Land Users – Land Watchers

GróLind is a collaborative project with the aim of monitoring Icelandic vegetation and soil resources. It was founded in 2017 by the Icelandic National Associations of Sheep Farmers, the Farmers Association of Iceland, Ministry of Industries and Innovation, and the Soil Conservation Service of Iceland. GróLind is a collaborative project and cooperation with stakeholders, such as the science community, landowners, and others, is a fundamental concept in the project. In this project, the state of vegetation and soils are evaluated. Currently, a citizen science project is being developed within GróLind, in which land-users will annually monitor, using a mobile app, the conditions of the land they utilize. The monitoring will be based up on permanent photo-points and simple ecological measurements. These data will be used together with more detailed measurements done by specialists, to assess the state and changes in Iceland\u27s vegetation and soil resources. Land users\u27 participation provides more extensive and accurate monitoring, both spatially and temporally. Cooperation between scientists and land users increases the flow of knowledge and trust between groups, ensuring that the knowledge gained in the project will be used for sustainable land management. Furthermore, the data will be used to develop research-based indicators for sustainable land-use that later can simplify the monitoring

State and Transition Models in Space and Time – Using STMs to Understand Broad Patterns of Ecosystem Change in Iceland

Managing ecological systems sustainably requires a deep understanding of ecosystem structure and the processes driving their dynamics. Conceptual models can lead to improved management, by providing a framework for organizing knowledge about a system and identifying the causal agents of change. We developed state-and-transition models (STMs) to describe landscape changes in Iceland over three historical periods with different human influence, from pre-settlement to present days. Our models identified the set of possible states, transitions and thresholds in these ecosystems and their changes over time. To illustrate the use of these models for predicting and improving management interventions, we applied our present-day STM to a case study in the central highlands of Iceland and monitored ecosystem changes within an ongoing field experiment with two management interventions (grazing exclusion and fertilization) in areas experiencing contrasting stages of degradation. The results of the experiment broadly align with the predictions of the model and underscore the importance of conceptual frameworks for adaptive management, where the best available knowledge is used to continuously refine and update the models

Characterization of Atlantic Cod Spawning Habitat and Behavior in Icelandic Coastal Waters

The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15-16 April 2009). We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON), as well as a remotely operated underwater vehicle (ROV). A total of five fish species were identified through ROV surveys: including cusk Brosme brosme, Atlantic cod, haddock Melanogrammus aeglefinus, lemon sole Microstomus kitt, and Atlantic redfish Sebastes spp. Of the three habitats identified in the acoustic surveys, the transitional habitat between boulder/lava field and sand habitats was characterized by greater fish density and acoustic target strength compared to that of sand or boulder/lava field habitats independently. Atlantic cod were observed behaving in a manner consistent with published descriptions of spawning. Individuals were observed ascending 1-5 m into the water column from the bottom at an average vertical swimming speed of 0.20-0.25 m s21 and maintained an average spacing of 1.0-1.4 m between individuals. Our results suggest that cod do not choose spawning locations indiscriminately despite the fact that it is a broadcast spawning fish with planktonic eggs that are released well above the seafloor

Buffering effects of soil seed banks on plant community composition in response to land use and climate

Aim Climate and land use are key determinants of biodiversity, with past and ongoing changes posing serious threats to global ecosystems. Unlike most other organism groups, plant species can possess dormant life‐history stages such as soil seed banks, which may help plant communities to resist or at least postpone the detrimental impact of global changes. This study investigates the potential for soil seed banks to achieve this. Location Europe. Time period 1978–2014. Major taxa studied Flowering plants. Methods Using a space‐for‐time/warming approach, we study plant species richness and composition in the herb layer and the soil seed bank in 2,796 community plots from 54 datasets in managed grasslands, forests and intermediate, successional habitats across a climate gradient. Results Soil seed banks held more species than the herb layer, being compositionally similar across habitats. Species richness was lower in forests and successional habitats compared to grasslands, with annual temperature range more important than mean annual temperature for determining richness. Climate and land‐use effects were generally less pronounced when plant community richness included seed bank species richness, while there was no clear effect of land use and climate on compositional similarity between the seed bank and the herb layer. Main conclusions High seed bank diversity and compositional similarity between the herb layer and seed bank plant communities may provide a potentially important functional buffer against the impact of ongoing environmental changes on plant communities. This capacity could, however, be threatened by climate warming. Dormant life‐history stages can therefore be important sources of diversity in changing environments, potentially underpinning already observed time‐lags in plant community responses to global change. However, as soil seed banks themselves appear, albeit less, vulnerable to the same changes, their potential to buffer change can only be temporary, and major community shifts may still be expected

Evidence of Segregated Spawning in a Single Marine Fish Stock: Sympatric Divergence of Ecotypes in Icelandic Cod?

