A Mixed Modeling Approach to Predict the Effect of Environmental Modification on Species Distributions
Cozzoli, F. ; Eelkema, M. ; Bouma, T.J. ; Ysebaert, T. ; Escaravage, V. ; Herman, P.M.J. - \ 2014
PLoS ONE 9 (2014)2. - ISSN 1932-6203
cockles cerastoderma-edule - natural animal assemblages - quantile regression - lanice-conchilega - body-size - ecosystem engineers - sediment transport - hydrobia-ulvae - abundance - oosterschelde
Human infrastructures can modify ecosystems, thereby affecting the occurrence and spatial distribution of organisms, as well as ecosystem functionality. Sustainable development requires the ability to predict responses of species to anthropogenic pressures. We investigated the large scale, long term effect of important human alterations of benthic habitats with an integrated approach combining engineering and ecological modelling. We focused our analysis on the Oosterschelde basin (The Netherlands), which was partially embanked by a storm surge barrier (Oosterscheldekering, 1986). We made use of 1) a prognostic (numerical) environmental (hydrodynamic) model and 2) a novel application of quantile regression to Species Distribution Modeling (SDM) to simulate both the realized and potential (habitat suitability) abundance of four macrozoobenthic species: Scoloplos armiger, Peringia ulvae, Cerastoderma edule and Lanice conchilega. The analysis shows that part of the fluctuations in macrozoobenthic biomass stocks during the last decades is related to the effect of the coastal defense infrastructures on the basin morphology and hydrodynamics. The methodological framework we propose is particularly suitable for the analysis of large abundance datasets combined with high-resolution environmental data. Our analysis provides useful information on future changes in ecosystem functionality induced by human activities.
Causes and effects of a highly successful marine invasion: Case-study of the introduced Pacific oyster Crassostrea gigas in continental NW European estuaries
Troost, K. - \ 2010
Journal of Sea Research 64 (2010)3. - ISSN 1385-1101 - p. 145 - 165.
mussel mytilus-edulis - suspension-feeding bivalves - cockles cerastoderma-edule - enemy release hypothesis - northern wadden sea - long-term changes - biological invasions - japanese oyster - ecosystem engineers - filtration-rate
Since the 1960's, the Pacific oyster Crassostrea gigas has been introduced for mariculture at several locations within NW Europe. The oyster established itself everywhere and expanded rapidly throughout the receiving ecosystems, forming extensive and dense reef structures. It became clear that the Pacific oyster induced major changes in NW European estuaries. This paper reviews the causes of the Pacific oyster's remarkably successful establishment and spread in The Netherlands and neighbouring countries, and includes a comprehensive review of consequences for the receiving communities. Ecosystem engineering by C. gigas and a relative lack of natural enemies in receiving ecosystems are identified as the most important characteristics facilitating the invader's successful establishment and expansion. The Pacific oyster's large filtration capacity and eco-engineering characteristics induced many changes in receiving ecosystems. Different estuaries are affected differently; in the Dutch Oosterschelde estuary expanding stocks saturate the carrying capacity whereas in the Wadden Sea no such problems exist. In general, the Pacific oyster seems to fit well within continental NW European estuarine ecosystems and there is no evidence that the invader outcompetes native bivalves. C. gigas induces changes in plankton composition, habitat heterogeneity and biodiversity, carrying capacity, food webs and parasite life cycles. The case of the Pacific oyster in NW European estuaries is only one example in an increasing series of biological invasions mediated by human activities. This case-study will contribute to further elucidating general mechanisms in marine invasions; invasions that sometimes appear a threat, but can also contribute to ecological complexity.
