Jan Szolgay
@stuba.sk
Faculty of Civil Engineering, Dept. of Land and Water Resources Management
Slovak University of Technology
RESEARCH INTERESTS
Hydrology
Scopus Publications
Scopus Publications
Bence Bolla, Miklós Manninger, Tamás Molnár, Bálint Horváth, Jan Szolgay, Zoltán Gribovszki, Péter Kalicz, and András Szabó
MDPI AG
The effects of the changing frequency and severity of drought events in Central Europe may become a growing concern for its forests. In this study, we looked into how Hungary’s forests have been affected by the 2022 compound heatwave and drought, following an arid period from 2018 to 2021. We used our active intensive monitoring plots of the Forest Protection Measuring and Monitoring System (Level II in the ICP Forests) across the country between 2017 and 2022. We analyzed satellite images to support a survey of the large-scale drought utilizing moderate and high-resolution data. The health state of the forest calculated and mapped on the NDVI, ZNDVI, and NDWI indices showed damage and regeneration throughout the period studied. Overall, the forest stands observed tolerated the negative impacts of the drought (126–204 mm water deficit in 2022) based on our biomass data (the summer leaf loss was 14% in each monitoring plot). However, the classified Z-NDVI values of the Sentinel-2 satellite imagery for the period 2017–2022 showed a severe drought in 2022, which was followed by some improvement in 2023.
Anna Liová, Roman Výleta, Kamila Hlavčová, Silvia Kohnová, Tomáš Bacigál, Jana Poórová, and Ján Szolgay
Akademiai Kiado Zrt.
AbstractDesign flood hydrographs are often used to project safe and cost-effective hydraulic structures. This study proposes a system based on a combination of empirical and statistical approaches for constructing synthetic design flood hydrographs, that practitioners can easily apply. The system uses scaled observed seasonal flood hydrographs and respects the dependence structure among the flood peaks, volumes, and durations deduced from the set of seasonal flood hydrographs observed. The method was developed and tested based on data from the Horné Orešany reservoir in Slovakia.
András Herceg, Péter Kalicz, Katalin Anita Zagyvainé Kiss, Ján Szolgay, László Horváth, Bence Gallai, and Zoltán Gribovszki
Akademiai Kiado Zrt.
Az Európát is érintő jelenlegi, napjainkban zajló éghajlatváltozás statisztikailag szignifikáns felmelegedési tendenciával jellemezhető. Az éghajlatváltozás hatása a csapadékviszonyok és az evapotranszspirációs folyamatok megváltoztatásán keresztül érinti a vízkörforgalmat, így a csapadék eloszlásának és mennyiségének várható változásai a folyamatosan emelkedő hőmérséklettel együtt a növények nagyobb vízfelhasználását eredményezhetik, ami változásokat indukálhat a talajnedvességben, a talajvízben és ennek következtében a vízmérlegben. Az emelkedő hőmérséklet hatására a jövőben a növekvő transzspirációs igény valószínűleg a növényi közösségek fokozott talajvízfelvételét eredményezi, ami a talajvízszint további csökkenését is magával vonhatja. Ha ez bekövetkezik, a talajvízfüggő erdei közösségek regenerálódása ezeken a területeken kérdésessé válik, mivel a fiatal fák gyökérzete nem fogja tudni elérni a vízforrást. Következésképpen a Kárpát-medence sík vidékein és vizes élőhelyein a nagy vízigényű erdők fennmaradása kérdésessé válhat. A fás vegetáció számára kiemelten fontos a talajvíz szerepe a vegetációs időszakban, éppen ezért a talajvízszint változását régóta, rendszeresen monitorozzák.Konkrét megoldás lehet az árhullámok visszaduzzasztásából származó vízpótlás. A pozitív vízpótlási beavatkozásokra példa a Kaszó LIFE projekt. A projekt célja a leromlott élőhelyek rehabilitációja volt, ami a kedvező ökológiai állapot stabilizálásával teszi lehetővé a hosszú távú megőrzést. A megvalósítás eszközeként tórehabilitációt és folyó-mederbordákat alkalmaztak, biztosítva a Szentai-erdő (Nyugat-belső-somogyi kistérség) erdeinek, kis lápjainak és gyepterületeinek vízellátás javítását.Jelen kutatás célja pedig a Kaszó LIFE projekt vízpótlási beavatkozásai után, azok felszín alatti vízszintre gyakorolt hidrológiai hatásainak elemzése volt. A meteorológiai adatok és a monitoring adatok alapján elmondható, hogy a Szentai-erdőben 30 éves szárazodási tendencia volt tapasztalható, amelynek elsődleges mutatója a talajvízszint csökkenése. Kiemelendőek a 2016–2017-es vizsgálati időszak évei, amikor az alapvetően lefolyástalan vizsgálati területen nem volt elegendő csapadék a talajvíz szintjének fenntartásához. Kutatási eredményeink azonban azt mutatták, hogy a vízpótlást célzó beavatkozások (mederbordák és tározótavak) összességében a talajvízszint emelkedését biztosítják.A két beavatkozási típus talajvízszint emelkedésére gyakorolt hatását vizsgálva arra a következtetésre jutottunk, hogy míg a tavak építése jelentősen befolyásolja a környező kutak vízszintjét, addig a mederbordák esetében kisebb mértékű a hatás.
