Terrestrial Habitat Types Research Articles

Improved description of terrestrial habitat types by including microbial communities as indicators

Soils host diverse communities of microorganisms essential for ecosystem functions and soil health. Despite their importance, microorganisms are not covered by legislation protecting biodiversity or habitats, such as the Habitats Directive. Advances in molecular methods have caused breakthroughs in microbial community analysis, and recent studies have shown that parts of the communities are habitat-specific. If distinct microbial communities are present in the habitat types defined in the Habitats Directive, the Directive may be improved by including these communities. Thus, monitoring and reporting of biodiversity and conservation status of habitat types could be based not only on plant communities but also on microbial communities. In the present study, bacterial and plant communities were examined in six habitat types defined in the Habitats Directive by conducting botanical surveys and collecting soil samples for amplicon sequencing across 19 sites in Denmark. Furthermore, selected physico-chemical properties expected to differ between habitat types and explain variations in community composition of bacteria and vegetation were analysed (pH, electrical conductivity (EC), soil texture, soil water repellency, soil organic carbon content (OC), inorganic nitrogen, and in-situ water content (SWC)). Despite some variations within the same habitat type and overlaps between habitat types, habitat-specific communities were observed for both bacterial and plant communities, but no correlation was observed between the alpha diversity of vegetation and bacteria. PERMANOVA analysis was used to evaluate the variables best able to explain variation in the community composition of vegetation and bacteria. Habitat type alone could explain 46% and 47% of the variation in bacterial and plant communities, respectively. Excluding habitat type as a variable, the best model (pH, SWC, OC, fine silt, and Shannon's diversity index for vegetation) could explain 37% of the variation for bacteria. For vegetation, the best model (pH, EC, ammonium content and Shannon's diversity index for bacteria) could explain 25% of the variation. Based on these results, bacterial communities could be included in the Habitats Directive to improve the monitoring, as microorganisms are more sensitive to changes in the environment compared to vegetation, which the current monitoring is based on.

Living on the edge: Predicting invertebrate richness and rarity in disturbance‐prone aquatic–terrestrial ecosystems

Abstract Temporal fluctuations in cause the spatial extent of wet and dry habitats to vary in aquatic–terrestrial riverine ecosystems, complicating their biomonitoring. As such, biomonitoring efforts may fail to characterize the species that inhabit such habitats, hampering assessments of their biodiversity and implementation of evidence‐informed management strategies. Relationships between the dynamic characteristics of aquatic–terrestrial habitats and their communities are well known. Thus, habitat characteristics may enable estimation of faunal assemblage characteristics such as taxonomic richness, regardless of in‐channel water levels. We investigated whether indicators summarizing habitat survey data can predict two metrics representing terrestrial invertebrate assemblages (e.g. taxa richness) in two aquatic–terrestrial habitats: exposed riverine sediments and dry temporary streams. We also compared the performance of unimetric and multimetric habitat indicators in making predictions. In exposed riverine sediments, >88% of predictions were correlated with observed taxa richness and an index of conservation status. Values predicted by exposed riverine sediment samples were correlated with those observed in temporary stream channels with comparable riparian (i.e. largely agricultural) land use, but not those observed in channels with contrasting (i.e. more urban) land use. Unimetric habitat indicators performed similarly to more complex multimetric indicators, with each explaining ≤6% of the variability in taxa richness and the index of conservation status. The different spatial scales at which invertebrates respond to habitat conditions and at which indicators record habitat conditions, and a more comprehensive training dataset that incorporates a full range of habitat conditions (i.e. land use), may improve future predictions. We demonstrate that invertebrate assemblage characteristics can be predicted regardless of in‐channel water levels. Agreement between exposed riverine sediment predictions and temporary stream observations suggests that these predictions are transferable among a range of aquatic–terrestrial habitat types, and could thus be widely applied to aid conservation of riverine biodiversity in dynamic aquatic–terrestrial ecosystems.

