Restoration of degraded drylands through exclosures enhancing woody species diversity and soil nutrients in the highlands of Tigray, northern Ethiopia Текст научной статьи по специальности «Биологические науки»

ОРИГИНАЛЬНЫЕ СТАТЬИ === RESEARCH ARTICLES ==

RESTORATION OF DEGRADED DRYLANDS THROUGH EXCLOSURES ENHANCING WOODY SPECIES DIVERSITY AND SOIL NUTRIENTS IN THE HIGHLANDS OF TIGRAY, NORTHERN ETHIOPIA

Kide M. Gebremedihin, Emiru Birhane*, Tewodros Tadesse, Hailemariam Gbrewahid

Mekelle University, Ethiopia *e-mail: [email protected], [email protected]

Received: 21.08.2017

Exclusion of grazing animals and tree plantations were among the methods used for the rehabilitation of degraded lands in tropical semiarid areas. Exclosures can foster secondary forest succession by improving soil conditions, attracting seed-dispersal agents and modifying microclimate for understory growth. This paper compares the woody species diversity and soil chemical properties under exclosure with increasing age and grazing land at different slope positions. The study has been conducted in northern Ethiopia from 12 exclosure sites paired each with adjacent grazing land with four treatments replicated three times. In the entire study 216 plots were examined of which 108 were in exclosures and 108 in communal grazing lands.There were four age classes and three slope positions in each of the landuses. Vegetation data were collected using plots measuring 100 m2. Soils for physicochemical properties were collected from the four corners and center of 5 x 5m plots which was inside the 10 x 10m plot. A total of 61 woody plant species belonging to 41 families were recorded. Diversity and species richness were higher in the exclosures than in grazing lands. Among exclosures these parameters were higher in exclosures older than 30 years and at the foot of the slope. Grazing lands, the youngest exclosures and upper elevation gradient recorded lower values. Chemical soil properties were significantly higher in the exclosures, among them in the oldest exclosures and at foot elevation (except for P) than these were in the grazing land, the youngest exclosures and upper parts of slopes respectively. Exclosures are instrumental to improve the woody species diversity and soil chemical properties in the drylands.

Key words: chemical soil properties, exclosure, slope position, woody diversity

Introduction tion of vegetation cover, soil and nutrient depletion in

Land degradation is a widespread problem Ethiopia (Haileslassie et al., 2005).

throughout sub-saharan Africa and its restoration is Forests and the benefits they provide in the form

a challenge for the management of many semi-arid of environmental protection, firewood, food and in-

areas (Yayneshet et al., 2009). Extensive deforesta- come have an important and critical role in enabling

tion and conversion of natural forests into agricultural to secure a stable and adequate food supply. Defor-

land is the main cause of land use change in Ethio- estation and land degradation, however, are reduc-

pia. The FAO (2007) estimated a deforestation rate of ing the capacity of forests and the land to improve

1410 km2 and the World Bank (2001) found 620 km2 environmental conditions and to provide other ben-

per year. The forest cover of the total area of Ethio- efits (Tadesse, 2001). Furthermore, land degradation

pia shrunk from 65% to 2.2% (Berry, 2003). 90% of exacerbates drought and desertification (Sonneveld

the total forest reduction was in the highlands, which & Keyzer, 2002). Soil erosion has accelerated on the

accounted 5.6% deforestation. These changes have Ethiopian highlands due to deforestation, cultivation

negatively affected the physical and chemical soil of marginal lands, uncontrolled grazing and higher

properties as well as the bioavailability of soil nutri- demand for fuelwood by the local communities (Re-

ents (Solomon et al., 2002). Moreover, the relative- using et al., 2000). This has led to a loss of the fertile

ly early and extensive deforestation in Ethiopia has top soil through erosion and nutrient depletion and

eroded the biological diversity to such an extent that resulted in a low plant diversity and agricultural pro-

some plants are faced with local extinction (Yirdaw, ductivity. Farmers can sustainably use their natural

2001). Land degradation affects the livelihood of the resources by introducing proper plant species on the

rural population and is a major threat to sustainable steep slopes and degraded areas to improve soil fertil-

land use (Hurni et al., 2005) by enhancing degrada- ity. Those species can be used as a source of forage

for livestock and pollen for bees. This would increase the flexibility in the management of land use, fodder and livestock hence enabling households to make a living and diversify sources of livelihood but also address land degradation (Mekonen & Tesfahunegn, 2011). An improved vegetation cover has assisted to increase soil cover thus decreasing losses of soil moisture through evapotranspiration. Better soil cover has also been vital in facilitating improved water infiltration while decreasing soil erosion and increased litter deposition and carbon sequestration that would upgrade fertility to increase productivity (Wairore et al., 2015). Although soil erosion is prevalent throughout Ethiopia, this problem is particularly severe in Tigray region, which urges the need to implement integrated soil and water conservation measures (Tadesse, 2001).

In response of the land degradation, the government of Ethiopia has initiated a number of projects including soil and water conservation works and establishment of exclosures (Nedessa et al., 2005). Ex-closures are areas closed off from the interference of human and domestic animals with the goal of promoting natural regeneration of plants and reducing land degradation of formerly degraded communal grazing lands (Seyoum et al., 2015). Exclosures are usually established in steep, eroded, and degraded areas that have been used for grazing in the past (Descheemaek-er et al., 2006). Priority areas for establishing exclosures are normally identified as a joint initiative of local communities and governmental and nongovernmental organisations (Descheemaeker et al., 2006). Exclosure is protecting the degraded land from tree cutting and free grazing of domestic animals (Men-gistu et al., 2005). In most cases, for establishing of an exclosure, this area should be abandoned as a result of being unsuitable for human and animal use (Nedessa et al., 2005). According to Lemenih & Kassa (2014) exclosure involves protecting areas mainly through social fencing from any form of cultivation, cutting trees and shrubs, or grazing by livestock. There are common management interventions in addition to protection that involves planting of seedlings (exotic or indigenous species), aerial seeding and construction of soil and water conservation structures to speed up succession through the modification of microcli-matic and soil conditions. As a result, diverse woody and non-woody plant species re-emerge, landscape greenness increases, soil erosion declines, sediment deposition downstream declines and water infiltration and stream discharge increase (Yami et al., 2006; Ba-bulo et al., 2008; Mekuria & Aynekulu, 2011).

Grazing impacts on soil properties depends on grazing intensity, with moderate grazing of 33 years

compared with an ungrazed control, higher values were found for pH, available P, and Mg in ungrazed sites compared to the grazed ones (Ajorlo et al., 2011). The concentrations of available P, total N, Ca, Mg, and K decreased after 1.5 years of heavy grazing compared with an ungrazed control in a tropical pasture (Ajorlo et al., 2011). In addition, heavy grazing resulted in lower water infiltration (Hiernaux et al., 1999) and higher soil loss (Tadesse & Penden, 2002) compared with moderately grazed sites. In Tunisia, Jeddi & Chaieb (2010) documented that 12-year exclosures enhance the total plant cover, dry matter yield, species richness, and contents of organic soil matter, total nitrogen and water infiltration rate compared with continually grazed area. Similarly, Cheng et al. (2011) indicated that 20-year exclusion of livestock grazing significantly increased aboveground and belowground biomass and species richness for five different communities compared with that before exclusion of livestock grazing in a typical steppe of the Loess plateau, northwest China. Additional case studies conducted on exclosures in the central and northern highlands of Ethiopia. So, it was discovered that exclosures had twice more plant species richness and diversity value as compared with communal grazing lands after 22 years of exclosure establishment (Mengistu et al., 2005). And the richness of13 woody species increased after 8 years of exclosure establishment (Birhane et al., 2006). Also, an increase in organic soil matter, total N and available P after 10 years of exclosure establishment was found (Mekuria et al., 2007). Finally, a considerable decrease in soil loss was reported after the establishment of exclosures in communal grazing lands (Descheemaeker et al., 2006; Girmay et al., 2009; Mekuria et al., 2009). Although there have been studies that compared the effect of exclosures on plant diversity and soil with adjacent open grazing lands, most of them are patchy and considering a single area. Studies on the effect of age of exclosures on plant diversity and soil property are few. Therefore this study provides information on the status of woody plant species diversity in 12 exclosures as compared with the adjacent grazing land in the highlands of Tigray, northern Ethiopia. This research was conducted to understand the role of exclosure in restoration of woody plant species diversity and soil chemical properties in two land use types with increasing age of exclosures at different slope gradients. This paper tries to address the following hypotheses: Availability of nutrients are not significantly different between exclosures and adjacent grazing land with increasing age of exclosure and elevation gradient; and: Woody species diversity is not significantly different between exclosures and

grazing land with increasing age of exclosure and elevation gradient.

Material and Methods

Description of the Study Area

The study was conducted in the highlands of Tigray region in four zones and four districts representing 12 exclosures and adjacent open grazing sites (Fig. 1). The distance between the exclosure and the adjacent grazing land was in the range of 50 to 100 m. The districts, namely Tahtay Maychew, Degua Temben, Atsibi Wen-berta and Enda Mehoni, were 273 km, 50 km, 71 and 129 km away from the capital city of the region, Mekelle respectively.

All sites have a tropical semi-arid climate. The altitude of the study sites ranged from 2232 to 2937 m a.s.l. (Table 1). The rainy season usually occurs between June and September (Fig. 2), the growing season varying between 90 and 120 days.

Soils of the study sites were classified into four major groups: Luvisols (Alfisols), Regosols (Enti-

sols), Cambisols (Inceptisols) and Calcisols (Aridis-ols) (WRB, 2006), but the sites were dominanted by Luvisols (Alfisols) and Cambisols (Inceptisols). The common woody vegetation species in exclosures and in adjacent grazing lands included Acacia etbaica Schweinf., Acacia seyal (Del.), Becium grandiflo-rum (Lam.) Pichi-Serm., Euclea racemosa subsp. schimperi (A. DC.) F. White and Maytenus arbuti-folia (Hochst. ex. A. Rich) Wilczek (Mekuria, 2010). The livelihood of the households in the study area was a mixed crop livestock farming system. Major land uses in the study area included cultivated lands (between 9 and 33% of the area), forest-lands (3% to 58%), exclosures (3% to16%), communal grazing lands (6% to 39%) and others (20% to 41%) (Mekuria, 2010). There were seven main cultivated crops namely Tef (Eragrostis teff (Zucc.) Trotter), Bread wheat (Triticum aestivum L.), Maize (Zea mays L.), Sorghum (Sorghum bicolor (L.) Moench ), Barly (Hordeum vulgare L.), Faba bean (Viciafaba L.) and Hanfets1. The major animal populations were cattle, goats, sheeps, donkeys, camels, mules and horses.

1 Hanfets is a popular mixture of wheat and barley grown in the highlands of Eritrea and Tigray (Northern Ethiopia).

Fig. 1. Location of the study sites in the highlands of Tigray, North Ethiopia.

