Ecology, 86(3), 2005, pp. 587±593 ᭧ 2005 by the Ecological Society of America

FIRE GENERATES SPATIAL GRADIENTS IN HERBIVORY: AN EXAMPLE FROM A FLORIDA SANDHILL ECOSYSTEM

TIFFANY M. KNIGHT1 AND ROBERT D. HOLT University of Florida, Department of Zoology, 223 Bartram Hall, P.O. Box 118525, Gainesville, Florida 32611-8525 USA

Abstract. Disturbance can directly affect the interactions among species at different trophic levels. Because disturbances are typically localized, and many consumers are con- strained in their mobility, disturbances can generate spatial variability in trophic interac- tions. Here, we consider how ®re alters plant±insect interactions in a longleaf pine ecosystem in central Florida, USA. We hypothesized that ®re in the short term would directly depress herbivore abundance, and that the rate of re-colonization by herbivores would depend upon distance from the edge of the recently burned area. Thus, ®re should generate spatially varying herbivory. Orthopterans are dominant insect consumers in our system, and many species are ¯ightless, either as juveniles or adults; these species are particularly likely to show constrained post-®re mobility. We quanti®ed insect abundance and herbivory levels on eight common understory plants in the edge and interior of three recently burned sites. As predicted, insect abundance at the edge of burned areas was much higher than in the interior. In addition, all plant species experienced at least twice the level of herbivory in the edge than in the interior of burned sites. This demonstrates that disturbance can create strong spatial variation in the magnitude of trophic interactions. We suggest that larger burns may aid in plant management by reducing herbivory, whereas the presence of un- burned refugia may be critical to insect conservation. Key words: disturbance ecology; ®re; Florida (USA) pine ecosystem; herbivory; Orthoptera;

prescribed burn; sandhill ecosystem; spatial gradient; trophic interactions. Reports

INTRODUCTION bance, whereas gaps created by multiple treefalls pro- vide adequate light to allow recruitment of new indi- Disturbances in¯uence the structure and function of viduals from seed (e.g., Lorimer 1989). Here we sug- many communities (Petraitis et al. 1989, Shea et al. gest that large disturbances may also allow for edge 2004). Indeed, disturbances are often de®ned as dis- effects, since displaced organisms recolonize the edge crete events that disrupt ecosystem, community, or ®rst, and then the interior. For example, if predators population structure and change resource, substrate are displaced by disturbance and then recolonize, prey availability, or the physical environment (sensu White will experience higher levels of predation near the edge and Pickett 1985). Because disturbances are almost al- than near the interior of the disturbed site. This would ways spatially localized in extent and intensity (Turner create spatial heterogeneity in trophic interactions, the et al. 2001), they create spatial structure in a landscape; duration of which will depend on both the size of the areas disturbed by some event are typically adjacent to disturbance and the dispersal ability of the displaced areas less disturbed by that same event. Moreover, dis- species. turbances may differentially affect the abundance of In this study we examine how ®re in¯uences the species in different trophic levels (Power et al. 1996, spatial pattern of trophic interactions between herbiv- Wootton 1998, Moore et al. 2004), and can therefore orous insects and plants in a longleaf pine ecosystem, alter the intensity of trophic interactions and alter spa- which was historically maintained by periodic ®res tial patterns of species diversity and composition (Platt et al. 1988). Effects of ®re on plant diversity and through disturbance-induced edge-effects (Fagan et al. community composition are well documented, as are 1999, Cantrell et al. 2001). the effects of temporal burn patterns (e.g., Menges and Disturbances that are large in spatial extent may have Hawkes 1998). However, less is known about how ®re qualitatively different effects on species abundances in¯uences other trophic levels, such as herbivorous in- than smaller disturbances (Romme et al. 1998). For sects (Swengel 2001). Even less is known about how example, gaps created by a single treefall are generally trophic interactions vary spatially within burned sites ®lled by understory trees present before the distur- (but see Vickery 2002). Fire may directly and indirectly affect the abundance Manuscript received 2 July 2004; revised 19 August 2004; and diversity of herbivorous insects (Swengel 2001). accepted 27 August 2004. Corresponding Editor: D. P. C. Peters. 