Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. in Li Qiang streams subtropical in assemblages of fish homogenization/differentiation biotic induce dams Low-head r ot asn h omto f“oe omnte”(ob ta. 06,adsc nvlcommunities” “novel such and others 2006), and al., established ramifications. et become evolutionary (Hobbs species and communities” new ecological ( “novel as ( notable of localities occur locality have formation to among each will continue the in composition will causing Changes species species lost, 2018). of are in al., Zhang number et similarity 2014; Olden the the al., 2014; only Vill´eger also 2011, et 2014; not but al., resulting alter 2003) et species, disturbances (Toussaint Gaines, cosmopolitan These biodiversity with Anthropogenic current 2019). species the al., or 2004). endemic of et differentiation), Poff, of reconfiguration replacement (i.e., & dramatic the a increasing Olden of in homogenization), 1999; species rates of (i.e., Lockwood, the effects decreasing accelerate & combined disturbances the in (McKinney by result dissimilarities driven composition can assemblage species unchanged gains in species Changes communi- among and Olden, 2004). dissimilarity Poff, 1999; compositional losses & in Lockwood, (Olden increase & time an (McKinney increase over describes time an ties differentiation over by biotic communities characterized contrast, among 2015), In al., composition 2006). et species (McGill of Anthropocene similarity the the of in fingerprint a is homogenization Biotic INTRODUCTION 1. homogenization Biotic fish, Stream qualitative diversities dam, the Low-head functional otherwise, and Keywords: Taxonomic scales; contradictory. differentiation, spatial or and erroneous small be at may assemblages conclusions de- fish abundance-based quantitative strong of and of importance the homogenization/differentiation the demonstrates highlights structuring study and homogenization/differentiation fish in this in approaches conclusion, of patterns perceived In patterns perceived of nuanced type aspects. of data detect functional patterns on could and pendence in differentiation; taxonomic latter variation taxonomic for the considerable differentiation that of exhibited and suggesting degree pairs homogenization aspects, partial the functional Additionally, overestimated for that homogenization/differentiation. significantly verified than functional was former higher trend was the opposite approaches of that for an incidence-based however, homogenization outcome suggesting using functional ones, the differentiation weak taxonomic abundance-based whether by of using accompanied and ex- extent was differentiation The metrics, and was Taxonomic whether approaches approaches. functional China, examine incidence-based abundance-based and approaches. to Mountains, for taxonomic abundance-based differentiation aimed Wannan We between functional or the ceeded homogeneity/heterogeneity. differed incidence-based in assemblage similarity on fish basins assemblage depended on four homogenization/differentiation re- fish dams similarity, from in low-head community Data of changes modify effects the species the increase. evaluate endemic or to of used decrease extirpation community-distinctiveness and in species sulting cosmopolitan of introduction Human-mediated Abstract 2021 6, July 4 3 2 1 olg fFseis ca nvriyo China University of Normal University Anhui University Ocean Normal Fisheries, Anhui of Environment, College and Ecology of School colo clg n niomn,AhiNra University Normal Anhui Environment, and Ecology of School 1 uhuZhang Yuzhou , 1 ulnWang Ruolan , 2 igChu Ling , 1 2 uuLi Yuru , 3 n uziYan Yunzhi and , β- iest)(ilee tal., (Vill´eger et diversity) α- iest)(a & (Sax diversity) 4 Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. ae naudnedt a eevdls teto nra clgclasmlgs(u e asye al., et Cassey see (but assemblages 2020). ecological al., real species et in rare Dai attention in 2019; differentiation differences less al., or stochastic this received et homogenization when In has Liu biotic especially 2019). 2008; data 2020), of al., data abundance al., quantification et incidence-based et the on Unfortunately, of Liu Dai based undersampling. 2019; accuracy 2008; al., of the al., et artifacts questioned et Liu are recently (Cassey 2015; have drastically time al., ecologists changes et over of (Barwell abundance composition number perceived considerable species species (i.e., a in how context, outcomes changes some on contrasting in to depending Furthermore, in relative 2019). result homogenization) can enough al., may perceived index et also Liu similarity and indices 2007; of homogenization McKinney, abundance-based if & choice and instance, homogenization Sorte For the incidence-based biotic (La 2019). in overlooked case, that al., species are et the shown dominant data Liu of in has 2008; abundance functions al., species species evidence the et underestimate (Cassey different of may computed communities approaches across body similarity which incidence-based biological to substantially distributed growing of degree differ a magnitude equally the may the affect and not influence also species composition, can is same abundance in the individuals population of differ in of 2019; changes abundance) al., number Therefore, (i.e., et locations. the Liu size same 2008; population and al., the et locations, (Cassey Indeed, extents across abundance 2020). spatial species al., small in in et primarily abundance Dai differ differentiated may role with structuring weightings composition crucial in to regional species sensitivity a or due when higher global play patterns exhibit on heterogeneous may may apart or approaches far dissimilarity homogeneous geographically abundance-based incidence-based However, are and that 2014). compositions (Legendre, shown species scales 2020; documentary have in Mandrak, and focused mostly studies & sampling differ Campbell homogenization Previous communities 2018; on biotic al., when 2020). limitation et of homogenization al., (Olden the extent data) et taxonomic to abundance and of due Daga quantify pattern lack (i.e., perhaps the to data data, abundance on Olden used for occurrence studies in accessibility been species (reviewed Most on have homogenization 2014). exclusively approaches Reshi, biotic almost & of numerous context Dar currently the in and (reviewed in 2018), animals of studied al., consequences most potential et the combination the are of the complementary fishes understanding pressure. Assessing Freshwater is under better 2014). dissimilarity functioning a al., Penczak, functional ecosystem permit (Vill´eger et on in & will (G dissimilarity change lowacki changes diversities used biodiversity taxonomic functional of is in and analysis approach changes taxonomic the taxonomic of of Therefore, a assessment only 2017). the barriers, of func- if al., to geographic portions become overlooked et as the community Mateo be such in a whether differ may 2013; circumstances obstruct