Captive Breeding Programs as the Last Resort to Species Conservation

Theodorou, K. and D. Couvet. 2004. Introduction of captive breeders to the wild: Harmful or beneficial. Conservation Genetics. 5:1-12.

Link to article:  http://www.metapress.com.ezproxy.tru.ca/content/w0t5q7822l8533r3/fulltext.pdf

Image from: http://www.cartoonstock.com/newscartoons/cartoonists/bwj/lowres/bwjn51l.jpg

A popular conservation strategy to avoid extinction of many endangered populations is captive breeding programs. This method of conservation aids in one of two ways: 1) retaining individuals in captivity until environmental or habitat conditions are adequate for the species to survive, or 2) reinforcing the existing wild populations. A well known and thoroughly investigated potential problem with captive breeding programs is loss of genetic diversity in the captive population or genetic adaptations (which are non-problematic in captivity) that are harmful in the wild (Theodorou & Couvet 2004). These genetic adaptations may include, but are not limited to, decreased wariness toward natural predators and/or humans and lowered physiological defences from medical treatment.



This paper focused on the effects of captive breeding and release of species within small wild population sizes involved in short-term programs (i.e. no more than 50 generations). In the case of a small wild population, more of the genetic diversity is coming from the captive individuals and therefore genetic load increases. This increased genetic load could lead to an increased risk of pushing the natural population to extinction. In other words, rather that these programs increasing or even maintaining the original population, negative effects could result (Theodorou & Couvet 2004).

Theodorou and Couvet stated that the original wild population fitness may be positively affected if three conditions were met: 1) introducing a small number of individuals per generation, 2) restricting the program to a short time frame (ex. having 30 generations vs. 60), and 3) having a large breeding population to enhance genetic variability (Theodorou & Couvet 2004). So, the main point here is to have sufficiently controlled (compared to relaxed) breeding programs to supplement the original populations.



My opinion: ‘Relaxed’ captive breeding programs may result in lower genetic diversity, but until a more efficient solution to species loss is discovered, this is the only hope for many endangered populations. I suppose trying is better than doing nothing! Plus, what happens when the original population is completely gone from the area and conservation efforts are ‘starting from scratch’? This paper discussed the complications with relatively ‘relaxed’ breeding programs and how these  only work for a short time frame (less than 20 generations). It should be noted that strategically planned and organized programs may be successful in retaining genetic diversity and avoiding the continuous reintroduction of deleterious alleles in the long term (Theodorou & Couvet 2004). Those involved with the planning of the burrowing owl captive-breeding program at the BC Wildlife Park have acknowledged the possibility of genetic loss to the original wild population and challenged the problem as much as possible. By having a relatively large breeding population and physically selecting individuals as breeding pairs the loss of genetic diversity can be avoided or at least reduced. Unfortunately, in this situation the original wild population does not exist (was extripated) therefore the genetic load of the introduced population is extremely high (100%). Perhaps by periodically introducing additional individuals (from alternative populations) as breeding pairs the program could be improved.  

Word Count: 502

Grizzly Bear Conservation: Is Changing Human Behaviour The Answer?

TRU Environmental Sciences Seminar

February 3, 2011, 2011 3:30-4:30

Dr. Seth M.Wilson

Department of Biology, University of Victoria

"The grassroots of carnivore conservation"

Image from: http://sonic.net/~evolve/wp/human_ecology/grizzly_bear_1a.jpg

Dr Seth Wilson has dedicated six years of his career aiming to find a healthy balance of coexistence between humans and grizzly bears (Ursus arctos) by developing a trusting relationship with a community of private landowners in the Blackfoot Watershed of Montana, US.  Agricultural and ranching economic loss due to large carnivores is a world-wide issue and statistics provide evidence for this:  45% of reported ‘conflicts’ in Montana are due to detrimental interactions with livestock.  Wilson formed a wildlife committee with a previously developed non-government organization, ‘The Blackfoot Challenge’ to discover a solution to the grizzly bear ‘problem’.  By asking the landowners to share some of their concerns, Wilson was able conclude the best management practice for grizzly bear conservation was to promote a slight change human behaviour.

