TY - JOUR
T1 - Hypolith Distribution Within a Dewy Drainage Basin
T2 - Possible Link to Dew or Rather to Rain?
AU - Kidron, Giora J
AU - Kronenfeld, Rafael
AU - Starinsky, Abraham
AU - McKay, Christopher
N1 - Publisher Copyright:
© 2024 The Author(s). Ecohydrology published by John Wiley & Sons Ltd.
PY - 2024
Y1 - 2024
N2 - The water source of hypoliths is a matter of controversy, with some scholars advocating the role of nonrainfall water (NRW), principally dew or fog as the main water sources, while others maintain that it is rain. In the Negev Highlands, where lichens cover > 90% of the upper surfaces of cobblestones, hypoliths may also reside on the undersides of these cobblestones. In an attempt to evaluate the possible role of rain, dew and fog, the abundance, cover and chlorophyll content of the hypoliths on 10–20 cm × 5–10 cm cobblestones was measured at five slope locations at the hilltop (HT) and the upper parts of the north-facing (NF), south-facing (SF), east-facing (EF) and west-facing (WF) slopes, which were characterised by contrasting abiotic conditions. Within each slope location, 50 and 10 cobblestones were randomly, respectively, collected to evaluate the abundance and cover and to measure their chlorophyll content. In addition, field measurements were conducted to evaluate the ability of rain, dew and fog to wet the hypoliths. Our results indicate that (a) hypoliths were confined to cobblestones lying loosely on the ground; (b) while similar chlorophyll content characterised patches with hypoliths at all slope locations, their abundance and cover were the highest at NF and WF, followed by HT, with SF and EF exhibiting the lowest values; (c) our measurements did not show direct wetting by dew, fog or rain. We therefore suggest that distillation may be the main source of water. Our suggestion implies that a reduction in rain, but even more importantly, elevated nocturnal temperatures during the rainy period, may have a great negative effect on the hypolithic population.
AB - The water source of hypoliths is a matter of controversy, with some scholars advocating the role of nonrainfall water (NRW), principally dew or fog as the main water sources, while others maintain that it is rain. In the Negev Highlands, where lichens cover > 90% of the upper surfaces of cobblestones, hypoliths may also reside on the undersides of these cobblestones. In an attempt to evaluate the possible role of rain, dew and fog, the abundance, cover and chlorophyll content of the hypoliths on 10–20 cm × 5–10 cm cobblestones was measured at five slope locations at the hilltop (HT) and the upper parts of the north-facing (NF), south-facing (SF), east-facing (EF) and west-facing (WF) slopes, which were characterised by contrasting abiotic conditions. Within each slope location, 50 and 10 cobblestones were randomly, respectively, collected to evaluate the abundance and cover and to measure their chlorophyll content. In addition, field measurements were conducted to evaluate the ability of rain, dew and fog to wet the hypoliths. Our results indicate that (a) hypoliths were confined to cobblestones lying loosely on the ground; (b) while similar chlorophyll content characterised patches with hypoliths at all slope locations, their abundance and cover were the highest at NF and WF, followed by HT, with SF and EF exhibiting the lowest values; (c) our measurements did not show direct wetting by dew, fog or rain. We therefore suggest that distillation may be the main source of water. Our suggestion implies that a reduction in rain, but even more importantly, elevated nocturnal temperatures during the rainy period, may have a great negative effect on the hypolithic population.
KW - fog
KW - lichens
KW - lithobionts
KW - Negev Desert
KW - surface wetness duration (SWD)
UR - http://www.scopus.com/inward/record.url?scp=85207941669&partnerID=8YFLogxK
U2 - 10.1002/eco.2736
DO - 10.1002/eco.2736
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:85207941669
SN - 1936-0584
JO - Ecohydrology
JF - Ecohydrology
ER -