Berit Arheimer, Christophe Cudennec, Attilio Castellarin, Salvatore Grimaldi, Kate V. Heal, Claire Lupton, Archana Sarkar, Fuqiang Tian, Jean-Marie Kileshye Onema, Stacey Archfield,et al.
Informa UK Limited
The new scientific decade (2023-2032) of the International Association of Hydrological Sciences (IAHS) aims at searching for sustainable solutions to undesired water conditions - may it be too little, too much or too polluted. Many of the current issues originate from global change, while solutions to problems must embrace local understanding and context. The decade will explore the current water crises by searching for actionable knowledge within three themes: global and local interactions, sustainable solutions and innovative cross-cutting methods. We capitalise on previous IAHS Scientific Decades shaping a trilogy; from Hydrological Predictions (PUB) to Change and Interdisciplinarity (Panta Rhei) to Solutions (HELPING). The vision is to solve fundamental water-related environmental and societal problems by engaging with other disciplines and local stakeholders. The decade endorses mutual learning and co-creation to progress towards UN sustainable development goals. Hence, HELPING is a vehicle for putting science in action, driven by scientists working on local hydrology in coordination with local, regional, and global processes.
András Szabó, Zoltán Gribovszki, Péter Kalicz, Ján Szolgay, Zsolt Gácsi, and Bence Bolla
Akademiai Kiado Zrt.
Az Alföldet, azon belül is különösen a Homokhátságot érintő talajvízszint süllyedés, súlyos ökológiai és gazdasági következményekkel is járó problémakör. A jelenség hátterében álló lehetséges okokkal kapcsolatban több évtizede zajlik kutatómunka, ugyanakkor ezek relatív súlyának meghatározása a mai napig tudományos vita tárgyát képezi.Több szerző is kiemeli az erdőtelepítések talajvízszint csökkentő hatásának fontosságát. Ez a hatás két módon, a vegetáció vízfelvétele, illetve a csapadékból történő utánpótlódás csökkentése (intercepció, talajnedvesség felvétel) által jelentkezhet. Ezen mechanizmusok működését vizsgáltuk meg egy akác (Robinia pseudoacacia) és egy fekete fenyő (Pinus nigra) állomány esetében a Homokhátságon, Kecskemét-Ménteleken kialakított mintaterületünkön, 90, 150 és 200 cm-es mélységben, nagy időbeli felbontással mért talajnedvesség, illetve talajvíz adatokra alapozva.Az adatok alapján feltételezhető, hogy a talajvízből nem történik közvetlen, vagy közvetett vízfelvétel, aminek oka vélhetően a gyökérzóna és a talajvíz közti igen jelentős horizontális távolság. A talajnedvesség esetében a sekélyebb rétegekben egyértelműen jelentkezik az erdőállományok szezonális szárító hatása. Ugyanakkor a mélyebb rétegek talajnedvesség adatai alapján kijelenthető, hogy a csapadékból történő talajvíz visszatöltődésre leginkább az akác állomány alatt van elméleti lehetőség. A látszólagos ellentmondás feltételezhetően a gyökérzet által kialakított makropórusok hatásával magyarázható. Ezt támasztja alá az akác és fekete fenyő állományok közti igen jelentős eltérés is.Következtetésünk, hogy az erdőállományok lokálisan jelentősen eltérő hatást gyakorolhatnak a talajvízszintre. Ezért a lezajló folyamatok hátterét, általános jellegű megállapítások helyett, az adott hidrológiai rendszer több elemét vizsgáló monitoring adataira alapozva lehetséges csak felderíteni.
