Long Term Ecological Research Research Papers (original) (raw)

This is a collaborative portfolio of art and writing from Tumamoc Hill including work by Paul Mirocha, Eric Magrane, Barbara Terkanian, Monique Soria, D.L. Coleman, Meredith Milstead, and Kathleen Koopman. The introduction, titled "A... more

This is a collaborative portfolio of art and writing from Tumamoc Hill including work by Paul Mirocha, Eric Magrane, Barbara Terkanian, Monique Soria, D.L. Coleman, Meredith Milstead, and Kathleen Koopman.
The introduction, titled "A Context for Arts on Tumamoc," by Mirocha and Magrane, begins:
Early on a recent May morning, artist Meredith Milstead set up her easel outside of the historic Desert Lab buildings on Tumamoc Hill and proceeded to paint the scene before her over a twelve-hour period, completing one painting per hour. A study of color and time, the act of making these paintings echoes the historical research on Tumamoc. Much of what is known about deserts comes from Tumamoc Hill, either through research at the site itself or through the impressive list of those—a who's who of desert ecologists—who have worked at the Hill over the years. It's not a stretch to claim that the modern field of ecology owes much of its beginning to the Carnegie Desert Botanical Laboratory established on Tumamoc Hill in 1903. Long-term study plots set up by these early ecologists comprise the longest-running vegetation-monitoring program in the world. That some of the current activity on the Hill is in the form of art or poetry is a reflection of the growing awareness that scientific and artistic ways of knowing are not in opposition but can be, rather, complementary to each other. In a time when climate change has us facing increasing temperatures, drought, and wildfire here in much of the Southwest, and when increased acknowledgment that the disciplinary silos that have built up over the last couple of centuries are not up to facing such big questions alone, it is fitting that Tumamoc Hill is one of the sites that has embraced the role that artists and writers may play in the present, an epoch that many have begun to call the Anthropocene.

SummaryThe north-west European population of Bewick’s Swan Cygnus columbianus bewickii declined by 38% between 1995 and 2010 and is listed as ‘Endangered’ on the European Red List of birds. Here, we combined information on food resources... more

SummaryThe north-west European population of Bewick’s Swan Cygnus columbianus bewickii declined by 38% between 1995 and 2010 and is listed as ‘Endangered’ on the European Red List of birds. Here, we combined information on food resources within the landscape with long-term data on swan numbers, habitat use, behaviour and two complementary measures of body condition, to examine whether changes in food type and availability have influenced the Bewick’s Swan’s use of their main wintering site in the UK, the Ouse Washes and surrounding fens. Maximum number of Bewick’s Swans rose from 620 in winter 1958/59 to a high of 7,491 in winter 2004/05, before falling to 1,073 birds in winter 2013/14. Between winters 1958/59 and 2014/15 the Ouse Washes supported between 0.5 and 37.9 % of the total population wintering in north-west Europe (mean ± 95 % CI = 18.1 ± 2.4 %). Swans fed on agricultural crops, shifting from post-harvest remains of root crops (e.g. sugar beet and potatoes) in November and...

Abstract: Biodiversity is presently a minor consideration in environmental policy. It has been regarded as too broad and vague a concept to be applied to real-world regulatory and management problems. This problem can be corrected if... more