There is increasing recognition of intraspecific diversity and population structure within marine fish species, yet there is little direct evidence of the isolating mechanisms that maintain it or documentation of its ecological extent. We analyzed depth and temperature histories collected by electronic data storage tags retrieved from 104 Atlantic cod at liberty ≥1 year to evaluate a possible isolating mechanisms maintaining population structure within the Icelandic cod stock. This stock consists of two distinct behavioral types, resident coastal cod and migratory frontal cod, each occurring within two geographically distinct populations. Despite being captured together on the same spawning grounds, we show the behavioral types seem reproductively isolated by fine-scale differences in spawning habitat selection, primarily depth. Additionally, the different groups occupied distinct seasonal thermal and bathymetric niches that generally demonstrated low levels of overlap throughout the year. Our results indicate that isolating mechanisms, such as differential habitat selection during spawning, might contribute to maintaining diversity and fine-scale population structure in broadcast-spawning marine fishes

More warm‐adapted species in soil seed banks than in herb layer plant communities across Europe

Responses to climate change have often been found to lag behind the rate of warming that has occurred. In addition to dispersal limitation potentially restricting spread at leading range margins, the persistence of species in new and unsuitable conditions is thought to be responsible for apparent time-lags. Soil seed banks can allow plant communities to temporarily buffer unsuitable environmental conditions, but their potential to slow responses to long-term climate change is largely unknown. As local forest cover can also buffer the effects of a warming climate, it is important to understand how seed banks might interact with land cover to mediate community responses to climate change. We first related species-level seed bank persistence and distribution-derived climatic niches for 840 plant species. We then used a database of plant community data from grasslands, forests and intermediate successional habitats from across Europe to investigate relationships between seed banks and their corresponding herb layers in 2763 plots in the context of climate and land cover. We found that species from warmer climates and with broader distributions are more likely to have a higher seed bank persistence, resulting in seed banks that are composed of species with warmer and broader climatic distributions than their corresponding herb layers. This was consistent across our climatic extent, with larger differences (seed banks from even warmer climates relative to vegetation) found in grasslands. Synthesis. Seed banks have been shown to buffer plant communities through periods of environmental variability, and in a period of climate change might be expected to contain species reflecting past, cooler conditions. Here, we show that persistent seed banks often contain species with relatively warm climatic niches and those with wide climatic ranges. Although these patterns may not be primarily driven by species' climatic adaptations, the prominence of such species in seed banks might still facilitate climate-driven community shifts. Additionally, seed banks may be related to ongoing trends regarding the spread of widespread generalist species into natural habitats, while cool-associated species may be at risk from both short- and long-term climatic variability and change

Original capture locations of Atlantic cod implanted with data storage tags (DSTs) around Iceland.

<p>Insets show the sampling regions in north (N1) and south (S1-S5) Iceland and indicate the number of recovered coastal (C, ○) and frontal (F, <b>▵</b>) individuals originally tagged and released in that area. The bracketed numbers and filled symbols represent individuals for whom spawning information could be extracted from their DST profile. Scale bar within each inset indicates a distance of 10 km.</p

Temperature and depth profiles collected by electronic data storage tags implanted in Atlantic cod.

<p>Examples of one year depth and temperature profiles of frontal (A) and coastal (B) behavioral types of Atlantic cod in Iceland showing in-migration to spawning habitat, time spent at spawning grounds, and out-migration back to feeding grounds in the highlighted areas. Temperature is represented by a red line while depth is represented by a blue one. Periods interpreted as time spent in spawning aggregations was characterized by the highlighted portions with a clear tidal signature between in-migration and out-migration (C). Arrows indicate events interpreted as possible Atlantic cod spawning events as described by Brawn (1961a, b), Rose (1993), and Hutchings et al. (1999).</p

Definition of coastal and frontal behavioral types of Atlantic cod.

<p>Mean (± SE) proportion of daily depth (A) and temperature (B) ranges experienced by individuals tagged with electronic data storage tags (DSTs). Discriminant function analysis (C) performed on the proportion of daily depth and temperature ranges experienced by each individual indicated a clear separation between the coastal (northern: ○; southern: •) and frontal (northern: <b>▵</b>; southern: ▴) behavioral types based upon the proportion of depth and temperature ranges. The visual and DFA classifications of the five individuals represented by a gray circle or triangle could not be reconciled and these individuals were excluded from further analysis. Arrows indicate individuals whose depth and temperature profiles are displayed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017528#pone-0017528-g002" target="_blank">Fig. 2a</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017528#pone-0017528-g002" target="_blank">2b</a>.</p