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Wildlife Concerns Updates

An Overview of the International Ecology and Management Workshop

JIMMY D. TAYLOR 11,USDA, APfIIS, Wildlife Services, National Wildlife Research Center, Olympia Field Station, Olympia, WA, USA DAVID L. BERGMAN, USDA, APHIS, Wildlife Services, Phoenix, AZ, USA DALE L. NOLTE, USDA, APHIS, Wildlife Services, Fort Collins, CO, USA

ABSTRACT On 9- 12 October 2007, the U.S. Department of Agriculture, and Plant Health Inspection Service, Wildlife Services (WS) hosted the International Beaver Ecology and Management Workshop in Chandler, Arizona. The workshop was jointly sponsored by the Multi-City Sub-Regional Operations Group (SROG), Tres Rios Ecosystem Restoration and Flood Control Project and WS. The SROG management is comprised of representatives from the cities of Phoenix , Mesa , Glendale, Scottsdale, and Tempe. The workshop emphasized the management of beaver , their ecology, the part they play as a keystone , and the issues they cause as an outside of the . The workshop began with a keynote address by Dr. Dale Amer on "Historical, economical, and ecological aspects of beaver restoration and management. " The keynote address was followed by a session on beaver ecology throughout . The workshop participants were updated by several papers on "Developing Research Tools" wherein the latest advances in technology were presented . The 2nd day of the workshop began with a 2nd keynote address by Dr. Dietland Millier-Schwarze , "Knowing beaver behavior as a basis for good management." In North America, the perceived values of beaver range from negative (causing extensive damage) to positive (ecosystem engineer that promotes biological diversity) ; while attitudes towards beaver in may be more strongly negative as beave r are an invasive species that destroys native biodiversity. To address beaver damage, several pap ers add resse d the use of individual beaver manage ment techniques , cooperative programs , and changing beaver behavior. The workshop ended with the challenges and successes in developing population genetic models for . Beaver management continues to be a worldwide affair with a number of success stories and a number of questions remaining to be answered. The workshop was well attended with 75 registrants representing 5 countries and 16 states.

KEY WORDS beaver , biological diversity , , Castor canadens is, ecosystem engineer , management , North America, nuisance , South America significance m North America, North American beaver (Castor comparatively little scientific research has canadensis), hereafter beaver(s) , are been published on beaver compared to other, ingrained in Native American culture in perhaps more charismatic species. For North America along with the (Canis example, in a simple search using scientific lupus), bison (Bison bison), and names in Scopus, July 2009, we found 426 (Haliaeetus leucocephalus) . They also are a articles contammg "Castor canadensis" significant part of the culture of European compared to 3,300 articles for "Cervus settlers in North American as their images elaphus"; 2,147 for "Odocoileus are found on coins, flags, and historical virginianus"; and 1,637 for "Canis lupus". roadside markers. The quest for beaver pelts Additionally, we found only one book almost extirpated the species from North (Millier-Schwarze and Sun 2003) and one America in the 19th century; however, the published proceedings (Busher and conservation efforts of the 20th century that Dzi~ciolowski 1999) summarizing beaver led to their recovery provide one of the research . greatest success stories in modem wildlife Throughout North America , management. Despite their histo1ical management for beaver ranges from

