Community perceptions towards invasion of Prosopis juliflora, utilization, and its control options in Afar region, Northeast Ethiopia.

This study aimed to assess community perceptions towards invasion of Prosopis juliflora, utilization, and its control options in Afar region, Northern Ethiopia. Using purposive sampling and stratified random methods, 20 members of key informants and 154 households from four sites of Awash Fentale and Amibara Districts were selected. For data analysis, we used Kruskal Wallis non-parametric tests of K independent samples. About 30% of respondents in Amibara and 29% in Awash Fentale reported that Prosopis juliflora was largely introduced into their landscape by livestock. It showed that 29% of the respondents in Awash Fentale and 41% in Amibara responded that Prosopis juliflora largely invaded and affected rangelands. Morevover, about 1% of respondents in Awash Fentale and 14% in Amibara argued that Prosopis juliflora hindered movements of livestock. In addition, 30% of respondents in Amibara and 29% in Awash Fentale believe that Prosopis juliflora was largely dispersed by livestock. It showed that 20% of households in Awash Fentale and 41% in Amibara have the notion that Prosopis juliflora majorly impacted rangelands. Whereas 1.3% of respondents in Awash Fentale and 14% in Amibara argued that Prosopis juliflora have hampered the movement of livestock. Thus, the afromentioned findings are implications for management of rangelands. With regard to the control of Prosopis juliflora invasions, 12% of respondents in Awash Fentale and 33% in Amibara District tried control its expansion by fire. About 10% of respondents in Awash Fentale and 9% in Amibara district managed Prosopis juliflora expansion by its utilization, whereas, in Awash Fentale (11%) and Amibara (8%) households indicated that invasion of Prosopis juliflora could be controlled by mechanical methods. It is advisable to do some managerial work to reverse these impacts as perceived by local communities in the study area to avert the aggressive proliferation of Prosopis juliflora in the region.

Introduction

Prosopis juliflora (Sw.) DC. (hereafter P. juliflora) is a shrub or tree species native to Mexico, Central, and Northern America. From its native ranges, P. juliflora spread to Africa, Asia, and Austria [1]. In Africa, P. juliflora was first introduced in Senegal in 1822 and continued to establish in other countries at different times [2]. In Ethiopia, it was first introduced in the 1970s to restore degraded lands [3]. After its introduction, P. juliflora started to aggressively expand. It has been become an invasive or noxious weed in several African countries including Kenya, Ethiopia, Sudan, Senegal, and South Africa [1,7]. In the introduced countries, P. juliflora expansion increased. For example, PENHA [4] reported that the global cover of P. juliflora as a whole was 50 million hectares and P. juliflora covered about 5 million hectares in Africa in 2014 while Shiferaw et al. [5] reported a land cover of 1.20x106 ha by P. juliflora. It was encroaching at a rate of 3.11 x 104 ha yr-1 and constituted 12.3% of the land surface in the Afar region. Pittroff [6] also reported that P. juliflora cover was more than 1.80 x 106 ha of Afar region. It has now become an invasive or noxious weed in several African countries including Kenya, Ethiopia, Sudan, Senegal, and South Africa [1,7].

Thus, community perception will play a significant role in rangeland management and lay the conceptual foundation for the management of the invasion by P. juliflora. Study by Dafalla [8] indicats that educated people are more supportive of the eradication of P. juliflora than people that are not educated. This is debatable! Less educated people are to some degree dependent only on wood of P. juliflora for livelihood support. In contrary, in Ethiopia, local people have negative attitudes towards P. juliflora. They believe that the species has replaced economically important pasture and farmlands, and threatening pastoral and agro-pastoral livelihoods. It is also thought to have impacted human and animal health. The species is has become a threat to road traffic, and water infrastructures. In addition, the invasion has turned into a major driver of biodiversity loss in the invaded regions [3].

Inadequate management practices like prevention of its invasion into rangelands by local development interventions and social conflicts over grazing lands facilitated the invasion of P. juliflora in Afar region [9-11]. The perceptions of Afar pastoralists concerning the P. juliflora invasion are negative because it impacts their livelihoods and environment they inhabit [12]. Likewise, the majority of the households in the Gewane district of Afar region have not appreciated the positive and significant association of P. juliflora with their income diversifications [13]. Palatable grasses including Chrysopogon plumulosus Hochst., Cenchrus ciliaris L., Setaria verticillata (L.), and other valuable woody species such as Acacia tortilis (Frossk.), A. senegal (L.) Willd., A. nilotica (L.) Willd. ex. Del. was being replaced by inavsaion of the species. Thus, the present study aimed to assess community perceptions towards (i) the intoruciton and invasion (ii) the socio-economic values of the species, and (iii) controlling options of P. juliflora in Afar region of Ethiopia.

