Lecture10_PopulationsB

Lecture10_PopulationsB - Last Time: Darwin: Evolution /...

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Unformatted text preview: Last Time: Darwin: Evolution / Revolution exhibit at the San Diego Natural History Museum Population descriptors 1. Density ✓ 2. Dispersion ✓ 3. Demography ✓ Fig. 53-6 • • Free admission and bus transportation for BILD 3 students Saturday Nov. 14 Faculty from science, history, theology, and philosophy will be on hand to answer questions Number of survivors (log scale) 1,000 I Schedule: 2:30 PM !!!!!!!!!Arrival at Museum 2:30 - 3:30 !!!!!Exhibition Experience 3:30 - 3:45 !!!!!Transition to Theater 3:45 - 5:00 !!!!!Theater Presentations & Discussion 5:15 - 6:15 !!!!!Atrium Coffee House • • • • Age Structure Life Tables Survivorship Curves Life History Traits 100 II 10 III 1 0 50 Percentage of maximum life span 100 4. Dynamics • Please RSVP to Brandy Misquez (bmisquez@ucsd.edu) by Friday Nov. 6 1 Tuesday, November 3, 2009 2 Tuesday, November 3, 2009 CQ Elephants in Zoos Elephants in Zoos • Working with your neighbors • - Compare your survivorship curves. What are the main differences between them? elephants? What type of survivorship curve did the elephant groups resemble? !###" +,-./0"12"311"45/6789:;" +,-./0"12"<=5>"45/6789:;" A. Curve I !##" !"#$%&'&(%)" - What factors could explain the pattern observed in zoo - Are there any problems with the data? B. Curve II C. Curve III !#" !" • • Tuesday, November 3, 2009 3 #" !#" $#" %#" &#" *+," '#" (#" )#" *#" Why might elephants have reduced survivorship in zoos? Are there any problems with this data? Tuesday, November 3, 2009 4 What are the limits to population growth? Objectives 1. Describe population growth using conceptual and mathematical models 2. Use mathematical population models to predict future population sizes 3. Apply population growth data to management decisions 4. Understand factors regulating population growth 4. Dynamics • • • How populations grow and change over time What factors influence how populations grow? - births, immigration - deaths, emigration What might limit population growth? Tuesday, November 3, 2009 5 Tuesday, November 3, 2009 6 How do populations change over time? Births (+) Immigration (+) What is this? A positive feedback loop: The more are born, the more can reproduce... Emigration (-) How do populations change over time? Population(t+1) = Population(t) + births - deaths + immigration - emigration Nt+1 = Nt + B - D + I - E Population size • Deaths (-) Nt+1 = Nt (b - d) - b, d = per capita (per individual) births, deaths - Ex. b = # births / total # individuals 1 birth in a population of 10 ! b = 0.1 Ignore these to simplify In your notebook: N is the size of a population at time t. How would you represent (in words) the size of this population at a future time (t+1)? Tuesday, November 3, 2009 7 Tuesday, November 3, 2009 8 How do populations change over time? Population(t+1) = Population(t) + births - deaths + immigration - emigration How do populations change over time? Nt+1 = Nt r This equation considers change in population size from t to t+1 To represent any time interval, ∆N = N r ∆t Using calculus, we can re-write to represent instantaneous population growth rate dN = N r dt Nt+1 = Nt + B - D + I - E Nt+1 = Nt (b - d) Ignore these to simplify We can rewrite this as Nt+1 = Nt r r = per capita rate of increase (growth rate) r=b-d Tuesday, November 3, 2009 9 Tuesday, November 3, 2009 10 How do populations change over time? dN/dt = N r r=b-d Exponential Growth dN/dt = N r Fig. 53-10 Population size (N) • r>0 r<0 r=0 With your neighbor : • 2,000 dN = 1.0N dt What does this look like? - Ex. Start with N = 10, r = 0.5 - What if r = 1? 1,500 dN = 0.5N dt - Describe the growth rate, r, if the population next year increases. - Describe the growth rate, r, if the population next year decreases - Describe the growth rate, r, if the pop next year doesn’t change 1,000 • • • Exponential curve r does not change over time, but population size does Resources are unlimited (rmax) 500 0 0 5 10 Number of generations 15 Tuesday, November 3, 2009 11 Tuesday, November 3, 2009 12 CQ Exponential Growth 1272 W. D. Bowen et al. through the 1990s (Petrie and Drinkwater, 1993; Drinkwater et al., 1998). Continuous plankton recorder data of phytoplankton colour index, diatoms, and Calanus sp. show significant decadal scale changes between 1961 and 1998 (Sameoto, 2001). The influx of Arctic species is consistent with the colder waters during the 1990s. In addition, a major shift in the