37 Chitty, D. 1938. A laboratory study of pellet ... 38 Chitty, D. 1996. Do lemmings commit suicide? .... Koffijberg, K., Mahéo, R.,. Rowcliffe, M., St Joseph, A.K.M.,.
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PETER ESSELINK
Do greylags dig their own graves? Habitat degradation in natural systems Grazers and their food plants are not always in equilibrium. Time of year, the parts of the plant used, and the intensity and timing of use all influence the status of the interaction. Grazers that excavate underground plant parts by ‘grubbing’ often have more long-term impacts on plants than those that only remove surface material (the more common feeding mode). Some goose species such as the greylag are real diggers, and increasing goose numbers appear largely responsible for the near disappearance of Scirpus along the marsh fringes of the Eems estuary in the Dollard.
gists has been studying both the geese and the vegetation for several decades. The enormous concentrations of snow geese grubbing to extract underground roots in spring, have caused a form of desertification extending over tens of square kilometres. The bare patches left behind by the grubbing geese wash out during the spring thaw, often reverting to bare gravel. This system is no longer in balance, and management now aims to reduce the goose populations. Closer to home we may be witnessing a similar train of events. In the 1960s the Scirpus beds in the Krammer-Volkerak, which was then still brackish and tidal, disappeared after severe grazing by greylag geese. These beds never recovered, probably because once the Scirpus and its extensive root system had been removed the soil was vulnerable to waves and currents. Erosion did the rest. The greylags had undermined the system they depended on.
Some geese are equipped for digging and once they’ve started excavating they will continue until all edible parts of the plant have been extracted. Often they start by wrenching off the aboveground parts and removing these completely. A year later the impact on plant productivity is still visible. Measurements on Spartina and Scirpus vegetation in salt marshes in eastern North America revealed that patches excavated by snow geese during winter and on migration took more than a year to recover. But that’s not all. Sometimes the digging by the geese has such negative effects on the physical environment that the plants’ recovery takes much longer, or in some cases never occurs. Recent increases in the population of lesser snow geese in North America, mainly due to improved feeding conditions on agricultural crops, have triggered widespread ecological changes on the breeding grounds, many thousands of kilometres away. On the salt marshes of Hudson Bay a team of biolo-
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12000
Figure 9-1.
Numbers of greylag geese in the Dollard from 1974 to 1994 showing (A) peak counts in autumn and (B) the mean number present in the winter based on monthly counts (December to February). The winter of 1974-1975 is coded as 1975, etc.
autumn maxima
A
Dec-Feb
B
goose numbers
10000
Greylags in the Dollard Greylags have not always been as abundant as they are today. Until a few decades ago these geese were declining due to year-round hunting. Once conservation measures had been instigated (closure of the spring hunt coupled with complete protection during the breeding season) there were signs of recovery. Around this time changes in agricultural practice began to provide more food of better quality for the geese (see Chapter 5). In just 20 years from 1970 to the early 1990s the number of greylag geese in Western Europe increased from 20,000 to 200,000. The greylags intensified their use of the traditional goose haunts such as the Dollard on the Dutch-German border, as well as spilling over into other sites.The Dollard, a 10,000 hectare estuarine area including mudflats and around 1,000 hectares of salt marsh, has been a haunt for greylags since at least the 1850s. Aside from the Westerschelde on the Belgian border, the Dollard is now the only brackish tidal area remaining in the Netherlands. In the 1960s at most a few hundred greylags could be found in the Dollard, but over the last 30 years an increase to peaks of 10,000 in autumn has been recorded by local bird watchers (see Fig. 9-1). The greylags roost in the Dollard, and forage on the surrounding farmland as well as the marsh foreshore.
8000 6000 4000 2000 0 5000
goose numbers
4000 3000 2000 1000 0 1975 '77 '79 '81 '83 '85 '87 '89 '91 '93
On the marsh, the geese make use of the aboveground parts of Festuca, Elymus, Puccinellia and Aster, as well as digging up the tubers and rhizomes of Scirpus and Spartina.The increase in goose numbers presented us with a ‘natural experiment’ to detect the impact of greatly increased grazing pressure on the vegetation.
85
GRAVES OWN
A natural experiment
THEIR
Our plan was to concentrate on effects related to the ‘grubbing’ of the geese. Fortunately, the local bird census group (Vogelgroep Dollard) had carried out systematic monthly counts since 1974, giving a reliable overview of greylag numbers. As greylags in spring prefer the fresh protein-rich growth above the ground, we will not consider spring goose numbers further. Fig. 8-1 shows both autumn peaks and the mean numbers of greylags in the Dollard during the winter months (December to February). After the initial increases, we seem to have been in a period of relative stability since 1985. One factor influencing the number of greylags that winter on the Dollard is the winter weather. In harsh winters such as 1978-1979, 1984-1985, and 1985-1986 most greylags left the area and headed south, but in the other winters several thousand geese remained. Peak numbers were observed in the mild winters of 1987-1988, 19881989 and 1989-1990. These were exceptionally mild winters (1988-1989 broke all Dutch records since 1707).
?
year
DIG
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1983
1991
N
Scirpus 0% < 10% 10 - 50% 50 - 100% 100 m
100 m Figure 9-2.
Distribution of Scirpus in 1983 and 1991 in a 400 metre wide, 33 hectare grid on the Dollard salt marsh. At the lower margin the grid abuts the dyke (seawall), and the outer (north) margin adjoins the tidal mudflats. The grid is bounded by channels previously dug to enhance accretion. The maps are based on ground surveys of strips 10 metres wide, later combined using GIS (geographic information system).
dyke (seawall) out to the marsh/mudflat interface, and the same sections were mapped again using similar procedures in 1991. During the summer months cattle are allowed to graze the marsh, so the vegetation over the first several hundred metres was a short turf without Scirpus.Towards the mudflat the cattle’s impact decreased. Over the years the number of cattle grazing the marsh has declined, so the belt of short vegetation has become narrower. In 1983 Scirpus formed dense stands along the outer perimeter of the salt marsh and there were also some patches further inland (see Fig. 9-2). By 1991 the dense Scirpus belt on the seaward side had disappeared altogether, and erosion had led to parts of the marsh reverting to mudflat. Further inland Scirpus had also declined markedly, being replaced by Phragmites or simply bare mud. A subsidiary plot of 14 hectares confirmed these changes. Scirpus stands (defined as areas with at least 10 percent cover) had declined from the original 20 percent of the total area (both seaward and inland) in 1983 to just 6 percent in 1991 (Fig. 9-3).
The Scirpus decline In 1981 a consortium of nature conservation bodies (Het Groninger Landschap and Natuurmonumenten) purchased a major portion of the Dollard salt marsh (470 of the 740 hectares on the Dutch side). Luckily, before implementing a management plan these authorities commissioned a vegetation mapping study by the Institute for Nature Management (RIN) in 1983. By repeating this work in 1991 I was able to examine vegetation changes in this critical phase with data both from the time that the number of greylags had just started their spectacular upsurge, and after eight years of heavy goose grazing. The initial vegetation mapping was conducted in sections extending from the
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Scirpus (47ha) A
Pagina 87
Spartina (94ha) B
20
area (%)
15
10
5
0
1983
1991
1983
1991
10-50% cover >50% cover
Figure 9-3.
Abundance as measured by percent ground cover of Scirpus (A) and Spartina (B) on the Dollard marshes (sample area indicated at top) from surveys in 1983 and 1991.
On the German side of the Dollard the Scirpus decline was even stronger. The first signs of shrinkage were noted in 1987, and in the mild winter of 1989-1990 greylag exploitation reached 7,500 goose-days per hectare in this area, a level 1.5 times the ‘damage threshold’ defined in an earlier study on the Krammer-Volkerak (in the 1960s, see above). The near disappearance of Scirpus on this side of the estuary seemed clearly related to goose grubbing. How this could happen was revealed by some smallscale experiments.
Figure 9-4.
87
GRAVES OWN THEIR DIG
Why did the greylags’ grubbing lead to overgrazing and a decline of their favourite food plants? Our observations suggested that the accessibility of Scirpus roots and tubers might be the key. We found attractive tubers were present anywhere from just a few centimetres below the surface down to a depth of more than 20 centimetres. Obviously the shallow tubers are easier for the greylags to reach. We decided to enhance the availability of the tubers by digging a short trench, so that the geese could work their way in from the side.
GREYLAGS
Experimental trenches
DO
The greylags indeed took advantage of this access trench (see Figs. 9-4 and 9-5) and grubbed their way into the Scirpus stand. By April, at the close of the exploitation phase when the geese switched to feeding on surface growth, 95 percent of the Scirpus biomass accessible from the trench had disappeared. We followed developments after this intensive grubbing episode, and recovery was slow. A full two years later the Scirpus stand still showed gaps.This small-scale experiment gave us insight into how goose grubbing could have affected the Scirpus stands lining the marsh-edge between 1983 and 1991, when the vegetation mapping exercises were undertaken. In addition, the complete
?
