Temporary pond ecosystem functioning shifts mediated by the exotic red swamp crayfish (<Emphasis Type="Italic">Procambarus clarkii</Emphasis>): a mesocosm study

Temporary ponds, acknowledged for their conservation value, are colonized by the invasive crayfish Procambarus clarkii. We have tested the consequences of this colonization for the ecosystem under two contrasted scenarios: one single individual arrival or three individuals arrival. We recreated the temporary pond ecosystem in 1 m² tanks to investigate the impact of the two crayfish densities. We studied the macrophyte community composition and abundance, chlorophyll a and total suspended solids concentrations, and the diversity and functional composition of micro-crustacean and macro-invertebrate communities. We observed a reduction of macrophyte biomass in experimental crayfish mesocosms in comparison with control tanks, nearly 80 and 40% less in 3 and 1 crayfish/m² tanks, respectively. The macrophyte community shifted, followed by a filamentous algae development, an increase of bare sediment and turbidity in crayfish tanks. The macro-invertebrate community suffered a richness loss of 28 and 22%, in 3 and 1 crayfish/m² tanks, respectively. Functionally, macro-invertebrate diversity reduction most strongly affected the grazer, detritivore and predator trophic groups. Microcrustaceans seemed not to be affected by the introduction of the crayfish. The introduction of the crayfish greatly altered the ecosystem structure and subsequently the ecosystem functioning.     

Characterization of benthic habitat settings in a lagoonal ecosystem using free-living nematodes as proxy

Free-living nematodes are sensitive to most of the disturbances and therefore have ability to reflect direct structural and functional changes in an ecosystem. We studied nematode assemblages of Chilika Lagoon, the largest lagoon of Asia, across spatio-temporal scales in link with environmental variables and evaluated nematode assemblages as a proxy to characterize lagoonal benthic habitat settings. Our results revealed that nematode communities showed significant variation spatially and temporally in terms of mean density (16–854/10 cm²) and mean number of species (7–74). Salinity is the key factor that controls nematode community structure across this lagoon and was strongly supported by statistical analyses. The observed nematode assemblages were further used as a proxy to assign benthic habitats of Chilika into distinct biological, topographical and hydrological settings. This study showed that nematode assemblages could be effectively used for long term ecological monitoring of dynamic sedimentary environment of lagoons globally.     

Mitochondrial DNA diversity and PCR-based sex determination of Irrawaddy dolphin (<Emphasis Type="Italic">Orcaella</Emphasis><Emphasis Type="Italic">brevirostris</Emphasis>) from Chilika Lagoon,India

Of the only known two Lagoon populations of Irrawaddy dolphins (Orcaella) in the world, one is residing in the Chilika Lagoon in Orissa state, India. In addition to accidental deaths in gill net fishery and mechanized boat operations, there has been exploitation of the species for their oil. Extreme patchy distribution and vulnerability to becoming entangled in fishing gear has made it a focus of conservation concern. Information on genetic diversity of populations has considerable potential for informing conservation plans. The present paper reports the first genetic study of O. brevirostris from Chilika Lagoon based on mtDNA sequencing and PCR-based sex identification from 11 individuals. Control region sequence comparison showed two haplotypes and cytochrome b a single haplotype in the Chilika population of the species. Phylogenetic analysis indicated distinct clades within the Asian samples, with the Indian population showing closest genetic proximity to the haplotypes from Thailand. Sex of the animal was determined by PCR-based method. It is important to continue to examine the population discreteness and genetic variation of Irrawaddy dolphin in Chilika Lagoon vis-à-vis its global geographic distribution for formulating the conservation plans of the species.     

