title: Restiad bog development and nutrient dynamics of the dominant species

authors: Clarkson, Beverley R.

subjects: bog succession

abstract: Vegetation and peat in lowland restiad (dominated by Restionaceae) raised bogs on North Island (Waikato region) and Chatham Island, New Zealand, were sampled to investigate the main environmental controls of pattern and change. Vegetation classification based on a chronosequence of Waikato restiad bogs revealed a sequence from sedges, through Empodisma minus, the main peatforming restiad, to phases dominated by a second restiad, Sporadanthus ferrugineus. The sequence paralleled temporal successional patterns and was used for interpreting plant-nutrient dynamics along a successional gradient. As succession proceeds, von Post (an index of peat decomposition), total P, total N and % ash in peat decrease. Empodisma was considered to be the key species in restiad bog development. It is tolerant of a wide environmental range, establishing early in minerotrophic wetlands to initiate restiad bog development, and persisting through to late ombrotrophic phases. On Chatham Island, the ecological role of Sporadanthus traversii in restiad bog development is similar to Empodisma in Waikato, being the main peat former and occupying a wide environmental range. Peat under S. traversii had significantly higher total N, total K, available P, bulk density and von Post, and lower pH than Waikato peats under S. ferrugineus or Empodisma. This was attributed to a strong oceanic influence and long history of sea-bird nutrient inputs. 
Nutrient responses in the heath and restiad components of the bog were compared by measuring plant ¹⁵N natural abundance across N and P gradients. Heath shrubs revealed considerable isotopic variation (-2.03 to - 15.55 for Leptospermum scoparium), with foliar δ¹⁵N strongly positively correlated with P concentrations in foliage and peat. In contrast, restiad species revealed little isotopic variation, with Empodisma and S. traversii having δ¹⁵N levels around 0‰, and S. ferrugineus being significantly more depleted (mean -4.97‰). The differences in ii isotopic signatures between heath shrubs and restiads were linked to contrasting nutrient demands, acquisition mechanisms, and root morphology. Leptospermum shrubs on low nutrient peats were stunted, with low foliar %P and high N:P ratios, suggesting they were P-limited. The concurrence of δ¹⁵N depletion and %P in plant tissues suggests N fractionation is promoted by P limitation. In contrast, the constancy in δ¹⁵N of the restiad species through the nutrient gradients indicates these may not be P-limited. 
The contrasting δ¹⁵N signatures of co-habiting Empodisma and S. ferrugineus in late successional bogs suggest the species are accessing different sources of N. Empodisma has a thick layer of cluster roots overlying the deeper S. ferrugineus roots, and would be better positioned to intercept aerially derived N. The hypothesis that this root disposition allows Empodisma to preferentially access the primary N input from rainfall was tested using a ¹⁵N-enriched tracer. At plots codominated by Empodisma and S.ferrugineus, 1.6 mmoles m-2 of 99 atom% excess ¹⁵N as (NH4)2S04 was applied to the peat surface, followed by deionised water, simulating a rainfall event of 34 mm. After 5 hours, cores were harvested and analysed for ¹⁵N. Approximately 90% of the recovered isotope was in the upper Empodisma root layer. Seven weeks after tracer application, young shoots of Empodisma were significantly enriched whereas adjacent Sporadanthus shoots were not. The results confirm that species acquire nutrients from different rooting zones, with Empodisma accessing nutrients at the surface from rainfall and S. ferrugineus acquiring nutrients from deeper peat layers. Niche differentiation facilitates species co-existence, which, on a successional time scale, may be a mechanism for slowing the rate of competitive displacement.