1 Present address: Washington University, Department of In the short term, ®re negatively affects insect numbers; Biology, Campus Box 1137, Saint Louis, Missouri 63130 many are killed by ®re, or die of starvation before their USA. E-mail: [email protected] host plants reemerge or germinate post-®re. Less mo- 587 Reports eeoeet nteitniyo herbivory. of spatial intensity to spatial the lead in this should heterogeneity abundance plants, herbivore on in damage pattern signi®cant herbivores these in¯ict the If area. in can burned lowest recently and the of refugia interior unburned to near a abundant adjacent after most edges be shortly should area insects burned herbivorous the ®re, in area Therefore, that 2001). burned hypothesize Swengel we before large 1996, years Nichols a to and recolonize (Pippin months completely take can may they ¯ight species at Insect 2003). adept Panzer less 2000, al. et (Harper areas (refugia) unburned individuals adjacent of from survival recolonization situ by in and by in ®re a pupae after populations recover and Insect can eggs vulnerable. particularly (e.g., are stages and soil) the life [Bock and grasshoppers 1991]) ¯ightless Bock (e.g., species bile 588 esnbr.Poocei:SehnCae.(o right) (Top Coates. Stephen credit: Photo burn. season rsre hr h niec fhrioyi ih ht rdt .Knight. T. credit: Photo high. is herbivory of incidence the where Preserve, P rsreta s¯gtestruhu t ie ht rdt o hs.(otmlf)Typical left) (Bottom Chase. Jon credit: Photo life. its throughout ¯ightless is that Preserve LATE nteitro farcnl undsnhl tteOda rsre hr h niec fhrioyi o.Poocredit: Photo low. is herbivory of incidence the where Preserve, Ordway the at Typical sandhill right) burned (Bottom recently Knight. a T. of interior the in .(o et adilEoytma h rwyPeev.Ti htgahwstknafwmnh fe growing a after months few a taken was photograph This Preserve. Ordway the at Ecosystem Sandhill left) (Top 1. ehoi virginiana Tephrosia IFN .KIH N OETD HOLT D. ROBERT AND KNIGHT M. TIFFANY niiuli h deo eetybre adila h Ordway the at sandhill burned recently a of edge the in individual eaolsrotundipennis, Melanoplus tr fti omnt sdmntdb ogefpine longleaf by dominated ( is community this of over- The story 1). with Plate see hilltops 1990; (Myers on sands well-drained occurs which Florida, North-Central tts hl oa only today while States, oiae ywrgas( wiregrass by dominated iu palustris Pinus aks19) hn®ei upesd h system (Myers the and community suppressed, forest Menges hardwood is a 1998, toward ®re succeeds Frost When 1998). 1990, Hawkes is (Myers sandhills in years frequency 1±10 ®re natural The 1989). (Noss it fprnilhrs adilvgtto necov- once vegetation ered Sandhill herbs. perennial of riety lrd rosemary, Florida ogefpn,tre a ( oak turkey pine, longleaf u td ie eei h adileoytmof ecosystem sandhill the in were sites study Our Ͼ 8mlinhcae ntesuhatUnited southeast the in hectares million 28 .Gon oe stpclydense, typically is cover Ground ). eail ericoides Ceratiola omngasopra h Ordway the at grasshopper common a M ETHODS uru laevis Quercus Ͻ ehoi virginiana Tephrosia rsiastricta Aristida ilo etrsremain hectares million 2 clg,Vl 6 o 3 No. 86, Vol. Ecology, ,adawd va- wide a and ), ,srb (e.g., shrubs ), ,juvenile ), individual March 2005 FIRE GENERATES SPATIAL MOSAICS OF HERBIVORY 589