Abstract: Biodiversity is presently a minor consideration in environmental policy. It has been regarded as too broad and vague a concept to be applied to real-world regulatory and management problems. This problem can be corrected if biodiversity is recognized as an end in itself, and if measurable indicators can be selected to assess the status of biodiversity over time. Biodiversity, as presently understood, encompasses multiple levels of biological organization. In this paper, I expand the three primary attributes of biodiversity recognized by Jerry Franklin — composition, structure, and function—into a nested hierarchy that incorporates elements of each attribute at four levels of organization: regional landscape, community-ecosystem, population-species, and genetic. Indicators of each attribute in terrestrial ecosystems, at the four levels of organization, are identified for environmental monitoring purposes. Projects to monitor biodiversity will benefit from a direct linkage to long-term ecological research and a commitment to test hypotheses relevant to biodiversity conservation. A general guideline is to proceed from the top down, beginning with a coarse-scale inventory of landscape pattern, vegetation, habitat structure, and species distributions, then overlaying data on stress levels to identify biologically significant areas at high risk of impoverishment. Intensive research and monitoring can be directed to high-risk ecosystems and elements of biodiversity, while less intensive monitoring is directed to the total landscape (or samples thereof). In any monitoring program, particular attention should be paid to specifying the questions that monitoring is intended to answer and validating the relationships between indicators and the components of biodiversity they represent.Resumen: La biodiversidad es hasta ahora una consid-eración menor en lapolitica ambiental. Se ha visto como un concepto demasiado amplio y vago para ser aplicado en las regulaciones y el manejo de los problemas del mundo real. Este problema se puede corregir si la biodiversidad es reconocida como unfinporsi misma, y si se pueden seleccionar indicadores cuantificables para determinar el estado de la biodiversidad a través del tiempo. La biodiversidad, como se entiende actualmente comprende múltiples niveles de organización biológica En esta disertación, extiendo los tres atributos primarios de la biodiversidad reconocidos por Jerry Franklin — composición, estructura y función — dentro de unajerarquia que encaja a incorpora los elementos de cada uno de los atributos en cuatro niveles de organización: paisaje regional, ecosistemas de las comunidades, población de especies y genética Los indicadores de cada atributo en los ecosistemas terrestres, en los cuatro niveles de organización, son identificados para propósitos de monitoreo ambiental. Los proyectos para el monitoreo de la biodiversidad se beneficiarian de una unión directa con la investigación ecológica a laqo plazo y de un compromiso paraprobar hipótesis relevantes a la consmacidn de la biodiversidact. Un lineamiento general es proceder de arriba para abajo, empezando con una escala-burda de inventario de los patrones del paisaje, de la vegetación, de la estructura del hábitat y de la distribución de ls especies, después super-poner los datos sobre niveles de presión para identificar las areas da alto riezgo y de empobrecimiento. La investigación intensive y el monitorio peude ser dirigido a los ecosistemas de alto riezgo y a los elementos de la biodiversidad, mientras que un monitoreo ménos intenso se puede dirigir a1 total del paisaje (O a muestras del mismo). En cualquier programa de monitoreo, se debe de poner atención especial a1 estar espe-cificando las preguntas que el monitoreo pretende resolver y al estar validando las relaciones entre los indicadores y los componentes de la biodiversidad que representen.

Ecosystem monitoring networks aim to collect data on physical, chemical and biological systems and their interactions that shape the biosphere. Here we introduce the Australian SuperSite Network that, along with complementary facilities... more

Ecosystem monitoring networks aim to collect data on physical, chemical and biological systems and their interactions that shape the biosphere. Here we introduce the Australian SuperSite Network that, along with complementary facilities of Australia's Terrestrial Ecosystem Research Network (TERN), delivers field infrastructure and diverse, ecosystem-related datasets for use by researchers, educators and policy makers. The SuperSite Network uses infrastructure replicated across research sites in different biomes, to allow comparisons across ecosystems and improve scalability of findings to regional, continental and global scales. This conforms with the approaches of other ecosystem monitoring networks such as Critical Zone Observatories, the U.S. National Ecological Observatory Network; Analysis and Experimentation on Ecosystems, Europe; Chinese Ecosystem Research Network; International Long Term Ecological Research network and the United States Long Term Ecological Research Network. The Australian SuperSite Network currently involves 10 SuperSites across a diverse range of biomes, including tropical rainforest, grassland and savanna; wet and dry sclerophyll forest and woodland; and semi-arid grassland,woodland and savanna. The focus of the SuperSite Network is on using vegetation, faunal and biophysical monitoring to develop a process-based understanding of ecosystem function and change in Australian biomes; and to link this with data streams provided by the series of flux towers across the network. The Australian SuperSite Network is also intended to support a range of auxiliary researchers who contribute to the growing body of knowledge within and across the SuperSite Network, public outreach and education to promote environmental awareness and the role of ecosystem monitoring in the management of Australian environments.

