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• 1. [Article] Accelerated Erosion of Saltmarshes Infested by the Non-Native Burrowing Crustacean Sphaeroma Quoianum

  Lateral erosion of saltmarshes is affected by many abiotic and biotic factors. While abiotic factors are typically regarded as primary drivers of erosion, biotic influences such as burrowing or bioturbating ...

  Citation × Citation Citation Abstract Copy Title: Accelerated Erosion of Saltmarshes Infested by the Non-Native Burrowing Crustacean Sphaeroma Quoianum Author: Davidson, Timothy Mathias, de Rivera, Catherine E. Year: 2010 Lateral erosion of saltmarshes is affected by many abiotic and biotic factors. While abiotic factors are typically regarded as primary drivers of erosion, biotic influences such as burrowing or bioturbating taxa can also extensively modify the physical structure of this marine habitat. Many estuaries on the Pacific coast of North America have been invaded by populations of the burrowing non-native isopod Sphaeroma quoianum, which are thought to exacerbate the erosion of saltmarshes. We conducted a mensurative experiment to examine the relationship between populations of S. quoianum and lateral erosion rate of saltmarshes in Coos Bay, Oregon, USA. After 1 yr, we measured higher lateral erosion rates, more undercutting, and higher numbers of calved and slumped marsh sections in marsh sites infested by S. quoianum than in uninfested sites. This effect was also consistent at smaller spatial scales: we found lateral erosion was 300% higher in burrowed areas than in adjacent (within approx. 1 m) unburrowed areas within infested sites. Our results suggest that the prodigious burrowing by dense populations of S. quoianum can accelerate erosion rates in saltmarshes and are substantial geomorphic agents of change in estuaries on the Pacific coast of North America. Title: Accelerated Erosion of Saltmarshes Infested by the Non-Native Burrowing Crustacean Sphaeroma Quoianum Author: Davidson, Timothy Mathias, de Rivera, Catherine E. Year: 2010 Lateral erosion of saltmarshes is affected by many abiotic and biotic factors. While abiotic factors are typically regarded as primary drivers of erosion, biotic influences such as burrowing or bioturbating taxa can also extensively modify the physical structure of this marine habitat. Many estuaries on the Pacific coast of North America have been invaded by populations of the burrowing non-native isopod Sphaeroma quoianum, which are thought to exacerbate the erosion of saltmarshes. We conducted a mensurative experiment to examine the relationship between populations of S. quoianum and lateral erosion rate of saltmarshes in Coos Bay, Oregon, USA. After 1 yr, we measured higher lateral erosion rates, more undercutting, and higher numbers of calved and slumped marsh sections in marsh sites infested by S. quoianum than in uninfested sites. This effect was also consistent at smaller spatial scales: we found lateral erosion was 300% higher in burrowed areas than in adjacent (within approx. 1 m) unburrowed areas within infested sites. Our results suggest that the prodigious burrowing by dense populations of S. quoianum can accelerate erosion rates in saltmarshes and are substantial geomorphic agents of change in estuaries on the Pacific coast of North America. Close

• 2. [Article] Northern Range Expansion and Coastal Occurrences of the New Zealand Mud Snail Potamopyrgus Antipodarum (Gray, 1843) in the Northeast Pacific

  The New Zealand mud snail Potamopyrgus antipodarum (Gray, 1843) is a common invasive species in fresh and brackish water ecosystems in Europe, Australia, Japan, and North America. In some invaded habitats, ...

  Citation × Citation Citation Abstract Copy Title: Northern Range Expansion and Coastal Occurrences of the New Zealand Mud Snail Potamopyrgus Antipodarum (Gray, 1843) in the Northeast Pacific Author: Davidson, Timothy Mathias, Brenneis, Valance E. F., de Rivera, Catherine E., Draheim, Robyn, Gillespie, Graham E. Year: 2008 The New Zealand mud snail Potamopyrgus antipodarum (Gray, 1843) is a common invasive species in fresh and brackish water ecosystems in Europe, Australia, Japan, and North America. In some invaded habitats, P. antipodarum can reach high densities (over 500,000 snails m-2) and dominate the biomass of the benthos, leading to detrimental impacts to native biota and changes in ecosystem dynamics. We report the previously unpublished occurrence of P. antipodarum in thirteen fresh and brackish water systems adjacent to the Pacific coast of North America including a new northern range for P. antipodarum: Port Alberni, Vancouver Island, British Columbia, Canada (49.2479º, -124.8395º). We hypothesize the snail was spread from the Columbia River Estuary to Port Alberni via recreational watercraft or infected fishing equipment. Its discovery in Port Alberni reveals the potential for other aquatic nuisance species in the lower Columbia River to spread to British Columbia. Resource managers on the Pacific coast should remain vigilant and educate the public to prevent the further spread of the P. antipodarum as well as other aquatic invaders. Title: Northern Range Expansion and Coastal Occurrences of the New Zealand Mud Snail Potamopyrgus Antipodarum (Gray, 1843) in the Northeast Pacific Author: Davidson, Timothy Mathias, Brenneis, Valance E. F., de Rivera, Catherine E., Draheim, Robyn, Gillespie, Graham E. Year: 2008 The New Zealand mud snail Potamopyrgus antipodarum (Gray, 1843) is a common invasive species in fresh and brackish water ecosystems in Europe, Australia, Japan, and North America. In some invaded habitats, P. antipodarum can reach high densities (over 500,000 snails m-2) and dominate the biomass of the benthos, leading to detrimental impacts to native biota and changes in ecosystem dynamics. We report the previously unpublished occurrence of P. antipodarum in thirteen fresh and brackish water systems adjacent to the Pacific coast of North America including a new northern range for P. antipodarum: Port Alberni, Vancouver Island, British Columbia, Canada (49.2479º, -124.8395º). We hypothesize the snail was spread from the Columbia River Estuary to Port Alberni via recreational watercraft or infected fishing equipment. Its discovery in Port Alberni reveals the potential for other aquatic nuisance species in the lower Columbia River to spread to British Columbia. Resource managers on the Pacific coast should remain vigilant and educate the public to prevent the further spread of the P. antipodarum as well as other aquatic invaders. Close

