we performed this study in the soconusco region of chiapas , mexico across nine coffee plantations ranging from 600 to 1,300  m above sea level ( masl ) . the soconusco region is largely dominated by coffee agriculture ( 94% ) with small forest fragments mixed throughout the coffee matrix ( 6% ) ( philpott et al . we established 38 sites that differed in a number of local management and landscape level characteristics and established a minimum distance of at least 300  m between sites . these sites fell within nine large coffee plantations , ranging in size from 1000 to 6  ha , but most farms were 300 ha . we selected an intermediate distance ( 300  m ) between sites so as to avoid extreme differences within a given farm while still having varied landscape - level factors between nearby sites . we used a gps ( garmin gpsmap76csx ) to map an approximate 1-ha circle around each site and documented the abundance and richness of tree species  > 10  cm dbh within that area . 2012 ) was used to approximate the total number of tree species within a site . a prior study in the same area of mexico revealed that leafhopper species respond to the density of inga spp . trees ( burdine et al . 2014 ) , therefore we calculated the percentage of inga spp . per hectare in each plot . to estimate the density of coffee bushes , we established a 15    15  m sub - plot at the center of the 1-ha plot and counted all the coffee plants within the plot . we recorded shade cover using a convex spherical densiometer ( forestry suppliers , inc . , jackson , ms , usa ) at three spots in each site , 5  m away from the center of the site at 0 , 120 , and 240. in each of the three spots we measured the shade cover in all four cardinal directions . we also measured groundcover extent and groundcover species richness in five 0.5-m quadrats set at 5  m from the plot center every 72. cover was estimated using the following ranges : 01 , 25 , 620 , 2140 , 4160 , 6180 , and 81100% . to obtain landscape level factors at each sampling site , we used geographic information systems ( gis ) and measured landscape heterogeneity by digitizing the borders of forests and plantations of varying shade tree management intensity using a basemap in arcgis 10 ( esri 2011 ) . plantation boundaries were used to define rough categorizations of landscape shade management intensity based on the average percent shade cover of plantations : high- ( > 70% ) , medium- ( 3070% ) , and low- ( < 30% ) shade management . some plantations had large areas of more than one category of shade intensity level ; therefore we delineated these areas and categorized each area into its appropriate level . for each site , we calculated percent forest , low - shade , medium - shade , and high - shade coffee land - use types within a 100 , 250 , 500 , and 1,000  m radius surrounding each site . we also calculated the shannon s diversity index ( ln(p)p ) of the habitat types at these scales . the response of dependent variables to each landscape factor across these four scales were correlated ( supplementary material ) , therefore we proceeded with only the 1,000  m scale to maximize the differences between the local and landscape scales used in analysis . we tested for spatial autocorrelation in our data using mantel test of geographic distance among sites and abundance , richness , and shannon s diversity of leafhoppers . we found no significant correlations between geographic distance and abundance ( mantel r = 0.1010 , p = 0.963 ; r ade4 package ) , richness ( mantel r = 0.0897 , p = 0.884 ) , and shannon s diversity ( mantel r = 0.0640 , p = 0.892 ) of leafhoppers ( legendre and legendre 1998 ) . 
 table 1.mean and range values of local and landscape factorsmanagement factorsmeanrangelocal factors  coffee density ( per 225 m)7421154  shade tree density ( per ha)17363337  shade tree richness ( estimated per ha)291073  inga spp . in plot ( % ) 601694  herbaceous height6.52.412.8  herbaceous cover ( % ) 56.54100  herbaceous spp.6211landscape factors  high - shade coffee land - use ( % ) 28.4084  medium - shade coffee land - use ( % ) 37.2096  low - shade coffee land - use ( % ) 26.6086  forest ( % ) 7.7018  habitat diversity ( shannon s index)0.810.171.24other factors  elevation ( masl)9425951273alandscape factors were measured at a 1000 m radius surrounding site centers . mean and range values of local and landscape factors landscape factors were measured at a 1000 m radius surrounding site centers . leafhoppers were collected by sweep netting 15 coffee bushes in transects on 2 occasions between may and july of 2012 between the hours of 7:00 and 14:00 . each bush received four upward sweeps of the net starting at the base of the bush and moving upward . in addition to sweep netting , we also sampled the leafhopper community by using pan - traps in the center of each site on one occasion per site . we placed two white , yellow , and blue pans ( 350  ml volume bowls ) at the center of each plot . three bowls , one of each color , were elevated 15  cm above the ground surface and another three bowls were elevated 45  cm above the ground , using pvc piping . pan - traps were filled with a water solution of salt and liquid dawn dish soap . to make the solution , we mixed 2  kg of table salt and 80  