1990), and thus prescribed burning is a critical tool for were separated by at least 5 m (bare areas of ground managing these endangered habitats (Platt et al. 1988). were not sampled). We sampled quadrats by gently stir- We chose three sites that had large prescribed ®res ring the area with a 1.5-m stick and counting the num- in early spring 2003: two at the Katharine Ordway Pre- ber of insects of each type that emerged. This method serve-Swisher Memorial Sanctuary (University of is particularly useful for sampling grasshopper density Florida; Melrose, Florida, USA) and the third at Gold- (Onsager and Henry 1977). Second, two sweep samples head Branch State Park (Keystone Heights, Florida, were taken at each site and location to improve sam- USA; 15 km from Ordway). At the Ordway sites, ®res pling of less mobile insects (e.g., larval lepidopterans), occurred on 15 February (site 1) and 26 March (site and to supplement our jumping-insect samples. Sweeps 2); each covered 1.9 km2 and were separated by 300 were separated by at least 10 m, but were within 20 m m. One km2 of the third site was burned on 13 February. of the quadrats. Each sweep sample consisted of 10 Prior to 2003, it had been Ͼ10 years since these sites full sweeps, each over a separate 1-m2 area of vegetated had been burned. Understory plants appeared 2±3 ground, using a 38-cm-diameter sweep net. All insects weeks after the ®re at all sites. All ®res were low in were identi®ed into broad taxonomic units (at least to intensity (did not kill canopy or understory trees) and the family level), and all orthopterans were identi®ed were separated from unburned areas by narrow dirt to species using illustrated ®eld guides (Capinera et al. roads. Fires were ignited using backing and strip-head 2001). techniques and were spread by south-southwest winds. While we hypothesize that post-®re spatial distri- The north lines were blackened ®rst with a back ®re butions of herbivorous insects are caused by dispersal (9 m ¯ame lengths), and then burned with multiple limitation, we cannot rule out other hypotheses that ¯ank ®res that traveled from north to south through the may generate the predicted spatial pattern, such as management units (¯ames lengths ranged from 0.5 to greater insect predation in burned interior or attraction 2 m). These ®res left little understory unburned (low of insects to edges. However, the small dirt roads that level of patchiness within each burned site). de®ne the burned sites should have minimal effects on At each site, one edge was chosen for censuses. The the spatial distribution of predatory species (e.g., birds, chosen edge was adjacent to areas not burned within lizards) at these sites. It did seem plausible that insect the past two years and had all eight of our focal plant abundance could be in¯uenced by edges in general. To Reports species at suf®cient densities for sampling. At each site, examine the potential of a generic edge effect, we sam- we chose three sampling locations at different distances pled herbivorous insects (as above) at 100-m intervals into the burn (hereafter ``location''): (1) 10 m just out- from the edge into the burned (six locations: 0±500 m) side the burn (``unburned edge''), (2) 10 m just inside and adjacent unburned areas (four locations: 0±300 m) the burn (``burned edge''), and (3) 500 m inside the at Ordway site 1 on 29 March 2003. burn (``burned interior''). At each location and site we At each site and location, we estimated the amount sampled herbivorous insect diversity and abundance. of foliar herbivory on eight common sandhill plant spe- In two locations (burned edge and burned interior) we cies, spanning a wide variety of life-forms and plant also estimated insect herbivory. Plants in these loca- families: tree seedlings of Diospyros virginiana (Eben- tions presumably experienced the same intensity of ®re aceae, common persimmon) and Quercus laevis (Fa- and post-®re soil nutrient conditions, and occurred at gaceae, turkey oak); the shrubs Asimina incarna (An- similar densities. Therefore, differences in herbivory nonaceae, ¯ag paw paw) and Licania michauxii (Chry- levels should be due to differences in the abundances soblanaceae, gopher apple); and the perennial herbs of herbivores at these locations. We did not sample Croton argyranthemus (Euphorbiaceae, silver croton), herbivory in the unburned edge, because such a com- Eriogonum tomentosum (Polygonaceae, wild buck- parison would provide limited information. Differences wheat), Rhynchosia reniformis (Fabaceae, dollar in herbivory between burned and unburned sites could weed), and Tephrosia virginiana (Fabaceae, goat's be due to differences in the abundances of herbivores, rue). There were no signi®cant differences in plant den- the nutritional quality of the leaves, or the density of sity or individual size between the burned edge and the focal plant species. At each