Urban streams globally are ch aracterised by degraded habitat conditions and low aquatic biodiver... more Urban streams globally are ch aracterised by degraded habitat conditions and low aquatic biodiversity, attributed in large part to the effects of stormwater inputs and channel modification and maintenance. Recent work in Hamilton City has highlighted the ability of some threatened fish species to survive in urban streams that retain habitat complexity in vegetated gullies, and the presence of diverse stream invertebrate communities in small streams and seepages that remain disconnected from the stormwater network. Recently completed research to assist the City's gully restoration programme has shown that it is comparatively easy to establish a low diversity indigenous forest canopy on bared sites within 20 years, and by this stage, some early maturing canopy species will be starting to regenerate. Shade and bank stability provided by restored vegetation shou ld assist in mitigating some of the effects of stormwater inputs on stream biota. Furthermore, retention of large pieces of wood in stream channels will help provide refugia for fish from stormflows, and release of juvenile galaxiid fish may provide a method of population restoration. Active introduction and stabilisation of wood may be required until restored riparian vegetation matures sufficiently to provide a long-term supply of wood.
Tree species in the Pinaceae are some of the most widely introduced non-native tree species globa... more Tree species in the Pinaceae are some of the most widely introduced non-native tree species globally, especially in the southern hemisphere. In New Zealand, plantations of radiata pine (Pinus radiata D. Don) occupy c. 1.6 million ha and form 90% of planted forests. Although radiata pine has naturalized since 1904, there is a general view in New Zealand that this species has not invaded widely. We comprehensively review where radiata pine has invaded throughout New Zealand. We used a combination of observational data and climate niche modelling to reveal that invasion has occurred nationally. Climate niche modelling demonstrates that while current occurrences are patchy, up to 76% of the land area (i.e. 211,388 km2) is climatically capable of supporting populations. Radiata pine has mainly invaded grasslands and shrublands, but also some forests. Notably, it has invaded lower-statured vegetation, including three classes of naturally uncommon ecosystems, primary successions and second...
Description de la flore et vegetation, des stades de succession et evolution dans 4 sites de Nouv... more Description de la flore et vegetation, des stades de succession et evolution dans 4 sites de Nouvelle Zelande
Pollen diagrams are presented from two mires on the flanks of the recently active andesite strato... more Pollen diagrams are presented from two mires on the flanks of the recently active andesite stratovolcano of Mt Egmont. The diagrams span the last 3500 years, and record both climatic and volcanic induced changes to the broadleaf-podocarp forests, scrub, and shrublands which clothe the slopes of Mt Egmont and the adjacent Pouakai Range to the north.Libocedrus bidwillii and Weinmannia racemosa are common trees in the upper montane forest. Both have fluctuated in abundance over the past 3500 years, with Libocedrus being most abundant between c. 3000 and 2500 years ago, and c. 1400 and 450 years ago, and Weinmannia more common in the intervening periods. Libocedrus dominance is associated with evidence for slope instability, and it is suggested that it reflects cooler, stormier conditions.There is little evidence for climatically induced vegetation change in the lower montane forests, except that Ascarina lucida became rare after c. 1400 years ago, which many also indicate cooler conditions.The last two major eruptive episodes from Mt Egmont, the first grouped into the Newall Formation (c. 1500 A.D.), and the second principally comprising the Burrell Lapilli (c. 1650 A.D.), disrupted surrounding forest. The Newall eruptions affected forests on the north-west slopes, and the Burrell Lapilli those to the east and south-east. Both events destroyed forest and disrupted canopies, thus giving rise to secondary successions which were at first dominated by Coriaria, but later by dense stands of Weinmannia. It has only been in the last 100 years that these Weinmannia stands have begun to open out and the forest to return to its pre-emption state.Anthropogenic influence is indicated by high levels of Pteridium spores after c. 1500 A.D., a consequence of Polynesian clearance of the coastal lowlands of Taranaki.