Proceedings of the 13th WDM Conference (2009) 225 J. R. Boulanger , editor reintroduction of individuals for wetland organizations; and academia from 5 restoration to lethal removal of individuals countries and 16 states. causing damage . Introduced North In this paper, we summarize the key American beaver in Europe, along with their points of the presentations delivered at the congener European beaver (Castor fiber), workshop. Where research presented at the are managed similarly. Introduced beaver in workshop has since been published, we refer South America are considered unwanted, to cited results accordingly. However, in the exotic species that are destroying native absence of published work , we have diversity at an alarming rate. Where beaver refrained from listing specific data of others cause damage at the human-wildlife presented at the workshop. Thus, our interface, they are often referred to as discussion of their presentations is limited to nuisance beaver. Where their damming the general context of their abstracts. efforts are desirable, they are referred to as Presentations were given in the following ecosystem engineers. Because of the sessions: beaver ecology; developing competing values associated with beaver research tools; beaver biology and behavior; and the large number of laws, regulations , beaver as an invasive species; management; and opinions guiding their management or and genetics. lack thereof, we felt it necessary to bring natural resource managers and policy BEA VER ECOLOGY makers together to discuss current and future Beaver are often referred to as wetland beaver research and management topics . engineers because of their ability to create On 9- 12 October 2007, the U.S. and maintain standing water through Department of Agriculture, Animal and building. They also are described as a Plant Health Inspection Service, Wildlife because of their significant Services (WS) hosted the International impact on ecosystem structure and function . Beaver Ecology and Management Workshop The wetlands created by beaver are well in Chandler, Arizona to exchange documented as habitat for other vertebrates. knowledge of current beaver management One speaker described the positive and research and to highlight work ecological value that beaver ponds have on conducted on Ires Rios Ecosystem bird diversity in the southeastern United Restoration and Flood Control Project (see States . In a study conducted on 5 paired sites Taylor et al. 2008). The workshop was in Mississippi, she reported that beaver jointly sponsored by the Multi-City Sub­ wetlands supported more birds with Regional Operations Group (SROG) , Ires declining populations and higher Partners in Rios Ecosystem Restoration and Flood Flight conservation concern scores, and that Control Project , and WS. SROG their cumulative conservation value was 4- management is comprised of representatives fold higher than that of birds in adjacent from the cities of Phoenix , Mesa, Glendale , upland habitat. Another speaker described Scottsdale, and Tempe. The workshop was how beaver wetlands in the southeastern well attended with 75 registrants. Thirty­ United States provide quality nesting, brood­ four presentations were delivered including rearing, , resting, and roosting keynote addresses by 2 well-known beaver habitat for dabbling and perching ducks. He researchers: Dr. Dale Arner and Dr. Dietland went on the describe how proper Miiller-Schwarze . Presenters and audience management of these wetlands through members represented local, state, federal, water control, planting, and selective tree and provincial governments; non-profit harvesting can further improve habitat

Proceedings of the 13th WDM Conference (2009) 226 J. R. Boulanger, editor conditions for waterfowl throughout their fisheries and wildlife delivered presentations annual cycle. within the ecology section. The first spoke While reports of avian use of wetlands of the plans to increase public awareness , are found readily among published beaver provide leadership and strategic direction, literature, fewer studies have examined the and secure funding to increase the beneficial influence of habitat modification by beaver effects of beaver in appropriate areas within on herpetofauna. One presenter reported the state. The second speaker presented the significant reptile and amphibian use of results of a model used to delineate beaver permanent (i.e., swamps) and ephemeral habitat based on aquatic habitat inventory (i.e., pools) wetlands created by beaver in data. His preliminary results indicated that the Interior Flatwoods Physiographic Region some metrics captured in the inventory can of Mississippi . She submitted that be useful in predicting beaver presence . identification and protection of these areas Furthern1ore, he recorded that beaver in this may be necessary to promote diversity of region can be grouped as 1) those that build herpetofauna on public lands in this region . in smaller and 2) those that Beaver wetlands also promote habitat for occupy larger streams, forgo dam other . In the southeastern United construction , and live in bank dens. He States, beaver flooding and gnawing activity submitted that future research , restoration promote cavity formation in trees such as attempts , and development of management baldcypress (Taxodium distichum), plans should recognize the impacts of these sweetgum ( styraciflua) , and behavioral differences . black tupelo (Nyssa sylvatica), which Beaver population growth is influenced provide maternal and overwinter roost sites by many factors . One presenter reported the for at least 6 species of bats. These wetlands results of a 6-year study comparing the also support abundant flying insect ecology of beaver on 2 distinct study sites: communities and surface water for bat riverine habitat in central Illinois and foraging and drinking. In a study conducted forested wetland complexes of southern on 1,100 ha of bottom land hardwood forests lllinois . Based on over 600 captures and on a national wildlife refuge in northeastern over 160 radio-tagged beavers, he reported Mississippi , one presenter documented that density of both studied populations was at or bats used 12% of cavity trees surveyed. near biological carrying capacity , and noted Included were 2 species of concern: similarities among natality and causes of Rafinesque's big-eared bat (Cory norhinus mortality. He reported differences among rafinesquii) and southeastern myotis (Myotis age-specific survival , seasonal home range aus troriparius ). size, and dispersal rates and distances . Research studies have demonstrated both Timber harvest practices can influence positive and negative effects that beaver habitat conditions which affect beaver dams have on assemblages . Effects vary habitat quality and use. One presenter with numerous physical factors and the fish described how timber management species involved. In the Pacific Northwest , guidelines in , Canada restrict timber management efforts to promote federally harvest around water bodies to protect water threatened coho salmon ( Oncorhyncus quality and fish habitat , and how these kisutch) recovery include management of doughnut -shaped forests may become complex in- habitats which beaver dominated by or shade tolerant provide through dam building. Two speakers hardwoods , thus reducing habitat quality for from a northwestern state department of beavers. He presented a model to predict