A risk assessment was mapped to locate potential bear attractants and their location, and then relate this information to reported bear sightings and conflicts. Not surprisingly, there was overlap. A simple act such as placing an electric fence around beehive production reduces the risk of conflict from ~50% (without the fence) to less than 25% (with the fence). Portable electric fences have shown successful outcomes for many ranchers. Proper waste management practices are important. By forming a neighbour network to share bear whereabouts so dog food and bird feeders can be brought inside is also effective. Wilson explained that bears, having extremely good olfactory senses, are attracted to rotting carcasses of dead calves or sick animals, and grizzly bear sows have been observed teaching cubs to locate these livestock graveyards. Many ranchers have signed onto a carcass pick-up program to get animal wastes off their land to reduce the attractant.

Wilson says the project appears to be a success and preliminary results are optimistic. There has been a 93% decline in conflicts between 2003 and 2009. In the research area, there have been zero grizzly bear mortalities, livestock losses, beehive invasions, or relocations since 2005. Perhaps the bears are showing learned behaviour and avoiding the intensively managed areas only to investigate areas outside the Blackfoot Watershed research area.

The knowledge that Seth and his team have obtained is transferable to other areas. He says when ranchers hear successful results from other ranchers (rather than researchers or scientific data) they are more eager to adopt the practice.

It appears that peer-to-peer education and stewardship is fundamental to successful conservation of grizzly bears, and perhaps other large carnivores. Instead of telling people what they can or cannot do, or doing it for them, give them the basic information and let them spread the news.

My opinion:  How great is it to hear a success story of large carnivore conservation that does not result in destroying individuals! This lecture was centered around the importance of public education and the effects of altering human behaviour rather than non-human animals. In this anthropocentric world we live, it seems too often that humans are trying to physically remove wildlife from our 'bubbles'. Wilson’s research of the grizzly bear encounters in Montana makes me feel encouraged to state it might be beneficial to alter human behaviour so that rather than enticing large carnivores to invade our 'territories' and then kicking them out, we deter these animals from even wandering around in the first place.  Let's be proactive rather than reactive!

Word Count: 538

The Value of Old-Growth Forests

Goward, T. and J. Campbell. Arboreal hair lichens in a young, mid-elevation conifer stand, with implications for the management of mountain caribou. The Bryologist. 108:427-434.

Kauffman, G. D. 1979. The discovery of penicillin: Twentieth century wonder drug. Journal of Chemical Education.  56: 454-455.

Radies, D., Coxson, D., Johnson, C. and K. Konwicki. 2009. Predicting canopy macrolichen diversity and abundance within old-growth inland temperate rainforests. Forest Ecology and Management. 259:86-97.

Link to information on mountain caribou and lichens: http://www.jstor.org.ezproxy.tru.ca/stable/pdfplus/20061123.pdf?acceptTC=true

Link to information on penicillin:

http://pubs.acs.org.ezproxy.tru.ca/doi/pdf/10.1021/ed056p454

Link to information on canopy macrolichens:

http://www.sciencedirect.com.ezproxy.tru.ca/science?_ob=MImg&_imagekey=B6T6X-4XHJX5T-1-C&_cdi=5042&_user=742544&_pii=S0378112709007063&_origin=search&_coverDate=12%2F05%2F2009&_sk=997409998&view=c&wchp=dGLbVzb-zSkzV&md5=1f2751302ef2536bab630420dfab6e19&ie=/sdarticle.pdf

Image From: http://www.endangeredecosystems.org/images/oldgrowth.jpg

Approximately 27% of British Columbia is covered in old-growth forests, which comprise about 43% of all forested area in the province (MacKinnon 1998). Old-growth forests can be recognized as middle to late seral stages. At both of these stages of forest development, soil structure is stabilized and water flow control is evident. Interior species such as the spotted owl (Strix Occidontalis), squirrels (Spermophilus spp.), hermit thrush (Catharus guttatus), bears (Ursus spp.) and the endangered mountain ecotype of the woodland caribou (Rangifer tarandus caribou) rely strongly on old-growth habitat structure (Rose 2003).

Conservation practices tend to focus on the animal kingdom and how to manage a particular vertebrate or invertebrate species. The non-animal components of the terrestrial biotic world tend to get pushed aside. It seems incredibly useful to understand the role of these plant, fungi, or lichen taxa as their presence or absence can strongly affect that of other species. Some lichens and rare nonvascular plants are extremely dependent on old-growth forests (MacKinnon, 1998). In old-growth cedar-hemlock forests of British Columbia there is a high diversity of epiphytic macrolichens and bryophytes (Gavin 2009). Researchers have speculated that conifer old-growth forests support roughly 30 cyanolichen species which makes this ecosystem one of the richest collections of epiphytic cyanolichens in the entire world (Radies 2009). Most of these species are absent from younger stands.

