Browsing down our natural heritage: Deer impacts on vegetation structure and songbird populations across an island archipelago

Declines in forest and woodland birds have largely been attributed to habitat loss and fragmentation. In the past decade, however, the potential for herbivores to influence bird species abundance and community composition via their direct impact on vegetation structure has also been recognised. We tested the hypothesis that deer influence vegetation structure and bird assemblages in a large island archipelago in western North America using surveys of 18 islands with deer densities ranging from 0 to over 1 deer/ha. Amongst these islands, reduced predation and hunting pressure has allowed deer populations to increase above those likely to have existed in pre-European times. Our results support a growing body of evidence that deer regulate both the cover and architecture of understory vegetation which in turn profoundly affects island bird assemblages. Deer-free islands supported the most abundant and diverse bird fauna. Iconic songbirds such as the rufous hummingbird, song and fox sparrow were abundant on islands with no deer but substantially reduced on islands with high deer densities. Only one bird species, the darkeyed junco, preferred moderate and high density deer islands. Our observations suggest that current cohorts of palatable shrubs on islands with high deer densities are relatively old and potentially represent an impending extinction debt, where the full effects of high deer density on island biotamay take decades to fully unfold. Our results suggest that deer densities below a threshold of 0.1 deer/ha should allow native vegetation to recover and a rich and diverse bird species assemblage to persist. We suggest that adaptive management be used to test the validity of this threshold, and that without active management of deer abundance, local extinctions of native flora and fauna appear likely to accelerate.

Read the entire article here (PDF):

Browsing down our natural heritage: Deer impacts on vegetation structure and songbird populations across an island archipelago (1.9 MB)

HERBIVORY MORE LIMITING THAN COMPETITION ON EARLY AND ESTABLISHED NATIVE PLANTS IN AN INVADED MEADOW

Abstract. The dominance of nonnative plants coupled with declines of native plants suggests that competitive displacement drives extinctions, yet empirical examples are rare. Herbivores, however, can alter vegetation structure and reduce diversity when abundant. Herbivores may act on mature, reproductive life stages whereas some of the strongest competitive effects might occur at early life stages that are difficult to observe. For example, competition by perennial nonnative grasses can interfere with the establishment of native seeds. We contrasted the effects of ungulate herbivory and competition by neighboring plants on the performance of native plant species at early and established life stages in invaded oak meadows. We recorded growth, survival, and flowering in two native species transplanted as established plants, six native species grown from seed, and five extant lily species as part of two 2 3 2 factorial experiments that manipulated herbivory and competition. Herbivory reduced the performance of nearly all focal native species at early and established life stages, whereas competition had few measurable effects. Our results suggest that herbivory has a greater local influence on native plant species than competition and that reducing herbivore impacts will be required to successfully restore endangered oak meadows where ungulates are now abundant.

Key words: black-tailed deer; British Columbia; competition; conservation; exotic; grass; invasive; oak savanna; Odocoileus hemionus; sheep.

Read the entire article here (PDF):

HERBIVORY LIMITS NATIVE PLANTS (2.4 MB)

Deer-related links

Lack of hunting is destroying BC’s Gulf Islands

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/4836168/Lack_of_hunting_is_destroying_

BC’s Gulf Islands Needs Hunters

http://outdoorcanada.ca/12416/hunting/big-game/why-we-need-hunters-in-b-c

BC Parks Sidney Island

http://www.env.gov.bc.ca/bcparks/conserve/occ_paper/faldeer.html

Fallow Deer Eating Their Way Across Gulf Islands

http://www.timescolonist.com/news/local/fallow-deer-eating-their-way-across-gulf-islands-1.51352

Saturna Island Fallow Deer

http://www.vancouversun.com/opinion/columnists/Stephen+Hume+battle+against+Bambi/7809432/story.html

CRD Deer Committee

http://www.crd.bc.ca/regionalplanning/deermanage.htm

Deer Friendly – Deer in the news worldwide

http://www.deerfriendly.com/

Australia and New Zealand information

http://www.feral.org.au/category/dama/dama-dama/deer-fallow-deer/

More New Zealand

http://www.readperiodicals.com/201001/1975162951.html

Hawaii Deer Issues

http://www.rarehawaii.org/deerpage/deer.htm

More on Hawaii

http://www.vancouversun.com/technology/Deer+surfacing+Hawaii+Island/6678104/story.html

Deer menace Gulf Islands habitat. Oh Deer. Or, When Laws Are Made After Watching “Bambi”

http://unambig.com/tag/mayne-island/

Deer menace Gulf Islands habitat

http://www.vancouversun.com/sports/Deer+menace+Gulf+Islands+habitat/4126622/story.html