Proceedings of the 13th WDM Conference (2009) 227 J. R. Boulanger , editor colony longevity based on the amount of observing variable differences in shoreline adjacent to colonies that 1s physiological parameters and found clearcut. ketamine /medetomidine was 100% and 88% predictable for high and medium dosage DEVELOPING RESEARCH TOOLS rates, respectively. He recommended using Radio telemetry has been used to monitor ketamine /medetomidine for injectable survival and movement of beaver; however , anesthesia and recommended reversal using data collection has been hampered by the atipamazole. inability to keep external transmitters on individuals and the short range of internal BEA VER BIOLOGY AND BEHAVIOR transmitters . One presenter discussed a study Classic beaver literature suggests that beaver which found modified ear-tag transmitters are monogamous and colonies consist of an fitted with plastic sleeves were retained 3- adult pair and their first-order relatives. One times longer than previously reported (Arjo presenter in this session found extra-pair et al. 2008). She went on to report that the mating between members of neighboring addition of a neoprene washer to the design colonies and documented multiple paternity increased retention time in the field by 89% in 5 of 9 (56%) litters sampled in Illinois (Arjo et al. 2008). This improvement to (Crawford et al. 2008). They found colonies existing technology will allow researchers to composed primarily of 1st- and 2nd -order monitor beaver for longer periods, thus relatives but also found unrelated utilizing more battery life and decreasing the individuals in colonies (Crawford et al. need for frequent recapture to remark 2008). Their findings shed new light on the individuals . classic literature and indicate that polygamy Immobilizing and achieving anesthesia occurs in beaver populations and that in beaver is necessary for certain field colonies vary widely in composition. procedures , such as attaching or implanting Another study looked at beaver radio transmitters. Two presenters discussed demographics in the southeastern United studies which evaluated immobilizing agents States. Data from 562 beaver collected in 7 for anestheti zing beaver. The first evaluated states (AL , GA, MS , NC , SC, TN, and VA) Telazol ® (tiletamine hydrolchloride and were grouped by physiographic region zolazepam hydrochloride) and found it (Mississippi alluvial valley , piedmont, and effective for immobilizing beaver in the coastal plain) and age (1, 2, 3, 4, and >4 field with a mean induction time <5 year-old). Colonies from all regions minutes , although mean release time (129.5 primarily consisted of 1, 2, and >4 year-old min , SE = 11.3) was long (Swafford 2002) . individuals. By weight and 3 morphometric The presenter cautioned those using Telazol measurements , beaver from the Mississippi on beaver to be patient during the recovery alluvial valley were larger than those from period and not to release beaver too early . other regions . The second presenter on chemical The final presentation in this session immobilization discussed results of a study described beaver movement and behavior on comparing 12 injectable anesthetic protocols a wetland restoration site in suburban and 6 reversal agent protocols using various Phoenix , Arizona . In this study , 43 adult doses of ketamine /xylazine , beavers (31 females and 12 males) were ketamine /medetomidine , ketamine / captured, radio-marked, and monitored acepromazine, tiletamine/zolazepam , along a 14-km stretch located along the yohimbine , and atipamazole. He reported confluence of the Salt , Gila, and Agua Fria