phytoplankton production cycle to the earlier months appears to have taken place, with corresponding changes in peak diatom abundance. Although changes at lower trophic levels are not expected to directly affect grey seal dynamics, bottom-up effects on prey might influence foraging success and hence reproduction and survival. Grey seals consume a variety of small pelagics, flatfishes, and gadoids (Bowen et al., 1993; Bowen and Harrison, 1994). Biomass of demersal fishes on the Scotian Shelf showed a stable to slightly increasing trend through the mid-1980s, but declined precipitously from the mid-1980s to the lowest value observed in the past 30 years. On the eastern shelf, biomass declined by 80% (Zwanenburg et al., 2002). Roughly coincident with marked declines in Atlantic cod (Gadus morhua) biomass and colder temperatures on the eastern shelf was a sharp increase in capelin (Mallotus villosus) and sandlance (Ammodytes dubius) abundance during the late 1980s and through the 1990s (Zwanenburg et al., 2002). Overall, the estimated total fish biomass increased through the 1990s and the average size of demersal fishes declined. InTuesday, November 3, 2009 vertebrate abundance also changed with significant increases in snow crab (Chionocetes opilio) and shrimp (Pandalus borealis) over the same period (Zwanenburg et al., 2002). In the face of these major marine ecosystem changes, the rate of increase in pup production has remained apparently unaffected. This suggests that both survival and reproductive rates were insensitive to environmental and fishery induced changes. Elsewhere, evidence exists for the effects of environmental variability on the population dynamics of pinnipeds. For example, the collapse of the capelin stock in the Barents Sea in 1985/1987 has been linked to large-scale invasions of harp seals (Phoca groenlandica) along the Norwegian coast in 1987. Capelin are an important prey species for the harp seal population, making up more than 90% of the diet in some years. Many of the seals caught in the coastal gillnet fishery were thin and in poor condition (Haug and Nilssen, 1995). Presumably as a result of this large-scale mortality of young seals, the 1986e1988 cohorts were nearly absent (Kjellqwist et al., 1995). Long-term changes in the availability of krill (Euphausia superba) have strongly influenced the dynamics of upper trophic-level pinniped and seabird predators in the region of the Antarctic Peninsula (Reid and Croxall, 2001). In both examples above, predators were dependent largely on a single prey for which a suitable substitution was not available. By contrast, grey seals on the Scotian Shelf are not so dependent on individual prey species (Benoit and Bowen, 1990; Bowen et al., 1993) enabling Grey Seals the number of grey seals has occurred in the face of considerable environmental change. Long-term environmental variability of the Scotian Shelf, the marine ecosystem primarily used by grey seals from Sable Island, is summarized in Zwanenburg et al. (2002). Interannual variability in water temperature and salinity in this area is among the highest observed in the North Atlantic. On the northeastern Scotian Shelf, the cold intermediate layer water oscillated near or above the long-term mean during the 1960s and 1970s, rose above normal in the early 1980s, fell sharply by the mid-1980s and remained below normal • Where do we see exponential growth in nature? Table 8. Estimate of grey seal pup production on Sable Island in 1997. Total • • Case study: Grey seals in Canada East colony after - Colonization of new habitat or recoveryWest colonycatastrophe - Hunted to near extinction - Detailed population monitoring on Sable Island since 1960s - Pulse of new nutrients (eutrophication) - Introduced species (new niche) Pup counts from 3359 17 504 20 863 positives Proportion born 0.66 G 0.05 0.93 G 0.01 Ground-count 1.05 G 0.02 1.05 G 0.02 correction Corrected 5318 19 626 24 944 production Dead pups 73 382 455 Total pup 5391 20 008 25 400a production 95% CI 4469e6676 19 046e20 219 23 500e26 900a a Was this population growing exponentially in 1980-2000? Figure 3. Trend in grey seal pup production on Sable Island, 1962e1997, based on incomplete tagging (1962e1974), complete tagging (1976e1990) and aerial surveys (1989e1997) (error bars: approximate 95% confidence limits; curve: exponential fit to the 1976 through 1990 censuses, see text for equation). Rounded to the nearest hundred. A. Yes B. No Tuesday, November 3, 2009 Exponential Growth Island and along the coast of eastern Canada and northeastern