Deer oh Deer

http://www.cbc.ca/quirks/episode/2011/01/22/january-22-2011/

Deer causing rapid environmental change on B.C.’s and Washington’s Gulf islands: UBC study

http://www.publicaffairs.ubc.ca/2011/01/17/deer-causing-rapid-environmental-change-on-b-c-%E2%80%99s-and-washington%E2%80%99s-gulf-islands-ubc-study/

The environmental costs of protecting Bambi

http://www.theglobeandmail.com/news/national/british-columbia/mark-hume/examining-the-high-environmental-costs-of-protecting-bambi/article1872391/

Adrian MacNair: B.C. deer-lovers ruining the environment

http://fullcomment.nationalpost.com/2011/01/25/adrian-macnair-b-c-deer-lovers-ruining-the-environment/

Deer Causing Environmental Change on Canadian Islands

http://www.theepochtimes.com/n2/content/view/49594/

Deer menace Gulf Islands habitat

http://www.timescolonist.com/technology/Deer+menace+Gulf+Islands+habitat/4123107/story.html

Sidney Island Fallow Deer

http://www.timescolonist.com/travel/Parks+Canada+expand+deer+cull+Sidney+Island/3798514/story.html

A Pender perspective

http://www.firhillfarms.com/wordpress/?cat=58

Scientific description of Fallow Deer

http://linnet.geog.ubc.ca/efauna/Atlas/Atlas.aspx?sciname=Dama%20dama

 

 

 

Deer Forum

On January 14, a community forum was hosted by the Mayne Island Residents and Ratepayers Association at the Ag Hall to discuss the growing deer populations on Mayne Island, their impact on the islands ecosystem and the options available to address residents concerns over deer overpopulation. Over 85 residents and stakeholders representing a broad spectrum of interests filled the hall.

Peter Arcese from UBC opened the meeting with a detailed presentation on the impacts of deer on the ecosystem when populations exceed what Mother Nature intended. Some of the photos were dramatic and validated the concerns that have been expressed by islanders in recent years. Todd Golumbia from Parks Canada related his experiences on Haida Gwaii (Queen Charlotte Islands) and, more recently, Sidney Island where deer have decimated native plant species

Peter also reminded the audience that deer overpopulation is a human caused issue. In the past there were bears, wolves and cougars on the island that kept the deer numbers down. In the past 150 years humans became intolerant of these predators and removed them from the ecosystem. Nature was kept in balance until recent times due to hunting. However, in the 1970’s hunting was banned from Mayne Island and the deer blossomed in numbers to the point we are today. There is not accurate way of assessing the number of deer on Mayne, but the numbers are well into the thousands according the knowledgeable islanders

In the 1990’s, this issue was exasperated by the escape of European Fallow Deer from a local deer farm. The Fallow deer appear to have a more aggressive feeding habit, which reduces the available food for the native Black Tail deer, pushing them to eat native plants that normally they would not touch. However perhaps the most dramatic information from the meeting came from Galiano, where it was disclosed three Fallow Deer were recently shot by hunters. This could be well interpreted as a sign the Mayne has reached ‘critical mass’ and the deer are swimming to other islands in search of a food source. There currently is a restricted permit only hunt for Fallow Deer on Mayne to control that population.

Peter stated that the sustainable number of deer that would allow a proper balance within the ecosystem would be 10 deer per square kilometre. There are approximately 23.5 square kilometres of land mass on Mayne, so the population would need to be reduced to less than 250 deer. There was general agreement at the meeting that the invasive Fallow Deer should be 100% culled and the Black Tail brought down to sustainable numbers.

In that we are in a situation caused by humans, the solution must come from humans.

It is highly unlikely that islanders will embrace the ‘natural’ solution of reintroducing bears, wolves and cougars on Mayne. Efforts in other jurisdictions to sterilize, capture or relocate deer have proven to be expensive and ineffective in both the short and long term. The only viable option is to open up hunting on island, under a set of rules developed by islanders, respecting the concerns of islanders.

It is hoped that the next community forum will be held with Provincial Government officials to explore what options are available. There are strict regulations with regard to the inspection and handling of game meat for commercial sale, which virtually eliminates the option of a commercial style hunt. However, the question has been posed to the Ministry as to the possibility of distributing meat at no cost to the community under a co-op style venture, which may circumvent the inspection requirements.

Although it was not brought up at the meeting, there perhaps is some concern as to the concept of hunting ‘innocent’ deer for the benefit of humans. It is important to point out that the overpopulation of deer is resulting in the destruction of our islands sensitive ecosystem; regulated hunting would be undertaken for the purpose of returning a balance to the island we love. Those who would like further details or information about future forums are invited to email maynedeer@hotmail.com.

I would like to thank UBC, Parks Canada, RCMP, Islands Trust Fund, the Mayne LTC and the stakeholders and residents that attended the meeting. It was a positive and informative experience and the first step to addressing a very serious issue on our island.

