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Development of a quantification method for European brown hares (Lepus europaeus) in urban areas on the example of Lichtenberg, Berlin

Masterarbeit 2011 94 Seiten

Landschaftsnutzung und Naturschutz

Leseprobe

Content

1 Abstract

2 Introduction

3 European hares (Lepus europaeus)
3.1 Appearance, biology and behaviour
3.2 Abundance
3.3 Endangerment and status of protection
3.4 Actual methods for quantification

4 Preliminary investigations and preconditions for method development
4.1 Data set and object of investigation
4.2 Vehicle.
4.3 Light source
4.4 Illumination technique
4.5 Protocol
4.6 Security measures and timing of investigation

5 Data acquisition with the “Torchlight counting in urban areas”
5.1 Investigation areas / sample plots
5.1.1 Overview: district Lichtenberg
5.1.2 Friedrichsfelde (FF)
5.1.3 Herzberge (HB)
5.1.4 Weiße Taube / Fennpfuhl (WT/FP)
5.1.5 Falkenberg (FB)
5.1.6 Neu-Hohenschönhausen (NH)
5.2 Timing of investigations

6 Results of field work
6.1 Illumination area
6.2 Sightings of hares
6.3 Sightings of hares with regard to the habitat type
6.4 Other sightings

7 Discussion
7.1 Evaluation of the method with respect to objectivity, reliability and validity. 41 7.2 Interpretation of results
7.2.1 Selection of illumination areas
7.2.2 Calculation of the hare density.
7.2.3 Disruptive factors
7.3 Recommendations for a future application of the method
7.3.1 Vehicle.
7.3.2 Light source
7.3.3 Illumination technique
7.3.4 Protocol.
7.3.5 Timing.
7.3.6 Organisation

8 Conclusions.

9 References

Appendix

Index of tables

Tab. 1: Endangerment status of Leprs erropaers in Berlin, Brandenburg and Germany

Tab. 2: Technical data of LED LENSER® P7

Tab. 3: Category of illumination areas on the basis of the preparatory land use plan 22 Tab. 4: Tabular description of track FF.

Tab. 5: Tabular description of track HB

Tab. 6: Tabular description of track WT/FP

Tab. 7: Tabular description of track FB

Tab. 8: Tabular description of track NH

Tab. 9: Timing of countings (date, time and duration) on each track.

Tab. 10: Timetable of countings

Tab. 11: Overview of hare sightings with regard to the track

Tab. 12: Sightings and by-sightings made during 15 countings at different times.

Tab. 13: Influence of the migratory behaviour on the number of hares on each track

Tab. 14: Overview of quantification approaches

Index of figures

Fig. 1: European hare (Leprs erropaers)

Fig. 2: Distribution range map of Leprs erropaers

Fig. 3: Population density of Leprs erropaers in Germany, spring 2010

Fig. 4: Operating sheet: distribution of Leprs erropaers in Berlin

Fig. 5: Distribution of Leprs erropaers and Oryctolagrs crnicrlrs in Berlin

Fig. 6: Illumination areas for spotlight taxation and point transect counts

Fig. 7: Sights of hares in Lichtenberg 2006–2011

Fig. 8: Rabbit and hare

Fig. 9: Illumination technique of the torchlight counting in urban areas

Fig. 10: Preparatory land use plan of Lichtenberg with course of tracks

Fig. 11: Examples for habitat code W 2 – general residential building area

Fig. 12: Examples for habitat code g – green areas

Fig. 13: Examples for habitat code c – cemetary (all on track HB)

Fig. 14: Examples for habitat code a – agricultural area

Fig. 15: Examples for habitat code -f – fallows

Fig. 16: Land-use in Lichtenberg in ha

Fig. 17: Friedrichsfelde–overview of hare sightings and course of track

Fig. 18: Herzberge–overview of hare sightings and course of track

Fig. 19: Weiße Taube/Fennpfuhl–overview of hare sightings and course of track .