United States is still plentiful, food is more likely to regulate grey seal numbers at some stage, consistent with the general view that most large mammals are regulated by food supply (Sinclair, 1996). However, it is not possible with current information on prey abundance to forecast when food might become limiting. An interesting feature is that the continued increase in the number of grey seals has occurred in the face of 13 considerable environmental change. Long-term environmental variability of the Scotian Shelf, the marine ecosystem primarily used by grey seals from Sable Island, is summarized in Zwanenburg et al. (2002). Interannual variability in water temperature and salinity in this area is among the highest observed in the North Atlantic. On the northeastern Scotian Shelf, the cold intermediate layer water oscillated near or above the long-term mean during the 1960s and 1970s, rose above normal in the early 1980s, fell sharply by the mid-1980s and remained below normal and the av vertebrate creases in (Pandalus et al., 2002 In the fac rate of incre unaffected. tive rates w induced cha of environm pinnipeds. F the Barents invasions o Norwegian species for 90% of the the coastal (Haug and large-scale cohorts we Long-term superba) ha trophic-leve the Antarcti In both largely on was not av Shelf are n (Benoit and 2284 M. KURTIS TRZCINSKI ET AL. 14 Grey Seals • • Is exponential growth realistic? • 2005 survey shows a change in the population growth exponential growth Is it sustainable? - Dotted line is model of With your neighbor: What factors could have led the seal growth curve to level off? • Figure 3. Trend in grey seal pup production on Sable Island, 1962e1997, based on incomplete tagging (1962e1974), complete tagging (1976e1990) and aerial surveys (1989e1997) (error bars: approximate 95% confidence limits; curve: exponential fit to the 1976 through 1990 censuses, see text for equation). Tuesday, November 3, 2009 15 Tuesday, November 3, 2009 seasonal movement steady rise in the nu area from fewer tha 158 750 seals (67186 was also a strong sea 2003 varied from abo winter (Fig. 7). Fig. 8a shows the from four-survey s 2284 M. KURTIS TRZCINSKI ) numbers sho morhuaET AL. 1980s. Spawning sto Current movement seasonal estimates fo lowest in in entire steady rise thethe nu closure of fewer tha area from the fishery 158 750 seals (67186 rates thereafter (Fig was also of strong sea biomass a 6524 t (1 2003 varied fromare overall trends abo winter (Fig. 7). reported in perviou Fig. 8a shows the Fanning et al. 2003) fromfallen more ra has four-survey s morhua) numbers sho indicating a change 1980s. Spawningand cod population, sto Current estimates fo the dwindling stock b lowest in the entire (Fig. 8b). FIG. 5. (a) Census counts (circles) and model fit (solid line) closure energetics m The of the fishery to the pup production of the Sable Island gray seal population. rates thereafter 1.61 males consumed (Fig In early years, only partial censuses (plus symbols) were per year (Table t (1 completed. These data were added to the plot for reference biomass of 65243). Y of the trends pop but were not fit to by the model. The model of exponential overall gray sealare increases (dotted line) was not used but was added for reported consumed size, they in perviou comparison. (b) Model estimates of total population size. Fanning et al. 2003). Total consumption v Vertical lines indicate the 95% CI. has classes more ra sex fallen showed indicating a change Consumption by you variances from the Hessian matrix are carried through cod total, was highes the population, and the model and are reflected as uncertainty in the final the dwindling stock b third and fourth estimates of consumption. Consequently, a large (Fig. 8b). fairly cons males was FIG. 5. amount of(a) Census counts (circles) incorporated(solid line) then increased in the variability has been and model fit into the The energetics m to the from a wide variety of sources. This variability modelpup production of the Sable Island gray seal population. males consumed 1.61 by adult females was In early years, only partial censuses (plus symbols) were can be broadly categorizedadded uncertainty for gray seal per year (Table low Y into to the plot in reference reproduction), 3). i completed. These data were (1) population to by the model. energetics, of exponential of the gray seal pop but were not fit dynamics, (2) The model and (3) cod 16 highest in the fourth increases (dotted line) was not used but was added for consumption. Several sources of error