180
Reserve Selection Problems
ForreserveselectionwedefinetheSDofasubsetofareasastheSDoftheunion
setoftaxapresentintheseareas.Thereserveselectionisformalizedas:
To illustrate the problem consider the geographical distribution of the ten pheas-
ants (Table 1 ). The data were obtained from the global biodiversity information
facility (www.gbif.org; accessed on December 1st, 2013), where a country is listed
as habitat only if there are at least three observations for the species. Table 1 shows
that these pheasants occur in eight countries in South Asia. G. gallus and P. bical-
caratum occur in seven and two countries, respectively, whereas the remaining
speciesareendemictoonecountry.IndonesiaandMalaysiaeachhostthreespecies,
SriLankaonlyonespecies,andtheremainingfivecountriesarehometotwo
species each.
Ifonewantstoselectfourcountrieswithmaximaldiversity,thenthedecision
heavilydependsonthetreesornetwork(Figs. 1 and 2b). Table 2 shows that using
Problem 4 (Reserve Selection)
Given a split set for ntaxadistributedinm areas, find a subset of k areas that
maximizesSDoverallsubsetsofk areas.
P.malacense
P.emphanum
P.bicalcaratum
P.inopinatum
P.chalcurum P.germaini
G.sonneratii
G.gallus
G.lafayetii
G.varius
Fig. 4 Artificialexampleofdependencynetworkforthepheasantdataset
O. Chernomor et al.