Materials and methods

Description of the study area

Amibara District is located in between altitudes of 741 and 746 m.a.s.l. It is located between 9° 19′ 44″ N and 40° 10′ 52″ E, whereas Awash Fentale is located at 700 and 1000 m.a.s.l. and 9° 10′ 00″ N and 40° 03′ 33″ E.

The mean annual temperature for the Awash Fentale District was 27 ± 2°C, while the mean minimum was 16.7 ± 1.97°C. The mean maximum temperature was 37.8 ± 2.1°C (Fig 1a). The mean annual temperature for Amibara District was 26.8 ± 4°C, whereas the mean minimum temperature was 13.8 ± 4.3°C and the mean maximum was 38.2 ± 2.3°C (Fig 1). The study areas are located within semiarid and arid agro-ecologies of Ethiopia. The annual precipitation of Awash Fentale and Amibara districts was 490 ± 34 mm and 416 ± 31 mm respectively (Fig 1). A total population of 83, 851 and 40,901 was living in Amibara and Awash Fentale respectively [14]. Ninety percent of Afar people are pastoralists, while another 10% are considered as agro-pastoralists [15].

Fig 1

(a) Thirty-one year climate diagram for Awash Fentale District and (b) Fifteen year climate diagram for Amibara District [16].

Afar region is characterized by desert and semi-desert scrubland, Acacia-Commiphora woodland, and bush land vegetation types [17]. This study was conducted in Acacia-Commiphora woodland and desert and semi-desert scrubland with vegetation subtype Acacia-Commiphora woodland and bushland. The characteristic herbaceous vegetation consisted of Chrysopogon, Sporobolus, Dactyloctenium, cymbopogon, and Cynodon species. The woody vegetation was mainly composed of Acacia Senegal (L.) Willd., Acacia oerfota (Forssk.) Schweinf., Acacia nilotica (L.) Willd. ex. Del., Acacia tortilis (Frossk.) Hayne, Acacia mellifera (Vahl) Benth., Acalypha acrogyna Pax, Cadaba rotundifolia Forssk., Dobera glabra (Forssk.) Poir., Grewia tenax (Forssk.) Fiori, Salvadora persica L., Balanites aegyptiaca (L.) Del., and Ziziphus spina-christi L. [17].

Data collection

Socio-demographicof household characteristics

We used semistructured and structured questionnaires to collect through key informants interview and household survey. Primary data were being collected through discussion with key informants and sampled households using pre-tested semistructured and structured questionnaires. For data collection, a three stage sampling method i.e., districts were purposely selected while household respondents were randomly selected. We took random households for the household from two sites from each district namely Diduba and Kebena from Awash Fentale and Kurkura and Andido from Amibara disricts [18]. The respondents for households were randomly selected females and males that were heads of the family. The memebers of the key informants were selected from district experts that were related to natural resources management experts, team leaders of district natural resources manament, office leaders of each district agricultural and natural resources, and adiminstrators of each district.

Diduba and Kurkura sites were less affected by P. juliflora compared to Kebena and Andido. A toral of 154 household which is 5% of total households was selected for household survey from the four sites. The selected households were from lightly, moderately, and highly invaded sites. Sample households from total households in the study sites were then stratified into wealth, sex and, age categories and then selected using simple random sampling technique from the total households in the sites.

Based on the information from key informants households which had > 10 camels, > 20 cattle and > 60 small ruminants (goats and sheep) were categorized as rich. Those owning 1–10 camels, 5–10 cattle, and 10–60 small ruminants were categorized as medium households while hoseholds with no camels, < 5 cattle and < 10 small ruminants were categorized as poor households [19].

Data analysis

Qualitative and quantitative methods were used during the data analyses. The data were not normally distributed, thus non-parametric tests of K independent samples of Kruskal Wallis of χ2 for mean separtion was used. The empirical multinomial logit model for this study was specified as [20]: Where yi, the dependent variable, is the wealth or socioeconomic status of pastoralists, xi’s are the included explanatory variables. The dependent variable (yi) is defined as follows: 1 for the poor pastoralists, 2 for the middle-class pastoralists, and 3 for the rich pastoralists. yi is also defined as 1 for male and 2 for female pastoralists; 1 as the youth (1–18 years), 2 for adult class (19–60 years), and 3 for old class (> 65 years) of pastoralists. Aside from the wealth status, other variables initially considered for inclusion in the model include age, sex, and education status of the agropastoralists and pastoralists. Then, explanatory vs. response variables were used for the empirical valuations, all the analyses were done using the XX and YY procedures of descriptive statstics in SPSS Software [21].