Eutrophication decreases ecological resilience by reducing species diversity and altering functional traits of submerged macrophytes

Positive feedback is key to producing alternative stable states and largely determines ecological resilience in response to external perturbations. Understanding the positive feedback mechanisms in macrophyte-dominated lakes is crucial for resilience-based management and restoration. Based on the field investigation of submerged macrophyte communities in 35 lakes in China, we found that morphological complexity (MC) and morphological plasticity (MP) are correlated with the stoichiometric homeostasis of phosphorus (H_P) and are related to ecosystem structure, functioning, and stability. We also found that the positive feedback strength of lakes dominated by macrophytes is biomass- and diversity-dependent. Eutrophication can decrease the community biomass by decreasing community MC, MP, and H_P and the species diversity through low-light availability, ultimately decreasing the positive feedback strength and resilience of clear water states. We argue that functional traits and species diversity should be considered to build more resilient ecosystems in future changing environment scenarios.     

区域尺度城镇扩张的情景模拟与生态效应——以广西西江经济带为例

以快速城镇化的广西西江经济带为案例区,以生态重要性和开发建设适宜性为情景、利用最小累积阻力模型对城镇扩张进行模拟,进而从区域生态系统服务功能变化角度定量分析两种情景的生态效应差异。结果表明,经济带东西两翼地区生态重要性较高,中部地区开发建设适宜性较高。中小城镇在生态重要性情景中获得了较大的发展机遇,而大城市在开发建设适宜性情景下扩张更快。相同扩张强度下,生态重要性情景的区域生态系统服务功能总量下降较少,除食物生产功能外的其他各项服务功能呈现类似格局。随着扩张强度增加,两种情景下生态系统服务功能下降量之间的差异逐渐增大,从0.5%强度下的1.09亿元增大到10.0%强度下的4.05亿元。基于生态重要性的扩张情景对于保护生态环境、维持开发与保护之间的平衡更加有利,是一种相对合理的扩张方式。为开展区域层面城镇扩张情景模拟分析提供了参考,也为未来调控城镇扩展格局提供了优化情景和科学依据。     

Community-aggregated plant traits interact with soil nutrient heterogeneity to determine ecosystem functioning

Background and aims

Spatial distribution of soil nutrients (soil heterogeneity) and availability have strong effects on above- and belowground plant functional traits. Although there is ample evidence on the tight links between functional traits and ecosystem functioning, the role played by soil heterogeneity and availability as modulators of such relationship is poorly known.

Methods

We conducted a factorial experiment in microcosms containing grasses, legumes and non-legume forbs communities differing in composition to evaluate how soil heterogeneity and availability (50 and 100 mg N) affect the links between traits and ecosystem functioning. Community-aggregated specific leaf area (SLA_agg) and specific root length (SRL_agg) were measured as both relevant response traits to soil heterogeneity and availability, and significant effect traits affecting ecosystem functioning (i.e., belowground biomass, β-glucosidase and acid phosphatase activities, and in situ N availability rate).

Results

SRL_agg was negatively and significantly associated to β-glucosidase, phosphatase and N availability rate in the high nutrient availability and heterogeneous distribution scenario. We found a significant negative relationship between SLA_agg and availability rate of mineral-N under low nutrient availability conditions.

Conclusions

Soil heterogeneity modulated the effects of both traits and nutrient availability on ecosystem functioning. Specific root length was the key trait associated with soil nutrient cycling and belowground biomass in contrasted heterogeneous soil conditions. The inclusion of soil heterogeneity into the trait-based response-effect framework may help to scale from plant communities to the ecosystem level.     