may which Many may functionally but conditions saturated, 2014). note environmental example, species tionally al., harsh to for of (Vill´eger and et number ability, is, important occupied community dispersal same is is poor a the It have whether that can mask 2020). space communities may functional Mandrak, two richness & is, species similarity that in (Campbell the functional saturated, species) (i.e., for high) native redundancy accounting redundant historically functional only functionally high being Pool that (i.e., exhibits differentiation communities roles 2006; species functional of functional Rooney, the similar pool by & between original with accompanied (Olden the species be if locations unique community may ro- of geographical each homogenization loss functional new taxonomic the in similar into to contrast, increase fill traits due In an species of 2012). (i.e., introduced redundancy Olden, differentiation when & ecological taxonomic homogenized as homo- exhibit functionally such functional times, that les, be but six assemblages actually differentiation, found homogenization of can taxonomic (2014) showed dissimilarity) species pair communities al. exceeded a & Vill´eger paired et Furthermore, Europe (Pool instance, the genization. in For of disturbances fishes 2020). 40% anthropogenic freshwater approximately Mandrak, under of and & diversity homogenization not Campbell Gi- functional may taxonomic 2014; diversity 2001). that of al., functional (Tilman, Vill´eger et patterns traits, function 2012; the ecosystem species functions. Olden, and among with ecological redundancy composition their coincide and/or influences in tra 2 Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. a oAgs.Teuln edae tem nti raaehgl ope n bnat hs streams these abundant, and from complex occurs highly rainfall are the area of this 60% in than streams more headwater which upland of from The mm/year, August. 1,900 ranges to approximately temperature May of characterized mean air is a Annual area m; with this distributions. mm/year, 1,841 climate, precipitation m; monsoon and 1,342 subtropical the of –2.1 temperature of elevations seasonal Jiuhua influence highest the the asymmetric of to the by mainly Due with respectively. composed Mountain, m, are 1,787 China, Tianmu Province, and and Anhui Mountain, of south Huangshan the Mountain, at locating Mountains, Wannan The area Study 2.1 METHODS dams the AND abundance-based low-head MATERIALS or whether to incidence-based 2. on responses examine depend their similarities (1) above in to the differ in aimed changes similarities the data. We assemblage whether respectively. assess fish to data, of (2) functional and metrics and abundance taxonomic functional and including examined and differentiation, incidence we taxonomic collected China, or on data Mountains, homogenization Wannan based the faunal the fish on similarities in dams affect 1957) based low-head dams Strahler, study, blew segments low-head order, present free-flowing how (stream reference the scale streams 53 In regional first-order and the the dams 2006). low-head within at Rooney, by time created & over impoundments Olden homogenization 53 from 1999; biotic the induce weaken Lockwood, comparing will may & which species by community, (McKinney endemic communities at local replacing surveyed fish (2021) each species dam exotic/non-native al. of local low-head widespread et uniqueness each on the Li for However, 2019). affected segment scale. free-flowing al., local dams and et the low-head impoundment Liu the which 2015; between species) al., to assemblages lotic et pairwise degree (i.e., (Chu species the species) endemic lentic/sedentary investigated of (i.e., loss recently invaders the native second, cause in may and gain dams and low-head dams, remain with fish low-head gaps associated in modification to knowledge processes Habitat differentiation important responses or two their homogenization the least in underlying At mechanisms differ assemblages. the 2019). similarities affect and al., assemblage dams taxonomic low-head et the fish how whether Liu of First, received 2017; dams. metrics can have low-head al., dams functional dams by low-head making et driven larger whether homogenization/differentiation “low-head dams, Bu as now, biotic by Until effect see large regarding al., 2016). death ecological (but outnumber al., et watershed: same et attention widely Fencl small the Cooper less one dams with 2014; 2013; al., homogenization/differentiation in low-head al., et biotic dams Looy time, et promote (Van large (Yan local rivers same than natural alter decrease) the greater for and size dams” At potentially water, substrate impacts 2018). running ecosystems, cumulative and of al., river their slowing, place fragment et than flow in dams Hitchman assemblages 2021). low-head impoundments deepening, 2015; fish 2018, dams, create water al., on large fish, (i.e., et effects to of Li habitat similar movement localized 2013; However, upstream more al., 2015). the and irrigation, et al., constrain (Yan pronounced agricultural et areas less (Fencl consumption, upland have dams water in large often for streams dams headwater built that low-head the impacts often Individual human in 2012; are ubiquitous activities are al., and recreation dams height worldwide Low-head et and 2020). hydraulic ecosystems Vitule Colwyn, contribute a & aquatic 2007; may have Brewitt and degrade (Rahel, 2002; 2013) dams Hart, homogenization al., Low-head & et (Poff and 2015). Clavero structures changes species 2012; al., al., habitat of 2017). et dispersal et al., through patterns the (Vitule Daga et allowing range homogenization the Smith by natural barriers 2012; biotic to their physical Petrere, linked from outside to & constraints systems Petesse directly geographic into 2008; the are fish al., down of et which migration break (Johnson can and of part dams dispersal addition, most both the In the obstruct conditions, for Dams invasion habitat 2021). and modify al., in speciation et especially and problem, Couto environmental organisms 2020; primary Colwyn, a of 2021). become & al., habitat has (Brewitt et to diversity Couto due construction fish 2017; mainly on dam al., 2019), activities et al., human (Dias et of introductions (Reid influence world fish The non-native the and in alterations, fauna hydrological threatened degradation, most the among are fishes Freshwater ° Jnay o27.5 to (January) C ° Jl)wt h eno prxmtl 17.8 approximately of mean the with (July) C 3 < 5 n r yial vro rspillway or overflow typically are and 15m ° .Ana anali 1,100–2,500 is rainfall Annual C. Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. etdwdh() ae et m,cretvlct ms,dsovdoye m/) ae temperature water (mg/L), oxygen dissolved including (m/s), variables, velocity habitat seven current using (m), site depth sampling species, water ( each to (m), of field conditions the width than habitat in less wetted identified local was alive. were the if impoundment fishes characterized sites the We method, sampling when classification P, the sampled (2006) to (CWB-2000 was Nelson’s segment returned unit impoundment on free-flowing and and entire Based electrofishing counted, impoundment length. 