Fig. 20: Falkenberg–overview of hare sightings and course of track

Fig. 21: Neu-Hohenschönhausen–overview of hare sightings and course of track

Fig. 22: Illuminated areas and area proportion of habitat types for the five investigated tracks

Fig. 23: Area proportion of habitat types for the tracks HB, FF, NH and WT/FP

Fig. 24: Number of hares on each track of each counting

Fig. 25: Area proportion of habitat types (of all tracks) and their usage by hares

Fig. 26: Area proportion of habitat types of the "urban tracks" (without FB) and their usage by hares

Fig. 27: Plotsize and hares

Fig. 28: Organisation chart: regular hare monitoring in Lichtenberg

Fig. 29: Young hares close to a sidewalk end of August 2011

1 Abstract

The stock of the European brown hare (Leprs erropaers PALLAS, 1778 ) is declining since decades, in Germany as well as in other European countries. At the same time, the occurrence of European brown hares is a new phenomenon in urban areas. Hence, Lichtenberg, a city district of Berlin, the capital of Germany, even assumed a special responsibility for its new inhabitants.

Whereas a method for the quantification of this common game species in agricultural areas already exists, a new quantification method for city habitats is required in order to overcome several limitations. The aim of this master thesis is to deliver a suitable quantification method for Leprs erropaers, which can be applied by nature conserva- tion authorities in future.

By means of a strong LED torchlight and a bike, 153.74 ha of green area, which is usu- ally scattered between residential buildings, were investigated in the style of the previ- ous “spotlight taxation” [AHRENS et al. 1995, HOFFMANN 2003, SALZMANN-WANDELER 1974, WINCENTZ 2009]. These investigated areas belong to five different tracks. Each track was investigated three times in the late evening hours in the spring period from 8th of March until the 25th of April 2011. Within this time 37 sightings of hares have been made. Summing up the five maximum values from each of the 3 countings, one could assume that at least 17 hares live within the illuminated area. Considering the territorial behaviour, even a minimum number of 19 hares is probable. If additionally only suitable tracks are taken into account, a density of 16.98 hares/100 ha can be calculated – a surprisingly high value compared to the results of spotlight counting in surrounding fed- eral states, where the agricultural landscape, and therefore the natural habitat of Leprs erropaers, is more prevalent. However, a direct comparison to the hare densities in the open landscape, which are obtained by means of different methods is incorrect.

Nevertheless, if the proposed aspects for a future implementation will be taken into consideration in the long run, it is a realisable method for the quantification of urban hare populations. Moreover, the interested public can participate on this scientific approach as well. Then, cost reduction and the rising awareness for wild animals in the public are positive side-effects.

2 Introduction

In Germany, the stock of the European brown hare (Leprs erropaers PALLAS, 1778), a species that is classified as “threatened” in the present German Red List [SENSTADT 2005], has been declining since decades[FLUX & ANGERMANN 1990, KÖHLER 2008, LUNDSTRÖM-GILLIÉRON et al. 2003, MITCHELL-JONES et al. 1999, SMITH et al. 2005]. Also on

European level, a negative trend in the population development has been observed since the 1970s [HOFFMANN 2003]. BOYE [1996] even considers the species to be endangered.

The chief cause is the intensification of agriculture: over-fertilisation and a well-directed application of herbicides are responsible for a disappearance of wild herbs, the major forage for European brown hares. In order to raise the crop yield, farmland is merged together, and interjacent hedgerows and bushes dwindle away. Thus, the hares lose their food base as well as their coverage [PFISTER et al. 2002, SMITH et al. 2005]. SCHRÖPFER [1982] points out that especially large monocultures are derogatory to the stock of hares. In a mechanically cultivated landscape, Leprs erropaers needs fringe structures like hedgerows and stripes of wild herbs in order to bridge the hunger period after a harvest.

Not often observed, but all the more surprising for many experts was the immigration of

Leprs erropaers in urban areas during the last decade [KÖHLER 2008].

Stuttgart has, with 150 individuals on 87.4 ha, the largest intra-urban population of brown hares [WEIRAUCH 2010]. But also in Berlin, which is the city with the highest bio- diversity in Germany [STIFTUNG NATURSCHUTZ 2011], the hares have settled in the city, fol- lowing a range of other wild animals such as wild boars, raccoons, foxes and rabbits. Especially in the eastern parts of Berlin, in the urban districts Lichtenberg and Mar- zahn-Hellersdorf, sightings of hares have been made repeatedly.

