Tesi sul tema "Restoration ecology"

Thesis (PhD)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: The loss and degradation of habitat is recognised as the greatest threat to invertebrate biodiversity. Restoration practices have the potential to reduce these impacts. The Seychelles giant millipede (SGM), Sechelleptus seychellarum, is a threatened and functionally important macro-detritivore endemic to the Seychelles granitic islands. The broad objective of this dissertation was to investigate selected aspects of the restoration ecology of the SGM, with the intention of making practical restoration recommendations that can be used to assist in the conservation of this species. This study was carried out on Cousine Island, Seychelles between 1998 and 2009, in the context of the large-scale plant community restoration that has taken place on the island. Large fluctuations in millipede population densities were found between 1998 and 2009. In 2002, 2003, 2005 and 2007 millipede densities were low, while densities were high in 1998 and 2009. Although the SGM is active all year round, its surface activity was positively correlated with rainfall, with density high during the high rainfall period (i.e. October – April) and low during the low rainfall period (i.e. May – September). Female:male:juvenile ratios were ~ 3:1:1. The implications are that translocations should preferably be done in years of high millipede densities and during the wet season. Alien coconut trees did not affect SGM density, but negatively affected its foraging behaviour, whereas bamboo stands negatively affected both its density and foraging behaviour. The SGM showed feeding preferences for Pisonia grandis and Ficus sp. leaf litter types. Alien bamboo and coconut pose a varied threat to the SGM, and their removal and replacement by indigenous forest species (e.g. P. grandis and Ficus sp.) should form part of an island’s restoration programme. SGM density was an order of magnitude lower in the restored area compared to the natural forest. In contrast, SGM physical condition improved significantly in the restored area, as vegetation structure increased. Furthermore, SGM behaviour in the restored area switched from a predominantly walking to a predominantly feeding behaviour over the study period, resulting in the forest restoration programme on Cousine increasing the foraging area of the SGM by 43%. SGM spatial density did not significantly correlate with edaphic and litter properties, but did positively correlate with the toposcape (i.e. elevation and granitic rock cover). Granite rock crevices in forest covered areas were important diurnal refuges for the SGM, as microclimate conditions in non-forest covered rock refuges were unsuitable. SGM physical condition was significantly lower in non-shaded crevices compared to those shaded by forest. Low granite rock cover in the restored forest limited the SGM colonisation of this area in large numbers, despite canopy cover in the restored forest being comparable with that in the reference natural forest. As most restoration practices are primarily vegetation-based, this study demonstrates that such an approach can be inadequate for restoring habitat for target invertebrates, as many species’ habitat requirements extend beyond that of vegetation. For the SGM, selecting restoration sites that already have abundant rock cover would be the most practical way to increase SGM habitat through forest restoration practices. Taking into consideration the habitat requirements of target invertebrates can help in setting or redirecting restoration goals and thus enhance the conservation value of such practices.
AFRIKAANSE OPSOMMING: Die verlies en agteruitgang van habitat word alom beskou as die grootste bedreiging var die biodiversiteit van ongewerweldes. Herstellingspraktyke kan hierdie agteruitgang verminder of stop. Die Seychelle Reuse Duisendpoot (SGM), Sechelleptus seychellarum, is 'n bedreigde en funksioneel belangrike makro-detritusvoeder wat endemies is aan die Seychelle graniet-eilande. Die breë doelstelling van hierdie verhandeling is die doen van navorsing om praktiese aanbevelings te kan maak om die habitat van die SGM tot so ‘n mate te herstel dat die spesie kan bly voortbestaan. Hierdie studie is tussen 1998 en 2009 uitgevoer op Cousine Island, Seychelles, nadat ‘n grootskaalse herstellingsfase van die plantgemeenskap plaasgevind het. Groot skommelings in duisendpootgetalle is waargeneem tussen 1998 en 2009, viz. duisendpootgetalle was laag in 2002, 2003, 2005 en 2007, terwyl dit hoog was in 1998 en 2009. Alhoewel die SGM gedurende die hele jaar aktief is, is hulle tog in groter getalle aanwesig in die tydperke met hoë reënval (Oktober-April) en laag in die droë tydperk (Mei-September). Die verhouding van wyfies, mannetjies en onvolwassenes was deurgaans ~ 3:1:1. Dit bring mee dat hervestiging van SGM verkieslik gedoen moet word wanneer hul populasies hoog is en dan ook in die nat seisoen. Uitheemse klapperbome het geen invloed op SGM getalle gehad nie, alhoewel hul voedingsgedrag negatief beïnvloed is deur dié bome. Bamboesbosse darenteen, beïnvloed beide populasiedigtheid en voedingsgedrag van SGM negatief. Verder is daar gevind dat Pisonia grandis en Ficus sp. blaardetritus voorkeurvoedsel vir SGM is. Die verwydering van die uitheemse bamboes en klapperbome en vervanging daarvan met inheemse woudspesies (P. grandis en Ficus sp.) moet dus deel vorm van die eiland se herstelprogram om sodoende die SGM te bevoordeel. Die SGM-bevolkingsdigtheid was 'n grootte-orde laer in die herstelde gebied in vergelyking met die natuurlike bos, maar hul fisiese toestand het aansienlik verbeter in die herstelde gebied, waarskynlik omdat die plantegroei as geheel verbeter het. Verder het die SGM se gedrag gedurende die studietydperk in die herstelde area oorgegaan vanaf ‘n oorwegend loopgedrag om na kos te soek, na ‘n oorwegend voedende gedrag. Die vervanging van uitheemse- met inheemse boomspesies op Cousine Island het dus die voedingsarea van SGM met tot 43% verhoog. Die ruimtelike SGM populasiedigtheid is nie beduidend beïnvloed deur blaardetritus nie, maar is wel positief beïnvloed deur die topografie (hoogte en granietbedekking). Bebosde graniet rotsskeure bied belangrike toevlugsoorde vir SGM gedurende die dag, terwyl die mikroklimaat wat deur onbebosde rotsskeure veroorsaak word, totaal ongeskik is vir SGM. Die fisiese toestand van SGM was ook aansienlik swakker in die nie bebosde rotsskeure teenoor dié van die bebosde areas. In herstelde bos met min granietskuiling was die herkolonisering van SGM ook getalsgewys laer alhoewel die bosbedekking vergelykbaar was met dié van die inheemse bos. Dit bewys dus dat herstellingspraktyke wat hoofsaaklik plantegroei teiken, nie altyd die teikenspesie bevoordeel nie, maar dat ‘n meer holistiese benadering wat alle habitatvoorkeure in ag neem, toegepas moet word. Om SGM te bevoordeel moet herstel areas vir herbebossing dus gekies word waar daar reeds genoegsame granietskuiling is. Deur die habitatvereistes van ongewerwelde teikenspesies in ag te neem kan die herstellingspraktyke meer oordeelkundig ingestel word en sodoende kan die bewaringswaarde van sulke praktyke verbeter word.

The aim of this study is to investigate how human related disturbances affect mesic grasslands. I identified what was lost from the system after a disturbance and what biological constraints ecologists and managers will face when approaching their restoration. I then investigated biological limitations to grassland restoration by attempting species reintroduction into secondary grasslands and exploring the interaction between grasses and forbs.

Astragalus filipes Torrey ex. A. Gray (Fabaceae) is being studied and propagated for use in rangeland restoration projects throughout the Great Basin. Restoration forbs often require sufficient pollination services for seed production and persistence in restoration sites. Knowledge of a plant's breeding biology is important in providing pollination for maximal seed set. Reproductive output from four manual pollination treatments (autogamy, geitonogamy, xenogamy, and distant xenogamy) was examined in a common garden. Pod set, seed set, and seed germination were quantified for each of the treatments. Seed set from four wild populations was compared to that of an openly visited common garden array. A. filipes was found to be self-compatible, but to benefit greatly from outcrossing. Less seed germinated from distantly outcrossed treatments than for any other treatment, indicating possible outbreeding depression. Common garden plants set less seed per pod than any wild population, possibly due to a depauperate pollinator guild in the common garden. Bees were surveyed at wild A. filipes populations to identify common pollinators. Solitary and social bee species were observed visiting A. filipes to estimate aspects of their pollination efficacies, particularly foraging tempo and frequency of stigmatic contact. The nesting biologies of bees that visit A. filipes were considered as a component of bee manageability. Bees in the genus Osmia (Megachilidae) dominated this pollinator guild. Bombus nevadensis queens were the fastest foragers; honey bees and native solitary bees did not differ in foraging tempo. Megachilid bees consistently contacted the stigma during foraging, but honey bees exhibited sideworking behavior, contacting stigmas far less frequently than any other bee species observed. Two solitary bee species (Osmia bruneri and Hoplitis hypocrita) are recommended as prospective pollinators for management in association with Great Basin rehabilitation efforts.