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The each channel. along stream surveyed points the across ran that transects ° ) usrt orees n eeoeet.Tewte it a esrdaogtreeulyspaced equally three along measured was width wetted The heterogeneity. and coarseness, substrate C), RA eecluae o ahseis oass hte o-eddm nuebiotic induce dams low-head whether assess To species. each for calculated were ) > 5 m h enadsadr eito ftesubstrate the of deviation standard and mean The mm. 256 4 < FO 0adult 20 and ) Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. EMIPsoe hthbtthtrgniy(.. vrg itnet ein i o infiatydiffer significantly not did permutation like median) (ANOVA to types distance habitat average two ( (i.e., the conditions segments heterogeneity between habitat free-flowing habitat Im- that that and respectively. showed showed PERMANOVA variances, impoundments PERMDISP habitat and between 3). velocity the (Figure current differed of lower segments significantly and 19.18% free-flowing heterogeneity and substrate than and 28.98% coarseness depth, explained water substrate width, CAP water of higher had axes poundments second and first The conditions Habitat 3.1 “ the utilizing permutations 2018) RESULTS Team, 9,999 Core with 3. (R 2013). software test R al., Mantel in in et the respectively. performed changes (Oksanen were using package similarities, analyses between calculated ” All functional was relationships 1999). correlation White, and type the Pearson & data taxonomic (Nekola each investigated on of for we depending significance similarities similarities data), The assemblage abundance-based abundance-based pairwise and in changes incidence-based vs. of extent incidence-based functional the and (i.e., determine taxonomic to in changes addition, between In relationships the test to (taxonomic used similarity R was in test permutation performed “ Mantel were the differences The analyses utilizing the Statistical 2018) test segments. Team, to free-flowing Core Fur- (PERMANOVA) and (R variance 2013). impoundments software al., between of et habitat analysis (Heino local multivariate residuals in least-squares permutational group of their used permutations to (ANOVA) we via observations variance tested thermore, from was of het- distance significance analysis environmental the the Using the in and centroid, differences in segments. among-group free-flowing differences analysis compares the the permutational PERMDISP and the test F-statistics, the impoundments and functional), to both the 2003) 2006) between Willis, used vs. Anderson, erogeneity & we (PERMDISP; (taxonomic variables, Anderson dispersions environmental considered (CAP; multivariate standardized coordinates diversities of for principal of of distances types analysis Euclidean the canonical the between on in Based and differences the respectively. abundance-based) test to vs. used also based 2020). were al., t-tests et samples Daga Paired 2012; Olden, & Pool 2011; Lokweed, changes analysis, for taxonomic values the Positive for used approach (Fr.FS), Δ same (functional segments similarity the free-flowing functional Following the pairwise index. in in Bray-Curtis sampled each the were for assemblages to similarity and according (Im.FS) functional assemblages The data impoundment 2b). incidence the used (Figure We the type The segments). multiplying habitat CWM. by free-flowing the created and “ were in impoundments package data traits (i.e., the weight abundance-based for type with data habitat (CWM) abundance each first site and We for per above. values 2014) described trait al., approach of et same mean the community-weighted followed the we obtained differentiation, and homogenization functional For taxonomic incidence-based: (1) and follows: incidence as Fr.TS the segments, free-flowing on and based impoundments similarity type abundance-based ( and habitat incidence-based segments same taxonomic Both the 2a). (TS within (Figure respectively sites data, sampling Bray- abundance different the version, between quantitative assemblages differentiation, its and and homogenization taxonomic index For similarity Sørensen respectively. the index, using similarity data Curtis abundance and incidence CS sør sør sør n TS and Im.FS = 2 bnac-ae:taxonomic abundance-based: (2) ; Fr BC .Cagsi arietxnmcsmlrt (taxonomic similarity taxonomic pairwise in Changes ). sør epciey eecluae eaaeyfrteipudet ( impoundments the for separately calculated were respectively) , Δ Fr.FS – Sidct ooeiain hra eaievle niaedffrnito Bie & (Baiser differentiation indicate values negative whereas homogenization, indicate CS Δ Sadfunctional and CS sør 2 bnac-ae:Functional abundance-based: (2) ; Δ Δ Δ S o niec-ae n bnac-ae aa respectively. data, abundance-based and incidence-based for CS) CS vegan S eecluae sflos 1 niec-ae:functional incidence-based: (1) follows: as calculated were CS) BC site Im.TS = akg Osnne l,2013). al., et (Oksanen package ” 5 × site site species F × × BC =0.89, species trait site Δ arcswr rae eaaeyfrpairwise for separately created were matrices Fr.TS – Sbtentetoapoce (incidence- approaches two the between CS Δ × CS arcs(W)fricdnebsdand incidence-based for (CWM) matrices arxand matrix trait P BC > BC .5 n hto h impoundments the of that and 0.05) Δ Im.FS = arx(W)wscluae for calculated was (CWM) matrix S eecluae ewe the between calculated were CS) R Fgr 2a). (Figure 2 =0.13, species BC Fr.FS – Im P × Δ trait CS < n free-flowing and ) .0) However, 0.001). sør FD BC arxfreach for matrix Im.TS = Fgr 2b). (Figure (Lalibert´e” vegan sør – Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. epciey h omnseiswere > 6.04 species and common impoundments The in respectively. 5.94 both species was in richness [SD]) occurred species average deviation species the Twenty-nine dard which orders. of 5 segments, and free-flowing families and 11 impoundments representing collected, were species Thirty-one compositions Species 3.2 ± (2.31 < taenianalis parvus cocheilichthys I)(iue5,Tbe4.Hwvr 34%(=6)o arieasmlgssoe ieecsbetween differences showed assemblages pairwise of (n=461) 33.46% However, (quadrant differentiation showed 4). (n=566) Table taxonomic 41.07% 5a, and (Figure I) III) (quadrant homogenization presented assemblages taxonomic between (taxonomic changes (taxonomic similarity uniform similarity abundance-based in incidence-based changes the in tests: with (Mantel changes correlation similarity, positive significant taxonomic aspects a functional showed in in changes changes 2). the for (Table (taxonomic exhibited Regarding homogenization) was approaches abundance-based approaches two but abundance-based the differentiation between incidence-based using trend (i.e., those opposite an than and 21.89%), higher (taxonomic approach significantly incidence-based using was similarity taxonomic