• 3. [Article] Damage and Alteration of Mangroves Inhabited by a Marine Wood-Borer

  Animals can exert a strong influence on the structure and function of foundation species such as mangroves. Because mangroves live at the interface of land and sea, both terrestrial and marine species ...

  Citation × Citation Citation Abstract Copy Title: Damage and Alteration of Mangroves Inhabited by a Marine Wood-Borer Author: Davidson, Timothy Mathias, de Rivera, Catherine E., Hsieh, Hwey-Lian Year: 2014 Animals can exert a strong influence on the structure and function of foundation species such as mangroves. Because mangroves live at the interface of land and sea, both terrestrial and marine species affect them, including numerous herbivores and boring species. These organisms can affect the fecundity, performance, and morphology of mangroves. In a mangrove stand in southwestern Taiwan, we discovered that mangroves were extensively damaged by woodboring isopods Sphaeroma terebrans. We examined the relationships between burrowing damage from S. terebrans and metrics of mangrove fecundity, performance, and morphology. Individuals of Rhizophora stylosa that were more burrowed by isopods had significantly fewer propagules, fewer ground roots stabilizing the tree, smaller leaves, and more non-foliated twigs. Similarly, Avicennia marina with more burrows had fewer pneumatophores and lenticels (used for gaseous exchange), and pneumatophores with more necrotic tissue. The most heavily damaged trees were hollowed-out with burrows (A. marina) or fell over when their supportive root system failed (R. stylosa). These correlations suggest that marine wood-borers can negatively influence mangroves and alter tree morphology, although other stressors may also be involved. While studies have examined the effects of isopods on root-level production, we provide the first quantitative evidence that localized burrowing damage is correlated with tree-level effects. These results are consistent with other literature demonstrating the importance of sub-lethal damage by borers in shaping foundation species. Such damage may have cascading effects on the diverse assemblages of marine and terrestrial biota that use mangroves as habitat. Title: Damage and Alteration of Mangroves Inhabited by a Marine Wood-Borer Author: Davidson, Timothy Mathias, de Rivera, Catherine E., Hsieh, Hwey-Lian Year: 2014 Animals can exert a strong influence on the structure and function of foundation species such as mangroves. Because mangroves live at the interface of land and sea, both terrestrial and marine species affect them, including numerous herbivores and boring species. These organisms can affect the fecundity, performance, and morphology of mangroves. In a mangrove stand in southwestern Taiwan, we discovered that mangroves were extensively damaged by woodboring isopods Sphaeroma terebrans. We examined the relationships between burrowing damage from S. terebrans and metrics of mangrove fecundity, performance, and morphology. Individuals of Rhizophora stylosa that were more burrowed by isopods had significantly fewer propagules, fewer ground roots stabilizing the tree, smaller leaves, and more non-foliated twigs. Similarly, Avicennia marina with more burrows had fewer pneumatophores and lenticels (used for gaseous exchange), and pneumatophores with more necrotic tissue. The most heavily damaged trees were hollowed-out with burrows (A. marina) or fell over when their supportive root system failed (R. stylosa). These correlations suggest that marine wood-borers can negatively influence mangroves and alter tree morphology, although other stressors may also be involved. While studies have examined the effects of isopods on root-level production, we provide the first quantitative evidence that localized burrowing damage is correlated with tree-level effects. These results are consistent with other literature demonstrating the importance of sub-lethal damage by borers in shaping foundation species. Such damage may have cascading effects on the diverse assemblages of marine and terrestrial biota that use mangroves as habitat. Close