A sampling strategy for assessing habitat coverage at a broad spatial scale

• We develop an adaptive monitoring approach, to estimate the coverage of habitat types using a two-phase sampling scheme. • The adaptive monitoring approach demonstrated high reliability in a simulation study performed on the whole country of Italy. • The method is cost effective, adaptable across habitat types, and transferable to other countries or whole European Union. The quantitative assessment of habitat conservation status is a major task for European Union member states in compliance with Council Directive 92/43. One goal of the European 2030 Biodiversity Strategy is the effective management of habitats that show declining trends. While various approaches have been adopted for national assessments, there is no consensus on how to achieve common statistically sound estimates of the criteria indicated by the EU Directive for the evaluation of the status and trend of habitat types. Here, we present an adaptive monitoring approach based on a two-phase sampling scheme to estimate the coverage of EU terrestrial habitat types, which is one of the four criteria indicated by the Habitats Directive. We used 9 habitats distributed among different EU member states choosing Italy as a case study. The development of the methodological approach is described, and a simulation study was performed to check the precision of the coverage estimators accounting for the lack of sampled data (nonresponse treatment), subregions and sustainable sampling effort. We found that our two-phase sampling approach has the potential to increase precision in estimating the coverage of habitat types (approximated at 1 ha cell size) with respect to the precision achieved by simple random sampling without replacement, which is the simplest sampling approach. Adopting a small sampling fraction ( ⩽ 0.04 % ) of the survey area, the relative standard errors ranged from 7 to 15 % for common habitats whose presence is strongly correlated with the habitat suitability scores furnished by an expert team. In the challenging context of a “mandated” monitoring type, our approach provides sound statistical estimates of habitat coverage with the possibility of applying a standardised and transferable sampling scheme that is easily repeatable over time.

Diversity of European habitat types is correlated with geography more than climate and human pressure.

Habitat richness, that is, the diversity of ecosystem types, is a complex, spatially explicit aspect of biodiversity, which is affected by bioclimatic, geographic, and anthropogenic variables. The distribution of habitat types is a key component for understanding broad‐scale biodiversity and for developing conservation strategies. We used data on the distribution of European Union (EU) habitats to answer the following questions: (i) how do bioclimatic, geographic, and anthropogenic variables affect habitat richness? (ii) Which of those factors is the most important? (iii) How do interactions among these variables influence habitat richness and which combinations produce the strongest interactions? The distribution maps of 222 terrestrial habitat types as defined by the Natura 2000 network were used to calculate habitat richness for the 10 km × 10 km EU grid map. We then investigated how environmental variables affect habitat richness, using generalized linear models, generalized additive models, and boosted regression trees. The main factors associated with habitat richness were geographic variables, with negative relationships observed for both latitude and longitude, and a positive relationship for terrain ruggedness. Bioclimatic variables played a secondary role, with habitat richness increasing slightly with annual mean temperature and overall annual precipitation. We also found an interaction between anthropogenic variables, with the combination of increased landscape fragmentation and increased population density strongly decreasing habitat richness. This is the first attempt to disentangle spatial patterns of habitat richness at the continental scale, as a key tool for protecting biodiversity. The number of European habitats is related to geography more than climate and human pressure, reflecting a major component of biogeographical patterns similar to the drivers observed at the species level. The interaction between anthropogenic variables highlights the need for coordinated, continental‐scale management plans for biodiversity conservation.

Spatial Variability Aware Deep Neural Networks (SVANN): A General Approach

Spatial variability is a prominent feature of various geographic phenomena such as climatic zones, USDA plant hardiness zones, and terrestrial habitat types (e.g., forest, grasslands, wetlands, and deserts). However, current deep learning methods follow a spatial-one-size-fits-all (OSFA) approach to train single deep neural network models that do not account for spatial variability. Quantification of spatial variability can be challenging due to the influence of many geophysical factors. In preliminary work, we proposed a spatial variability aware neural network (SVANN-I, formerly calledSVANN) approach where weights are a function of location but the neural network architecture is location independent. In this work, we explore a more flexible SVANN-E approach where neural network architecture varies across geographic locations. In addition, we provide a taxonomy of SVANN types and a physics inspired interpretation model. Experiments with aerial imagery based wetland mapping show that SVANN-I outperforms OSFA and SVANN-E performs the best of all.