Households were significantly different among their opinions regarding questions raised such as: what were their mode of living, how P. juliflora was introduced, why it was introduced into their sites, preferred site for P. juliflora regeneration, benefits they get from P.juliflora, use of P. juliflora for traditional medicine, the preparation of P. juliflora for traditional medicine for human disease, livestock disease, preparation method for traditional medicine for livestock diseases from P. juliflora (P < 0.05). However, the rests of the households’ perceptions didn’t show significant (P > 0.05) (S2 Table).

The variable definitions and measurements are given in S1 Table. For assessing community awareness towards the invasion of P. juliflora, 32% from Awash Fentale and 66.2% households from Amibara District were used for the interview. Among the respondents, 71% and 29% were male and female households, respectively (Table 1). Of which 1%, 91%, and 8% of households fall in young, middle, and elder age groups, respectively. The family size of households ranged from 0–13 and mean value of 6. About 95% of the respondents had no formal education, 1% had primary educations, and 2% attended secondary and post-secondary education. Among the respondents, 27% were representatives of peasant associations and also had different positions in government offices.

Table 1

Household characteristics of Awash Fenatle and Amibara Districts.

Explanatory variable	Mean of household characteristics	SE	Minimum	Maximum	df	χ 2
District	1.7	223.2	1	2	1	16.23
Site	2.8	154.0	1	4	3	19.25
Sex	1.3	226.5	1	2	1	24.96
Age	2.1	285.2	1	3	2	230.7
Wealth	1.4	211.0	1	3	2	83.08
Relationship to household head	1.8	116.7	1	8	6	525.36
Household type	1.6	142.6	1	6	5	354.75
Household number	5.7	93.9	0	13	13	79.27
Education of household head	0.1	216.9	0	3	3	400.23
Education of household member	0.8	163.8	0	3	5	161.66

Results

Histrory of P. juliflora introduction

We found that about 30% of the respondent in Amibara and 29% in Awash Fentale districts thought that P. juliflora was introduced to Afar by livestock. About 19% of the respondents in Amibara and 3% Awash Fentale districts thought argued that P. juliflora was introduced to by a foreigner came to Amibara area. A small proportion of the respondents in Amibara (6.5%) and Awash Fentale (1.3%) thought that the species was introduced by local people (Table 2). About 22% of key inormatns in Amibara and 33% in Awash Fentale thought that the species was introduced by a foreigner (Fig 2).

Table 2

Agents for the introduction of P. juliflora into Awash Fentale and Amibara Didtricts.

Response		Frequency	%
Local people	Awash Fentale	2	1.3
	Amibara	10	7
Natural	Awash Fentale	0	0.0
	Amibara	5	3
Foreigners	Awash Fentale	5	3
	Amibara	29	19
Livestock	Awash Fentale	44	29
	Amibara	46	30
Wild animals	Awash Fentale	0	0.0
	Amibara	1	0.6
Others	Awash Fentale	0	0.0
	Amibara	11	7

Fig 2

Household responses on the reasons for the introduction of P. juliflora into Awash Fenatle and Amibara Districts.

Purposes of P. juliflora introduction

About 31% of the respondents in Amibra and 10% in Awash Fentale reported that fuelwood was the main reason for the introduction of P. juliflora in Afar region (Fig 2). Households in Amibara (18%) and Awash Fentale (5%) reported that the species was introduced for shade purpose (Fig 2). About 7% of the respondents in Amibara and 9% in Awash Fentale reported that the species was introduced for the purpose of soil and water conservation (Fig 2). However, 12% of the respondents in Amibra and 17% in Awas Fentale districts did not know the purpose of its introduction.

According to the key inforamts, 11% in Amibara and 22% in Awash Fentale confirmed that P. juliflora was introduced for fuelwood purposes. About 33% of the key informants in Amibara and 22% in Awash Fentale reported that the species was introduced for shade purpose (Fig 3).

Fig 3

Key informants responses for purposes of introduction of P. juliflora into Awash Fenatle and Amibara Districts.

Socio-economic values of P. juliflora

Regarding the opinions of households, the use of P. juliflora for traditional medicine, preparations of human traditional medicine from plant parts, human disease cured by P. juliflora, livestock diseases cured by P. juliflora, and preparations of livestock traditional medicine from plant parts had shown that significant variations among respondents (P < 0.05) across Districts (S2 Table). Of households, about 49% of the respondents in Amibara and 12% in Awash Fentale district reported that they got different benefits from P. juliflora (Table 3).