were not includ- size, by adult males tion they consumed comparison. model component contains a few fixed values (b) Model estimates of total population size. ed, as each Total consumptionra was caused by the v Vertical lines indicate the 95% CI. (Table 1, Appendix). Variability in the cod model was sex classestoshowed leading up the bre incorporated by running the seal model at 61 SE of cod Consumption by you Factors limiting population growth Factors limiting population growth • • Density-independent: Affect a population independent of its density Density-dependent: Birth and/or death rates change with population density • Density-dependent - Competition for Resources Predation Wastes Intrinsic Factors • • Tuesday, November 3, 2009 17 Density-independent - Climate/weather - Catastrophic events Some factors can fall into both categories - Disease - Climate/weather Tuesday, November 3, 2009 18 Population growth in a limited environment Growth in a limited environment dN = N r dt • Can we make our equation more realistic in an environment with limited resources? Un-utilized dN = N r dt () K-N K opportunity for population growth () K-N K • What might this growth curve look like? K = carrying capacity, maximum # individuals the environment can support • Imagine what happens to the equation if the population size is close to the carrying capacity, K. If N is much larger? Smaller? Tuesday, November 3, 2009 19 Tuesday, November 3, 2009 20 2284 M. KURTIS TRZCINSKI ET AL. Logistic Growth • • • Sigmoid or logistic growth curve Where is K? Density-dependence K Population size (N) 2,000 Exponential growth 1,500 1,000 Logistic growth - growth rate (r) changes with population size 500 0 0 5 10 Number of generations 15 Tuesday, November 3, 2009 21 Logistic Growth • • A model of population growth Several assumptions: Population size (N) 2,000 Exponential growth - No immigration or emigration - No time lags - K is constant 1,500 1,000 Logistic growth 500 0 0 5 10 Number of generations 15 Tuesday, November 3, 2009 23 seasonal movement pa steady rise in the numb area from fewer than 8 158 750 seals (67186 SE was also a strong seaso 2003 varied from about winter (Fig. 7). Fig. 8a shows the fit from four-survey ser 2284 M. KURTIS TRZCINSKI ET AL. morhua) numbers show 1980s. Spawning stock seasonal estimates forpa Current movement e steady rise thethe numb lowest in in entire 3 area from the fishery in closure of fewer than 8 158 750 seals (67186 SE) rates thereafter (Fig. was also of strongt seaso biomass a 6524 (1 SE 2003 varied fromare in overall trends about winter (Fig. 7). reported in pervious Fig. 8a shows the S Fanning et al. 2003).fit from fallen more rapid has four-survey seri morhua) numbers show indicating a change in 1980s. Spawningand re cod population, stock Current estimates for ei the dwindling stock bec lowest in the entire 3 (Fig. 8b). FIG. 5. (a) Census counts (circles) and model fit (solid line) closure of the fishery in The energetics mod to the pup production of the Sable Island gray seal population. rates thereafter 1.61 to males consumed (Fig. In early years, only partial censuses (plus symbols) were per year (Table t (1 SE: completed. These data were added to the plot for reference biomass of 6524 3). You of the trends popul but were not fit to by the model. The model of exponential overall gray sealare in increases (dotted line) was not used but was added for reported in pervious 1 size, they consumed ; comparison. (b) Model estimates of total population size. Fanning et al. 2003). Si Total consumption vari Vertical lines indicate the 95% CI. has classes more rapid sex fallen showed c indicating a change in t Consumption by young Tuesday, November 3, 2009 22 variances from the Hessian matrix are carried through cod total, was highest i the population, and res the model and are reflected as uncertainty in the final the dwindling stock beco third and fourth q estimates of consumption. Consequently, a large (Fig. 8b). fairly consist males was amount of variability has(circles) incorporated(solid line) then increased in the la FIG. 5. (a) Census counts been and model fit into the The energetics mod to the from a wide variety of sources. This variability modelpup production of the Sable Island gray seal population. males consumed 1.61 to by adult females was hi In canearly years, categorized into uncertainty in gray were per year (Table lowYou be broadly only partial censuses (plus symbols) seal reproduction), 3). in completed. These data were added to the plot for reference (1) population to by the