The trench experiment in a Scirpus stand. The top photo shows the control area (5 x 5 metres), fenced off from the geese during winter, as it looked in the following spring. The H-shaped trench dug in autumn is still visible. The lower photo shows an unfenced reference area where the geese have completely obliterated the Scirpus (the small pegs mark the 5 metre line).
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removal of the plants by goose grubbing exposed the unprotected marsh edge to wave action during winter storms. Extensive measurements with a level revealed that between 1984 and 1991-1992 erosion along the outer margin of the marsh was especially noticeable in a bare zone 25-50 metres wide around the remaining Scirpus stands.This zone was formerly covered by Scirpus, which had been grubbed away by geese. In contrast, erosion had been far less extensive around Phragmites stands.
28 October (1.86m2) 13 November (2.87m2) 20 November (4.53m2) 26 November (6.51m2)
Spartina takes a beating
1m
Figure 9-5.
Map of a 5 x 5 metre Scirpus stand similar to Figure 8-4 but now open to the geese throughout, and with an experimental trench (“H”) to facilitate goose grubbing. Shading indicates the grubbed area at successive dates in autumn: by 1 December the exploited area had spread in all directions from the trench.
1992 (n=600)
A
10
exclosed
survival (%)
80 60 accessible
40 20 0
1993 (n=200)
B
10 protected
80
survival (%)
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60 accessible
40 20 0
10 20 September
10 20 October
10 20 November
Figure 9-6.
Survival of Spartina seedlings depending on whether greylags could reach them or not. (A) In 1992 half of the plants were completely protected and all of these survived, in contrast to the complete removal of exposed plants (time scale along the bottom). (B) In 1993 survival of a naturally established stand was much higher in parts partially protected from geese by wire mesh placed in the marsh bed in September.
Spartina is another plant targeted by the greylags in winter and spring, again by grubbing for the rhizomes.To measure changes we carried out vegetation mapping as with the Scirpus plots, but this time using three rather than two grids. Spartina showed an even stronger decline than Scirpus. As with the Scirpus, stands of Spartina did not occur in the marsh zone near the dyke where cattle grazing in summer was most intense, although this is not a cause-andeffect relationship. At the outset of the vegetation mapping, Spartina was especially abundant in the more waterlogged central zone of the marsh, an area little used by the cattle. By 1991 these originally vigorous stands were partly replaced by species representing a later stage in the plant succession, but in other areas a retrogression towards earlier stages in succession was obvious, with an abundance of annuals. By ‘plant succession’ we refer to a gradual process whereby over time a given vegetation type is replaced by another (see also Chapter 39).The ‘rejuvenated’ areas with pioneer plant species coincided with areas that had previously been bare mud. Using exact reconstructions from a GIS (geographic information system) plot we found that what were bare patches in 1991 had been covered by Spartina in 1983. Another feature of these bare patches was their low elevation, so low that salty puddles remained after high tide. Here pioneer annuals such as Salicornia and Suaeda became established, but other species were absent. At first
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sight these depressions might also appear ideal starting points for the recovery of Spartina, but the greylags prevented this. Spartina germinated in these hollows almost every year, but in autumn these young plants were ripped out by greylags intent on the rhizomes, basal stems, and buds (see Fig. 9-6 and Box 2). Even if a plant had not been completely removed by goose grazing, its fate was sealed. If the Spartina stem is broken in these wet
places, the plant parts below the ground are cut off from their oxygen supply and will be unable to sprout again. These negative effects of aboveground damage also occur when greylags forage on fully developed clumps of Spartina. By simulating goose grazing in a greenhouse experiment we found that ‘grazed’ Spartina only survived if maintained in dry conditions, where oxygen could still reach the roots.
Box 1
HUMANS
AND
THE
DOLLARD
The history of the Dollard provides a perfect model of the complex interplay between people and coastal wetlands. This sac-like estuary situated in the Wadden Sea on the Dutch-German border was not formed until the 13th century, and the old land was successively eaten away until the Dollard reached its greatest extent in the early 1500s. As with the other major incursions on Dutch coasts in the Middle Ages (Zuiderzee, Middelzee and Lauwerszee), people had been more than just passive spectators. Both digging for peat and improved drainage for agriculture had caused the land to subside, making it more vulnerable to flooding by the sea. From the 16th centu-
ENVIRONMENT
ry onwards through a gradual process of embankment of recently deposited foreshore clays, the Dollard bay was won back from the sea. From at least 1740 active measures were undertaken to enhance accretion (ditching on the marsh) and the most recent area of reclaimed land was enclosed in 1924. The foreshore on the Dutch side (740 hectares) has since developed into the marsh we know today. Since 1954, when active management to maintain the land reclamation works on the foreshore ceased, there has been a slow but steady erosion of the marshland.
89
GRAVES OWN THEIR
Spartina anglica is a new member of our marsh flora that originated about a century ago on the south coast of England (hence the name) when the local Spartina maritima crossed with Spartina alterniflora unintentionally introduced from North America. The new hybrid was a vigorous invader, helped on its way by intentional planting along the coast to enhance the capture of silt in land reclamation. In the Wadden Sea (including the Dollard) the hybrid species was introduced in the 1920s. In Western Europe Spartina anglica is now dominant in the lower marsh zone and wherever drainage is poor. Like Scirpus the plant dies back in autumn, but the rhizomes, buds and basal stems retain relatively high carbohydrate concentrations making them attractive to geese.
DIG
Scirpus maritimus is a perennial growing up to 1.5 metres high in the Netherlands, which dies back in autumn (see Fig. 9-7). The starchy underground storage organs (see Fig. 9-3A) enable the plant to sprout anew in the spring. Carbohydrates (sugars) are vital ingredients for this regrowth and these easily digested components are valued by the geese as well. Scirpus is a pioneering species of young brackish habitats, and is often replaced by Phragmites as part of the natural succession process. This trend is also visible in the Dollard.
GREYLAGS
SPARTINA
DO
SCIRPUS
?
Box 2
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Figure 9-7.
Figure 9-8.
Scirpus in autumn, with a patch of Spartina in the right foreground.
Spartina in early September.
Goose impact in retrospect
Bay) or autumn (the Dollard) result in habitat degradation, but on vastly different scales. The question of the long-term impact of the greylags on the salt marsh is not easy to answer. Both Scirpus and Spartina are species confined to the young stages of estuarine and coastal marshes. Our observation that Phragmites had partially replaced these two seems to point to an ageing of the marsh with consequent plant succession. Even without greylag grazing Scirpus and Spartina would have declined over the years. Even the bare patches in Spartina’s former domain are temporary and will eventually be filled again, most likely by Phragmites, which thrives in the brackish Dollard.We must imagine that in the dim past when our coastal marshes were a dynamic and exposed habitat, there would always have been extensive belts of newly deposited silt clothed in pioneer plant communities. In those days, grubbing geese would have shifted their attention over the years depending on where Scirpus stands offered easy digging, and recovery in this mosaic of feeding patches would have been part of a natural cycle. In a sense our studies have underlined the loss of the carrying capacity of our coastal marshes which are now only a shadow of their former glory.
Grazing by greylag geese seems largely responsible for the disappearance of Scirpus on the salt marshes of the Dollard. The increased erosion accompanying goose-grubbing prevents recovery of the plants during the goose-free summer months. These impacts prevent an equilibrium situation between grazer and resource, despite the fact that grazing is strictly seasonal. This mismatch between bird populations and their natural food resources is to some extent the result of increasing food supplies from agriculture over the past few decades, which have contributed to the current population size of the greylag. It seems likely that this increase in goose numbers has led to a much more intensive seasonal exploitation of the natural habitats. Numbers are no longer limited by the naturally occurring food supplies that in conjunction with hunting used to impose a ceiling on goose numbers. The same syndrome of an ‘agricultural subsidy’ driving lesser snow goose numbers into the millions with consequent overexploitation of the subarctic marshes of Hudson Bay is the scenario favoured by the Canadian team in their long-term study. Concentrations of ‘grubbing’ geese, whether in spring (Hudson
References
1, 84, 85, 86
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REFERENCES
and management of coastal salt marshes in Europe. In Urbanska, K.M., Webb, N.R. & P.J. Edwards (eds). Restoration ecology and sustainable development: 286-322. Cambridge University Press, Cambridge.
1 Aerts, B.A., Esselink, P., & Helder, G.J.F. 1996. Habitat selection and diet composition of Greylag Geese Anser anser and Barnacle Geese Branta leucopsis during fall and spring staging in relation to management in the tidal marshes of the Dollard. Z. Ökol. Naturschutz 5: 65-75.
14 Balirwa, J.S., Chapman, C.A., Chapman, L.J., Cowx, I.G., Gaheb, K., Kaufman, L., LoweMcConnell, R.H., Seehuasen, O.,Wanink, J.H.,Welcomme, R.L. & F.Witte. 2003. Biodiversity and fishery sustainability in the Lake Victoria basin: an unexpected marriage? BioScience 53: 703-715.
2 Alerstam, T. 1990. Bird migration. Cambridge University Press, Cambridge. 3 Alerstam,T. & Å. Lindström. 1990. Optimal bird migration: the relative importance of time, energy and safety. In Gwinner, E. (ed.). Bird migration: physiology and ecophysiology: 331-351. Springer, Berlin.