Overabundance of shrubs poses a major threat to semiarid ecosystems due to degraded understory vegetation. Previous efforts suggest a need for greater understanding of which management practices work best to improve these ecosystems. I sought to develop a better understanding of how the relative performance of commonly seeded species is influenced by three sagebrush removal techniques. I calculated effect sizes for cover and frequency to estimate relative changes in abundance of 15 common plant species seeded at 63 restoration sites throughout Utah. Shrubs were reduced by fire or mechanical treatment. Effect sizes were assessed using meta-analysis techniques for two post-treatment timeframes. Introduced grasses and shrubs had greater increases in cover and frequency following treatment, respectively. The introduced shrub Bassia prostrata experienced the largest increases in abundance following treatments. Forb abundance was highest when treated with fire. Over the long term the fire treatment resulted in greater increases for four of the seven grass species. Large increases in perennial grasses over time suggest that seeding efforts contributed to enhancing understory herbaceous conditions. My results provide new insights regarding the interactive effects of species and shrub-reduction treatments. Secondly, I evaluated emergence patterns of six commonly seeded restoration species in soils collected from Wyoming big sagebrush (A. t. ssp. wyomingensis [Beetle & A. Young] S.L. Welsh) and mountain big sagebrush (A. t. ssp. vaseyana [Rydb.] Beetle) plant communities. I developed a novel experimental design that regularly wetted soils to field capacity and allowed them to naturally dry by evaporation, which resulted in distinct differences in the duration of wet-dry cycles. Results showed that inherent differences in soil texture and organic matter between vaseyana and wyomingensis soils translated into fundamental differences in soil water holding capacity. Although species collectively exhibited greater emergence in vaseyana soils than wyomingensis soil, patterns were vastly different among species and differences between soils became more pronounced under low soil water for two of the test species. I concluded that the manner in which soils and water uniquely influenced emergence patterns provide new insights in species suitability for restoration sites and how inherent soil differences may constrain seeding success.

Thesis (PhD)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: Widespread, human-induced ecosystem degradation and the associated biodiversity loss pose a direct threat to human wellbeing. While there is no substitute for healthy, self-sustaining ecosystems, ecological restoration offers an attractive, and indeed inevitable, supplement where conservation alone is not sufficient to support ecosystem integrity. Restoration is undergoing a revolution, where evidence-based (EB) practice is emerging as a new approach to increase the chances of successfully achieving restoration goals. EB practice is based on the notion that implementation decisions need to be based on the appraisal and use of evidence of effectiveness of alternative options. The point of departure of this thesis is the contention that EB practice need not be dependent only on research evidence. The work presented herein thus addresses the production and use of evidence of effectiveness in restoration practice. Using ten restoration programs in South Africa, the quality of evidence produced in practice was assessed. Three components of evidence production that were evaluated were (i) baseline condition measurement; (ii) goal setting and (iii) monitoring. Results showed poor definition of goals; a bias towards the use of socio-economic goals and indicators; more monitoring of inputs than impact; and inconsistent and short-term monitoring of biophysical indicators. Practitioners regarded the evidence base as adequate, but cited a few challenges associated with planning and resource availability as attributing factors to the gaps observed. I propose that practitioners’ perception of the current evidence base poses an additional threat to the generation of a strong evidence base. In addition to the production of evidence, access to said evidence is a vital component of EB practice. In an exploration of how evidence is made available by practitioners, it became evident in that a considerable amount of the information that was not easily accessible in documented form was known by the practitioners. This highlights the need for a shift in practice culture towards the valuing and rewarding of the dissemination of information. An assessment of EB restoration would have been incomplete without a deliberate consideration of social factors. I thus conducted a case study of an invasive alien plant clearing program, to determine what drives the use of scientific evidence in decision making. I observed that organizational structure, policies, priorities and capacity influence, and even limit, the use of scientific evidence to inform decisions. The challenges to making restoration evidence-based are diverse in nature, ranging from poor planning of restoration work, which points to limited appreciation of the need to produce a strong evidence base, to a lack of instruments and incentives to drive the generation, dissemination and use of evidence that spans both the biophysical and social aspects of restoration. These challenges are largely rooted in the conventional way of approaching restoration from individual disciplinary perspectives, thus artificially simplifying and compartmentalizing a naturally complex problem like degradation. I end by proposing transdisciplinarity, which focuses on a holistic world view and the production of knowledge that embraces complexity, as a possible vehicle to help move the practice of restoration towards being evidence-based.
AFRIKAANSE OPSOMMING: Wydverspreide, mens-veroorsaakte agteruitgang van ekostelsels en die gepaardgaande verlies aan biodiversiteit hou 'n direkte bedreiging vir menslike welsyn in. Alhoewel daar geen plaasvervanger is vir 'n gesonde, selfonderhoudende ekostelsel is nie, bied ekologiese restourasie 'n aantreklike en inderdaad onvermydelik, vul waar bewaring alleen nie voldoende ekosisteem integriteit kan ondersteun nie. Restourasie ondergaan tans ‘n revolusie, waar bewys gebaseerde (BG) praktyk 'n opkomende nuwe benadering om die kanse van die suksesvolle bereiking van herstel doelwitte te verhoog. BG praktyk is gebaseer op die idee dat die uitvoering van besluite gebaseer moet word op die evaluering en die gebruik van bewyse van die effektiwiteit van alternatiewe opsies. Die punt van vertrek van hierdie proefskrif is die bewering dat BG praktyk nie noodwendig afhanklik van navorsings bewys hoef te wees nie. Die werk wat hier aangebied word spreek tot die produksie en gebruik van bewyse van effektiwiteit in die restourasie praktyk. Deur die gebruik van tien restourasie programme in Suid-Afrika is die kwaliteit van die bewyse in die praktyk geassesseer. Die drie komponente van bewyse produksie wat geëvalueer is sluit in (i) basislyn toestand meting, (ii) doelwitstelling en (iii) monitering. Resultate toon 'n swak definisie van doelwitte; 'n vooroordeel ten gunste van die gebruik van sosio-ekonomiese doelwitte en aanwysers; meer monitering van insette as die impak; en teenstrydige en kort-termyn monitering van biofisiese aanwysers. Beofenaars het die gebruik van bewys gebaseerde inligting as voldoende beskou, maar 'n paar uitdagings wat verband hou met die beplanning en die beskikbaarheid van bronne is aangehaal as kenmerkende faktore in die gapings wat tans waargeneem word. Ek stel voor dat beoefenaars se persepsie van die huidige bewysbasis praktyk 'n bykomende bedreiging vir die generasie van 'n sterk bewybasis praktyk inhou. Benewens die produksie van bewyse, is die toegang tot bewyse 'n belangrike komponent van die BG praktyk. In die verkenning van hoe bewyse beskikbaar gestel word deur beoefenaars, is dit duidelik dat 'n aansienlike aantal inligting wel bekend is aan beofenaars maar nie maklik toeganklik in gedokumenteerde vorm is nie. Dit beklemtoon die behoefte vir 'n verskuiwing in die praktyk kultuur tot die waardering en beloning van die verspreiding van inligting. 'n Beoordeling van die BG herstel sou onvolledig wees sonder 'n doelbewuste oorweging van sosiale faktore. Ek het dus 'n gevallestudie van 'n indringerplant verwyderings program uitgevoer om vas te stel wat die gebruik van wetenskaplike bewyse in besluitneming aandryf. Ek het opgemerk dat die organisatoriese struktuur, beleid, prioriteite en kapasiteit die gebruik van wetenskaplike bewyse kan beinvloed, en selfs beperk. Die uitdagings om herstelwerk bewys-gebaseerd te maak is uiteenlopend van aard, dit wissel van swak beplanning van herstel werk, wat dui op beperkte waardering van die behoefte om 'n sterk bewyse basis te produseer, 'n gebrek aan instrumente en aansporings vir die generasie van besyse, verspreiding en gebruik van bewyse wat strek oor beide die biofisiese en maatskaplike aspekte van die restaurasie. Hierdie uitdagings is grootliks gegrond op die konvensionele manier van restaurasie wat gebaseer is op individuele dissiplinêre perspektiewe,wat lei tot die kunsmatige simplifiseering van ‘n uiteraand komplekse problem soos agteruitgang. Ek eindig af deur die gebruik van transdissiplinariteit, wat fokus op 'n holistiese wêreldbeskouing en die produksie en kennis van kompleksiteit insluit voor te stel, as 'n moontlike voertuig om die skuif in praktyk van restourasie na n bewys-basis te vergemaklik.