Due to its local occurrence, the Senatsverwaltung für Stadtentwicklung Berlin[1] appoin- ted Leprs erropaers “Patentier”[2] of the district Lichtenberg. For the responsible Amt für Umwelt und Natur[3] this status justifies a special focus and extra expenses on the species. In order to initiate appropriate measures, it is important to have information about quantity and dynamics of the hare population.

A method for the quantification of Leprs erropaers in the open landscape already exists. Spotlight-countings by car[4] provide acceptable results, but the method is only suitable for taxation areas that are flat and poorly covered. It was, for example, applied in a quantification of hares in the Rosensteinpark in Stuttgart, where the hares live “like on a big green island” inside the city [WEIRAUCH 2010]. However, conditions suitable for spotlight taxations are rather an exception inside a city.

In contrast, a quantification of hares in other urban areas, for instance between resid- ential buildings, usually requires a strong modification to overcome several restrictions, particularly with regard to obstacles for the sight, obstacles for the car and the pre- sence of humans and their dogs, which may influence the behaviour of hares.

In the context of this master thesis, a method of quantifying European brown hares in urban areas has been developed and applied. In order to obtain long-term information about population dynamics, it is necessary to start with a regular quantification. Only the comparison of data from several years allows statements about the stability or alterations of the hare population and gives information about the necessity of mea- sures. Therefore, the aim is to set up a quantification programme for nature conserva- tion authorities that can be applied by volunteers.

In this regard the following questions will be answered:

1) Is the methob sritable to qrantify Leprs erropaers in rrban areas?
2) How can a regrlar monitoring be establisheb?Additionally, measures for an appropriate support of Leprs erropaers in Lichtenberg will be suggested.
3 European hares (Lepus europaeus)

This chapter will give an overview of the relevant aspects of the object of study – the European brown hare. These information as well as the knowledge about existing methods are the basis for the development of a new quantification method and further protection measures.

3.1 Appearance, biology and behaviour

illustration not visible in this excerpt

Fig. 1: European hare (Lepus europaeus)

[own drawing]

Leprs erropaers, the European brown hare, brown hare, European hare or Eastern jackrabbit, is a mammal belonging to the order of Lagomorpha and the family Lepor - idae. It is the largest hare in Western Europe. In its appearance it resembles the rabbit (Oryctolagrs crnicrlrs), which belongs to the same family, but to a different genus. Hares have, in comparison to rabbits, longer and stronger legs, longer and often erec- ted ears with black and white tips, a rather brindled fur, and with 3.5–5 kg, a higher bodyweight. The genus Leprs is characterised by its sprinting ability, nidifugous off- spring and the use of surface dens. Another obvious attribute of the hare[5] is its large body with 500–650 mm crown-rump length [NIETHAMMER & KRAPP 2003].

Hares are herbivorous, and their diet is selective and diversified. Cultivated crops play an important seasonal role. Investigations of stomach contents showed that they make up 95% of the hare’s food in wintertime. Wild herbs dominate the diet in the remaining time of the year [REICHLIN et al. 2006]. A distinctiveness of lagomorphs is the uptake of faeces from the caecum (coecotrophy). The coecotroph, which contains proteins, fatty acids and vitamins (above all vitamin K), is essential for survival – especially in habitats with a low availability of nutrients [HIRAKAWA 2001].

The European brown hare is a crepuscular and nocturnal animal which spends most of the daytime in its hiding place. The philopatric species has a homerange of 20–200 ha, depending on the environment [NIETHAMMER & KRAPP 2003].

Its reproduction period is from January to October [WILDTIERMANAGEMENT NIEDERSACHSEN 2011]. The mating season, which begins in March, is characterised by brisk chases. The European saying "as mad as a March hare" refers to that behaviour and became popular centuries ago: “In March, hares would conduct their courtship rituals. The males would leap and cavort to attract females’ attention. Then they would approach the female, who would “box” with them in an attempt to fight them off, before finally mating. Hares normally keep out of the way, so the sight of these leaping, cavorting, boxing hares led people to believe that hares went mad in March“ [SMITH 2011]. After 42 days of gestation, the doe gives birth to 2–3 (infrequently also 4–5) leverets. This regu- larly happens up to four times a year [NIETHAMMER & KRAPP 2003].