site and location, we interior locations for these species (T. M. Knight and sampled insects and plant damage twiceÐduring the R. D. Holt, unpublished data). At each location and peak of the growing season (17±30 May 2003), and site, we censused plant damage on 10 individuals per near the end (16±19 August 2003). By sampling twice species. Some species are capable of extensive clonal we could assess whether any spatial patterns in her- growth; for these, measurements were taken on indi- bivore abundance and plant damage occurred and vidual ramets. For both clonal and nonclonal species, whether they attenuated throughout the season. we censused individuals separated by at least 5 m to Insects were sampled in two ways: quadrats and reduce the likelihood of spatial autocorrelation in her- sweep netting. All sampling was conducted between bivory. For each individual or ramet, the percentage of 09:00 and 11:00 hours, during peak insect activity leaf tissue leaf lost to herbivores was visually estimated times. First, two parallel rows of 10 0.1-m2 quadrats on a haphazardly chosen sample of leaves for each plant were laid out, separated by 10 m; within rows, quadrats (at least 30% of the total number of leaves present were Reports P ϭ ϫ ϭ mining. leaf categories, and broad chewing two into leaf damage of type cat- the should We egorized locations. which among same bias damage, systematic the any plant eliminate methods, all destructive estimated more individual other pre- than less be cise may estimates visual Although measured). 590 ebvru net b ims)a u td sites, study our at biomass) comprising of (by group abundant insects most herbivorous the far by were grasshoppers) error. II type a of risk the in increasing replicate necessarily low, was separate replication our a therefore and was study, this burn prescribed time each Each appropri- in ate. not sampled were Be- analyses not 100%. repeated-measures were period, and plants 0 same her- between the of in constrained cause percentage skews is the any that data fact for bivory the correct to to due damage ANOVA distribution to arcsine-transformed the as prior We served values replication. value this of location and unit averaged, each were at time damage and in- of their or Measurements August) determine teraction. (May, time to interior), burned ANOVA edge, (burned location used with varied damage we herbivore whether species, For differences. plant pairwise each detect to we HSD effect, Tukey's location used signi®cant a Following analyses. prior to transformed location. log were each values abundance at variables, insect ®xed and quadrats considered were and time and nets location Both sweep orthoptera all of sum in the seen is their burned abundance or Insect August) edge, (May, interaction. time (unburned interior), burned location and edge, with varied dance ainefc a u olwrdniyo orthopterans lo- HSD; of (Tukey's interior density signi®cant burned lower the the to in ®res), due was the effect after cation weeks (7±13 May bevdcnuigalo h td ln pce ex- was species herbivores plant study of the cept group of all this consuming Further, observed 1). Plate (see fet(NV;df (ANOVA; effect eas(efhpesadahd)adlra Lepidop- comprised caterpillars) larval butter¯y and and (moth aphids) terans Homop- and (beetles), (leaf-hoppers Coleopterans terans including insects, of otebre n nundegs hc eenot were HSD; (Tukey's which other edges, each unburned from different and signi®cantly burned the to odce nti group. this be on could conducted statistics meaningful patterns because spatial orthopterans, on In in focus insects. we paper, herbivorous this of of remainder biomass the overall the of each Ͼ rhpeaso h aiisArdde(short-horned Acrididae families the of Orthopterans abun- insect whether determine to ANOVA used We .7)o lg rhpea bnac Fg A.In 1A). (Fig. abundance orthopteran [log] on 0.076) oainitrcin(NV;df (ANOVA; interaction location 2, efudasgicn oainefc AOA df (ANOVA; effect location signi®cant a found We rtnargyranthemus Croton .) nAgs 2±6wesatrte®e) the ®res), the after weeks (20±26 August In 0.3). F ϭ 17.06, Ͼ 5 fttlhrioosisc biomass insect herbivorous total of 85% ttsia analyses Statistical P ϭ Ͻ R 1, .0) u osgicn time signi®cant no but 0.001), ESULTS F ϭ te ebvru groups herbivorous Other . 