David Maude
Forum Coordinator

British Columbia Urban Ungulate Conflict Analysis

Deer, moose, elk, and bighorn sheep have a widespread distribution across British Columbia, providing significant public recreational opportunities and aesthetic enjoyment to BC residents. However, excellent habitat in residential areas and protection from hunters and predators has encouraged some ungulate populations to become urban dwellers. Increasing numbers of ungulates (primarily deer) living in urban areas has led to increased conflict with the human residents of those areas.

Conflicts between urban ungulates and municipal residents include damage to gardens and landscaping, high rates of ungulate vehicle collisions, aggressive behaviour towards humans, and potential transmission of disease from ungulates to humans and livestock. Across Canada, there are only a few cities where active urban ungulate management has been implemented. In 2004, Magrath, Alberta carried out a controlled hunt in the rural areas adjacent to the town to reduce the resident deer population. Winnipeg, Manitoba carried out a deer capture and relocation project in 1985, and Ottawa, Ontario implemented a deer vehicle collision public awareness campaign in 2006.

In BC, although moose and bighorn sheep cause occasional seasonal management issues, deer are the major urban ungulate management challenge. The municipalities with the greatest challenges are Princeton, Kimberley and Grand Forks. Princeton and Kimberley have resident populations of mule deer and aggressive incidents are becoming more frequent. Grand Forks has white-tailed deer, but no aggressive incidents have been noted to date. Meetings have been held with municipal governments in all three communities, and Kimberley has implemented a bylaw prohibiting deer feeding.

Urban ungulate populations are challenging to manage for biological, jurisdictional and social reasons. Deer are very adaptable to human altered environments, and thrive in urban areas. The overlapping roles and responsibilities of the municipal and provincial governments complicate management decisions. Further, the wide range of public opinion on the most appropriate management interventions presents a huge challenge, as the diversity of often opposing opinions makes for a controversial management project.

Many communities in the United States (where urban deer management has a longer history than in Canada), are undertaking community based, co-management processes, which are usually perceived to be more appropriate, efficient and equitable than traditional authoritative wildlife management approaches. Although these processes may take more time, they can result in greater stakeholder participation and satisfaction with urban wildlife management.

Urban ungulate management strategies should be focused on the reduction of conflicts and management of populations to an acceptable level, not the complete elimination of the conflict or herd. A comprehensive and integrated plan that incorporates aspects of many options is required to achieve the project objectives. Short term strategies may provide relief from symptoms, while long term plans address population levels. Provincial and community resources plus property owner cooperation are needed to achieve measurable results.

Management options fall into four categories: conflict reduction, population reduction, fertility control, and administrative options. Conflict reduction options keep ungulates away from susceptible properties, minimize the damage that is sustained if animals do enter property and reduce human/ungulate conflict. Landscape design, careful plant selection, taking preventative measures early before patterns of behaviour are established, and using repellents and scaring devices can reduce, but not eliminate, ungulate damage. Fencing is the only viable option when damage cannot be tolerated.

Population reduction programs are ongoing activities, with an initial reduction phase, when a significant proportion of the population is removed at one time, and a maintenance phase, occurring after ungulate densities are reduced and when fewer individuals are removed. Community specific management decisions have to factor in the number of animals to be removed and at what intervals, the potential for increased reproductive productivity, and possible increased immigration due to less competition for habitat and resources. Capture and relocation of deer has not often been implemented across Canada and the United States due to concerns about animal mortality post release, however, in localized areas, and under special circumstances, it may be appropriate. Sharpshooting, capture and euthanization, and controlled public hunting have all been used in the United States to reduce ungulate populations.

Fertility control options are extremely limited because no fertility control drugs are approved for general use in ungulate populations in Canada, and only one drug is approved for use in the United States. Immunocontraceptive vaccines are the most promising fertility control method and have been approved for experimental research purposes. Ongoing, long-term research reporting on the efficacy of these drugs to reduce populations and maintain them at low enough levels to keep ungulate damage at acceptable levels is just starting to emerge. For the near future, most researchers suggest that populations be lowered using lethal control, and then, when proven practical, population levels can be maintained using fertility control.

Administrative options such as amending municipal bylaws and provincial regulations to permit lethal control options need to be implemented, and public education and formal project monitoring need to be ongoing before, during and after any management interventions.

When complaints caused by overabundant ungulates are increasing in numbers and severity, then conflict reduction options such as fencing, repellents, and aversive conditioning will not significantly reduce the numbers of complaints. Population reduction is needed to reduce the damage caused by overabundant ungulates. Once the population numbers are lowered, then damage is easier to manage with conflict reduction techniques. The method of population reduction and how often it needs to be carried out is dependent on the site specific circumstances in each community.