in homogenization/differentiation changes fish The of the patterns of type-dependent (Pearson’s Data values 3.4 coefficient correlation (Figure higher differentiation demonstrated (Pearson’s functional r approaches more of results pairs abundance-based slightly pairs our 51.09% for 48.91% were tests) approximately Specifically, Mantel the differentiation contrast, than In 3). taxonomic more Table 46.30%). of slightly similarity 4b, vs. cases were (53.70% taxonomic the homogenization homogenization functional assemblages, in taxonomic of pairwise changes of 1,378 cases between the the observed than all was Among correlation 4b). strong A (taxonomic 2). (Table homogenization (taxonomic similarity taxonomic 3). in Table ± changes 4a, the (Figure showed and homogenization cases assemblages 2.09% approaches, or than pairwise change abundance-based no frequent of using showed 51.67% more When pairs only were of However, differentiation 48.33% 38.03%). but taxonomic vs. differentiation, of functional (61.97% cases homogenization ( assemblages, taxonomic similarity pairwise of (functional functional 1,378 similarity in the functional changes assemblages Among the in fish exceeded changes of similarity with similarities taxonomic functional in and changes P taxonomic the and in (taxonomic 3.55%), changes differentiation both demonstrate to measures, similaritytended incidence functional on and taxonomic Based in changes between 1). Correlations (Table 3.3 segments free-flowing in occurred only whereas species) impoundments, in collected only ar rsne h poiecags(udatI)(iue5,Tbe4). (n=173) Table 5a, 12.56% (Figure and IV) (quadrant II), changes (quadrant opposite homogenization the presented abundance-based pairs but differentiation incidence-based 0) hc eeas bnac-oiat( abundance-dominant also were which 40%), 0) naddition, In 10%). 03)btencagsi entxnmcadfntoa iiaiy(iue4). (Figure similarity functional and taxonomic mean in changes between =0.34) .8[mean 1.08 < .7)( 1.37%) .0)(al ) hne ntxnmcsmlrt (taxonomic similarity taxonomic in Changes 2). (Table 0.001) ± ± .9[mean 1.09 18% a infiatyhge hntecagsi ucinlsmlrt (functional similarity functional in changes the than higher significantly was 21.89%) Δ n n nieosseis( species indigenous one and ) t Δ CS =-4.23, CS ± r =0.48, sør tnaddeviation]). standard BC n ucinlsmlrt (functional similarity functional and ) n taxonomic and tnpaygdnidella Ctenopharyngodon ± P , tnaddvain)wssihl ihrta hto h reflwn emns(2.11 segments free-flowing the of that than higher slightly was deviation]) standard P pycpi chinensis Aphyocypris < < .0) hra aooi ieetainwsacmaidb ekfunctional weak by accompanied was differentiation taxonomic whereas 0.001), .0;Fgr a.Aogte138piws sebae,6.4 n97 showed (n=917) 66.54% assemblages, pairwise 1,378 the Among 5a). Figure 0.001; Δ Δ CS CS ac platypus Zacco ncotm barbatula Onychostoma BC etbtaguilinensis Leptobotia sør mn hm prxmtl 09%(=8)pisshowed pairs (n=288) 20.90% approximately them, Among . and n taxonomic and RA , qaiu argentatus Squalidus irprosswinhonis Micropercops Δ > Δ 0) i aieivsv pce ( species invasive native Six 10%). CS CS 6 sør , sør ± coscelsfasciatus Acrossocheilus 41%+ 08% functional 20.82%; +- -4.14% : r Δ Mne tests: (Mantel ) .2seisi reflwn emnsprsample, per segments free-flowing in species 1.92 04)ta h niec-ae ns(Pearson’s ones incidence-based the than =0.45) CS Δ BC CS and eeas omnbtrr ( rare but common also were ) Mne tests: (Mantel ) BC aaiiae assimilis Parasinilabeo , fwih2.7 n31 fpairwise of (n=351) 25.47% which of , Δ rza sinensis Oryzias CS ie,ntv-naieseis were species) native-invasive (i.e., sør r eesgicnl correlated significantly were ) =0.34, Δ and , r CS =0.45, P sør iiec chuatsi Siniperca ± tngbu sp. Ctenogobius < and , Δ 41%+ 20.82%) +- -4.14% : Δ .8(mean 2.18 .0;Fgr 4a). Figure 0.001; CS P CS ie,indigenous (i.e., BC Δ < Acheilognathus FO sør CS .0;Figure 0.001; -2.09% : 02%+- -0.20% : < Δ BC t CS 10%; Δ Δ 0.21% : ± =-7.37, CS CS BC stan- , Sar- ( BC RA sør FO - : ± ) ) Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. ar hwddffrnito qarn I)(iue5,Tbe4.Hwvr 28%(=9)o pairwise of (n=590) 42.82% However, 4). Table 5b, functional (n=398) (Figure between 28.88% differences and III) showed I) (quadrant (quadrant assemblages homogenization differentiation presented showed assemblages and pairwise pairs incidence-based of functional (n=390) in between 28.30% changes changes which uniform between showed (n=788) correlation 57.18% significant assemblages, tests: a (Mantel showed changes similarity similarity abundance-based functional in Changes aincecetvle o aooi iiaiy(Pearson’s in similarity changes taxonomic with for correlations values ( coefficient positive addition, similarities lation In exhibited functional approaches differentiation. showed and abundance-based 42.82% taxonomic and with while variability, changes, incidence-based great uniform 4). showed the Table showing similarity 5b, both pairs functional (Figure assemblage in IV) of changes (quadrant 57.18% similarity, changes only taxonomic opposite in homogenization the changes abundance-based presented to pairs but Compared (n=276) differentiation 20.03% incidence-based and showed II), (quadrant pairs (n=314) 22.79% mately 00 n ml n eimsras(ike l,22) ntrso pce opsto,w on that found we al., composition, et species (Daga of species scale rare terms some intra-ecoregion In and segments, as free-flowing 2020). such the as al., and scales (such impoundments et this the small gained (Kirk both In (additive at streams in gains occurred 2016). medium studies species approaches, species al., twenty-nine and previous incidence-based et local small for with Socolar 2020), and differentiation agreement 2014; al., 2020) functional al., et in and differentiation et Kirk taxonomic are and (Villeger 2020; fish which homogenization processes) al., documented (subtractive faunal et et clearly loss fish Socolar we (Daga study, species of 2014; analysis local pattern al., of and the et scale processes) that (Villeger spatial species al., shown similarities the non-native between-community et have on widespread (Chu alter studies of depends may habitats establishment Previous the lentic species Furthermore, 2016). to endemic un- 2017). al., specific of species al., niches loss taking et of by new the Raab extirpation invasions of 2016; and fish the availability al., facilitate lotic in et the further of Liew result and and conversion 2015; can competition conditions the invaders environmental dams reduced example, native in For low-head of changes and/or advantage by 2019). drastic 2018). alien created al., withstand al., of impoundments et to Leit˜ao et able spread Dala-Corte in 2001; 2016; and habitats which Helfman, al., lentic occurrence 2019), & to et al., the (Scott T´oth favor et (Dala-Corte streams 2015; also upland compositions fish al., into may functional endemic et modifications and cause (Dorobek habitat may taxonomic extinguishing However, activities both local anthropogenic alters even with and further associated declining streams population upland species in homogenization absence habitat modifications the why increase Habitat explain study. could streams may of this dissimilarity which headwater basins in former impoundments, first-order observed different low in the not the four conditions within was habitat scales, from located in spatial were changes all finer surveyed common were at dams of dams Therefore, low-head these areas. 