Herpetological Assemblages in Tropical Forests of the Taguibo Watershed, Butuan City, Eastern Mindanao, Philippines

Tropical watershed ecosystems support heterogeneous habitats and diverse non-human species assemblages, together providing ecosystem services to humans. Amphibians and reptiles are recognized as sensitive indicators of ecosystem “health,” related to beneficial services (provisional, regulating, cultural, structural, functional) human societies receive from terrestrial watersheds. The Taguibo Watershed supplies fresh drinking water to Butuan City in the Caraga Region of northeast Mindanao Island. However, very little is known about the herpetofauna of the area. Here, we synthesize biodiversity data from historical (1971, 1979) and recent (2013, 2017) herpetological surveys from the region. We utilize specimen-associated occurrence records and natural history information to produce a species inventory, analyze their habitat utilization, and characterize diversity metrics to describe herpetological communities of the watershed – resulting in 44 species (27 new records). A number of historically-documented species persist, having partitioned riparian and terrestrial habitat types in dipterocarp and secondary-growth forests of Taguibo. Reptiles exhibit little overlap in the use of microhabitats – in contrast to amphibians, which exhibit either unique or frequently shared microhabitat substrates. In terrestrial microhabitats (not immediately associated with water), many newly-recorded reptiles and amphibians (particularly, of the genus Platymantis) partition space predictably – either occupying a single microhabitat or, in one species (a pit viper, Tropidolaemus subannulatus), two microhabitats. We anticipate that our initial characterization of Taguibo’s herpetofauna may serve as a baseline to promote further research and facilitate conservation initiatives. We emphasize the importance of primary sources – field-based surveys and re-surveys – and open-access biodiversity data served via online platforms that provide live, transparent access to original, unaltered data. Anthropogenic threats involving economic-driven activities present a need for field-based research in support of watershed management. Periodic, survey, and re-survey studies – continuously updating earlier work – are the most reliable, repeatable, and publicly-transparent use of biodiversity survey data in support of societal benefits and ecosystem services.

A global map of terrestrial habitat types

We provide a global, spatially explicit characterization of 47 terrestrial habitat types, as defined in the International Union for Conservation of Nature (IUCN) habitat classification scheme, which is widely used in ecological analyses, including for quantifying species’ Area of Habitat. We produced this novel habitat map for the year 2015 by creating a global decision tree that intersects the best currently available global data on land cover, climate and land use. We independently validated the map using occurrence data for 828 species of vertebrates (35152 point plus 8181 polygonal occurrences) and 6026 sampling sites. Across datasets and mapped classes we found on average a balanced accuracy of 0.77 (bar{+}0.14 SD) at Level 1 and 0.71 (bar{+}0.15 SD) at Level 2, while noting potential issues of using occurrence records for validation. The maps broaden our understanding of habitats globally, assist in constructing area of habitat refinements and are relevant for broad-scale ecological studies and future IUCN Red List assessments. Periodic updates are planned as better or more recent data becomes available.

Multi‐taxon inventory reveals highly consistent biodiversity responses to ecospace variation

Amidst the global biodiversity crisis, identifying general principles for variation of biodiversity remains a key challenge. Scientific consensus is limited to a few macroecological rules, such as species richness increasing with area, which provide limited guidance for conservation. In fact, few agreed ecological principles apply at the scale of sites or reserve management, partly because most community‐level studies are restricted to single habitat types and species groups. We used the recently proposed ecospace framework and a comprehensive data set for aggregating environmental variation to predict multi‐taxon diversity. We studied richness of plants, fungi and arthropods in 130 sites representing the major terrestrial habitat types in Denmark. We found the abiotic environment (ecospace position) to be pivotal for the richness of primary producers (vascular plants, mosses and lichens) and, more surprisingly, little support for ecospace continuity as a driver. A peak in richness at intermediate productivity adds new empirical evidence to a long‐standing debate over biodiversity responses to productivity. Finally, we discovered a dominant and positive response of fungi and insect richness to organic matter accumulation and diversification (ecospace expansion). Two simple models of producer and consumer richness accounted for 77% of the variation in multi‐taxon species richness suggesting a significant potential for generalization beyond individual species responses. Our study widens the traditional conservation focus on vegetation and vertebrate populations unravelling the importance of diversification of carbon resources for diverse heterotrophs, such as fungi and insects.