Influence of bacterivorous nematodes on the decomposition of cordgrass

The influence of bacterivorous nematodes (Diplolaimelloides meyli, Diplolaimelloides oschei, Diplolaimella dievengatensis, Panagrolaimus paetzoldi) on the decomposition of a macrophyte (Spartina anglica) in an aquatic environment was investigated by using laboratory microcosm experiments. Several earlier studies have shown enhancement of the decomposition process in the presence of nematodes, but nematode species-specific effects were never tested. In this study four bacterivorous nematode species were applied separately to microcosms to investigate such species-specific influences.No stimulation of the decomposition process nor of the microbial community was observed in the presence of the nematodes, both were highest in the absence of nematodes. However, clear differences were found between nematode treatments. P. paetzoldi reached much higher numbers than the other species, causing a decrease in microbial activity, probably due to (over)grazing. Remarkably this low microbial activity did not result in a slow-down of the decomposition process compared to the other nematode treatments, raising the question whether P. paetzoldi might be able to directly assimilate detrital compounds. Other nematode species reached much lower densities, but nevertheless an influence on the decomposition process was observed. However, this experiment does not support the view that bacterivorous nematodes enhance decomposition rate.The experimental results show that in nematode communities the use of functional groups is inadequate for biodiversity studies. The four nematode species used in this study belong to the same functional group, but are clearly not functionally redundant since they all have a different influence on the cordgrass decomposition. This suggests that the relationship between nematode species diversity and ecosystem functioning may be idiosyncratic.     

Distribution and seasonal biomass of drift macroalgae in the Indian River Lagoon (Florida, USA) estimated with acoustic seafloor classification (QTCView, Echoplus)

Three areas of the Indian River Lagoon, Florida (USA) were surveyed to show seasonal changes in the distribution and biomass of macroalgae and seagrass. Acoustic seafloor discrimination based on first and second echo returns of a 50 kHz and 200 kHz signal, and two different survey systems (QTCView and ECHOplus) were used. System verification in both the field and a controlled environment showed it was possible to distinguish acoustically between seagrass, sparse algae, and dense algae. Accuracy of distinction of three classes (algae, seagrass, bare substratum) was around 60%. Maps were produced by regridding the survey area to a regular grid and using a nearest-neighbor interpolation to provide filled polygons. Biomass was calculated by counting pixels assigned to substratum classes with known wet-weight biomass values (sparse algae 250 g m^− 2, dense algae 2000 g m^− 2, seagrass 100 g m^− 2) that were measured in the field. In three study areas (Melbourne, Sebastian Inlet, and Cocoa Beach), a dependence of algal biomass on depth and season was observed. Seagrass most frequently occurred in water less than 1 m deep, and in November, seagrass beds tended to be covered by dense algae that also extended up- and downstream of shoals in the Lagoon. In March, the pattern was similar, with the exception that some areas of previously dense algae had started thinning into sparse algae. Macrophyte biomass was lowest in May in the Melbourne and Cocoa Beach study areas, with the opposite situation in the Sebastian Inlet study area. In May, seagrass areas were largely devoid of dense algae and most algae accumulations were sparse. In August, dense algae covered large areas of the deep Lagoon floor while shoals were largely free of algae or had only sparse cover. We suggest this summer pattern to reflect moribund algae being washed from the shallows to deeper channels and from there being removed from the lagoonal ecosystem either through tidal passages into the open ocean or by degradation and breakdown in situ. The differences between the study areas indicate high spatial and temporal variability in biomass and distribution of macrophyte biomass in the Indian River Lagoon.     

On the Importance of Shrub Encroachment by Sprouters, Climate, Species Richness and Anthropic Factors for Ecosystem Multifunctionality in Semi-arid Mediterranean Ecosystems