The German term for Leprs erropaers “Feldhase” refers to the fact that one can expect the animals on fields or open agricultural areas. Hares shaped their ecological and behavioural status during some million years[6] [NIETHAMMER & KRAPP 2003]. Urban areas occurred only during the last few centuries. Therefore, cities are a quite new and “strange” type of environment, characterised by the highest anthropogenic pressure. Nevertheless, Leprs erropaers is nowadays abundant in several German cities (besides Stuttgart mainly in cities of the former GDR: Cottbus, Dresden, Gera, Jena, Leipzig, Halle/Saale and Magdeburg) [KÖHLER 2008].

The terms that are linked to this phenomenon are described by LUNIAK [2009]: “Urbani- zation denotes changes in landscape (or a given habitat/environment) caused by urban development; Synanthropization means the coexistence of wild animal populations with humans and their existence in anthropogenic habitats”. The abundance of European brown hares in urban areas seems to be unusual, but is therefore a comprehensible consequence of changes in their natural environment.

According to LUNIAK [2009] it is not unusual that those synanthropic populations show several ecological and behavioural differences compared to conspecifics living in their native rural habitats. In particular, he mentions the following differences[7]:

1) a higher density of population connected with a reduction of individual (pair, family) territories,
2) reduced migratory behaviour,
3) prolonged circadian activity,
4) increased longevity (but worse health parameters),
5) changes in diet and foraging behaviour,
6) increased intraspecific aggression and
7) tameness toward humans and adaptations to human behaviour.

Whether all of these changes apply to Leprs erropaers or not, is not clear up to date. However, KÖHLER [2008] describes his own observations and confirms at least nos. 3 and 7 of the differences described by LUNIAK: The most conspicuous difference in the behaviour of the majority of urban hares is the reduced flight distance if a human approaches: Whereas hares of the open landscapes tend to flee immediately if they see a human in a distance of 30–40 m, the flight distance of “urban hares” is, with 5–20 m, considerably shorter. The preparedness to flee is observable by a slow increase of the distance between hare and human without getting into a rush. However, if a car appears and moves directly to the hare, it will trigger an immediate flight. The activities of the observed hares were monitored across the whole day, but preferably in the early morning hours. KÖHLER’S observation times were between 5:00 and 8:00 o’clock, before the majority of dogs and their keepers was about. Leprs erropaers is an adaptable species, as it not only copes with human abundance, but also to human structures: The species uses pavements, footpaths or streets to pass from one place to another, whereas sandboxes and playgrounds are used for sand-bathing.

Even though predators like fox (Vrlpes vrlpes), magpie (Pica pica) and hooded crow (Corvrs cornix) are abundant in higher numbers in the city than outside, they are not a high risk for the hares there due to a large alternative food supply. Foxes for example can find a broad range of easier prey, thus mainly dogs are after the hares [KÖHLER 2005].

3.2 Abundance

The European brown hare was widely spread in pre-glacial Eurasian steppe areas. Its habitat decreased due to the glaciation and the subsequent area-wide forest growth. In turn, forest clearings and agricultural activities in post-glacial times had increasing effects on the habitat of Leprs erropaers. Hence, the natural distribution range of the European brown hare is largely affected by human activities in landscapes [NIETHAMMER

& KRAPP 2003]. Fig. 2 shows the that the distribution pattern of Leprs erropaers nowadays also includes areas where the species has been introduced mainly as game species: New Zealand, parts of North America, South America, Australia, Scandinavia, Great Britain and according to the WILDTIERMANAGEMENT NIEDERSACHSEN [2011], also Ireland and South Siberia.

illustration not visible in this excerpt

Fig. 2: Distribution range map of Lepus europaeus

[Carlosblh, 2009]

In Germany, a comprehensive nationwide comparison of hare densities became pos- sible in 2001. Since this time spotlight taxations are carried out twice a year by WILD[8] and give detailed information about the size of the hare populations and possible changes. This project is actually based on the area-wide monitoring concept of the independent Wildtierkataster Schleswig Holstein, which was established in 1995 [SCHMÜSER, personal communication].