Urban streams globally are characterised by degraded habitat conditions and low aquatic biodivers... more Urban streams globally are characterised by degraded habitat conditions and low aquatic biodiversity, attributed in large part to the effects of stormwater inputs and channel modification and maintenance. Recent work in Hamilton City has highlighted the ability of some threatened fish species to survive in urban streams that retain habitat complexity in vegetated gullies, and the presence of diverse stream invertebrate communities in small streams and seepages that remain disconnected from the stormwater network. Recently completed research to assist the City’s gully restoration programme has shown that it is comparatively easy to establish a low diversity indigenous forest canopy on bared sites within 20 years, and by this stage, some early maturing canopy species will be starting to regenerate. Shade and bank stability provided by restored vegetation should assist in mitigating some of the effects of stormwater inputs on stream biota. Furthermore, retention of large pieces of wood...
A new, diploid species of Coprosma, C. pedicellata (2n = 44) is described and illustrated. It has... more A new, diploid species of Coprosma, C. pedicellata (2n = 44) is described and illustrated. It has a close morphological affinity with the northern New Zealand hexaploid species C. parviflora (2n = 132), which may be an ancient amphidiploid derivative. C. pedicellata is readily identified by its distinctive growth habit, habitat, and pendant pedicellate violet drupes. It is known from a few disjunct localities along the foothills of eastern New Zealand where it is restricted to forest or forest margins, usually on moderately fertile soils with impeded drainage, in overflow and flood channels, and alongside small streams. It shares these cool winter‐wet/warm summer‐dry habitats with a select group of woody species, including other rare small‐leaved divaricate shrubs and dwarf mistletoes. C. pedicellata is considered to be a restricted taxon in need of active conservation management over the greater part of its present natural range.
Page 1. This article was downloaded by: [66.249.67.44] On: 09 July 2011, At: 15:47 Publisher: Tay... more Page 1. This article was downloaded by: [66.249.67.44] On: 09 July 2011, At: 15:47 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK ...
Alseuosmia quercifolia A.Cunn., previously treated as a hybrid (A. ×quercifolia) or as an entity ... more Alseuosmia quercifolia A.Cunn., previously treated as a hybrid (A. ×quercifolia) or as an entity informally known as A. sp. "Hakarimata", is reinstated as a distinct species. This species occurs most commonly in lowland native forests of the Waikato region (from 38OS), but also occurs in sparse populations as far north as North Cape. Although lamina morphology is somewhat variable, A. quercifolia has a set of morphological characters unique to the species and not intermediate between formerly putative parents A. banksii and A. macrophylla. It is distinguished from A. banksii by its slightly larger flower, larger leaf, different petiole and lamina colour, distinctive pale venation of seedling leaves, and later flowering season; from A. macrophylla by its smaller flower, and by different lamina, petiole, and stem colour; and from A. pusilla and A. turneri by its different petiole and lamina colour.
Volcanic activity has damaged or destroyed at least 20,000 ha of indigenous vegetation in the Nor... more Volcanic activity has damaged or destroyed at least 20,000 ha of indigenous vegetation in the North Island in the last 450 years. The primary and secondary successions initiated are discussed and considered in relation to some recently proposed models of succession. Most of the variation relates to the scale and intensity of disturbance, and the type and heterogeneity of the substrate emplaced. Where disturbance has been extensive and severe, elements of slow 'classical' successions, from lichens and mosses to flowering plants, and facilitation by nitrogen-fixers such as Coriaria spp., are evident. In contrast, minor disturbance results in vegetative regrowth or regeneration of surviving species. Heterogeneity of substrate enables many taxonomic plant groups to establish more or less concurrently. Partial disturbance successions are not easily categorised and may contain elements of several successional models. The resource-ratio hypothesis of succession can be used to expla...