One of the most important changes taking place in drylands worldwide is the increase of the cover and dominance of shrubs in areas formerly devoid of them (shrub encroachment). A large body of research has evaluated the causes and consequences of shrub encroachment for both ecosystem structure and functioning. However, there are virtually no studies evaluating how shrub encroachment affects the ability of ecosystems to maintain multiple functions and services simultaneously (multifunctionality). We aimed to do so by gathering data from ten ecosystem functions linked to the maintenance of primary production and nutrient cycling and storage (organic C, activity of β-glucosidase, pentoses, hexoses, total N, total available N, amino acids, proteins, available inorganic P, and phosphatase activity), and summarizing them in a multifunctionality index (M). We assessed how climate, species richness, anthropic factors (distance to the nearest town, sandy and asphalted road, and human population in the nearest town at several historical periods) and encroachment by sprouting shrubs impacted both the functions in isolation and M along a regional (ca. 350 km) gradient in Mediterranean grasslands and shrublands dominated by a non-sprouting shrub. Values of M were higher in those grasslands and shrublands containing sprouting shrubs (43 and 62%, respectively). A similar response was found when analyzing the different functions in isolation, as encroachment by sprouting shrubs increased functions by 2–80% compared to unencroached areas. Encroachment was the main driver of changes in M along the regional gradient evaluated, followed by anthropic factors and species richness. Climate had little effects on M in comparison to the other factors studied. Similar responses were observed when evaluating the functions in isolation. Overall, our results showed that M was higher at sites with higher sprouting shrub cover, longer distance to roads and higher perennial plant species richness. Our study is the first documenting that ecosystem multifunctionality in shrublands is enhanced by encroaching shrubs differing in size and leaf attributes. Our findings reinforce the idea that encroachment effects on ecosystem functioning cannot be generalized, and that are largely dependent on the traits of the encroaching shrub relative to those of the species being replaced.     

Predicting Ecosystem Wide Impacts of Wallaby Management Using a Fuzzy Cognitive Map

At Booderee National Park, south-eastern Australia, the intensive control of the introduced red fox (Vulpes vulpes) resulted in a major increase in the abundance of a browsing macropod, the swamp wallaby (Wallabia bicolor). This has led to a major decrease in the abundance and biomass of a range of palatable plant species. Fox control has also started a trophic cascade that has resulted in a decline in the abundance of the greater glider (Petauroides volans) a folivorous arboreal marsupial, mediated either through increased predation by owls or increased competition with common brushtail possums (Trichosurus vulpecula). We identified five potential scenarios for managing the effects of over-abundant swamp wallabies on the ecosystem as a whole. These were (1) the present scenario of continued intensive fox control and four possible scenarios to redress the problem: (2) ceasing fox control; (3) intensive fox control and intensive wallaby control; (4) introducing dingoes and ceasing fox control; and (5) introducing dingoes and maintaining fox control. We used an ecosystem modelling approach based on a fuzzy cognitive map (FCM) to predict relative estimates of abundance for each scenario for a wide range of taxa in the Booderee National Park ecosystem likely to be affected by each scenario. We addressed uncertainty in our knowledge of the interactions between species by creating alternative models of the system by removing one or more of the uncertain links between species and varying the strength of the remaining interactions in the FCM and aggregated predictions from 100,000 models to estimate the effect of uncertainty on the predictions from our FCM model. In comparison with the current scenario of intensive fox control, scenario 3 had the greatest likelihood of improving the status of palatable plants. Scenarios 2 and 4 reduced the abundance of a range of medium-sized mammals but improved the status of greater gliders, whereas the predicted effects of scenario 5 were uncertain. The FCM modelling approach developed here provided a valuable tool for managers to learn about the potential ecosystem wide effects of management actions while incorporating the likely effects of uncertain knowledge on system outcomes.     

Invasive Crayfish Threaten the Development of Submerged Macrophytes in Lake Restoration