Table 3

Perceptions of households on benefits of P. juliflora in Awash Fenatle and Amibara Districts.

Benefits	District	Frequency	%
Shade for livestock	Awash Fentale	9	5.8
	Amibara	11	7.1
Shade for people	Awash Fentale	2	1.3
	Amibara	4	2.6
Fuel wood	Awash Fentale	10	6.5
	Amibara	66	42.9
Furniture	Awash Fentale	1	0.6
	Amibara	0	0
House construction	Awash Fentale	3	1.9
	Amibara	6	3.9
Live fence	Awash Fentale	10	6.5
	Amibara	2	1.3
Soil and Water Conservation	Awash Fentale	1	0.6
	Amibara	1	0.6
Ameliorating effects	Awash Fentale	0	0
	Amibara	1	0.6
Shelterbelt	Awash Fentale	0	0
	Amibara	1	0.6
Fodder	Awash Fentale	2	1.3
	Amibara	0	0
Combating desertification	Awash Fentale	5	3.2
	Amibara	1	0.6
Medicinal values	Awash Fentale	9	5.8
	Amibara	10	6.5

Use of P. julflora for medicinal purposes

About 10% of households in Awash Fentale and 9% in Amibara District used P. juliflora for traditional medicines. It was reported that 8% of respondents in Awash Fentale and 5% in Amibara District used P. juliflora for curing human injury that pricked by its thorns. Only 8% and 4% of respondents in Awash Fentale and Amibara District perceived that livestock injures were cured by traditional medicine of P. juliflora (Table 4).

Table 4

The use of P. juliflora for traditional medicine in Awash Fenatle and Amibara Districts.

Do you think P. juliflora used for traditional medicine?
Response	District	Frequency	%
Yes	Awash Fentale	14	10
	Amibara	14	9
No	Awash Fentale	34	22
	Amibara	85	55
I do not know	Awash Fentale	4	3
	Amibara	3	2
Which part of P. juliflora used for traditional medicine?
Seeds or pods	Awash Fentale	14	9
	Amibara	14	9
Leaf	Awash Fentale	38	25
	Amibara	88	57
Preparation of P. juliflora for traditional medicine for human cure?
Pounding	Awash Fentale	13	8
	Amibara	11	7
I don’t know	Awash Fentale	39	25
	Amibara	91	59
Human diseases cured by traditional medicine of P. juliflora?
Wound	Awash Fentale	13	8
	Amibara	8	5
I do not know	Awash Fentale	39	25
	Amibara	93	60
Livestock diseases cured by traditional medicine of P. juliflora?
Wound	Awash Fentale	12	8
	Amibara	6	4
I don’t know	Awash Fentale	40	26
	Amibara	95	62
Preparation method for traditional medicine for livestock diseases from P. juliflora?
Pounding	Awash Fentale	12	8
	Amibara	7	5
I don’t know	Awash Fentale	40	26
	Amibara	94	61

Preparation of traditional medicine from P. juliflora

For preparation of traditional medicine curing human diseases (wounds), 8% and 5% of households in Awash Fentale and Amibara responded that it cured by crushing its leaf part. But, the majority of households in Awash Fentale (25%) and Amibara (59%) didn’t know how to prepare traditional medicines for human diseases, whereas 8% and 4% of households in Awash Fentale and Amibara responded that livestock wounds cured by pounding its leaf part. But, the majority of households in Awash Fentale (26%) and Amibara (62%) didn’t know how to prepare its traditional medicines for curing livestock (Table 4).

Effects of P. juliflora

Larger number of repondents in Amibara (41%) and Awash Fentale (20%) reported that P. juliflora affected them most by invading and degrading the health of their rangelands, whereas a few hoseholds in the study districts reported that P. juliflora blocked roads e.g., human and livestock roads (Table 5).

Table 5

Impacts of P. juliflora in Awash Fenatle and Amibara Districts.

Effects	Districts	Frequency	%
Woody weedy in agricultural lands	Awash Fentale	12	8
	Amibara	7	5
Invasion into grazing lands	Awash Fentale	30	20
	Amibara	63	41
Blocking roads of livestock	Awash Fentale	2	1.3
	Amibara	22	14
Blocking roads of human beings	Awash Fentale	2	1.3
	Amibara	9	6
Invasion of water courses, drying rivers and water tables	Awash Fentale	0	0
	Amibara	1	0.6
Lack of aesthetic value due to its monoculture	Awash Fentale	5	1.3
	Amibara	0	0

Effect of P. juliflora invasion and land use changes

About 16% of households in Awash Fenatle and 27% in Amibara District showed that conversions of land use land cover were caused by invasion of P. juliflora, whereas 11% in Awash Fenatle District and 16% in Amibara were caused by farm land expansion. In addition, 0.6% of respondents in Awash Fentale and 6% in Amibara Distrcits reported that the cause for conversions of land uses were drought or shortage of rainfall (Table 6).