Hamilton City has less than 20 ha of high quality indigenous species dominated ecosystem and only... more Hamilton City has less than 20 ha of high quality indigenous species dominated ecosystem and only 1.6% of the original indigenous vegetation remains within the ecological district. A gradual recognition of the magnitude of landscape transformation has gathered momentum to the stage that there is now a concerted public and private effort to retrofit the City by restoring and reconstructing indigenous ecosystems. The initial focus was on rehabilitating existing key sites but has shifted to restoring parts of the distinctive gully landform that occupies some 750 ha or 8% of the City. A new initiative at Waiwhakareke (Horseshoe Lake) will involve reconstruction from scratch of a range of ecosystems characteristic of the ecological district over an area of 60 ha. This paper examines a vision for ecological restoration in Hamilton City within the context of policy, education and community dimensions that have triggered a shift from traditional parks and gardens management to ecosystem man...
Reconstruction of ecosystems is required to achieve a target of 10% indigenous cover in cities: t... more Reconstruction of ecosystems is required to achieve a target of 10% indigenous cover in cities: the addition of land to land banks for this purpose is crucial. Future planning that protects indigenous remnants within the periurban zone is critical to the survival of many species within urban areas, mitigating the homogenisation and depletion of indigenous flora and fauna typical of urbanisation. A national urban biodiversity plan would help city councils address biodiversity issues beyond a local and regional focus, while encouraging predominantly local solutions to restoration challenges, based on the highly variable land environments, ecosystems and patch connectivity present within different urban areas. cities (n=20). Data analysis uses LENZ Level IV and LCDB2. ____________ 11 Table 3. Indigenous landcover types, and water environments, represented within the urban core of the largest 20 New Zealand cities, and the current area. _______ 14
Hebe adamsii (Cheeseman) Cockayne et Allan, treated as a hybrid or as an unnamed species since 19... more Hebe adamsii (Cheeseman) Cockayne et Allan, treated as a hybrid or as an unnamed species since 1961, is reinstated as a distinct species. It is endemic to the Unuwhao massif in the far north of the North Island. It is similar to H. ligustrifolia, but has a sinus in the leaf bud and larger flowers and capsules. H. murrellii Simpson et Thomson, treated since 1961 as H. petriei var. murrellii, grows sympatrically with H. petriei var. petriei on the Takitimu Mountains, Southland, and is reinstated at species rank. H. murrellii and H. petriei axe probably closely related, but differ in their leaf bases and flowers. Descriptions of both reinstated species are provided.
Pattern and process of vegetation change (succession) were compared on two northern North Island ... more Pattern and process of vegetation change (succession) were compared on two northern North Island volcanoes: Whakaari (White Island) and Rangitoto Island where the endemic woody tree Metrosideros excelsa is the primary colonizer of raw volcanic substrates. Quantitative data from our previous publications (see References) and the references therein illustrate sequences of vegetation succession following significant volcanic eruptions. New information on Rangitoto Island M. excelsa patch dynamics and updated vascular species statistics for Whakaari have also been included. We also draw on supporting data from M. excelsa forest on the mainland and long-inactive volcanic islands in the Bay of Plenty, to provide a context for understanding the vegetation dynamics on Whakaari and Rangitoto Island. Species facilitation, light availability, humidity, substrate and disturbance history are all key determinants of vegetation succession across these volcanic landscapes.