Increasingly large and severe fires across the western United States are creating difficult challenges for land managers. Despite the wide usage of current post-fire hillslope treatments, their effectiveness varies. Some research even shows negative impacts, such as the spread of invasive species.

The use of select post-fire colonizing mosses or “fire moss” is a promising post-fire stabilization treatment and longer-term restoration tool that has never been investigated for use in high severity burned environments. Fire mosses possess traits that make them ideal candidates for restoration purposes such as: universal distribution, desiccation tolerance, high water holding capacity, and soil aggregation ability. Fire mosses also are apparently succeeded by vascular plants. Harnessing the restoration power of fire mosses, finding ways to bring them to additional critical post-fire sites, and hastening their arrival on scene could provide a valuable service not currently being utilized. Our research addresses the basic questions surrounding the effectiveness of fire mosses in post-fire stabilization and restoration since there is no know prior work in this field. Field experiments were conducted to determine if fire moss could be grown on post-fire sites. Results show that inoculation increased moss growth by nine times and moss cover was an order of magnitude greater on high severity burned plots than either moderate or unburned plots. Subsequently, greenhouse experiments were conducted to find optimal growth conditions under which an inoculum supply source could be grown for field application. Results show that greatest moss growth occurred under five and seven day per week watering schedules, with fire moss Bryum argenteum constituting a majority of overall moss growth in the less frequent watering schedules suggesting that this moss would be the best candidate for use in marginal fire moss habitat (lower elevation, drier, and more exposed sites). Additionally, mosses Funaria hygrometrica and Ceratodon purpureus grew more prolifically in sample units with ash, while the opposite was true for Bryum argenteum, suggesting that future research should be conducted on the underlying mechanism. Overall, fire moss showed promise as a plausible restoration material, leading us toward future research given its potential to avoid problems caused by other hillslope treatments.

Although herbaceous communities are important components of floodplain ecosystems, the factors constraining their restoration and post-restoration dynamics are poorly understood. Over the decade following restoration of a 3.2 km reach of the Merced River and floodplain in California, we tracked herbaceous community composition to distinguish floodplain habitats and utilized perturbations from revegetation treatments and post-restoration flooding to generate community assembly rule hypotheses regarding treatment effectiveness and persistence, with a particular interest in native perennials capable of suppressing non-natives over time if undisturbed. Revegetation treatments comprised combinations of sowing a sterile cover crop, sowing native species, and inoculating mycorrhizae. Most surveyed floodplain areas comprised a low terrace characterized by exceptionally droughty soils, relatively deep groundwater, and occasional flooding lasting into summer. Few species could tolerate both flood and drought to this extent, and the flood year community was generally distinct from that in non-flood years. Both communities were dominated by ruderals capable of avoiding stress and re-establishing following disturbance, including many non-native annual grassland species. Only Artemisia douglasiana responded to the treatments, as most seeded native species failed to establish, including those native perennial grasses expected to suppress non-native annuals, while other seeded native species either established adequately from natural dispersal or failed to persist through moderate flooding. Neither the cover crop nor mycorrhizal inoculation had any meaningful effect. Restoration efforts in naturally ruderal-dominated habitats may be better spent allowing natural regeneration, addressing particularly noxious invasives, and identifying or constructing habitats supporting long-lived native perennials.

Although originally developed for population sizes and population growth rates, modern capture-recapture models can estimate demographic rates in complex situations: multistate models for multiple study sites and stage-structured populations, superpopulation entry probability models for recruitment, and multievent models when state assessments are uncertain. However, combinations of these complications, such as recruitment studies with uncertain state assessments, are common, yet no single model has explicitly incorporated all of these elements. Ultimately, these models estimate the same fundamental population process with the same general approach, and we combine them in a generalized hidden process model based upon a simple discrete state and transition population model with Poisson recruitment that can estimate how recruitment and survivorship rates vary with respect to measured covariates from uncertain state assessments for a stage-structured population at multiple sites. Although closely related to the motivating models, the generalized model relaxes the Markov assumption. While we provide the distributions necessary to implement Bayesian data augmentation methods, we also provide an efficient analytical likelihood with a compact parameter space that is applicable in the absence of density-dependent mortality. As a demonstration, we estimate the influence of several covariates on recruitment and survivorship rates from uncertain observations of Salix gooddingii seedlings at different locations along a riparian gradient, and we use simulations to examine variation in the precision of estimated parameters.

In Mediterranean climates, cottonwoods and willows often exhibit high germination and seedling mortality rates, with recruitment occurring primarily in the occasional year when favorable spring floods improve survivorship. However, along the Robinson Reach of the Merced River, both germination and mortality rates appeared to be atypically low. To understand why these rates were so low along this recently restored flow-regulated, gravel-bedded stream, we surveyed Populus fremontii, Salix exigua, and Salix gooddingii, estimated germination and survivorship rates, and examined their correlations with factors expected to constrain recruitment, namely seed release, seed arrival, moist germination beds, light levels, groundwater depth, groundwater recession rates, and shear stress. Germination/initial establishment rates were low due in part to low seed arrival rates. Only Salix gooddingii was abundant enough to model in detail, and while moist germination surfaces increased germination/initial establishment, rates were low overall. Survivorship rates for Salix gooddingii seedlings and for small individuals were not correlated with any examined covariates. Seedlings tolerated moderate competition, and the absence of major scouring, even during 6 year flows, enabled survival at sites with sufficiently shallow groundwater that seedlings were unaffected by groundwater recession rates.

Includes bibliographical references (leaves 109-116).
Facilitation between plants and patch dynamics are two common ecological processes in semi-arid regions. I tested the relevance of these processes to seedling establishment of perennial species on degraded landscapes in Namaqualand, South Africa. The species were grouped into two functional guilds, Mesembryanthema (formerly the family Mesembryanthemaceae, but now part of the Aicoaceae; hereafter Mesemb), which rely on CAM to a variable degree and are shallow rooted, and non-Mesembryanthema (hereafter non-Mesemb) that utilize C3 photosynthesis and have deeper root systems.

Doctor of Philosophy
Department of Division of Biology
John Blair
The feasibility of restoration, which traditionally targets historical conditions, is questionable in the context of global change. To address this, my dissertation investigated (Chapter 2) the patterns of restoration establishment along a chronosequence of restored prairies with respect to nearby remnant prairies, (Chapters 3-4) responses of plant communities in restorations initiated using different methods (levels of species richness and sowing density) to drought, which is projected to increase in frequency, and (Chapters 5-6) the effects of propagule source and variation (mixing among sources) on restoration establishment and the generality of restoration outcomes across variable environments using reciprocal common gardens of multi-species restoration seedings. Chapter 2, published in Restoration Ecology, showed that restoration led to the recovery of desirable characteristics within several years, but restorations utilizing primarily fall-collected seeds likely diminished the representation of early phenology species, so biodiversity may be further enhanced by including early phenology species in seeding mixes. Chapters 3 and 4, published respectively in Ecological Applications and Applied Vegetation Science, examined the establishment of native plant communities after seeding and their responses to experimentally imposed drought. Both high seed mixture richness and high density seeding resulted in greater establishment of native, seeded species compared to low richness and low density treatments, and exotic species were less prevalent in high richness and high density treatments. However, we found little evidence of differential drought resistance, recovery, and resilience among treatments. This result coupled with increases in exotic species following drought suggest that other forms of active management may be needed to produce restored plant communities that are robust to climate change. Chapter 5 (published in Ecosphere) iii and Chapter 6 found that seed source affects individual species establishment, community structure, and productivity. However, there was no consistent advantage for any source, including local sources, across sites or species. This suggests that source effects on single species or effects observed at single locations should not be broadly generalized. Together, this dissertation shows that restoration can recover many characteristics of native prairies and that manipulation of seeding practices (seed mixture richness, seeding density, seed source) influence grassland establishment in terms of productivity, community structure, invasion, and the abundance and survival of individual species.

Thesis (Ph.D.)--University of Missouri-Columbia, 2006.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 6, 2009) Vita. Includes bibliographical references.

