TITLE PAGE - acumen - The University of Alabama

More documents

Recommendations

Info

differed greatly among the four cave streams in this study, ranging from near zero to 850 g ashfree dry mass (AFDM) m -2 , which illustrates that the degree of energy-limitation can vary among cave systems within close geographic proximity. Despite the large differences in organic matter biomass, neither macroinvertebrate biomass in litter bags nor litter breakdown rates were correlated with ambient organic matter biomass. The similarity in litter breakdown rates appears to have been driven by a functional similarity among the cave communities. Potential leaf shredding macroinvertebrates were nearly absent in all caves and only contributed 2 to 17% of total macroinvertebrate biomass. Surface-adapted species dominated the biomass in litter bags in this study, suggesting that surface-adapted species have a greater effect on cave ecosystem processes than the cave-adapted taxa that have been the traditional focus of cave studies. The litter breakdown rates, community diversity within each cave (e.g., lack of leaf shredders and dominance of surface-adapted species), and the lack of correlation between litter breakdown rate and organic matter biomass found in this study are broadly similar to those found in previous litter breakdown studies in cave streams. These broad-scale similarities suggest that the factors that control litter breakdown and community structure within caves may thus be generally similar across geographically diverse areas. In Chapter Three, a short-term (one year) litter amendment experiment was conducted to examine the relationship between cave community structure and organic matter availability. Non-transgenic corn (Zea mays) litter was added to a 100-m reach of cave stream and the response in consumer biomass and carbon source was followed relative to that of an upstream reference reach. Following the litter amendment the biomass of surface-adapted species significantly increased, while the biomass of obligate-cave species remained unchanged. This response appears to be related to the evolutionary history of the species. The suite of 133
characteristics (e.g., higher growth rates and fecundity) that allow surface-adapted species to survive in energy-rich surface streams also likely allowed them to exploit the large quantities of additional resources present within the cave stream following the litter amendment. In contrast, obligate-cave species are adapted (e.g., reduced growth rates and fecundities) to survive in the energy-poor cave environment, which likely prevented a large biomass response to the shortterm increase of resources following the amendment. These differences in evolutionary history also likely explain the dominance of surface-adapted species in the litter breakdown experiments conducted in Chapter 2, because the litter bags utilized in the experiments were essentially small resource islands that were analogous to the manipulation reach in Chapter 3. Thus, while cave communities have the ability exploit short-term increases in energy availability, species-specific responses are dictated by their evolutionary history. A commonly cited convergent trait that many obligate cave species have evolved in the energy-limited cave environment is K-selected life history characteristics, which are characterized by longer life spans and slower growth rates. One species that has been used as a textbook example to illustrate K-selected evolution in obligate cave species is Orconectes australis, whose time to maturity and longevity were estimated at 35 and 176 years, respectively (Cooper 1975). However, uncertainties surrounded these extraordinary estimates. Chapter 4 used a 5+-year mark-recapture data set to re-examine the time-to-maturity, age-at-first-reproduction, and longevity of three populations of O. australis. The results from Chapter 4 indicate that accurate estimates of the longevity of O. australis are
Page 1 and 2:
THE INFLUENCE OF ENERGY AVAILABILIT
Page 3 and 4:
ABSTRACT Detritus from surface envi
Page 5 and 6:
LIST OF ABBREVIATIONS AND SYMBOLS m
Page 7 and 8:
NC IL ON U.K. VIAT VIE Fig. North C
Page 9 and 10:
AIC K-S Akaike information criterio
Page 11 and 12:
laboratory work and was an excellen
Page 13 and 14:
LIST OF TABLES TABLE 2.1 TABLE 2.2
Page 15 and 16:
LIST OF FIGURES FIGURE 2.1 (a) Box
Page 17 and 18:
FIGURE 4.3 Growth models for Orcone
Page 19 and 20:
chemolithoautotrophy-based systems;
Page 21 and 22:
ecology, 51, 31-53. Gibert J. & Cul
Page 23 and 24:
CHAPTER 2 EFFECTS OF ORGANIC MATTER
Page 25 and 26:
community structure in cave “pits
Page 27 and 28:
communities and how variation in co
Page 29 and 30:
the different source locations was
Page 31 and 32:
of natural-log transformed data (%
Page 33 and 34:
peak in organic matter in Big Mouth
Page 35 and 36:
Figs. 5a, b). The breakdown rate of
Page 37 and 38:
per litter bag. Similarly, Huntsman
Page 39 and 40:
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 and 92:
CHAPTER 4 REXAMINING EXTREME LONGEI
Page 93 and 94:
individuals, he predicted that it w
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
Page 143 and 144: Table 3. Continued Tanypodinae 0.03
Page 145 and 146: Table 5. Estimates of mean wood and
Page 147 and 148: Figure 1. (A) Box and whisker plot
Page 149: CHAPTER 6 OVERALL CONCLUSIONS Due t
Page 153 and 154: characteristics, highly efficient p
show all

TITLE PAGE - acumen - The University of Alabama

Create successful ePaper yourself

Delete template?

Save as template?