New Zealand's formerly extensive lowland native forests have been comprehensively cleared or modi... more New Zealand's formerly extensive lowland native forests have been comprehensively cleared or modified, and large areas of secondary-growth vegetation have subsequently established. These areas are comprised of native, exotic, and mixed tree and shrub species assemblages. The mature-phase canopy and emergent tree species representative of pre-human New Zealand forests are often rare or locally extinct in these forests, indicating negative ramifications for long-term biodiversity conservation and ecosystem service provision, especially such as carbon sequestration. The successful recruitment of mature-phase canopy and emergent tree species may be prevented by biotic and abiotic filters related to dispersal (e.g. lack of seed sources or lack of dispersal agents), environmental variation (e.g. unsuitable germination microclimate or light availability), and competition (e.g. exotic weed competition). Failure of mature-phase tree species to cross through these filters may halt forest succession and cause arrested development of the ecosystem. There are also social and cultural imperatives for restoring mature-phase tree species, such as reassembling desired forest habitat and landscapes and providing lost natural heritage and cultural resources. Therefore, to restore secondary forests, depauperate remnant forests and create new forests that have complex structure, high biomass, and natural canopy tree diversity, mature-phase canopy and emergent species should be reintroduced through human interventions (i.e. enrichment planting). Experiments demonstrate that mature-phase tree species establishment can be optimised through canopy manipulation to address competition for light. Such targeted management can determine successful recruitment of mature-phase tree species, as can weed maintenance post-enrichment planting and landscape-level pest animal control. Currently political focus is emphasising planting of new early-successional native forests. However, support from scientific research and policy development is essential to actively recruit mature-phase tree species where they are now poorly represented and hence forest succession may be arrested. Afforestation and emissions trading policies need to support the reinstatement of mature-phase tree species within existing regenerating and degraded forests and newly created forests to facilitate the substantial ecological and ecosystem service benefits they provide over the long-term.
Ecological applications : a publication of the Ecological Society of America, 2017
Restoring forest structure and composition is an important component of urban land management, bu... more Restoring forest structure and composition is an important component of urban land management, but we lack clear understanding of the mechanisms driving restoration success. Here we studied two indicators of restoration success in temperate rainforests: native tree regeneration and epiphyte colonization. We hypothesized that ecosystem properties such as forest canopy openness, abundance of exotic herbaceous weeds, and the microclimate directly affect the density and diversity of native tree seedlings and epiphytes. Relationships between environmental conditions and the plant community were investigated in 27 restored urban forests spanning 3-70 years in age and in unrestored and remnant urban forests. We used structural equation modelling to determine the direct and indirect drivers of native tree regeneration and epiphyte colonization in the restored forests. Compared to remnant forest, unrestored forest had fewer native canopy tree species, significantly more light reaching the fo...
Urban streams globally are ch aracterised by degraded habitat conditions and low aquatic biodiver... more Urban streams globally are ch aracterised by degraded habitat conditions and low aquatic biodiversity, attributed in large part to the effects of stormwater inputs and channel modification and maintenance. Recent work in Hamilton City has highlighted the ability of some threatened fish species to survive in urban streams that retain habitat complexity in vegetated gullies, and the presence of diverse stream invertebrate communities in small streams and seepages that remain disconnected from the stormwater network. Recently completed research to assist the City's gully restoration programme has shown that it is comparatively easy to establish a low diversity indigenous forest canopy on bared sites within 20 years, and by this stage, some early maturing canopy species will be starting to regenerate. Shade and bank stability provided by restored vegetation shou ld assist in mitigating some of the effects of stormwater inputs on stream biota. Furthermore, retention of large pieces of wood in stream channels will help provide refugia for fish from stormflows, and release of juvenile galaxiid fish may provide a method of population restoration. Active introduction and stabilisation of wood may be required until restored riparian vegetation matures sufficiently to provide a long-term supply of wood.
Tree species in the Pinaceae are some of the most widely introduced non-native tree species globa... more Tree species in the Pinaceae are some of the most widely introduced non-native tree species globally, especially in the southern hemisphere. In New Zealand, plantations of radiata pine (Pinus radiata D. Don) occupy c. 1.6 million ha and form 90% of planted forests. Although radiata pine has naturalized since 1904, there is a general view in New Zealand that this species has not invaded widely. We comprehensively review where radiata pine has invaded throughout New Zealand. We used a combination of observational data and climate niche modelling to reveal that invasion has occurred nationally. Climate niche modelling demonstrates that while current occurrences are patchy, up to 76% of the land area (i.e. 211,388 km2) is climatically capable of supporting populations. Radiata pine has mainly invaded grasslands and shrublands, but also some forests. Notably, it has invaded lower-statured vegetation, including three classes of naturally uncommon ecosystems, primary successions and second...
