negligible, not reaching 10% <strong>of</strong> the total daily<br />
population estimates, while small populations are normally <strong>of</strong><br />
little interest to commercial collectors. To destroy one <strong>of</strong> these<br />
small populations by collection it is necessary to kill almost all<br />
the butterflies seen during the flight period: this represents a<br />
highly time-consuming job with slight rewards for the collector<br />
(Munguira et al. in press).<br />
Legislation to protect species and habitats<br />
In the last 30 years some European countries have passed laws<br />
protecting butterfly species. Heath (1981) reviewed this topic<br />
gathering data from 25 European countries, 13 (52%) <strong>of</strong> which<br />
had some legislation on the matter while only three countries<br />
(12%) included lycaenids among the protected species. In this<br />
review protected lycaenids were Maculinea alcon, M. alcon, M.<br />
teleius, Lycaena dispar, L. helle and Polyommatus bellargus.<br />
Most <strong>of</strong> this legislation has been ineffective because it was based<br />
on the species themselves and paid little attention to habitats.