Read the complete document here (PDF):

British Columbia Urban Ungulate Conflict Analysis (7.1 MB)

British Columbia Urban Ungulate Conflict Analysis Summary Report for Municipalities

Deer, moose, elk, and bighorn sheep have a widespread distribution across British Columbia, providing significant public recreational opportunities and aesthetic enjoyment to BC residents. However, excellent habitat in residential areas and protection from hunters and predators has encouraged some ungulate populations to become urban dwellers. Increasing numbers of ungulates (primarily deer) living in urban areas has led to increased conflict with the human residents of those areas.

Conflicts between urban ungulates and municipal residents include damage to gardens and landscaping, high rates of ungulate vehicle collisions, aggressive behaviour towards humans, and potential transmission of disease from ungulates to humans and livestock. Across Canada, there are only a few cities where active urban ungulate management has been implemented.

Urban ungulate populations are challenging to manage for biological, jurisdictional and social reasons. Deer are very adaptable to human altered environments, and thrive in urban areas. The overlapping roles and responsibilities of municipal and provincial governments complicate management decisions. Further, the wide range of public opinion on appropriate management interventions presents a huge challenge, as the diversity of often opposing opinions makes for a controversial management project.

Many communities in the United States (where urban deer management has a longer history than in Canada), are undertaking collaborative, community based, co-management processes, which are usually perceived to be more appropriate, efficient and equitable than traditional authoritative wildlife management approaches. Although these processes may take more time, they can result in greater stakeholder participation and satisfaction with urban wildlife management.

Urban ungulate management strategies should be focused on the reduction of conflicts and management of populations to an acceptable level, not the complete elimination of the problem or herd. A comprehensive and integrated plan that incorporates aspects of many options is required to achieve the project objectives. Short term strategies may provide relief from symptoms, while long term plans address population levels. Provincial and community resources plus property owner cooperation are needed to achieve measurable results.

Management options fall into four categories: conflict reduction, population reduction, fertility control, and administrative options. Conflict reduction options keep ungulates away from susceptible properties, minimize the damage that is sustained if animals do enter property and reduce human/ungulate conflict. Landscape design, careful plant selection, taking preventative measures early before patterns of behaviour are established, and using repellents and scaring devices can reduce, but not eliminate, ungulate damage. Fencing is the only viable option when damage cannot be tolerated.

Population reduction programs are ongoing activities, with an initial reduction phase, when a significant proportion of the population is removed at one time, and a maintenance phase, occurring after ungulate densities are reduced and when fewer individuals are removed. Community specific management decisions have to factor in the number of animals to be removed and at what intervals, the potential for increased reproductive productivity, and possible increased immigration due to less competition for habitat and resources. Capture and relocation of deer has not often been implemented across Canada or the United States due to concerns about animal mortality during capture and post release, however, in localized areas, under special circumstances, it may be appropriate. Sharpshooting, capture and euthanization, and controlled public hunting have all been used successfully in the United States to reduce ungulate populations.

When complaints caused by overabundant ungulates are increasing in numbers and severity, then conflict reduction options such as fencing, repellents, and aversive conditioning will not significantly reduce the numbers of complaints. Population reduction is needed to reduce the damage caused by overabundant ungulates. Once the population numbers are lowered, then damage is easier to manage with conflict reduction techniques. The method of population reduction and how often it needs to be carried out is dependent on the site specific circumstances in each community.

Fertility control options are extremely limited because no fertility control drugs are approved for general use in ungulate populations in Canada. Immunocontraceptive vaccines are the most promising fertility control method and have been approved for experimental research purposes. Ongoing, long-term research reporting on the efficacy of these drugs to reduce populations and maintain them at low enough levels to keep ungulate damage at acceptable levels is just starting to emerge. For the near future, most researchers suggest that populations be lowered using lethal control, and then, when proven practical, population levels can be maintained using fertility control.

Administrative options such as amending municipal bylaws and provincial regulations to permit lethal control options need to be implemented, and public education and formal project monitoring need to be ongoing before, during and after any management interventions.

This report provides an overview of the reasons why ungulates are present in urban environments and summarizes the consequences of overabundance. Examples of urban ungulate management projects in other jurisdictions are provided. The biological, social and administrative challenges of managing urban ungulates, a discussion of why residents’ opinions and values about wildlife need to be considered when developing urban wildlife management programs and how residents and communities in other jurisdictions have become involved in urban wildlife management programs are discussed. Management options for urban ungulates are reviewed, including discussions of efficacy, costs, human health and safety, animal humaneness, and project advantages and disadvantages. Finally, there are recommendations for the future as municipalities address urban ungulate management challenges.

Read the complete document (PDF):

British Columbia Urban Ungulate Conflict Analysis Summary Report for Municipalities (1.6 MB)