15 Batt, B.D.J., Afton, A.D., Anderson, M.G., Ankney, C.D., Johnson, D.H., Kadlec, J.A. & G.L. Krapu (eds.).1992. Ecology and management of breeding waterfowl. University of Minnesota Press, Minneapolis.
4 Arnbom, T., Fedak, M.A. & I.L. Boyd. 1997. Factors affecting maternal expenditure in southern elephant seals during lactation. Ecology 78: 471-483.
16 Bazely, D.R. & R.L. Jefferies. 1997. Trophic interactions in Arctic ecosystems and the occurrence of a terrestrial trophic cascade. In Woodin, S.J. & M. Marquess (eds.). Ecology of Arctic environments: 183-208. Blackwell Science, Oxford.
5 Arnbom, T., Fedak, M.A., Boyd, I.L. & B.J. McConnell. 1993. Variation in weaning mass of pups in relation to maternal mass, postweaning fast duration, and weaned pup behaviour in southern elephant seals (Mirounga leonina) at South Georgia. Can. J. Zool. 71: 1772-1781. 6 Baerends, G.P. & R.H. Drent (eds.). 1982. The Herring Gull and its egg, II, The responsiveness to egg features. Behaviour 82: 1-416.
17 Beekman, J.H., Nolet, B.A. & M. Klaassen. 2003. Skipping swans: fuelling rates and wind conditions determine differential use of migratory stopover sites of Bewick’s swans Cygnus bewickii. Ardea 90: 437-460.
7 Baird, D, Asmus, H. & R. Asmus. 2004. Energy flow of a boreal intertidal ecosystem, the SyltRømø Bight. Mar. Ecol. Prog. Ser. 279: 45-61.
18 Beintema, A.J. & G.H.Visser. 1989.The effect of weather on the time budgets and development of chicks of meadow birds. Ardea 77: 181-192.
8 Baker, J.D. & C.W. Fowler. 1992. Pup weight and survival of northern fur seals Callorhinus ursinus. J. Zool., Lond. 227: 231-238.
19 Beintema, A.J. & G.J.D.M. Müskens. 1987. Nesting success of birds breeding in Dutch agricultural grasslands. J. Appl. Ecol. 24: 743758.
9 Bakker, E.S. & H. Olff. 2003. Impact of differentsized herbivores in recruitment opportunities for subordinate herbs in grassland. J. Veg. Sci. 14: 465-474.
20 Beintema, A.J. & N. Drost. 1986. Migration of the Black-tailed Godwit. Le Gerfaut 76: 37-62. 21 Beintema, A.J., Beintema-Hietbrink, E.J. & G.J.D.M. Müskens. 1985. A shift in the timing of breeding in meadow birds. Ardea 73: 83-89.
10 Bakker, E.S., Olff, H., Boekhoff, M., Gleichman, J.M. & F. Berendse. 2004a. Impact of herbivores on nitrogen cycling: contrasting effects of small and large species. Oecologia 138: 91-101.
22 Beintema, A.J., Moedt, O. & D. Ellinger. 1995. Ecologische atlas van de Nederlandse weidevogels. Schuyt & Co., Haarlem.
11 Bakker, E.S., Olff, H.,Vandenberghe, C., de Maeyer, K., Smit, R. & J.M. Gleichman. 2004b. Ecological anachronisms in the recruitment of temperate light-demanding tree species in wooded pastures. J. Appl. Ecol. 41: 571-582.
23 Blaxter, K. 1989. Energy metabolism in animals and man. Cambridge University Press, Cambridge. 24 Bokdam, J. 2001. Effects of browsing and grazing on cyclic succession in nutrient-limited ecosystems. J.Veg. Sci. 12: 875-886.
12 Bakker, J.P., Esselink, P., Dijkema, K.S.,Van Duin, W.E. & D.J. de Jong. 2002. Restoration of salt marshes. Hydrobiol. 478: 29-51.
25 Bos, D. & J. Stahl 2003. Creating new foraging opportunities for Dark-bellied Brent Geese Branta bernicla and Barnacle Geese Branta leucopsis in spring – insights from a largescale experiment. Ardea 91: 153-165.
13 Bakker, J.P., Esselink, P., van der Wal, R. & K.S. Dijkema. 1997. Options for restoration
302
27-01-2006
14:46
Pagina 303
38 Chitty, D. 1996. Do lemmings commit suicide? Beautiful hypotheses and ugly facts. Oxford University Press, New York.
26 Bos, D., Bakker, J.P., de Vries,Y. & S. van Lieshout. 2002. Long-term vegetation changes in experimentally grazed and ungrazed backbarrier marshes in the Wadden Sea. Appl. Veg. Sci. 5: 45-54. 27 Bos, D., van de Koppel, J. & F.J.Weissing 2004. Dark-bellied Brent Geese aggregate to cope with increasing levels of primary production. Oikos 70: 485-496.
39 Clausen, P., Green, M. & T. Alerstam. 2003. Energy limitations for spring migration and breeding: the case of brent geese Branta bernicla tracked by satellite telemetry to Svalbard and Greenland. Oikos 103: 426445.
28 Bossema, I. & R.R. Burgler. 1980. Communication during monocular and binocular looking in European Jays (Garrulus g. glandarius). Behaviour 74: 274-283.
40 Craig, M.P. & T.J. Ragen. 1999. Body size, survival, and decline of juvenile Hawaiian monk seals, Monachus schauinslandi. Mar. Mamm. Sci. 15: 786-809.
29 Both, C., Tinbergen, J.M. & M.E.Visser. 2000. Adaptive density dependence of avian clutch size. Ecology 81: 3391-3403.
41 Daan, S., Beersma, D.G.M. & A.A. Borbély. 1984. Timing of human sleep: recovery process gated by a circadian pacemaker. Am. J. Physiol. 246: R161-R178.
30 Brown, J.H.,Whitham, T.G., Morgan Ernest, S.K. & C.A. Gehring. 2001. Complex species interactions and the dynamics of ecological systems: long-term experiments. Science 293: 643-650.
42 Daan, S., Deerenberg, C. & C. Dijkstra. 1996. Increased daily work precipitates natural death in the kestrel. J. Anim. Ecol. 65: 539544.
31 Bryant, D.M. & K.R.Westerterp. 1983.Time and energy limits to brood size in house martins (Delichon urbica). J.Anim. Ecol. 52: 905-925.
43 Daan, S., Dijkstra, C. & J.M. Tinbergen. 1990. Family planning in the Kestrel (Falco tinnunculus): the ultimate control of covariation of laying date and clutch size. Behaviour 114: 83-116.
32 Bryant, D.M. & P. Tatner. 1991. Intraspecies variation in energy expenditure: correlates and constraints. Ibis 133: 236-245.
44 Darwin, C. 1859. On the origin of species by means of natural selection. John Murray, London.
33 Burton, H.R., Arnbom, T., Boyd, I.L., Bester, M., Vergani, D. & I.Wilkinson. 1997. Significant differences in weaning mass of southern elephant seals from five subAntarctic islands in relation to population declines. In: Battaglia, B., Valencia, J. & D.W.H. Walton (eds.). Antarctic Communities: Species, Structure and Survival: 335-338. Cambridge University Press, Cambridge.
45 Darwin, C. 1871. The descent of man and selection in relation to sex. John Murray, London. 46 De Goeij, P., Luttikhuizen, P.C., van der Meer, J. & T. Piersma. 2001. Facilitation on an intertidal mudflat: the effect of siphon nipping by flatfish on burying depth of the bivalve Macoma balthica. Oecologia 126: 500-506. 47 De Leeuw, J.J. 1999. Food intake rates and habitat segregation of tufted duck Aythya fuligula and scaup Aythya marila exploiting Zebra mussels Dreissena polymorpha. Ardea 87: 15-31.
34 Butler, P.J., Bishop, C.M. & A.J.Woakes. 2003. Chasing a wild goose: posthatch growth of locomotion muscles and behavioural physiology of migration of an Arctic goose. In Berthold, P., Gwinner, E. & E. Sonnenschein (eds.). Avian Migration: 527542. Springer-Verlag, Berlin Heidelberg.
48 De Leeuw, J.J., Butler, P.J.,Woakes, A.J. & F. Zegwaard. 1998. Body cooling and its energetic implications for feeding and diving of Tufted Ducks. Physiol. Zool. 71: 720-730.
35 Carlini, A.R., Panarello, H.O., Marquez, M.E.I., Daneri, G.A. & G.E. Soave. 2000. Energy gain and loss during lactation and postweaning in southern elephant seal pups (Mirounga leonina) at King George Island. Polar Biol. 23: 437-440.
49 De Leeuw, J.J., van Eerden, M.R. & G.H.Visser. 1999. Wintering tufted ducks Aythya fuligula diving for Zebra mussels Dreissena polymorpha balance feeding costs within narrow margins of their energy budget. J. Avian Biol. 30: 182-192.