53 study, mountain this the in differentiation in that explain whereas Mountains Considering could characteristics, Wannan that environmental could the units 2003). of that across Poff, with heterogeneity differences range environmental environmental & consistent same greater greater (Olden are the in contain share result not results may would units scales Our did scales spatial spatial smaller heterogeneity segments. all Larger when free-flowing habitat (2019). in homogenization the 2021). differentiation al. local drive al., of habitat et the et that the Liu Li of that than and those 2015; segments, higher in suggested free-flowing al., slightly heterogeneity analyses and et was Fencl impoundments substrate current PERMDISP impoundments 2013; al., the and coarseness, and al., between et width, substrate differ et CAP Li (Yan significantly wetted decreased 2015; the studies significantly al., depth, other addition, et dams water with Fencl In consistent low-head increased 2013; is faster that and al., which and found oxygen et impoundments, (Yan upstream, we dissolved downstream impoundments study, and areas in habitats this velocity, plunging substrate local In the smaller modify in may flow, 2021). substrate dams slower larger low-head water, and streams, deeper flow headwater including in streams, disturbance in anthropogenic common a As DISCUSSION 4. 5). (Figure =0.27) .idella C. and .swinhonis M. P < .0,Pearson’s 0.001, n ot(uhas (such lost and ) r Δ =0.27, 7 CS sør r P n functional and r 04)ta ucinlsmlrt (Pearson’s similarity functional than =0.48) < > .0;Fgr b.Aogte138pairwise 1,378 the Among 5b). Figure 0.001; .guilinensis L. ) pcfial,w eetdhge corre- higher detected we Specifically, 0). Δ Δ CS CS and sør BC n functional and mn hm approxi- them, Among . .assimilis P. compared ) Δ CS BC of , r Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. pce) ag ubro h eann pce epcal o bnatseis fe edt eln or decline to tend often species) rare abundant (i.e., for gained (especially be species species could native-invasive assemblages remaining and al., fish the lost et local Fencl of species the 2013; number indigenous altered al., large of dams et a fraction low-head (Yan species), a which dams to Although large degree physicochemical weak. than capa- and and relatively habitats) storage extent hydrology lentic weaker the stream or Therefore, with on semilentic structures 2015). effects (i.e., of spillway significant impoundments less 60% or in have overflow than might factors typically (more dams small, low-head occurrence relatively individual of bility are frequency dams the low-head in As change was obvious homogenization an as functional showing (such of level the not species low increase roles abundance-dominant The redundancy) functional other 2012). (functional unique some Olden, endemic introduced roles & to functional some roles Pool the due similar 2006; functional that and with probably Rooney, unique & shown species with traits, (Olden rare species has despite abundance functional unique dominant in occur 2021) shared some unique can when and al., homogenization bring data, sharply et Functional abundance decline could (Li on redundancy. functional based conditions functional region taxonomies have the differentiation lotic this diverging potentially in taxonomic the in species exhibiting result endemic to research assemblages could and Previous adapted of abundance highly pair or 2012). a species range Olden, despite in & time, strategies non-random over (Pool The trait communities “losing” 3). of Table the and convergence 4b, for “winning” (Figure and changes differentiation approaches of similarity taxonomic abundance-based showed of selection assemblages using tendency fish homogenization of same functional trends overall the weak the showed indices, assemblages functional and of taxonomic pairs taxonomic between 66% observed approximately was Although correlation strong a as differentiation study, such this taxonomic species increase dominant in shared markedly result some auratus species example, Carassius can For rare which unique 2008). dominant), al., or et become stenosoma rarer (Cassey approaches species become abundance rare species on abundance in based dominant formerly shifts similarity shared (i.e., of the magnitude The abundance do, the abundances in on 2008). the depend al., but that changes change, et show not (Cassey will does approaches communities abundance between on different based species among index shared 2015). redundancy of al., number functional et the by Su If explained 2014; be changes al. lost, also similarity et are can in (Villeger traits indices discrepancy species similar functional This with and observed. species taxonomic is unshared differenti- differentiation between of taxonomic when functional gained, whereas, 14% but are occur; homogenization traits differentiation: will taxonomic similar functional homogenization with indices, functional but species functional but unshared homogenization ation and When homog- taxonomic taxonomic 3). functional assemblages; (Table the but assemblages) pairwise pairs differentiation pairwise for of (taxonomic 62% changes 24% outcomes approximately similarity func- contrasting Although enization: of presented than tendency pairs 3). higher same Table 38% was approximately the 4a, pairs) showed correlation (Figure 62% assemblages positive pairs) (approximately significantly of 52% assemblages taxonomic a and (approximately pairwise approaches, found differentiation of incidence also tional on number based we the than similarity combinations addition, lower functional with core and In markedly differentiation same taxonomic was the mean redundancy). differentiation share in functional may functional changes increase between species of (i.e., roles distinct level values functional the The trait that unique 2014). of suggesting with differentiation, al., taxonomic species et fish of Villeger introduced roles of that 2012; functional differentiation and similar Olden, compositional extinct with & the species become (Pool explain shared redundancy) when possibly shared differentiation functional occur may of habitat can (i.e., loss study slight differentiation the The this functional However, and in approaches. species assemblages. observed incidence rare on impoundments unique based the of differentiation in addition taxonomic in random result the as species Therefore, (such species impoundments. in rare as occurrence unique (such some species Meanwhile, uitous 1). (Table segments barbatula free-flowing of that with FO ). , erae nrltv bnac ls hn5 fthe of 5% than (less abundance relative in decreased ibgu styani Liobagrus and oii sinensis Cobitis amnnastenosoma Vanmanenia and , suoarstruncates Pseudobagrus nrae mr hn1%o the of 10% than (more increased oeta 0 fthe of 10% than more ; 8 esta 0 fthe of 10% than less ; RA Δ CS tngbu sp. Ctenogobius ,adsm nqerr pce uhas such species rare unique some and ), BC RA n functional and RA nipudet Tbe1.In 1). (Table impoundments in ) erae h rqec of frequency the decreased ) RA and nrae n ubiq- and increased ) Δ .fasciatus A. CS BC Onychostoma Fgr 4b). (Figure with ) V. Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. sas aial hnig(.. omryrr pce eoedmnn)(asye l,20) o instance, For is 2008). species al., community rare et other as (Cassey unique (such the dominant) a lost in become are when species species species unique occur rare rare the formerly will unique of (i.e., aspect some of abundance (Figure changing taxonomic the 20% radically approaches while and for also two community, aspects is differentiation the one taxonomic between perceived from the differentiation extirpated The of perceived locally 12% perceived of 4). of approximately Table patterns pattern that presented the 5, found extended of aspects can also further difference patterns functional we (2008) this study, the perceived greater al. of this the et the magnitude In are, Cassey the Therefore, abundances homogenization, differentiation. in the perceived over-dispersed differences on 2006). more Based observed Rooney, the the become. and & on traits, a (Olden species depend even in may trait functional traits), abundances differentiation driving rare biological and because be unique of homogenization homogenization to a perceived suites functional tends in only similar result shared is sharing may space composition differentiation species functional trait of the in numbers when differentiation Analogously, small different (i.e., segments. abundant free-flowing numerically in those with compared truncates two the between species common the instance, For differentiation 2008). ( taxonomic assemblages, al., in were across result et types abundance-dominant markedly are may (Cassey habitat identities species re- approaches species shared Our incidence-based rare the unique If approaches. for in taxonomic (2019). incidence-based differentiation of approaches small using al. degree a et the incidence-based similarity even Liu that taxonomic for with found consistent of we than study, are overestimation approaches this sults an In abundance-based indicating 2021). for 2), al., lower (Table et Li significant 2019; was al., differentiation et (Liu abundance in increase as bnac-ae ooeiain(ciny&L ot,20;Lue l,21) o ntne the instance, For 2019). al., et can as the dominant) Liu (such numerically of result 2007; the are species 15% may Sorte, whereas that shared identities La (i.e., ubiquitous, of species & communities and between abundance rare (McKinney dominant species homogenization unique become shared abundance-based in communi- of species cause differentiation abundance between shared small the functional shared the a in for commonly are when increase even pairs more differentiation species Therefore, 23% are incidence-based abundance-dominant and which species. in the communities, aspects rare Normally, across than taxonomic humans ties for homogenization. by pairs perceived perceived Table 21% of typically approximately 5, patterns found (Figure presented perceived we differentiation) including aspects instance, perceived incidence-based outcomes, For and and occur- contrasting homogenization) homogenization species 4). presented taxonomic abundance-based incidence-based whether pairs in but (i.e., same changes partial differentiation differentiation for the analyzed, incidence-based comparisons are are (i.e., major 2007; differentiation) data contrasting of Sorte, homogenization and directions abundance La in homogenization the & or result although (i.e., (McKinney rence study, can similarities similarities this which taxonomic functional In in perturbation, and 2008). changes after communities. al., for fish enough et approaches on Cassey drastically two dams the changes low-head between of will outcomes effects abundance the differentiation, of species and processes If homogenization ecological approaches fish exhaustive abundance-based structuring similarity reflects in the functional turn patterns that and in nuanced suggest which detect taxonomic ap- results could in incidence-based These sensitivity changes in to higher 4). between changes compared with (Figure correlation for addition, approaches strong approaches In abundance-based a two using 2). detected the (Table demonstrate differentiation results between misinterpreted to our functional trend be proaches, tended not exhibiting opposite traits should the despite similarity functional Therefore, approaches functional ubiquitously that simul- approaches. abundance-based some species found incidence-based as redundant using still for such functionally and we by debts and extirpation abundance, homogenization invasion abun- sharply to in and weak their declining less extinction markedly in roles of species increasing changes functional process of taneously unique experience extraordinary functions with which an ecological by of species al., to accompanied dominant et both Due was (Liu occur, equally loss versa. gain treated species vice species are instance, species and/or For rare loss dances. unique species and Normally, abundant shared 2019). the when indices abundance-based RA > 0) hrfr,teicdnebsdidcsoeetmt s aooi ieetainrltv to relative differentiation taxonomic fish overestimate indices incidence-based the Therefore, 20%). esta 0 fthe of 10% than less ; RA nrae,weessm nqerr pce sc as (such species rare unique some whereas increased, ) ac platypus Zacco RA and , erae nterfeuniso curne( occurrence of frequencies their in decreased ) .fasciatus A. tngbu sp. Ctenogobius .guilinensis L. and 9 ( FO and tngbu sp. Ctenogobius > .assimilis P. 0) hc eeas abundance-dominant also were which 60%), .barbatula O. esta %o the of 5% than less ; oeta 0 fthe of 60% than more ; FO , nimpoundments in ) .styani L. RA and , nthe in ) FO and P. Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. oh . oilt . 