model. energetics, of exponential of the gray seal popula but were not fit dynamics, (2) The model and (3) cod highest in the fourth qu consumption. Several sources of error were not includ- size, they consumed ;1 increases (dotted line) was not used but was added for tion by adult males an comparison. (b) Model estimates of total population size. ed, as each model component contains a few fixed values Total consumptionrapid was caused by the vari Vertical lines indicate the 95% CI. (Table 1, Appendix). Variability in the cod model was sex classes to the breed leading up showed co incorporated by running the seal model at 61 SE of cod Consumptionassumptio Under the by young variances from the Hessian matrix range in through model estimated that 2 numbers at-age. We present the are carriedmortality the total, was highest in the model and seal predation uncertainty in the estimates due toare reflected as and other sources. final the third and seals in 20 consumed by fourth q estimates of consumption. Consequently, a large malesof 5369 (69519 SE mass was fairly consiste RESULTS amount of variability has been incorporated into the then increased in the mo functional-response las model from a (Halichoerus of sources. This variability by) adult females was hi Gray seal wide variety grypus) populations have SE million cod were can be broadly categorized into uncertainty in gray seal corresponding to in s continued to increase on Sable Island, but the 2004 reproduction), low 2899 (1) population dynamics, (2) energetics, and in cod functional-response m estimate suggests that the rate of increase (3) pup highest in the fourth qu consumption. Several sources 5). In were not of St. consumed 97 males an production Immigration & emigration has slowed (Fig. of error the Gulf includ- tion by adult cod (i.e., ed, as each model component contains a over time, with at ages 1–5, respectively Lawrence, pup production also increasedfew fixed values was caused by the rapid (Table 1, Appendix). Variability in the cod model and the 2004 estimate the highest in the series (Hammill was leading up 1995, the ins Prior to to Carrying capacity (K) is 2005; Fig. 6). the seal model capacity of cod (ages 1–5) duethe breed incorporated by running The carrying at 61 SE of the Gosselin Under the assumption to seal p numbers at-age. We present the range 430 000 gray than 0.01. Seal predatio Sable Island population was estimated at in mortality model estimated that 2 rarely constant estimates due to seal predation and other sources. seals, with the density-dependent parameter, h, held consumed by seals in 20 seal population grew a 80 constant at 2.4 (Trzcinski et al. 2005). Combining mass of 5369 (69519 SE) declined. The functiona RESULTS Time lags occur estimates of total population size with estimates of functional-response mo predation mortality to 60 Gray seal (Halichoerus grypus) populations have SE) million cod were continued to increase on Sable Island, but the 2004 corresponding to 2899 Environment changes 40 estimate suggests that the rate of increase in pup functional-response mo production has slowed (Fig. 5). In the Gulf of St. consumed 97 cod (i.e., 20 Lawrence, pup production also increased over time, with at ages 1–5, respectively the 2004 estimate the highest in the series (Hammill and Prior to 1995, the ins 0 Gosselin 2005; Fig.1975 The carrying 1capacity of 2000 (ages 1–5) due to seal p 6). 1980 1985 990 1995 the Sable Island population was Time (years) at 430 000 gray than 0.01. Seal predatio estimated seals, with the density-dependent parameter, h, held seal population grew a (c) A song sparrow pet al. 2005).natural habitat. opulation in its Combining constant at 2.4 (Trzcinski declined. The functiona The population of female song sparrows nesting on Tuesday, November 3, 2009 2 estimates of total population size with is periodically of predation4mortality to a Mandarte Island, British Columbia, estimates Grey Seals Revisited • Which model of population growth (exponential or logistic) best fits the grey seal data? Do we see logistic growth in nature? • • Not often. Why? Assumptions are too simplistic - Figure 52.13c Number of females reduced by severe winter weather, and population growth is not well described by the logistic model. What about humans? 7 Human population (billions) What about humans? 2.2 2.0 1.8 6 5 4 3 The Plague • What kind of • Annual percent increase growth does this curve represent? Is this growth sustainable? humans? • What kind of 2005 Projected data growth does this curve represent? sustainable? humans? 