Final Report In Fulfillment Of The - Province Of British .

1Final ReportTo Tembec Industries Inc.December 1, 2008in fulfillment of thecontribution agreement (RC08-1569) between Tembec and UNBCINVENTORY OF ARBOREAL-FORAGING ANT COMMUNITIES WITHINWILLIAMSON’S SAPSUCKER NEST AREAS IN THE EAST KOOTENAYSPrepared by:Robert J. HigginsThompson Rivers University&Professor B. Staffan LindgrenUniversity of Northern British Columbia

2IntroductionThe Williamson’s Sapsucker (WISA), Sphyrapicus thyroideus, is a cavity nesting sapsucker thatis known to occur in three geographically distinct areas in southern British Columbia, includingone population in western larch forests of the East Kootenays near the city of Cranbrook (Figure1). This bird was assessed as endangered by the Committee on the Status of EndangeredWildlife in Canada (COSEWIC) in 2005 and added to Schedule 1 under the Species at Risk Act(SARA) by the federal government in 2006. This led to the commencement of recoveryplanning for the species.Preliminary research (Gyug et al. unpublished) has identified ants (Hymenoptera: Formicidae)as a critical food resource linked to WISA fledging success. This is consistent with work byWiebe (2005) in which increased foraging on epigaeic ants by the Northern Flicker waspositively associated with fledging success. In the case of the WISA, ants are obtained from treeboles (Crockett 1975) as the ants move up and down the trunk while foraging. Beal (1911)described the WISA as being more dependent upon ants during the breeding season than anyother North American woodpecker.Ants of the genus Camponotus (carpenter ants) were identified as comprising the majority of theant diet of the WISA (Crockett 1975), although Gyug et al. (unpublished) has also found somespecies within the genus Formica, in particular Formica aserva, that may also be a frequent foodsource. Both Camponotus species ants and Formica aserva are known to be dependent, in turn,upon coarse woody debris (CWD) as a nesting resource (Hansen and Klotz 2005, Higgins andLindgren 2005). Horn and Hanula (2008) reported that the short-term removal of CWD fromexperimental plots reduced the overall availability of arthropods to bole-foraging birds. This

3supports the findings of Gyug et al. (unpublished) who found that WISA fledgling successcorrelated with ant availability, which in turn, correlated with CWD volumes.The main objective of this project was to inventory the arboreal foraging ant communities atWISA nests sites of varying nest productivity in order to determine the relative availability ofCWD-associated and other ant species to the WISA in the East Kootenays. This projectinventory will contribute toward a more comprehensive examination of the degree of dietarydependence of the WISA upon CWD-associated ants in southern British Columbia (Meggs et al.2007). The specific objectives of this project were to:1.Compile an inventory of ant species/morphotypes available to WISA on the trunks of livetrees;2.Quantify the diversity and abundance of ant species/morphotypes available to WISA;3.Categorise the species/morphotype list by known or assumed habitat association (e.g.CWD, soil or rock-associated ants)MethodsSite inventory data relating to coarse woody debris volumes, live tree densities, and fledglingsuccess were previously collected by Gyug et al. (unpublished.) using Resource InformationStandards Committee (RISC) guidelines as outlined in the FIA Activity Standards Document forWilliamson Sapsucker Nests and Territories (MoE 2006). Canopy cover was measured as perRISC guidelines during trap installation. Sampling for ants followed, where possible, theInventory Methods for Terrestrial Arthropods (MELP 1998), although the requirement forsampling upon tree boles necessitated a unique sampling design.

4Sampling methodology followed Meggs et al. (2007). In this study we used trunk traps (Figure2), to intercept ants moving along the surface of tree boles. Sampling occurred within a 16 haarea centred upon the nest tree. The size of the sampling area was chosen to correspond to theknown minimum foraging area for the WISA given that adjacent nests are normally no closerthan 450 m to each other (Guyg et al. unpublished). Centred on each of the seven identifiedWISA nests (Appendix 1), twelve trunk traps were positioned every 30 degrees at a randomdistance between 10 and 225 m. Traps were not placed closer than 10 m to the nest tree to avoidoversampling the area immediately adjacent to the nest. Each trap was placed on a tree bole justabove a height of 2.5 m to avoid damage from cattle and held in place by two 13 mm woodscrews. Traps were put in place in mid-June 2008, and removed approximately two weeks later.This trapping period was selected to coincide with active foraging by the WISA for ants duringthe WISA chick-rearing season,.Samples collected following the removal of the traps were cleaned of debris and the ants sorted,identified, and then stored in 95% alcohol. As carpenter ants (genus Camponotus) have beenreported to be of significance in the diet of the WISA (Gyug et al, unpublished) these ants wereidentified to species where possible (Table 3). Ants of the genus Formica were identified to thelevel of species complexes except where anatomical features made identification to speciesreadily possible (e.g., Formica aserva). Other ants were identified to the level of genus.Taxonomy followed Bolton (2005).The number of individual ants of each species or morphospecies (i.e., taxa) in a trap wascounted, however presence/absence was used for analysis. This was necessary because theunequal distribution of ants within their foraging area generally results in unreliable estimates ofabundance. Traps placed on trails used by ants to access resources will accumulate large

5numbers of ants while a trap in close proximity may collect few making abundance basedanalysis of individual traps of little value. The relative abundance of ant taxa at each site (i.e.,WISA nest area) was determined by calculating the frequency of occurrence of each taxa fromindividual trap data pooled by site. Individual trap data were then pooled across all sites todetermine the frequency of occurrence of each taxa for WISA nest areas in the East Kootenayregion.Results include all species of ants collected, not just those suspected of being used as a foodsource by the WISA.