Table 1. Specific study site age, altitude and geographic location

Specific site

Zone

District

Age(year) Altitude (m) Geographic location

Adihintaweinai

Halla

Melgim

Endagebriel

Gurzoemni

Mezewle

Adikolakul

Suhulkoma

Wereriba

Gratselim

Kerenadidemsash

Maibiati

East Atsbi wonberta <10 2201-2312

South east Degua Tembien <10 2232-2937

East Atsbi wonberta <10 2264-2343

East Atsbi wonberta 10-20 2248-2351

Central Tahtay Maichew 10-20 2244-2322

East Atsbi wonberta 10-20 2325-2411

South east Degua Tembien 20-30 2180-2214

East Atsbi wonberta 20-30 2295-2347

South east Doguetembien 20-30 2200-2358

South east Degua Tembien 30-40 2369-2458

South Endamekoni 30-40 2314-2419

South east Degua Tembien 30-40 2358-2429

39°038'60"-39°050'52" East 13°012'75"-14°04'41" North 38°030'17"-38°040'57" East 13°054'3"-14°020'30" North 39°038'60"-39°050'52" East 13°012'75"-14°04'41" North 39°038'60"-39°050'52" East 13°012'75"-14°04'41" North 38°030'17"-38°040'57" East 13°054'3"-14°020'30" North 39°038'60"-39°050'52" East 13°054'3"-14°020'30" North 38°030'17"-38°040'57" East 13°054'3"-14°020'30" North 39°038'60"-39°050'52" East 13°012'75"-14°04'41" North 13°016'23"-13°047'44'' East 39°03'17''-39°024'48''North 38°030'17"-38°040'57" East 13°054'3"-14°020'30" North 39°016'52"-39°035'31" East 12°038'4"-12°051'39" North 38°030'17"-38°040'57" East 13°054'3"-14°020'30" North

B. Central zone of Tigray/ Tabtay maychev

A. Sou rli eastern zone of Iigriy/Hgere sela.ni

hkMtlErfllK ym

.01 =^3 l.'ar АЭГ №f JJ1 Jul Ajg sen Ol mu Inj

Ш "-bntWyTofa Rainfal in mr

- ИжЛЫуДче-аде htaTen^:. п 'С

* llbr.ïLyA-'Kïî?.;-.?. 7 an in "С

=-

5 Months of ths year Jan FeB №г Арг Ш1 Ап Sep 0=1 Nc"' 1560

■ M Witts Vs Average Total Rain ta I in ran

- Hantfs Vs Aueirsge Het.Twp. in't

I— Mantis Vs Average Hin. Temp. in't

C. Southern zcm&T nd a me ho ni

i ЬвйЫу Ibl Ä Kjicitl in iOD

- lianedyAraegall*i.TançLÎn t

* МсчйЫу Jonago Юп.Топр_ in

s

И" 8

- 12 £ I

D. E astern zone of T igriy/ Astb i tî enb erta

Fig. 2. Monthly average temperature and rain fall of the study area (A, B, C and D) from 2002 to 2014 (EMA, 2014).

Exclosure is a method of rehabilitating land by protecting an area from the interference of animals and human encroachment for a limited period of time, depending on site capacity and vegetation re-establishment (Seyoum et al., 2015). The grazing lands are areas open for continuously grazing by livestock.The exclosures are mainly covered by trees, shrubs and the ground by grass. The life forms of woody plants in the exclosures were 35.1% trees and 39.73% were shrubs, while the rest (25.17%) were woody herbs and climbers. The life forms in the open grazing lands were 83.37% shrubs and 5.7% were trees, while the rest (10.93%) were woody herbs; shrubs significantly outnumbered the trees in the exclosures. The abundance of the naturally regenerated woody plants in the exclosures was 91.03% while 8.9% was found artificially planted but no planted seedling was observed in the open grazing lands. The abundant species in the exclosures were composed of naturally regenerated species.

Experimental layout and design

There were 12 exclosure sites having adjacent grazing land, divided into four age classes and three slope gradients to study the age, slope and land use effect on woody species diversity and chemical soil properties. The first age group had less than ten years old exclosures with triplicate sites (Halla, Meligim and Gidimihantaweynay), the second age group was 10 to 20 years old exclosures with triplicate sites (Gurzoemni, Mezewle and Endagebriel), and the third age group had 20 to 30 years old ex-closures with triplicate sites (Addikolakul, Wereriba and Shul-koma). The fourth group had more than 30 years old exclosures with triplicate sites (Maybe'ati, Wadrat and Endaarbaetuenssat).

The role of the exclosure on the soil fertility and the diversity of woody plant species were studied by taking soil and the identitiy of woody plant species and number of plants, under the different ages of paired exclosures and adjacent grazing lands. The experiment was composed of 12 experimental units with four treatments replicated three times. In the entire study 216 plots (12 x 3 small plots x 3 slope positions x 2 pair exclosures and adjacent grazing lands) were examined of which 108 were in exclosures and 108 in communal grazing lands. In each exclosure and grazing land randomly established three transects spaced at a minimum distance of 75 m (Fig. 3). The number of transects were based on vegetation density, spatial heterogeneity of vegetation, and area of the site. To avoid edge effects, the

first transect were laid 30-50 m inside the exclosures and grazing lands. Transects were parallel to each other and to the topography of the landscape. In each transect, three slope positions were delineated and a sampling plot measuring 10 x 10 m was established. In each plot, 5 x 5 m subplots for physical and chemical soil analysis were developed (Fig. 3). Each of the study sites were divided into 3 slope gradients: upper slope (US), middle slope (MS) and foot slope (FS). The US position is the uppermost portion of each study site and it can receive little or no overland flow but may contribute runoff to down slope areas. The MS position receives overland flow from the upper slope and contributes runoff to the FS. The FS represents the lowest part of each study site and receives overland flow from both mid and upper slopes.

Plant and soil sampling methods

Plant and soil samples were collected from October 2013 to January 2014 for a total of four months from four types of exclosures and adjacent surrounding grazed land. All woody plants were sampled for diversity in 10 x 10 m quadrates (100 m2) for trees and shrubs from both sites. The plants were identified in the field and verified using reference books such as Bekele-Tesemma (2007), Hedberg et al. (2003), Hedberg & Edwards (1989), and Edwards et al. (1995, 2000). All woody plants (trees and shrubs) found in each plot were counted. Each plant height, diameter at breast height (DBH), diameter at stump height (DSH) and plant number were recorded. The abundance (total number of woody species in a given area), density (number of individuals of a species in an area per ha) and frequency (number of times a species recorded in a given number of plots) of woody species were calculated.

Fig. 3. Experimental designs of the soil and vegetation sampling in one replicate of an exclosure with its paired communal grazing land.

Soil samples were collected from 5 x 5 m subplots nested within the 10 H 10 m at the centre of the main plots. A total of 216 soil samples were collected. The soil samples from each plot were taken from the four corners and the centre of a square plot at 50 cm soil depths following an «X» pattern of the main plot to form one composite sample in order to determine organic carbon, pH, EC, N K and P of the soil in exclo-sures and adjacent grazing lands. The five soil samples measured 300 g, each collected from 50 m depth in each 25 m2 plots, were mixed and form 1500 g in total and make a single composite sample to represent the sample plot. From the composite sample 1 kg soil was taken and put into plastic bags, secured, labeled and brought to the soil laboratory. Soil samples were analysed for pH and electrical conductivity on 1:2.5, soil: water suspension method. The organic matter was analysed using the Walkley-Black method (Van Ranst et al., 1999), the total nitrogen content by the Kjeldahl method (Bremmery & Mulvaney, 1982). The available potassium and texture were analysed with flame spectrophotometer and hydrometer method (Gee & Bauder, 1982). The available P was determined using the Olson method (Olsen & Sommers, 1982).

Statistical analyses

The number and abundance of the woody species diversity (Dominance (D), Shannon (H), Simpson (1-D), Evenness (EAH/S) with ages of the exclosures, adjacent grazing land and slope positions were analysed using the PAST software package, version 1.91. The differences in soil parameters between an exclosure and its adjacent communal grazing land at different age groups and landscape position were assessed using ANOVA with Tukey HSD test after checking normality test. Statistical package for social sciences (SPSS) version 20 was used to analyse the chemical soil properties.

Results and Discussion

Woody plant species composition in exclo-sures and grazing lands at different age and slope gradient

In total there were noted 61 woody plant species, representing 41 families, and 51% were trees and 49% were shrubs (Appendix 1). Among these plant species 8% were planted while the rest, 92% plants, were naturally grown. In the

exclosures there were 60 plant species and 40 plant families, of which 53% were trees and 47% shrubs, while the grazing land had 28 plant species that belongs to 21 plant families (Appendix 2 and 3). So, from the total species found in the study area 32 species were only found in exclosures. This study is in agreement with research done in exclosures and open grazing land in Tigray where 39 plants were found in both exclosures and open grazing land, of which 31 plants were naturally found and 8 were planted (Birhane, 2002). The same author found 27 plant species and 18 families in exclosures, of those 37% trees and 52% shrubs, but the open grazing land had 14 plant species of 12 families and 50% were either trees or shrubs. Another study found 56 woody trees and shrubs belonging to 28 families in both disturbed and undisturbed areas, the undisturbed areas had 47 woody species belonging to 26 families and 42 woody species belonging to 24 families in disturbed areas (Dejenie, 2011). The foot slope had 56 plants representing 39 families, 52% trees and 48% shrubs (Appendix 4), while the middle slope had 49 plant species of 32 families, 51% trees and 49% shrubs (Appendix 5). The upper slope had 42 plant species of 28 families; from those 48% were trees and 52% were shrubs (Appendix 6). Exclosures less than 10 years old had 18 plant species of 12 families, of which 67% were shrubs (Appendix 7), at the same time ex-closures with an age between 10 and 20 years old had 23 plant species representing 12 families and 57% were trees (Appendix 8), while ex-closures with an age between 20 and 30 years old had 36 plant species of 27 families and 53% were shrubs (Appendix 9). Exclosures older than 30 years had 49 plant species of 36 families, with 51% trees and 49% shrubs and had a higher species richness than in exclosures of the other three age groups (Appendix 10).

Woody plant species diversity in exclosures and grazing lands at different age and slope gradient

In the study area 61 plant species from 41 plant families were found, which is more than the result found in exclosures and open areas in eastern Tigray (Birhane, 2002). The exclosures had a higher diversity, high species richness and these were less evenly distributed, whereas grazing land had a low species richness and the species were evenly distributed (Table 2).

The plant density and abundance of plants were higher in exclosures and lower in grazing land (Appendix 2 and 3), which is in agreement with exclosures in eastern Tigray (Birhane, 2002). The exclosures in this study had a higher diversity than the exclosures in central and northern Ethiopian (Mengistu et al., 2005). Undisturbed sites have a higher diversity than disturbed sites in the Awash National Park in central Ethiopia (Molla et al., 2009). The establishment of exclosures improved the composition, density, richness, and diversity of woody species in comparison to open adjacent sites.

Woody species were substantially richer in exclosures than in open areas, indicating the importance of exclosures for the conservation of biological diversity (Mengistu et al., 2005). Diversity is the most widely used criterion to assess the conservation potential and ecological value of a site (Magurran, 2004). Moreover, it is an important element in resource management planning. This especially holds true for rare and endangered species (Jama & Zeila, 2005). Exclosures are supposed to contribute to the conservation of biological diversity. The higher Shannon diversity indices in the exclo-sures indicate a higher species diversity in the exclosures than in the open site (Getachew, 2014). The relatively high diversity values of exclosures compared with that of the open areas in turn indicates the importance of exclo-sure practices for the conservation of genetic resources of the woody species, particularly rare and unique species that are under heavy threat of extinction. Old age exclosures had a higher plants diversity, high species richness and these were also evenly distributed (Table 2), which is in line with Mekuria (2013), who indicated that the oldest exclosures had a higher diversity and species richness than the youngest exclosures.

There was a significant difference in plant diversity along the slope gradients (p < 0.05). The foot slope of the mountain had a high diversity and plants were evenly distributed. The diversity was higher for the foot slopes followed by the middle and upper slope. This result contradicts to Mekuria (2013), who found a higher diversity at the upper slope.

