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assemblage of cave and surface species of crayfish for which credible age estimate exist, suggesting that a cave environment per se is not required for the evolution of extreme longevity in crayfish. Introduction A select group of aquatic animals exhibit remarkable longevity. The ocean quahog clam (Arctica islandica [L.]), for example, has been reported to live for more than 400 years (Wanamaker et al., 2008), while marine tubeworms surrounding hydrocarbon seeps can live for over 200 years (Bergquiest et al., 2000). Among vertebrates, several species of deep-sea fishes have life spans in excess of 100 years (see Koslow et al., 2000; Finch, 2009). Such “centenarian taxa” have long been of interest to biologists because they represent an extreme end point on the life history continuum and provide insights into the physiological processes (e.g. genome maintenance and reduced oxidative stress) that produce exceptionally long life spans (Bodnar, 2009; Voituron et al., 2011). Not surprisingly, the population dynamics of such long-lived species also pose unique challenges for management and conservation. Among freshwater taxa, cave-adapted organisms offer some excellent examples of extreme longevity. In cave ecosystems, resources are limited due to the absence of light, which prevents primary production (except in chemolithoautotrophy-based systems; Engel et al., 2004), and by reduced surface connectivity, which limits inputs of allochthonous organic matter (Poulson & Lavoie, 2001). In response, many obligate cave species have evolved K-selected life history characteristics, such as long life span, slow growth rate and reduced fecundity (Hüppop, 2001). One frequently reported example of longevity in a cave organism is the extreme life span estimated for the obligate cave crayfish Orconectes australis (Rhoades). Cooper (1975) used a mark-recapture approach to study the population size, age structure,and growth of O. australis in Shelta Cave, Alabama, USA. Using models based on growth rates from free-roaming 75
individuals, he predicted that it would take 37 to 176 years for O. australis to reach a carapace length of 47 mm. Using Cooper’s (1975) data, Culver (1982) further estimated female time-tomaturity to range from 16 to 35 years, while female age-at-first-reproduction was predicted to range from 29 to 105 years. Given the astonishing longevity suggested by his data, Cooper (1975; p. 314) expressed some doubts about his analytical approach, stating “This apparently extraordinary finding requires further comment. Two alternative approaches are open: (1) consideration of factors which could actually confer “immortality” on these populations, and (2) further search for the flies which are undoubtedly lurking in the ointment of growth records (based on carapace lengths) and rates inferred from them.” Despite this plea for caution, these longevity estimates have been referred to in comparative life history studies (Hobbs, Hobbs & Daniel, 1977; Weingartner, 1977; Streever, 1996; Cooper & Cooper, 2004; Vogt, 2012) and toxicology studies (Dickson, Briese & Giesy, 1979). References to these estimates can also be found in books, popular magazines, journal newsletters and websites which discuss life history evolution in cave species, cave conservation issues, and the uniqueness of cave ecosystems (Culver, 1982; Anonymous, 1999; Hüppop, 2001; Krajick, 2001; Poulson & Lavoie, 2001; Culver, 2005; Krajick, 2007; web search: Orconectes australis life span; 100 year-old cave crayfish, 17 July 2011). If Cooper’s (1975) models are correct, O. australis belongs to a small group of animals known to have 100+-year life spans (see Ziuganov et al., 2000; Finch, 2009). However, extraordinary life span estimates must be informed by extraordinary data. In light of Cooper’s (1975) uncertainties regarding his longevity models, this study sought to reevaluate the life history of O. australis. Access to Shelta Cave is now restricted and the site has also been affected 76
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THE INFLUENCE OF ENERGY AVAILABILIT
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ABSTRACT Detritus from surface envi
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LIST OF ABBREVIATIONS AND SYMBOLS m
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NC IL ON U.K. VIAT VIE Fig. North C
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AIC K-S Akaike information criterio