ml of dawn dish soap dissolved in 20  liters of water ( as in burdine et al . we opened pan - traps at 8:00 and collected pan - traps at 14:00 , maintaining the same order so that all traps were open for roughly the same amount of time . we then combined the contents of all six pan - traps ( per site ) after sorting , rinsing , and storing contents in 70% alcohol . each site was defined as a replicate , with individuals combined from the two sweep netting events and the pan trap sample . we later identified all individuals of the family cicadellidae from both the sweep net and pan - trap sampling and assigned each individual to tribe within subfamilies and morphospecies based on morphological traits and the keys in wilson et al . ( 2009 ) , dmitriev ( 2003 ) , and nielson and godoy ( 1995 ) . we constructed a species accumulation curve ( maotao estimation ) in the program estimate s ( colwell et al . 2012 ) to determine if we had sampled sufficiently to capture the leafhopper community . to determine the relative significance of local and landscape factors in explaining leafhopper diversity , we conducted multivariate analysis using generalized linear mixed models ( glmm ) . due to a large number of independent variables and a large number of potential interactions between these independent variables , we first produced two smaller models , one with only local scale factors and another with only landscape scale factors before combining the most parsimonious model into a final local - landscape model ( as in stenchly et al . we tested for co linearity between independent variables via comparison of variance inflation factor ( vif ; neter et al . 1996 ) and considered a vif above 3 as a factor that was strongly collinear . we removed the landscape factor  percent medium shade  and the local factor  percent herbaceous cover  from models because these significantly increased vif and were thought to be ecologically insignificant or redundant with other factors . in all models , plantation was introduced as a random effect to account for unequal sample - size between plantations . each landscape model considered percent forest , low shade coffee , high shade coffee , and habitat diversity ( shannon s diversity ) as independent variables ( at 1000  m radii ) . each local model considered herbaceous height , herbaceous richness , coffee density , shade tree density , estimated shade tree richness , and percent inga tree spp . as independent variables . we performed model selection via comparison of akaike information criteria corrected for sample size ( aicc ) and parameter number , keeping the most parsimonious models ( burnham and anderson 2002 ) . for the final local - landscape model , the most parsimonious model was selected using aicc and all models with aicc  <  2 were examined and finally , we used model averaging to determine the importance of each independent variable ( supplementary material ) . we constructed local , landscape , and local  landscape models for the following leafhopper - dependent variables : total abundance , richness , and the abundance of the five most numerous leafhopper species ( macugonalia redundans [ fowler 1899 ] , sibovia sp . , isogonalia sp . , agallia sp . 1 , and agallia sp . 2 ) . to correct for effects of density on richness and shannon s diversity index , abundance was included as a covariate in models investigating variation in richness and in the shannon s index . we tested for the normality of dependent variable distributions by comparing the residuals of the model with q abundance and shannon s diversity index followed normal distributions we therefore analyzed these variables with linear mixed effects models with the function  lme in the  nlme  package in the program r ( r 3.0.1 ) ( pinheiro et al . we analyzed all other dependent variables with glmm assuming a poisson distributed error distributions and log - link functions , with the function we calculated marginal r of the final models using the r.squaredglmm function from the mumin package ( barto 2013 , nakagawa and schielzeth 2013 ) . we found a total of 299 individuals of 38 morphospecies . although the observed density was small , the estimated species accumulation curve approached asymptotic species richness for this coffee leafhopper community , suggesting our sampling had captured a significant portion of the leafhopper community ( fig . 2 ( nielson and godoy 1995)made up 37% ( 110 individuals ) of total leafhopper abundance . 
 fig . solid line represents mean of estimated richness and dotted lines represent the upper and lower bounds of the 95% confidence interval . solid line represents mean of estimated richness and dotted lines represent the upper and lower bounds of the 95% confidence interval . results of the linear mixed effects models revealed that the proportion of low - shade coffee land - use was positively related to the abundance of leafhoppers ( r=0.15 ; table 2 ; fig . 3 ) and shannon s diversity index for leafhoppers increased with coffee density in the plot and was found to be statistically significant ( r=0.58 ; table 2 ; fig . results for the breusch  pagan test revealed no heteroscedasticity of residuals for both models ( p  =  0.53 for richness and p  =  0.22 for shannon s diversity index ) . 