36 Chamberlain, C.P., Bensch, S., Feng, X., Åkesson, S. & T. Andersson. 2000. Stable isotopes examined across a migratory divide in Scandinavian willow warblers (Phylloscopus trochilus trochilus and Phylloscopus trochilus acredula) reflect their African winter quarters. Proc. Roy. Soc. London B 267: 43-48.
50 De Waal, F. 1996. Good natured: the origins of right and wrong in humans and other animals. Harvard University Press, Cambridge.
37 Chitty, D. 1938. A laboratory study of pellet formation in the short-eared Drol. Asió flammeus, Proc. zool. Soc. A 108: 267-287.
52 Deerenberg, C., Pen, I., Dijkstra, C., Arkies, B-J, Visser, G.H. & S. Daan. 1995. Parental energy expenditure in relation to manipu-
51 Deerenberg, C., Apanius,V., Daan, S. & N. Bos. 1997. Reproductive effort decreases antibody responsiveness. Proc. Roy. Soc. London B 264: 1021-1029.
303
REFERENCES
*Ontwerp def.
*Ontwerp def.
27-01-2006
14:46
Pagina 304
lated brood size in the European Kestrel Falco tinnunculus. Zool. Anal. Complex Syst. 99: 39-48.
66 Ebbinge, B.S. 1989. A multifactorial explanation for variation in breeding performance of Brent Geese Branta bernicla. Ibis 131: 196-204.
53 Dietz, M.W. & M. van Kampen. 1994. The development of thermoregulation in turkey and guinea fowl hatchlings: Similarities and differences. J. Comp. Physiol. B 164: 69-75.
67 Ebbinge, B.S. 1991. The impact of hunting on mortality rates and spatial distribution of geese wintering in the western palearctic. Ardea 79: 197-210.
54 Dietz, M.W. & R.E. Ricklefs. 1997. Growth rate and maturation of skeletal muscles over a size range of galliform birds. Physiol. Zool. 70: 502-510.
68 Ebbinge, B.S. & B. Spaans. 1995. The importance of body reserves accumulated in spring staging areas in the temperate zone for breeding in Dark-bellied Brent Geese Branta b. bernicla in the High Arctic. J. Avian Biol. 26: 105-113.
55 Dietz, M.W., Dekinga, A., Piersma, T. & S.Verhulst. 1999. Estimating organ size in small migrating shorebirds with ultrasonography: an intercalibration exercise. Physiol. Biochem. Zool. 72: 28-37.
69 Ebbinge, B.S., Berrevoets, C., Clausen, P., Ganter, B., Günther, K., Koffijberg, K., Mahéo, R., Rowcliffe, M., St Joseph, A.K.M., Südbeck, P. & E.E. Syroechkovsky Jr. 1999. Dark-bellied Brent Goose, Branta bernicla bernicla. In: Madsen, J., Cracknell, G. & A.D. Fox (eds.). Goose populations of the Western Palearctic: 284-297. Wetlands International, Wageningen.
56 Dietz, M.W., Drent, R.H. & R.E. Ricklefs. 1995. Biphasic development of metabolic rate in young precocial birds: a possible physiological basis. In: Dietz, M.W. Development of metabolism and thermoregulation in galliforms. Effects of body mass, growth rate and functional maturity: 57-76. PhD thesis, University of Utrecht, Utrecht.
70 Ebbinge, B.S., Heesterbeek, J.A.P., Ens, B.J. & P.W. Goedhart. 2002. Density dependent population limitation in Dark-bellied Brent Geese Branta b. bernicla. Avian Sci. 2: 63-75.
57 Dijkstra, C., Bult, A., Bijlsma, S., Daan, S., Meijer, T. & M. Zijlstra. 1990. Brood size manipulations in the kestrel (Falco tinnunculus): effects on offspring and parent survival. J. Anim. Ecol. 59: 269-285.
71 Ebbinge, B.S., van Biezen, J.B. & H. van der Voet. 1991. Estimation of annual adult survival rates of Barnacle Geese Branta leucopsis using multiple resightings of marked individuals. Ardea 79: 73-112.
58 Dijkstra, C., Daan, S. & I. Pen. 1998. Fledging sex ratios in relation to brood size in size-dimorphic altricial birds. Behav. Ecol. 9: 287-296.
72 Eichhorn, G., Afanasyev,V., Drent, R.H. & H. van der Jeugd. 2005. Spring stopover routines in Russian Barnacle Geese Branta leucopsis tracked by resightings and geolocation. Ardea 93.
59 Dircksen, R., J.B. Hulscher, H. Rittinghaus & G. Schnakenwinkel. 1975. Haematopus ostralegus, Austernfischer. In: Glutz von Blotzheim, Bauer & Bezzel (eds.) Handbuch der Vögel Mitteleuropas: 26-86. Akademische Verlagsgesellschaft Wiesbaden.
73 Ellis H.I. & G.W. Gabrielsen. 2002. Energetics of free-ranging seabirds. In Schrieber, E.A. & J. Burger (eds.). Biology of Marine Birds: 359407. CRC Press, Boca Raton.
60 Drent, J., van Marken Lichtenbelt,W.D. & M. Wikelski. 1999. Effects of foraging mode and season on the energetics of the marine iguana Amblyrhynchus cristatus. Funct. Ecol. 13: 493-499.
74 Engelhard, G.H., Baarspul, A.N.J., Broekman, M., Creuwels, J.C.S. & P.J.H. Reijnders. 2002. Human disturbance, nursing behaviour, and lactational pup growth in a declining southern elephant seal (Mirounga leonina) population. Can. J. Zool. 80: 1876-1886.
61 Drent, P.J. & J.W.Woldendorp. 1989. Acid rain and eggshells. Nature 339: 431. 62 Drent, R.H. & S. Daan 1980. The prudent parent: energetic adjustments in avian breeding. Ardea 68: 225-252.
75 Engelhard, G.H., Brasseur, S.M.J.M., Hall, A.J., Burton, H.R. & P.J.H. Reijnders. 2002. Adrenocortical responsiveness in southern elephant seal mothers and pups during lactation and the effect of scientific handling. J. Comp. Physiol. B 172: 315-328.
63 Drent, R. & T. Piersma. 1990. An exploration of the energetics of leap-frog migration in arctic breeding waders. In Gwinner, E. (ed.). Bird migration: physiology and ecophysiology: 399-412. Springer, Berlin.
76 Engelhard, G.H., Hall, A.J., Brasseur, S.M.J.M. & P.J.H. Reijnders. 2002. Blood chemistry in southern elephant seal mothers and pups during lactation reveals no effect of handling. Comp. Biochem. Physiol.A 133: 367-378.
64 Drent, R., Both, C., Green, M., Madsen, J. & T. Piersma. 2003. Pay-offs and penalties of competing migratory schedules. Oikos 103: 274-292. 65 Ebbinge, B.S. 1985. Factors determining the population size of Arctic-breeding geese wintering in Western Europe. Ardea 73: 121-128.
77 Engelhard, G.H., van den Hoff, J., Broekman, M., Baarspul, A.N.J., Field, I., Burton, H.R. &
304
27-01-2006
14:46
Pagina 305
91 Forbes, S. 2005. A natural history of families. Princeton University Press, New Jersey.
P.J.H. Reijnders. 2001. Mass of weaned elephant seal pups in areas of low and high human presence. Polar Biol. 24: 244-251.
92 Fossey, D. 1983. Gorillas in the mist. Houghton Mifflin Company, Boston.
78 Ens, B.J. 1998. Love thine enemy? Nature 391: 635637.
93 Geissler, A. 1889. Beiträge zur Frage des Geschlechts verhältnisses der Geborenen. Zeitschift des K. Sachsischen Statistischen Bureaus.
79 Ens, B.J., Choudhury, S. & J.M. Black. 1996. Mate fidelity and divorce in monogamous birds. In: J.M. Black (ed.). Partnerships in Birds: 344-395. Oxford University Press, Oxford.
94 Goldschmidt, T. 1998. Darwin’s dreampond, drama in Lake Victoria. MIT Press, Cambridge, Massachusetts.
80 Ens, B.J., Kersten, M., Brenninkmeijer, A. & J.B. Hulscher. 1992. Territory quality, parental effort and reproductive success of oystercatchers (Haematopus ostralegus). J. Anim. Ecol. 61: 703-715.
95 Goss-Custard, J.D., le V. dit Durell, S.E.A., Goater, C.P., Hulscher, J.B., Lambeck, R.H.D., Meininger, P.L. & J. Urfi. 1996. How oystercatchers survive the winter. In: J.D.Goss-Custard (ed). The Oystercatcher: from individuals to populations: 133-154. Oxford University Press, Oxford.
81 Ens, B.J., Piersma, T.,Wolff,W.J. & L. Zwarts. (eds.). 1990. Homeward bound: problems waders face when migrating from the Banc d’Arguin, Mauritania, to their northern breeding grounds in spring. Ardea 78: 1-364.
96 Graveland, J., van der Wal, R., van Balen, J.H. & A.J. van Noordwijk. 1994. Poor reproduction in forest passerines from decline of snail abundance on acidified soils. Nature 368: 446-448.