Speaking of lichens let’s just take a short swerve off the focus of valuing old-growth forests. I came across a paper about arboreal hair lichens in mid-successional, mid-elevation forests and their significance in caribou diet. This article is interesting not only because it links endangered species to old-growth forest to conservation, but also because Trevor Goward is the co-author. Trevor Goward is partly to thank for the donation of the land where TRU Wells Gray Research Station is situated.

Goward and his research partner’s study results showed that all hair lichen species of importance to the mountain caribou were present only in forests 60 years or older. Interestingly, hair lichen biomass was greater in open stands than closed stands. This is positive because it means species of lichen important to endangered caribou will potentially benefit from stand thinning (Goward and Campbell 2005). Perhaps selective logging is the answer to the debate over old-growth forest management. This study suggests by defoliating portions of the middle canopy (or potentially selectively removing some old-growth trees), conservation of mountain caribou might be able to shake hands with the timber industry.

In addition to preserving the living organisms that thrive in them, old-growth forests are important in other ways. The structure of such forests prevents landslides, soil erosion, and floods. Old-growth forests also provide clean water for agriculture, enrich the soil, and prevent the greenhouse effect (Rose 2003). Also, this ecosystem can be valued from an aesthetic or recreational standpoint. Activities such as hiking, bird watching, backpacking, camping, hunting, fishing, among other outdoor experiences are limited without old-growth forests. The biodiversity and overall appearance of these forests contributes to the former activities being so enjoyable. If old-growth forests continue to be destroyed as they are today, the aesthetic beauty will be gone. We may want to ask ourselves if we would trade the beauty of wild animals and magnificent trees for a paper cup in which we only use for a couple hours.

The components of old-growth forests - as opposed to the ecosystem as a whole - can be used as tools for research and increasing knowledge. Humans have been utilizing the natural world for centuries. Our understanding of various species or habitats has been of huge importance in obtaining food, building homes, healing injuries, and curing diseases. The accidental discovery of a species of mould by Sir Alexander Flemming in 1928, turned out to be an extremely useful antibiotic in the realm of science (Kauffman 1979). This antibiotic, known as penicillin, has saved many human lives. If the habitat in which this mould lived was destroyed before it was discovered we may have been unable to prevent deadly bacterial infections. The same may be true of old-growth forests. Without enough time to research this type of ecosystem, we may be missing out on species that might provide the means to cure or prevent diseases such as AIDS, Ebola, diabetes, and cancer.

Arguments over the use of old-growth forests have been on-going for decades. Today, about 125 000 acres of old-growth forest is destroyed annually. It is clearly evident that jobs will be lost if the lumber industry has to decrease the rate of logging. However, these jobs would be ultimately lost if this current rate of destruction continues. Eventually, there will be no timber left for employment opportunities. A simple reforestation plan could not replace forests which have taken thousands of years to develop. Humans find value in old-growth forests and considering the anthropocentric world we live in, conservation of such a habitat is strongly recommended.

 Word Count: 815

Additional Sources:

 

Rose, S.K., and D. Chapman. 2003. Timber harvest adjacency economies, hunting, species protection, and old growth value: seeking the dynamic optimum. Ecological Economics. 44:325-344.

Mystified by the Marbled Murrelet

TRU Environmental Sciences Seminar

January 20, 2011 3:30-4:30

Alan E. Burger

Department of Biology, University of Victoria

"Managing a threatened species with widely differing foraging and nesting habitats: The importance of understanding population limitation in Marbled Murrelets".

Image from: www.sierraclub.bc.ca/endangered-species

Dr. Alan Burger has studied the marbled murrelet (Brachyramphus marmoratu) for 20 years but says he still has a lot to learn. The distribution of this sea bird encompasses Alaska and the North American pacific coast where they spend roughly 80% of their life foraging underwater in near shore habitat and 20% nesting on mossy platforms of old-growth conifers.

According to Burger, copious amount of research on habitat parameters has been carried out and results show forest age, tree height and distance from ocean to be of importance. Roughly 1/3 of nestlings fledge and predation is the primary cause of nest failure. Despite the parents best attempts at hiding their offspring, predators such as crows, steller’s jays, squirrels and mice effectively stumble across eggs and young chicks. Marbled murrelets are long-lived and this coupled with low reproduction rates equates a low population turnover.