21) rdcigtohcgidadde vra rmfntoa ris Stati- traits: Le functional from A., overlap J. diet Tomasini, and M., guild J. trophic Culioli, Predicting L., (2011). Mercier, D., M., Mouillot, Mouchet, & Vill´eger, S., F., F., Loch, Guilhaumon, C., Albouy, Appendix in data fish about details RERERENCES more (For available are study this of findings S2). the support the to drafted used data and QL The QL tools. work. analysis laboratory and/or and/or reagents STATEMENT field AVAILABILITY DATA materials, the contributed conducted YY. RW YY from and and assistance LC YL with manuscript, data. QL, study. the the analyzed designed YY YZ and QL YY, interest. of CONTRIBUTIONS conflict AUTHOR no have we that declare We Committee. identifications. fish Ethic and Animal surveys INTEREST University field OF Normal of Anhui CONFLICT performance We the their 31872251, by (2016-84). in for Safety number: approved colleagues System Ecological all was (grant Research and to research Environment grateful Fishery China This Biotic are Anhui of of also Laboratory the we Foundation Key and for Provincial Anhui, Science Fund the from Natural Earmarked support the National the acknowledge and the 31372227) by and funded 31500452, was study the biotic This otherwise, structuring dams; in low-head traits contradictory. of function and or effects abundance ecosystem inaccurate ACKNOWLEDGEMENTS ecological be species of the may of maintenance assess conclusions role the fully quantitative the Given and to in 2003), qualitative identities. considered species Knapp, species be rare & than should Smith and homogenization rather 1999; dominant ranks al., the abundance the et when of (Walker species scales contributions in spatial differential small are differentiation). in assemblages the approaches abundance-based among abundance-based of but differences importance major homogenization the highlight homogenization) incidence-based further inclu- abundance-based results (i.e., outcomes, Our but contrasting differentiation presented differentiation perceived pairs incidence-based partial and (i.e., two aspects, the by homogenization between functional influenced perceived changes and debts ding invasion uniform taxonomic showed and both assemblages extinction for pairwise species approaches most of although functions homogenization Additionally, ecological fish dams. More similarity, the structuring low-head suggest functional dams. of in in results sensitivity because low-head changes higher differentiation our for of exhibited and detected study, approaches differentia- effects was abundance-based approaches this ecological and two that In the the homogenization suggesting between abundance-based overestimated China. trend fish and significantly opposite in incidence-based of an former both importantly, streams extent for the subtropical differentiation and whereas taxonomic in patterns fish approaches, dams facilitated the dams low-head which low-head by that in induced manner were the tion reveals the study of Our understanding approaches. our in abundance-based changes enhancing using of by for differentiation quantification important CONCLUSION and the particularly homogenization Therefore, be biotic species 2008). of those to al., of consequences prove et functions ecological yet (Cassey ecological may and communities abundance, similarity among species species community lost de- rare in may and changes formerly differentiation gained spatiotemporal perceived and The on were the homogenization part 2014). biotic to large of contribute al., in patterns may pend Vill´eger Perceived et which aspects. abundance-dominant, 2006; functional become of Rooney, roles differentiation & functional unique (Olden with similarity unshared functional affect can the as (such of dominant 10% become species than rare formerly and segments, free-flowing RA nipudet.Adtoal,cagsi ucinltat nrneo abundance or range in traits functional in changes Additionally, impoundments. in ) 10 .auratus C. and .sinensis C. more ; Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. aa .S,Odn .D,Gubiani, reservoirs. Neotropical D., in homogenization J. and faunal https://doi.org/10.1007/s10750-019-04145-5 fish species Olden, of introduced patterns S., of dependent roles V. the comparing Daga, reservoirs: Neotropical in Identifying assemblages vectors. fish their Gubiani, planning V., (2016). the strategic Abilhoa, via of A., O. fish A. dynamics migratory Padial, T. Sk´ora, Safeguarding F., S., (2021). V. Brenden, D. Daga, Brazil. J. & in Olden, hydropower & Z., small L., fishes. L. future M. modi- Messager, of on Wang, A., heavily B. dams E., T. in Couto, of K. Biodiversity Wehrly, effects M., large-scale (2013). https://doi.org/10.1016/j.ecolind.2015.10.016 D. quantifying N. Infante, and R, indicators F. reservoirs. A. 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All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. ae nSot&Hlmn(01 n i ta.(2019) al. et Liu and (2001) Helfman & Scott on ( based impoundments con- in dam cascaded collected Large-scale (2019). 1 X. China. TABLE Jiang, fish River, Lancang & Fisheries the the J., and in on Tao, Biology fauna J., dams fish Fish Hu, of low-head in differentiation L., phylogenetic of Chen, and taxonomic L., Influences drive Ding, structions (2013). C., F. Ding, China. C., Y. watershed, Zhang, ecosystem Chen, Qingyi & the and L., of https://doi.org/10.1007/s10641-012-0035-0 species. Chu, resilience, 495-506. streams 96, R., headwater diversity, minor Zhu, the attribute in H., and Wang, assemblages Plant dominant Z., Y. 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Indicators stream Er˝os, T., of & drivers B., vironmental Kern, Czegl´edi, I., T´oth, R., 7 02.https://doi.org/10.1016/j.ecolind.2013.10.006 10-20. 37, , https://doi.org/10.1016/j.ecolind.2019.01.063 742-748. 101, , pce opstos curneo rqec ( frequency of occurrence compositions, Species Order/Family/Species etbtaguilinensis Leptobotia anguillicaudatus Misgurnus rarus Cobitis sinensis Cobitis Cobitidae Cypriniformes hdu ocellatus Rhodeus nummifer Belligobio bidens Opasrrichthys fasciatus Acrossocheilus platypus Zacco Cyprinidae stenosoma Vanmanenia Homalopteridae lblEooyadBiogeography and Ecology Global Im 9 9-1.https://doi.org/10.1007/s11160-019-09580-0 895-916. 29, , n reflwn emns( segments free-flowing and ) rceig fteNtoa cdm fSciences of Academy National the of Proceedings 20 20 58 18.45 15.82 32.08 32.08 * 09 77 .25.39 9.62 37.74 50.94 * lblEooyadBiogeography and Ecology Global FO 77 39 66 16.61 4.94 Fr 16.66 24.06 33.96 3.77 Im 37.74 13.21 Fr Im 32 .779 5.37 2.54 7.93 17.31 3.77 4.80 40.91 20.33 11.32 14.60 13.21 32.41 62.26 11.32 86.79 67.92 6.70 94.34 75.47 35.85 15 (%) 3 7-8.https://doi.org/10.1111/geb.12141 574-584. 23, , FO .52.12 7.55 iest n Distributions and Diversity Fr ,adrltv bnac ( abundance relative and ), .*niae aieivsv s species fish native-invasive *indicates ). RA niomna ilg fFishes of Biology Environmental (%) Ecosystems 3 4016.htt- 1450-1460. 23, , 0,18003-18008. 108, , ,9-1.htt- 95-113. 2, , 8 111-120. 