82 Ens, B.J., Smaal, A.C. & J. de Vlas. 2004. The effects of shellfish fishery on the ecosystems of the Dutch Wadden Sea and Oosterschelde (Final Report EVA II) Alterra, Wageningen.
97 Graveland, J.R. & J.E. Berends. 1997.Timing of the calcium uptake and effect of calcium deficiency on behaviour and egg-laying in captive great tits, Parus major. Physiol. Zool. 70: 74-84.
83 Ens, B.J.,Weissing, F.J. & R.H. Drent. 1995. The despotic distribution and deferred maturity: two sides of the same coin. American Nat. 146: 625-650.
98 Graveland, J.R. & R. van der Wal. 1996.Decline of snail abundance by soil acidification causes eggshell defects in forest passerines. Oecologia 105: 351-360.
84 Esselink, P., Dijkema, K.S. & L.F.M. Fresco. 2002. Vegetation change in a man-made salt marsh affected by a reduction in both grazing and drainage. Appl.Veg. Sci. 5: 1732.
99 Graveland, J.R. & R.H. Drent. 1996. Calcium availability limits breeding success of passerines on poor soils. J.Anim. Ecol. 66: 279-288. 100 Graveland, J.R. & T. van Gijzen. 1994. Arthropods and seeds are not sufficient as calcium sources for shell formation and skeletal growth in passerines. Ardea 82: 299-314.
85 Esselink, P., Helder, G.J.F., Aerts, B.A. & K. Gerdes. 1997. The impact of grubbing by Greylag Geese (Anser anser) on the vegetation dynamics of a tidal marsh. Aquatic Botany 55: 261-279.
101 Green, M., Alerstam, T., Clausen, P., Drent, R. & B.S. Ebbinge. 2002. Dark-bellied Brent Geese Branta bernicla bernicla as recorded by satellite telemetry, do not minimize flight distance during spring migration. Ibis 144: 106-121.
86 Esselink, P., Zijlstra,W., Dijkema, K.S. & R. van Diggelen. 2000. The effects of decreased management on plant species distribution patterns in a salt marsh nature reserve in the Wadden Sea. Biol. Conserv. 93: 61-76.
102 Gwinner, E. & B. Helm. 2003. Circannual and circadian contributions to the timing of avian migration. In Berthold, P., Gwinner, E. & E. Sonnenschein (eds.). Avian Migration: 81-95. Springer-Verlag, Berlin Heidelberg.
87 Etherington, G. & B. Small. 2003.Taxonomy and identification of atlas flycatcher – a potential British vagrant. Birding World 16: 252-256. 88 Fedak, M.A., Arnbom, T. & I.L. Boyd. 1996. The relation between the size of elephant seal mothers, the growth of their pups, and the use of maternal energy, fat, and protein during lactation. Physiol. Zool. 69: 887911.
103 Hall, A.J., McConnell, B.J. & R.J. Baker. 2001. Factors affecting first-year survival in grey seals and their implications for life history strategy. J. Anim. Ecol. 70: 138-149. 104 Hanley, G. 1971. Warriors and strangers. Hamish Hamilton, London.
89 Fisher, R.A. 1930. The Genetical Theory of Natural Selection. Oxford University Press, Oxford.
105 Hedenström, A., Alerstam, T. & S. Åkesson. 2003. Ecology of long-distance movements: migration and orientation performance. Oikos 103: 243-448.
90 Forbes, L.S. & R.C.Ydenberg. 1992. Sibling rivalry in a variable environment. Theor. Popul. Biol. 41: 135-160.
305
REFERENCES
*Ontwerp def.
*Ontwerp def.
27-01-2006
14:46
Pagina 306
118 Jackson, J.B.C. Kirby, M.X., Berger,W.H., Bjorndal, K.A., Botsford, L.W., Bourque, B.J., Bradbury, R.H., Cooke, R., Erlandson, J., Estes, J.A., Hughes, T.P., Kidwell, S., Lange, C.B., Lenihan, H.S., Pandolfi, J.M., Peterson, C.H., Steneck, R.S., Tegner, M.J. & Warner, R.R. 2001 Historical overfishing and the recent collapse of coastal ecosystems. Science 293: 629-638.
106 Heg, D. & M. van der Velde. 2001. Effects of territory quality, food availability and sibling competition on the fledging success of Oystercatchers (Haematopus ostralegus). Behav. Ecol. Sociobiol. 49: 157-169. 107 Heg, D. & R. van Treuren. 1998. Female-female cooperation in polygynous Oystercatchers. Nature 391: 687-691. 108 Heg, D., Bruinzeel, L.W. & B.J. Ens. 2003. Fitness consequences of divorce in the Oystercatcher, Haematopus ostralegus. Anim. Behav. 66: 175-184.
119 Kamermans, P. 1994. Nutritional value of solitary cells and colonies of Phaeocystis sp. for the bivalve Macoma balthica (L.). Ophelia 39: 3544.
109 Heg, D., Dingemanse, N.J., Lessells, C.M. & A.C. Mateman. 2000. Parental correlates of offspring sex ratio in Eurasian Oystercatchers. Auk 117: 980-986.
120 Kamermans, P. 1994. Similarity in food source and timing of feeding in deposit- and suspension-feeding bivalves. Mar. Ecol. Prog. Ser. 104: 63-75.
110 Heg, D., Ens, B.J., Burke, T., Jenkins, L. & J.P. Kruijt. 1993. Why does the typically monogamous Oystercatcher (Haematopus ostralegus) engage in extra-pair copulations? Behaviour 126: 247-289.
121 Kamermans, P. & H.J. Huitema. 1994. Shrimp (Crangon crangon L.) browsing upon siphon tips inhibits feeding and growth in the bivalve Macoma balthica (L.). J. Exp. Mar. Biol. Ecol. 175: 59-75.
111 Heg, D., Ens, B.J., van der Jeugd, H. & L.W. Bruinzeel. 2000. Local dominance and territorial settlement of nonbreeding oystercatchers. Behaviour 137: 473-530.
122 Kamermans, P., van der Veer, H.W., Karszmarski, L. & G.W. Doeglas. 1992. Competition in deposit- and suspension-feeding bivalves: experiments in controlled outdoor environments. J. Exp. Mar. Biol. Ecol. 162: 113-135.
112 Helbig, A.J. 1996. Genetic basis, mode of inheritance and evolutionary changes of migratory directions in Palearctic warblers (Aves: Sylviidae). J. Exp. Biol. 199: 49-55.
123 Klaassen, M. 1994. Growth and energetics of tern chicks from temperate and polar environments. Auk 111: 525-544.
113 Hindell, M.A., Bryden, M.M. & H.R. Burton. 1994. Early growth and milk composition in southern elephant seals (Mirounga leonina). Aust. J. Zool. 42: 723-732.
124 Klaassen, M. & R. Drent. 1991. An analysis of hatchling resting metabolism: in search of ecological correlates that explain deviations from allometric relations. Condor 93: 612-629.
114 Hindell, M.A., McConnell, B.J., Fedak, M.A., Slip, D.J., Burton, H.R., Reijnders, P.J.H. & C.R. McMahon. 1999. Environmental and physiological determinants of successful foraging by naive southern elephant seal pups during their first trip to sea. Can. J. Zool. 77: 1807-1821.
125 Klaassen, M., Beekman, J.H., Kontiokorpi, J., Mulder, R.J.W. & B.A. Nolet. 2004. Migrating swans profit from favourable changes in wind conditions at low altitude. J. Orn. 145: 142-151.
115 Hindell, M.A., Slip, D.J. & H.R. Burton. 1994. Possible causes of the decline of southern elephant seal populations in the southern Pacific and southern Indian Oceans. In: Le Boeuf, B.J. & R.M. Laws (eds.). Elephant Seals: Population Ecology, Behavior, and Physiology: 6684. University of California Press, Berkeley and Los Angeles.
126 Klasing, K.C. 1998. Comparative avian nutrition. CAB International, Wallingford. 127 Klein, J. & N. Takahata. 2002. Where do we come from? The molecular evidence for human descent. Springer Verlag, Berlin. 128 Komdeur, J. 1994. Conserving the Seychelles warbler Acrocephalus seychellensis by translocation from Cousin Island to the islands of Aride and Cousine. Biol. Conserv. 76: 143-152.
116 Hulscher, J.B., K.-M. Exo, & N.A. Clark. 1996. Why do oystercatchers migrate? In: J.D.Goss-Custard (ed). The Oystercatcher: from individuals to populations: 155-185. Oxford University Press, Oxford.
129 Komdeur, J. 2003. Daughters on request: about helpers and egg sexes in the Seychelles warbler. Proc. Roy. Soc. Lond. Ser. B 270: 3-11.
117 Hummel, H. 1985. Food intake of Macoma balthica (Mollusca) in relation to seasonal changes in its potential food on a tidal flat in the Dutch Wadden Sea. Neth. J. Sea Res. 31: 7181.
