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Crenshaw, Valett & Tank, 2002; Krauss et al., 2003). Simon & Benfield (2001) also found that fungal biomass was lower on leaves in cave streams without direct upstream surface connections. Thus, the relatively low rates of litter breakdown in fine-mesh bags in this study may have been caused by low microbial activity. Environmental variables (e.g. light and temperature) within cave ecosystems have traditionally been viewed as stable compared to surface systems (Juberthie, 2001), which should reduce seasonal patterns of ecosystem processes. In cave systems, temporal stability in the structure of macroinvertebrate communities and the ecological processes they mediate is probably affected substantially by reduced seasonality in environmental cues (e.g. light and temperature), continuous resource availability (which may be small or large) and reduced immigration of epigean taxa due to limited surface connectivity. Accordingly, organic matter abundance, macroinvertebrate community structure and litter breakdown rates did not differ between incubation periods in this study. Unlike most cave streams, many temperate surface systems receive seasonal pulses of detritus following plant senescence (e.g. forest headwater streams). Seasonal changes in temperature, light, hydrology and resource availability have been linked to temporal patterns in community structure, which have in turn been shown to affect organic matter processing in surface systems (e.g. Benstead & Huryn, 2011). The macroinvertebrate communities of cave streams, which contain few shredders (Brussock et al., 1988; Galas et al., 1996; Simon & Benfield, 2001), appear to process organic matter at a roughly constant rate year-round. To date, no other studies have been published that have examined temporal patterns in groundwater communities. Similar to this study, Farnleitner et al. (2005) showed that microbial communities in two karst springs showed little to no temporal variability in structure, suggesting that their ecological function may also have been stable through time. 23
Historically, limited resource inputs have been considered to be the primary factor influencing the ecology and evolution of hypogean communities. The results from this study offered mixed support for this hypothesis. Organic matter abundance was correlated neither with consumer biomass in litter bags nor litter breakdown rates. However, Tony Sinks Cave had the highest organic matter abundance and consumer biomass, suggesting that resource inputs can influence cave community biomass without corresponding effects on function (e.g. inclusion of shredding taxa). Organic matter abundance does not appear to be the primary factor influencing the presence or absence of taxa among caves in this study because Jess Elliot, Salt River, and Big Mouth caves all contained different communities despite marginal differences in organic matter abundance. However, the distinct community found in Tony Sinks Cave (e.g. indicated by its distinct grouping in the nMDS plots, Fig. 3) does suggest that organic matter abundance may play some role. Thus, in addition to organic matter abundance, other cave (e.g. surface connectivity, cave morphology and recharge area) and surface (e.g. topography and vegetation type) characteristics should be quantified to understand better the factors controlling cave community composition. Hypogean taxa have traditionally been the focus of cave studies. Nevertheless, this study suggests that their role in energy flow, nutrient cycling and food web dynamics might be relatively small in many cave systems. Hypogean taxa represented only a small proportion of the consumer biomass found in this studies litter bags. In another recent study, Huntsman et al. (2011b) showed that epigean prey contributed c. 50 to 100% of the production of the obligate cave salamander Gyrinophilus palleucus (McCrady) in two southeastern U.S.A. caves. Thus, the inclusion of the entire community, epigean and hypogean, in studies of cave ecosystems will be necessary to understand the ecological processes that occur within them. 24
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: ags was the greater retention of li
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 and 150:
CHAPTER 6 OVERALL CONCLUSIONS Due t
Page 151 and 152:
characteristics (e.g., higher growt
Page 153 and 154:
characteristics, highly efficient p
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