Many social-ecological system(SES)-based approaches have been proposed to address environmental problems. Most social-ecological frameworks developed to date, however, lack clear operational linkages between humans and nature to... more

Many social-ecological system(SES)-based approaches have been proposed to address environmental problems. Most social-ecological frameworks developed to date, however, lack clear operational linkages between humans and nature to efficiently guide SESs toward resilience. A conceptual framework designed to be operational is therefore necessary, as well as a network of research platforms with which to apply it. We defined explicit coupling processes that can be used as leverages to pilot an SES toward sustainability. We proposed to formalize an SES as a dynamic entity composed of two coupling interfaces, i.e., adaptive management and ecosystem services, both set within a landscape context to provide an actionable framework. These interfaces describe the way various actors, including scholars, benefit from and manage complex and changing interactions between the biophysical and social templates. Understanding the key processes underlying the interaction dynamics, especially those leveraging adaptive management processes, would help identify adaptive pathways for practices and collective actions, provide a crucial knowledge base for policy makers, and foster operationality as a requisite of an SES research agenda. Using several examples, we explained why long-term social-ecological research platforms provide an ideal operational network of research infrastructures to conduct place-based action-orientated research targeting the sustainability of SESs.

The authors summarize the main findings of the Florida Coastal Everglades Long-Term Ecological Research (FCE-LTER) program in the EMER, within the context of the Comprehensive Everglades Restoration Plan (CERP), to understand how regional... more

The authors summarize the main findings of the Florida Coastal Everglades Long-Term Ecological Research (FCE-LTER) program in the EMER, within the context of the Comprehensive Everglades Restoration Plan (CERP), to understand how regional processes, mediated by water flow, control population and ecosystem dynamics across the EMER landscape. Tree canopies with maximum height <3 m cover 49% of the EMER, particularly in the SE region. These scrub/dwarf mangroves are the result of a combination of low soil phosphorus (P < 59 μg P g dw−1) in the calcareous marl substrate and long hydroperiod. Phosphorus limits the EMER and its freshwater watersheds due to the lack of terrigenous sediment input and the phosphorus-limited nature of the freshwater Everglades. Reduced freshwater delivery over the past 50 years, combined with Everglades compartmentalization and a 10 cm rise in coastal sea level, has led to the landward transgression (∼1.5 km in 54 years) of the mangrove ecotone. Seasonal variation in freshwater input strongly controls the temporal variation of nitrogen and P exports (99%) from the Everglades to Florida Bay. Rapid changes in nutrient availability and vegetation distribution during the last 50 years show that future ecosystem restoration actions and land use decisions can exert a major influence, similar to sea level rise over the short term, on nutrient cycling and wetland productivity in the EMER.

Over the past 14 years, long-term ecological research (LTER) was conducted on the desert perennial, Welwitschia mirabilis (Gnetales: Welwitschiaceae), located in the Welwitschia Wash near Gobabeb in the Central Namib Desert. We measured... more

Over the past 14 years, long-term ecological research (LTER) was conducted on the desert perennial, Welwitschia mirabilis (Gnetales: Welwitschiaceae), located in the Welwitschia Wash near Gobabeb in the Central Namib Desert. We measured leaf growth of 21 plants on a monthly basis and compared this with climatic data. The population structure as well as its spatial distribution was determined for 110 individuals. Growth rate was 0.37 mm day−1, but varied 22-fold within individuals, fluctuating seasonally and varying between years. Seasonal patterns were correlated with air humidity, while annual differences were affected by rainfall. During three years, growth rate quadrupled following episodic rainfall events >11 mm during mid-summer. One natural recruitment event followed a 13-mm rainfall at the end of summer. Fog did not appear to influence growth patterns and germination. Plant location affected growth rate; plants growing on the low banks, or ledges, of the main drainage channel grew at a higher rate, responded better and longer to rainfall and had relatively larger leaves than plants in the main channel or its tributaries. This could be due to better water and nutrient conditions on the ledges than elsewhere. The population appears to be growing outwards, with the smallest (youngest?) plants highest. Sex ratio was male-biased and males grew larger than females. Our study, in conjunction with the extensive literature base on Welwitschia, published here in a bibliography comprising 297 papers, indicates the knowledge gaps and needs for further ecological studies, including the continuation of our LTER programme. This should elucidate the reproductive output, seed dispersal, recruitment, water availability, age structure, and ecological differences between the sexes, and long-term life history strategies. Such knowledge would contribute to desert ecology and improve the management strategies of this unique Namib Desert perennial.