Woody plants frequency, abundance and density in exclosures and grazing lands at different age and slope gradient

In the study area Euclea racemosa L., May-tenus arbutifolia (Lam.) Exell, Becium grandi-florum (Lam.) Pic. Serm., Acacia seyal Delile and Juniperus procera Hochst. ex Endl. were the most frequently found, while Clutia lanceo-lata Forssk., Diplostigma canescens K. Schum., Justicia schimperiana (Hochst. ex Nees) T. Anderson, Morus alba L., Berberis holstii Engl. and Pittosporum viridiflorum Sims were found the least frequently. Individuals of species from the plant families Fabaceae, Celastraceae, Eb-enaceae and Lamiaceae were found frequently, while Acanthaceae, Asclepiadaceae and Pit-tosporaceae had a low frequency (Appendix 1-10). Dodonaea angustifolia L. f., Becium grandiflorum, Euclea racemosa and Acacia et-baica Schweinf. had a higher abundance and density of individuals while Clutia lanceolata, Justicia schimperiana and Morus alba had a low abundance and density. Exclosures of the age group more than 30 years old and the foot slope had a higher plant frequency, abundance and density while grazing land of the age group less than 10 years old and upper elevation recorded the lowest (Table 3). The density of woody plants in central and northern Ethiopia were found higher in exclosures, while lower in open area (Mengistu et al., 2005).

Table 2. Diversity of plants in exclosures and adjacent grazing lands with increasing age of exclosures and slope gradient

Taxa_S Individuals Dominance_D Simpsonl-D Shannon_H Evenness_eAH/S

Land use Exclosure 60 4589 0.1022 0.8978 2.847 0.2872

Grazing 28 1425 0.1193 0.8807 2.512 0.4402

< 10 18 1066 0.1952 0.8048 2.033 0.4243

Age (year) 10-20 23 1764 0.1757 0.8243 2.208 0.3954

20-30 37 1469 0.1269 0.8731 2.501 0.3297

>30 49 1702 0.05767 0.9423 3.181 0.4913

Foot 56 2255 0.07922 0.9208 3.036 0.3718

Slope position Middle 49 1967 0.09916 0.9008 2.773 0.3267

Upper 42 1776 0.1087 0.8913 2.654 0.3383

Table 3. Woody plants frequency, abundance and density in exclosures and adjacent grazing land with increasing with age of exclosures and slope position_

Factors Parameters Frequency (FR) Percent (%) Abundance (AB) Density (DE)

Land use Exclosure 699 100 4589 4267.8

Open area 292 100 1425 1325.3

>30 328 100 1702 3233.8

Age grouops 20-30 266 100 1466 2785.4

10-20 231 100 1764 3351.6

<10 166 100 1066 2025.4

Foot 408 100 2255 3157.0

Slope Middle 317 100 1967 2753.8

Upper 266 100 1776 2486.4

Availability of nutrients in exclosures and grazing lands with increasing age of exclosures and elevation gradient

The chemical soil properties of exclosures were significantly more favourable for plant development than of grazing land (Table 4). This result is supported by Mekuria (2010). Grazing impact on soil properties depends on the grazing intensity. An ungrazed site of 33 years old had higher values of pH, available P and Mg compared to a moderately grazed site (Ajorlo et al., 2011) and the concentrations of available P, total N, Ca, Mg, and K decreased after 1.5 years of heavy grazing, compared with an ungrazed control in a tropical pasture. The texture had no significant difference in all age groups and elevation except among ex-closures and adjacent grazing land. The chemical soil properties at older age exclosures had values of pH, EC, P, N, K, OC, OM better for plant development than the three young age groups of exclo-sures. The availability of chemical soil properties decreased with decreasing age of the exclosures. This shows a better result for plant development than by Minal & Anil (2012), who noted the following data: pH (5.1-6.1), EC (dsm-1) (0.22-0.28), OC % (0.32-0.04) and P (mg x kg-1) (4.2-7.7). The foot of a slope had better chemical soil properties

than the middle and upper slope and EC was significantly higher at the foot slope and followed by middle and upper slope respectively which is in agreement with Mekuria (2010), who found higher nutrients at the foot slope. Except for EC the middle and upper slopes had no significantly different values (p > 0.05).

Conclusions

Diversity and species richness were higher in the exclosures than in grazing lands. Among exclosures these parameters were higher in exclo-sures older than 30 years and at the foot of the slope. The grazing land, the youngest exclosures and the upper slope had a lower species richness and diversity. The contents of chemical soil properties showed a significant difference and were the highest in the oldest exclosures and at the foot slope. The open grazing land, the youngest exclosures and the upper slope showed poor chemical properties. Exclosures can have multiple importances in improving soil and plants diversity. Ex-closures have environmental, social and economic benefits to the local communities. Even though the exclosure management regime has a potential to rehabilitate the degraded areas, integrating soil and water conservation measures and indigenous

Table 4. Soil properties in exclosures and adjacent grazing lands with increasing age of exclosures and elevation gradient

Mean pH Mean EC Mean P Mean K Mean % N Mean % OC Mean % OM

Land uses Exclosure Gl 7.752 i 0.035a 7.295 i 0.035b 15.898 i 0.382a 9.424 i 0.382b 9.143 i 0.455a 2.918 i 0.455b 8.80 i 0.296a 3.748 i 0.295b 0.565 i 0.010a 0.275 i 0.010b 1.727 i 0.057a 0.339 i 0.057b 2.977 i 0.099a 0.584 i 0.099b

<10 7.240 i 0.053c 10.402 i 0.646b 2.214 i 0.676c 3.857 i 0.496c 0.345 i 0.023b 0.442 i 0.113c 0.762 i 0.196c

Age groups 10-20 7.492 i 0.053b 11.989 i 0.646b 5.747 i 0.676b 6.146 i 0.496b 0.403 i 0.023b 0.952 i 0.113b 1.642 i 0.196b

20-30 7.606 i 0.053ab 12.414 i 0.646b 6.169 i 0.676b 6.71 i 0.496ab 0.428 i 0.023ab 1.250 i 0.113ab 2.154 i 0.196ab

>30 7.757 i 0.053a 15.838 i 0.646a 9.993 i 0.676a 8.37 i 0.501a 0.503 i 0.023a 1.487 i 0.113a 2.564 i 0.196a

Foot 7.718 i 0.048a 14.281 i 0.588a 7.205 i 0.661a 6.664 i 0.471a 0.478 i 0.020a 1.221 i 0.107a 2.106 i 0.184a

Elevation Middle 7.506 i 0.048b 12.450 i 0.588ab 5.759 i 0.661a 6.396 i 0.467a 0.409 i 0.020b 1.035 i 0.107ab 1.784 i 0.184ab

Upper 7.348 i 0.048b 11.252 i 0.588c 5.128 i 0.661a 5.733 i 0.467a 0.372 i 0.020b 0.842 i 0.107b 1.451 i 0.184b

Means in the = pmm, EC = same column followed by same = ms/m, Gl = Grazing land letter do not differ significantly at P < 0.05, mean value three replications ± SE, with units of Av.P = ppm, Av.K

enrichment planting in the exclosures could be a better method of management to accelerate the rehabilitation process of the exclosures and to increase the diversity and density of woody plant species in the exclosures. Additional research is needed to establish the interactive relationships among soil properties, soil fertilities, survival rate and growth rate of woody plant species in the ex-closures.

References

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Appendix 1. AB, DE, FR, LF, trees and shrubs of all woody plants (P = 0.000)

R.no Plants of the Tigray highlands Vernacular name Family LF FR % AB DE Family frequency