Arid areas are often overgrazed and dysfunctional with poor recruitment of desirable species, diminished control over resources and altered soil properties. Restoration ecology re-establishes these valued processes. State-and-transition models summarise knowledge of vegetation dynamics and tools for restoration, and encourage the incorporation of new information. The model developed here for semi-arid woodlands of north-west Victoria highlighted the unknown cause of observed, natural recruitment and the need for a technique, other than direct seeding and handplanting, for enhancing the recruitment of desirable species. I pursued these knowledge gaps for two dominant, woodland trees: Allocasuarina luehmannii and Casuarina pauper. Natural recruitment of juvenile C. pauper was found to be limited and primarily from root suckers. Extensive recruitment of A. luehmannii was shown to be mostly seedlings established following substantial reductions in grazing pressure since 1996. Seedlings were associated with areas devoid of ground flora near a female tree. The importance of competition between seedlings and ground flora, spatial variation in soil moisture and individual variation in the quantity of seed produced deserves further investigation to enhance future restoration success. Root suckers of both C. pauper and A. luehmannii can be artificially initiated, albeit in low numbers and this was found to be a feasible, new tool for restoration. Suckers are preceded by the growth of callus tissue on exposed or damaged, living, shallow roots. Both male and female trees can produce suckers and spring treatments may be more successful. Genetic fingerprinting of mature A. luehmannii and C. pauper trees in six populations did not identify any clonal individuals indicating that recruitment in the past has been from seedlings. Despite this, the high level of gene flow suggests that the impact of introducing small numbers of root suckers into existing populations is unlikely to impact negatively on the population genetics of these species.
Doctor of Philosophy

There is increasing concern among restoration ecologists that using non-local propagules in revegetation schemes may influence the success of grassland restoration. This research programme investigated the importance of propagule provenance in restoration schemes. In particular the work focused on two areas. Firstly, the study investigated the significance of propagule provenance for plant establishment and persistence using Lotus corniculatus as a model species. Secondly, it investigated the practical implications of restricting seed procurement to local sources, using a field trial which assessed the success of limestone grassland re-creation under different treatments. Propagules were collected from two contrasting habitats within each of six regions in the British Isles and a common garden experiment was used to quantify the genetic component of provenance as estimated by plant morphology and fitness. There were differences in survival, growth habit, pubescence, leaf shape, plant size and fecundity between plants grown from seeds sourced from different regions. In addition these populations differed in the extent to which they were damaged by seed herbivores. Differences between plants grown from seed sourced from contrasting habitats were limited to morphology. These findings suggested that populations would be likely to perform differentially in a restoration environment. Both geographical location and the ecological conditions at the seed source should be considered when procuring seeds for a restoration scheme. A field trial was set up to establish whether local propagules exhibited higher fitness than those collected from non-local sources. Propagules were collected from two contrasting habitats in each of fifteen regions. Two restoration environments at a single site were investigated; one was treated with a dressing of topsoil, the other site was untreated bare clay substrate. Differences between populations were measured in terms of both geographical and ecological distance. Results for both sites demonstrated that although there was no home-site advantage in terms of geographical distance, plants from more distant populations were smaller and less fecund in the restoration environment. An investigation into the relationship between ecological distance and plant performance produced different results on the treated and untreated plots. On the treated plot there was no significant relationship but on the untreated plot, plants from more distant populations were larger and more fecund. The contrast in the results obtained for the effect of geographical and ecological distance on performance in the untreated restoration environment is interesting. The enhanced performance of geographically local populations agrees with findings from previous studies. The findings for ecological distance are unexpected based on other work. However, it is postulated that the initial success of non-local populations maybe misleading, as environmental conditions which are infrequent but typical of the area may lead to high mortalities in the longterm. The range of what can be considered local is rarely considered in studies that investigate plant provenance, but work from other areas suggests that there is sufficient variation over small distances to warrant seed collection within 100m. Fine scale phenotypic variation over 200m in populations of L. corniculatus was investigated, however there was no evidence to suggest that seed collection should be restricted to 100m, consequently seeds could be safely collected up to 200m from a restoration site. If seed procurement is to be restricted to local seed then it is possible that the seed application rate and species mix available for a restoration project may be limited. A field trial investigating the effect of different treatments showed that it is possible to establish an appropriate plant community using a low sowing rate. However, that community will be more vulnerable to changes in the environment during the establishment phase and more open to invasion by colonizing species which are likely to be weedy in the first few years. A comparison of two seed mixes showed that a diverse seed mix resulted in an increased diversity and evenness of vegetation. There was no benefit in adding a nurse grass to compensate for a low application rate of local species. In conclusion, although it is an advantage to use seeds of local provenance in restoration schemes, it will be necessary to balance this with the likelihood of successful re-vegetation given the seed available

Tigers (Panthera tigris Linnaeus, 1758) are in danger of extinction. Their populations have declined from ~100,000 to only ~3,000 individuals in a century and their habitat has shrunk to less than 7% of the historic range. Of the five extant tiger subspecies, the Sumatran tiger (Panthera tigris sumatrae Pocock, 1929) is the most seriously threatened. Currently determined as Critically Endangered under IUCN criteria, the Sumatran tiger is likely to become extinct unless effective conservation measures are enacted. Threats to the tiger include habitat destruction, killing due to conflict with humans and livestock, and poaching for illegal wildlife trade. Long-term survival of Sumatran tigers depends largely on the effectiveness of current conservation efforts in every tiger landscape. Successful conservation and management require accurate information on ecology of the species upon which decisions can be based. This study investigated basic ecological aspects of tigers and developed strategies for management and restoration to improve tiger viability in the Central Sumatra landscape. This landscape is comprised of natural forests and plantations managed for timber and agricultural commodities. The first chapter assesses the variation in tiger abundance across forest types in Southern Riau, and over time in Tesso Nilo National Park, all in Central Sumatra. Using camera traps, my team and I systematically sampled five blocks representing three major forest types in the region: peat land, flat lowland, and hilly lowland. I found that tiger abundance varied by forest type and through time. Excluding two sampling blocks where no tigers were photographed, the lowest tiger density was in peat land forest of Kerumutan, and the highest density was in the flat lowland forest of Tesso Nilo. Repeated sampling in the newly established Tesso Nilo National Park documented a trend of increasing tiger density (SE) from 0.90 (0.38) individuals/100 km2 in 2005 to 1.70 (0.66) individuals/100 km2 in 2008. Overall, tiger densities from this study were lower than most previous estimates from other parts of Sumatra. The trend of increasing tiger density in Tesso Nilo, however, suggests that the tiger population could be augmented by protection of habitats that were previously logged and severely disturbed. The second chapter examines the occupancy and habitat-use of the tiger across the major landcover types (natural forest, acacia plantation, oilpalm plantation, rubber plantation, and mixed agriculture). I found that tigers used some plantation areas, although they significantly preferred forests over plantations. In all landcover types, sites with tiger detections had thicker understory cover than sites without tiger detection. Modeling tiger occupancy while recognizing that probability of detection is not always perfect, I found that tiger occupancy covaried positively and significantly with altitude and negatively, but not significantly, with distance-to-forest-cores. Probability of habitat use by tigers covaried positively and significantly with understory cover and altitude, and negatively and significantly with human settlement and landcover rank. The results suggested that with adjustments in plantation management, tigers could use or roam through plantations within the habitat mosaic provided that the plantations had adequate understory cover and low level of human activity. They also could use riparian forests (as corridors) and smaller forest patches (as stepping stones) to travel between the main habitat patches across the forest and plantation landscape. The third chapter investigates the ecological characteristics and possible inter-specific interactions among wild felids, including tigers and smaller cats, based on data collected using systematic camera trapping in combination with information on their natural history. I found that despite overlap in resource needs of the five felid species, each appears adapted to specific environmental conditions allowing coexistence with other felids. The five felid species used statistically different elevations, with the golden cat found to inhabit the highest elevation. Two-species occupancy models showed that only leopard cats were found to co-occur with other felid species more frequently than expected by chance under independence. Species of similar size or eating similar-sized prey generally tended to have low coefficients of temporal activity overlap, suggesting avoidance. Temporal avoidance is likely occurring in three pairs of felids, namely clouded leopards and golden cats, clouded leopards and marbled cats, and marbled cats and leopard cats. Based on the differences in morphological and ecological characteristics, and on patterns of spatial and temporal occurrence, I identified six possible mechanisms by which felids in Central Sumatra maintain coexistence. I discussed the implications of this study for management, focusing on how to balance diversity and abundance of felids. The fourth chapter presents the tiger distribution models as a case study to illustrate the importance of accounting for uncertainty in species distribution mapping. I applied four modeling approaches, differing in how the response variable (tiger presence) is constructed and used in the models. I compared the performance and output of different models based on the relative importance of variables, descriptive statistics of the predictions, cross comparison between models using an error matrix, and validation using tiger presence data collected from independent surveys. All models consistently identified forest area within the grid as one of the most important variables explaining tiger probability of occurrence. Three models identified altitude as another important factor. While the four models were consistent in predicting relatively high probability of tiger occurrence for high elevation forest areas such as Rimbang Baling and Bukit Tigapuluh, they generally had a lower level of agreement in predictions for low elevation areas, particularly the peat land in the northeastern part of the study area. Based on the results of cross evaluation of the predictions among models and validation with the independent data, I considered the occupancy model to be superior to the others. If data collection format permits, I advocate the use of occupancy instead of the other modeling techniques to develop predictive species distribution maps. The last chapter constructs a strategy to restore the tiger population across the ecosystem of Central Sumatra through integration of knowledge on tiger ecology from previous chapters with consideration of the ecological conditions of the landscape in the region. The strategy combines existing knowledge of tiger conservation and regional ecosystem restoration. It recognizes the limitations and challenges of traditional nature protection and considers existing and new opportunities. Emerging opportunities and new mechanisms, such as direct and indirect economic incentives for nature conservation and restoration, are taken into account. These, coupled with increased awareness of the stakeholders, better policies and implementation of good governance, and the willingness and know-how to maintain coexistence with wildlife among the local people, are expected to support and accelerate the recovery of tigers and their ecosystem.
Ph. D.

