The scale of landscape fragmentation affects herbivore response to vegetation heterogeneity

Abstract Using alternating bands of weeds and broccoli I experimentally manipulated vegetation composition and the spatial scale at which the landscape was fragmented in a factorial design. This experimental approach allowed me to distinguish the effect of spatial scale from that of simple crop heterogeneity on crop herbivores. The importance of scale depended on which insect species were examined. Cabbage aphids (Brevicoryne brassicae) were influenced by vegetation composition at all tested scales of fragmentation; cabbage butterflies (Pieris rapae) were not affected by scale or by composition and flea beetles (Phyllotreta cruciferae) revealed a striking dependence on scale of fragmentation as well as an interaction between scale and composition. This approach shows the importance of dissecting out the effects of scale from other aspects of landscape manipulation, and emphasizes the challenge of developing a theory that will enable prediction of species–specific responses to scale.

[1]  David A. Andow,et al.  The extent of monoculture and its effects on insect pest populations with particular reference to wheat and cotton , 1983 .

[2]  W. S. Lawrence,et al.  Chrysomelid Beetle Movements in Relation to Host‐Plant Size and Surrounding Non‐Host Vegetation , 1989 .

[3]  L. Fahrig,et al.  Habitat Patch Connectivity and Population Survival , 1985 .

[4]  J. B. Kring.  Flight Behavior of Aphids , 1972 .

[5]  C. E. Bach,et al.  Effects of Host Plant Patch Size on Herbivore Density: Patterns , 1988 .

[6]  R. E. Jones,et al.  The Ecology of pests: Some Australian case histories , 1981 .

[7]  Marc Mangel,et al.  Spatial patterning in resource exploitation and conservation , 1994 .

[8]  E. Bernays,et al.  Host-Plant Selection by Phytophagous Insects , 1994, Contemporary Topics in Entomology.

[9]  T. Tscharntke,et al.  Habitat Fragmentation, Species Loss, and Biological Control , 1994, Science.

[10]  S. Levin.  Patchiness in marine and terrestrial systems: from individuals to populations , 1994 .

[11]  Catherine E. Bach,et al.  Effects of Plant Density and Diversity on the Population Dynamics of a Specialist Herbivore, the Striped Cucumber Beetle, Acalymma Vittata (Fab) , 1980 .

[12]  S. Levin.  THE PROBLEM OF PATTERN AND SCALE IN ECOLOGY , 1992 .

[13]  D. Pilson.  TWO HERBIVORES AND CONSTRAINTS ON SELECTION FOR RESISTANCE IN BRASSICA RAPA , 1996, Evolution; international journal of organic evolution.

[14]  Peter Kareiva,et al.  THE SEARCH FOR RESOURCES BY CABBAGE BUTTERFLIES (PIERIS RAPAE): ECOLOGICAL CONSEQUENCES AND ADAPTIVE SIGNIFICANCE OF MARKOVIAN MOVEMENTS IN A PATCHY ENVIRONMENT' , 1984 .

[15]  M. Llewellyn.  The biology of aphids , 1984 .

[16]  J. Wiens.  Spatial Scaling in Ecology , 1989 .

[17]  Rhondda Jones,et al.  Long-distance movement of Pieris rapae. , 1980 .

[18]  D. Letourneau.  ASSOCIATIONAL SUSCEPTIBILITY: EFFECTS OF CROPPING PATTERN AND FERTILIZER ON MALAWIAN BEAN FLY LEVELS' , 1995 .

[19]  D. Landis,et al.  Effect of Landscape Structure on Parasitoid Diversity and Parasitism in Agroecosystems , 1996 .

[20]  Lenore Fahrig,et al.  Effect of Spatial Arrangement of Habitat Patches on Local Population Size , 1988 .

[21]  J. Dempster.  Some Effects of Weed Control on the Numbers of the Small Cabbage White (Pieris rapae L.) on Brussels Sprouts , 1969 .