1 Abutilon longicuspe Hochst. ex A. Rich. Tsa'eda embwak Malvaceae S 7 0.7 10 5.0 Family FR %

2 Acaia decurrens Willd. Dikerens Fabaceae T 13 1.3 59 29.5 Acanthaceae 1 0.1

3 Acacia etbaica Schweinf. Seraw Fabaceae T 53 5.3 439 219.5 Aloeaceae 16 1.6

4 Acacia lahai Benth. Lahai Fabaceae T 6 0.6 27 13.5 Anacardiaceae 30 3.0

5 Acacia saligna (Labill.) Wendl. Acacha Fabaceae T 24 2.4 195 97.5 Apocynaceae 37 3.7

6 Acokanthera schimpri (A. DC.) Schweinf. Mebt'a Apocynaceae T 11 1.1 99 49.5 Asclepiadaceae 1 0.1

7 Acacia seyal Delile Tsa'eda che'a Fabaceae T 65 6.6 223 111.5 Asteraceae 5 0.5

8 Aloe vera (A. barbadensis) (L.) Burm. f. E'are Aloeaceae S 16 1.6 163 81.5 Berberidaceae 2 0.2

9 Becium grandiflorum (Lam.) Pic. Serm. Tebeb Lamiaceae S 77 7.8 853 426.5 Bignoniaceae 5 0.5

10 Berberis holstii Engl. Zinkila Berberidaceae S 1 0.1 4 2.0 Boraginaceae 2 0.2

11 Buddleja polystachya Fresen. Metere Loganiaceae S 9 0.9 10 5.0 Buddleiaceae 6 0.6

12 Calpurinia aurea (Aiton) Benth. Htsawts Fabaceae S 41 4.1 177 88.5 Cactaceae 7 0.7

13 Cadaba farinosa Forssk. Taum chena Capparidaceae S 7 0.7 16 8.0 Capparidaceae 7 0.7

14 Carissa spinarum L. Agam Apocynaceae S 26 2.6 35 17.5 Celastraceae 97 9.8

15 Clutia lanceolata Forssk. Bokokot Euphorbiaceae S 1 0.1 1 0.5 Combretaceae 17 1.7

16 Leucas oligocephala Hook. f. Swakerni Labiatae S 17 1.7 170 85.0 Cupressaceae 73 7.4

17 Cordia africana Lam. Aqui Boraginaceae T 2 0.2 2 1.0 Ebenaceae 96 9.7

18 Croton macrostachyus Hochst. ex Delile Tanbuque Euphorbiaceae T 17 1.7 33 16.5 Ericaceae 2 0.2

19 Cupressus lusitanica Mill. Tsihidi ferenji Cupressaceae T 8 0.8 30 15.0 Euphorbiaceae 31 3.1

20 Diospyros abyssinica (Hiern) F. White Kumel a'awaf Ebenaceae T 2 0.2 2 1.0 Fabaceae 227 22.9

21 Diplostigma canescens K. Schum. Halengi Asclepiadaceae S 1 0.1 2 1.0 Flacourtiaceae 10 1.0

22 Dichrostachys cinerea (L.) Wight & Arn. Gonnok Fabaceae S 2 0.2 5 2.5 Lamiaceae 81 8.2

23 Dovyalis abyssinica (A. Rich.) Warb. Aihada Flacourtiaceae S 3 0.3 3 1.5 Loganiaceae 9 0.9

24 Dodonaea angustifolia L. f. Tahsos Sapindaceae S 55 5.5 1060 530.0 Loranthaceae 2 0.2

25 Ekebergia capensis Sparrm. Kot Meliaceae T 4 0.4 10 5.0 Malvaceae 7 0.7

26 Erica arborea L. Shanto Ericaceae S 2 0.2 2 1.0 Meliaceae 4 0.4

27 Euphorbia abyssinica J.F. Gmel. Kolkual Euphorbiaceae T 13 1.3 41 20.5 Moraceae 3 0.3

28 Eucalyptus camaldulensis Dehnh. Keyh bahr zaf Myrtaceae T 37 3.7 191 95.5 Myricaceae 8 0.8

29 Eucalyptus globulus Labill. Tsa'eda bahr zaf Myrtaceae T 17 1.7 58 29.0 Myrtaceae 54 5.4

30 Euclea racemosa L. Kuli'aw Ebenaceae S 94 9.5 847 423.5 Oleaceae 29 2.9

31 Ficus vasta Forssk. Da'aro Moraceae T 2 0.2 2 1.0 Oliniaceae 11 1.1

32 Grewia ferruginea Hochst. ex A. Rich. Tsimkuya Tiliaceae S 3 0.3 6 3.0 Phytolaccaceae 7 0.7

33 Grevillea robusta A.Cunn. ex R. Br. Gravila Proteaceae T 3 0.3 8 4.0 Pittosporaceae 1 0.1

34 Juniperus procera Hochst. ex Endl. Tsihidi habesha Cupressaceae T 65 6.6 256 128.0 Polygonaceae 11 1.1

35 Justicia schimperiana (Hochst. ex Nees) T. Anderson Shim'aya Acanthaceae S 1 0.1 1 0.5 Proteaceae 3 0.3

36 Maytenus arbutifolia (Hochst. ex A. Rich.) R. Wilczek Atat Celastraceae S 81 8.2 364 182.0 Rhamnaceae 9 0.9

37 Maytenus senegalensis (Lam.) Exell Argudi/kebkeb Celastraceae T 16 1.6 24 12.0 Rosaceae 8 0.8

38 Morus alba L. Yferenj injori Moraceae T 1 0.1 1 0.5 Rubiaceae 2 0.2

39 Myrica salicifolia Hochst. ex A. Rich. Nihibi Myricaceae S 8 0.8 16 8.0 Salicaceae 5 0.5

40 Nuxia congesta R. Br. ex Fresen. Atkaro Buddleiaceae T 6 0.6 8 4.0 Sapindaceae 55 5.5

41 Olea europaea L. Awli'a Oleaceae T 30 3.0 72 36.0 Tiliaceae 3 0.3

42 Olinia rochetiana A. Juss. Shgmesrhi Oliniaceae S 10 1.0 60 30.0 Vitaceae 7 0.7

43 Oncoba spinosa Forssk. Eqot Flacourtiaceae T 7 0.7 18 9.0 Total 991 100.0

44 Opuntiaficus indica (L.) Mill. Beles Cactaceae S 7 0.7 65 32.5

45 Osyris quadripartita Salzm. ex Decne. Kerets Loranthaceae T 2 0.2 2 1.0

46 Otostegia integrifolia Benth. Mesaguh/ chi'andog Lamiaceae S 6 0.6 23 11.5

47 Phytolacca dodecandra L'Hér. Shimiti Phytolaccaceae S 7 0.7 13 6.5

48 Pittosporum viridiflorum Sims Chequente Pittosporaceae T 1 0.1 3 1.5

49 Prunus africana (Hook. f.) Kalkman Tikur incheti Rosaceae T 5 0.5 20 10.0

50 Psydrax schimperiana (A. Rich.) Bridson Zahak Rubiaceae T 2 0.2 2 1.0

51 Rhus glutinosa Hochst. ex A. Rich. Mengi Anacardiaceae T 15 1.5 38 19.0

52 Rhamnus prinoids L'Hér. Gesho Rhamnaceae S 9 0.9 46 23.0

53 Rhus retinorrhoea Steud. ex A. Rich. Teta'alo Anacardiaceae T 7 0.7 11 5.5

54 Rhoicissus tridentata (L. f.) Wild & R.B. Drumm. Karshiro Vitaceae S 7 0.7 18 9.0

55 Rosa abyssinica R. Br. Konteftefe Rosaceae S 3 0.3 6 3.0

56 Rumex nervosus Vahl Hakot Polygonaceae S 10 1.0 34 17.0

57 Salix mucronata (S. subserrata) Thunb. Kwaa Salicaceae T 5 0.5 17 8.5

58 Schinus molle L. Qundo berbere Anacardiaceae T 8 0.8 20 10.0

59 Senna singueana (Delile) Lock Hambhambo Fabaceae S 23 2.3 65 32.5

60 Stereospermum kunthianum Cham. Argzana Bignoniaceae T 5 0.5 13 6.5

61 Vernonia amygdalina Delile Total Grawa Asteraceae S 5 991 0.5 100 15 6014 7.5 3007

Hereafter: AB - Abundance, FR - Frequency, LF - Life form (S - shrub, T - tree), DE - density.

Appendix 2. AB, DE, FR, LF, trees and shrubs of woody plants in exclosures (P = 0.000)

R.no Plant species in exclosures Vernacular name Family LF FR % AB DE Family frequency

1 Abutilon longicuspe Hochst. ex A. Rich. Tsa'eda embwak Malvaceae S 6 0.9 9 8.4 Family FR %

2 Acaia decurrens Willd. Dikerens Fabaceae T 13 1.9 59 54.9 Acanthaceae 1 0.1

3 Acacia etbaica Schweinf. Seraw Fabaceae T 28 4.0 326 303.2 Aloeaceae 4 0.6

4 Acacia lahai Benth. Lahai Fabaceae T 6 0.9 27 25.1 Anacardiaceae 30 4.3

5 Acacia saligna (Labill.) Wendl. Acacha Fabaceae T 24 3.4 195 181.4 Apocynaceae 32 4.6

6 Acokanthera schimpri (A. DC.) Schweinf. Mebti'a Apocynaceae T 10 1.4 97 90.2 Asclepiadaceae 1 0.1

7 Acacia seyal Delile Tsa'eda che'a Fabaceae T 44 6.3 173 160.9 Asteraceae 5 0.7

8 Aloe vera (A. barbadensis) (L.) Burm. f. E'are Aloeaceae S 4 0.6 14 13.0 Berberidaceae 2 0.3

9 Becium grandiflorum (Lam.) Pic. Serm. Tebeb Lamiaceae S 53 7.6 708 658.4 Bignoniaceae 5 0.7

10 Berberis holstii Engl. Zinkila Berberidaceae S 1 0.1 4 3.7 Boraginaceae 2 0.3

11 Buddleja polystachya Fresen. Metere Loganiaceae S 5 0.7 6 5.6 Buddleiaceae 5 0.7

12 Calpurinia aurea (Aiton) Benth. Htsawts Fabaceae S 22 3.1 122 113.5 Capparidaceae 4 0.6

13 Cadaba farinosa Forssk. T'aum chena Capparidaceae S 4 0.6 11 10.2 Celastraceae 69 9.9

14 Carissa spinarum L. Agam Apocynaceae S 22 3.1 29 27.0 Combretaceae 12 1.7

15 Clutia lanceolata Forssk. Bokokot Euphorbiaceae S 1 0.1 1 0.9 Cupressaceae 50 7.2

16 Leucas oligocephala Hook. f. Swakerni Labiatae S 12 1.7 137 127.4 Ebenaceae 53 7.6

17 Cordia africana Lam. Aqui Boraginaceae T 2 0.3 2 1.9 Ericaceae 1 0.1

18 Croton macrostachyus Hochst. ex Delile Tanbuque Euphorbiaceae T 12 1.7 27 25.1 Euphorbiaceae 26 3.7

19 Cupressus lusitanica Mill. Tsihidi ferengi Cupressaceae T 7 1.0 29 27.0 Fabaceae 149 21.3

20 Diospyros abyssinica(Hiern) F. White Kumel a'awaf Ebenaceae T 2 0.3 2 1.9 Flacourtiaceae 10 1.4

21 Diplostigma canescens K. Schum. Halengi Asclepiadaceae S 1 0.1 2 1.9 Lamiaceae 58 8.3

22 Dichrostachys cinerea (L.) Wight & Arn. Gonnok Fabaceae S 2 0.3 5 4.7 Loganiaceae 5 0.7

23 Dovyalis abyssinica (A. Rich.) Warb. Aihada Flacourtiaceae S 3 0.4 3 2.8 Loranthaceae 2 0.3

24 Dodonaea angustifolia L. f. Tahsos Sapindaceae S 49 7.0 1038 965.3 Malvaceae 6 0.9

25 Ekebergia capensis Sparrm. Kot Meliaceae T 4 0.6 10 9.3 Meliaceae 4 0.6

26 Erica arborea L. Shanto Ericaceae S 1 0.1 1 0.9 Moraceae 3 0.4

27 Euphorbia abyssinica J.F. Gmel. Kolkual Euphorbiaceae T 13 1.9 41 38.1 Myricaceae 8 1.1

28 Eucalyptus camaldulensis Dehnh. Keyh bahr zaf Myrtaceae T 17 2.4 76 70.7 Myrtaceae 22 3.1

29 Eucalyptus globulus Labill. Tsa'eda bahr zaf Myrtaceae T 5 0.7 24 22.3 Oleaceae 26 3.7

30 Euclea racemosa L. Kuli'aw Ebenaceae S 51 7.3 466 433.4 Oliniaceae 8 1.1

31 Ficus vasta Forssk. Da'aro Moraceae T 2 0.3 2 1.9 Phytolaccaceae 7 1.0

32 Grewia ferruginea Hochst. ex A. Rich. Tsimkuya Tiliaceae S 3 0.4 6 5.6 Pittosporaceae 1 0.1

33 Grevillea robusta A. Cunn. ex R. Br. Gravila Proteaceae T 3 0.4 8 7.4 Polygonaceae 3 0.4

34 Juniperus procera Hochst. ex Endl. Tsihidi habesha Cupressaceae T 43 6.2 196 182.3 Proteaceae 3 0.4

35 Justicia schimperiana (Hochst. ex Nees) T. Anderson Shim'aya Acanthaceae S 1 0.1 1 0.9 Rhamnaceae 9 1.3

36 Maytenus arbutifolia (Hochst. ex A. Rich.) R. Wilczek Atat Celastraceae S 60 8.6 265 246.5 Rosaceae 8 1.1

37 Maytenus senegalensis (Lam.) Exell Argudi Celastraceae T 9 1.3 15 14.0 Rubiaceae 1 0.1

38 Morus alba L. Yferenj injori Moraceae T 1 0.1 1 0.9 Salicaceae 5 0.7

39 Myrica salicifolia Hochst. ex A. Rich. Nihibi Myricaceae S 8 1.1 16 14.9 Sapindaceae 49 7.0

40 Nuxia congesta R. Br. ex Fresen. Atkaro Buddleiaceae T 5 0.7 6 5.6 Tiliaceae 3 0.4

41 Olea europaea L. Awli'a Oleaceae T 27 3.9 68 63.2 Vitaceae 7 1.0

42 Olinia rochetiana A. Juss. Beye/Shimesrhi Oliniaceae S 7 1.0 57 53.0 Total 699 100.0

43 Oncoba spinosa Forssk. Eqot Flacourtiaceae T 7 1.0 18 16.7

44 Osyris quadripartita Salzm. ex Decne. Kerets Loranthaceae T 2 0.3 2 1.9

45 Otostegia integrifolia Benth. Chi'andog Lamiaceae S 6 0.9 23 21.4

46 Phytolacca dodecandra L'Hér. Shimiti Phytolaccaceae S 7 1.0 13 12.1

47 Pittosporum viridiflorum Sims Chequente Pittosporaceae T 1 0.1 3 2.8

48 Prunus africana (Hook. f.) Kalkman Tikur incheti Rosaceae T 5 0.7 20 18.6

49 Psydrax schimperiana (A. Rich.) Bridson Zahak Rubiaceae T 1 0.1 1 0.9

50 Rhus glutinosa Hochst. ex A. Rich. Mengi Anacardiaceae T 15 2.1 38 35.3

51 Rhamnus prinoids L'Hér. Gesho Rhamnaceae S 9 1.3 46 42.8

52 Rhus retinorrhoea Steud. ex A. Rich. Teta'alo Anacardiaceae T 7 1.0 11 10.2

53 Rhoicissus tridentata (L. f.) Wild & R.B. Drumm. Karshiro Vitaceae S 7 1.0 18 16.7

54 Rosa abyssinica R. Br. Konteftefe Rosaceae S 3 0.4 6 5.6

55 Rumex nervosus Vahl Hakot Polygonaceae S 3 0.4 8 7.4

56 Salix mucronata (S. subserrata) Thunb. Kwaa Salicaceae T 5 0.7 17 15.8

57 Schinus molle L. Qundo berbere Anacardiaceae T 8 1.1 20 18.6

58 Senna singueana (Delile) Lock Hambhambo Fabaceae S 10 1.4 32 29.8

59 Stereospermum kunthianum Cham. Argzana Bignoniaceae T 5 0.7 13 12.1

60 Vernonia amygdalina Delile Total Grawa Asteraceae T 5 699 0.7 100 15 4589 14.0 4267.8

Appendix 3. AB, DE, FR, LF, trees and shrubs of woody plants in grazing land (P = 0.000)

