The first list of the rare grasshoppers of the Baraba and Kulunda steppes is presented. Two sets of distribution data are compared: (1) for the first half of 20^th century and (2) for 1972–2019. A series of digital maps was generated by MapInfo 12.03. The distribution patterns of several species, namely Asiotmethis muricatus (Pallas), Notostaurus albicornis (Eversmann), Eremippus simplex (Eversmann), Myrmeleotettix antennatus (Fieber), Gomphocerippus rufus (Linnaeus), Mesasippus arenosus (Bey-Bienko), Mecostethus parapleurus (Hagenbach), Locusta migratoria Linnaeus, did not change significantly. Four taxa (Asiotmethis jubatus (Uvarov), Arcyptera fusca (Pallas), Stenobothrus carbonarius (Eversmann), Sphingonotus coerulipes Uvarov) were relatively often in the first half of 20^th century and nowadays they are extremely rare. Two species, namely Megaulacobothrus aethalinus (Zubovsky) and Aeropedellus variegatus (Fischer de Waldheim), were recently found near the south-eastern and north-eastern boundaries of the region respectively. There are also the type localities of Asiotmethis jubatus and Mesasippus arenosus in the Kulunda steppe.

Acrididae, Caelifera, East Kazakhstan, Migratory locust, Pamphagidae, Russia

Grasshoppers (Acridoidea) are well known as possible pests, especially in agricultural areas. However, this superfamily includes a lot of endemic and rare species deserving conservation measures, particularly in mountains of the Palaearctic region (Uvarov 1928; Sergeev 1992, 1998, 2010; Lockwood, Sergeev 2000). More than 450 grasshopper species are included in the IUCN Red List of Threatened Species (IUCN 2020) and many are on regional Red Lists/Books. In grassland regions of Eurasia and North America, some dense and extensive populations of grasshoppers may be observed, especially during outbreaks. This pattern is usually determined by high abundance of several widely distributed species. On the contrary, there are only a few endemics and some implicit areas of acridid diversity (Sergeev 1996, 1997). These weak acridid foci of diversity often coincide or overlap the areas of locust and grasshopper upsurges (Sergeev 1996, 1998). As a result, some serious problems related to population management of both common and rare species may arise.

The south-eastern part of West Siberian Plain is the territory where numerous outbreaks of locusts and grasshoppers' populations have been developed and where some rare acridid species occur. Besides, this territory has been significantly transformed by human activity, especially in the beginning and in the middle of the 20^th century. Such regional and local transformations and/or also climate changes could and can result in some shifts in species and population distribution.

The first, but scarce data describing acridid diversity and distribution over the south-eastern part of West Siberian Plain were published in the 19^th century, but more or less comprehensive studies of local grasshoppers started only in the 1920s (Tarbinskij 1925; Wnukowskij 1926; Bey-Bienko 1930a, 1930b, 1930c). Almost all data for the first half of the 20^th century were analyzed and summarized by Berezhkov (1956). This allows us to compare changes in species distribution for the first half of the last century and for last several decades. The aim of this publication is to evaluate a general situation with rare acridid species in the Baraba and Kulunda steppes on West Siberian Plain.

Original data were collected from 1979 until 2019 in the so-called Baraba and Kulunda steppes. This huge area borders the Irtysh River to the west and south-west, the Ob River to the east, and the Altay Mts. to the south-east. Its northern boundary is approximately defined by the 56^th parallel north. Originally this territory was covered with grasslands (from meadows to dry steppes) and forests (mainly the birch and pine ones) (Isachenko 1985). However, the main part of the plains was transformed in agricultural lands (fields and pastures). Besides, there are some flood-plains with meadows and forest patches, solonchaks, and swamps.

The peculiarities of acridid ecological distribution were characterized by quantitative and qualitative samples collected in natural and transformed ecosystems, usually in the middle of summer when adults were dominated. Samples captured during a fixed period of time were made in every habitat investigated (Gause 1930; Sergeev 1986, 1992). Using this method, insects were caught with a standard net over a period of 10–30 minutes. Results for every habitat were recalculated for an hour. In many habitats, grasshopper densities were also counted on 25–100 arbitrarily placed plots 0.25 x 0.25 m (in some cases 0.5 x 0.5 m). After that the average density was estimated for every habitat investigated.