Thesis (Ph.D.)--Antioch University New England, 2008.
Title from PDF t.p. (viewed November 11, 2009). "A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Environmental Studies at Antioch University New England (2008)."--from the title page. Advisor: Mitchell Thomashow. Includes bibliographical references (p. 289-296).

Arid areas are often overgrazed and dysfunctional with poor recruitment of desirable species, diminished control over resources and altered soil properties. Restoration ecology re-establishes these valued processes. State-and-transition models summarise knowledge of vegetation dynamics and tools for restoration, and encourage the incorporation of new information. The model developed here for semi-arid woodlands of north-west Victoria highlighted the unknown cause of observed, natural recruitment and the need for a technique, other than direct seeding and handplanting, for enhancing the recruitment of desirable species. I pursued these knowledge gaps for two dominant, woodland trees: Allocasuarina luehmannii and Casuarina pauper. Natural recruitment of juvenile C. pauper was found to be limited and primarily from root suckers. Extensive recruitment of A. luehmannii was shown to be mostly seedlings established following substantial reductions in grazing pressure since 1996. Seedlings were associated with areas devoid of ground flora near a female tree. The importance of competition between seedlings and ground flora, spatial variation in soil moisture and individual variation in the quantity of seed produced deserves further investigation to enhance future restoration success. Root suckers of both C. pauper and A. luehmannii can be artificially initiated, albeit in low numbers and this was found to be a feasible, new tool for restoration. Suckers are preceded by the growth of callus tissue on exposed or damaged, living, shallow roots. Both male and female trees can produce suckers and spring treatments may be more successful. Genetic fingerprinting of mature A. luehmannii and C. pauper trees in six populations did not identify any clonal individuals indicating that recruitment in the past has been from seedlings. Despite this, the high level of gene flow suggests that the impact of introducing small numbers of root suckers into existing populations is unlikely to impact negatively on the population genetics of these species.
Doctor of Philosophy

Arid areas are often overgrazed and dysfunctional with poor recruitment of desirable species, diminished control over resources and altered soil properties. Restoration ecology re-establishes these valued processes. State-and-transition models summarise knowledge of vegetation dynamics and tools for restoration, and encourage the incorporation of new information. The model developed here for semi-arid woodlands of north-west Victoria highlighted the unknown cause of observed, natural recruitment and the need for a technique, other than direct seeding and handplanting, for enhancing the recruitment of desirable species. I pursued these knowledge gaps for two dominant, woodland trees: Allocasuarina luehmannii and Casuarina pauper. Natural recruitment of juvenile C. pauper was found to be limited and primarily from root suckers. Extensive recruitment of A. luehmannii was shown to be mostly seedlings established following substantial reductions in grazing pressure since 1996. Seedlings were associated with areas devoid of ground flora near a female tree. The importance of competition between seedlings and ground flora, spatial variation in soil moisture and individual variation in the quantity of seed produced deserves further investigation to enhance future restoration success. Root suckers of both C. pauper and A. luehmannii can be artificially initiated, albeit in low numbers and this was found to be a feasible, new tool for restoration. Suckers are preceded by the growth of callus tissue on exposed or damaged, living, shallow roots. Both male and female trees can produce suckers and spring treatments may be more successful. Genetic fingerprinting of mature A. luehmannii and C. pauper trees in six populations did not identify any clonal individuals indicating that recruitment in the past has been from seedlings. Despite this, the high level of gene flow suggests that the impact of introducing small numbers of root suckers into existing populations is unlikely to impact negatively on the population genetics of these species.
Doctor of Philosophy

Thesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008.
Dispersal plays an essential role in determining the distribution of populations of species, especially species expanding their ranges. Two disciplines are concerned with gaining understanding of spread of species, namely restoration ecology and invasion biology. Con- ceptual understanding of dispersal, its mechanisms and its management is essential to both disciplines. Nevertheless, the disciplines have quite opposite objectives: in restoration ecol- ogy, spread of indigenous species into transformed landscapes is promoted, while invasion biology aims to prevent the (further) spread of alien species into pristine or restored habi- tats. Despite these two opposite objectives of facilitating spread and preventing spread of their respective target species, these disciplines have essentially the same requirements in terms of information needed for restoration. In this thesis, I will present two modelling studies—one looking at the impact of two different seed-feeding alien control agents on the spread of Hakea sericea, the other investigating the recolonisation by Dicerothamnus rhinocerotis of an old field dominated by Cynodon dactylon. Based on these studies, I will draw conclusions for the management in each case. In a second step, I will compare these two seemingly-different studies and draw conclusions on how these two disciplines can learn from each other, and how conclusions drawn and management recommendations developed for the one discipline can be translated for the other. The invasion biology study concluded that seed-feeding biocontrol agents do have a considerable impact on the velocity of the spread of the target species. In addition, management recommendations included the possibility of substituting seed-feeding biocontrol agents with an increased fire frequency where the negative impact on natural vegetation, on the site invaded by the target species, is acceptable. The restoration study concluded that the main impact on the velocity of spread, and the speed of the return of the shrub species onto the old fields, is the availability of micro-sites. A sensitivity analysis showed the even a slight change from 1% to 2% increases the velocity and pattern of spread dramatically. The other parameters playing an important role are the mean rate of establishment and the time span between

The prairie communities that once dominated the landscape of Illinois have been reduced to a fraction of their former extent. Subsequently, considerable effort has been invested in the restoration of these lost communities, yet the comprehensive assessment of restoration success has only recently garnered interest. The objectives of this study were 1) to gauge the success of a prairie restoration project by measuring the components of ecological fidelity (structure/composition, function, and durability), and 2) to determine the factors that influenced success. Nineteen prairie plantings (ranging from two to 19 growing seasons old) at The Nature Conservancy's Nachusa Grasslands preserve were chosen for the assessment. Floristic quality was calculated to assess the composition component of ecological fidelity. Aboveground net primary productivity, soil bulk density, total soil nitrogen and total soil carbon were measured to assess the function component (soil measurements were taken at 0-5 and 5-15 cm depths). Results were compared to benchmark values taken from the literature and from samples of remnant prairies. Durability was determined by comparing measurements across a restoration chronosequence. To further evaluate the prairie plantings and restoration success, non-metric multidimensional scaling ordination was used to compare plantings based on their vegetation composition and soil characteristics (prairie remnants were also included in the comparison based on soil characteristics). Values of Mean C and FQI indicated successful levels among younger plantings, but durability was less successful according to the chronosequence. Seed-mix quality had the greatest influence (positive) on composition success. Aboveground net primary productivity levels were successful and durable overall, however, younger plantings exhibited successful levels of production more consistently than older plantings. Aboveground net primary productivity was most influenced (negatively) by the abundance of the exotic C3 grass genera Poa and Bromus. Functional success based on soil characteristics was limited. Soil bulk density, total nitrogen, and total carbon levels all differed among plantings and remnants at both depths, and evidence of levels recovering toward levels of remnants was not detected. The results of this study indicated that some components of ecological fidelity have been successfully restored, while others have not, and using a high-quality seed mix that resembles the species pool of remnant prairie and limiting the abundance of the dominant native C4 and exotic C3 grasses can improve the restoration of plant composition and ecological function in Illinois prairie plantings. The mixed results underscore the importance of examining more than one component of ecological fidelity when measuring success. Long-term monitoring is also recommended for evaluating restoration durability, especially for detecting changes among soil properties over time.