András Szabó, Zoltán Gribovszki, Ján Szolgay, Péter Kalicz, Kitti Balog, József Szalai, Kamila Hlavčová, and Bence Bolla
MDPI AG
The process of groundwater evapotranspiration and its subsequent recharge are fundamental aspects of the Earth’s natural water cycle and have significant implications for the preservation and functionality of various forested ecosystems. This study presents a case analysis examining the recent fluctuations in groundwater levels and their replenishment in two wells situated at a designated forested experimental area and a control site. The magnitude and temporal fluctuations of groundwater recharge were examined through the utilisation of a novel adaptation of the traditional White method, which was specifically tailored to the local context. We also tested the sensitivity of the White method as an indicator of the system’s behaviour because the signal has changed in relation to the access of the forests to groundwater under the conditions of regionally declining groundwater resources and a warming climate. The novelty of this approach is found in the examination of the temporal fluctuations in groundwater recharge, which are influenced by both a decrease in groundwater levels caused by forest evaporation in response to climate change and a regional reduction in groundwater supplies. As a result, the ongoing decrease in groundwater levels may have significant adverse effects on local forests.
Miriam Bertola, Günter Blöschl, Milon Bohac, Marco Borga, Attilio Castellarin, Giovanni B. Chirico, Pierluigi Claps, Eleonora Dallan, Irina Danilovich, Daniele Ganora,et al.
Springer Science and Business Media LLC
Roman Výleta, Kamila Hlavčová, Silvia Kohnová, Tomáš Bacigál, Anna Liová, and Ján Szolgay
Central Library of the Slovak Academy of Sciences
Martin Kuban, Juraj Parajka, Rui Tong, Isabella Greimeister-Pfeil, Mariette Vreugdenhil, Jan Szolgay, Silvia Kohnova, Kamila Hlavcova, Patrik Sleziak, and Adam Brziak
Walter de Gruyter GmbH
Abstract In a previous study, the topsoil and root zone ASCAT satellite soil moisture data were implemented into three multi-objective calibration approaches of the TUW hydrological model in 209 Austrian catchments. This paper examines the model parametrization in those catchments, which in the validation of the dual-layer conceptual semi-distributed model showed improvement in the runoff simulation efficiency compared to the single objective runoff calibration. The runoff simulation efficiency of the three multi-objective approaches was separately considered. Inferences about the specific location and the physiographic properties of the catchments where the inclusion of ASCAT data proved beneficial were made. Improvements were primarily observed in the watersheds with lower slopes (median of the catchment slope less than 15 per cent) and a higher proportion of farming land use (median of the proportion of agricultural land above 20 per cent), as well as in catchments where the runoff is not significantly influenced by snowmelt and glacier runoff. Changes in the mean and variability of the field capacity parameter FC of the soil moisture regime were analysed. The values of FC decreased by 20 per cent on average. Consequently, the catchments’ water balance closure generally improved by the increase in catchment evapotranspiration during the validation period. Improvements in model efficiency could be attributed to better runoff simulation in the spring and autumn month. The findings refine recommendations regarding when hydrological modelling could consider satellite soil moisture data added to runoff signatures in calibration useful.
András Szabó, Zoltán Gribovszki, Péter Kalicz, Ján Szolgay, and Bence Bolla
Walter de Gruyter GmbH
Abstract The decline in groundwater levels is a cause of concern in many regions of the world, including the Sand Ridge of Hungary. The causes of the regional depletion range from rising air temperatures, changes in precipitation, domestic and agricultural groundwater use and past amelioration and recent afforestation, including the effects of drilling for crude oil exploration. The relations between the decline, the soil water regime and groundwater recharge under existing aged forests remained unclear thus far. Based on our monitoring of groundwater and soil moisture we aim to clarify this interplay in a new experimental site on the hilltop of the Sand Ridge. We compared three land-uses: a 41-year-old black locust (Robinia Pseudoacacia) offshoot forest, an 83-year-old first generation black pine (Pinus nigra) forest, and a grassland control site. The observed differences in the soil moisture profiles and dynamics were connected to the use of water by the given type of vegetation. We indicated a connection between the disruption of the groundwater recharge and the loss of contact of the rooting system of the forests with the deepening of the unconfined aquifer. Even if the aged forests could locally contribute to the decline, we conclude that the decline at the hilltop site that may be more strongly driven by other regional factors.