Table 6

The causes of land use land cover conversions in Awash Fentale and Amibara Districts.

Causes	District	Frequency	%
Livestock production beyond the carrying capacity/overgrazing	Awash Fentale	17	11
	Amibara	25	16
Farm land expansion	Awash Fentale	4	3
	Amibara	0	0.0
Anthropogenic	Awash Fentale	0	0.0
	Amibara	1	0.6
Invasion of P. juliflora	Awash Fentale	24	16
	Amibara	42	27
Moisture stress	Awash Fentale	2	1.3
	Amibara	0	0.0
Drought or shortage of rainfall	Awash Fentale	1	0.6
	Amibara	9	6
Toxic effects of P.juliflora	Awash Fentale	2	1.3
	Amibara	24	16

Households responded that 13% in Awash Fenatle and 35% in Amibara District changed from woodlands into P. juliflora, whereas 16% in Awash Fentale and 27% in Amibara district changed from grazing lands into P. juliflora cover. Moreover, 3% in Awash Fentale and 27% households in Amibara District reveald that water bodies changed into the P. juliflora cover (Fig 4).

Fig 4

Conversion of land uses due to P. juliflora inavsion in last 10 years in Awash Fentale and Amibara Districts.

Effects of P. juliflora invasion and its control

Of the hoseholds, 3% in Awash Fentale and 6% in Amibara had the attitudes that P. juliflora formed impenetrable thicket which hindered the easy movements of human beings around. Results also show that 11% of key informants in Awash Fentale and 22% in Amibara District argued that prime grazing lands of Afar region were invaded by P. juliflora (Fig 5). It was argued that 55% of households in Amibara and 27% in Awash Fenatle Districts reported that P. juliflora had negative impacts on biodiversity. However, the rest 11% in Amibara and 7% in Awash Fentale Districts had positive impacts on biodiversity. In addition, the majority of households (45%) indicated P. juliflora affected livestock in Amibara District and 27% in Awash Fentale District (Table 7).

Fig 5

Responses of key informants about impacts of P. juliflora in Awash Fenatle and Amibara Districts.

Table 7

Types of impacts on biodiversity in Awash Fenatle and Amibara Districts.

What kinds of impacts biodiversity on biodiversity?
	District	Frequency	%
Positive	Awash Fentale	10	7
	Amibara	17	11
Negative	Awash Fentale	42	27
	Amibara	85	55
What type of biodiversity affected by P. juliflora?
Livestock	Awash Fentale	42	27
	Amibara	69	45
Plants	Awash Fentale	10	7
	Amibara	31	20
Human beings	Awash Fentale	0	0
	Amibara	2	1.3
Which will be the most affected biodiversity by P. juliflora?
Livestock	Awash Fentale	47	31
	Amibara	69	45
Plants	Awash Fentale	5	3
	Amibara	29	19
Human beings	Awash Fentale	0	0
	Amibara	1	0.6
Wild animals	Awash Fentale	0	0
	Amibara	3	2

As a result, 33% of key informants in Awash Fentale and 22% in Amibara confirmed that livestock production and productivity reduced. In Awash Fentale and Amibara District, 7% and 11% of households agreed that P. juliflora impacted biodiversity. About 44% and 22% of key informants in Awash Fentale and Amibara also confirmed as an invasion of P. juliflora had negative impacts on biodiversity in terms of the reduction of species diversity and the rest 11% and 22% of key informants in Awash Fentale and Amibara perceived that P. juliflora didn’t affect species diversity (Fig 5).

About 27% of households in Awash Fentale and 45% in Amibara District responded that livestock were the most affected by P. juliflora invasions. In addition, 7% and 20% of respondents in Awash Fentale and Amibara responded that plants affected by P. juliflora invasions. 21% and 38% of household respondents in Awash Fentale and Amibara District responded that P. juliflora had impacts on plants. About 12% hoseholds (in Awash Fentale) and 33% (in Amibara) had attitudes that livestock were among those affected by the invasion of P. juliflora (Table 8).

Table 8

Perceptions of key informants on impacts of P. juliflora on biodiversity in Awash Fenatle and Amibara Districts.

