Radiotelemetric Evaluation of the Effect of Horticultural Practices on Pine and Meadow Voles in Apple Orchards: I. Rotary Mowing

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1 Universiy of Nebraska - Lincoln DigialCommons@Universiy of Nebraska - Lincoln Easern Pine and Meadow Vole Symposia Wildlife Damage Managemen, Inerne Cener for March 1981 Radioelemeric Evaluaion of he Effec of Horiculural Pracices on Pine and Meadow Voles in Apple Orchards: I. Roary Mowing Dale Madison Sae Universiy of New York a Binghamon Randall FizGerald Sae Universiy of New York a Binghamon Ralph Pagano Sae Universiy of New York a Binghamon Jeffrey Hill Sae Universiy of New York a Binghamon Follow his and addiional works a: hp://digialcommons.unl.edu/voles Par of he Environmenal Healh and Proecion Commons Madison, Dale; FizGerald, Randall; Pagano, Ralph; and Hill, Jeffrey, "Radioelemeric Evaluaion of he Effec of Horiculural Pracices on Pine and Meadow Voles in Apple Orchards: I. Roary Mowing" (1981). Easern Pine and Meadow Vole Symposia. 64. hp://digialcommons.unl.edu/voles/64 This Aricle is brough o you for free and open access by he Wildlife Damage Managemen, Inerne Cener for a DigialCommons@Universiy of Nebraska - Lincoln. I has been acceped for inclusion in Easern Pine and Meadow Vole Symposia by an auhorized adminisraor of DigialCommons@Universiy of Nebraska - Lincoln.

2 Radioelemeric Evaluaion of he Effec of Horiculural Pracices On Pine and Meadow Voles in Apple Orchards: I. Roary Mowing Dale Hadison, Randall FizGerald, Ralph Pagano and Jeffrey Hill Deparmen of Biological Sciences Sae Universiy of New York a Binghamon Binghamon, New York Absrac: Pine voles (Microus pineorum) and meadow voles (Microus pennsylvanicus) were sudied in hree apple orchard plos in he Hudson Valley of New York during June and July Seleced voles from each plo were given miniaure radioransmiers and hen racked before, during, and afer roary mowing. A oal of 11 pine voles and 6 meadow voles were racked. Home range size was much larger for meadow voles han pine voles. During mowing, meadow voles were noiceably affeced by he mower; pine voles were no. No change occurred in he area uilized before and afer mowing for eiher species, nor did any significan moraliy resul from he reamen. Voles of boh species showed a sligh bu significan endency o remain closer o he ree rows afer mowing. We conclude ha roary mowing has a negligible effec on vole movemen and survival under he condiions of his sudy. Pine and meadow voles are among he mos poorly undersood pes species in apple orchards, ye hey regularly cos eas coas apple growers millions of dollars in producion each year. Considerable effor has been spen in rying o develop effecive conrols, bu he secreive habis of voles are no easily sudied. In addiion, hese rodens have a phenomenal abiliy o recover from emporary populaion declines. The problem of effecive conrol is furher confounded by he presence of wo vole species ha have differen habia preferences, dies, and behavior paerns (~izgerald 6 Madison, 1981; Madison, 1980, 1981; McAninch, 1979; Pagano & Madison, 1981) and hence would likely require differen mehods for he mos effecive biological conrol. The presen sudy is he firs of an ongoing series of sudies devoed o measuring in wha way differen horiculural pracices acually affec he movemens and survival of boh pine and meadow voles. Radioelemery is used o overcome many of he mehodological shorcomings of previous sudies. In his sudy, we repor he effec of roary mowing on vole movemen and survival. METHODS The sudy was conduced on hree separae apple orchard plos wihin Sanley Orchards (owned by Sanley ~ohn), Modena, Ulser Couny, New York from 23 June o 7 July In he "pine vole plo," he