Optimal foraging on perilous prey: risk of bill damage reduces optimal prey size in oystercatchers
Rutten, A.L. ; Oosterbeek, K.H. ; Ens, B.J. ; Verhulst, S. - \ 2006
Behavioral Ecology 17 (2006)2. - ISSN 1045-2249 - p. 297 - 302.
cockles cerastoderma-edule - haematopus-ostralegus - mytilus-edulis - seasonal-changes - selection - energy - interference - predation - strength - behavior
Intake rate maximization alone is not always sufficient in explaining prey size selection in predators. For example, bivalve-feeding oystercatchers regularly select smaller prey than expected if they aimed to maximize their intake rate. It has been proposed that to these birds large prey are "risky," in the sense that birds may damage their bills when feeding on large bivalves. Large bivalves yield more energy, but according to this hypothesis this is achieved at the expense of energy yield in the long term when (1) the risk of bill damage increases with prey size and (2) foraging with a damaged bill is less effective. In accordance with this hypothesis, we show that captive oystercatchers feeding on large cockles experienced a high probability of bill tip damage, while bill damage was absent when cockles were small. Moreover, among free-living oystercatchers the prevalence of bill damage was correlated with mean cockle size near the capture site, and the data on captive birds fit in this pattern. Food intake of captive oystercatchers feeding exclusively on cockles was reduced by 23% after bill damage, and free-living birds with damaged bills had 14 g lower mass. Because lower body mass was associated with higher mortality probability, these results indicate long-term costs associated with feeding on large cockles. We conclude that the risk of bill damage can potentially explain why oystercatchers avoid large bivalves and that oystercatchers may maximize long-term intake rate by selecting prey sizes that are "suboptimal" from a short-term rate-maximizing point of view.
Intake rates and the functional response in shorebirds (Charadriiformes) eating macro-invertebrates
Goss-Custard, J.D. ; West, A.D. ; Yates, M.G. ; Caldow, R.W.G. ; Stillman, R.A. ; Bardsley, L. ; Castilla, J. ; Castro, M. ; Dierschke, V. ; Durell, S.E.A.L.V. ; Eichhorn, G. ; Ens, B.J. ; Exo, K.M. ; Udayangani-Fernando, P.U. ; Ferns, P.N. ; Hockey, P.A.R. ; Gill, J.A. ; Johnstone, I. ; Kalejta-Summers, B. ; Masero, J.A. ; Moreira, F. ; Nagarajan, R.V. ; Owens, I.P.F. ; Pacheco, C. ; Perez-Hurtado, A. ; Rogers, D. ; Scheiffarth, G. ; Sitters, H. ; Sutherland, W.J. ; Triplet, P. ; Worrall, D.H. ; Zharikov, Y. ; Zwarts, L. ; Pettifor, R.A. - \ 2006
Biological Reviews 81 (2006)4. - ISSN 1464-7931 - p. 501 - 529.
oystercatchers haematopus-ostralegus - bivalve macoma-balthica - mussels mytilus-edulis - knots calidris-canutus - tringa-totanus l - plovers pluvialis-squatarola - whimbrels numenius-phaeopus - ragworm nereis-diversicolor - cockles cerastoderma-edule - wading bir
As field determinations take much effort, it would be useful to be able to predict easily the coefficients describing the functional response of free-living predators, the function relating food intake rate to the abundance of food organisms in the environment. As a means easily to parameterise an individual-based model of shorebird Charadriiformes populations, we attempted this for shorebirds eating macro-invertebrates. Intake rate is measured as the ash-free dry mass (AFDM) per second of active foraging; i.e. excluding time spent on digestive pauses and other activities, such as preening. The present and previous studies show that the general shape of the functional response in shorebirds eating approximately the same size of prey across the full range of prey density is a decelerating rise to a plateau, thus approximating the Holling type II ('disc equation') formulation. But field studies confirmed that the asymptote was not set by handling time, as assumed by the disc equation, because only about half the foraging time was spent in successfully or unsuccessfully attacking and handling prey, the rest being devoted to searching. A review of 30 functional responses showed that intake rate in free-living shorebirds varied independently of prey density over a wide range, with the asymptote being reached at very low prey densities (