 fig . 2.abundance of leafhoppers increased with proportion of low - shade management of coffee at the landscape level.fig . 3.leafhopper richness increased with increase in average height of the local herbaceous layer ( a ) as well as estimated local shade tree richness ( b ) and a decrease in local tree density ( c).fig . 4.shannons diversity index for leafhoppers increased with coffee density in the plot.table 2.results of mixed effects models for response of abundance , richness and shannon s diversity index to local and landscape factorsestimate  semzpabundance  low - shade coffee land - use9.3  3.62.570.0163*richness  abundance0.069  0.0097.41.16e13  elevation0.001  0.00052.40.0154*shannon s diversity index  abundance0.08  0.0136.30 * * *  coffee density0.006  0.0031.990.0573 abundance of leafhoppers increased with proportion of low - shade management of coffee at the landscape level . leafhopper richness increased with increase in average height of the local herbaceous layer ( a ) as well as estimated local shade tree richness ( b ) and a decrease in local tree density ( c ) . results of mixed effects models for response of abundance , richness and shannon s diversity index to local and landscape factors local and landscape factors had differential effects on populations of individual leafhopper species . the abundance of agallia sp . 1 was significantly decreased with habitat diversity in the surrounding landscape as well as the proportion of inga spp . sites dominated by low - shade management in the surrounding landscape and at higher elevations had more sibovia sp . individuals . the effect of herbaceous height on m. redundans depended on the low - shade management of coffee in the surrounding landscape ( r= 0.37 ) . 2 was most abundant in sites at higher elevations but decreased with diversity of habitats in the surrounding landscape . 2 was influenced by the proportion of forest in the surrounding landscape ( r= 0.54 ; table 3 ) . table 3.results of mixed effects models for the response of individual leafhoppers to local and landscape factorsestimate  semzpsibovia sp . elevation0.004  0.0022.080.03769 *  low - shade coffee land - use2.3  1.032.240.02511 * agallia sp . 1  inga spp . in plot5.66 redundans  herbaceous height0.3  0.21.510.13133  low - shade coffee land - use4 .  2.41.810.07088 . low - shade coffee land - use  herbaceous height0.92  0.352.620.00883 * * isogonalia sp . 2  habitat diversity ( shannon s index)3.49  1.163.010.00257 * *  elevation0.01  0.0022.660.00782 * *  inga spp . in plot7.93 2.583.060.00220 * *  forest19.11  12.061.580.1132  forest  inga spp . in plot48.75  21.272.290.02193 * results of mixed effects models for the response of individual leafhoppers to local and landscape factors the results of this study suggest that local and landscape level coffee management factors are primarily responsible for leafhopper diversity . in particular , we found that low - shade coffee land use at large scales leads to greater leafhopper abundance , while elevation and coffee density explained leafhopper richness and shannon s diversity , respectively . the increase in total leafhopper abundance with increased landscape intensification ( low - shade coffee land use ) supports the rch ( root 1973 ) . the rch suggests that total abundance of the pest community should increase when host plant density increases . in this case , high - shade management should dilute the density of coffee relative to low - shade management . at the same time , diversified agriculture at the local and landscape scales may support higher predator populations , which could limit pests from the top down in these habitats ( bianchiet al.2006 , chaplin - kramer et al . indeed , within coffee agroecosystems , bird predation of pests is known to be greater in high shade management ( perfecto et al . 2004 ) and in plantations surrounded by a greater proportion of forest ( karp et al . the observed increase in leafhopper abundance with landscape intensification in our study may be the result of both the concentration of resources and lower predation pressure in intensified areas . nonetheless , syntheses of the literature have not always supported this hypothesis ( chaplin - kramer et al . for example , in two reviews of the literature , neither chaplin - kramer et al . our findings are therefore important in supporting the rch and/or the natural enemies hypothesis at the landscape scale . our results reflect that leafhopper richness and shannon s diversity find variable support for the rch , which suggests that leafhopper diversity should increase with increased non - crop vegetative abundance or diversity . leafhopper richness increased with elevation and shannon s diversity increased with coffee density , contrary to the rch . an increase in pest diversity with increased focal crop density could be expected if most herbivores found are specialists of the focal crop , where each species would increase due to a concentration of resources . for example , a review of the insect herbivore abundance in polyculture and monoculture crop fields found that 51.9% ( 130/220 ) of monophagous ( specialist ) herbivores increased in monocultures , while only 7.7% ( 17/220 ) increased in polycultures ( andow 1991 ) . further , 28.4% ( 19/67 ) of polyphagous ( generalist ) herbivores increased in monocultures , while 40.3% ( 27/67 ) increased in polycultures ( andow 1991 ) . however , while we are aware that at least a few of the species we studied consume coffee , none should be considered coffee specialists ( gonthier , personal observation ) . given that low - shade coffee systems have increased fertilization and planting density , it is possible that this productivity may promote herbivore diversity . greater productivity can lead to greater herbivore diversity through a number of mechanisms including : increased abundance of rare resources , greater persistence of rare species , or through density dependent effects ( siemann1998 ) . leafhoppers , like other xylem - feeding insects , are nitrogen limited ( mattson 1980 ) , thus increased nitrogen fertilization may improve the persistence of species that feed on