130 Komdeur, J. 2003. Mother knows best: sons or daughters? Behav. Ecol. 15: 8-10. 131 Komdeur, J. & I. Pen. 2002. Adaptive sex allocation in birds: the complexities of linking theory and practice. Phil.Trans. Roy. Soc.(Lond.) B 357: 373-380.
306
27-01-2006
14:46
Pagina 307
147 Machmer, M. & R.C.Ydenberg. 1989. Weather and osprey foraging energetics. Can. J. Zool. 68: 40-43.
132 Komdeur, J., Magrath, M.S.L. & S. Krakchow 2002. Pre-ovulation control of hatchling sex ratio in the Seychelles Warbler. Proc. Roy. Soc. Lond. B 269:1067-1072.
148 Madsen, J. & M. Klaassen (in press) Pre-breeding body stores determine reproductive success and survival in a high-Arctic migratory goose.
133 Komdeur, J., Daan, S., Tinbergen, J. & C. Mateman. 1997. Extreme adaptive modification in sex ratio of the Seychelles warbler’s eggs. Nature 385: 522-525.
149 Malecki, R.A., Batt, B.D.J. & S.E. Shaeffer. 2001. Spatial and temporal distribution of Atlantic population Canada Geese. J.Wildl. Mgmnt. 65: 242-247.
134 Komdeur, J., Piersma, T., Kraaijeveld, K., Kraaijeveld-Smith, F. & D.S. Richardson. 2004. Why Seychelles warblers fail to recolonise nearby islands: unwilling or unable to fly there? Ibis 146: 298-302.
150 Masman, D., Daan, S. & C. Dijkstra. 1988. Time allocation in the kestrel (Falco tinnunculus) and the principle of energy minimization. J. Anim. Ecol. 57: 411-432.
135 Krebs, C.J. 1972. Ecology, the experimental analysis of distribution and abundance. Harper International, New York. 136 Krebs, J.R. & N.B. Davies. 1978. Behavioural ecology, an evolutionary approach. Blackwell Scientific, Oxford.
151 Masman, D., Daan, S. & H.J.A. Beldhuis. 1988. Ecological energetics of the kestrel: daily energy expenditure throughout the year based on time-energy budget, food intake and doubly-labelled water methods. Ardea 76: 64-81.
137 Kvist, A. & Å. Lindström. 2003. Gluttony in migratory waders-unprecedented energy assimilation rates in vertebrates. Oikos 103: 397-402.
152 Masman, D., Dijkstra, C., Daan, S. & A. Bult. 1989. Energetic limitation of avian parental effort: field experiments in the kestrel (Falco tinnunculus). J. Evol. Biol. 2: 435-455.
138 Lack, D. 1954. The natural regulation of animal numbers. Oxford University Press, London. 139 Lack, D. 1966. Population studies of birds. Clarendon Press, Oxford.
153 Maynard Smith, J. 1983. Evolution and the theory of games. Cambridge University Press, Cambridge.
140 Loonen, M.J.J.E., Bruinzeel, L.W., Black, J.M. & R.H. Drent. 1999. The benefit of large broods in barnacle geese: a study using natural and experimental manipulations. J. Anim. Ecol. 68: 753-768.
154 McConnell, B., Fedak, M., Burton, H.R., Engelhard, G.H. & P.J.H. Reijnders. 2002. Movements and foraging areas of naïve, recently weaned southern elephant seal pups. J. Anim. Ecol. 71: 65-78.
141 Loonen, M.J.J.E., Oosterbeek, K. & R.H. Drent. 1997. Variation in growth of young and adult size in barnacle geese Branta leucopsis: Evidence for density dependence. Ardea 79: 253-260.
155 McMahon, C.R., Bester, M.N., Burton, H.R., Hindell, M.A. & C.J.A. Bradshaw. 2005. Population status, trends and a re-examination of the hypotheses explaining the recent declines of the southern elephant seal Mirounga leonina. Mammal Rev. 35: 82100.
142 Loonen, M.J.J.E., Tombre, I.M. & F. Mehlum. 1998. Development of an arctic barnacle goose colony: Interactions between density and predation. Norsk Polarinst. Skr. 200: 67-79. 143 Loth, P.E. 1999. The vegetation of Manyara: scale-dependent states and transitions in the African Rift Valley. Report, Wageningen Agricultural University, Wageningen.
156 McMahon, C.R., Burton, H.R. & M.N. Bester. 2000. Weaning mass and the future survival of juvenile southern elephant seals, Mirounga leonina, at Macquarie Island. Antarct. Sci. 12: 149-153.
144 Loth, P.E. & H.H.T. Prins. 1986. Spatial patterns of the landscape and vegetation of Lake Manyara National Park, Tanzania. ITC Journ. 1986(2): 115-130 (includes vegetation map 1:50,000).
157 McNaughton, S.J. 1979. Grassland-herbivore dynamics. In Sinclair, A.R.E. & M. NortonGriffiths (eds.). Serengeti: Studies of ecosystem dynamics in a tropical savanna: 46-81 University of Chicago Press, Chicago.
145 Loth, P.E., de Boer, F., Heitkönig, I.M.A. & H.H.T. Prins. (in press). Germination strategy of Acacia tortilis trees in a heterogeneous East Africa savanna environment. J.Tropical Ecol.
158 Meijer, T. & R. Drent. 1999. Re-examination of the capital and income dichotomy in breeding birds. Ibis 141: 399-414. 159 Meijer, T., Dijkstra, C. & S. Daan. 1988. Female condition and reproduction. Effects of food manipulation in free-living and captive kestrels. Ardea 76: 141-154.
146 Lundberg, A. & R.V. Alatalo. 1992. The pied flycatcher. T & AD Poyser, London.
307
REFERENCES
*Ontwerp def.
*Ontwerp def.
27-01-2006
14:46
Pagina 308
160 Meijer, T., Masman, D., & S. Daan. 1989. Energetics of reproduction in female kestrels. Auk 106: 549-559.
174 Pen, I.,Weissing, F-J. & S. Daan. 1999. Seasonal sex ratio trend in the European Kestrel: an ESS analysis. Amer. Nat. 153: 384-397.
161 Moussaieff Masson, J. & S. McCarthy. 1995. When elephants weep: the emotional lives of animals. Delacorte Press, New York.
175 Phillips, R.A., Silk, J.R.D., Croxall, J.P., Afanasjev, V. & D.R. Briggs. 2004. Accuracy of geolocation estimates for flying seabirds. Mar. Ecol. Progr. Ser. 266: 265-272.
162 Nolet, B.A. & F. Rosell. 1994. Territoriality and time budgets in beavers during sequential settlement. Can. J. Zool. 72: 1227-1237.
176 Piersma, T. 2002. Energetic bottlenecks and other design constraints in avian annual cycles. Integr. Comp. Biol. 42: 51-67.
163 Nolet, B.A. & J.M. Baveco. 1996. Development and viability of a translocated beaver Castor fiber population in the Netherlands. Biol. Conserv. 75: 125-137.
177 Piersma, T. & Å. Lindström. 1997. Rapid reversible changes in organ size as a component of adaptive behaviour. Trends in Ecology and Evolution 12: 134-138.
164 Nolet, B.A. & R.H. Drent. 1998. Bewick’s swans refuelling on pondweed tubers in the Dvina Bay (White Sea) during their spring migration: first come, first served. J. Avian Biol. 29: 574-584.
178 Piersma, T., De Goeij, P. & I. Tulp. 1993. An evaluation of intertidal feeding habitats from a shorebird perspective: towards relevant comparisons between temperate and tropical mudflats. Neth. J. Sea Res. 31: 503-512.
165 Nolet, B.A., Broekhuizen, S., Dorresteijn, G.M. & K.M. Rienks. 1997. Infectious diseases as main causes of mortality to beavers Castor fiber after translocation to the Netherlands. J. Zool. 241: 35-42.
179 Piersma, T., Koolhaas, A., Dekinga, A., Beukema, J.J. & K. Essink. 2001. Long-term indirect effects of mechanical cockle-dredging on intertidal bivalve stocks in the Wadden Sea. J. Appl. Ecol. 38: 976-990.
166 Nolet, B.A., Dijkstra,V.A.A. & D. Heidecke. 1994. Cadmium in beavers translocated from the Elbe River to the Rhine/Meuse estuary, and the possible effect on population growth rate. Arch. Environ. Contam. Toxicol. 27: 154-161.
180 Pott, R. & Hüppe, J. 1993. Die Hudenlandschaften Nordwestdeutschlands. 181 Prins, H.H.T. 1996. Ecology and behaviour of the African Buffalo, social inequality and decision making. Chapman & Hall, London.
167 Nolet, B.A., Hoekstra, A. & M.M. Ottenheim. 1994. Selective foraging on woody species by the beaver Castor fiber and its impact on a riparian willow forest. Biol. Conserv. 70: 117-128.
182 Prins, H.H.T. & F.J.Weyerhaeuser. 1987. Epidemics in populations of wild ruminants: anthrax, and impala, rinderpest and buffalo in Lake Manyara National Park, Tanzania. Oikos 49: 28-38.