3 habia consised of old rees wih wide spacing beween he rows and rees. Forbs were common under he rees. Pine voles predominaed abou 4:l over meadow voles in his habia, and only pine voles were sudied here. In he "meadow vole plo," he habia consised of rees less han 10 years old, and he spacing beween rows and rees was much smaller. Meadow voles were essenially he exclusive residens in his area. Rich grass growh and more furrowed ground characerized his habia. Only meadow voles were sudied here. In he hird "mixed species plo," old rees and young ree inerplans were common. This habia was more heerogeneous in ree age and ground cover han he oher wo. Boh species of vole were equally abundan, and boh were sudied. Afer an iniial census period during May and June, we aemped o selec hree aduls of each sex of each species for radioracking from he 3 sudy plos, making 6 pine voles from he pine vole plo, 6 meadow voles from he meadow vole plo, and 6 of each species from he mixed species plo. These animals would hen be sudied inensively using radioelemery before, during and afer he mowing operaion. The radioelemery mehods used have been repored previously (Madison, 1977; llineau & Madison, 1977). The one excepion o he cied mehodology is ha, insead of being aached o collars, he radioransmiers were encapsulaed in parafin (~lvax, Minimeer) and implaned wihin he inraperioneal caviy (see Smih, 1979, for similar echniques). A one cm incision was made in he venro-laeral abdominal wall for his implan, and he incision was closed wih 4-0 suures (muscular layer) and a wound clip (skin). The voles were anesheized wih eher during he operaion, and all voles were released wihin 24 hours of he operaion. Subsequen rapping revealed ha all wounds healed quickly and ha no losses occurred because of he surgery. The radioransmier-baery packages weighed from 2 o 3 grams each (depending on he baery used), which is abou 10% of oal body weigh. From he ime of surgery on 23 o 25 June, he voles were given an addiional 5 days o recover from he surgery. Then, 20 "before" posiions were obained on each of he voles over a 40 h period from 1600 on 30 June o 0800 on 2 July. Mowing occurred beween 0800 and 1600 on 2 July, during which ime he movemens of 9 voles were observed in response o he passing of he mower. The "afer" period of 20 posiions was from 1600 on 2 July o 0800 on 4 July. The voles were colleced from 5 o 7 July o recover he ransmiers. The mower used was a racor-hauled roary mower. The roary uni was offse 4 fee behind he racor, and herefore allowed some mowing under he canopy of he apple rees. Blade heigh was variable a abou 4 o 5 inches above he surface in order o keep he blades from hiing rocks or oher objecs exending above he ground. Because younger rees had a smaller canopy, mowing was closer o he ree base in he meadow vole plo, bu here he furrowed soil gave compensaing proecion from exposure.

4 The daa were analyzed wo ways. Firs, o derive an esimae of area, he ouer poins of each series of 20 posiions were conneced o form a convex polygon. The area inside he perimeer l ine for each vole was measured before and afer mowing. A second analysis was conduced o deermine wheher voles sayed closer o he ree rows afer mowing. For his analysis, he disance from each posiion o he neares ree row was measured. For boh ypes of analyses, he number of voles wih larger or smaller areas, or wih posiions farher away from or closer o he ree row, were compared before and afer mowing using Chi square analyses. RESULTS General. Of he original 24 voles ha were expeced o be moniored wih radioelemery, only 23 individuals were given ransmiers: 6 voles in each of he pine and meadow vole plos, and 11 in he mixed species plo. Of hese 23 voles, only 17 were moniored hroughou he sudy period: 6 in he pine vole plo, 4 in he meadow vole plo, and 7 in he mixed species plo. The posiions on hese 17 voles consiue he daa se used in he analysis. Of he 6 voles omied from he analysis, one (a meadow vole) was killed by he roary mower, 4 could no be racked because of premaure baery fai lure (a problem since resolved), and one disappeared (eiher aken away by a wideranging predaor or jus never recapured afer baery failure). Home range size was conspicuously differen beween pine and meadow voles (Table I). Five of he 6 home ranges for meadow voles were larger han he 11 ranges recorded for pine voles ( ~ i ~ s 1,2,3).. For meadow voles, males ended o have larger home ranges han females, bu he small sample size precludes any conclusive saemen. No such rend exised for pine voles. Finally, meadow voles rouinely moved beween rows, whereas pine voles rarely did so. Five of he 6 meadow voles had ranges spanning 3 o 5 rows, and he one female ha remained wihin a row moved along 7 rees in he row. For pine voles, only wo of he 11 voles moved ino an adjacen row, and one of hese wo did so only once. One female pine vole was unusual in ha movemens occurred along 13 rees in one row (Fig. 3). Effecs During Mowina. While he roary mower was moving along he rows, he movemens of he 9 voles (4 pine, 5 meadow) wih radioransmiers were observed closely. A disinc difference emerged in he response of he wo species. The pine voles showed lile or no movemen (1-2 m maximum) during he 8 passes made by he mower over pine vole burrow sysems. For meadow voles, all 5 showed movemen during he 10 passes made by he mower ino heir living areas. Of he 5, 2 moved f rom 1 o 4 rees away in he same row, and 3 moved ino he adjacen rows. "Fleeing" or "rapid" movemens were observed up o 20 m ahead of he approaching mower. Only during he second pass of he mower for one meadow vole did he vole appear o ener a burrow sysem. Oherwise, all meadow vole movemen seemd o be on he surface. All pine vole movemen appeared o be underground.