What kinds of impacts of P. juliflora on biodiversity?
Response	District	Frequency	%
Positive	Awash Fentale	1	11
	Amibara	2	22
Negative	Awash Fentale	4	44
	Amibara	2	22
What type of biodiversity affected by P. juliflora?
Livestock	Awash Fentale	2	22
	Amibara	4	44
Human beings	Awash Fentale	1	11
	Amibara	0	0
Plants	Awash Fentale	2	22
	Amibara	0	0
What type of biodiversity most affected by P. juliflora?
Livestock	Awash Fentale	3	33
	Amibara	4	44
Plants	Awash Fentale	2	22
	Amibara	1	11

In Awash Fentale (10%) and Amibara Districts (9%) households had forwarded their suggestions that invasion of P. juliflora could overcome through management by utilization; whereas, in Awash Fentale (12%) and Amibara (33%) households indicated that invasion of P. juliflora could be controlled by fire. The other 11% households in Awash Fenatle and 8% in Amibara District reported that invasion of P. juliflora could be controlled by mechamical methods such as: mechanical control by cutting mature trees, mechanical control by uprooting mature trees, mechanical control by cutting juvenile stems, and mechanical control by uprooting juvenile stems (Fig 6).

Fig 6

Responses of households about the control of invasion of P. juliflora in Awash Fentale and Amibara Districts.

Note: CU = Manage by utilization, MCCMS = Mechanical control by cutting mature stems, MCUMS = Mechanical control by uprooting mature stems, MCCJS = Mechanical control by cutting juvenile stems, MCUJS = Mechanical control by uprooting juvenile stems.

About 22% key informants (in Awash Fentale) and 44% (in Amibara) had attitudes that livestock were among those affected by the invasion of P. juliflora. Furthermore, in Awash Fentale (22%) and Amibara (11%) key informants indicated that invasion of P. juliflora reduced plant species diversity. In Awash Fentale (56%) and Amibara districts (44%) key informants had forwarded their suggestions that invasion of P. juliflora could overcome through management by utilization. Unless the invasion of the species can be controlled in the future, in the Awash Fentale (22%) and in Amibara District (44%) key informants informed that prime grazing lands will be overtaken by its invasion (Fig 7).

Fig 7

Responses of key informants about the control of invasion of P. juliflora in Awash Fentale and Amibara Districts.

Discussion

Lifestyle of households

The majority of households in Awash Fentale were agro-pastoralists than those in Amibara District. The reason could be due to the existence of wetlands around Kebena River in Kebena site of Awash Fentale that most households engaged in farming and livestock rearing activities. Similarly, Tegegn [22] indicated that most households in the Gewane district of Ethiopia were agro-pastoral ways of living.

Few households in the study areas engaged in non-farm activities and obtained their incomes from daily labor wages and petty trades shopping in small scale. Similar findings by Shackleton [23] state that households engaged in non-farm activities obtained their incomes in other engagements including employment in government institutions. Moreover, in the arid Kalahari of South Africa, Shackleton [24] argued that few households engaged in non-farm activities and earned their incomes from daily labor activities.

Households’ perceptions to the introduction history of P. juliflora

In the study sites, the reasons for the introduction of P. juliflora varied among households and key informants. The reasons could be due to little knowledge on who introduced P. juliflora and its means introduction into a new inavsion [25]. Reports also show that the introduction of P. juliflora was not clear in Afar region in particular and Africa in general [26].

Similar findings by [27] reveal that introduction of most exotic plant species were related to lifestyle changes of communities and contradictions in views and perceptions. Mwangi and Swallow [28] argued that purposes of introduction of P. juliflora into most countries of Africa remain unclear and the local people were not engaged in its introduction. Contrary to the local communities’ perceptions, research reports [29] and [30] indicate that P. juliflora was introduced by workers in Middle Awash Irrigation Project in Afar region of Ethiopia.

Households’ perceptions towards the uses of P. juiflora

The majority of key informants in both District s stated that introduction of P. juliflora was for purpose of shade. Some scholars such as [26] and [30] suggested more general views indicating the introduction was to combat desertification. According to the findings of this study, P. juliflora is used for shade purposes either for livestock or human beings [24,26,30-32]. On the other hand, a study by [12] shows that P. juliflora was used as livestock feed.

Unlike the present study, research report by Shackleton [33] reveals that farmers’ used P. juliflora for shade purposes greater than used for fuelwood and medicine. However, findings by Shackleton [34] show that the use of P. juliflora for medicinal purposes is greater that for purposes of construction and land rehabilitation. On the other hand, Shackleton [33] reported that the use of P. juliflora for medicine was greater the uses of P. juliflora for fodder, fuelwood, and shade purposes, but less than that of pods for food of children and sloving job opportunities. In contrast to the present findings, Shackleton [34] reported that most households used P. juliflora for medicinal purposes. Likewise, studies by Argaw [35] and Ibrahim [36] argue that P. juliflora used as versatile medicine and important and a potential candidate for deriving phytomedicines.