Grasslands are known to have been an important ecosystem in the Illinois landscape prior to European settlement. They have been severely impacted by changes in land use such as the conversion of native grasslands to agricultural land for the production of crops and livestock. Grassland ecosystems are known to provide several essential ecosystem functions that are important for the maintenance of the ecosystem and for human survival. Some of the ecosystem functions associated with grasslands include: nutrient cycling, carbon sequestration, and the cleansing of environmental contaminants from water or soil. As grasslands are converted to agricultural use, their ability to perform these ecosystem functions are greatly impaired or lost completely. Due to their recognized importance, grassland restoration projects have been given high priority by conservationists and governmental agencies around the world. Some grassland restorations aim to restore the native vegetation including the great species richness that grasslands, and prairie ecosystems in particular, are known for. Other projects, like the Conservation Reserve Program (CRP), aim to restore one of the vital ecosystem functions that grasslands provide. The measure of success for a grassland restoration has largely been evaluated using species composition and indices of species richness and evenness. These types of measurements do not directly assess the ability of a restoration site to perform the ecosystem functions of a native grassland. The aim of this study is to determine if ecosystem function is recovered over time since restoration. This will be accomplished using a chronosequence of grassland restorations at the Nature Institute in Godfrey, IL ranging from 1 year to 25 years since restoration. Several indicators of ecosystem functioning will be assesses at each site including: soil bulk density, soil organic matter, and peak standing crop. The differences in these characteristics among the sites were analyzed by one-way ANOVA followd by Tukey’s HSD test if significant. All properties were analyzed using linear regression to assess their fit to a linear model. Soil bulk density was found to moderately but significantly decrease in response to time since restoration (p = 0.0049) indicating a recovery from soil compaction and improved soil structure. Differences were detected in soil organic matter among the sites, but no linear trend in response to time since restoration was detected. Similarly with peak standing crop, differences were detected among the sites, but no linear trend with time since restoration. The lack of a predictable recovery in soil characteristics over time was attributed to differences in historical land use. In order to strengthen this study in the future, analysis of a remnant prairie and older restoration sites should be examined.

Since European settlement, clearing for agriculture, changes in hydrology, and urbanization have reduced the coverage of bottomland forest (BLF) in the Upper Mississippi Valley (UMV) by 46%. Recently, emphasis has been placed on restoring BLF, which provides vital ecosystem services (e.g., enhanced water quality, nutrient cycling, and wildlife habitat). Beginning in 1998, the US Army Corps of Engineers has restored BLF on many sites in the UMV, ranging in area from less than 1 ha to 120 ha. Root production method (RPM^®) seedlings of three species of bottomland oaks and pecan have been planted to rapidly establish large-seeded species that are not regenerating under current conditions, with the expectation that light-seeded species (e.g., silver maple, green ash, eastern cottonwood, elm) will colonize passively. A chronosequence of nine restoration sites, ranging in age from 1 to 23 yr since planting, and two mature BLF reference sites was used to assess restoration success. Five 0.1-ha circular plots were randomly located at each site. Planted trees and natural recruits with a diameter at breast height (DBH) greater than or equal to 2.5 cm were identified, tagged, and their basal diameter, DBH, and height were measured. Density of shrubs was assessed in belt transects with a total area of 100 m² and cover of herbaceous species was estimated in twenty 0.5 m2 quadrats. Tree variables by species (mean basal diameter, mean height, density, and dominance) and community variables (richness and Simpson diversity of each stratum, total tree dominance, total shrub density, total herbaceous cover and the percent exotic herbaceous species cover) were calculated at the plot scale. Trajectories of change in tree size and community structure were examined using generalized linear modeling, relative to their values in reference sites. Tree height and diameter increased with time since restoration for all species. Quercus palustris, Q. macrocarpa, and Q. bicolor are all on track to achieve dimensions typical of mature BLF within 27 to 37 yr since planting. However, the dominance models for these trees show general declines which may indicate decreasing survivorship among planted trees and no recruitment of new seedlings. Pecan has suffered high mortality and without replanting it will be underrepresented in the restored forest. Tree dominance, richness, and diversity peaked and then decreased. Both total shrub density and total herbaceous cover showed no trend with time, although diversity of both shrubs and herbaceous vegetation slightly increased. Comparison with reference sites suggest that the shrub density, although there is no trend with time, is still in line with reference plot values. Exotic cover peaked between 10 to 15 years and began to decline to levels similar to reference plots. Overall, the results indicate some restoration success (tree growth rates, shrub diversity, herbaceous richness and diversity, and declines in exotic species cover) but suggest that replanting will be necessary in most sites to overcome mortality due to prolonged flooding and other factors (e.g. white-tailed deer browsing, inhibition of tree recruits by dense grass cover). Accurate mortality data for planted tree species is necessary to evaluate and improve the success of future USACE restorations. Ideally, a subset of trees should be tagged immediately after planting and these trees should be monitored at regular intervals. Frequently updated records will allow the USACE to make site-to-site management adjustments.

Over the last decade, restoration ecology has been considered a new paradigm for dealing with many of the environmental problems of river systems. It is also recognized that management decisions have a greater chance of being successful if they are based on a thorough understanding of a concept or a plan. A review of current studies on river restoration and river restoration planning revealed that managers and scientists have put a substantial emphasis on ecological science and technology in restoration, while many sociopolitical and economic elements have been de-emphasized Besides this, understanding and experiences of river restoration, especially those of river managers and communities, is not well known so far. This study commenced with the development of a framework for river restoration planning, based on a review of current knowledge of river restoration and planning processes. The framework was then used as an instrument to be compared with the understanding and experiences of river managers in two different countries. The aim of this study was to highlight the differences in acceptability of river restoration and river restoration planning between two different river systems in two different countries, and develop a framework for river restoration planning that includes these differences. Using a heuristic inquiry, administrators responsible for two rivers, the Kalgan River in southwest Western Australia and the Liao River in northeast China, were interviewed to test if managers have comparable understandings of river restoration. This study revealed that the understanding of the river restoration concept among never managers who participated in this research is influenced by socio-political, economic and ecological perspectives. For example, in Australia, managers see river restoration according to the kind of ecological benefits people will derive from it. To maintain the sustainable development of the river system is the main goal of river restoration In contrast. In China, river managers would like to put more efforts on maintaining the balance between social, economic and ecological development, although, in the short term, pollution control is the first crucial step for river management. The study also indicated that planning is influenced by different understandings of the concept of river restoration, by the existing administrative structures for river management, and by public participation in river management planning. For example, public participation plays an important role in river restoration planning in Australia, while in China, public participation was not considered appropriate or practical in the formulation of a plan even though more and more managers recognize its need and significance. The final result of this study, a framework for river restoration planning, will supply some basic management guidelines for river managers. Future research can be conducted by using data from a project river to put the results of this study into practice, where case studies can be examined to test the robustness of the framework.

Mountainous regions comprise more than 30% of the world's terrestrial biomes and are valued for livestock forage, mineral and timber assets and recreation opportunities. Disturbance has resulted in major ecological changes in high elevation ecosystems, including vegetation loss, soil compaction, and reduced soil organic matter (SOM). Restoring high elevation disturbed sites has proven challenging for many years, possibly because of our limited knowledge of disturbance effects on belowground biota, and the ecosystem functions they facilitate. This research compares soil physiochemical and biological properties on disturbed, undisturbed and restored subalpine soils in two national forests in Montana and Washington. Soil physiochemical properties measured include soil moisture, bulk density, SOM, soil nitrogen (N; both total and plant available), phosphorous (P) and potassium (K). Biological processes measured include mycorrhizal infectivity potential (MIP), decomposition, enzyme activity, substrate induced respiration (SIR) and N mineralization. Soil moisture and SOM were significantly lower, while bulk density was higher, on disturbed sites. Total nitrogen (N) was lower on disturbed sites, while NO₃ - and NH₄ + differed only between geographic locations. MIP was low overall and did not differ between disturbance. Decomposition rates did not differ between disturbance after 3, 12 or 24 months. Enzyme activity differed with disturbance and location, with significantly lower activity on disturbed sites for 1 substrate, while nearly significant lower activities for 4 out of 8 substrates measured. SIR differed with disturbance and location, with lower responses on disturbed sites for 6 of 26 substrates. Soil physiochemical and biological characteristics are affected by disturbance and location, however results vary between the parameters measured. This suggests ecosystem components, including soil physiochemical and biological properties are decoupled, responding individualistically to disturbance and restoration.