0.01, IFN .KIH N OETD HOLT D. ROBERT AND KNIGHT M. TIFFANY P P ϭ ϭ Ͻ 2, .3)o time or 0.937) .1 relative 0.01) F ϭ 3.21, Ͻ 5% P ihs est fototrn a ntebre edge burned the HSD; in (Tukey's was orthopterans of density highest neir(0 nietebr) aaaenmeso Or- of numbers are Data burn). 0.1-m the twenty from inside burned thoptera and m burn), outside the (500 inside just just and m interior m May (10 (10 edge in edge burned burn), unburned sites the locations: burned three recently at three August from Number Orthoptera (A) USA. of Florida, north-central ecosystem, sandhill igihidvdasi ufmle ihntefml Acri- family the Crytacanthacridinae). Oedipodinae, within (Melanoplinae, subfamilies didae in individuals tinguish ®e,btfudn vdnefrsc eei edge generic a in such for interested evidence were no we found that but effect (®re), edge than particular rather general, the in perhaps edges to that responding concerned were were insects We recolo- distance. in areas if limited burned into expected is back dispersal is but which ongoing is 1A), nization (Fig. date, time diminishing sampling slowly through later be might the pattern for the that interior suggesting the in were terans cation oecs etraentsgicnl ifrn ewe lo- hsd, between (Tukeys different date sampling signi®cantly the within not cations are letter lowercase ohi h nundeg n h unditro (Tu- interior burned the HSD; and key's edge unburned the in both ls(means ples r de asrpeetnmeso rhpeafo twenty the from from Orthoptera of distances numbers 0.1-m different represent 1) Bars at (Ordway edge. site area ®re burned adjacent recently unburned a and in Orthoptera of Number F IG 2 a in sites at ®re after Orthoptera of Abundance 1. . udasadtosepntsmls iltpsdis- types Fill samples. net sweep two and quadrats ϫ ieitrcinidctsta oeorthop- more that indicates interaction time Ϯ P 1 SE Ͼ P cosaltrests.Br ihtesame the with Bars sites). three all across .) h agnlysgicn lo- signi®cant marginally The 0.2). Ͻ .3,adnmeswr equal were numbers and 0.03), 2 udasadtosepntsam- net sweep two and quadrats clg,Vl 6 o 3 No. 86, Vol. Ecology, P Ͻ .5.(B) 0.05). March 2005 FIRE GENERATES SPATIAL MOSAICS OF HERBIVORY 591

FIG. 2. Herbivory on eight plant species in the edge (10 m from the ®re edge) and interior (500 m from the ®re edge) of three burned sites in May and August. Data are means Ϯ 1 SE; the average percentage leaf herbivory was estimated from 10 plants per species at each location. effect on abundance (Fig. 1B). In the burned, but not of the direct impact of the ®re in reducing insect her- the unburned, areas, distance from edge had a strong bivore abundance, and a lag in recolonization by these effect on orthopteran abundance; this pattern is con- taxa. This pattern is expected since the dominant her- Reports sistent with the hypothesis that these insects were di- bivores in this system should be displaced by ®re. Many rectly reduced by the ®re and had recolonized burned species of sandhill grasshoppers overwinter as adults areas from unburned areas. or nymphs (Squittier and Capinera 2002), including The effects of ®re on insect abundances were par- Achurum carinatum, the most common species in our alleled by dramatic spatial variation in herbivore dam- early surveys. Because both adults and nymphs are age. For most plant species, leaf chewing was the most wingless, it is unlikely they could escape early spring destructive damage (in terms of tissue loss), although ®res. However, other species of grasshoppers overwin- species varied in the proportion of different types of ter as eggs underground. For example, another common damage they received. For example, turkey oaks (Quer- sandhill species, Melanoplus rotundipennis, is almost cus laevis) received a large proportion of mining dam- entirely in the egg stage during the February and March age (see also Kerstyn and Stiling 1999), whereas ¯ag ®re season (Squittier and Capinera 2002). We found pawpaw (Asimina incarna) received only leaf-chewing that this species was also more abundant in the edge damage. We only present data on total leaf damage, than in the interior of the burn. This suggests that even because this is the response variable most pertinent to though prescribed ®res in these sandhill ecosystems are the plants. In May, 7±13 weeks after the ®res, there low in intensity, they either kill underground