The impacts of oil palm plantation establishment on the habitat type, species diversity, and feeding guild of mammals and herpetofauna

Kwatrina RT, Santosa Y, Bismark M, Santoso N. 2018. The impacts of oil palm plantation establishment on the habitat type, species diversity, and feeding guild of mammals and herpetofauna. Biodiversitas 19: 1213-1219. Indonesia is the world’s largest producer of palm oil. Contributing 2.14% to the country’s gross domestic product, palm oil plays an important role in the national economy from plantation sector. However, the expansion of oil palm plantations has brought negative impacts to forests and wildlife. Little is known to what extent these negative impacts on mammals and reptiles can be reduced through better management. To address this knowledge gap, the current study assessed species diversity as affected by the establishment of the oil palm plantation in Central Kalimantan, a tropical biodiversity hotspot in Asia. We conducted 25 line transect surveys and visual encounter surveys in oil palm areas, shrubs and secondary forests in these landscapes. The results indicated that the establishment of oil palm plantation negatively impacted species abundance and diversity, and changed the mammal and reptile species composition, by favoring ecologically generalist species. For forest specialist species, forested areas like HCV and HCS, play an important role in maintaining habitat heterogeneity in oil palm landscapes. Mammal species found in habitat conditions following oil palm plantations belong to some feeding groups, whereas all species of herpetofauna have terrestrial habitat types. These mammal and herpetofauna species can live and function in the food chain in the oil palm plantation ecosystem.

Lidar-derived variables as a proxy for fungal species richness and composition in temperate Northern Europe

Biodiversity is declining on a global scale and the limited resources available for conservation efforts and research need to be used efficiently. Fungi are a megadiverse taxonomic group where lack of knowledge impedes sufficient conservation focus. Inventories of fungi require a high level of expertise and are difficult and expensive due to seasonal variation and fluctuation in sporocarp formation. Lidar offers objective, fine-resolution and potentially cheap and broad scale data for representing vegetation structure and has proven useful for prediction of the diversity of plant and animal species. In this study, we used lidar-derived variables as explanatory variables in models of fungal species richness and controlling gradients of species composition, represented by three ordination axes derived from multidimensional scaling. The fungal data comprised a data set of 1527 species recorded in three inventories of 121 sites covering all major terrestrial habitat types across Denmark. We compared the performance of lidar-derived explanatory variables with two field inventory-based sets of variables: 1) lists of vascular plants and 2) recordings of soil, microclimate and vegetation structure. Lidar-derived variables performed best in predicting fungal richness and the first ordination axis, interpreted as a gradient from low and open herb-dominated communities over closed swards and scrubs to closed-canopy forests (cross validated r2 of 0.50 and 0.81, respectively). The number of red-listed species and the second ordination axis were poorly predicted by lidar, and the third ordination axis was equally well detected by the three explanatory sets of variables (cross validated r2 of 0.38). From a fungal conservation perspective, it is promising that lidar-based variables hold information suitable for detecting major gradients in fungal richness and composition.

Habitat suitability assessment of constructed wetlands for the smooth newt (Lissotriton vulgaris [Linnaeus, 1758]): A comparison with natural wetlands