Proceedings of the 13th WDM Conference (2009) 228 J. R. Boulanger , editor Rivers. Only 2 individuals dispersed from beaver from the archipelago and the the study site and these movements occurred mainland . She described failed attempts to during a major flood event. Beaver moved reduce beaver numbers through economic along the linear water course and mean incentives and the pending ecological movements of females from fall 2004 disaster following further expansion of through summer 2007 were slightly greater beaver throughout continental South than males. Mean beaver movement differed America . Faced with this threat , by age class with I year-olds moving farther governments from and than 2 year-olds and 3+ year-olds . All convened 2 international workshops. From movements were shorter and less frequent these workshops , a bi-national strategy for from April through September. The beaver eradication was agreed upon to presenter also noted the observation of address and correct the threat to biodiversity multiple lactating females sharing in South America. communal den sites during kit-rearing Within the same timeframe that beaver periods (Fischer et al. in press; see genetics were introduced into , section below). nutria (Myocastor ) from South America were introduced into several states BEA VER AS AN INVASIVE SPECIES in North America. One place where nutria As beavers were relocated across North were released and established was America in the 1940s, they also were Maryland's Eastern Shore of the introduced to the Tierra del Fuego Chesapeake Bay. By the 1970s, feral archipelago in the countries of Argentina populations of nutria were estimated in the and Chile in 1946 (Silva and Saavedra tens of thousands and it was hypothesized 2008). One presenter from this region their habitat use was destroying the marsh described the history of beaver invasion and ecosystem. Their role in marsh was the impacts beaver have had on native confirmed in the 1990s and a program to biological diversity. She noted that the eradicate nutria from the Delmarva original 25 pairs of beaver have expanded to Peninsula was initiated in 2002 . The final approximat ely 100,000 individuals and presentation given in the invasive species beaver have reached the main continent. session described this ongoing program to Throughout their path , they have altered eradicate nutria , as it may be applicable to terrestrial and aquatic ecosystems through eradication of North American beaver in foraging and flooding . Their damage and South America. destruction have transformed lotic into lentic systems , opened forest canopies, and altered MANAGEMENT soil fertility. The consequences have been The management session was the largest of restructuring of the vegetative communities , the workshop and presentations ranged from which has had cascading effects on native hands-on demonstrations of trapping invertebrates and vertebrates. These techniques to WS state program overviews alterations have provided suitable habitat for to scientific research studies. The first exploitation by other exotic species, such as presenter in this session discussed the tools (Ondatra zibethicus) and trout and techniques used in trapping beaver and (Salmo trutta). described in detail how improvements and A second speaker from this region modifications have been made over time to discussed the history of beaver management increase capture efficiency and improve in Tierra del Fuego and efforts to eradicate animal welfare . He did an excellent job of

Proceedings of the 13th WDM Conference (2009) 229 J. R. Boulanger , editor describing how trapping terms and The next presenter gave an overview of nomenclature are misused . For example , a cooperative multi-organization beaver many trap model s are mistakenly referred to management plan to protect coldwater as "Conibear s" when they should be ecosystems in a midwestern state. In described by their specific manufacturer and Wisconsin , (Salvelinus model or in the group of "body-gripping fontinalis) are found in cold streams with traps". Cable devices also are mistakenly very low gradient which can be negatively called snares which connote death by affected by beaver dams. Specifically the strangulation , when in fact cable devices can dams alter soil and water conditions, silt be used to safely live-capture individual spawning areas, and block trout movement. . His presentation included He discussed unsuccessful early beaver demonstrations of specific tools and allowed management programs which included audience members to interact. trapping and dam removal by contract The next 3 presentations described WS trappers, allowing more liberal beaver perspectives on beaver management in 3 harvests on classic trout streams , trapping by reg10ns of North America. The first Wisconsin Department of Natural Resources described an overview of beaver and United State Forest Service personnel, management programs in the southeastern and beaver subsidy payment programs (i.e., United States . In general , beaver populations bounty harvest). He went on to describe how were nearly extirpated throughout the this cooperative program has benefitted the Southeast by the tum of the 20th century . coexistence of trout, beaver, and humans Following successful restoration efforts in over a large area in Wisconsin. the 1940s and ' 50s, beaver populations Understanding the history of beaver increased and recreational trapping for management is important in designing and beaver pelts was popular. With decreasing implementing current and future prices and sport harvest , complaints management plans. Beaver are widely about beaver damage have increased distributed in Arizona but are not significantly with increased urbanization and overabundant in any area in the state. One human population growth . Sources of presenter gave an overview of the history of complaints include damage to property , beaver management in Arizona dating back highways , bridges , timber, and agriculture. to the rnid-l 820s (see Carrillo et al. 2009) . Public demand for assistance has led to Removal or partial removal of beaver several approache s to reduce beaver dams is a necessary tool used by natural damage. The first presenter gave an resource managers . Hand removal of dams overview of techniques used in the is labor intensive and the effects can be Southeast. He described the failure of some short-term, as small-scale dam breaches are approaches , such as attempts at local often repaired overnight. Explosives are an eradication and offering paid bounties for efficient , cost effective , and safe tool for beaver capture to reduce problems. He went removing dams when used properly . on to discuss multi-agency cooperative Explosives can be used to reduce one or programs that are successful in reducing more complex darns simultaneously or to damage by beaver. These programs are strategically place small breaches to place made up of several state, federal , and private water control structures. In 1988, WS organizations which collectively aim to implemented a nationwide explosives use reduce human-wildlife conflicts. and safety program centered around standardized , application-specific training