Fig. 3 shows the results of spotlight taxations in spring 2010: The density of hares in Western Germany is significantly higher than in the eastern parts of the country. Men- tionable at least for former countings is a high density of hares on some agricultural sites despite their intensive usage [LANDESJAGDVERBAND BAYERN E.V. 2009].

The lower number of hares in the former GDR might be caused by a structural change of the agriculture after the political change in 1989. First and foremost, the reduction of crop species caused a loss of diversity and a depletion of hare biotopes [STRAUSS & POHLMEYER 2001].

According to NIETHAMMER & KRAPP [2003], the average density of hares in spring varies between 20 and 30 individuals/100 ha. Under optimal environmental conditions, densit- ies of more than 100 individuals/100 ha may occur; however, populations with a density of less than 1 individual/100 ha can still be viable.

illustration not visible in this excerpt

Fig. 3: Population density of Lepus europaeus in Germany, spring 2010

[Composed on the basis of maps of WILD 2010, SCHMÜSER and SCHUNGEL, personal communi- cation; modified by SCHULZE]

The city state of Berlin also contributes to WILD with two taxation areas (in total 163.5 ha) which are located in the rural outskirts of Berlin (Fig. 4). In spring 2010, 16.8 hares/ha have been recorded [JANITZA, personal communication].

According to the information of the district foresters, Leprs erropaers is abundant in all forests of Western Berlin, but an area-wide occurrence has only been reported for the districts Spandau, Hermsdorf (including Frohnau) und Dreilinden. Outside of the forests, but within the city, the brown hare occurs in remaining open country areas, e.g in the former sewage fields of Gatow. In the eastern parts of Berlin, its abundance seems to be higher and area-wide in all forests, acres, industrial wastelands and ruderal/fallow lands, parks and even in residential quarters [EHLERT, personal commu- nication]

illustration not visible in this excerpt

Fig. 4: Operating sheet: distribution of Lepus europaeus in Berlin

[EHLERT, personal communication; modified by SCHULZE]

KÖHLER [2008] points out that the western part of the city is rather dominated by rabbits, whereas the eastern part is dominated by hares. Moreover, the following picture illus- trates that from all city districts Lichtenberg has, beside Marzahn-Hellersdorf, the highest abundance of hares in residential areas.

illustration not visible in this excerpt

Fig. 5: Distribution of Lepus europaeus and Oryctolagus cuniculus in Berlin

[Köhler 2008]

This unequal distribution within the city might be connected with the history of the divided Berlin. In general, the manner of housing constructions within a city is diverse by nature. The high population density in the city centre, the actual urban area, has only little space for green areas and green corridors between them. Due to the spatial limitation inside the Berlin wall (1961–1989), residential areas were built rather narrow, and the construction of the city autobahn led to a stronger dissection than in former East Berlin.

Therefore, the construction of housing estates in the periphery during the 1960s took place in mostly optimal habitats for brown hares. As a result, the animals adapted to human proximity and continued their migration from there towards urban sub-districts like Friedrichsfelde. The open spaces between those housing estates have not been fertilised since decades and thus provide a multifarious, forb-rich and continuous food supply. These green areas also offer a free sight, which allows the hares a fast flight to numerous hiding places [KÖHLER 2008].

3.3 Endangerment and status of protection

Leprs erropaers does not enjoy any legal protection (“gesetzlicher Schutz” GS), because the species is not listed in Annex IV of the Habitats Directive [EUROPEAN COMMISSION 1992]. Nevertheless, the species is mentioned in the Red List[9] of mammals of Berlin (BE), Brandenburg (BB) and Germany (D) (cf. Tab.1).

Tab. 1: Endangerment status of Lepus europaeus in Berlin, Brandenburg and Germany

illustration not visible in this excerpt

Even though Leprs erropears is classified as “endangered” in Berlin and Germany and even “critically endangered” in Brandenburg, it is considered a species of “least concern” (“LC”) on a worldwide scale [IUCN RED LIST 2011]. Moreover, brown hares come under the game law [SENSTADT 2007]. In most hunting grounds, however, they are only hunted on one day in November/December during hunting season [DJV 2009].