Pavel Raška, Nejc Bezak, Carla S.S. Ferreira, Zahra Kalantari, Kazimierz Banasik, Miriam Bertola, Mary Bourke, Artemi Cerdà, Peter Davids, Mariana Madruga de Brito,et al.
Elsevier BV
Martin Kubáň, Juraj Parajka, Ján Szolgay, Silvia Kohnová, Kamila Hlavčová, Patrik Sleziak, and Adam Brziak
Central Library of the Slovak Academy of Sciences
Anna Liová, Peter Valent, Kamila Hlavčová, Silvia Kohnová, Tomáš Bacigál, and Ján Szolgay
Central Library of the Slovak Academy of Sciences
Recent changes in climatic characteristics and consequent changes in the discharges and in the hydrological response of watersheds raise questions about the safety of water structures. Changes in flood wave characteristics (shape, volume, peak flow) may significantly affect the functionality of these structures. The study proposes a methodology for constructing design wave and flood hydrographs using discharge time series. A case study was carried out in the Little Carpathians watershed of the Parná River, above the profile of the Horné Orešany reservoir in Slovakia. The volumes and characteristic shapes of the flood waves with the maximum annual and seasonal discharges were determined using the Floodsep software. Subsequently, the T -year annual and seasonal discharges were estimated. Then, for pairs of the T year discharges and the associated volumes of flood waves, a joint probability distribution was constructed by copula functions. The associated volume of the T -year peak discharges was selected from the copula, and the probability of exceeding it was determined. Based on this analysis, a set of annual and seasonal control flood waves with the design maximum discharge, the associated volume with the selected probability, and the typical shape of the flood wave was constructed. This research provides satisfactory results for designing control waves necessary for assessing water structures with extreme loads and establishing a functional methodology for assessing other water structures in the region.
Patrik Sleziak, Roman Výleta, Kamila Hlavčová, Michaela Danáčová, Milica Aleksić, Ján Szolgay, and Silvia Kohnová
MDPI AG
The changing climate is a concern with regard to sustainable water resources. Projections of the runoff in future climate conditions are needed for long-term planning of water resources and flood protection. In this study, we evaluate the possible climate change impacts on the runoff regime in eight selected basins located in the whole territory of Slovakia. The projected runoff in the basins studied for the reference period (1981–2010) and three future time horizons (2011–2040, 2041–2070, and 2071–2100) was simulated using the HBV (Hydrologiska Byråns Vattenbalansavdelning) bucket-type model (the TUW (Technische Universität Wien) model). A calibration strategy based on the selection of the most suitable decade in the observation period for the parameterization of the model was applied. The model was first calibrated using observations, and then was driven by the precipitation and air temperatures projected by the KNMI (Koninklijk Nederlands Meteorologisch Instituut) and MPI (Max Planck Institute) regional climate models (RCM) under the A1B emission scenario. The model’s performance metrics and a visual inspection showed that the simulated runoff using downscaled inputs from both RCM models for the reference period represents the simulated hydrological regimes well. An evaluation of the future, which was performed by considering the representative climate change scenarios, indicated that changes in the long-term runoff’s seasonality and extremality could be expected in the future. In the winter months, the runoff should increase, and decrease in the summer months compared to the reference period. The maximum annual daily runoff could be more extreme for the later time horizons (according to the KNMI scenario for 2071–2100). The results from this study could be useful for policymakers and river basin authorities for the optimum planning and management of water resources under a changing climate.