Description de la flore et vegetation, des stades de succession et evolution dans 4 sites de Nouv... more Description de la flore et vegetation, des stades de succession et evolution dans 4 sites de Nouvelle Zelande
Pollen diagrams are presented from two mires on the flanks of the recently active andesite strato... more Pollen diagrams are presented from two mires on the flanks of the recently active andesite stratovolcano of Mt Egmont. The diagrams span the last 3500 years, and record both climatic and volcanic induced changes to the broadleaf-podocarp forests, scrub, and shrublands which clothe the slopes of Mt Egmont and the adjacent Pouakai Range to the north.Libocedrus bidwillii and Weinmannia racemosa are common trees in the upper montane forest. Both have fluctuated in abundance over the past 3500 years, with Libocedrus being most abundant between c. 3000 and 2500 years ago, and c. 1400 and 450 years ago, and Weinmannia more common in the intervening periods. Libocedrus dominance is associated with evidence for slope instability, and it is suggested that it reflects cooler, stormier conditions.There is little evidence for climatically induced vegetation change in the lower montane forests, except that Ascarina lucida became rare after c. 1400 years ago, which many also indicate cooler conditions.The last two major eruptive episodes from Mt Egmont, the first grouped into the Newall Formation (c. 1500 A.D.), and the second principally comprising the Burrell Lapilli (c. 1650 A.D.), disrupted surrounding forest. The Newall eruptions affected forests on the north-west slopes, and the Burrell Lapilli those to the east and south-east. Both events destroyed forest and disrupted canopies, thus giving rise to secondary successions which were at first dominated by Coriaria, but later by dense stands of Weinmannia. It has only been in the last 100 years that these Weinmannia stands have begun to open out and the forest to return to its pre-emption state.Anthropogenic influence is indicated by high levels of Pteridium spores after c. 1500 A.D., a consequence of Polynesian clearance of the coastal lowlands of Taranaki.
Urban streams globally are characterised by degraded habitat conditions and low aquatic biodivers... more Urban streams globally are characterised by degraded habitat conditions and low aquatic biodiversity, attributed in large part to the effects of stormwater inputs and channel modification and maintenance. Recent work in Hamilton City has highlighted the ability of some threatened fish species to survive in urban streams that retain habitat complexity in vegetated gullies, and the presence of diverse stream invertebrate communities in small streams and seepages that remain disconnected from the stormwater network. Recently completed research to assist the City’s gully restoration programme has shown that it is comparatively easy to establish a low diversity indigenous forest canopy on bared sites within 20 years, and by this stage, some early maturing canopy species will be starting to regenerate. Shade and bank stability provided by restored vegetation should assist in mitigating some of the effects of stormwater inputs on stream biota. Furthermore, retention of large pieces of wood...
A new, diploid species of Coprosma, C. pedicellata (2n = 44) is described and illustrated. It has... more A new, diploid species of Coprosma, C. pedicellata (2n = 44) is described and illustrated. It has a close morphological affinity with the northern New Zealand hexaploid species C. parviflora (2n = 132), which may be an ancient amphidiploid derivative. C. pedicellata is readily identified by its distinctive growth habit, habitat, and pendant pedicellate violet drupes. It is known from a few disjunct localities along the foothills of eastern New Zealand where it is restricted to forest or forest margins, usually on moderately fertile soils with impeded drainage, in overflow and flood channels, and alongside small streams. It shares these cool winter‐wet/warm summer‐dry habitats with a select group of woody species, including other rare small‐leaved divaricate shrubs and dwarf mistletoes. C. pedicellata is considered to be a restricted taxon in need of active conservation management over the greater part of its present natural range.
Page 1. This article was downloaded by: [66.249.67.44] On: 09 July 2011, At: 15:47 Publisher: Tay... more Page 1. This article was downloaded by: [66.249.67.44] On: 09 July 2011, At: 15:47 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK ...