Proceedings of the 13th WDM Conference (2009) 230 J. R. Boulanger, editor and certification requirements for WS have been made to allow fish passage (Close explosives specialists . One speaker 2003) . Nolte et al. (2000) found that described this program , how it represents a management objectives associated with model federal explosives safety and Clemson pond levelers were closely compliance program , and how it has led to correlated with owner satisfaction. That is, certification of 225 explosives specialists in devices installed to manage wetland for 26 states. waterfowl habitat were generally considered Several tools and techniques have been successful while devices installed to provide used for nonlethal control of beaver water relief through perpetual flow were less including repellents , physical barriers , and successful (Nolte et al. 2000). Furthermore , habitat modification ; however , few studies Nolte et al. (2000) found that levelers placed have used a scientific design to evaluate in sites with high beaver activity in the their efficacy . Nolte et al. (2003) reported absence of beaver removal, frequently the feasibility of nonlethal approaches used failed. Another presenter in this session to protect a wetland restoration site in provided information on the Clemson Arizona . They compared treatments Beaver Pond Leveler IL The design still established in the water and on land, minimizes the probability that currents of including an electronic frightening device , water flowing into the intake device can be an electro-shocking device (water only) , a detected by beaver ; however , it is reportedly textural repellent (land only), and fencing. more user-friendly and less expensive . The results were presented in this workshop , In addition to Clemson Beaver Pond concluding that fencing was the only Levelers , several other coined names absolute measure for preventing herbivory represent nonlethal tools to reduce beaver by beaver in this study . Because fencing can damage : Broad Brook Leveler , Cylindrical be very expensive to install and maintain , Fence System , Flexible Leveler , Trapezoidal managers must weigh the cost-benefits of Fence System , Cage Leveler , Beaver this technique . Deceiver, Pre-Dam , Beaver Baffler , Caster Human manipulation of water levels at Master , and others. These tools either beaver dams in North America can be traced control water flow, obstruct beaver from an back to at least the 1920s where Bailey outlet such as a culvert , or provide a (1927) used a 3-log drain to control water. combination of the two. Two presenters With the resurgence of beaver later in the from the Humane Society of the United 20th century , Amer (1963) modified the 3- States shared overviews of programs which log drain concept to seasonally control water utilized water flow control devices to for increased production of waterfowl forage alleviate beaver flooding problems . The first in beaver ponds. These devices were presenter discussed programs in installed in June and July, and removed in and , while the second October. More recently , controlling the flow presenter reported successful use of flow of water through a was made devices in the Coastal Plain of Virginia. popular in 1989 by the development of the Conditioning beaver to avoid preferred Clemson Beaver Pond Leveler by Dr. Gene food plants has been tested with little Wood at Clemson University (Wood et al. success (Harper et al. 2005). The final 1992). The usefulness of the device has presentation in the management session expanded from controlling water at dams to discussed the results of a series of pen controlling water in other areas such as studies designed to evaluate beaver feeding culverts at road crossings , and modifications responses to invasive saltcedar (Tamarix