168 Nolet, B.A., van der Veer, P., Evers, E.G.J. & M.M. Ottenheim. 1995. A linear programming model of diet choice of free-living beavers. Neth. J. Zool. 45: 315-337.
183 Prins, H.H.T. & H.P.Van der Jeugd. 1993. Herbivore crashes and woodland structure in East Africa. J. Ecol. 81: 305-314.
169 Olff, H., de Leeuw, J., Bakker, J.P., Platerink, R.J., van Wijnen, H.J. & W. de Munck. 1997. Vegetation succession and herbivory in a salt marsh: changes induced by sea-level rise and silt deposition on elevational gradients. J. Ecol. 85: 799-814.
184 Prins, H.H.T. & I. Douglas-Hamilton. 1990. Stability in a multi-species assemblage of large herbivores in Africa. Oecologia 83: 392-400. 185 Prop, J. 2004. Food finding: on the trail to successful reproduction in migratory geese. Disser-tation, University of Groningen, Groningen.
170 Olff, H., Ritchie, M.E. & H.H.T. Prins. 2002. Global environmental determinants of diversity in large herbivores. Nature 415: 901-905.
186 Prop, J. & C. Deerenberg 1991. Spring staging in brent geese Branta bernicla: feeding constraints and the impact of diet on the accumulation of body reserves. Oecologia 87: 19-28.
171 Olff, H.,Vera, F.W.M., Bokdam, J., Bakker, E.S., Gleichman, J.M., De Maeyer, K. & R. Smit. 1999. Associational resistance of plants to herbivory may lead to shifting mosaics in grazed woodlands. Plant Biology 1: 127-137
187 Prop, J. & J.M. Black. 1998. Food intake, body reserves and reproductive success of barnacle geese Branta leucopsis staging in different habitats. Norsk Polarinst. Skr. 200: 175-193.
172 Pearl, R. 1925. The biology of population growth. Alfred Knopf, New York.
188 Prop, J. & T.Vulink. 1992. Digestion by barnacle geese in the annual cycle: the interplay between retention time and food quality. Funct. Ecol. 6: 180-189.
173 Pen, I. 2000. Reproductive effort in viscous populations. Evolution 54: 293-297.
308
27-01-2006
14:46
Pagina 309
189 Prop, J., Black, J.M. & P. Shimmings. 2003. Travel schedules to the high arctic: barnacle geese trade-off the timing of migration with accumulation of fat deposits. Oikos 103: 403-414.
202 Teunissen,W., Spaans, B. & R.H. Drent 1985. Breeding success in brent in relation to individual feeding opportunities during spring staging in the Wadden Sea. Ardea 73: 109-120.
190 Raveling, D.G. 1979. The annual cycle of body composition of Canada Geese with special reference to control of reproduction. Auk 96: 234-252.
203 Tieleman, B.I. & J.B.Williams. 2002. Effects of food supplementation on behavioral decisions of Hoopoe larks in the Arabian Desert: balancing water, energy and thermoregulation. Animal Behaviour 63: 519529.
191 Riisgard, H.U. & P. Kamermans. 2001. Switching between deposit-and suspension-feeding in coastal zoobenthos. In Reise, K. (ed.). Ecological Comparisons of Sedimentary Shores: 73101. Springer Verlag, Berlin.
204 Tieleman, B.I. & J.E.Williams. 2000. The adjustment of avian metabolic rates and water fluxes to desert environments. Physiol. Biochem. Zool. 73: 461-479.
192 Rubenstein, D.R. & K.A. Hobson. 2004. From birds to butterflies: animal movement patterns and stable isotopes. Trends in Ecology & Evolution 19: 256-263.
205 Tieleman, B.I.,Williams, J.B. & G.H.Visser. 2004. Energy and water budgets of larks in a life history perspective: parental effort varies with aridity. Ecology 85: 1399-1410.
193 Ryden, H. 1989. Lily Pond: four years with a family of beavers. William Morrow and Company, New York.
206 Tieleman, B.I.,Williams, J.B. & M.E. Buschur. 2002. Physiological adjustments to arid and mesic environments in larks (Alaudidae). Physiological and Biochemical Zoology 75: 305-313.
194 Schekkerman, H., Tulp, I., Piersma, T. & G.H. Visser. 2003. Mechanisms promoting higher growth rate in arctic than in temperate shorebirds. Oecologia 134: 332-342.
207 Tinbergen, J.M. & C. Both. 1999. Is clutch size individually optimized? Behav. Ecol. 10: 504-509.
195 Schmidt-Nielsen, K. 2001. Animal physiology: adaptation and environment (5th edition),
208 Tinbergen, J.M. & J.J. Sanz. 2004. Strong evidence for selection for larger brood size in a great tit population. Behav. Ecol. 15: 525533.
Cambridge University Press, Cambridge. 196 Speakman, J.R. 2000. The cost of living: field metabolic rates of small mammals. Adv. Ecol. Res. 30: 177-297.
209 Tinbergen, J.M. & S. Daan. 1990. Family planning in the Great Tit (Parus major): optimal clutch size as integration of parent and offspring fitness. Behaviour 114: 161-190.
197 Stahl,J., Tolsma, P.H., Loonen, M.J.J.E. & R.H. Drent 2001. Subordinates explore but dominants profit: resource competition in high Arctic barnacle goose flocks. Anim. Behav. 61: 257-264.
210 Trivers, R.L. 1972. Parental investment and sexual selection. In Campbell, B. (ed.). Sexual selection and the descent of man: 136-179. Heineman, London.
198 Steeger, C., Esselink, H. & R.C.Ydenberg. 1992. Comparative feeding ecology and reproductive performance of ospreys in different habitats of southeastern British Columbia. Can. J. Zool. 70: 470-475.
211 Van de Kam, J., Ens, B., Piersma, T. & L. Zwarts 2004. Shorebirds, an illustrated behavioural ecology. KNNV Publishers, Utrecht.
199 Stienen, E. 2002. Grote Stern, Sterna sandvicensis. pp. 246-247 in: SOVON Vogelonderzoek Nederland 2002, Atlas van de Nederlandse Broedvogels 1998-2000.– Ned. Fauna 5. Nationaal Natuurhistorisch Museum Naturalis, KNNV Uitgeverij & European Invertebrate Survey-Nederland, Leiden
212 Van de Koppel, J., Herman, P.M.J., Thoolen, P. & C.H.R. Heip. 2001. Do alternate stable states occur in natural ecosystems? Evidence from a tidal flat. Ecology 82: 3449-3461. 213 Van der Graaf, A.J., Bos, D., Loonen, M.J.J.E., Engelmoer, M. & R.H. Drent 2002. Shortterm and long-term facilitation of goose grazing by livestock in the Dutch Wadden Sea area. J. Coastal Conservation 8: 179-188.
200 Stienen, E. 2005. Living with gulls: Trading off food and predation in the Sandwich Tern Sterna sandvicensis. Dissertation, University of Groningen, Groningen.
214 Van der Graaf, A.J., Stahl J. & J.P. Bakker. 2005. Compensatory growth of Festuca rubra after grazing – Can migratory herbivores increase their own harvest during staging? Funct. Ecol. 19.
201 Stienen, E.W.M., van Beers, A., Brenninkmeijer, A., Habraken, J.M.P.M., Raaijmakers, M.H.J.E. & P.G.M. van Tienen. 2000. Reflections of a specialist: patterns in food provisioning and foraging conditions in Sandwich Terns Sterna sandvicensis. Ardea 88: 33-49.
215 Van der Jeugd, H., Olthoff, M. & J. Stahl 2001. Breeding range translates into staging site
309
REFERENCES
*Ontwerp def.
*Ontwerp def.
27-01-2006
14:46
Pagina 310
V227 an Gils, J.A., De Rooij, R.,Van Belle, J.,Van der Meer, J., Dekinga, A. Piersma, T. & R. Drent. 2005b. Digestive bottleneck affects foraging decisions in red knots (Calidris canutus). I. Prey choice. J. Anim. Ecol. 74: 105-119.
choice: Baltic and Arctic Barnacle Geese Branta leucopsis use different habitats at a Dutch Wadden Sea island. Ardea 89: 253265. 216 Van der Jeugd, H.P., Gurtovaya, E., Eichhorn, G., Litvin, K.Ye., Mineyev, O.Y. & M.R. van Eerden. 2003. Breeding barnacle geese in Kolokolkova Bay, Russia: number of breeding pairs, reproductive success and morphology. Polar Biol. 26: 700-706.
228 Van Gils, J.A., Dekinga, A., Spaans, B.,Vahl,W.K. & T. Piersma. 2005c. Digestive bottleneck affects foraging decisions in red knots (Calidris canutus). II. Patch choice and length of working day. J. Anim. Ecol. 74: 120-130.
217 Van der Meer, J. & B.J. Ens. 1997. Models of interference and their consequences for the spatial distribution of ideal and free predators. J. Anim. Ecol. 66: 846-858.
229 Van Marken Lichtenbelt,W.,Wesselingh, R.,Vogel, J. & K. Albers.1993. Energy budgets in free living green iguanas in a seasonal environment. Ecology 74: 1157-1172.