[22]  D. Andow,et al.  Agroecosystem Diversity and Pest Control: Data, Tentative Conclusions, and New Research Directions , 1983 .

[23]  P. Kareiva,et al.  Habitat fragmentation and the stability of predator–prey interactions , 1987, Nature.

[24]  R. Gardner,et al.  Quantitative methods in landscape ecology: an introduction , 1991 .

[25]  W. J. Cromartie.  The Effect of Stand Size and Vegetational Background on the Colonization of Cruciferous Plants by Herbivorous Insects , 1975 .

[26]  T. O. Crist,et al.  Critical Thresholds in Species' Responses to Landscape Structure , 1995 .

[27]  D. Andow.  Vegetational Diversity and Arthropod Population Response , 1991 .

[28]  Marc Mangel,et al.  Individuals on the landscape : behavior can mitigate landscape differences among habitats , 1997 .

[29]  Peter Kareiva,et al.  Spatial scale mediates the influence of habitat fragmentation on dispersal success: Implications for conservation , 1992 .

[30]  Michael J. Costello.  Spectral reflectance from a broccoli crop with vegetation or soil as background: influence on immigration by Brevicoryne brassicae and Myzus persicae , 1995 .

[31]  D. Andow.  Population Dynamics of an Insect Herbivore in Simple and Diverse Habitats , 1990 .

[32]  R. Plant,et al.  Role of Movement in the Response of Natural Enemies to Agroecosystem Diversification: A Theoretical Evaluation , 1993 .

[33]  P. Kareiva,et al.  Finding and Losing Host Plants by Phyllotreta: Patch Size and Surrounding Habitat , 1985 .

[34]  D. Andow,et al.  Flea beetle movement in a broccoli monoculture and diculture , 1988 .

[35]  W. C. Leggett,et al.  The importance of scale to predator-prey spatial correlations: an example of Atlantic fishes , 1990 .

[36]  D. Letourneau.  The Enemies Hypothesis: Tritrophic Interactions and Vegetational Diversity in Tropical Agroecosystems. , 1987, Ecology.

[37]  P. Kareiva,et al.  Experimental and Mathematical Analyses of Herbivore Movement: Quantifying the Influence of Plant Spacing and Quality on Foraging Discrimination , 1982 .

[38]  D. Mccauley.  THE EFFECT OF HOST PLANT PATCH SIZE VARIATION ON THE POPULATION STRUCTURE OF A SPECIALIST HERBIVORE INSECT, TETRAOPES TETRAOPHTHALMUS , 1991, Evolution; international journal of organic evolution.

[39]  R. B. Root.  Organization of a Plant-Arthropod Association in Simple and Diverse Habitats: The Fauna of Collards (Brassica Oleracea) , 1973 .

[40]  I. Perfecto,et al.  Vegetational Diversity, Ants (Hymenoptera: Formicidae), and Herbivorous Pests in a Neotropical Agroecosystem , 1992 .

[41]  P. Kareiva,et al.  The influence of food plant dispersion on caterpillar searching success , 1985 .

[42]  S. L. Lima,et al.  Towards a behavioral ecology of ecological landscapes. , 1996, Trends in ecology & evolution.

[43]  L. Fahrig,et al.  Interpatch dispersal of the cabbage butterfly , 1987 .

[44]  D. Murphy.  Conservation and Confusion: Wrong Species, Wrong Scale, Wrong Conclusions , 1989 .

[45]  Alan Molumby.  Dynamics of parasitism in the organ‐pipe wasp, Trypoxylon politurn: effects of spatial scale on parasitoid functional response , 1995 .

[46]  C. Hodgson.  Dispersal of apterous aphids (Homoptera: Aphididae) from their host plant and its significance , 1991 .

[47]  D. N. Byrne,et al.  The effects of crop diversification on herbivorous insects: a meta‐analysis approach , 1994 .