R.no Plant species of grazing lands Vernacular name Family LF FR % AB DE Family frequency

1 Abutilon longicuspe Hochst. ex A. Rich. Tsa'eda embwak Malvaceae S 1 0.3 1 0.9 Families FR %

2 Acacia etbaica Schweinf. Seraw Fabaceae T 2б 8.6 113 Ю5.1 Aloeaceae 12 4.1

3 Acokanthera schimpri (A. DC.) Schweinf. Mebt'a Apocynaceae T 1 0.3 2 1.9 Apocynaceae б 1.7

4 Acacia seyal Delile Tsa'eda che'a Fabaceae T 21 7.2 5Ü 46.б Buddleiaceae 1 0.3

б Aloe vera (L.) Burm. f. E'are Aloeaceae S 12 4.1 149 138.6 Cactaceae 7 2.4

6 Becium grandiflorum (Lam.) Pic. Serm. Tebeb Lamiaceae S 24 8.2 14б 134.9 Capparidaceae 3 1.0

7 Buddleja polystachya Fresen. Metere Loganiaceae S 4 1.4 4 3.7 Celastraceae 28 9.6

8 Calpurinia aurea (Aiton) Benth. Htsawts Fabaceae S 19 6.б 35 5L2 Combretaceae б 1.7

9 Cadaba farinose Forssk. Taum chena Capparidaceae S 3 1.0 б 4.7 Cupressaceae 23 7.9

10 Carissa spinarum L. Agam Apocynaceae S 4 1.4 6 Ebenaceae 43 14.7

11 Leucas oligocephala Hook. f. Swakerni Labiatae S б 1.7 33 30.7 Ericaceae 1 0.3

12 Croton macrostachyus Hochst. ex Delile Tanbuque Euphorbiaceae T б 1.7 6 3.6 Euphorbiaceae б 1.7

13 Cupressus lusitanica Mill. Tsihidi ferenji Cupressaceae T 1 0.3 1 0.9 Fabaceae 78 26.7

14 Dodonaea angustifolia L. f. Tahsos Sapindaceae S 6 2.1 22 20.б Lamiaceae 23 7.9

Erica arborea L. Shanto Ericaceae S 1 0.3 1 0.9 Loganiaceae 4 1.4

16 Eucalyptus camaldulensis Dehnh. Keyh bahr zaf Myrtaceae T 20 6.8 11б 107.0 Malvaceae 1 0.3

17 Eucalyptus globulus Labill. Tsa'eda bahr zaf Myrtaceae T 12 4.1 34 31.6 Myrtaceae 32 11.0

18 Euclea racemose L. Kuli'aw Ebenaceae S 43 14.7 381 354.3 Oleaceae 3 1.0

19 Juniperus procera Hochst. ex Endl. Tsihidi habesha Cupressaceae T 22 l.S 60 35.8 Oliniaceae 3 1.0

20 Maytenus arbutifolia (Hochst. ex A. Rich.) R. Wilczek Atat Celastraceae S 21 7.2 99 92.1 Polygonaceae 8 2.7

21 Maytenus senegalensis (Lam.) Exell Argudi/kebkeb Celastraceae T 7 2.4 9 8.4 Rubiaceae 1 0.3

22 Nuxia congesta R. Br. ex Fresen. Atkaro Buddleiaceae T 1 0.3 2 1.9 Sapindaceae 6 2.1

23 Olea europaea L. Awli'a Oleaceae T 3 1.0 4 3.7 Total 292 100.0

24 Olinia rochetiana A. Juss. Shgmesrhi Oliniaceae S 3 1.0 3 2.8

2б Opuntia ficus indica (L.) Mill. Beles Cactaceae S 7 2.4 6б 60.б

26 Psydrax schimperiana (A.Rich.) Bridson Zahak Rubiaceae T 1 0.3 1 0.9

27 Rumex nervosus Vahl Hakot Polygonaceae S 7 2.4 26 24.2

28 Senna singueana (Delile) Lock Total Hambhambo Fabaceae S 13 292 100 33 142б 30.7 1325.3

Appendix 4. AB, DE, FR, LF, trees and shrubs of woody plants in foot elevation (P = 0.000)

R.no Plant of foot slope Vernacular name Family LF FR % AB DE Family frequency

1 Abutilón longicuspe Hochst. ex A. Rich. Tsa'eda embwak Malvaceae S 2 0.5 2 2.8 Family FR %

2 Acaia decurrens Willd. Dikerens Fabaceae T 7 1.7 31 43.4 Acanthaceae 1 0.2

3 Acacia etbaica Schweinf. Seraw Fabaceae T 18 4.4 126 176.4 Aloeaceae 2 0.5

4 Acacia lahai Benth. Lahai Fabaceae T 3 0.7 11 15.4 Anacardiaceae 13 3.2

5 Acacia saligna (Labill.) Wendl. Acacha Fabaceae T 10 2.5 72 100.8 Apocynaceae 14 3.4

6 Acokanthera schimpri (A. DC.) Schweinf. Mebti'a Apocynaceae T 3 0.7 27 37.8 Asteraceae 3 0.7

7 Acacia seyal Delile Tsa'eda che'a Fabaceae T 29 7.1 101 141.4 Berberidaceae 1 0.2

8 Aloe vera (A. barbadensis) (L.) Burm. f. E'are Aloeaceae S 2 0.5 3 4.2 Bignoniaceae 3 0.7

9 Becium grandiflorum (Lam.) Pic. Serm. Tebeb Lamiaceae S 25 6.1 393 550.2 Boraginaceae 2 0.5

10 Berberis holstii Engl. Zinkila Berberidaceae S 1 0.2 2 2.8 Buddleiaceae 3 0.7

11 Buddleja polystachya Fresen. Metere Loganiaceae S 3 0.7 4 5.6 Cactaceae 3 0.7

12 Calpurinia aurea (Aiton) Benth. Htsawts Fabaceae S 14 3.4 41 57.4 Capparidaceae 1 0.2

13 Cadaba farinosa Forssk. T'aum chena Capparidaceae S 1 0.2 1 1.4 Celastraceae 35 8.6

14 Carissa spinarum L. Agam Apocynaceae S 12 2.9 14 19.6 Combretaceae 7 1.7

15 Clutia lanceolata Forssk. Bokokot Euphorbiaceae S 1 0.2 1 1.4 Cupressaceae 26 6.4

16 Leucas oligocephala Hook. f. Swakerni Labiatae S 7 1.7 82 114.8 Ebenaceae 30 7.4

17 Cordia africana Lam. Aqui Boraginaceae T 2 0.5 2 2.8 Ericaceae 1 0.2

18 Croton macrostachyus Hochst. ex Delile Tanbuque Euphorbiaceae T 11 2.7 26 36.4 Euphorbiaceae 19 4.7

19 Cupressus lusitanica Mill. Tsihidi ferenji Cupressaceae T 2 0.5 5 7 Fabaceae 96 23.5

20 Dovyalis abyssinica (A. Rich.) Warb. Aihada Flacourtiaceae S 1 0.2 1 1.4 Flacourtiaceae 6 1.5

21 Dodonaea angustifolia L. f. Tahsos Sapindaceae S 22 5.4 254 355.6 Lamiaceae 29 7.1

22 Ekebergia capensis Sparrm. Kot Meliaceae T 3 0.7 4 5.6 Loganiaceae 3 0.7

23 Erica arborea L. Shanto Ericaceae S 1 0.2 1 1.4 Malvaceae 2 0.5

24 Euphorbia abyssinica J.F. Gmel. Kolkual Euphorbiaceae T 7 1.7 23 32.2 Meliaceae 3 0.7

25 Eucalyptus camaldulensis Dehnh. Keyh bahr zaf Myrtaceae T 13 3.2 74 103.6 Moraceae 2 0.5

26 Eucalyptus globulus Labill. Tsa'eda bahir zaf Myrtaceae T 7 1.7 22 30.8 Myricaceae 6 1.5

27 Euclea racemosa L. Kuli'aw Ebenaceae S 30 7.4 304 425.6 Myrtaceae 20 4.9

28 Ficus vasta Forssk. Da'aro Moraceae T 1 0.2 1 1.4 Oleaceae 11 2.7

29 Grewia ferruginea Hochst. ex A. Rich. Tsimkuya Tiliaceae S 1 0.2 2 2.8 Oliniaceae 6 1.5

30 Grevillea robusta A. Cunn. ex R. Br. Gravila Proteaceae T 2 0.5 7 9.8 Phytolaccaceae 6 1.5

31 Juniperus procera Hochst. ex Endl. Tsihidi habesha Cupressaceae T 24 5.9 93 130.2 Pittosporaceae 1 0.2

32 Justicia schimperiana (Hochst. ex Nees) T. Anderson Shim'aya Acanthaceae S 1 0.2 1 1.4 Polygonaceae 8 2.0

33 Maytenus arbutifolia (Hochst. ex A. Rich.) R. Wilczek Atat Celastraceae S 29 7.1 157 219.8 Proteaceae 2 0.5

34 Maytenus senegalensis (Lam.) Exell Argudi Celastraceae T 6 1.5 9 12.6 Rhamnaceae 6 1.5

35 Morus alba L. Yferenj injori Moraceae T 1 0.2 1 1.4 Rosaceae 3 0.7

36 Myrica salicifolia Hochst. ex A. Rich. Nihibi Myricaceae S 6 1.5 14 19.6 Rubiaceae 2 0.5

37 Nuxia congesta R. Br. ex Fresen. Atkaro Buddleiaceae T 3 0.7 4 5.6 Salicaceae 3 0.7

38 Olea europaea L. Awli'a Oleaceae T 11 2.7 25 35 Sapindaceae 22 5.4

39 Olinia rochetiana A. Juss. Beye/Shimesrhi Oliniaceae S 6 1.5 44 61.6 Tiliaceae 1 0.2

40 Oncoba spinosa Forssk. Eqot Flacourtiaceae T 5 1.2 16 22.4 Vitaceae 6 1.5

41 42 Opuntiaficus indica (L.) Mill. Otostegia integrifolia Benth. Beles Mesaguh/ chi'andog Cactaceae Lamiaceae S S 3 5 0.7 1.2 23 12 32.2 16.8 Total 408 100