Submerged macrophytes enhance water transparency and aquatic biodiversity in shallow water ecosystems. Therefore, the return of submerged macrophytes is the target of many lake restoration projects. However, at present, north-western European aquatic ecosystems are increasingly invaded by omnivorous exotic crayfish. We hypothesize that invasive crayfish pose a novel constraint on the regeneration of submerged macrophytes in restored lakes and may jeopardize restoration efforts. We experimentally investigated whether the invasive crayfish (Procambarus clarkii Girard) affects submerged macrophyte development in a Dutch peat lake where these crayfish are expanding rapidly. Seemingly favourable abiotic conditions for macrophyte growth existed in two 0.5 ha lake enclosures, which provided shelter and reduced turbidity, and in one lake enclosure iron was added to reduce internal nutrient loading, but macrophytes did not emerge. We transplanted three submerged macrophyte species in a full factorial exclosure experiment, where we separated the effect of crayfish from large vertebrates using different mesh sizes combined with a caging treatment stocked with crayfish only. The three transplanted macrophytes grew rapidly when protected from grazing in both lake enclosures, demonstrating that abiotic conditions for growth were suitable. Crayfish strongly reduced biomass and survival of all three macrophyte species while waterfowl and fish had no additive effects. Gut contents showed that crayfish were mostly carnivorous, but also consumed macrophytes. We show that P. clarkii strongly inhibit macrophyte development once favourable abiotic conditions for macrophyte growth are restored. Therefore, expansion of invasive crayfish poses a novel threat to the restoration of shallow water bodies in north-western Europe. Prevention of introduction and spread of crayfish is urgent, as management of invasive crayfish populations is very difficult.     

Patterning limnological characteristics of the Chilika lagoon (India) using a self-organizing map

In this study, a self-organizing map (SOM) was utilized to classify habitats in the Chilika lagoon located in India, the largest lagoon ecosystem in Asia (maximum length, 64.3 km; mean width, 20.1 km). The lagoon was marginally eutrophic (nitrate, 0.25 ± 0.22 mg L⁻¹; orthophosphate, 0.26 ± 0.22 mg L⁻¹; n = 1,980, respectively) for six years (1999–2004), and it used to be warm, shallow, turbid and predominantly brackish. The SOM model successfully identified the changing patterns of limnology in the lagoon using the monthly limnological dataset from 30 study sites (July 1999–December 2004). Comparative re-sectoring evaluation of current monitoring sites was accomplished based on the outcome of the modeling. The new site clustering that emerged from the model was similar to conventional ones, and several sites were reorganized. Water physicochemistry was affected by freshwater inflow during monsoon and the new lagoon mouth constructed in September 2000, which resulted in variations in site characteristics in terms of limnology. The results of this study may provide information on the limnological patterns in Chilika lagoon, and they leave room for further study into functional changes in the lagoon ecology with respect to changes in climatic factor, freshwater flow and lagoon morphology.     

Effects of species evenness and dominant species identity on multiple ecosystem functions in model grassland communities

Ecosystems provide multiple services upon which humans depend. Understanding the drivers of the ecosystem functions that support these services is therefore important. Much research has investigated how species richness influences functioning, but we lack knowledge of how other community attributes affect ecosystem functioning. Species evenness, species spatial arrangement, and the identity of dominant species are three attributes that could affect ecosystem functioning, by altering the relative abundance of functional traits and the probability of synergistic species interactions such as facilitation and complementary resource use. We tested the effect of these three community attributes and their interactions on ecosystem functions over a growing season, using model grassland communities consisting of three plant species from three functional groups: a grass (Anthoxanthum odoratum), a forb (Plantago lanceolata), and a N-fixing forb (Lotus corniculatus). We measured multiple ecosystem functions that support ecosystem services, including ecosystem gas exchange, water retention, C and N loss in leachates, and plant biomass production. Species evenness and dominant species identity strongly influenced the ecosystem functions measured, but spatial arrangement had few effects. By the end of the growing season, evenness consistently enhanced ecosystem functioning and this effect occurred regardless of dominant species identity. The identity of the dominant species under which the highest level of functioning was attained varied across the growing season. Spatial arrangement had the weakest effect on functioning, but interacted with dominant species identity to affect some functions. Our results highlight the importance of understanding the role of multiple community attributes in driving ecosystem functioning.     