According to Preeti [36]) and Henciya [37], the curative powers of traditional medicines for human beings or livestock could be due to high contents of extracts such as flavonoids, tannins, alkaloids, quinones, or phenolic compounds that demonstrate potentials in various antimicrobial activities such as analgesic, anthelmintic, and antibiotic constituents. In Ethiopia, few literatures had reported on the parts of P. juliflora that were used for traditional medicine, on the methods of its preparation for human beings or livestock diseases, or about its curing effect. Walter [38] also reported on the use of the nectar and pollen of P. juliflora to produce honey. The author further argued that P. juliflora didn’t rank equally with those of indigenous species that had been known by people for thousands of years for their medical powers in India.

A study by Wise [39] shows from the Northern Cape of South Africa that pod of P. juliflora had medicinal properties and is being used for medicinal purposes. In addition, research report by Shackleton [32] reveals that pods used to produce organic medicine were being gathered from local traders of cities, towns, and villages across South Africa’s Northern Cape. Besides, Pasiecznik [1] reported that all parts of P. juliflora tree had uses of traditional medicines. They further reported on the occasional medicinal use of P. juliflora by Native Americans to treat the epidemic diseases of Old World Origin.

The majority of households reported that invasion of P. juliflora invaded more into rangelands in Amibara than Awash Fentale District. The reasons could be due to the initial introduction of the species into Amibara District. Similarly, Harnet [40] reported that the invasion of P. juliflora into both dry season and wet season rangelands and roadsides in the Eastern lowlands of Eritrea. A study by Argaw [34] also shows that the overall analysis of responses showed rangelands were among the impacts of P. juliflora. In addition, Ndhlovu [41] also suggested that wider areas of rangelands covered by P. juliflora invasions and reduced its grazing capacity by 34% in South Africa.

Similar research reports confirmed that intermingling growth and thorny natures of P. juliflora could be due to the formation of thicket that blocked access roads for animals or human beings [34,42-44]. Invasion of P. juliflora into rangelands made blocked the roadsides and resulted in the losses of prime grazing lands. Thus, the production and productivity of livestock in the P. juliflora invaded areas were being reduced. Several researchers such as [45-47] and [5] also confirmed that the invasion of P. juliflora resulted in the loss of prime grazing lands and ultimately the causes for the reduction of livestock production and productivity.

Overall, less positive attitudes were reflected by households about the impacts of P. juliflora than negative impacts, and this might be due to a lack of full scale awareness about the impacts of P. juliflora. Moreover, most of the respondents lost their livestock that the health of animals by P. juliflora and few of them used P. juliflora for income sources. These types of views were long-standing issues of hot debates in numerous other countries in the tropics and sub-tropics. A similar view in Sudan shows that the benefits from P. juliflora completely outweigh its detrimental effects in this particular area [48]. The individuals in the tropics and subtropics accepted P. juliflora as positive where native tree species were not growing in their area.

Studies have shown that people’s views to be shaped by the negative or positive attributes of the invasive plant species [25]. Respondents who had large number of livestock were likely to be more aware of the negative impacts of P. juliflora than the positive effects [12]. On the contrary, several types of research show that P. juliflora has negative impacts on plant diversity [39,40,49,50]. On the other hand, Maundu [51] argued that P. juliflora was an aggressive weed with both strong positive and negative attributes. The negative perceptions towards P. juliflora slowly changed back to positive attitudes for the tree after communities recognized on how to exploit the tree for their economic and social benefits [52].

The variations in the views of the stakeholders on the impacts of P. juliflora on biodiversity might be due to the difference in their knowledge and practices regarding P. julidlora. Most scholars argued that P. juliflora affected biodiversity [26,34,39,50]. Most researchers reported that the invasion of P. juliflora influenced mostly plants [53-56].

Large proportions of households in Awash Fentale District were of the opinion that human beings were being injured by the long thorns of P. juliflora [34,48,56], whereas higher proportions of households in Amibara District show that impenetrable thicket of P. juliflora blocked roadsides that hindered the easy movement of both humans and animals [11,22,28,34]. The variations in the responses were due to the difference in the severity of invasions of P. julflora and the level of knowledge level between households in the two Districts.

A report by Seid [12] shows that burning of P.juliflora was the most widely employed method to control the invasion of P. juliflora. Control of P. juliflora by burning was in line with the arguments of most key informants in the Amibara District. Most key informants in Awash Fentale on the other hand, tried to control P. juliflora invasion using chemical methods. The study by [33] reveals that control of P. juliflora by utilization that is charcoal making, fuelwood, and contruction purpose was the best method to minimize the invasion P. juliflora. In the future, if the expansion of P. juliflora is not controlled, most households will predict that it will largely invade and affect prime grazing lands [33].