43 Phytolacca dodecandra L'Hér. Shimiti Phytolaccaceae S 6 1.5 12 16.8

44 Pittosporum viridiflorum Sims Chequente Pittosporaceae T 1 0.2 3 4.2

45 Prunus africana (Hook. f.) Kalkman Tikur incheti Rosaceae T 3 0.7 16 22.4

46 Psydrax schimperiana (A. Rich.) Bridson Zahak Rubiaceae S 2 0.5 2 2.8

47 Rhus glutinosa Hochst. ex A. Rich. Mengi/hatami Anacardiaceae T 5 1.2 7 9.8

48 Rhamnus prinoids L'Hér. Gesho Rhamnaceae S 6 1.5 37 51.8

49 Rhus retinorrhoea Steud. ex A. Rich. Teta'alo Anacardiaceae T 2 0.5 4 5.6

50 Rhoicissus tridentata (L. f.) Wild & R.B. Drumm. Karshiro Vitaceae S 6 1.5 17 23.8

51 Rumex nervosus Vahl Hakot Polygonaceae S 7 1.7 27 37.8

52 Salix mucronata (S. subserrata) Thunb. Kwaa Salicaceae T 3 0.7 13 18.2

53 Schinus molle L. Qundo berbere Anacardiaceae T 6 1.5 16 22.4

54 Senna singueana (Delile) Lock Hambhambo Fabaceae S 14 3.4 43 60.2

55 Stereospermum kunthianum Cham. Argzana Bignoniaceae T 3 0.7 11 15.4

56 Vernonia amygdalina Delile Total Grawa Asteraceae T 3 408 0.7 100 11 2255 15.4 3157

Appendix 5. AB, DE, FR, LF, trees and shrubs of woody plants in middle elevation (P = 0.000)

R.no Plants of middle slope Vernacular name Family LF FR % AB DE Family frequency

1 Abutilon longicuspe Höchst. ex Tsa'eda embwak Malvaceae S 4 1.3 6 8.4 Family FR %

A. Rich.

2 Acaia decurrens Willd. Dikerens Fabaceae T 3 0.9 15 21 Aloeaceae 8 2.5

3 Acacia etbaica Schweinf. Seraw Fabaceae T 19 6.0 205 287 Anacardiaceae 9 2.8

4 Acacia lahai Benth. Lahai Fabaceae T 1 0.3 8 11.2 Apocynaceae 10 3.2

5 Acacia saligna (Labill.) Wendl. Acacha Fabaceae T 8 2.5 64 89.6 Asteraceae 2 0.6

6 Acokanthera schimpri (A. DC.) Mebt'a Apocynaceae T 4 1.3 44 61.6 Bignoniaceae 2 0.6

Schweinf.

7 Acacia seyal Delile Tsa'eda che'a Fabaceae S 21 6.6 70 98 Buddleiaceae 2 0.6

8 Aloe vera (A. barbadensis) (L.) E'are Aloeaceae S 8 2.5 59 82.6 Cactaceae 3 0.9

Burm. f.

9 Becium grandiflorum (Lam.) Pic. Tebeb Lamiaceae S 28 8.8 236 330.4 Capparidaceae 4 1.3

Serm.

10 Buddleja polystachya Fresen. Metere Loganiaceae S 3 0.9 3 4.2 Celastraceae 28 8.8

11 Calpurinia aurea (Aiton) Benth. Htsawts Fabaceae S 16 5.0 86 120.4 Combretaceae 7 2.2

12 Cadaba farinosa Forssk. Taum chena Capparidaceae S 4 1.3 9 12.6 Cupressaceae 21 6.6

13 Carissa spinarum L. Agam Apocynaceae S 6 1.9 7 9.8 Ebenaceae 33 10.4

14 Leucas oligocephala Hook.f. Swakerni Labiatae S 7 2.2 48 67.2 Euphorbiaceae 7 2.2

15 Croton macrostachyus Hochst. ex Delile Tanbuque Euphorbiaceae T 4 1.3 5 7 Fabaceae 76 24.0

16 Cupressus lusitanica Mill. Tsihidi ferengi Cupressaceae T 2 0.6 4 5.6 Flacourtiaceae 3 0.9

17 Dichrostachys cinerea (L.) Wight & Am. Gonnok Fabaceae S 1 0.3 3 4.2 Lamiaceae 29 9.1

18 Dovyalis abyssinica (A. Rich.) Aihada Flacourtiaceae S 1 0.3 1 1.4 Loganiaceae 3 0.9

Warb.

19 Dodonaea angustifolia L. f. Tahsos Sapindaceae S 19 6.0 413 578.2 Loranthaceae 1 0.3

20 Ekebergia capensis Sparrm. Kot Meliaceae T 1 0.3 6 8.4 Malvaceae 4 1.3

21 Euphorbia abyssinica J.F. Gmel. kolqual Euphorbiaceae T 3 0.9 12 16.8 Meliaceae 1 0.3

22 Eucalyptus camaldulensis Dehnh. Keyh bahr zaf Myrtaceae T 14 4.4 72 100.8 Moraceae 1 0.3

23 Eucalyptus globulus Labill. Tsa'eda bahr zaf Myrtaceae T 5 1.6 23 32.2 Myricaceae 2 0.6

24 Euclea racemosa L. Kuli'aw Ebenaceae S 33 10.4 265 371 Myrtaceae 19 6.0

25 Ficus vasta Forssk. Da'aro Moraceae T 1 0.3 1 1.4 Oleaceae 9 2.8

26 Juniperus procera Hochst. ex Endl. Tsihidi habesha Cupressaceae T 19 6.0 67 93.8 Oliniaceae 2 0.6

27 Maytenus arbutifolia (Hochst. ex Atat Celastraceae S 23 7.3 87 121.8 Phytolaccaceae 1 0.3

A. Rich.) R. Wilczek

28 Maytenus senegalensis (Lam.) Exell Argudi/kebkeb Celastraceae T 5 1.6 6 8.4 Polygonaceae 1 0.3

29 Myrica salicifolia Hochst. ex A. Nihibi Myricaceae S 2 0.6 2 2.8 Rhamnaceae 3 0.9

Rich.

30 Nuxia congesta R. Br. ex Fresen. Atkaro Buddleiaceae T 2 0.6 3 4.2 Rosaceae 4 1.3

31 Olea europaea L. Awli'a Oleaceae T 9 2.8 21 29.4 Salicaceae 2 0.6

32 Olinia rochetiana A. Juss. Shgmesrhi Oliniaceae S 2 0.6 2 2.8 Sapindaceae 19 6.0

33 Oncoba spinosa Forssk. Eqot Flacourtiaceae T 2 0.6 2 2.8 Vitaceae 1 0.3

34 Opuntiaficus indica (L.) Mill. Beles Cactaceae S 3 0.9 37 51.8 Total 317 100.0

35 Osyris quadripartita Salzm. ex Kerets Loranthaceae T 1 0.3 1 1.4

Decne.

36 Otostegia integrifolia Benth. Chi'andog Lamiaceae S 1 0.3 11 15.4

37 Phytolacca dodecandra L'Hér. Shimiti Phytolaccaceae S 1 0.3 1 1.4

38 Prunus africana (Hook. f.) Kalkman Tikur incheti Rosaceae T 2 0.6 4 5.6

39 Rhus glutinosa Hochst. ex A. Rich. Mengi Anacardiaceae T 5 1.6 7 9.8

40 Rhamnus prinoids L'Hér. Gesho Rhamnaceae S 3 0.9 9 12.6

41 Rhus retinorrhoea Steud. ex A. Teta'alo Anacardiaceae T 2 0.6 2 2.8

Rich.

42 Rhoicissus tridentata (L. f.) Wild Karshiro Vitaceae S 1 0.3 1 1.4

& R.B. Drumm.

43 Rosa abyssinica R. Br. Konteftefe Rosaceae S 2 0.6 5 7

44 Rumex nervosus Vahl Hakot Polygonaceae S 1 0.3 1 1.4

45 Salix mucronata (S. subserrata) Kwaa Salicaceae T 2 0.6 4 5.6

Thunb.

46 Schinus molle L. Qundo berbere Anacardiaceae T 2 0.6 4 5.6

47 Senna singueana (Delile) Lock Hambhambo Fabaceae S 7 2.2 19 26.6

48 Stereospermum kunthianum Cham. Argzana Bignoniaceae T 2 0.6 2 2.8

49 Vernonia amygdalina Delile Grawa Asteraceae T 2 0.6 4 5.6

Total 317 100 1967 2753.8

Appendix 6. AB, DE, FR, LF, trees and shrubs of woody plants in upper elevation (P = 0.002)

R.no Plant in upper slope Vernacular name Family LF FR % AB DE Family frequency

1 Abutilon longicuspe Hochst. ex A. Rich. Tsa'eda embwak Malvaceae S 1 0.4 2 2.S Family FR %

2 Acaia decurrens Willd. Dikerens Fabaceae T 3 1.1 13 1S.2 Aloeaceae б 2.3

3 Acacia etbaica Schweinf. Seraw Fabaceae T 1б б.0 10S 1б1.2 Anacardiaceae 8 3.0

4 Acacia lahai Benth. Lahai Fabaceae T 2 0.S S 11.2 Apocynaceae 13 4.9

б Acacia saligna (Labill.) Wendl. Acacha Fabaceae T б 2.3 39 82.б Asclepiadaceae 1 0.4

б Acokanthera schimpri (A. DC.) Schweinf. Mebti'a Apocynaceae T 4 1.б 2S 39.2 Berberidaceae 1 0.4

l Acacia seyal Delile Tsa'eda che'a Fabaceae T З.б 32 72.8 Buddleiaceae 1 0.4

S Aloe vera (A. barbadensis) (L.) Burm. f. E'are Aloeaceae S б 2.3 101 141.4 Cactaceae 1 0.4

9 Becium grandiflorum (Lam.) Pic. Serm. Tebeb Lamiaceae S 23 8.б 224 313.б Capparidaceae 2 0.8

10 Berberis holstii Engl. Zinkila Berberidaceae S 1 0.4 2 2.S Celastraceae 34 12.8

11 Buddleja polystachya Fresen. Metere Loganiaceae S 3 1.1 3 4.2 Combretaceae 3 1.1

12 Calpurinia aurea (Aiton) Benth. Htsawts Fabaceae S 10 3.S 30 70 Cupressaceae 2б 9.8

13 Cadaba farinosa Forssk. Taum chena Capparidaceae S 2 0.S б S.4 Ebenaceae 33 12.4

14 Carissa spinarum L. Agam Apocynaceae S 9 3.4 14 19.б Ericaceae 1 0.4

Leucas oligocephala Hook. f. Swakerni Labiatae S 3 1.1 40 36 Euphorbiaceae б 1.9

1б Croton macrostachyus Hochst. ex Delile Tanbuque Euphorbiaceae T 2 0.S 2 2.S Fabaceae 35 20.l

1l Cupressus lusitanica Mill. Tsihidi ferengi Cupressaceae T 4 1.б 21 29.4 Flacourtiaceae 1 0.4

1S Diospyros abyssinica(Hiern) F. White Kumel a'awaf Ebenaceae T 2 0.S 2 2.S Lamiaceae 23 8.б

19 Diplostigma canescens K. Schum. Halengi Asclepiadaceae S 1 0.4 2 2.S Loganiaceae 3 1.1

20 Dichrostachys cinerea (L.) Wight & Arn. Gonnok Fabaceae S 1 0.4 2 2.S Loranthaceae 1 0.4

21 Dovyalis abyssinica (A. Rich.) Warb. Aihada Flacourtiaceae S 1 0.4 1 1.4 Malvaceae 1 0.4

22 Dodonaea angustifolia L. f. Tahsos Sapindaceae S 14 5.3 393 350.2 Myrtaceae 3.6

23 Erica arborea L. Shanto Ericaceae S 1 0.4 1 1.4 Oleaceae 9 3.4

24 Euphorbia abyssinica J.F. Gmel. Kolkual Euphorbiaceae T 3 1.1 б S.4 Oliniaceae 3 1.1

2б Eucalyptus camaldulensis Dehnh. Keyh bahr zaf Myrtaceae T 10 3.S 4б б4.4 Polygonaceae 2 0.8

2б Eucalyptus globulus Labill. Tsa'eda bahr zaf Myrtaceae T б 1.9 12 16.8 Proteaceae 1 0.4