Alseuosmia quercifolia A.Cunn., previously treated as a hybrid (A. ×quercifolia) or as an entity ... more Alseuosmia quercifolia A.Cunn., previously treated as a hybrid (A. ×quercifolia) or as an entity informally known as A. sp. "Hakarimata", is reinstated as a distinct species. This species occurs most commonly in lowland native forests of the Waikato region (from 38OS), but also occurs in sparse populations as far north as North Cape. Although lamina morphology is somewhat variable, A. quercifolia has a set of morphological characters unique to the species and not intermediate between formerly putative parents A. banksii and A. macrophylla. It is distinguished from A. banksii by its slightly larger flower, larger leaf, different petiole and lamina colour, distinctive pale venation of seedling leaves, and later flowering season; from A. macrophylla by its smaller flower, and by different lamina, petiole, and stem colour; and from A. pusilla and A. turneri by its different petiole and lamina colour.
Volcanic activity has damaged or destroyed at least 20,000 ha of indigenous vegetation in the Nor... more Volcanic activity has damaged or destroyed at least 20,000 ha of indigenous vegetation in the North Island in the last 450 years. The primary and secondary successions initiated are discussed and considered in relation to some recently proposed models of succession. Most of the variation relates to the scale and intensity of disturbance, and the type and heterogeneity of the substrate emplaced. Where disturbance has been extensive and severe, elements of slow 'classical' successions, from lichens and mosses to flowering plants, and facilitation by nitrogen-fixers such as Coriaria spp., are evident. In contrast, minor disturbance results in vegetative regrowth or regeneration of surviving species. Heterogeneity of substrate enables many taxonomic plant groups to establish more or less concurrently. Partial disturbance successions are not easily categorised and may contain elements of several successional models. The resource-ratio hypothesis of succession can be used to expla...
Hamilton City has less than 20 ha of high quality indigenous species dominated ecosystem and only... more Hamilton City has less than 20 ha of high quality indigenous species dominated ecosystem and only 1.6% of the original indigenous vegetation remains within the ecological district. A gradual recognition of the magnitude of landscape transformation has gathered momentum to the stage that there is now a concerted public and private effort to retrofit the City by restoring and reconstructing indigenous ecosystems. The initial focus was on rehabilitating existing key sites but has shifted to restoring parts of the distinctive gully landform that occupies some 750 ha or 8% of the City. A new initiative at Waiwhakareke (Horseshoe Lake) will involve reconstruction from scratch of a range of ecosystems characteristic of the ecological district over an area of 60 ha. This paper examines a vision for ecological restoration in Hamilton City within the context of policy, education and community dimensions that have triggered a shift from traditional parks and gardens management to ecosystem man...
Reconstruction of ecosystems is required to achieve a target of 10% indigenous cover in cities: t... more Reconstruction of ecosystems is required to achieve a target of 10% indigenous cover in cities: the addition of land to land banks for this purpose is crucial. Future planning that protects indigenous remnants within the periurban zone is critical to the survival of many species within urban areas, mitigating the homogenisation and depletion of indigenous flora and fauna typical of urbanisation. A national urban biodiversity plan would help city councils address biodiversity issues beyond a local and regional focus, while encouraging predominantly local solutions to restoration challenges, based on the highly variable land environments, ecosystems and patch connectivity present within different urban areas. cities (n=20). Data analysis uses LENZ Level IV and LCDB2. ____________ 11 Table 3. Indigenous landcover types, and water environments, represented within the urban core of the largest 20 New Zealand cities, and the current area. _______ 14
Hebe adamsii (Cheeseman) Cockayne et Allan, treated as a hybrid or as an unnamed species since 19... more Hebe adamsii (Cheeseman) Cockayne et Allan, treated as a hybrid or as an unnamed species since 1961, is reinstated as a distinct species. It is endemic to the Unuwhao massif in the far north of the North Island. It is similar to H. ligustrifolia, but has a sinus in the leaf bud and larger flowers and capsules. H. murrellii Simpson et Thomson, treated since 1961 as H. petriei var. murrellii, grows sympatrically with H. petriei var. petriei on the Takitimu Mountains, Southland, and is reinstated at species rank. H. murrellii and H. petriei axe probably closely related, but differ in their leaf bases and flowers. Descriptions of both reinstated species are provided.