6Results and DiscussionBackground data are available for each WISA nest site relating to fledgling success, productivityclass, coarse woody debris volumes, live tree density, and canopy cover (Table 1).Table 1. Fledgling success, productivity class, coarse woody debris (CWD) volumes, live treedensity and canopy cover data for seven WISA nesting sites in the East Kootenays.Site lass(m3/ha)ctree ( 17.5cm)density(%)dc(H high;(trees/ha)L cupiedbut nestwithin100moccupiedUnoccupiedbut nestwithin100m fledged3 youngUnoccupieda Ohanjanian et al. (2007)b Ohanjanian et al. (2008)c Gyug et al. (unpublished)d Tembec – Cranbrook Division*Two concerns relate to these data (Ohanjanian pers. comm.). First, nest observations taken onJune 18, 2007 found only the young in WNE010 andWNE011 were old enough on the day ofobservation to meet FIA standards of successful fledgling (i.e., 22 days old). Second, nestobservations of WNE013 and WNE014 induced early fledging and anthropogenic mortality ofsome young. Number in brackets represent successfully fledged after anthropogenic-inducedmortality.

7**Each of these nests were originally designated as low productivity in this project based on thepost-anthropogenic fledged number.***Nests in which 4 or more young successfully fledged were considered high productivitywhile nests with less than 4 were considered low productivity (Gyug et al. unpublished).A few trunk traps were not recovered (Table 2). This may have been due to errors associatedwith GPS accuracy when recording trap locations, errors in GPS accuracy when relocating traps,or disturbance by human or animal activity.Table 2. The number of trunk traps set and relocated at seven WISA nest areas in the EastKootenays.Site Code Number of traps set Number of traps recovered Reason for failure to recover trapWNE0031210Unable to relocate 2 trapsWNE0101211Unable to relocate 1 trapWNE0111212WNE0121212WNE0131210Unable to relocate 2 trapsWNE0141211Unable to relocate 1 trapWNE0151212In total, 13 species or morphospecies of ants were captured in trunk traps at the East Kootenaysites (Table 3). Based on this initial determination, we anticipate that a full species determinationwould result in the identification of 20-30 species. Of the 13 taxa identified, five were carpenterants in the genus Camponotus. Several of these species require large diameter stumps or coarsewoody debris for nesting (Table 4), as their nests can become very large with up to 50,000workers (Hölldobler and Wilson 1990). Preliminary examination of WISA fecal sacs by Gyug etal. (unpublished), found carpenter ants to be the most common ant present, although they also

8tentatively identified Formica aserva as a frequent prey item. While this latter species can nestbroadly in differing habitats (Table 4), it is most commonly located nesting within CWD,especially in forests.Table 3. Ant species (Hymenoptera: Formicidae) collected from tree trunk intercept traps (Figure2) at seven Williamson’s Sapsucker (Sphyrapicus thyroideus) nest areas in the East Kootenayregion of British Columbia, Canada. Taxonomy follows Bolton (1995) except where morerecent revisions are available.FAMILY FORMICIDAESub-family DolichoderinaeTapinoma sessile (Say)Sub-family FormicinaeCamponotus (Camponotus) herculeanus (Linnaeus)Camponotus (Camponotus) laevigatus (Smith, F.)Camponotus (Camponotus) modoc Wheeler, W.M.Camponotus (Tanaemyrmex) semitestaceous Snelling*Camponotus (Tanaemyrmex) vicinus MayrLasius spp.Formica fusca species complexFormica spp.Formica neogagates species complexFormica spp.Formica rufa species complexFormica spp.Formica sanguinea species complexFormica aserva ForelSub-family MyrmicinaeLeptothorax spp.Myrmica spp.*New record for British Columbia

9Table 4. Ant (Hymenoptera: Formicidae) species sizes and known or assumed nesting sites foreach species or species complex of ants collected from trunk traps in the East Kootenay region ofBritish Columbia. Ant species sizes (anterior of head to posterior of the gaster) areapproximations derived from experience of the authors. Nesting information derived fromNaumann et al. (1999), and personal observations of the authors.Nesting habitatAnt taxonAnt length (mm) CWD RockSoilThatched nestCamponotus herculeanusMajors 8YESNONONOCamponotus laevigatusMajors 8YESNONONOCamponotus modocMajors 8YESNONONOCamponotus semitestaceousMajors 8NOYESYESNOCamponotus vicinusMajors 8YESYESYESNOFormica aserva 7YESYESYESYES1Formica rufa complex 7NONONOYESFormica fusca complex4-6YESYESYESNOFormica neogagates complex4-6NOYESYESNOTapinoma sessile2-4YESYESYESNOLasius spp.3-5YESYESYESNOMyrmica spp.3-5YESYESYESNOLeptothorax spp.2-3YESYESYESNO1.Thatching may occur but it is normally surrounding a stump or along the sides of downedwoody debris