2l Euclea racemosa L. Kuli'aw Ebenaceae S 31 11.7 278 3S9.2 Rosaceae 1 0.4

2S Grewia ferruginea Hochst. ex A. Rich. Tsimkuya Tiliaceae S 2 0.S 4 3.6 Sapindaceae 14 5.3

29 Grevillea robusta A. Cunn. ex R. Br. Gravila Proteaceae T 1 0.4 1 1.4 Tiliaceae 2 0.8

30 Juniperus procera Hochst. ex Endl. Tsihidi habesha Cupressaceae T 22 S.3 9б 134.4 Total 2бб 100

31 Maytenus arbutifolia (Hochst. ex A. Rich.) R. Wilczek Atat Celastraceae S 32 12.0 120 168

32 Maytenus senegalensis (Lam.) Exell Argudi Celastraceae T 2 0.S 9 12.б

33 Nuxia congesta R. Br. ex Fresen. Atkaro Buddleiaceae T 1 0.4 1 1.4

34 Olea europaea L. Awli'a Oleaceae T 9 3.4 2б 3б.4

Зб Olinia rochetiana A. Juss. Shigmesrhi Oliniaceae S 3 1.1 14 19.б

3б Opuntia ficus indica (L.) Mill. Beles Cactaceae S 1 0.4 б l

3l Osyris quadripartita Salzm. ex Decne. Kerets Loranthaceae T 1 0.4 1 1.4

3S Rhus glutinosa Hochst. ex A. Rich. Mengi Anacardiaceae T б 1.9 S 11.2

39 Rhus retinorrhoea Steud. ex A. Rich. Teta'alo Anacardiaceae T 3 1.1 б l

40 Rosa abyssinica R. Br. Konteftefe Rosaceae S 1 0.4 1 1.4

41 Rumex nervosus Vahl Hakot Polygonaceae S 2 0.S б S.4

42 Senna singueana (Delile) Lock Total Hambhambo Fabaceae S 2 2бб 0.S 100 3 177б 4.2 2486.4

Appendix 7. AB, DE, FR, LF, trees and shrubs of woody plants in less than 10 age (P = 0.000)

R.no Plant species in < 10 years old Vernacular name Family LF FR % AB DE Family frequency

1 Acacia decurrens Willd. Dikerens Fabaceae T 4 2.4 13 24.7 Family FR %

2 Acacia etbaica Schweinf. Seraw Fabaceae T 15 9.0 138 262.2 Aloeaceae 4 2.4

3 Acacia seyal Delile Tsa'eda che'a Fabaceae T 10 6.0 30 57.0 Apocynaceae 2 1.2

4 Aloe vera (A. barbadensis) (L.) Burm. f. E'are Aloeaceae S 4 2.4 7 13.3 Celastraceae 16 9.6

5 Becium grandiflorum (Lam.) Pic. Serm. Tebeb Lamiaceae S 36 21.7 325 617.5 Combretaceae 3 1.8

6 Calpurinia aurea (Aiton) Benth Htsawts Fabaceae S 4 2.4 21 39.9 Cupressaceae 14 8.4

7 Carissa spinarum L. Agam Apocynaceae S 2 1.2 2 3.8 Ebenaceae 33 19.9

8 Leucas oligocephala Hook. f. Swakerni Labiatae S 3 1.8 15 28.5 Euphorbiaceae 8 4.8

9 Dodonaea angustifolia L. f. Tahsos Sapindaceae S 1 0.6 1 1.9 Fabaceae 37 22.3

10 Euphorbia abyssinica J.F. Gmel. kolqual Euphorbiaceae T 8 4.8 25 47.5 Lamiaceae 38 22.9

11 Euclea racemosa L. Kuli'aw Ebenaceae S 33 19.9 293 556.7 Oliniaceae 1 0.6

12 Juniperus procera Hochst. ex Endl. Tsihidi habesha Cupressaceae T 14 8.4 76 144.4 Polygonaceae 9 5.4

13 Maytenus arbutifolia (Hochst. ex A. Rich.) R. Wilczek Atat Celastraceae S 11 6.6 40 76.0 Sapindaceae 1 0.6

14 Maytenus senegalensis (Lam.) Exell Argudi Celastraceae T 5 3.0 9 17.1 Total 166 100.0

15 Olinia rochetiana A. Juss Beye/Shimesrhi Oliniaceae S 1 0.6 14 26.6

16 Otostegia integrifolia Benth. Mesaguh/chi'andog Lamiaceae S 3 1.8 16 30.4

17 Rumex nervosus Vahl Hakot Polygonaceae S 8 4.8 29 55.1

18 Senna singueana (Delile) Lock Total Hambhambo Fabaceae S 4 166 2.4 100 12 1066 22.8 2025.4

Appendix 8. AB, DE, FR, LF, trees and shrubs of woody plants in between 10 and 20 age (P = 0.000)

R.no Plant species in between 10 & 20 age Vernacular name Family LF FR % AB DE Family frequency

1 Acaia decurrens Willd. Dikerens Fabaceae T 9 3.9 46 87.4 Family FR %

2 Acacia lahai Benth. Lahai Fabaceae T 6 2.6 27 51.3 Aloeaceae 2 0.9

3 Acacia saligna (Labill.) Wendl. Acacha Fabaceae T 21 9.1 179 340.1 Anacardiaceae 1 0.4

4 Acacia .seyal Delile Tsa'eda che'a Fabaceae T 12 5.2 52 98.8 Celastraceae 35 15.2

5 Aloe vera (L.) Burm. f. E'are Aloeaceae S 2 0.9 5 9.5 Cupressaceae 35 15.2

6 Becium grandiflorum (Lam.) Pic. Serm. Tebeb Lamiaceae S 10 4.3 81 153.9 Ebenaceae 18 7.8

7 Calpurinia aurea (Aiton) Benth. Htsawts Fabaceae S 11 4.8 36 68.4 Euphorbiaceae 5 2.2

8 Clutia lanceolate Forssk. Bokokot Euphorbiaceae S 1 0.4 1 1.9 Fabaceae 71 30.7

9 Croton macrostachyus Hochst. ex Delile Tambuque Euphorbiaceae T 4 1.7 9 17.1 Lamiaceae 13 5.6

10 Cupressus lusitanica Mill. Tsihidi ferenji Cupressaceae T 4 1.7 16 30.4 Myrtaceae 29 12.6

11 Dichrostachys cinerea (L.) Wight & Arn. Gonnok Fabaceae S 2 0.9 5 9.5 Oleaceae 1 0.4

12 Dodonaea angustifolia L. f. Tahsos Sapindaceae S 20 8.7 636 1208.4 Proteaceae 1 0.4

13 Eucalyptus camaldulensis Dehnh. Keyh bahir zaf Myrtaceae T 18 7.8 102 193.8 Sapindaceae 20 8.7

14 Eucalyptus globulus Labill. Tsa'eda bahir zaf Myrtaceae T 11 4.8 32 60.8 Total 231 100

15 Euclea racemose L. Kuli'aw Ebenaceae S 18 7.8 195 370.5

16 Grevillea robusta A. Cunn. ex R. Br. Gravilia Proteaceae T 1 0.4 4 7.6

17 Juniperus procera Hochst. ex Endl. Tsihidi habesha Cupressaceae T 31 13.4 133 252.7

18 Maytenus arbutifolia (Hochst. ex A. Rich.) R. Wilczek Atat Celastraceae S 32 13.9 169 321.1

19 Maytenus senegalensis (Lam.) Exell Argudi/kebkeb Celastraceae T 3 1.3 4 7.6

20 Olea europaea L. Awli'a Oleaceae T 1 0.4 2 3.8

21 Otostegia integrifolia Benth. Chi'andog Lamiaceae S 3 1.3 7 13.3

22 Rhus retinorrhoea Steud. ex A. Rich. Teta'alo Anacardiaceae T 1 0.4 1 1.9

23 Senna singueana (Delile) Lock Total Hambhambo Fabaceae S 10 231 4.3 100.0 22 1764 41.8 3351.6

Appendix 9. AB, DE, FR, LF, trees and shrubs of woody plants in between 20 and 30 age (P = 0.007)

R.nö Plant species in between 20 & 30 age Vernacular name Family LF FR % AB DE Family frequency

l Abutilon longicuspe Hochst. ex A. Rich. Tsa'eda embwak Malvaceae S 2 O.S 2 3.8 Family FR %

2 Acacia etbaica Schweinf. Seraw Fabaceae T 2l 10.2 22l 4l9.9 Aloeaceae 2 O.8

з Acacia saligna (Labill.) Wendl. Acacha Fabaceae T з l.l 1б 30.4 Anacardiaceae l8 б.8

4 Acokanthera schimpri (A. DC.) Schweinf. Mebti'a Apöcynaceae T з l.l l 13.3 Apocynaceae 1б б.0

5 Acacia seyal Delile Tsa'eda cha'a Fabaceae T l2 4.6 38 l2.2 Asclepiadaceae l O.4

б Aloe vera (A. barbadensis) (L.) Burm. f. E'are Alöeaceae S 2 O.S 9 H.l Berberidaceae l O.4

l Becium grandiflorum (Lam.) Pic. Serm. Tebeb Lamiaceae S 2з 8.б 332 б30.8 Capparidaceae б 2.3

S Berberis holstii Engl. Zinkila Berberidaceae S l O.4 2 3.8 Celastraceae 29 lO.9

9 Calpurinia aurea (Aiton) Benth. Htsawts Fabaceae S 4 1.6 9 H.l Combretaceae 9 3.4

lO Cadaba farinosa Forssk. Taum chena Capparidaceae S б 2.з 16 28.6 Cupressaceae 8 3.0

ll Carissa spinarum L. Agam Apöcynaceae S 13 4.9 16 28.6 Ebenaceae 2б 9.8

l2 Leucas oligocephala Hook. f. Swakerni Labiatae S 9 з.4 9l ll2.9 Euphorbiaceae 4 l.S

13 Croton macrostachyus Hochst. ex Delile Tanbuque Euphörbiaceae T 4 1.6 lO 19.0 Fabaceae 51 l9.2

l4 Cupressus lusitanica Mill. Tsihidi ferengi Cupressaceae T 4 1.6 l4 2б.б Flacourtiaceae 3 l.l

16 Diplostigma canescens K. Schum. Halengi Asclepiadaceae S l O.4 2 3.8 Lamiaceae 23 8.б

1б Dodonaea angustifolia L. f. Tahsös Sapindaceae S 24 9.O 233 48O.l Loranthaceae 2 O.8

ll Eucalyptus camaldulensis Dehnh. Keyh bahir zaf Myrtaceae T 2 O.S 2 3.8 Malvaceae 2 O.8

lS Euclea racemose L. Kuli'aw Ebenaceae S 2б 9.S 1б1 305.9 Myricaceae 4 l.S

l9 Grevillea robusta A. Cunn. ex R. Br. Gravila Pröteaceae T 2 O.S 4 1.6 Myrtaceae 2 O.8

2O Juniperus procera Hochst. ex Endl. Tshdi habesha Cupressaceae T 4 1.6 9 H.l Oleaceae 9 3.4

2l Maytenus arbutifolia (Hochst. ex A. Rich.) R. Wilczek Atat Celastraceae S 24 9.O lOS 2OS.2 Oliniaceae 8 3.0

22 Maytenus senegalensis (Lam.) Exell Argudi Celastraceae T 1.9 l 13.3 Phytolaccaceae 4 l.S

2з Myrica salicifolia Hochst. ex A. Rich. Nihibi Myricaceae S 4 1.6 S 15.2 Polygonaceae 2 O.8