eggs or was at least a four-fold greater amount of damage to otherwise reduce hatching success. most of the plant species at the edge compared to the Even more than 20 weeks following a ®re there was interior of the burn (a signi®cant effect of location; a strong effect of spatial location on both insect abun- Appendix, Fig. 2, Plate 1). In all but one species (Rhyn- dance and the amount of herbivory received by plants. chosia reniformis), there was a signi®cant time effect; Most grasshoppers at our sites spend a signi®cant pro- plants had more damage in August than in May (Ap- portion of their lives as ¯ightless juveniles (Squitier pendix, Fig. 2). Four species had a signi®cant (or nearly and Capinera 2002), which are likely ineffective at signi®cant) location ϫ time interaction; differences be- long-distance dispersal. Moreover, many species of tween burned edge and interior were more pronounced sandhill grasshoppers, including some of the most com- in May than in August (Appendix, Fig. 2). mon species in our study (A. carinatum and M. rotun- dipennis), are brachypterous (wingless) as adults, and DISCUSSION are likely to experience dispersal constraints. We have shown that a localized disturbance such as Our study lasted only one season, and so it is an ®re can have strong, predictable effects on the spatial open question as to how long the spatial signal of the pattern of trophic interactions. Interior plants may in- ®re on orthopteran abundance and herbivory will last. directly enjoy a respite from insect herbivory because Another study on small burned plots in Florida sand- Reports fgasopra h iewas site the species at recovery dominant grasshopper the long of that the fact this the in Surprisingly, despite occurred rebound burn. time took to the it grasshoppers of that for interior found years (1996) two Redak the nearly and of Porter center ®re, grass- California land the larger much a to in However, get plots. small more quickly in and could 2001) results al. grasshoppers ®re et Radho-Toly a e.g., after foliage, nutrients nutrient-rich soil edible 1999). more of became Stiling pulse plants and (the because likely (Kerstyn most ®re is a This abundance following in years increased in grasshoppers that found hills 592 ml,ioae netppltosmyb naal of incapable be that may argued populations have insect entomologists isolated small, ®re, Despite of lost. be bene®ts would to these adapted ecosystem are insects the these ®re, which without Moreover, abundance quality. host-plant nutrients increase and releases may which Fire soil, the 2002). into Panzer 2000, long-term Schwartz 2001, and the Swengel Panzer in 1999, Stiling insects and herbivorous (Kerstyn pos- on indirect have effects may ®re itive However, insects. on ®re of herbivory. release insect temporary a from have to a plants allowing of proportion area, ``interior'' greater more provide would a Larger manage- burns species. of plant similar sandhill a burns bene®t may that strategy require suggest ment would results conser- Our species the size. rare that larger this grass- suggested a He of in (USA). vation burns large Maine of in interior land the to edge the from ndpatseis otenbaigsa ( star threat- blazing a northern ®re. on species, to predation plant seed respond ened that to found community (2002) plant Vickery the of affect ability may the herbivores insect ecosystems, ®re-obligate future. the the between in locations community interior plant and the edge in herbivory- see shifts to expect mediated would we then edge sites, the burned at of ®tness If plant decrease dynamics. indeed does population herbivory and may window ®tness time lifetime critical 2003). in¯uence this Putz during and herbivory Heuberger Thus, 1990, (Myers ¯ush nutrients a of and competition for reduced long-lived on these important capitalizing for be species reproduction may and herbivores. burn growth to of a pulses tissue after leaf period their the many of Second, high; are 30±40% edge lost reasons. burn plants the two at for levels ®tness herbivory First, plant the study lifetime this that decrease of frame could suspect time the we during translate observed will Nevertheless, herbivory loss ®tness. tissue this damage, plant how of into know not amount do the we measured and interior. only burn the we to relative