The reasons for endangerment in this country are on the one hand an irreversible de- struction of habitats, e.g. due to residential and commercial development, on the other hand the intensification of agriculture:

- intensive cattle grazing (conversion of meadows into pastures, accompanied with fertilisation and multiple mowing),
- intensive cattle crazing on poor grasslands,
- intensive farming (with regular fertilisation, intensive soil treatment and use of herbicides) and
- modern purification of seeds (which eliminates the spread of seeds of wild herbs).

A study within 12 European countries confirms that the primary cause for the decline of hare population is the intensification of agriculture, whereas field size, temperature, precipitation and hunting has no effect on the density throughout Europe [SMITH et al. 2005].

3.4 Actual methods for quantification

The determination of wild game populations is an important, but also a challenging task. Information about population dynamics or about the influence of certain factors on the development of populations require a quantification, which should be as exact as possible but still at appropriate costs [AHRENS et al. 1995]. The cost-efficient comparison of hunting bag statistics provides only information about the relative abundance of animals.

Visual counts, in contrast, are the simplest and oldest method to get information on absolute animal numbers or densities, but a major intrinsic problem is that the method tacitly assumes that all individuals are spotted, which may not be the case [WINCENTZ 2009]. Nevertheless, due to a good practicability, appropriate costs and reliable results, spotlight counting became the most common method to quantify Leprs erropaers [HOFFMANN 2003]. It is a statistical sampling method, which is suitable for flat agricultural areas that are poor in coverage. The population density of hares within an area of known size is assessed and extrapolated for a larger area.

Due to the fact that hares are crepuscular and nocturnal animals (except during the mating period), the counts take place by night. The first step is the determination of the investigation area. It is important to take all characteristic structures (different crops) into account. The track should be chosen so that it typifies the entire area. From a slowly driving (20 to 25 km/h) all-terrain vehicle with an additional spotlight at the side, a determined area is illuminated [AHRENS et al. 1995]. A suitable spotlight with a range of 150 m, which can be fixed perpendicular to the driving direction, is described by PEGEL [1986]. While one person drives the car, a second person counts the hares or their reflecting eyes, respectively. A third person takes the minutes (Fig. 5a). This kind of spotlight taxation is a so-called line taxation because the car follows a street (line), and data are obtained continuously [NATURSCHUTZPLANUNG.DE 2011].

First experiences with spotlight counting were made in the 1970s in Switzerland [SALZMANN-WANDELER 1974]. Today the method is used by WILD, the wild game research project of Germany [WILD 2009]. A modified method for distance sampling in only par- tially visible habitats, developed in order to include rural areas where the usual method could not be applied, has been described by WINCENTZ [2009] (Fig. 6c). This Danish method is an adaptation to areas with strong line-of-sight obstructions. In those land- scapes one has to define point transects. The distances between the transects are covered by car. The car stops at a predefined point, and the researcher illuminates the area all around. The visible areas are described as transects. This approach conforms to the point-stop-method [NATURSCHUTZPLANUNG.DE 2011]. In regard to the total illuminated

area, “point transect counts” are a less efficient method compared to the spotlight counting which is carried out as a line taxation (cf. Figs. 6b and 6c). Thus, spotlight tax- ation can either be carried out as a line taxation, as it is applied by WILD, or using point transects, as in the modified method by WINCENTZ [2009].

illustration not visible in this excerpt

Fig. 6: Illumination areas for spotlight taxation and point transect counts

a) schematic depiction of spotlight counting [AHRENS et al. 1995]
b) counting area Berlin-Blankenfelde covered by WILD [JANITZA 2011, personal communication]
c) point transects: visible subareas are indicated by yellow color [WINCENTZ 2009]

Detailed information about the implementation of the two counting approaches are spe- cified in Tab. 14, Section 8, where they are also compared to the “torchlight counting in urban areas”, a new variant of spotlight counting, which will be presented in the follow- ing sections. HACKLÄNDER, STUBBE and KÖHLER [personal communication] confirm that there is no method so far that is suitable for an implementation in urban areas.