text: Restiad bog development and nutrient dynamics of the dominant species Vegetation and peat in lowland restiad (dominated by Restionaceae) raised bogs on North Island (Waikato region) and Chatham Island, New Zealand, were sampled to investigate the main environmental controls of pattern and change. Vegetation classification based on a chronosequence of Waikato restiad bogs revealed a sequence from sedges, through Empodisma minus, the main peatforming restiad, to phases dominated by a second restiad, Sporadanthus ferrugineus. The sequence paralleled temporal successional patterns and was used for interpreting plant-nutrient dynamics along a successional gradient. As succession proceeds, von Post (an index of peat decomposition), total P, total N and % ash in peat decrease. Empodisma was considered to be the key species in restiad bog development. It is tolerant of a wide environmental range, establishing early in minerotrophic wetlands to initiate restiad bog development, and persisting through to late ombrotrophic phases. On Chatham Island, the ecological role of Sporadanthus traversii in restiad bog development is similar to Empodisma in Waikato, being the main peat former and occupying a wide environmental range. Peat under S. traversii had significantly higher total N, total K, available P, bulk density and von Post, and lower pH than Waikato peats under S. ferrugineus or Empodisma. This was attributed to a strong oceanic influence and long history of sea-bird nutrient inputs. 
Nutrient responses in the heath and restiad components of the bog were compared by measuring plant ¹⁵N natural abundance across N and P gradients. Heath shrubs revealed considerable isotopic variation (-2.03 to - 15.55 for Leptospermum scoparium), with foliar δ¹⁵N strongly positively correlated with P concentrations in foliage and peat. In contrast, restiad species revealed little isotopic variation, with Empodisma and S. traversii having δ¹⁵N levels around 0‰, and S. ferrugineus being significantly more depleted (mean -4.97‰). The differences in ii isotopic signatures between heath shrubs and restiads were linked to contrasting nutrient demands, acquisition mechanisms, and root morphology. Leptospermum shrubs on low nutrient peats were stunted, with low foliar %P and high N:P ratios, suggesting they were P-limited. The concurrence of δ¹⁵N depletion and %P in plant tissues suggests N fractionation is promoted by P limitation. In contrast, the constancy in δ¹⁵N of the restiad species through the nutrient gradients indicates these may not be P-limited. 
The contrasting δ¹⁵N signatures of co-habiting Empodisma and S. ferrugineus in late successional bogs suggest the species are accessing different sources of N. Empodisma has a thick layer of cluster roots overlying the deeper S. ferrugineus roots, and would be better positioned to intercept aerially derived N. The hypothesis that this root disposition allows Empodisma to preferentially access the primary N input from rainfall was tested using a ¹⁵N-enriched tracer. At plots codominated by Empodisma and S.ferrugineus, 1.6 mmoles m-2 of 99 atom% excess ¹⁵N as (NH4)2S04 was applied to the peat surface, followed by deionised water, simulating a rainfall event of 34 mm. After 5 hours, cores were harvested and analysed for ¹⁵N. Approximately 90% of the recovered isotope was in the upper Empodisma root layer. Seven weeks after tracer application, young shoots of Empodisma were significantly enriched whereas adjacent Sporadanthus shoots were not. The results confirm that species acquire nutrients from different rooting zones, with Empodisma accessing nutrients at the surface from rainfall and S. ferrugineus acquiring nutrients from deeper peat layers. Niche differentiation facilitates species co-existence, which, on a successional time scale, may be a mechanism for slowing the rate of competitive displacement.

year: 2005

title: Regioisomeric preferences in the orthomanganation of meta-substituted acetophenones and isopropyl benzoates, and application of iodo-demanganation with iodine chloride to the synthesis of 2-iodo-3-O-substituted and other ortho-iodo arylcarbonyl compounds

authors: Cooney, Janine M.

subjects: Manganese

abstract: Synthesis is reported of regioisomeric ortho-[Mn(CO)4] derivatives of aryl ketones (2-chlorothioxanthen-9-one and 3′,4′-methylenedioxyacetophenone) and esters (isopropyl 3-methoxy- and 3-acetoxy-benzoate), as well as of the single ortho-[Mn(CO)4] products from methyl 4-methoxy- and 3,5-dimethoxy-benzoate. Factors influencing the preference for manganation at the crowded positions ortho to the C=O in meta-substituted aryl ketones and esters are considered. The frequency of the lowest energy metal carbonyl stretching mode is useful in the structural assignment of the regioisomers. Isopropyl 2-iodo-3-methoxy- and 2-iodo-3-acetoxy-benzoates are obtained by reaction of iodine chloride to replace the Mn(CO)4 group at the crowded 2-position of the corresponding orthomanganated 3-O-substituted benzoate esters. ortho-Iodoacetophenones were prepared likewise, without α-iodination, some with iodine in crowded positions (2′-iodo-3′-methoxy-, -3′,4′-methylenedioxy- and -3′,4′,5′-trimethoxy-acetophenone), others with O-protected 2′-hydroxy groups (2′-benzyloxy- and 2′-t-butyldimethylsilyloxy-3′,4′-dimethoxy-6′-iodobenzene and 2′-t-butyldimethylsiloxy-6′-iodobenzene). Potential general synthetic routes to derivatives of 2-iodo-3-hydroxy-, 2-iodo-3,4-dihydroxy-, and 2-iodo-6-hydroxy-aryl carbonyl compounds are indicated. The corresponding routes to 3-iodo-4-acetyl-2,5-dimethylthiophene and 3-iodo-2-acetylthiophene are also reported.