Given the current decline of natural wetlands worldwide and the consequent negative impacts on amphibians, wetlands constructed for the treatment of wastewaters have the potential to play a role in the protection of these animals. However, there is a paucity of information regarding the value of constructed wetlands (CWs) to amphibians, particularly relating to the terrestrial phase of their life-cycle. This study compares the terrestrial habitats of natural wetlands (NWs) and CWs as refuges for the smooth newt (Lissotriton vulgaris, [L., 1758]) with the aim of developing recommendations for CWs (both new and existing) to enhance their usefulness as newt-friendly habitats. Terrestrial habitats surrounding NWs and CWs were mapped using ArcGIS. Potential barriers to newt movement in addition to the presence of features such as wood or stone which could act as potential newt refuges were also mapped. Natural wetlands had significantly more terrestrial habitat types than CWs and while woodlands at both wetland types were most likely to contain features of benefit to newts, terrestrial habitats of NWs contained more features compared to those of CWs. The application of a Habitat Suitability Index, which assesses the likelihood of the presence of newts, resulted in seven of eight NWs compared to only two of eight CWs receiving “good” scores, the lower scores for CWs being due primarily to the presence of a barrier to newt movement. Recommendations for enhancing the design and management of CWs for smooth newts include less intensive ground maintenance, reduction of barriers to newt movement, judicious planting of suitable trees or shrubs and the provision of additional refuges such as wood or stone.

Phytosociological evaluation of terrestrial habitat types in Pyramiden area (Svalbard, Norway)

Natural habitats in the area of Pyramiden town (Svalbard, Norway) were assessed as a part of landscape planning for purposes of tourism development. Habitat types evalu-ation was done by using phytosociological units and assessed by IUCN categories. Altogether, 15 main habitat types were united in following groups: 1. Arctic tundra, 2. Barrens, screes, young alluvia areas and glaciers, 4. Wetlands and marshes, 5. Meadows and grasslands, 6. Anthropogenic open plant communities.

A landscape-level study on the breeding site characteristics of ten amphibian species in Central Europe

Temporary ponds are characterized as being in natural or close to natural states in Central and Eastern Europe, especially those located in forested landscapes. As these ponds function as breeding sites for many amphibians, they represent an ideal target to explore the terrestrial and aquatic habitat preferences of different species. We surveyed 133 small ponds in a forested, hilly region of North-Central Hungary. The occurrence of ten amphibian species and amphibian species richness were compared to six pond-related habitat variables and the extent of four terrestrial habitat types in the area surrounding the ponds. Our results suggest that most species’ occurrence and species richness are chiefly related to pond characteristics, although terrestrial habitat variables could also be a determining factor in particular species. Whereas the majority of amphibian species prefer larger, hence more permanent water bodies with abundant aquatic vegetation, the common frog (Rana temporaria) chooses small, shallow wallow pits for breeding and has special requirements concerning terrestrial habitat composition. This could explain its restricted distribution in the area. Our results suggest that maintaining a diverse set of ponds and forestry management which facilitates habitats’ structural heterogeneity are both important factors for the preservation of the rich amphibian fauna in Central Europe.

NATURDATA.DK – Danish monitoring program of vegetation and chemical plant and soil data from non-forested terrestrial habitat types

Vegetation and chemical plant and soil data from 18 terrestrial non-forested natural habitat types have been collected each year since 2004 (Table 1). Presently, cover data of plant species measured by pinpoint (16 grid points in 0.5 m x 0.5 m frame) and plant frequency data (5 m circles) exist for more than 50,000 plots; the measuring of chemical properties in plant, soil, and water samples has been less intense. Presently there are more than 12,000 registrations of carbon content and 57,000 measurements of pH in topsoil. Soils are always samples from the top 5 cm. On heathland habitats the thickness of the mor layer is measured. All data are georeferenced and can be accessed at http://www.naturdata.dk/ The data comprises approximately 1,200 sites both within and outside of Natura 2000 areas. At each site the measurements were made at 20-60 randomly positioned plots. 70% of the plots have been revisited each year, whereas 30 % have only been visited once. Each year a total number of additional 5,000 sample plots and registrations will be performed. The protocols for the different measurement types (in Danish) may be downloaded from http://www.dmu.dk/fileadmin/Attachments/TAN1_106_01_FDCNY1.pdf. This report describes the available content in the vegetation-plot database NATURDATA.DK (GIVD ID EU-DK-001).