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laboratory work and was an excellen
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LIST OF TABLES TABLE 2.1 TABLE 2.2
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LIST OF FIGURES FIGURE 2.1 (a) Box
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FIGURE 4.3 Growth models for Orcone
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chemolithoautotrophy-based systems;
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ecology, 51, 31-53. Gibert J. & Cul
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CHAPTER 2 EFFECTS OF ORGANIC MATTER
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community structure in cave “pits
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communities and how variation in co
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the different source locations was
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of natural-log transformed data (%
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peak in organic matter in Big Mouth
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Figs. 5a, b). The breakdown rate of
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per litter bag. Similarly, Huntsman
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ags was the greater retention of li
Page 41 and 42: Historically, limited resource inpu
Page 43 and 44: Culver, D.C. & Pipan, T. (2009) The
Page 45 and 46: Merritt, R.W., Cummins, K.W. & Berg
Page 47 and 48: Table 1. Mean (1 S.D.) macroinverte
Page 49 and 50: Table 2. Mean (±1 S.D.) daily temp
Page 51 and 52: Figure 1. (a) Box and whisker plot
Page 53 and 54: Figure 3. Non-metric multidimension
Page 55 and 56: Figure 5. Box and whisker plot of l
Page 57 and 58: streams, while the obligate-cave sp
Page 59 and 60: More recent observational and exper
Page 61 and 62: of netting (mesh size 2.5×1.5-cm)
Page 63 and 64: the two end-members. This conservat
Page 65 and 66: crop organic matter significantly i
Page 67 and 68: macroinvertebrate biomass to levels
Page 69 and 70: and surface streams (20-35,000 g m
Page 71 and 72: these factors, the stable isotope a
Page 73 and 74: surface streams. Thus, it is likely
Page 75 and 76: subsides to ecosystem dynamics have
Page 77 and 78: populations. Journal of Applied Eco
Page 79 and 80: Poulson T.L. & Lavoie K.H. (2001) T
Page 81 and 82: Wood P., Gunn J. & Perkins J. (2002
Page 83 and 84: Table 2. Mean (±1 standard deviati
Page 85 and 86: Table 2. Continued Chironomini Para
Page 87 and 88: Figure 1. Mean (bars are standard e
Page 89 and 90: Figure 3. Non-metric multidimension
Page 91: CHAPTER 4 REXAMINING EXTREME LONGEI
Page 95 and 96: A phylogeographic study by Buhay &
Page 97 and 98: differences in size structure among
Page 99 and 100: and females in Tony Sinks Cave were
Page 101 and 102: Estimates of life span for O. austr
Page 103 and 104: available size-classes were well re
Page 105 and 106: References Anonymous (1999) Cave Sc
Page 107 and 108: Huryn A.D. & Wallace J.B. (1987) Pr
Page 109 and 110: Whitmore N. & Huryn A.D. (1999) Lif
Page 111 and 112: Table 2. Estimated life span (years
Page 113 and 114: Figure 1. Annual growth increment (
Page 115 and 116: Figure 3. Growth models for Orconec
Page 117 and 118: CHAPTER 5 CONSUMER-RESOURCE DYNAMIC
Page 119 and 120: following incidental inputs of orga
Page 121 and 122: Temperature data were not available
Page 123 and 124: minimum (Venarsky et al., 2012b). A
Page 125 and 126: 100% organic matter (i.e., maximum
Page 127 and 128: Macroinvertebrate biomass varied si
Page 129 and 130: Discussion The energy-limitation hy
Page 131 and 132: crayfish captured in most months we
Page 133 and 134: systems is likely high, especially
Page 135 and 136: function of microbial films in grou
Page 137 and 138: Crustacean Biology, 4, 35-54. Momot
Page 139 and 140: Whitmore N. & Huryn A. (1999) Life
Page 141 and 142: Table 2. Assimilation efficiencies
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Table 3. Continued Tanypodinae 0.03
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Table 5. Estimates of mean wood and
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Figure 1. (A) Box and whisker plot
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CHAPTER 6 OVERALL CONCLUSIONS Due t
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characteristics (e.g., higher growt
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characteristics, highly efficient p
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