Thesis (Ph.D.)--Antioch University New England, 2010.
Title from PDF t.p. (viewed July 22, 2010). "A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Environmental Studies at Antioch University New England (2010)."--from the title page. Advisor: James Jordan, Ph.D. Includes bibliographical references (p. 97-104).

La recuperació d’espais fluvials és una activitat que ha anat en augment en els darrers anys però no disposava de mètodes d’avaluació que n’orientessin el disseny. L’objectiu de la tesi ha estat explorar la pràctica de la restauració fluvial a Catalunya, desenvolupant alhora protocols que contribueixin a la seva sistematització. Així, s’ha elaborat una metodologia basada en l’avaluació dels continguts dels projectes de restauració fluvial (el Protocol APR). Aquest s’ha validat aplicant-lo a una mostra de 40 projectes de restauració fluvial, fet que ha permès analitzar aquesta activitat a Catalunya entre 1999 i 2011. L’anàlisi ha posat de manifest mancances importants en el desenvolupament de plans de seguiment dels projectes. Com a conseqüència, s’ha desenvolupat una metodologia ad hoc que permet dissenyar programes de seguiment de l’èxit dels projectes (el Protocol SPR). Complementàriament, donat que les pròpies actuacions dels projectes poden ocasionar impactes sobre l’ecosistema fluvial, s’ha investigat l’efecte durant la fase d’execució d’una de les actuacions més comunes en els projectes de restauració catalans: el tractament del canyar (Arundo donax). Per això, s’ha testat l’efecte de l’aplicació de l’ús d’un herbicida de base glifosat sobre la comunitat de macroinvertebrats (tant a nivell estructural com funcional). Les fites de la recerca s’han acomplert i s’espera que contribueixin a l’avenç de la restauració fluvial, en la mesura que els agents que participen en els projectes segueixin promovent-los, tot compartint els seus resultats i experiències.
River restoration has become an increasing activity in recent years, but no assessment methods existed to guide restoration projects design. The aim of the thesis was to explore the practice of river restoration in Catalonia and to develop several protocols that contribute to its systematization. Thus, a methodology based on the evaluation of the contents of river restoration projects (APR Protocol) has been elaborated. This has been validated by its application to a sample of 40 river restoration projects, allowing to analyze this activity in Catalonia between 1999 and 2011. The analysis revealed significant shortcomings in monitoring plans of restoration projects. As a consequence, an ad hoc-methodology which enables practitioners to design programs to follow up project success (SPR Protocol) has been developed. Additionally, since project actions by themselves may cause impact on the river ecosystem, the effect during the execution phase was investigated for one of the most common measures in Catalan restoration projects: the elimination of giant reed (Arundo donax). To this end, the effect of the application of an herbicide with glyphosate as active ingredient was tested over the macroinvertebrate community (both at the functional and structural levels). The goals of this research have been met and it is expected that they will contribute to the advance of river restoration, as the parts involved continue promoting river restoration projects, and sharing their experiences and results.

Land use change to meet economic and societal demands has negatively impacted the current state of our world's ecosystems and biodiversity. The alarming rate of landscape change and degradation has prompted ecologists to conserve intact areas and restore historical habitats in the hopes of mitigating the potential damage. As a result, restoration ecology was developed and has grown dramatically within the past couple decades. Historically, the Mississippi Alluvial Valley, provided services such as water enhancement and nutrient cycling, and the characteristic bottomland hardwood forests dominated the land cover and were suitable habitat for many organisms, especially neotropical migrants. As the Upper Mississippi Alluvial Valley was converted into agricultural fields and locks and dams were installed, many neotropical migrants had steady population declines. More recent surveys have noted that approximately two-thirds of the neotropical migrants have been declining for the past half-century. For the past two decades, the U.S. Army Corp of Engineers (USACE) has been responsible for the restoration of bottomland hardwood forests in the Upper Mississippi Valley. Using birds as model organisms, this project assessed the restoration success of this site by (1) comparing avian richness, diversity, and density among a chronosequence of forest restoration age classes to determine any significant differences in species assemblage in the chronosequence and (2) creating a predictive habitat model that assists in the formulation of appropriate recommendations for restoration planning and management in the future. I hypothesize that species richness and diversity is highest at intermediate sites since they will have habitat characteristics of both grasslands and forests and that my habitat models identifies structural variables, such vegetation height, and tree height and ground cover as significant determinants of avian presence. Our study included a chronosequence of nine restoration sites and two references in which bird surveys and vegetation surveys were completed. Avian surveys consisted of 25-m fixed radius point counts at five plots per site. Sites were visited three times for the spring and fall data collections. Spring data will continue May 2014 due to unusual flooding conditions. Within the 25-m radius, a 17.84-m radius vegetation plot was created. Tree species, tree health variables, diameter at breast height (DBH), and abundance were recorded, and the tree was tagged. Shrub stem count data was recorded in four belts within each vegetation plot, with the condition that a shrub is at least 1-m in height. The plot was divided into four belts, and five quadrats of 0.5 m2 were formed along each belt to record forb and grass cover and litter depth. Species richness, Antilog Shannon-Weiner's Diversity Index, and Simpson's Diversity Index was calculated, and the vegetation data was used in the predictive habitat modeling. I recorded 52 bird species during the spring and 79 bird species during that fall that were within the 25-m radius. Bird species richness and diversity differed among the sites, and richness and diversity generally increased as the age of the site increased. Grassland and shrubland birds did not have any significant trends for vegetation parameters. However, most open woodland birds had a significant association with DBH, and a majority of forest birds had significant associations with tree height and crown size. The observed richness and diversity values contradict several studies but may be attributed to the productivity rate of the sites chosen. Density estimates can also be enhanced through new surveying methods which would address detectability issues for naturally skittish birds. Future restoration efforts should include the planting of fast-growing trees and shrubs in order to increase structural diversity at faster rates. In addition, more sites should be acquired and restored in order to create close patches for neotropical migrants to facilitate travel. Continuing efforts in restoration and appropriate management should emphasize the causes of declines for land birds and identify them early enough to develop an appropriate management plan.

