Increase of human over natural erosion rates in tropical highlands constrained by cosmogenic nuclides

Hewawasam, Tilak; Blanckenburg, Friedhelm von; Schaller, Mirjam; Kubik, Peter W.

doi:10.1130/0091-7613(2003)031<0597:iohone>2.0.co;2

Cited by 165 publications

(131 citation statements)

References 19 publications

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“…The immediate threats of sedimentation from urban development and increasing human population growth, dredging, beach replenishment, land reclamation, and industrial and domestic discharges along shorelines can lead to increased rates of sediment loading into the intertidal region (Airoldi, 2003). For instance, Hewawasam et al (2003) reported that intense rainfall increased terrestrial runoffs and sediment deposition into intertidal zones in Sri Lanka. Heavy sedimentation can prevent trapped animals from escaping.…”

Section: Crustacean Research 46mentioning

confidence: 99%

Thermal tolerance of the hermit crab <i>Pagurus samuelis</i> subjected to shallow burial events

2017

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Abstract.Sedimentation and increasing temperature caused by human disturbances and global climate change are additive in their effects on coastal areas. To assess their influence on intertidal organisms, we studied the hermit crab, Pagurus samuelis, under acute temperature changes and shallow burial conditions. We applied three temperatures (5°C, 20°C, and 30°C) and two burial depths (3 cm and 6 cm) with a control at the surface (0 cm), and monitored survival, shell abandonment, and burial escape. Survival was primarily affected by temperature, with hermit crabs twice as likely to survive at 20°C than at 30°C, and at 5°C than at 30°C. The combined conditions of 30°C and 6 cm were the least favorable for survival. Hermit crabs which abandoned their shells were more likely to survive burial at 20°C and 30°C than those retaining their shells. Fewer hermit crabs abandoned their shells when exposed to 5°C than to 20°C and 30°C. Crabs buried at 6 cm were 85.0% less likely to abandon shells than those buried at 3 cm, and heavier shells were less readily abandoned than lighter shells. Although overall, 35% of hermit crabs escaped burial to the sediment surface, hermit crabs buried in the combined conditions of 30°C and 6 cm were significantly slower to reach the surface. Our results show that the combined stresses of temperature and burial can impact survival of hermit crabs in intertidal zones. While human activities, including dredging, industrial and domestic dumping, and coastal construction, result in relatively immediate increased inputs of sediment in coastal environments, climate change may endanger intertidal organisms, such as P. samuelis, living near their thermal tolerance over the long term, with both increasing temperature and sedimentation from more frequent storm events.

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Section: Crustacean Research 46mentioning

confidence: 99%

Thermal tolerance of the hermit crab <i>Pagurus samuelis</i> subjected to shallow burial events

2017

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“…An appropriate regulatory regime could provide opportunities for enhancing the economic potential of such lands by allowing for the extraction of non-timber forest produce and also their value in the sequestration of carbon. A programme of this kind may, in addition to conserving both terrestrial and riparian biodiversity, diverting revenue to rural land-owners and engendering novel publicprivate partnerships, also serve to reduce erosion from sloping lands (a serious problem in the Sri Lankan highlands: Hewawasam et al, 2003) and benefit aquatic biodiversity. Barlow et al (2007) showed for a wide range of taxa including plants, insects and vertebrates, that 43-95% of species present in primary forest were represented also in secondary forest established in areas clear-felled, burned and bulldozed 14-19 y previously, though community structure and composition differed markedly between the two forest types.…”

Section: Ecosystem Servicesmentioning

confidence: 99%

Biodiversity conservation in Sri Lanka's novel ecosystems

Pethiyagoda

2012

Ceylon J. Sci. (Biol. Sci.)

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With Sri Lanka's old-growth forests having been reduced to less than 20% of their pre-colonial extent, increasing areas of land, formerly heavily influenced by humans, are being allowed to return to secondary forests. These range from land recovering from swidden cultivation in the dry zone, through abandoned tea plantations in the lower-montane zone, to partly-logged forests throughout the country. Although the secondary vegetation of these ‗emerging ecosystems' is often dominated by alien plant species and includes only a depauperate native flora, many threatened animals, ranging from amphibians to elephants, are able to utilize them for part or all of their life cycles. These novel ecosystems offer valuable conservation opportunities in two ways: (1) by increasing the area of occupancy of threatened species they contribute directly to a reduction in the level of threat; and (2) they provide a filter for triage, whereby threatened species that are intolerant of modified habitats could be awarded higher priority in the design of recovery plans. Available data suggest that among the Sri Lankan terrestrial vertebrates presently assessed as Endangered or Critically Endangered in the IUCN Red List, 12 of 14 mammal species, three of four reptile species and 40 of 48 amphibian species occur also in emerging ecosystems. Despite their impoverished plant diversity, therefore, such ecosystems should be viewed as a conservation opportunity rather than a threat; they should be incorporated into the national protected areas network and their biodiversity monitored, especially in relation to threatened species.Those that establish stable populations over multiple generations could be down-listed so that greater conservation attention could be allocated to threatened species obligatorily dependent on old-growth forests.

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“…human-induced change (Brown et al, 1998;Hewawasam et al, 2003;Vanacker et al, 2007; 27! Reusser et al, 2015).…”

Section: !mentioning

confidence: 99%

Long-term background denudation rates of southern and southeastern Brazilian watersheds estimated with cosmogenic 10Be

et al. 2016

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LongNew data from 14 watersheds in the states of Santa Catarina (n = 7) and Rio de Janeiro (n = 7) show that erosion rates vary there from 13 to 90 m/My (mean = 32 m/My; median = 23 m/My) and that the difference between erosion rates of basins we sampled in the two states is not significant. Sampled basin area ranges between 3 and 14,987 km 2 , mean basin elevation between 235 and 1606 m, and mean basin slope between 11 and 29°. Basins sampled in Rio de Janeiro, including three that drain the Serra do Mar escarpment, have an average basin slope of 19°, whereas the average slope for the Santa Catarina basins is 14°. Mean basin slope (R 2 = 0.73) and annual precipitation (R 2 = 0.57) are most strongly correlated with erosion in the basins we studied. At three sites where we sampled river sand and cobbles, the 10 Be concentration in river sand was greater than in the cobbles, suggesting that these grain sizes are sourced from different parts of the landscape.Compiling all cosmogenic 10 Be-derived erosion rates previously published for southern and southeastern Brazil watersheds to date (n = 76) with our 14 sampled basins, we find that regional erosion rates (though low) are higher than those of watersheds also located on other passive margins including Namibia and the southeastern North America. Brazilian basins erode at a pace similar to escarpments in southeastern North America. Erosion rates in southern andsoutheastern Brazil are directly and positively related to mean basin slope (R 2 = 0.33) and weakly but significantly to mean annual precipitation (R 2 = 0.05). These relationships are weaker when considering all southern and southeastern Brazil samples than they are in our smaller, localized data set. We find that smaller, steeper headwater catchments (many on escarpments) erode faster than the larger, higher-order but lower slope catchments. Erosion in southern and southeastern Brazil appears to be controlled largely by mean basin slope with lesser influence by climate and lithology.

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Increase of human over natural erosion rates in tropical highlands constrained by cosmogenic nuclides

Cited by 165 publications

References 19 publications

Thermal tolerance of the hermit crab <i>Pagurus samuelis</i> subjected to shallow burial events

Thermal tolerance of the hermit crab <i>Pagurus samuelis</i> subjected to shallow burial events

Biodiversity conservation in Sri Lanka's novel ecosystems

Long-term background denudation rates of southern and southeastern Brazilian watersheds estimated with cosmogenic 10Be

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