Las dimensiones ecológicas, sociales, institucionales y políticas de los problemas ambientales abarcan escalas espaciales y temporales que exceden a la mayoría de las investigaciones científicas. Una alternativa que crece con el tiempo a... more

Las dimensiones ecológicas, sociales, institucionales y políticas de los problemas ambientales abarcan escalas espaciales y temporales que exceden a la mayoría de las investigaciones científicas. Una alternativa que crece con el tiempo a nivel mundial es la aproximación Long-Term Ecological Research (LTER) o Long-Term Socio-Ecological Research (LTSER), pero que presenta vacíos temáticos y geográficos. Uno de estos vacíos es la Argentina, sin embargo, existe una gran cantidad de experiencia para poder integrar potencialmente al país a dicha red. El objetivo de este trabajo es evaluar el marco general de la investigación ecológica a largo plazo que se realiza en Argentina, y particularmente en la Patagonia Austral, tomamos dos líneas de trabajo como estudios de caso: (i) la ecología y conservación de los bosques nativos a través del manejo forestal y silvopastoril sostenible, y (ii) la ecología y el manejo de las invasiones biológicas. Se presenta una reseña de las investigaciones realizadas (en el pasado y al presente), sus resultados, las estrategias aplicadas en el pasado y las lecciones aprendidas. Esta reseña permite inferir acerca de la factibilidad de implementar esta aproximación en la Argentina, y que el mismo pueda ser sostenidos en el tiempo y que sea integrados entre distintas disciplinas y tomadores de decisiones. Se concluye que existe un potencial actual y grandes oportunidades a futuro para poder consolidar una red del tipo LTER/LTSER en Argentina.

The amount of carbon stored in savannas represents a significant uncertainty in global carbon budgets, primarily because fire causes actual biomass to differ from potential biomass. We analyzed the structural response of woody plants to... more

The amount of carbon stored in savannas represents a significant uncertainty in global carbon budgets, primarily because fire causes actual biomass to differ from potential biomass. We analyzed the structural response of woody plants to long-term experimental burning in savannas. The experiment uses a randomized block design to examine fire exclusion and the season and frequency of burn in 192 7-ha experimental plots located in four different savanna ecosystems. Although previous studies would lead us to expect tree density to respond to the fire regime, our results, obtained from four different savanna ecosystems, suggest that the density of woody individuals was unresponsive to fire. The relative dominance of small trees was, however, highly responsive to fire regime. The observed shift in the structure of tree populations has potentially large impacts on the carbon balance. However, the response of tree biomass to fire of the different savannas studied were different, making it d...

Historically, interactions and trends between biodiversity, ecosystem function (EF) and land use practices in southern Patagonia (Argentina) have been largely undocumented and poorly understood. Since 2002, 1214 permanent and... more