Cold-water coral (CWC) habitats dwell on continental shelves, slopes, canyons, seamounts, and ridge systems around the world’s oceans, from 50 m to depths up to 4000 m. CWC species provide heterogeneous habitats supporting a myriad of associated fauna and form highly diverse CWC reefs and CWC gardens. Main threats, currently impacting CWC ecosystems come from anthropogenic stressors, such as fishing activities, oil and gas exploitation and the incipient mining activity. Likewise, climate change, causing changes in the water column, is also affecting these ecosystems. Life-history traits of CWC species (long lifespans, slow growth and limited recruitment) make them very vulnerable to current and potential threats. Given their limited recovery capacity, interest to preserve and restore CWC ecosystem is steadily growing. The creation of Marine Protected Areas and active ecological restoration actions are nowadays the best management tools to conserve native ecosystems and represents an opportunity to revert the anthropogenic damage that has already taken place. Through passive (natural regeneration after the cessation of stressors) and active (human interacts with biotic and/or abiotic ecosystem features) approaches, restoration activities seek to accelerate the recovery of ecosystem structure and functioning relative to a reference model. Contrarily to terrestrial and shallow-water marine ecosystems, ecological restoration in intermediate (50 – 200 m) and deep marine (> 200 m) environments has received lesser attention. To date, only few restoration actions at local scales have been carried out at those depths, mainly due to technical and economic limitations which questions its wide application. Scaling-up restoration actions and make them affordable are the main present challenges for CWC restoration. In this sense, in order to move forward towards the conservation of intermediate and deep-sea ecosystems, the general aim of the present thesis is to assess the impact of fishing activity on CWC gardens as well as to explore the feasibility of novel active ecological restoration techniques. All the work performed during this thesis has been carried out at the Cap de Creus marine area (North-Western Mediterranean Sea), specifically at the continental shelf (60 – 130 m), where gorgonians, sponges, and sea pen species form CWC gardens supporting a variety of mobile associated fauna. The target species is the yellow gorgonian Eunicella cavolini (Koch, 1887) which dominate in the area forming density patches. In the first chapter, the impact of artisanal fishing was quantified to evaluate the threat of this activity on CWC gardens and to provide essential information to mitigate such impact. The rest of chapters (2, 3 and 4) evaluated, for the first time, the viability to actively restore degraded E. cavolini populations. Specifically, in the second chapter, gorgonians obtained from bycatch (accidentally caught of non-target species) of local artisanal fishers, were transplanted to artificial structures deployed on the continental shelf (805 m). This pilot study demonstrated, for the first time, the high survival of E. cavolini transplants. Following, and going one step forward, in the third chapter, field experiments and modeling approaches were combined to develop and technically validate an innovative large-scale and cost- effective restoration method for CWC gardens. Successful results evidenced the feasibility of recovering bycatch E. cavolini and returning them to their natural habitat with this novel method so-called “badminton method”. Finally, in the fourth and last chapter, a large- scale restoration action of E. cavolini populations was carried out in collaboration with local artisanal fishers during two consecutive fishing seasons by applying the technique previously developed. A large number of gorgonians (460 colonies) were successfully reintroduced and survived at the end of the action (2 years) at 80-100 m depth. The results suggested an initial establishment of a new gorgonian population, which will potentially evolve toward a comparable natural population in terms of size and spatial structure, if natural recruitment also occurs. Moreover, an economic evaluation was performed, also confirming the cost efficiency of this method aimed at enhancing the recovery of impacted CWC gardens. The lack of knowledge of some key ecological processes of CWC ecosystems as well as the technical limitations hinder a complete evaluation of restoration efforts performed. However, this thesis represents a promising improvement for the conservation and recovery of CWCs that could be extended to other areas and regions.
Els coralls d’aigua freda habiten en les plataformes continentals, talussos, canyons, muntanyes submarines i dorsals oceàniques d’arreu del món, des de 50 a 4000 metres de profunditat. Les espècies de coralls d’aigua freda creen hàbitats heterogenis que donen suport a una infinitat de fauna associada i formen esculls i boscos de coralls altament diversos. Les principals amenaces que actualment impacten aquests ecosistemes de coralls d’aigua freda son d’origen antròpic, com ara l’activitat pesquera, l’explotació de petroli i gas i l’incipient explotació minera. Així mateix, el canvi climàtic, el qual provoca canvis en la columna d’aigua, també està afectant aquests ecosistemes. Les característiques vitals dels coralls d’aigua freda (longevitat, creixement lent i reclutament limitat) els fan molt vulnerables a les amaces tan actuals com futures. Atesa la seva limitada capacitat de recuperació, l’interès per preservar i restaurar els ecosistemes de coralls d’aigua freda està en constant creixement. La creació d’àrees marines protegides i les accions restauració ecològica activa són avui en dia les millors eines de gestió per conservar ecosistemes autòctons i representen una oportunitat per revertir els danys antròpics que ja han tingut lloc. A través d’enfocaments passius (regeneració natural després del cessament del impacte) i actius (l’ésser humà interacciona amb les característiques biòtiques i/o abiòtiques de l’ecosistema), les activitats de restauració busquen accelerar la recuperació de l’estructura i funcionament dels ecosistemes en funció a un model de referència. Contràriament als ecosistemes terrestres i d’aigües someres, la restauració ecològica enfocada a ambients marins intermedis (50–200 m) i profunds (> 200 m) ha rebut menor atenció. Fins ara, a aquestes profunditats només s’han dut a terme algunes poques accions de restauració a escala local, principalment a causa de limitacions tècniques i econòmiques que qüestionen la seva àmplia aplicació. Els principals reptes actuals per la restauració de coralls d’aigua freda són incrementar l’escala espacial de les accions de restauració i fer-les econòmicament més assequibles. En aquest sentit, per avançar en la conservació dels ecosistemes de fons intermedis i profunds, l’objectiu general de la present tesi és avaluar l’impacte de l’activitat pesquera sobre els boscos de coralls d’aigua freda i explorar la viabilitat de innovadores tècniques de restauració activa. Tot el treball realitzat en aquesta tesi s’ha dut a terme a la zona marina del Cap de Creus (Nord-Oest del mar Mediterrani), contretament a la plataforma continental (60 – 130 m) on espècies de gorgònies, esponges i plomalls formen boscos de coralls d’aigua freda donant suport a una gran varietat de fauna mòbil associada. L’espècie objectiu és la gorgònia groga Eunicella cavolini (Koch, 1887) la qual domina a la zona formant denses agregacions. En el primer capítol, es va quantificar el impacte de la pesca artesanal per avaluar l’amenaça d’aquesta activitat sobre els boscos de coralls d’aigua freda i proporcionar informació essencial per mitigar aquest impacte. La resta de capítols (2, 3 i 4) van avaluar, per primera vegada, viabilitat de restaurar activament les poblacions degradades de E.cavolini. Especificament, en el segon capítol és van trasplantar les gorgònies capturades accidentalment pels pescadors artesanals de la zona, a estructures artificials fondejades a la plataforma continental (85 m). Aquest estudi pilot va demostrar per primera vegada l’alta supervivència dels transplantaments d’E.cavolini. Seguidament, i anant un pas més enllà, al tercer capítol es van combinar experiments de camp i modelització per desenvolupar i validar tècnicament una nova tècnica de restauració per als boscos de coralls d’aigua freda, a gran escala i econòmicament assequible. Els exitosos resultats van evidenciar la viabilitat de recuperar les colònies de E.cavolini capturades accidentalment i retornar-les al seu hàbitat natural amb aquesta innovadora tècnica , anomenada “el mètode bàdminton”. Finalment, al quart i últim capítol, es va dur a terme una acció de restauració de les poblacions de E.cavolini a gran escala, amb la col·laboració de pescadors artesanals de la zona i al llarg de dues temporades de pesca consecutives aplicant la tècnica desenvolupada anteriorment. Un gran nombre de gorgònies (460 colònies) van ser re-introduïdes amb èxit i van sobreviure al final de l’acció (2 anys) a 80-100 m de profunditat. Els resultats van suggerir l'establiment inicial d'una nova població gorgònies, que potencialment evolucionarà cap a una població natural comparable en termes d’estructura de talles i estructura espacial, sempre i quan es produeix també un reclutament natural. D'altra banda, es va fer una avaluació econòmica, que va confirmar la rendibilitat d'aquest mètode dirigit a millorar la recuperació dels boscos de coralls d’aigua freda impactats. El desconeixement d'alguns processos ecològics claus en els ecosistemes de coralls d’aigua freda, així com les limitacions tècniques, dificulten una avaluació completa dels esforços de restauració realitzats. Tanmateix, aquesta tesi suposa una millora prometedora per a la conservació i recuperació dels coralls d’aigua feda, que es podria estendre a altres zones i regions.

Grasslands are considered to be the most endangered terrestrial ecosystem in the world. In the United Kingdom, substantial losses in unimproved grasslands and the abandonment of traditional grazing has resulted in the decline of ecosystem services, such as pollination. A plant trait-based approach was conducted to study the community ecology and restoration of temperate grasslands, with a focus on the convergence/divergence patterns in response to environmental and management factors, and how these scale to the provision of ecosystem processes and services –biomass production and livestock. The role of seven plant traits, obtained from the TRY-database, was investigated using the botanical data of the National Vegetation Classification, the Park Grass Experiment and the North Wyke Farm Platform. Trait-based analyses were conducted on the latter two to investigate the provision of biomass production and livestock production. A microcosm experiment was conducted to test the effects of agricultural soil legacies and restoration seed mixture on the reassembly of grassland communities, and their associated functional structure and composition. It was found that the seven traits investigated were independent and countered the conceptualisation of ecological axes of specialisation and ecological strategies. The type of fertiliser used to improve grasslands was found to be a significant factor driving the convergence/divergence patterns of temperate grassland communities, together with grazing. Biomass production was found to be best explained by statistical models incorporating climate and environmental factors, community-weighted means and different facets of functional diversity. In essence, environmental and management pressures resembling intensely managed, especially with nitrate-based fertilisers, temperate grasslands and an exploitative community best supported greater amounts of high quality biomass. Livestock production was found to be best explained by the Functional Diversity Hypothesis: higher yields from cattle and sheep were found from diverged grazing pastures. A trade-off between cattle quantity and quality was also highlighted. Agricultural soil legacies were found to greatly hinder the progression towards vegetation and functional restoration targets, producing ruderal communities dominated by weak competitors and opportunistic weedy plant species. The work has important implication for the management and restoration of grassland communities.