coffee . yet another alternative explanation of increased richness with intensification could be that greater predation in high - shade coffee results in fewer species ( as in perfecto et al . hence , it is plausible that the combined effects of more readily available resources and lower predation pressure could lead to greater richness . however , we can only provide speculation and more research is needed to determine the mechanism behind this pattern . montane tropical communities , in particular , are affected by climatic changes as the temperature at lower elevations shifts to higher elevations . studies of bird and moth assemblages showed that these groups have shifted up slopes to cope with climate change ( chen et al . if climate change continues in this study region , we might expect to see more leafhopper species at higher elevations . it is also possible that more leafhopper species were found at higher elevations because they may be released from their natural enemies . a recent study conducted across the same region as this study , reported a lower abundance and richness of spiders at higher elevations . as spiders are generalist predators this finding may represent a reduction in the potential biocontrol services found at higher elevations ( hajian - forooshani et al . a simultaneous shift of biological control to lower elevations and herbivore diversity to higher elevations may be problematic to coffee production because although leafhoppers are only considered minor pests in coffee , they can be important plant disease vectors . some leafhopper species carry the bacterium ( x. fastidiosa ) , responsible for causing diseases in a number of important commercial plants like almonds , grapes , citrus , alfalfa , coffee , and ornamentals ( li et al . most of the species found in the cicadellinae subfamily have been observed to transmit x. fastidiosa ( redak et al . 2004 ) . recent reports of x. fastidiosa infecting coffee in costa rica and brazil ( beretta et al . although incidence of coffee leaf scorch or crespera disease caused by x. fastidiosa is not reported in the soconusco region of mexico , it is possible that leafhoppers pose a future risk in vectoring these diseases . our study highlights the need to understand the factors that affect the population distribution of leafhoppers in order to mitigate potential risks . only two other studies , to our knowledge , have investigated the distribution of leafhoppers across an intensification gradient of coffee agroecosystems . ramos ( 2008 ) found that species richness was positively correlated with fallows in the surrounding landscape . in addition , forest cover in the landscape positively correlated with leafhopper abundance at 100  m scale , but not at the 500  m scale . contrarily , pasture at both 100 and 500  m scales was negatively correlated with total abundance . the differences between our findings and ramos ( 2008 ) could be due to the difference in the regional land use composition . while our study area was dominated by coffee land use ( 94% ) , with only small forest fragments consisting of roughly 6% of the regional land area , ramos study area had a greater diversity of agricultural land uses ( 28% pasture , 14% coffee , 6% sugarcane , and 3% other crops ) , and a higher percentage ( 40% ) of forest cover as compared with our study area . besides agallia sp.2 , forest fragments in the surrounding landscape had no effect on any of the other most abundant leafhoppers in our study . perhaps the larger forest fragments in ramos ( 2008 ) study region resulted in strong effects of forests on leafhopper abundance . burdine et al . ( 2014 ) found that the richness and abundance of leafhoppers increases with the number of inga spp . ( fabaceae ) form n - fixing associations with bacteria and often have higher nitrogen content than other plant species . these plants could be important for leafhopper communities because leafhoppers are often nitrogen limited ( mattson 1980 ) . trees locally , did not correlate with the overall leafhopper abundance , but did correlate with the abundance of agallia sp . isogonalia sp . while our study contained a greater number of factors related to coffee agricultural intensification and covered a much larger regional extent across many more farms , burdine et al . ( 2014 ) studied leafhoppers during both the rainy and dry seasons , but did not investigate the effects of landscape characteristics . furthermore , in our study larger - scale landscape effects of management may have influenced the strength of the effect of local shade tree composition . interaction between local and landscape factors were also seen in the effects of herbaceous height on abundance of m. redundans , which depended on the proportion of low - shade coffee land use . indeed , effects of local level management factors can change with surrounding landscape and this has been hypothesized in other systems ( tscharntke et al . we found that abundance of only two out of the five most abundant species sibovia sp . and m. redundans was influenced by low shade coffee use in the landscape despite our results for total leafhopper abundance . in the case of m. redundans , the effect of the height of herbaceous cover was influenced by the proportion of low - shade coffee land use . however , we also found that habitat diversity in the landscape negatively affected the abundance of both the agallia spp . , suggesting a possible preference for a more homogeneous or simple landscape . our results indicate that coffee management at both the local and landscape level are important drivers of leafhopper diversity . although these insects in the family cicadellidae are not considered a major threat to coffee , some of them are vectors for diseases and pose potential risk to future coffee production . our results are also important in explaining the factors that play a key role for the conservation of these insects in light of global land - use change . this research was supported by a nsf doctoral dissertation improvement grant ( # 1309786 ) to d. gonthier and i. perfecto and an nsf biology postdoctoral fellowship ( # 1401874 ) to d. gonthier .