4 Preliminary investigations and preconditions for method development

The spotlight counting described in the previous chapter is not suitable for urban areas, which have in general many line-of-sight obstacles. In order to develop a feasible, but also reliable method for urban environments, reasonable adaptations to urban condi- tions are necessary. This chapter contains considerations about the choice of the light source, the vehicle and the location of illumination areas.

4.1 Data set and object of investigation

Since 2006 the Amt für Umwelt und Natur in Lichtenberg has been collecting data about the hare abundance in the city, obtained on the basis of coincidental sightings by the public. The nature conservation authority gets support by the Umweltkontaktstelle[10], which requests interested people in Lichtenberg to report hare sightings (cf. Appendix and UMWELTKONTAKTSTELLE). Additionally, the Amt für Umwelt und Natur gets support by so-called “Naturschutzwächter”,[11] volunteers who give periodical reports on the state of flora and fauna within their area of responsibility.

One has to point out that the provided data are not systematic and therefore do not give any reliable quantitative information. An accumulation of dots, as it is observable in Fig. 7, is rather an indication of many people having seen (and reported) the same hare than the occurrence of one hare at one spot.

Nevertheless the civic participation raises valuable information about the occurrence of individuals as well as their individual behavioural characteristics. For example, the author of this thesis was invited by a cooperative retired couple to take pictures of “their hares – three large ones and a short one”, which they feed with carrots and seeds du- ring the winter months on a green area in front of their flat. In the first night, only the “short hare” occurred – and turned out to be a rabbit. A second attempt one week later gave the proof that there were also hares, but for some people it is not easy to distin- guish between the two species, especially when they show the same behaviour.

illustration not visible in this excerpt

Fig. 7: Sights of hares in Lichtenberg 2006–2011

[data: Database: UMNAT, generated with: MultiBaseCS Professional and PhotoshopCS, base- map: BKG 2006]

illustration not visible in this excerpt

Fig. 8: Rabbit and hare

a) The hare cowering in front of its food pile (at the top) looks similar to the rabbit (at the bot - tom);
b) rabbit (back) tries to defend its food pile;
c) and d) typical attributes of the hare (same animal as in the first pictures): long legs, dark ear tips;

[Photos: GERECHT 2011]

The Amt für Umwelt und Natur manages the data with the programme MultiBaseCS Professional, which also contains a GIS[12] -function and enables the creation of maps. Such a map indicates where in Lichtenberg it is likely to find hares and is therefore helpful for chosing the investigation area as well as possible sample plots.

4.2 Vehicle

The use of a car as it is practised with the spotlight counting is virtually not applicable in urban areas. It requires suitable roads and the compliance of traffic rules. In the city, there are barely any potential illumination areas accessible by car. The use of an elec- tric vehicle was temporarily taken into consideration, but its only temporal availability, its short cruising range limited by the scarcity of charging stations as well as depen- dence on suitable driveways rendered this alternative impossible. Eventually, an all-ter- rain bike turned out to be the best investigation vehicle as it is flexible in terms of the nearly unlimited accessibility, transportable by car (which is crucial if different investiga- tion areas are far away from the starting point – in this case from home, which is at the other end of the city) and low in costs. Additionally, it is quite inconspicuous – for pass- ers-by as well as for hares. The reduced flight distance of urbanised hares (cf. Section 3.1) inures to the benefit of the method.

4.3 Light source

The light source was chosen in view of the investigation vehicle. While the spotlight taxation allows the use of a lamp with power supply from the car, an independent light

source, a torch with a moderate size, is necessary for the use on a bike. In order to get a luminosity similar to the spotlight of a car (H4 55W 12 V [SCHMÜSER, personal commu- nication]) and a preferably long and extendible operating time, it is essential to use an LED torchlight with batteries. Additionally, the torch should be available at moderate costs. As a device that meets these requirements, the design model LED LENSER® P7 was chosen and used for the investigations. Another advantage of this torch model is the handlebar mounted detachable fixture, which is very handy in practice for the time the torch is not in use.

Tab. 2: Technical data of LED LENSER® P7

[Zweibrueder GmbH, personal communication]

illustration not visible in this excerpt

A disadvantage of the lamp is the continuously decreasing light intensity, wherefore the batteries have to be changed after a while[13]. In principle, it would be possible to create torches with a constant luminous intensity, but this was not the aim of the Zweibrüder company. WIRTH referred to the ongoing development of LED LENSER® torches and suggested the use of the successor model M7, which shows an enhanced ratio of light performance and energy consumption [WIRTH, personal communication].