218 Van der Meer, J., Beukema, J.J. & R. Dekker. 2001. Long-term variability in secondary production of an intertidal bivalve population is primarily a matter of recruitment variability. J. Anim. Ecol. 70: 159-169.
230 van Rhijn, J.G. 1985. Black-headed gull or blackheaded girl? On the advantage of concealing sex in gulls and other colonial birds. Neth. J. Zool. 35: 87-102. 231 Van Rhijn, J.G. 1991. The Ruff: individuality in a gregarious wading bird. T. & A.D. Poyser, London.
219 Van der Wal, R., Kunst, P. & R. Drent. 1998. Interactions between hare and brent goose in a salt marsh system: Evidence for food competition? Oecologia 117: 227-234.
232 Van Rhijn, J.G. & A.G.G. Groothuis. 1987. On the mechanism of mate selection in Blackheaded Gulls. Behaviour 100: 134-169.
220 Van der Wal, R.,Van Lieshout, S., Bos, D. & R.H. Drent. 2000. Are spring staging brent geese evicted by vegetation succession? Ecography 23: 60-69.
233 Van Rhijn, J.G. & R.Vodegel. 1980. Being honest about one’s intentions, an evolutionary stable strategy for animal conflicts. J.Theor. Biol. 85: 623-641.
221 Van der Wal, R.,Van Wijnen, H.,Van Wieren, S., Beucher, O. & D. Bos. 2000. On facilitation between herbivores: how brent geese profit from brown hares. Ecology 81: 969980.
234 Veen, J. 1977. Functional and causal aspects of nest distribution in colonies of the Sandwich Tern (Sterna s. sandvicensis Lath.). Behaviour Suppl. 20: 1-193. 235 Veen, J. & T. Piersma. 1986. Causation and function of different vocal reactions of Little Gulls Larus minutus to intruders near the nest. Behaviour 96: 241-264.
222 Van Eerden, M.R. 1984. Waterfowl movements in relation to food stocks. In: Evans, P.R., Goss-Custard, J.D. & W.G. Hale (eds.). Coastal waders and wildfowl in winter: 84-100. Cambridge University Press, Cambridge.
236 Veen, T., Borge, T., Griffith, S.C., Sætre, G.P., Bures, S., Gustasson, L. & B.C. Sheldon. 2001. Hybridization and adaptive mate choice in flycatchers. Nature 411: 45-50.
223 Van Eerden, M.R. 1998. Patchwork: Patch use, habitat exploitation and carrying capacity for water birds in Dutch freshwater wetlands. Van Zee tot Land (Lelystad) 65: 1-447.
237 Vera, F.W.M. 2000. Grazing Ecology and Forest History. CABI, Wallingford.
224 Van Eerden, M.R., Drent, R.H., Stahl, J. & J.P. Bakker. 2005. Connecting seas: western Palaearctic continental flyway for water birds in the perspective of changing land use and climate. Global Change Biol. 11: 894908.
238 Verhulst, S. & J.M. Tinbergen. 1991. Experimental evidence for a causal relationship between timing and success of reproduction in the Great Tit Parus m. major. J.Anim. Ecol. 69: 269282. 239 Verhulst, S., Oosterbeek, K., Rutten, A.L. & B.J. Ens. 2004. Shellfish fishery severely reduces condition and survival of oystercatchers despite creation of Large Marine Protected Areas. Ecology & Society 9: 17.
225 Van Eerden, M.R., Zijlstra, M., van Roomen, M. & A. Timmerman. 1996. The response of Anatidae to changes in agricultural practice: long-term shifts in the carrying capacity of wintering waterfowl. Gibier Faune Sauvage 13: 681-706.
240 Visser, M.E., van Noordwijk, A.J., Tinbergen, J.M. & C.M. Lessells. 1998. Warmer springs lead to mis-timed reproduction in great tits (Parus major). Proc. Roy. Soc. (Lond.) B 265: 1867-1870
226 Van Gils, J.A., Battley, P.F., Piersma, T. & R. Drent. 2005a. Reinterpretation of gizzard sizes of red knots world-wide emphasises overriding importance of prey quality at migratory stopover sites. Proc. R. Soc. London B (in press).
310
*Ontwerp def.
27-01-2006
14:46
Pagina 311
255 Witte, F., Goldschmidt, T.,Wanink, J., van Oijen, M., Goudswaard, K.,Witte-Maas, E. & E. Bouton. 1992. The destruction of an endemic species flock: quantitative data on the decline of the haplochromine species from the Mwanza Gulf (Lake Victoria). Env. Biol. Fish. 34: 1-28.
241 Vulink, J.T. 2001. Hungry Herds, management of temperate lowland wetlands by grazing. Van Zee tot Land (Lelystad) 66: 1-394. 242 Wanink, J. & L. Zwarts. 1985. Does an optimally foraging oystercatcher obey the functional response? Oecologia 67: 98-106. 243 Wanink, J.H. 1996. Foraging locations of kingfishers and cormorants at Lake Victoria depend on the distribution of harvestable prey. Afr. J. Ecol. 34: 90-93.
256 Ydenberg, R.C. 1998. Behavioral decisions about foraging and predator avoidance. In: R. Dukas (ed.). Cognitive Ecology: 343-378. The University of Chicago Press, Chicago.
244 Wanink, J.H. 1998. Were the effects of Nile perch introduction on Lake Victoria’s birds predictable? In Goss-Custard, J.D. et al. (eds.). Effect of habitat loss and change on waterbirds: 131-137. HM Stationary Office, London.
257 Zippelius, H-M. 1992. Die vermessene Theorie: eine kritische Auseinandersetzung mit der Instinkttheorie von Konrad Lorenz und verhaltenskundlicher Forschungspraxis. Friedr. Vieweg & Sohn, Braunschweig, p.1-295 (see pp. 141168).
245 Wanink, J.H. & F.Witte. 2000. The use of perturbation as a natural experiment: effects of predator introduction on the community structure of zooplanktivorous fish in Lake Victoria. Adv. Ecol. Res. 31: 553-570.
258 Zwarts, L. 1986. Burying depth of the benthic bivalve Scrobicularia plana (da Costa) in relation to siphon-cropping. J. Exp. Mar. Biol. Ecol. 101: 25-39.
246 Wanink, J.H. & P.C. Goudswaard. 2000.The impact of Lake Victoria’s lakefly abundance on Palearctic passerines. Ostrich 71: 194-197.
259 Zwarts, L. & J.H.Wanink. 1984. How oystercatchers and curlews successively deplete clams. In Evans, P.R. et al. (eds.). Coastal waders and wildfowl in winter: 69-83. Cambridge University Press, Cambridge.
247 Westerterp, K.R. 2001. Energy and water balance at high altitude. News Physiol. Sci. 15: 134137.
260 Zwarts, L. & J.H.Wanink. 1989. Siphon size and burying depth in deposit- and suspension feeding benthic bivalves. Mar. Biol. 100: 227-240.
248 Westerterp, K.R. 2001. Limits to sustainable human metabolic rate. J. Exp. Biol. 204: 3183-3187. 249 Westerterp, K.R., Kayser, B., Brouns, F., Herry, J.P. & W.H.M. Saris. 1992. Energy expenditure climbing Mt Everest. J. Appl. Physiol. 73: 1815-1819.
261 Zwarts, L., Cayford, J.T., Hulscher, J.B., Kersten, M., Meire, P.M. & P. Triplet. 1996. Prey size selection and intake rate. In GossCustard, J.D. (ed.). The oystercatcher: 30-55. Oxford University Press, Oxford.
250 Wiersma, P. & T. Piersma. 1994. Effects of microhabitat, flocking, climate and migratory goal on energy expenditure in the annual cycle of red knots. Condor 96: 257-279.
262 Zwarts, L.,Wanink, J.H. & B.J. Ens. 1996. Predicting seasonal and annual fluctuations in the local exploitation of different prey by oystercatchers Haematopus ostralegus: A ten-year study in the Wadden Sea. Ardea 84: 401-440.
251 Wikelski, M., Tarlow, E.M., Raim, A., Diehl, R.H., Larkin, R.P. & G.H.Visser. 2003. Cost of migration in free-flying songbirds. Nature 423: 704. 252 Williams, J.B., Tieleman, B.I. & M. Shobrak. 1999. Lizard burrows provide thermal refugia for larks in the Arabian desert. Condor 101: 714-717.
254 Witte, F., Goldschmidt, T. & J.H.Wanink. 1995. Dynamics of the haplochromine cichlid fauna and other ecological changes in the Mwanza Gulf of Lake Victoria. In Pitcher, T.J. & P.J.B. Hart (eds.). The impact of species changes in African lakes: 83-110. Chapman & Hall, London.
311
REFERENCES
253 Wilson, R.P., Ducamp, J.J., Rees, G., Culik, B.M. & K. Niekamp. 1992. Estimation of location: global coverage using light intensity. In: Priede I.M. & S.M. Swift (eds.). Wildlife telemetry: remote monitoring and tracking of animals: 131-134. Horward, Chichester.