So why is the marble murrelet threatened? A closer look into marine and/or terrestrial factors limiting population size may be the answer. Burger discussed that at sea the limiting factor in population growth is prey availability while on land it’s nesting habitat, predation and social factors. The evidence is contradictory. Research from South West Vancouver Island, such as at-sea-counts and juvenile recruitment, illustrates marine factors to effect populations in the short-term. Radar counts at watersheds tracked low variability across years but high spatial changes amongst sites. In California there is a sink population (reproductive output is inadequate to maintain the local population levels) and prey availability effects breeding in some years.  However, there is immigration so food cannot be limiting. Watersheds where logging occurred showed a decrease in population size while the opposite was seen with intact forests. In Alaska, where terrestrial studies are lacking, researchers blame prey scarcity.  

Population loss is linked to logging, especially in BC and USA, says Burger. However, if we look at habitat availability, present data shows about 10-200 trees with platforms ha^-1 and an average of 1 nest per 33ha. It is not the trees with platforms that are limiting. Why then is the population struggling? An explanation:  The birds want to be spaced out. Flight and vocalization could be presented as spacing behaviour to reduce chances of a predator locating the nest. Further studies on social behaviour of these birds (although an unusual parameter in forest management) may be the key to understanding population decline of the marbled murrelet.   

My opinion:  A great lecture filled with valuable information. But we have much to learn. It’s interesting to see an example where the species’ niche is not the direct limiting factor in population reduction. A situation where the assumption of habitat loss is not to blame and there is a deeper-seeded issue to decipher.

Word Count: 453

When Populations Are Too Healthy...

Mech, D. 2010. Considerations for Developing Wolf Harvesting Regulations in The Contiguous United States. Journal of Wildlife Management. 74:1421-1424.

Link to Article:

http://www.swetswise.com.ezproxy.tru.ca/FullTextProxy/swproxy?url=http%3A%2F%2Fwww.wildlifejournals.org%2Farchive%2F0022-541X%2F74%2F7%2Fpdf%2Fi0022-541X-74-7-1421.pdf&ts=1295291936003&cs=66506344&userName=5786541.ipdirect&emCondId=5786541&articleID=154167520&yevoID=3155513&titleID=116602&referer=4&remoteAddr=192.146.156.172&hostType=PRO&swsSessionId=56eaBqrIySZGe0QuskFdBA__.pasc1

Mech (2010) discusses the likelihood of a permanent harvesting season of gray wolves (Canis Lupus) in the contiguous United States within the next few years. He comments that since being placed on the United States Endangered Species List since 1967 and Endangered Species Act in 1973 gray wolf populations have successfully recovered and continue to increase in population size. Harvesting wolves is a sensitive topic and Mech (2010) explains the species has been delisted twice and relisted due to technical legal issues.

The act of hunting, trapping, and harvesting of wolves is an extremely controversial topic with the general public in addition to ranchers, outfitters, sportsmen, animal welfare advocates amongst others. A large number of public citizens find it hard to believe and are dismayed that it may become legal to trap or kill wolves.

I understand Mech (2010) to be accurate in stating this “divided opinion” of taking wolves makes it crucial for each state to strategically develop proper fair-chase wolf harvesting regulations. Decision making must take into account the desired harvest objectives (for hunters as well as conservation goals) in addition to meeting public acceptance.

Further, Mech (2010) explains the difficulties of harvesting many wolves and the challenges with fair-chase hunting. Tactics such as aerial shooting, tracking by snowmobile, and/or spotting by helicopter and landing to shoot are opposed by much of the public. Trapping and snaring are techniques accepted by some wolf advocates but is expensive, time-consuming, and difficult. There are also other means of control mentioned in the article.

Considering the continuously growing populations of gray wolves there is a strong probability of harvesting management being put forth in the United States. Although it is difficult to convince the public that wolf harvesting is necessary, it may be possible to decrease people’s opposition by setting restrictions such as not killing individuals readily identifiable as pups or gravid females.

This topic is exceedingly sensitive and as someone who is keen on wolves, understands biological conservation, and an open-minded individual I understand both ends of the problem. Essentially, the best case scenario for the wolf is that humans all disappeared – or at least stopped growing exponentially – and the rancher’s would probably prefer the wolves didn’t exist at all. I think Mech successfully achieved an unbiased standpoint and considered both sides of the issue and it appears he agrees that the regulated ‘culling’ of gray wolves in the near future is essential for successful management of the species. The question is: How does one convince the public that shooting a cute fluffy animal is the ‘right thing to do’?

Word Count: 430