Regarding the headlight range, pre-tests with the design model P7 showed that the contours of a hare-sized animal dummy are visible up to a distance of 100 m. This is important for the distinction between hares and similar animals with reflecting eyes.

As the application of a torch is a crucial difference to the spotlight counting, the light source gives the method its name: “torchlight counting in urban areas”.

4.4 Illumination technique

In view of the limited open area in the city, it is necessary to illuminate as much area as possible; however, the flight behaviour of the hares has to be taken into account as well. Furthermore, it is inevitable to stop the bike in order to prevent accidents and to pay attention to potential sightings. A plot, as depicted in Fig. 9, requires three different

positions for illuminating the greatest possible part of the area. Theoretically, the hare can be seen from position A, B and C. But if the investigating person enters the plot without stopping and illuminates from position A, the hare might be frightened off un- noticed. Therefore it is advisable to approach the plot gradually. For illuminating as much of the area as possible it is necessary to change the position within the plot.

Usually hares forage at sites where they have a circumferential view and can thus de- tect predators rather soon. Therefore, hares prefer open and clear sites during their nocturnal activity [NIETHAMMER & KRAPP 2003].

Hence, there is a high probability for an undisturbed hare to be in rather exposed posi- tion – a lucky chance for spotlight counting in general. A reduced flight distance of urb- anised hares may be a clear advantage for the method.

illustration not visible in this excerpt

Fig. 9: Illumination technique of the torchlight counting in urban areas

[own drawing, retroactively revised]

[...]


[1] Supreme nature conservation authority (Oberste Naturschutzbehörde)

[2] In the context of the Biotopverbund Berlin in 2006 [Senstadt 2006] Lichtenberg became ”Hasenpate“ (“Godfather of hares”).

[3] Lower nature conservation authority (Untere Naturschutzbehörde)

[4] Scheinwerfertaxierung

[5] To facilitate easier reading, the term „hare“ will be used synonymously for „ Leprs erropaers” and “European brown hare” in this thesis.

[6] Origin of Leprs erropaers: late Pliocene/ early pleistocene

[7] Luniak refers to birds and mammals in general. Therefore only differences that refer to mammals are listed here.

[8] WILD, the Wildtier Informationssystem der Länder Deutschlands, is a nation-wide monitoring programme of the Deutscher Jagdschutzverband (DJV, German hunting association) and its Landesjagdverbände (regional hunting associations).Since 2001 WILD is a permanent component of an ecological monitoring carried out with the aim to document game species populations as basis for the development of suitable strategies for their protection and for sustainable management. The Bavarian hunting association is not member of the DJV, but provides its data independently

[9] Even though the Red List of Threatened Species has no legal foundation and thus no legal relevance (in contrast e.g. to the Habitats Directive), it is like a condensed expert opinion and provides an important data base for the ecology-oriented planning [JESSEL 2002]. Red Lists are developed and published by administration departments of nature conservation [BFN, 2010]–in this case by the Senatsverwaltung für Stadtentwicklung.

[10] Environmental contact office: this is a drop-in centre for the public. It is a field of activity of the social service arm of the Protestant church in Germany.

[11] Nature conservation guards

[12] Geographic Information System

[13] This problem will be picked up again in the discussion.

Details

Seiten
94
Jahr
2011
ISBN (eBook)
9783656223511
ISBN (Buch)
9783656223726
Dateigröße
15.7 MB
Sprache
Englisch
Katalognummer
v196315
Institution / Hochschule
Christian-Albrechts-Universität Kiel – Institut für Natur- und Ressourcenschutz Abteilung Landschaftsökologie
Note
1,3
Schlagworte
European brown hares taxation Scheinwerfertaxierung quantification urban areas hare monitoring torchlight counting Feldhase small game Lepus europaeus Synurbanisation hares Lichtenberg Berlin

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Titel: Development of a quantification method for European brown hares (Lepus europaeus) in urban areas on the example of Lichtenberg, Berlin