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 1950 1975 2000 Year 2025 2050 • Is this growth • What is K for 2 1 0 • What is K for 8000 B.C.E. 4000 3000 2000 1000 B.C.E. B.C.E. B.C.E. B.C.E. 0 1000 C.E. 2000 C.E. http://www.census.gov/main/www/popclock.html Tuesday, November 3, 2009 25 Tuesday, November 3, 2009 26 Human Population Growth Mountain Yellow-Legged Frogs • Ecological Footprint: Measure of human demand on Earth’s ecosystems http://earthday.net/footprint/index.html • • Assignment: Food webs for endangered mountain yellow-legged frogs Posted on WebCT, Due in lecture 11/5 Tuesday, November 3, 2009 27 Tuesday, November 3, 2009 28 CQ Elephants in Captivity • A. This population will decrease over time B. This population will increase over time C. This population has an equal number of births and deaths Tuesday, November 3, 2009 Survivorship Survivorship Survivorship The authors of the study calculated population growth rate, r, for elephants in the wild to be 1. Based on this, which of the following statements is TRUE: wild-born females was about 3.4 years, this sugge that zoo-born Asians’ elevated adult mortality ris are conferred during gestation or early infancy. Interzoo transfers also reduced Asian survivo ship (see supporting online text), an effect lasting years posttransfer (z = –2.10, P < 0.05, contro ling for birth origin). Additionally, survivorsh Ros Clubb,1 Marcus Rowcliffe,2 Phyllis Lee,3,4 Khyne U. Mar,2,5 Cynthia Moss,4 Georgia J. Mason6* P < 0.001). Because the median importatio tended to be poorer in Asian calves removed fro wild-born females waszabout 3.4 years, this mothers at young ages ( = –1.92, P < 0.10) (5 zoo-born Asians’ elevated zoos morta ild animals can experience poor welfare (over double those of M.T.E.): A female’s first preg- that Overall, bringing elephants into adultprofoun ly conferred during gestation or of early e when held captive (1), an effect with eth- nancy therefore had only a 42% chance of yielding a are impairs their viability. The effectsearly infa ical and practical implications. In zoos, live year-old in zoos compared with 83% in M.T.E. perience, interzoo transfer, and possibly matern Interzoo transfers also reduced Asian s With your neighbor: loss, plus the health and reprodu the welfare of African elephants ship (see supporting onlinerecorded ineffect text), an zoo e 1 tive (Loxodonta africana) and Asian A Compare the effects of captivity on1 juvenile AsianyearsC African problems (2)], suggest stre andposttransfer (z [e.g.,2.10, P < 0.05, phants = – elephants (Elephas maximus) has ling for birth origin). Additionally, surv and/or obesity as likely causes long caused concern. Infanticide, elephants. Ros Clubb,1 Marcus Rowcliffe,2 Phyllis Lee,3,4 Khyne U. Mar,2,5 Cynthia Moss,4 Georgia J. Mason6* Herpes, tuberculosis, lameness, intended to be Does survivorship of Asian elephants still resemble a Type poorer in Asianand Notesremov I References calves fertility, and stereotypic behavior mothers at young R. Clubb,z = –1.92, P 4250. ages ( G. Mason, Nature < , 4 1. are prevalent (2), and zoo elephant survivorship curve? Overall, bringing elephants into zoos p ild animals can experience poor welfare (over double those of M.T.E.): A female’s first preg(2003). populations are not self-sustaining viability. The effects of nancy therefore in captivity vs. the wild a ly when held captive (1), an3). How does being born had only a 42% chance of yielding affectimpairs their 2. R. Clubb, G. Mason, A Reviewof te without importation ( effect with ethWe comWelfare of Zoo Elephants in Europ 0.5 transfer, and possibly live ical and practical implications. In zoos, 0.5 year-old in zoos compared with 83% in M.T.E. perience, interzoo (RSPCA, Horsham, UK, 2002). piled data from over 4500 urvivorship? individs 1 3 5 7 9 1 3 5 7 9 3. M. Hutchins, M. health and r2 loss, plus the Keele, Zoo Biol. the welfare of African elephants uals to compare survivorship in 219 (2006). 1 zoos and Asian tive problems recorded in (Loxodonta africana) with protected populations 1 4. European Elephant Group, D A B1 1 C in maximus) has “Elefanten in zoos und sugge phants [e.g., (2)],safariparks elephants (Elephas range countries. Data representEuropa” (European Elephant Grou ing about half the global zoo popand/or obesity as likely c long caused concern. Infanticide, came from Grünwald, Germany, 2002). ulation (1960 to 2005) 5. Methods and supplementary resul Herpes, tuberculosis, lameness, in- ” and the EuEuropean “studbooks are available as supporting mater References and Notes fertility, and stereotypic Elephant Group (4). We ropean behavior on Science Online. focused elephant 6. 