Proceedings of the 13th WDM Conference (2009) 231 J. R. Boulanger , editor spp.) secondary metabolites. Kimball and future studies to ga111new knowledge of Perry (2008) theorized that saltcedar beaver behavior. palatability could be improved by topical application of fructose and polyethylene DISCUSSION glycol, while palatability of desirable plants To our knowledge this is the first time since such as cottonwood ( balsamifera) the Euro-American Congress in and (Salix scouleriana) could be 1998 that an international group has formed reduced by application of a repellent. They to discuss beaver research and management found that casein hydrolysate treatment of (see Busher and Dzi~ciolowski 1999). It was desirable riparian plants may promote evident from the discussions at our beaver foraging of invasive tamarisk workshop that new knowledge is emerging (Kimball and Perry 2008). with respect to beaver ecology; developing research tools; biology and behavior; beaver GENETICS as an invasive species; management; and The final and smallest sess10n within the genetics; however, research seems to be workshop dealt with the emerging interest in localized and unconnected. Furthermore, population genetics of beaver. As discussed some results are not published because in the beaver biology and behavior session , findings are anecdotal or ancillary. While genetics techniques were recently used by management activities appear successful in Crawford et al. (2008) to document reducing human-beaver conflicts, more polygamy in beavers . Simultaneous to research is needed to evaluate their efficacy. Crawford et al. 's study, Pelz-Serrano et al. For example , the efficacy of a device to (2009) used genetic techniques for prevent blockage of a culvert cannot focus development of 9 new microsatellite loci for on the culvert alone, but must include the North American beaver. They found all loci possible effects of beavers damming up- and were polymorphic except one, and average downstream. One also must consider that a hetero zygosity ranged from 0.13 to 0.86 per tool or technique that reduces damage in one locus (Pelz-Serrano et al. 2009). These area (e.g., watershed , state, region) may not marker s will be useful in future studies of be effective in others , as environmental the ecology and behavior of beavers . factors and social values differ markedly Another presenter in this session between areas . For example , beaver described the population structure of beavers management which benefits trout survival in along the convergence zone of the Agua the Midwest may not have the same effect Fria, Gila, and Salt Rivers in Phoenix , with all fish assemblages 111 all Arizona. Using mitochondrial DNA physiographic regions . sequences of the cytochrome b gene, she Collaboration among groups interested found the population came from a single in beaver research can expand the spatial maternal lineage. Combined with radio­ scale at which studies are conducted and telemetry data (see beaver biology and combine resources to explore multiple behavior section), genetic analyses revealed research hypotheses. One outlet to expand that multiple lactating females sharing collaboration is through the National communal dens were first-order relatives Wildlife Research Center's (NWRC) project (Fisher et al. in press). These results management system (Bruggers et al. 2002) . challenge the traditional dogma of beaver The NWRC project titled "Defining Impacts colony composition and lead the way to and Developing Strategies to Reduce Mammalian Damage 111 Forested and