Some old materials, mainly from the field trips of Novosibirsk State University (1972–1977), were also used, but we tried to check and correct previous identifications. We used the Glonass/GPS navigators to determine geographical coordinates (see Appendix 1). For localities studied before 2000 we used Google Earth Pro (©Google, 2020) to get the same parameters. The main part of studied specimens is in the collections of Novosibirsk State University and the Institute of Systematics and Ecology of Animals (Novosibirsk). We obtained some data on general distribution of species from several main sources (Mistshenko 1972; Sergeev 1986, 1992; Latchininsky et al. 2002) and used the English names of several species published on the site "Grasshoppers of Europe" (2020).

We analyzed data from different sources for the first half of the 20^th century (Tarbinskij 1925; Wnukowskij 1926; Bey-Bienko 1930a, 1930b, 1930c; Berezhkov 1956 et al.) and indentified geographic coordinates of almost all localities. In 1972–2019 data were collected in 81 localities (Fig. 1). For some reasons these localities were investigated in quite different manners: (1) Some plots were studied during several years; (2) Some plots were explored during one warm season but at least several different habitats were studied; (3) The others (mainly the zonal ones) were investigated once and for relatively short time (from about half an hour to one hour). We considered some species which have been collected only in a few localities (less than 5 %, i. e. less than 5 localities) as rare forms for last several decades.

Maps of species distribution were produced on the basis of geographic coordinates with MapInfo 12.03.

Figure 1.

Localities: 1 – only one (mainly zonal) habitat were investigated once and for relatively short time; 2 – series of different habitats studied during one warm season; 3 – plots studied during several years.

In the Baraba and Kulunda steppes, the rare species of grasshoppers comprise about 24 % of local acridid fauna (14 species from 59) (Berezhkov 1956; Sergeev 1986). Two rare forms represent the family Pamphagidae and 12 species are from the family Acrididae. There are no endemic grasshopper species, but the ranges of two taxa are limited by the Kulunda steppe and the adjacent semi-deserts of East Kazakhstan (Asiotmethis jubatus and Mesasippus arenosus). The type localities of both species are in the Kulunda steppe.

The distribution patterns of several species, namely Asiotmethis muricatus, Notostaurus albicornis, Eremippus simplex, Myrmeleotettix antennatus, Gomphocerippus rufus, Mesasippus arenosus, Mecostethus parapleurus, Locusta migratoria, did not change significantly. Two species, namely Megaulacobothrus aethalinus and Aeropedellus variegatus, were recently found near the south-eastern and north-eastern boundaries of the region. Four taxa (Asiotmethis jubatus, Arcyptera fusca, Stenobothrus carbonarius, Sphingonotus coerulipes) were relatively often in the first half of 20^th century, but nowadays they are extremely rare. Some serious problems with the last species group may be explained by some destruction or transformation of many habitats during the Virgin Land campaign in the middle of the 20^th century when huge steppe areas have been ploughed and many steppe and meadow remains have become overgrazed. In any case, the local populations of almost all rare species are usually associated with a few types of habitats. This means that intensification and changes of human activity (inculding pest control during grasshopper and locust upsurges) may result in their elimination. A simple red-listing of rare grasshoppers is not enough in almost all cases, because nobody may control their populations. We should modify conservation strategy for grasshoppers, especially in the grasslands, with much more emphasis on conserving whole ecosystems and landscapes. As a result, pest management protocols should incorporate data concerning rare species populations and their habitats/ecosystems to avoid the extinction.

We wish to express our thanks to the late L.L. Mistshenko (St. Petersburg) and the late I.V. Stebaev (Novosibirsk) for their advices and cooperation and to all collectors of specimens. We are also indebted to all companions during our numerous field trips to the Baraba and Kulunda steppes. We also thank two anonymous reviewers for their valuable comments and suggestions.

These studies were financially supported by the joint programme of the Russian Foundation for Basic Researches and the Government of Novosibirsk Region (18-416-540001) and the Federal Fundamental Scientific Research Programme for 2013–2020 (No. АААА-А16-116121410123-1).

The authors have declared that no competing interests exist.