Martin Kubáň, Juraj Parajka, Rui Tong, Isabella Pfeil, Mariette Vreugdenhil, Patrik Sleziak, Brziak Adam, Ján Szolgay, Silvia Kohnová, and Kamila Hlavčová
MDPI AG
The role of soil moisture is widely accepted as a significant factor in the mass and energy balance of catchments as a controller in surface and subsurface runoff generation. The paper examines the potential of a new dataset based on advanced scatterometer satellite remote sensing of soil moisture (ASCAT) for multiple objective calibrations of a dual-layer, conceptual, semi-distributed hydrological model. The surface and root zone soil moisture indexes based on ASCAT data were implemented into calibration of the hydrological model. Improvements not only in the instrument specifications, i.e., better temporal and spatial sampling, but also in the higher radiometric accuracy and retrieval algorithm, were applied. The analysis was performed in 209 catchments situated in different physiographic and climate zones of Austria for the period 2007–2018. We validated the model for two validation periods. The results show that multiple objective calibrations have a substantial positive effect on constraining the model parameters. The combined use of soil moisture and discharges in the calibration improved the soil moisture simulation in more than 73% of the catchments, except for the catchments with higher forest cover percentages. Improvements also occurred in the runoff model efficiency, in more than 27% of the catchments, mostly in the watersheds with a lower mean elevation and a higher proportion of farming land use, as well as in the Alpine catchments where the runoff is not significantly influenced by snowmelt and glacier runoff.
Adam Brziak, Martin Kubáň, Silvia Kohnová, and Ján Szolgay
Central Library of the Slovak Academy of Sciences
Péter Csáki, Kitti Gyimóthy, Péter Kalicz, Ján Szolgay, Katalin Anita Zagyvai-Kiss, and Zoltán Gribovszki
Walter de Gruyter GmbH
AbstractProviding information on the impacts of climate change on hydrological processes is becoming ever more critical. Modelling and evaluating the expected changes of the water resources over different spatial and time scales can be useful in several fields, e.g. agriculture, forestry and water management. Previously a Budyko-type spatially distributed long-term climate-runoff model was developed for Hungary. This research includes the validation of the model using historical precipitation and streamflow measurements for three nested sub-catchments of the Zala River Basin (Hungary), an essential runoff contributing region to Lake Balaton (the largest shallow lake in Central Europe). The differences between the calculated (from water balance) and the estimated (by the model) mean annual evapotranspiration varied between 0.4% and 3.6% in the validation periods in the sub-catchments examined. Predictions of the main components of the water balance (evapotranspiration and runoff) for the Zala Basin are also presented in this study using precipitation and temperature results of 12 regional climate model simulations (A1B scenario) as input data. According to the projections, the mean annual temperature will be higher from period to period (2011–2040, 2041–2070, 2071–2100), while the change of the annual precipitation sum is not significant. The mean annual evapotranspiration rate is expected to increase slightly during the 21st century, while for runoff a substantial decrease can be anticipated which may exceed 40% by 2071–2100 relative to the reference period (1981–2010). As a result of this predicted reduction, the runoff from the Zala Basin may not be enough to balance the increased evaporation rate of Lake Balaton, transforming it into a closed lake without outflow.
Ján Szolgay, Günter Blöschl, Zoltán Gribovszki, and Juraj Parajka
Walter de Gruyter GmbH
AbstractThe paper introduces the Special Section on the Hydrology of the Carpathians in this issue. It is the result of an initiative of the Department of Land and Water Resources Management of the Slovak University of Technology in Bratislava, the Institute of Hydraulic Engineering and Water Resources Management of the TU Vienna and the Institute of Geomatics and Civil Engineering of the University of Sopron to allow young hydrologists in the Carpathian Basin (and from outside) to present their research and re-network on the emerging topics of the hydrology of the Carpathians at the HydroCarpath Conferences since 2012.
Lenka Slavíková, Pavel Raška, Kazimierz Banasik, Marton Barta, Andras Kis, Silvia Kohnová, Piotr Matczak, and Ján Szolgay
Informa UK Limited
ABSTRACT Flood recovery is an important period in the flood risk management cycle. Recently, flood recovery has become viewed as an opportunity for future flood damage mitigation. Financial flows to cover flood damages and rules regarding their allocation are crucial for supporting or undermining mitigation efforts. In this paper, we map and compare state flood recovery funding in the so-called Visegrad Group Countries (V4), i.e. Czechia, Hungary, Poland and Slovakia, over the past 30 years of their democratic history. We apply a qualitative comparative approach to identify differences and similarities in risk sharing and state flood recovery funding approaches among these countries. Additionally, we reveal how risk sharing is addressed by existing flood recovery funding schemes. The results indicate that national governments have a low willingness to institutionalise ex-ante compensation schemes. Ad hoc instruments initiated shortly after disastrous flooding usually do not provide incentives to reduce future flood damages.