Historically, interactions and trends between biodiversity, ecosystem function (EF) and land use practices in southern Patagonia (Argentina) have been largely undocumented and poorly understood. Since 2002, 1214 permanent and semi-permanent plots within the PEBANPA Network have enabled researchers to monitor and assess functions and trends among vegetation parameters, biodiversity, forest dynamics, soil physicochemical characteristics, and land use management. The objectives of this manuscript are to communicate the role and rationale of the PEBANPA Network, summarize examples of the main results found within the network and provide guidance to decision makers with respect to advancing sustainable land management in southern Patagonia. As examples, rangeland health indices, seedling and sapling regener-ation under different timber managed forests, litterfall and seeds production under silvopastoral use, and soil carbon content impacted by livestock grazing have all been assessed. Vegetation and environmental variables including soil respiration, soil water infiltration, soil water retention capacity, soil erosion, and litter cover were measured under different grazing intensities. Livestock and forestry production have caused changes in the original floristic patterns, with several areas experiencing desertification. Heavy stocking rates have caused the greatest impacts on grassland soil carbon (C) loss as a consequence of soil erosion. We were able to conclude that low − medium grazing intensities yield the most positive impacts for biodiversity and soil physicochemical characteristics. Studies regarding levels of seedling and sapling regeneration post-harvest of timber further supported the importance of long-term monitoring due to the strongest evidence of interactions occurring 20 to 30 years after harvest. Distribution patterns of vascular plants and epigaeic coleopterons diversity revealed statistically significant differences among geographical zones and dominant vegetation types. The PEBANPA Network helps southern Patagonia address the challenges of unsustainable land management and climate change through monitoring ecosystem function and services. Long-term monitoring of biodiversity and ecosystem function help decision makers better understand the impacts of land use practices, develop well-informed policies and secure present and future human well-being.

The Program for Biodiversity Research (PPBio) is an innovative program designed to integrate all biodiversity research stakeholders. Operating since 2004, it has installed long-term ecological research sites throughout Brazil and its... more

The Program for Biodiversity Research (PPBio) is an innovative program designed to integrate all biodiversity research stakeholders. Operating since 2004, it has installed long-term ecological research sites throughout Brazil and its logic has been applied in some other southern-hemisphere countries. The program supports all aspects of research necessary to understand biodiversity and the processes that affect it. There are presently 161 sampling sites (see some of them at Supplementary Appendix), most of which use a standardized methodology that allows comparisons across biomes and through time. To date, there are about 1200 publications associated with PPBio that cover topics ranging from natural history to genetics and species distributions. Most of the field data and metadata are available through PPBio web sites or DataONE. Metadata is available for researchers that intend to explore the different faces of Brazilian biodiversity spatio-temporal variation, as well as for managers intending to improve conservation strategies. The Program also fostered, directly and indirectly, local technical capacity building, and supported the training of hundreds of undergraduate and graduate students. The main challenge is maintaining the long-term funding necessary to understand biodiversity patterns and processes under pressure from global environmental changes.

A site description directory plays a central role as a catalog for a network of research sites. Such a directory represents a keystone element in an information management system. A directory contributes to community communications both... more

A site description directory plays a central role as a catalog for a network of research sites. Such a directory represents a keystone element in an information management system. A directory contributes to community communications both through documentation of member information and relationships as well as through design feedback elicited from participants in the ongoing process of developing the catalog system. Presentation of a description directory for networked research sites via web interfaces permits distributed, remote site data input and access. There is a dual challenge in creating an extensible directory design: first to capture relevant content and second to incorporate such a system within the work practice of the community represented to ensure its continued evolution. We present here a directory designed for the Long-Term Ecological Research (LTER) Network community

With an overarching goal of addressing global and regional sustainability challenges, Long Term Socio-Ecological Research Platforms (LTSER) aim to conduct place-based research, to collect and synthesize both environmental and... more

With an overarching goal of addressing global and regional sustainability challenges, Long Term Socio-Ecological Research Platforms (LTSER) aim to conduct place-based research, to collect and synthesize both environmental and socio-economic data, and to involve a broader stakeholder pool to set the research agenda. To date there have been few studies examining the output from LTSER platforms. In this study we enquire if the socio-ecological research from 25 self-selected LTSER platforms of the International Long-Term Ecological Research (ILTER) network has produced research products which fulfil the aims and ambitions of the paradigm shift from ecological to socio-ecological research envisaged at the turn of the century. In total we assessed 4983 publically available publications, of which 1112 were deemed relevant to the socio-ecological objectives of the platform. A series of 22 questions were scored for each publication, assessing relevance of responses in terms of the disciplina...