However, edge the at herbivory more grasshop- ``migratory the per.'' is name common ¯ights, whose long-distance and of capable grasshopper winged a riosa u td oue nteimdaengtv effects negative immediate the on focused study Our lhuhotnoeloe ntemngmn of management the in overlooked often Although 220% experienced study our in plants average, On var. novae - angliae ,dcie ln transects along declined ), eaolssanguinipes Melanoplus IFN .KIH N OETD HOLT D. ROBERT AND KNIGHT M. TIFFANY iti sca- Liatris , rswudb xetdt xeinemr herbivory. more small experience to following expected be reemerging would ®res inter- plants plant±insect because and actions, different ®tness profoundly plant have for could consequences ®res large few small a several as or occur ®res whether identical sequences, under temporal even However, and has considered. ®res Amarasekare been of rarely (e.g., arrangement spatial persistence the 2001), plant Possingham on ®res sequence empirical temporal of the and of theoretical effects elucidating much done ecosystem. work been the size on has and effect there its (temporal) While determine frequency ®re of the (spatial) Both herbivores plants. between interaction and the the determine of will strength system The overall the herbivores. of affects con®guration negatively spatial and positively (®re) plants disturbance affects and study, theoretically our In both empirically. neglected been in- have trophic on teractions disturbances of consequences et spatial However, (Power 1998). the Wootton levels 1996, al. trophic et Wootton different 1996, al. in species abun- of the dance in¯uence differentially may disturbance that ®re extinction. the from local during of risk refuge losses the facing population temporal without populations from insect rebound and have land- ®re can a such after can In insects herbivorous evolved. plants species sys- these natural scapes, the which land- replicate in to heterogeneous tems protected and be must large sug- scapes results suf®ciently Our sur- that 2003). situ (Panzer gest in species increases these that of patchiness itself vival site or there burned nearby, if the burns refugia within large unburned tolerate to adequate In- able 1998). are be al. only et Dietrich may 1997, sects Schlicht Reed 1992, (e.g., Orwig burns and management repeated surviving atel .S,C onr n .F aa.20.Hwpred- How 2001. Fagan. F. W. and Cosner, C. S., R. Cantrell, itih .H,M .Hre,R .Lrmr,adP A. P. and Larimore, L. R. Harper, G. M. 2001. H., Squitier. C. M. Dietrich, J. and Scherer, W. C. L., J. Capinera, ok .E,adJ .Bc.19.Rsos fgrasshoppers of Response 1991. Bock. H. J. and E., C. Bock, dynamics Patch 2001. Possingham. H. and P., Amarasekare, a upre yteUiest fFoiaFoundation. Florida of University identi®- the insect by research with supported This comments. was assistance valuable and for collection, support, data Chase logistical cation, J. for Poplin especially W. and and Coates useful S. their Peters, S. for and D. reviewers suggestions, anonymous group), comments, three and and laboratory Robertson, discussions K. (and helpful Marquis for R. Robinson Kim, T. Joern, oetertcladeprclwr a suggested has work empirical and theoretical Some tricrin fetciia ac ie h oeo the of role the size: Naturalist patch American response. critical functional affect incursions ator 167. esn.19.Iscsad®e o uho odthing. good a of Reports much History too Natural ®re: Illinois and Insects Florida, 1998. Tessene. of Press University USA. Florida, Florida. Gainesville, of Grasshoppers oagasad mrcnMdadNaturalist Midland Ari- southeastern American a grassland. in zona wild®re to Acrididae) (Orthoptera: spe- Biology successional Theoretical of of case Journal the cies. theory: metapopulation and etakW ok .Frnr .Faz .Gro,A. Gordon, D. Franz, R. Forkner, R. Cook, W. thank We A L CKNOWLEDGMENTS ITERATURE C 349 ITED clg,Vl 6 o 3 No. 86, Vol. Ecology, :5. 209 :333±344. 158 :368±375. 125 :162± March 2005 FIRE GENERATES SPATIAL MOSAICS OF HERBIVORY 593

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APPENDIX A table presenting ANOVA results for each plant species of the main effects of location, time, and their interaction on the total precentage of vegetative herbivory observed is available in ESA's Electronic Data Archive: Ecological Archives E086-031-A1.