5 Table 1. Home range size and disance o ree row before and afer roary mowing for pine and meadow voles during early July Sample Heans No. voles wih larger means Variable Sex N Before Afer Before Afer 2 Area (m ) - M. pennsylvanicus M F - M. pineorum 1.1 F Disance (m) - M. pennsylvanicus E k0.1 F 3 0.3f f0.2 - M. pineorum M ' F 5 0.6k k 'sample means are averages + 1 sandard deviaion of he mean values for each vole Effecs Before and Afer Mowin9 The sizes of he home ranges were measured before and afer mowing for boh species. No significan changes occurred in home range size (Table l), and no shifs in home range locaion were eviden (Figs. 1,2,3). When he disances of he posiions of each vole o he neares ree row were measured, boh pine and meadow voles sayed closer o he ree rows afer mowing. This observaion was saisically significan for ine voles (X2 = 4.45, p < 0.051, and for boh species combined (xq = 4.8, p < 0.05), bu no for meadow voles separaely. I should be menioned, however, ha he acual disances were small, usually less han one meer.

6 Fig. 1. Home ranges of male (M) and female (F) pine voles before (sol id line) and afer (dashed line) mowing in he pine vole plo. Tree posiions are shown by "+'I symbols. Rows exend roughly along a norh-souh axis. DISCUSSION AND CONCLUSIONS The daa clearly show ha under he condiions of his sudy, roary mowing has only a marginal effec on vole movemens and survival. The small bu significan adjusmens in pine vole movemen in response o mowing are somewha surprising because of he expecaion ha pine voles would no be bohered by mowing of grass above he peripheral margins of heir burrow sysems. Wha is being measured here could be a reducion in occasional surface aciviy by pine voles in hese areas. Meadow voles, in being much more wide-ranging and apparenly used o raversing open areas beween rows, showed no saisically significan changes in movemen before or afer rowing. However, heir "frenzied" response o he mower, in conras o pine voles, implies ha heir momenary aciviies are subsanially upse during roary mowing. In wha way his response migh be used for conrol purposes can only be speculaed upon a his sage in our sudies. Wha clearly has o be done is o now all he vegeaive cover beneah he apple rees. Boh vole species depend a leas o some degree on his cover, and roary mowing beween rows only rims he edges of hese l inear vegeaive refuges. I is speculaed ha if

7 Fig. 2. Home ranges of male (M) and female (F) meadow voles before (101 id l ine) and afer (dashed line) mowing in he meadow vole plo. Dos are drawn along he perimeer lines of one vole's home range o aid reading of he figure. See Fig. I for furher deails.

8 1 + + FP ibeford afer + I I I Fig. 3. Home ranges of male (M) and female (F) pine (p) and meadow (m) voles before (sol id line) and afer (dashed line) mowing in he mixed species plo. See Fig. 1 for furher deails.

9 Fig. 3 (coninued). This secion of he sudy plo is souh of he previous sec ion.

10 all he vegeaion were mown, and he clippings eiher colleced or pulverized, he meadow vole populaion would be exremely vulnerable o all kinds of loss (exposure o predaors and weaher exremes) and be forced o ener he burrow sysems along he ree rows. Jus wha effec his forced habiaion would have on he movemens and survival of pine and meadow voles is no known, bu his is one problem ha will be explored during The fac ha meadow voles do no commonly ener burrows under he sress of roary rowing suggess ha here may be some dangers in doing so. We hypohesize ha pine vole families are hosile oward meadow voles in pine vole burrow sysems. ACKNOWLEDGEMENTS This invesigaion was made possible by a research gran from he U.S. Fish and Wildlife Service (conrac ). We hank Jay McAninch, Donna Sockrahm, and Seve Whie for assisance a differen imes during he sudy. We also exend our hanks o he Hudson Valley frui growers, especially Sanley Cohn and Seve Clarke, who provided faciliies and financial and advisory suppor many imes during his and relaed research projecs. LITERATURE CITED FizGerald, R.W. and D.M. Madison Spacing, movemens, and social organizaion of a free-ranging populaion of pine voles Microus pineorum. In: Byers, R.E. (ed) Proceedings of he fifh easern pine and meadow vole symposium. Geysburg, Pennsylvania, 6 p. Pagano, R. and D.M. Madison Seasonal variaions in movemens and habia use by pine and meadow voles. In: Byers, R. E. (ed) Proceedings of he fifh easern pine and meadow vole symposium. Geysburg, Pennsylvania, 9 p. Madison, D.M Movemens and habia use among ineracing Perom scus leuco us as revealed by radioelemery. Can. Field Na. g1: 27& Madison, D.M Space use and social srucure in meadow voles, Microus pennsylvanicus. Behav. Ecol. Sociobiol. 7: Madison, D.M An inegraed view of he social biology of Microus pennsylvanicus. The Biologis (in press). McAninch, J Vole managemen sudies In: Byers, R.E. (ed) Proceedings of he hird easern pine and meadow vole symposium. New Pal z, New York, pp Mineau, P. and D.M. Madison Radioracking of Peromyscus leucopus. Can. J. Zool. 55: Smih, H. R Growh, reproducion and survival in Peromyscus leucopus carrying inraperioneally implaned ransmiers. In: C.J. Amlaner, Jr. and D.W. MacDonald (eds), A Handbook of Bioelemery and Radioracking. Pergamn Press, New York, PP