不同SSP-RCP情景下中国生态系统服务价值评估

定量评估生态系统服务价值是人类合理利用和管理生态系统的重要依据,未来气候情景下土地利用变化模拟及其对生态系统服务价值的影响评估对于区域生态系统服务管理、开展生态功能区划及减缓和适应气候变化等方面具有重要意义。基于最新IPCC共享社会经济路径(SSPs)和典型浓度路径(RCPs)的科学组合情景模拟得到的土地利用情景数据,对2020—2050年我国生态系统服务价值进行估算,并对2050年生态系统服务间的权衡与协同关系进行讨论,主要得到以下结论：生态系统服务价值(ESV)在2020—2050年表现为SSP1-RCP2.6>SSP2-RCP4.5>SSP3-RCP6.0,SSP1-RCP2.6情景下2020年ESV为12.39×10⁴亿元,2050年ESV为12.34×10⁴亿元;SSP2-RCP4.5情景下2020年ESV为12.17×10⁴亿元,2050年ESV为12.11×10⁴亿元;SSP3-RCP6.0情景下2020年ESV为12.02×10⁴亿元,2050年ES...     

Toxicity of rhizomes of the invasive Hedychium coronarium (Zingiberaceae) on aquatic species

The production and release of chemical compounds by invasive plants can affect competitors and native species overall, destabilizing ecological interactions and harming ecosystem functioning. Hedychium coronarium is an invasive macrophyte common on Brazilian riparian areas that produces a wide variety of allelochemicals, but little is known about their effect on aquatic species. Here, we identified the major chemical compounds of the aqueous extract of H. coronarium rhizomes and assessed its toxicity, evaluating the growth inhibition of one alga (Raphidocelis subcapitata) and one macrophyte (Lemna minor), and the lethality of cladoceran (Ceriodaphnia silvestrii and Daphnia similis) and Chironomidae larvae (Chironomus sancticaroli). The majoritarian compounds of H. coronarium rhizomes were Coronarin D and Coronarin D Ethyl Ether. The aqueous extract was toxic for all tested species. We observed growth inhibition in R. subcapitata, as well as reduction in biomass in L. minor. Chironomus sancticaroli and cladoceran were the most sensible species. The aqueous extract of H. coronarium rhizomes was toxic on tested conditions, suggesting that the rhizome compounds may interfere on aquatic organisms and in the dynamic of trophic webs of aquatic ecosystems on invaded areas.

     

Ecosystem services transcend boundaries: estuaries provide resource subsidies and influence functional diversity in coastal benthic communities

Background

Estuaries are highly productive ecosystems that can export organic matter to coastal seas (the ‘outwelling hypothesis’). However the role of this food resource subsidy on coastal ecosystem functioning has not been examined.

Methodology/Principal Findings

We investigated the influence of estuarine primary production as a resource subsidy and the influence of estuaries on biodiversity and ecosystem functioning in coastal mollusk-dominated sediment communities. Stable isotope values (δ¹³C, δ¹⁵N) demonstrated that estuarine primary production was exported to the adjacent coast and contributed to secondary production up to 4 km from the estuary mouth. Further, isotope signatures of suspension feeding bivalves on the adjacent coast (Dosinia subrosea) closely mirrored the isotope values of the dominant bivalves inside the estuaries (Austrovenus stutchburyi), indicating utilization of similar organic matter sources. However, the food subsidies varied between estuaries; with estuarine suspended particulate organic matter (SPOM) dominant at Tairua estuary, while seagrass and fringing vegetation detritus was proportionately more important at Whangapoua estuary, with lesser contributions of estuarine SPOM. Distance from the estuary mouth and the size and density of large bivalves (Dosinia spp.) had a significant influence on the composition of biological traits in the coastal macrobenthic communities, signaling the potential influence of these spatial subsidies on ecosystem functioning.

Conclusions/Significance

Our study demonstrated that the locations where ecosystem services like productivity are generated are not necessarily where the services are utilized. Further, we identified indirect positive effects of the nutrient subsidies on biodiversity (the estuarine subsidies influenced the bivalves, which in turn affected the diversity and functional trait composition of the coastal sediment macrofaunal communities). These findings highlight the importance of integrative ecosystem-based management that maintains the connectivity of estuarine and coastal ecosystems.     