18, , RA ffishes of ) Ecological Ecological Reviews , Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. nprnhssaetenme fpiws assemblages pairwise of Values number respectively. approaches, the abundance are and parentheses incidence on in based assemblages pairwise for homogenization) 3 TABLE -2.09% -4.14% Diversity Abundance-based Incidence-based t-tests. samples paired type on Data based functional) taxonomic represent values vs. negative differentiation and (taxonomic functional homogenization, and functional considered and diversities taxonomic represent values of Positive types the between 2 TABLE umr fpretgso ( of percentages of Summary aito in Variation t Taxonomic iiec chuatsi Siniperca Percichthyidae sp. Ctenogobius Gobiidae swinhonis Micropercops potamophila Odontobutis Odontobutidae Perciformes sinensis Sinobdella Mastacembelidae albus Monopterus Synbranchidae Synbranchiformes sinensis Oryzias Adrianichthyidae Beloniformes truncates Pseudobagrus Bagridae styani Liobagrus Amblycipitidae Siluriformes assimilis Parasinilabeo idella Ctenopharyngodon barbatula Onychostoma taenianalis Acheilognathus parva Pseudorasbora argentatus Squalidus Parvus Sarcocheilichthys chinensis Aphyocypris rivulars Abbottina auratus Carassius oxycephalus Rhynchocypris chankaensis Acheilognathus Order/Family/Species =-3.49, Δ ± ± Sbtentetoapoce icdnebsdv.audnebsd and abundance-based) vs. (incidence-based approaches two the between CS P 18%0.21% -2.0% 21.89% 20.82% < Δ 0.001 S(mean CS .718 .61.75 5.06 1.89 3.77 * .937 .05.54 2.70 3.77 1.89 * 32 .642 1.37 4.24 5.66 13.21 * 69 32 28 3.37 12.87 13.21 16.98 * 13 .675 3.74 7.55 5.66 11.32 * Δ .31.244 1.85 4.46 11.32 9.43 * aooi n ( and taxonomic ) 07 .367 5.29 6.74 9.43 20.75 * .694 .110.46 4.91 9.43 5.66 * .356 .017.22 6.00 5.66 9.43 * .71.56 3.77 * ± .656 50 11.59 15.08 5.66 5.66 * .92.50 1.89 * 01 83 .67.70 9.66 28.30 30.19 * tnaddvain Functional deviation) standard .918 .53.85 3.85 1.89 1.89 * 60 92 71 19.83 27.14 79.25 66.04 3.42 6.10 6.06 16.98 4.28 20.75 11.32 4.10 7.55 2.50 7.55 1.89 17.91 25.22 17.79 18.86 13.21 5.66 9.43 5.66 FO 16 (%) Δ ucinlsmlrte ie ieetainand differentiation (i.e. similarities functional ) .71.64 3.77 t =-2.78, RA (%) ± ± 3.55% P 1.37% < Δ 0.01 S(mean CS ± tnaddeviation) standard t t =-4.23, =-7.37, P P < < 0.001 0.001 Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. niec-ae Taxonomic Incidence-based bnac-ae aooi ooeiain3.6 n49 44%(=9)4.0 (n=638) 46.30% pairwise of (n=524) number 38.03% the are parentheses change in taxonomic Total Values (n=199) respectively. 14.44% differentiation approaches, Functional assemblages abundance-based and homogenization based Functional (n=194) 4 14.08% TABLE (n=439) 31.86% homogenization Taxonomic (n=330) Abundance-based 23.95% trend Change homogenization Taxonomic Incidence-based type Data umr fpretgso hne ntxnmcadfntoa iiaiisfrbt incidence- both for similarities functional and taxonomic in changes of percentages of Summary aooi ieetain1.3 n25 44%(=7)5.0 (n=740) 53.70% (n=674) 48.91% (n=854) 61.97% (n=475) 34.47% (n=712) 51.67% (n=518) (n=704) 37.59% 51.09% (n=265) 19.23% change functional (n=666) Total 48.33% differentiation Taxonomic (n=336) 24.38% change functional Total differentiation Taxonomic change abundance-based Total differentiation Functional homogenization Functional change abundance-based Total differentiation Taxonomic homogenization hnetedAbundance-based trend Change 27%(=1)2.8 n38 16%(n=712) 51.67% (n=674) 48.91% (n=666) 48.33% (n=398) 28.88% (n=704) 51.09% (n=276) 20.03% (n=314) 22.79% (n=390) 28.30% homogenization (n=854) 61.97% (n=739) Functional 53.63% (n=524) 38.03% (n=566) 41.07% (n=639) 46.37% (n=173) 12.56% (n=288) 20.90% (n=351) 25.47% homogenization Taxonomic 17 differentiation Functional differentiation Taxonomic change incidence-based Total Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. sipudet iiaiy(mF)mnstesmlrt ffe-oigsget F.S aatdfrom 2020) al., (adapted et (Fr.FS) Daga segments 2012; free-flowing Olden, of & Pool similarity 2011; the Lokweed, minus (functional & (Im.FS) similarities Baiser functional similarity pairwise impoundments in as ( Changes impoundments (Fr.FS). habitat-type, segments free-flowing each for ( the created were ments similarity: data taxono- Functional abundance-based pairwise (b) in and (Fr.TS). Changes segments respectively. free-flowing data, of abundance and (taxonomic incidence similarities on mic based (TS) matrices ( similarity impoundments the i.e., similarity: habitat-type, Taxonomic each (a) similarity. Functional (b) 2 FIGURE dam, each at set were sites sampling Two study. segment this free-flowing downstream in and surveyed area dams impoundment low-head the the including of positions spatial 1 FIGURE Fr ,adcnetdit ucinlsmlrt arcs(S o h monmns(mF)and (Im.FS) impoundments the for (FS) matrices similarity functional into converted and ), rmwr umrzn h aaesadsaitclaaye o a aooi iiaiyand similarity Taxonomic (a) for analyses statistical and datasets the summarizing Framework apigdarmo h orbsn fWna onan,Cia lc pt ersn the represent spots Black China. Mountains, Wannan of basins four the of diagram Sampling Δ S eemaue sipudet iiaiy(mT)mnstesimilarity the minus (Im.TS) similarity impoundments as measured were CS) Im n reflwn emns( segments free-flowing and ) 18 site × species site × traits arcswr rae eaaeyfor separately created were matrices Fr ,adcnetdit taxonomic into converted and ), arcs(W)frincidence- for (CWM) matrices Im n reflwn seg- free-flowing and ) Δ S eemeasured were CS) Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. n ucinlcag ffihasmlgs I rtqarn,(I eodqarn,(I)tidqarn,and quadrant, third (III) quadrant, taxonomic second of (II) combination quadrant, different first a quadrant (I) represents fourth ( assemblages: quadrant (IV) fish correlation Each the of quadrant. Pearson change indicate each functional circles The in and Black provided are assemblages. respectively. tests pairwise similarity, Mantel 1,378 abundance-based from (b) and results similarity incidence-based (a) 4 FIGURE repre- velocity circle current gray and Black respectively. temperature; segments. segments, water free-flowing free-flowing and and impoundments impoundments between sent conditions habitat on based 3 FIGURE orltosbtencagsi aooi n ucinlsmlrte ffihasmlgsfor assemblages fish of similarities functional and taxonomic in changes between Correlations riainpo fteCnnclAayi fPicplCodnts(A)o apigsites sampling of (CAP) Coordinates Principal of Analysis Canonical the of plot Ordination SH usrt heterogeneity; substrate , SC 19 usrt coarseness; substrate , WW etdwidth; wetted , r n infiac ( significance and ) DO WD isle oxygen; dissolved , ae depth; water , P au)o the of value) WT CV , , Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. et r rvddi ahqarn.Ec udatrpeet ieetcmiaino aooi and (IV) taxonomic and of quadrant, third combination (III) different quadrant, a second (II) represents quadrant, quadrant first quadrant (I) Each fourth assemblages: ( fish quadrant. results of correlation each change the Pearson functional in indicate The provided circles Black are assemblages. respectively. tests similarity, pairwise functional 1,378 in changes from (b) and similarity taxonomic 5 FIGURE orltosbtenteicdnebsdadaudnebsdapoce o a hne in changes (a) for approaches abundance-based and incidence-based the between Correlations 20 r n infiac ( significance and ) P au)o h Mantel the of value) Posted on Authorea 6 Jul 2021 — The copyright holder is the author/funder. All rights reserved. No reuse without permission. — https://doi.org/10.22541/au.162561490.01268764/v1 — This a preprint and has not been peer reviewed. Data may be preliminary. 21