text: Regioisomeric preferences in the orthomanganation of meta-substituted acetophenones and isopropyl benzoates, and application of iodo-demanganation with iodine chloride to the synthesis of 2-iodo-3-O-substituted and other ortho-iodo arylcarbonyl compounds Synthesis is reported of regioisomeric ortho-[Mn(CO)4] derivatives of aryl ketones (2-chlorothioxanthen-9-one and 3′,4′-methylenedioxyacetophenone) and esters (isopropyl 3-methoxy- and 3-acetoxy-benzoate), as well as of the single ortho-[Mn(CO)4] products from methyl 4-methoxy- and 3,5-dimethoxy-benzoate. Factors influencing the preference for manganation at the crowded positions ortho to the C=O in meta-substituted aryl ketones and esters are considered. The frequency of the lowest energy metal carbonyl stretching mode is useful in the structural assignment of the regioisomers. Isopropyl 2-iodo-3-methoxy- and 2-iodo-3-acetoxy-benzoates are obtained by reaction of iodine chloride to replace the Mn(CO)4 group at the crowded 2-position of the corresponding orthomanganated 3-O-substituted benzoate esters. ortho-Iodoacetophenones were prepared likewise, without α-iodination, some with iodine in crowded positions (2′-iodo-3′-methoxy-, -3′,4′-methylenedioxy- and -3′,4′,5′-trimethoxy-acetophenone), others with O-protected 2′-hydroxy groups (2′-benzyloxy- and 2′-t-butyldimethylsilyloxy-3′,4′-dimethoxy-6′-iodobenzene and 2′-t-butyldimethylsiloxy-6′-iodobenzene). Potential general synthetic routes to derivatives of 2-iodo-3-hydroxy-, 2-iodo-3,4-dihydroxy-, and 2-iodo-6-hydroxy-aryl carbonyl compounds are indicated. The corresponding routes to 3-iodo-4-acetyl-2,5-dimethylthiophene and 3-iodo-2-acetylthiophene are also reported.

year: 2001-09-01

title: Contextualising social enterprise in New Zealand

authors: Grant, Suzanne Lisa Parker

subjects: business enterprise

abstract: Purpose – Social enterprise in New Zealand is still in its infancy, with no recognised framework to inform knowledge of current or future developments. In this exploratory paper, the aim is to consider four influences which are shaping the development of social enterprise in New Zealand.

Design/methodology/approach – A critical-appreciative lens utilising Habermas' concepts of the lifeworld and system informs the consideration of these influences.

Findings – Four distinct cultural and historical influences are proposed as contributing to the scope and “flavour” of social enterprise developing in New Zealand: socio-cultural norms, e.g. “Kiwi ingenuity”; the neoliberal reforms initiated by successive governments during the 1980s; Crown settlements in relation to breaches of the principles of 1840 Treaty of Waitangi; New Zealanders' as international citizens.

Originality/value – The paper shows how feedback and dialogue across the sectors, at local, national and international levels, is now required to determine how other scholars, practitioners and policy makers perceive this proposed initial framework.

text: Contextualising social enterprise in New Zealand Purpose – Social enterprise in New Zealand is still in its infancy, with no recognised framework to inform knowledge of current or future developments. In this exploratory paper, the aim is to consider four influences which are shaping the development of social enterprise in New Zealand.

Design/methodology/approach – A critical-appreciative lens utilising Habermas' concepts of the lifeworld and system informs the consideration of these influences.

Findings – Four distinct cultural and historical influences are proposed as contributing to the scope and “flavour” of social enterprise developing in New Zealand: socio-cultural norms, e.g. “Kiwi ingenuity”; the neoliberal reforms initiated by successive governments during the 1980s; Crown settlements in relation to breaches of the principles of 1840 Treaty of Waitangi; New Zealanders' as international citizens.

Originality/value – The paper shows how feedback and dialogue across the sectors, at local, national and international levels, is now required to determine how other scholars, practitioners and policy makers perceive this proposed initial framework.

year: 2008