P. Sleziak, J. Szolgay, K. Hlavčová, M. Danko, and J. Parajka
Elsevier BV
Abstract In the current changing climate, the importance of temporal stability of hydrological models is increasing. The objective of this paper is to assess the effects of the changing weight of snow (wS) in a multiple objective calibration of a conceptual hydrological model in terms of the temporal stability of runoff and snow model efficiency and hydrologic model parameters. The methodology was tested by a lumped conceptual hydrological model (the TUW model), which was calibrated and validated in 213 Austrian catchments in two climatically different decades (i.e., 1981–1990 and 2001–2010). The results indicate that the runoff and snow model efficiencies are almost insensitive to a large range of wS, i.e., from 0 to 0.9 for the runoff and from 0.75 to 1.0 for the snow. This relationship is similar in the two different decades; however, the calibration runoff model efficiency (i.e., Nash-Sutcliffe efficiency) was about 5 to 10% greater in flatland catchments in the warmer decade (2001–2010). The main impact of wS on the snow model efficiency is the reduction of snow underestimation errors in the flatland catchments. The relative improvement of the snow simulations in the validation periods is greater in the flatland catchments and is in a range of 45–60% compared to 13% and 31% in the alpine catchments. The evaluation of the temporal stability indicates that increasing the weight of the snow increases the temporal stability of the degree-day factor and the parameters of the snowfall and rainfall thresholds. A change in the weight of the snow has the greatest impact on glacerized catchments, which were the most sensitive to changes in the mean annual air temperature between the two decades.
Adam Brziak, Martin Kubáň, Silvia Kohnová, and Ján Szolgay
Central Library of the Slovak Academy of Sciences
The accurate modelling of discharges in catchments plays an important role in solving a large variety of water management tasks. Three basic errors may affect the outputs modelled: the quality of the input data, uncertainities about the parameters, and the structure of the model. This paper is focused on a comparison of the performances of the lumped and semidistributed versions of the conceptual TUW rainfall-runoff model, which represents two different model structures. The comparison took place on 180 Austrian catchments, which have variable morphologies, altitudes, land uses, etc. We focused on the variability of the efficiencies and parameters of both types of HBV models, which were calibrated based on discharges in the period from 1991 to 2000. Whether the morphology and mean elevation of the catchment affect the calibration results was also take in account. Finally, we realized that the semi-distributed version of the TUW model gave better results as to the calibration efficiencies, when we calibrated the model for discharges; at the same time, the variations in the model parameters also gave better results in the semi-distributed version of the TUW model.
Günter Blöschl, Julia Hall, Alberto Viglione, Rui A. P. Perdigão, Juraj Parajka, Bruno Merz, David Lun, Berit Arheimer, Giuseppe T. Aronica, Ardian Bilibashi,et al.
Springer Science and Business Media LLC
Climate change has led to concerns about increasing river floods resulting from the greater water-holding capacity of a warmer atmosphere1. These concerns are reinforced by evidence of increasing economic losses associated with flooding in many parts of the world, including Europe2. Any changes in river floods would have lasting implications for the design of flood protection measures and flood risk zoning. However, existing studies have been unable to identify a consistent continental-scale climatic-change signal in flood discharge observations in Europe3, because of the limited spatial coverage and number of hydrometric stations. Here we demonstrate clear regional patterns of both increases and decreases in observed river flood discharges in the past five decades in Europe, which are manifestations of a changing climate. Our results—arising from the most complete database of European flooding so far—suggest that: increasing autumn and winter rainfall has resulted in increasing floods in northwestern Europe; decreasing precipitation and increasing evaporation have led to decreasing floods in medium and large catchments in southern Europe; and decreasing snow cover and snowmelt, resulting from warmer temperatures, have led to decreasing floods in eastern Europe. Regional flood discharge trends in Europe range from an increase of about 11 per cent per decade to a decrease of 23 per cent. Notwithstanding the spatial and temporal heterogeneity of the observational record, the flood changes identified here are broadly consistent with climate model projections for the next century4,5, suggesting that climate-driven changes are already happening and supporting calls for the consideration of climate change in flood risk management.Analysis of a comprehensive European flood dataset reveals regional changes in river flood discharges in the past five decades that are consistent with models suggesting that climate-driven changes are already happening.