Forecasting sagebrush ecosystem components and greater sage-grouse habitat for 2050: Learning from past climate patterns and Landsat imagery to predict the future

Sagebrush (Artemisia spp.) ecosystems constitute the largest single North American shrub ecosystem and provide vital ecological, hydrological, biological, agricultural, and recreational ecosystem services. Disturbances have altered and reduced this ecosystem historically, but climate change may ultimately represent the greatest future risk. Improved ways to quantify, monitor, and predict climate-driven gradual change in this ecosystem is vital to its future management. We examined the annual change of Daymet precipitation (daily gridded climate data) and five remote sensing ecosystem sagebrush vegetation and soil components (bare ground, herbaceous, litter, sagebrush, and shrub) from 1984 to 2011 in southwestern Wyoming. Bare ground displayed an increasing trend in abundance over time, and herbaceous, litter, shrub, and sagebrush showed a decreasing trend. Total precipitation amounts show a downward trend during the same period. We established statistically significant correlations between each sagebrush component and historical precipitation records using a simple least squares linear regression. Using the historical relationship between sagebrush component abundance and precipitation in a linear model, we forecasted the abundance of the sagebrush components in 2050 using Intergovernmental Panel on Climate Change (IPCC) precipitation scenarios A1B and A2. Bare ground was the only component that increased under both future scenarios, with a net increase of 48.98 km² (1.1%) across the study area under the A1B scenario and 41.15 km² (0.9%) under the A2 scenario. The remaining components decreased under both future scenarios: litter had the highest net reductions with 49.82 km² (4.1%) under A1B and 50.8 km² (4.2%) under A2, and herbaceous had the smallest net reductions with 39.95 km² (3.8%) under A1B and 40.59 km² (3.3%) under A2. We applied the 2050 forecast sagebrush component values to contemporary (circa 2006) greater sage-grouse (Centrocercus urophasianus) habitat models to evaluate the effects of potential climate-induced habitat change. Under the 2050 IPCC A1B scenario, 11.6% of currently identified nesting habitat was lost, and 0.002% of new potential habitat was gained, with 4% of summer habitat lost and 0.039% gained. Our results demonstrate the successful ability of remote sensing based sagebrush components, when coupled with precipitation, to forecast future component response using IPCC precipitation scenarios. Our approach also enables future quantification of greater sage-grouse habitat under different precipitation scenarios, and provides additional capability to identify regional precipitation influence on sagebrush component response.     

Climate Change-Induced Range Expansion of a Subterranean Rodent: Implications for Rangeland Management in Qinghai-Tibetan Plateau

Disturbances, both human-induced and natural, may re-shape ecosystems by influencing their composition, structure, and functional processes. Plateau zokor (Eospalax baileyi) is a typical subterranean rodent endemic to Qinghai-Tibetan Plateau (QTP), which are considered ecosystem engineers influencing the alpine ecosystem function. It is also regarded as a pest aggravating the degradation of overgrazed grassland and subject to regular control in QTP since 1950s. Climate change has been predicted in this region but little research exists exploring its impact on such subterranean rodent populations. Using plateau zokor as a model, through maximum entropy niche-based modeling (Maxent) and sustainable habitat models, we investigate zokor habitat dynamics driven by the future climate scenarios. Our models project that zokor suitable habitat will increase by 6.25% in 2050 in QTP. The predication indicated more threats in terms of grassland degradation as zokor suitable habitat will increase in 2050. Distribution of zokors will shift much more in their southern range with lower elevation compare to northern range with higher elevation. The estimated distance of shift ranges from 1 km to 94 km from current distribution. Grassland management should take into account such predictions in order to design mitigation measures to prevent further grassland degradation in QTP under climate change scenarios.