1. R. Clubb, the Mason, Science G.J.M. thanks G. Natural Natur are prevalent (2), and zooon females as relevant to and(2003). Engineering Research Council population viability populations are not self-sustaining(N = 786, both 0 2. R. Clubb, G. Mason, AR.Rev funding; R.C. and G.J.M. thank Rip 0 wild-caught and captive-born; 302 African Elephants Asian 30 50 70 Elephants without importation (3). We com10 for statistical advice; P.L. and C.M. tha 10 30 50 70 Welfare of Zoo Elephants African and 484 Asian). African 0.5 0.5 many conservation nongovernmenta (RSPCA, Horsham, UK, 20 piled data from over 4500 individelephants in Amboseli National 1 organizations and private donors for 3 5 7 9 1 5 7 9 Age 3 3. M. Hutchins, M. Keele, Zo uals to compare Park, Kenya (N =in and Asian survivorship 1089), supporting the Amboseli Elephant Tru Age 219 K.U.M. (2006). M.T.E. zoos with protected populations elephants in the Burmese logging Ref = non-zoo thanks colleagues at Groupf 1 1 captive born 4. European Elephant Zoo captive-born D Ref data compilation and comments. G.J B industry (Myanma in range countries. Data represent- Timber Enteris a“Elefanten in zoos und sa visiting professor at The Royal populations College, London, UK. K.U Zoo wild-born Ref wild born Veterinary ” (European Elepha Europa ing about half theprise, M.T.E., N = 2905, wildglobal zoo pop29 Tuesday, captive-born) acted 30 Ref wild born, natural mortality has received funding from Prospect Bur caught andNovember 3, 2009 as Grünwald, Germany, 2002 ulation (1960 to 2005) came from Foundation, Charles Wallace Burma Tr well-provisioned reference popula- Fig. 1. Kaplan-Meier survivorship curves for female African (A and B) and Asian (C and 5. Methods and supplementa Three Oaks Foundation, Whitney-Lai European “studbooks”[for details, see (2) and (5)]. tions and the Euare available Small Grants), D) elephants aged 1 to 10 [juveniles in (A) and (C)] and 10+ years [adults in (B) and (D)]. Foundation (Rufford as supportin ropean Elephant Group (4). We For African elephants, median For wild-born reference (Ref, Amboseli or M.T.E.) populations, natural mortality excludes on Science Online. Toyota Foundation, Fantham Memor Research Scholarship, andNatural life spans (excluding focused on females as relevant to premature and human-caused deaths; all mortality includes them (5). Results of statistical comparisons 6. G.J.M. thanks the University College London. K.U.M. has been a p stillN = 786, both years [95% are given in table S2. births) were 16.9 and Engineering Research population viability ( consultant for Woburn Safari Park, U 0 confidence interval (CI) funding; R.C. and G.J.M. tha 0 G.J.M. has been a paid consultant to wild-caught and captive-born; 302 16.4 to un10 30 50 for statistical advice; P.L. (table S1). Rates have not significantly improved 70 known; upper estimate for median 10 reached] for 50 not 30 70 Disney’s Animal Kingdom, USA. and African and 484 zoo-born females and 56.0 years (95% CI 51.5 to over time (e.g., live births controlling for parity: z = Asian). African many conservation nongove Supporting Online Material elephants in Amboseli National females undergoing natural 1.19, P > 0.10). ForAge captive-born survivor- www.sciencemag.org/cgi/content/full/322/5908/1649/DC1 do organizations and private juveniles, unknown) for Amboseli Park, Kenya (N = 1089), and Asian with human-induced deaths, ship did not significantly differ between populations, Materials and Methods supporting the Amboseli Ele mortality (35.9 years K.U.M. thanks colleagues at 95% CI logging elephants in the Burmese33.8 to 40.3). Neither infant nor juvenile whereas wild-born survivorship was poorer in Bur- SOM Text and S2 Tables S1 Zoo captive-born Ref captive born data compilation and comm mortality differed industry (Myanma Timber Enter-between populations (Fig. 1A ma (Fig. 1C and table S2) because of after-effects References is a visiting professor at The and tables S1 and S2), but adult females died earlier of capture (5). In adulthood, however, survivorship Zoo wild-born Ref wild born prise, M.T.E., Nin=zoos than wild2905, in Amboseli (Fig. 1B and table S2). was lower in zoos (Fig. 1D and table S2), with no 6 August 2008; accepted 22Veterinary College, London, September 2008 10.1126/science.1164298 has received funding from Pro Ref wild born, natural mortality caught and captive-born) acted as Zoo adult African survivorship has improved in re- detectable improvement