Proceedings of the 13th WDM Conference (2009) 232 J. R. Boulanger , editor Riparian Ecosystems" is stationed in Arner, D. H. 1963. Production of duck food in beaver Olympia, Washington but has the capacity ponds. Journal of Wildlife Management 27:76- 81. to conduct national and international Bailey, V. 1927. Beaver habits and experiments in research . Since the workshop, WS has beaver culture . U.S. Department of Agriculture formed a beaver working group to address Technical Bulletin 21, Washington, D.C., USA. research needs across North America . The Bruggers, R. L., R. Owens , and T. Hoffman. 2002. working group is planning multi-state Wildlife damage management research needs: perceptions of scientists, wildlife managers , and research studies to develop and evaluate stakeholders of the USDA/Wildlife Services tools and techniques to reduce impacts by program. International Biodeterioration and beavers based on cooperator input and Biodegredation 49:213-2 23. prioritized by research needs. Research Busher, P. E., and R. M. Dzi~ciolowski, editors. studies will be conducted collaboratively 1999. Beaver protection , management, and utilization in Europe and North America. with WS operations and NWRC. Other Proceedings of a symposium held as part of the researchers from academia, state Euro-American Mammal Congress, July 19- 24, government agencies, and federal 1998, in Santiago de Compostela, Spain. government programs also are involved in Carrillo, C.D., D. L. Bergman, J. D. Taylor, P. research studies with the Olympia Field Viehoever, and M . Disney. 2009. An overview of historical beav er management in Arizona. Station to determine impacts of beaver on Proceedings of the Wildlife Damage roads, forests, and streams, and to evaluate Management Conference 13:234-2 42. tools and strategies to reduce damage . Close, T. L. 2003. Modifications of the Clemson pond leveler to facilitate brook trout passage . ACKNOWLEDGMENTS Minnesota Department of Natural Resources Special Publication 158, Minnesota , USA. We would like to especially thank the Multi­ Crawfo rd, J. C., Z. Liu, T. A. Nelson, C. K. Nielsen, City Sub-Regional Operations Group, Tres and C. K. Bloomquist. 2008. Microsatellite Rios Ecosystem Restoration and Flood analysis of mating and kinship in beavers Control Project , and Wildlife Services for (Castor canadensis). Journal of Mammalogy sponsoring the workshop. Special thanks 89:575- 581. Fischer, J. W., R. E. Joos, M. A. Neubaum, J. D. also go to D. Williams and K. Wenning of Taylor, D. L. Bergman, D. L. Nolte, and A. J. the Arizona Wildlife Services program and Piaggio. 2009. Multiple adult lactating female D. Stalman of the NWRC Olympia Field beavers (Castor canadensis) using one den site Station for logistical support. We also thank in the southwestern United States. Southwestern the workshop keynote speakers D. Amer Naturalist (in press). Harper, J. L., D. L. Nolte, T. J. DeLiberto , and D. L. and D. Muller-Schwarze, and the following Bergman. 2005. Conditioning beaver to avoid presenters: W. Arjo, F. Boyd, S. Boyles, C. desirable plants. Proceedings of the Wildlife Carrillo, B. Clay, C. Cummings , J. Damage Management Conference 11:354-362. Crawford , T. DeLiberto, J. Fogarty, D. Kimball, B. A., and K. R. Perry. 2008. Manipulating Jackson, J. Jones, S. Kendrot , F. Menveille , beaver ( Castor canadensis) feeding responses to invasive tamarisk (Tamarix spp.). Journal of S. Mills, K. Moore, T. Nelson, J. Paulson, Chemical Ecology 34:1050- 1056. A. Piaggio, K. Pelz-Serrano, M. Reker , B . Miiller-Schwarze , D. , and L. Sun. 2003. The beaver: Saavedra, L. Simon, C. Stevenson, S. natural history of a wetlands engineer. Cornell Swafford, and K. Thiel. University Press , Ithaca , , USA. Nolte, D. L., M. W. Lutman, D. L. Bergman, W. M. Arjo, and K. R. Perry. 2003. Feasibility of non­ LITERATURE CITED lethal approaches to protect riparian plants from Arjo, W. M., C. 0. Kochanny, J. L. Harper, R. Joos , foraging beavers in North America. Pages 75- 79 in D. L. Nolte, and D. Bergman. 2008. Assessment G. R. Singleton, L. A. Hinds, C. J. Krebs, and D. of transmitter models to monitor urban beaver M. Spratt, editors. Rats, mice and people: populations. Wildlife Biology 14:309- 317. biology and management. Australian Centre for

Proceedings of the 13th WDM Conference (2009) 233 J. R. Boulanger, editor International Agricult ural Research, Canberra, characteristics for beaver in Lowndes County, ACT, Australia. Mississippi . Thesis, Mississippi State University, Nolte, D. L., S. R. Swafford , and C. A. Sloan. 2000. Starkville, Mississippi , USA. Survey of factors affecting the success of Clemson Silva, C. A., and B. Saavedra. 2008. Knowing for beaver pond levelers installed in Mississippi by controlling: Ecological effects of invasive Wildlife Services. Proceedings of the Wildlife vertebrates in Tierra de] Fuego. Revista Chi lena de Damage Management Conference 9: 120-125. Historia Natural 81: 123- 136. Pelz-Serrano , K., A Munguia-Vega, A. J. Piaggio , M. Taylor , J. D., D. Bergman , and D. Nolte. 2008. If you Neubaum , P. Munclinger, A. Part!, C. Van Riper build it, they will come - management planning III, and M. Culver. 2009. Development of nine new for a suburban beaver population in Arizona. microsatellite loci for the American beaver, Castor Proceedings of the Vertebrate Conference canadensis (Rodentia: ), and cross­ 23:43-46. species amplification in the European beaver, Wood, G. W., and L. A. Woodward. 1992. The Castor fiber. Molecular Ecology Resources 9:551- Clemson beaver pond leveler. Proceedings of the 554. Annual Conference of Southeastern Association Swafford, S. R. 2002. Population survey methods , offish and Wildlife Agencies 46: 179- 187. immobilization approaches, and morphological

Proceedings of the 13th WDM Conference (2009) 234 J. R. Boulanger , editor