Pattern and process of vegetation change (succession) were compared on two northern North Island ... more Pattern and process of vegetation change (succession) were compared on two northern North Island volcanoes: Whakaari (White Island) and Rangitoto Island where the endemic woody tree Metrosideros excelsa is the primary colonizer of raw volcanic substrates. Quantitative data from our previous publications (see References) and the references therein illustrate sequences of vegetation succession following significant volcanic eruptions. New information on Rangitoto Island M. excelsa patch dynamics and updated vascular species statistics for Whakaari have also been included. We also draw on supporting data from M. excelsa forest on the mainland and long-inactive volcanic islands in the Bay of Plenty, to provide a context for understanding the vegetation dynamics on Whakaari and Rangitoto Island. Species facilitation, light availability, humidity, substrate and disturbance history are all key determinants of vegetation succession across these volcanic landscapes.
New Zealand's formerly extensive lowland native forests have been comprehensively cleared or modi... more New Zealand's formerly extensive lowland native forests have been comprehensively cleared or modified, and large areas of secondary-growth vegetation have subsequently established. These areas are comprised of native, exotic, and mixed tree and shrub species assemblages. The mature-phase canopy and emergent tree species representative of pre-human New Zealand forests are often rare or locally extinct in these forests, indicating negative ramifications for long-term biodiversity conservation and ecosystem service provision, especially such as carbon sequestration. The successful recruitment of mature-phase canopy and emergent tree species may be prevented by biotic and abiotic filters related to dispersal (e.g. lack of seed sources or lack of dispersal agents), environmental variation (e.g. unsuitable germination microclimate or light availability), and competition (e.g. exotic weed competition). Failure of mature-phase tree species to cross through these filters may halt forest succession and cause arrested development of the ecosystem. There are also social and cultural imperatives for restoring mature-phase tree species, such as reassembling desired forest habitat and landscapes and providing lost natural heritage and cultural resources. Therefore, to restore secondary forests, depauperate remnant forests and create new forests that have complex structure, high biomass, and natural canopy tree diversity, mature-phase canopy and emergent species should be reintroduced through human interventions (i.e. enrichment planting). Experiments demonstrate that mature-phase tree species establishment can be optimised through canopy manipulation to address competition for light. Such targeted management can determine successful recruitment of mature-phase tree species, as can weed maintenance post-enrichment planting and landscape-level pest animal control. Currently political focus is emphasising planting of new early-successional native forests. However, support from scientific research and policy development is essential to actively recruit mature-phase tree species where they are now poorly represented and hence forest succession may be arrested. Afforestation and emissions trading policies need to support the reinstatement of mature-phase tree species within existing regenerating and degraded forests and newly created forests to facilitate the substantial ecological and ecosystem service benefits they provide over the long-term.
Ecological applications : a publication of the Ecological Society of America, 2017
Restoring forest structure and composition is an important component of urban land management, bu... more Restoring forest structure and composition is an important component of urban land management, but we lack clear understanding of the mechanisms driving restoration success. Here we studied two indicators of restoration success in temperate rainforests: native tree regeneration and epiphyte colonization. We hypothesized that ecosystem properties such as forest canopy openness, abundance of exotic herbaceous weeds, and the microclimate directly affect the density and diversity of native tree seedlings and epiphytes. Relationships between environmental conditions and the plant community were investigated in 27 restored urban forests spanning 3-70 years in age and in unrestored and remnant urban forests. We used structural equation modelling to determine the direct and indirect drivers of native tree regeneration and epiphyte colonization in the restored forests. Compared to remnant forest, unrestored forest had fewer native canopy tree species, significantly more light reaching the fo...
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