Terrestrial Movements and Habitat Preferences of Male Cricket Frogs on a Golf Course

Northern Cricket Frogs, Acris crepitans, are experiencing population declines throughout their range for unknown reasons. Habitat alteration is one potential explanation, so evaluating habitat use and movement of Cricket Frogs could be valuable to protect and manage this species. To understand how altered landscapes influence Cricket Frog movements, we initiated a study at a golf course to assess the dispersal of adults on a variety of terrestrial habitat types (mown grass, unmown grass, or the ecotone between mown and unmown grass) released at different distances from a single pond (10, 20, or 40 m). We monitored movements of adult male frogs by marking individuals with fluorescent powder. Distance from the pond did not appear to affect movement or orientation toward the pond. However, Cricket Frog movement was significantly affected by habitat type. Cricket Frogs produced longer paths in unmown grass and were more likely to orient toward the pond than frogs released at the ecotone, which may be benefici...

Landscape transformation of an Alpine floodplain influenced by humans: historical analyses from aerial images

AbstractNatural floodplains are spatially heterogeneous and dynamic ecosystems but at the same time, a highly endangered landscape feature due to climate change and human impacts such as water storage, flood control and hydropower production. Flow is considered a master variable that shapes channel morphology and the heterogeneity, distribution, and turnover of floodplain habitats. Despite their highly dynamic nature, the relative abundance of different habitat elements (islands, gravel bars) in natural floodplains seems to remain relatively constant over ecological periods and is referred to as the shifting mosaic steady state concept. In this conceptual context, we analysed spatiotemporal changes in relative habitat abundance and channel complexity of an alpine floodplain from its near natural state in 1940 before water abstraction and levee construction until 2007 using historical aerial images. Within the first decades of impairment, the relative abundance of floodplain habitats that depend on flood and flow pulses such as parafluvial channels and islands shifted toward a greater abundance of terrestrial forest and grassland habitats. After 1986, the duration and frequencies of high‐precipitation events (>60 mm 24 h–1) triggering major, channel‐reworking floods increased substantially and caused a restructuring of the floodplain and decrease in the abundance of more terrestrial habitat types. These results are contrary to expectations of the shifting mosaic steady state concept yet suggest its potential application as an indicator of landscape transformation and human impacts on floodplain ecosystems. Last, the results raise the applied question as to whether an increased frequency of high flow events induced by climate change can contribute to floodplain restoration. Copyright © 2011 John Wiley & Sons, Ltd.

Stream characteristics and their implications for the protection of riparian fens and meadows

Summary 1. Running waters, including associated riparian areas, are embraced by international legal frameworks outlining targets for the preservation, protection and improvement of the quality of the environment. Interactions between stream and river processes and riparian habitats have not received much attention in the management of stream ecosystems, and integrated measures that consider both the ecological status of streams and rivers (sensu EU Water Framework Directive, WFD) and the conservation status of riparian habitats and species (sensu EU Habitats Directive, HD) are rare. 2. Here, we analysed the influence of stream size, morphology and chemical water characteristics for the distribution of water-dependent terrestrial habitat types, i.e. alkaline fens, periodically inundated meadows and meadows in riparian areas in Denmark using an extensive data set covering a total of 254 stream reaches. A species-based classification model was used to translate species lists into a standardised interpretation of habitat types protected by the HD in Denmark. 3. No size dependency was found regarding the distribution of fen and meadow vegetation. Instead, the distribution of fen and meadow vegetation was strongly affected by the morphology of the streams. Alkaline fens, periodically inundated meadows and meadows occurred six, five and four times, respectively, less frequently along channelised compared with natural stream reaches. Our results indicate that stream channelisation strongly interfered with the natural hydrology of riparian areas, affecting conditions needed to sustain protected fen and meadow communities. 4. We also found that water chemistry strongly influenced the occurrence of fen and meadow vegetation in riparian areas. The probability of finding fen and meadow vegetation was reduced when total phosphorus (TP) concentration exceeded 40–50 μg P L−1, whereas meadow vegetation responded less strongly to TP. 5. Our findings highlight the importance of restoring hydrology of riparian areas to improve conditions for fen and meadow vegetation, but also that the water chemistry should be considered when measures that increase hydrological connectivity result in an increase in the probability of flooding.