Background: Many minerotrophic fens in Central Europe have undergone similar sequences of land-use transformation. Drained and used as meadows or pastures for decades in the twentieth century, they were abandoned in the 1990s due to... more

Background: Many minerotrophic fens in Central Europe have undergone similar sequences of land-use transformation. Drained and used as meadows or pastures for decades in the twentieth century, they were abandoned in the 1990s due to changes in agricultural economics. This sequence of land-use change has a severe impact on vegetation and is likely to initiate secondary succession and is possibly leading to an impoverishment in species diversity and to taxonomic homogenisation.
Aims: We assess the impact of agricultural use and subsequent abandonment on vegetation composition in a percolation fen in north Germany and characterise successional changes and changes in abiotic site conditions.
Methods: In 2010, we resampled 77 plots of a phytosociological survey from 1967–1970 in a lowland percolation mire complex in the lower Recknitz valley, north-east Germany. These included three characteristic vegetation types of percolation fens. To investigate and quantify vegetation changes we used dissimilarity measures, diversity metrics and ecological species indicator values.
Results: Overall species richness declined only slightly while there was a more pronounced decrease in species richness at the plot level in all recorded vegetation types, resulting in increased beta diversity. Generalist and nitrophilous species increased in abundance, indicating ongoing succession.
Conclusions: Drainage for agricultural use and subsequent abandonment has long-lasting effects. Altered hydrological and nutrient status of the fen soil has initiated secondary succession. There is indication of an extinction debt that in the future may lead to an impoverishment of species diversity in the area. Conservation of open mesotrophic fen species may thus only be achieved if moderate use is continued and hydrologic conservation measures are applied on wide contiguous areas.

Temperate and semi-arid regions of Argentina are undergoing rapid habitat conversion as a result of several human activities (i.e. grazing, logging, agriculture, etc.). These arid ecosystems contain many endemic species and have played an... more

Temperate and semi-arid regions of Argentina are undergoing rapid habitat conversion as a result of several human activities (i.e. grazing, logging, agriculture, etc.). These arid ecosystems contain many endemic species and have played an important role in the evolution of South American biota. The Man and Biosphere Reserve of Ñacuñán (12,800 ha) is located in the central region of the lowland Monte Desert. The reserve is a stand within a highly disturbed matrix characterized by deforestation (i.e. mesquite,Prosopis)and overgrazing. Major vegetational and animal communities recovered after the reserve was fenced in 1972, and Ñacuñán thus provides critical data describing the recovery of biotic and abiotic components of the Monte Desert when anthropogenic assaults are minimized. Indeed, the Reserve of Ñacuñán protects many distinctive habitats of the Monte Desert, including mesquite forest, or algarrobal, and several representative animals of the South American biota (i.e. tinamous, rhea, marsupials, edentates and caviomorph rodents). Several research projects on community ecology, herbivory, disturbances, ecology and ecophysiology have been or are being developed in the reserve. Although the town of Ñacuñán lies within the reserve, the link between the research community and the local people has not been strong, persistent or effective. The reserve is the most important site in Argentina for monitoring the ecological health of the Monte Desert and for developing indicators of desertification. Its potential is great for long-term ecological research and for strengthening the infrastructure of science. Sustainable development in the next millennium requires integrating the activities of the research, local people, ranch landowners and governmental sectors so as to infuse science-based proposals into management and conservation initiatives.

The spatial and temporal distribution of groundwater recharge depends on the complex interaction of hydrologic, atmospheric, pedologic, vegetative, and geologic processes, making it one of the most difficult and uncertain hydrologic... more

The spatial and temporal distribution of groundwater recharge depends on the complex interaction of hydrologic, atmospheric, pedologic, vegetative, and geologic processes, making it one of the most difficult and uncertain hydrologic parameters to quantify, yet understanding its distribution is a basic prerequisite for effective groundwater resource management and modeling. We use a modular terrestrial biosphere model (IBIS) (Kucharik et al., 2000), which couples carbon, nitrogen, water, and energy fluxes, to examine the spatial and temporal distribution and variability of groundwater recharge across a 400 km2 forested watershed in northern Wisconsin. The model uses a two-layer vegetation (upper and lower canopy) and six-layer soil scheme to simulate the exchange of energy and water between the soil surface, vegetation canopies, and the atmosphere. Inputs to the model include vegetation land cover type, soil variables (soil type and hydrologic characteristics), and meteorological par...