in recent years (z = –1.48, Foundation, Charles Wallace B well-provisioned reference popula- P < 0.01 (5)], but mortality P > 0.10). cent years [z = –2.75, Fig. 1. Kaplan-Meier survivorship curves for female African (A and B) and Asian (C and 1 Royal Society for the Prevention of Oaks Foundation, Wh Three Cruelty to Animals (RSPC Within zoos, captive-born 10+ years poorer Wilberforce Way, risks in and (5)]. tions [for details, see (2) our data set’s final year (2005) remained [juveniles in (A) and (C)] and Asians have[adults in (B) and (D)].Southwater, Foundation RH13 9RS,SmallIn West Sussex, (Rufford UK. 2 G D) elephants aged 1 to 10 adult survivorship than 2.8 times median CI For African elephants, higher (95%For 1.2 to 6.5) than that of(Ref, Amboseli or M.T.E.) wild-born Asians (Fig. 1D tute 3of Zoology, Zoological Society of London, London NW1 4 Toyota Foundation, Fantham wild-born reference populations,origin effect: UK. Psychology Department, University of Stirling, Stirling FK9 4 natural mortality excludes and table S2). This is a birth Amboseli females 4 Research Scholarship, and U life spans (excluding premature andundergoing natural mortality.all mortality includes them (true Results of statistical comparisons for Elephants, Post Office Box 15135, Nairo human-caused deaths; 5). For Asian elephants, median life spans (exclud- Whereas zoo-born elephants are more likely to have UK. Amboseli Trust College London. K.U.M. has still births) were 16.9 years [95%stillare given in table S2. fe- been born recently and to primiparous dams, neither Kenya. 5Department of Animal and Plant Sciences, University ing premature and births) for captive-born Sheffield 2TN, UK. 6Animal Scien consultant for Woburn Safar confidence interval (CI)were 18.9un- in zoos (95% CI 17.7 to 34.0) dam parity (z = 0.86, P > 0.10) nor recency (z = –1.48, Sheffield, Western Bank,of Guelph,S10has been 2M7, Canada males 16.4 to years Department, University Guelph N1G a paid cons G.J.M. (table P Rates predict adult survivorship improved known; upper estimate foryears in the M.T.E. population (95% CI S1). > 0.10) have not significantly(controlling for *To whom correspondenceDisney’s Animal Kingdom, U and 41.7 median not reached] for should be addressed. E-m zoo-born females 38.2 to 44.6). Zoo infant mortality rates were high recencylive births origin more significant: z = –3.52, gmason@uoguelph.ca and 56.0 years (95% CI 51.5 to over time (e.g., makes birth controlling for parity: z = Compromised Survivorship in Zoo Elephants BREV Elephants in Captivity Compromised Survivorship W• in Zoo Elephants - W - unknown) for Amboseli females undergoing natural 1.19, P > 0.10). For juveniles, captive-born survivor- www.sciencemag.org/cgi/content/full/322/5908/1649 ship did not significantly differ VOL 322 12 DECEMBER 2008 mortality (35.9 years with human-induced deaths,www.sciencemag.org SCIENCE between populations, Materials and Methods 95% CI 33.8 to 40.3). Neither infant nor juvenile whereas wild-born survivorship was poorer in Bur- SOM Text mortality differed between populations (Fig. 1A ma (Fig. 1C and table S2) because of after-effects Tables S1 and S2 References and tables S1 and S2), but adult females died earlier of capture (5). In adulthood, however, survivorship in zoos than in Amboseli (Fig. 1B and table S2). was lower in zoos (Fig. 1D and table S2), with no 6 August 2008; accepted 22 September 2008 10.1126/science.1164298 Zoo adult African survivorship has improved in re- detectable improvement in recent years (z = –1.48, cent years [z = –2.75, P < 0.01 (5)], but mortality P > 0.10). 1 Royal Society for the Prevention of Cruelty to Anima Within zoos, captive-born Asians have poorer Wilberforce Way, Southwater, West Sussex, RH13 9RS risks in our data set’s final year (2005) remained 2.8 times higher (95% CI 1.2 to 6.5) than that of adult survivorship than wild-born Asians (Fig. 1D tute of Zoology, Zoological Society of London, London 3 and table S2). This is a true birth origin effect: UK. 4Psychology Department, University of Stirling, Stirlin Amboseli females undergoing natural mortality. For Asian elephants, median life spans (exclud- Whereas zoo-born elephants are more likely to have UK. Amboseli Trust for Elephants, Post Office Box 1513 Kenya. 5Department of Animal and Plant Sciences, U ing premature and still births) for captive-born fe- been born recently and to primiparous dams, neither Sheffield, Western Bank, Sheffield S10 2TN, UK. 6Anim Supporting Online Material ...
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