Investigating habitat-specific plant species pools under climate change

We used 474 European plant species to analyse the impacts of climate and land-use change on the composition of habitatspecific species pools in Germany. We quantified changes in the probability of occurrence of species in a grid cell using an ensemble of three statistical modelling techniques, namely generalized linear models (GLMs), generalized additive models (GAMs) and random forests (RFs), under three scenarios (average change +2.2, +2.9, and +3.8 ◦ C up to 2080). We evaluated the impact on single species occurrence and resulting species pools considering their affiliation to ten major terrestrial habitat types in both current (1961–90) and future projections (2051–80). Current habitat-specific species pools declined in size across all scenarios, e.g. by 24 ± 13% (mean ± s.d.) under the most severe scenario. We show that species responses may strongly vary among scenarios and different habitats with a minimum average projected range loss of 14% (±18%; species typical to urban habitats under moderate climate change assumptions, average temperature increase +2.2 ◦ C) to a maximum average projected range loss of 56% (±29%; species assemblages from mountain communities below the alpine zone at +3.8 ◦ C). A separate analysis of species composition in habitat-specific species pools revealed a significant interaction between the scenario and the major habitat classes. We found a higher risk for habitat types with high conservation value characterised by a significant association between number of nationally endangered species and projected range loss in major habitats. Thus, habitat-specific management and application of measures favouring dispersal are required for mitigation of climate change impacts.

Restoration Program Assessment of the National Estuarine Research Reserve System

We conducted a programmatic assessment of ecological restoration within the United States National Oceanic and Atmospheric Administration’s National Estuarine Research Reserve System (NERRS). The NERRS encompasses a network of 26 protected areas in 20 coastal states and Puerto Rico, representing a broad diversity of aquatic and terrestrial habitat types among pristine and disturbed settings. Nearly all of the reserves provide opportunities for habitat restoration and enhancement, and for research in restoration ecology. While the political, scientific, and management issues affecting restoration among the reserves vary, general restoration priorities are similar. The reserves provide a fertile arena for the development and standardization of restoration monitoring protocols and for the development of innovative restoration technologies and applications.

Effects of breeding pond isolation on the spatial and temporal dynamics of pond use by the tungara frog,Physalaemus pustulosus

1.Recent theoretical and empirical research has shown that habitat isolation can have strong effects on patterns of abundance and population dynamics of animals. Effects of habitat patch isolation may be particularly strong in taxa such as amphibians, which may have limited dispersal abilities and yet rely on breeding habitats that are variable in space and time.2.We manipulated the distribution of replicated artificial ponds in order to determine the effects of breeding pond isolation on the spatial and temporal dynamics of pond use by the tungara frog (Physalaemus pustulosusLynch), on Barro Colorado Island (BCI), Panama. Our principal objectives were to determine whether pond isolation affects if, when, and how much a pond will be used, and to determine the spatial scale over which isolation effects are likely to be important.3.We used three sets of experimental ponds: ponds placed at distances from 1 to 200 m from active natural breeding sites; ponds placed at these same distances from recently abandoned breeding sites; and ponds placed among different terrestrial habitat types and at least 200 m from any known breeding sites (‘sampling ponds’).4.We found that time to pond use increased with pond isolation, and that ponds near active sites were used more quickly than ponds near abandoned sites. The number of egg masses per pond decreased with pond isolation and was significantly lower near abandoned sites. Ponds near active breeding sites were more likely to be used by tungara frogs than both ponds near abandoned sites and sampling ponds.5.Used sampling ponds were clumped at spatial scales less than 200 m, and mark–recapture data suggest that tungara frogs routinely move between ponds over these distances.6.We conclude that breeding pond isolation is a primary determinant of the temporal and spatial dynamics of pond use by tungara frogs, and can result in spatial patterns in pond use that are independent of pond quality. These isolation effects are, however, unrelated to metapopulation processes, as most turnover in pond use is probably a result of dispersal and breeding site selection by individuals, and not resulting from the extinction of local populations.