24 Olea europaea L. Awli'a Oleaceae T 9 з.4 2l 39.9 Proteaceae 2 O.8

25 Olinia rochetiana A. Juss. Shgmesrhi Oliniaceae S S 3.0 26 47.Ъ Rhamnaceae 5 1.9

2б Oncoba spinosa Forssk. Eqöt Flacöurtiaceae T з l.l б 11.4 Rubiaceae 2 O.8

2l Osyris quadripartite Salzm. ex Decne. Kerets Löranthaceae T 2 O.S 2 3.8 Sapindaceae 24 9.O

2S Phytolacca dodecandra L'Hér. Shimiti Phytölaccaceae S 4 1.6 S 15.2 Vitaceae 3 l.l

29 Psydrax schimperiana (A. Rich.) Bridson Zahak Rubiaceae T 2 O.S 2 3.8 Total 2бб lOO

30 Rhus glutinosa Hochst. ex A. Rich. Mengi Anacardiaceae T 13 4.9 1б 30.4

31 Rhamnus prinoids L'Hér. Geshö Rhamnaceae S 1.9 2l 39.9

з2 Rhus retinorrhoea Steud. ex A. Rich. Teta'alö Anacardiaceae T l O.4 l 1.9

зз Rhoicissus tridentata (L. f.) Wild & R.B. Drumm. Karshirö Vitaceae S з l.l б 11.4

з4 Rumex nervosus Vahl Haköt Pölygönaceae S 2 O.S 9.6

36 Schinus molle L. Qundö berbere Anacardiaceae T 4 1.6 б 11.4

зб Senna singueana (Delile) Lock Total Hambhambö Fabaceae S 2бб 1.9 lOO.O l2 14бб 22.8 2l8S.4

Appendix 10. AB, DE, FR, LF, trees and shrubs of woody plants in greater than 30 age (P = 0.000)

R.no Plant in greater than 30 years old Vernacular name Family LF FR % AB DE Family frequency

1 Abutilón longicuspe Höchst. ex A. Rich. Tsa'eda embwak Malvaceae S 5 1.5 8 15.2 Family FR %

2 Acacia etbaica Schweinf. Seraw Fabaceae T 10 3.0 80 152.0 Acanthaceae 1 0.3

3 Acokanthera schimpri (A. DC.) Schweinf. Mebt'a Apocynaceae T 8 2.4 92 174.8 Aloeaceae 8 2.4

4 Acacia seyal Delile Tsa'eda che'a Fabaceae T 32 9.8 103 195.7 Anacardiaceae 11 3.4

5 Aloe vera (A. barbadensis) (L.) Burm. f. E'are Aloeaceae S 8 2.4 142 269.8 Apocynaceae 19 5.8

6 Becium grandiflorum (Lam.) Pic. Serm. Tebeb Lamiaceae S 7 2.1 115 218.5 Asteraceae 5 1.5

7 Berberis holstii Engl. Zinkila Berberidaceae S 1 0.3 2 3.8 Berberidaceae 1 0.3

8 Buddleja polystachya Fresen. Metere Loganiaceae S 9 2.7 10 19.0 Bignoniaceae 5 1.5

9 Calpurinia aurea (Aiton) Benth. Htsawts Fabaceae S 22 6.7 111 210.9 Boraginaceae 2 0.6

10 Cadaba farinosa Forssk. T'aum chena Capparidaceae S 1 0.3 1 1.9 Buddleiaceae 6 1.8

11 Carissa spinarum L. Agam Apocynaceae S 11 3.4 15 28.5 Cactaceae 7 2.1

12 Leucas oligocephala Hook. f. Swakerni Labiatae S 5 1.5 64 121.6 Capparidaceae 1 0.3

13 Cordia africana Lam. Aqui Boraginaceae T 2 0.6 2 3.8 Celastraceae 17 5.2

14 Croton macrostachyus Hochst. ex Delile Tanbuque Euphorbiaceae T 9 2.7 14 26.6 Combretaceae 5 1.5

15 Diospyros abyssinica (Hiern) F. White Kumel a'awaf Ebenaceae T 2 0.6 2 3.8 Cupressaceae 16 4.9

16 Dovyalis abyssinica (A. Rich.) Warb. Aihada Flacourtiaceae S 3 0.9 3 5.7 Ebenaceae 19 5.8

17 Dodonaea angustifolia L. f. Tahsos Sapindaceae S 10 3.0 170 323.0 Ericaceae 2 0.6

18 Ekebergia capensis Sparrm. Kot Meliaceae T 4 1.2 10 19.0 Euphorbiaceae 14 4.3

19 Erica arborea L. Shanto Ericaceae S 2 0.6 2 3.8 Fabaceae 68 20.7

20 Euphorbia abyssinica J.F. Gmel. Kolkual Euphorbiaceae T 5 1.5 16 30.4 Flacourtiaceae 7 2.1

21 Eucalyptus camaldulensis Dehnh. Keyh bahr zaf Myrtaceae T 17 5.2 87 165.3 Lamiaceae 7 2.1

22 Eucalyptus globulus Labill. Tsa'eda bahr zaf Myrtaceae T 6 1.8 26 49.4 Loganiaceae 9 2.7

23 Euclea racemosa L. Kuli'aw Ebenaceae S 17 5.2 200 380.0 Malvaceae 5 1.5

24 Ficus vasta Forssk. Da'aro Moraceae T 2 0.6 2 3.8 Meliaceae 4 1.2

25 Grewia ferruginea Hochst. ex A. Rich. Tsimkuya Tiliaceae S 3 0.9 6 11.4 Moraceae 3 0.9

26 Juniperus procera Hochst. ex Endl. Tsihidi habesha Cupressaceae T 16 4.9 38 72.2 Myricaceae 4 1.2

27 Justicia schimperiana (Hochst. ex Nees) T. Anderson Shim'aya Acanthaceae S 1 0.3 1 1.9 Myrtaceae 23 7.0

28 Maytenus arbutifolia (Hochst. ex A. Rich.) R. Wilczek Atat Celastraceae S 14 4.3 47 89.3 Oleaceae 19 5.8

29 Maytenus senegalensis (Lam.) Exell Argudi Celastraceae T 3 0.9 5 9.5 Oliniaceae 2 0.6

30 Morus alba L. Yferenj injori Moraceae T 1 0.3 1 1.9 Phytolaccaceae 3 0.9

31 Myrica salicifolia Hochst. ex A. Rich. Nihibi Myricaceae S 4 1.2 8 15.2 Pittosporaceae 1 0.3

32 Nuxia congesta R. Br. ex Fresen. Atkaro Buddleiaceae T 6 1.8 8 15.2 Rhamnaceae 4 1.2

33 Olea europaea L. Awli'a Oleaceae T 19 5.8 49 93.1 Rosaceae 8 2.4

34 Olinia rochetiana A. Juss. Shigmesrhi Oliniaceae S 2 0.6 21 39.9 Salicaceae 5 1.5

35 Oncoba spinosa Forssk. Eqot Flacourtiaceae T 4 1.2 12 22.8 Sapindaceae 10 3.0

36 Opuntiaficus indica (L.) Mill. Beles Cactaceae S 7 2.1 65 123.5 Tiliaceae 3 0.9

37 Phytolacca dodecandra L'Hér. Shimiti Phytolaccaceae S 3 0.9 5 9.5 Vitaceae 4 1.2

38 Pittosporum viridiflorum Sims Chequente Pittosporaceae T 1 0.3 3 5.7 Total 328 100

39 Prunus africana (Hook. f.) Kalkman Tikur incheti Rosaceae T 5 1.5 20 38.0

40 Rhus glutinosa Hochst. ex A. Rich. Mengi Anacardiaceae T 2 0.6 6 11.4

41 Rhamnus prinoids L'Hér. Gesho Rhamnaceae S 4 1.2 25 47.5

42 Rhus retinorrhoea Steud. ex A. Rich. Teta'alo Anacardiaceae T 5 1.5 9 17.1

43 Rhoicissus tridentata (L. f.) Wild & R.B. Drumm. Karshiro Vitaceae S 4 1.2 12 22.8

44 Rosa abyssinica R. Br. Konteftefe Rosaceae S 3 0.9 6 11.4

45 Salix mucronata (S. subserrata) Thunb. Kwaa Salicaceae T 5 1.5 17 32.3

46 Schinus molle L. Qundo berbere Anacardiaceae T 4 1.2 14 26.6

47 Senna singueana (Delile) Lock Hambhambo Fabaceae S 4 1.2 19 36.1

48 Stereospermum kunthianum Cham. Argzana Bignoniaceae T 5 1.5 13 24.7

49 Vernonia amygdalina Delile Total Grawa Asteraceae T 5 328 1.5 100 15 1702 28.5 3233.8

ВОССТАНОВЛЕНИЕ НАРУШЕННЫХ ЗАСУШЛИВЫХ ЗЕМЕЛЬ ПУТЕМ ИЗЪЯТИЯ ИХ ИЗ ХОЗЯЙСТВЕННОЙ ДЕЯТЕЛЬНОСТИ, ПОВЫШАЮЩЕГО РАЗНООБРАЗИЕ ДРЕВЕСНЫХ ВИДОВ И ПОЧВЕННОЕ ПИТАНИЕ, В ВЫСОКОГОРЬЯХ ТИГРАЯ, СЕВЕРНАЯ ЭФИОПИЯ

К. М. Гебремедихин, Е. Бирхане*, Т. Тадессе, Х. Гбревахид

Университет Мэкэлле, Эфиопия *e-mail: [email protected], [email protected]

Изъятие пастбищных животных и посадок деревьев было одним из методов, используемых для восстановления деградированных земель в тропических полузасушливых областях. Изъятые земли могут способствовать вторичной сукцессии лесов, улучшая почвенные условия, привлекая агентов для распространения семян и изменяя микроклимат для развития подроста. В этой статье сравнивается разнообразие древесных пород и химические свойства почв на участках изъятых из использования в разное время и на пастбищах на склонах разной экспозиции. Исследование было проведено в Северной Эфиопии на 12 участков, изъятых из использования, и на таком же количестве выпасаемых участков, расположенных в непосредственной близости, с четырьмя обработками и в трех повторностях. В ходе работы было исследовано 216 участков, из которых 108 находились на исключенных из хозяйственной деятельности участках и 108 - на общинных пастбищах. В каждой группе участков было выделено четыре класса по возрасту и три - по экспозиции склона. Данные о растительности были собраны на участках размером 100 м2. Образцы почвы для определения ее физико-химических свойств были собраны из четырех углов и центра участков размером 5 х 5 м, которые находились внутри участков размером 10 х 10 м. В общей сложности был зарегистрирован 61 вид древесных растений из 41 семейства. Разнообразие и видовое богатство были выше на участках, изъятых из сельскохозяйственной деятельности, чем на пастбищах. Среди неиспользуемых участков эти параметры были выше на тех, которые были изъяты из хозяйственной деятельности более 30 лет назад и которые расположены у подножий склонов. Пастбища, недавно изъятые из пользования участки и расположенные на вершине склонов показали наиболее низкие значения этих параметров. Химические свойства почвы были значительно благоприятнее для растительности на изъятых из пользования участках, а среди них - на участках, имеющих самый большой возраст и расположенных у подножия склонов (за исключением содержания фосфора) по сравнению со значениями этих показателей на пастбищах, на недавно изъятых из пользования участках и расположенных на верхних частях склонов. Таким образом, изымаемые из хозяйственного использования участки играют важную роль в повышении разнообразия древесных пород и улучшения химических свойств почвы в засушливых областях.

Ключевые слова: изъятые из хозяйственной деятельности участки, разнообразие древесных растений, химические свойства почвы, экспозиция склона