Factors shaping knowledges and perceptions of households

The living modes of the communities were also likely to affect invasion of P. juliflora. Most of the time and in all places of Afar region, the communities might also hear the negative sides of P. juliflora than positive by extension agents and experts in their sites.

The most palatable part of P. juliflora by animals was leaf of P. juliflora and the most toxic plant part killing their animals after their consumptions [1]. The reasons could be due to a permanent weakening of the ability to digest cellulose in pods. This might also be due to the high sugar content of the pod that depressed the rumen bacterial cellulose activity and finally killing the animal [43,56]. In this study, the decline in the number of livestock feeds could be due to the decline in the capacity of rangelands for livestock grazing through suppressing and displacing important indigenous forage species. Similar results were reported by [3,28,41,50] from their studies in Kenya, South Africa, and Ethiopia indicate the places or countries!. Most non-formal educated households in Awash Fenatle and primary school educated households in Amibara argued that P. juliflora was being introduced by NGOs and an individuals which similar to [3,18].

Preferresd sites for invasion of P. juliflora

In Amibara and Awash Fentale District s, non-formal, primary, secondary, and tertiary-educated households ranked rangelands > homestead > mechanized farmlands > roadsides with respect to preferred sites for the establishment of P. juliflora respectively. Findings by [24,30,33] showed that rangelands were changed more into P. juliflora than other land-use types. The reason could be due to greater probability of seed dispersal by fecal droppings and abiotic suitability in the rangelands and in homesteads (e.g., moisture and high organic matter accumulation).

Conclusion

The perceptions of local communities towards invasive species depend on the level of communities’ awareness, knowledge, and practices in their socio-economic and ecological uses. The benefits of invasive species outweigh their negative effects. When this is the case, local communities tend to embrace species and retain them an ecosystem.

The majority of households in Awash Fentale and few households in Amibara District follow the agro-pastoral mode of living. The majority of the households specialized on on-farm activities or livestock production for their income sources. A few households in the study areas engaged in off farm activities e.g., daily laborers and petty trades. The majority of households viewed that livestock were the main causes for the spread of P. juliflora in their areas. Few people in Amibara district were of the opinion that a foreigner working in the Middle Awash Irrigation project was the culprit for the introduction of P. juliflora into the Afar region.

In general, the household use of P. juliflora is minimal in the study area. The majority of households were not using P. juliflora at all. Some households used P. juliflora as shade for livestock. A few households used P.juliflora for traditional medicines to cure their livestock and human beings. The leaf of P. juliflora was the part mainly used than other parts of the plant.

The severe invasion of rangelands was indicative of the fact that livestock production and productivity were ultimately hampered in the study area, thus making agro-pastoral livelihood at risk. P. juliflora also blocked roads and pathways so much that accessibility of grazing areas became more difficult for livestock and human beings. The majority of households in both Districts were of the view that P. juliflora had no impacts on biodiversity particularly on plants. Moreover, the species has encroached into lower topographic areas: homesteads, and wetland areas. People had made attempts to control P. juliflora using fire, mechanical clear-cutting, and control through utilization (e.g., charcoal making, utilization of its woods for different purposes). Thus, it’s advisable in ussing P. juliflora to redue its further invasion into rangelands and other landuses in the region.

Variables definition and measurements [57].

(DOCX)

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Effects of site variation on perceptions of communities towards introduction, use, and effects of P. juliflora in Amibara and Awash Fentale Woredas.

(DOCX)

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(DOCX)

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7 Jun 2021

Submitted filename: Answer.docx

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22 Oct 2021

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8 Dec 2021

Answer

Journal: PLOS ONE

Manuscript ID: PONE-D-20-29179

Editor concerns: There are various serious concerns: i) the analysis conducted with the data: a serious pitfall in transforming categorical data before undertaking non-parametric analysis; the results, interpretation and conclusion are not therefore convincing; ii) lots of unnecessary details are given in the results and the discussion sections which clearly impede the focus of the message; iii) the manuscript needs a thorough editing to improve readability and grammatical oddities that are maintained throughout.

Answer: We tried to edit and reduce the errors; the manuscript is edited to correct grammatical errors and its readability. The manuscript is substantially revised and changed by the authors especially by corresponding author (Dr. Wakshum Shiferaw), Co-authors: Prof. Tamrat Bekele and Dr. Ermias Aynekulu. Prof. Sebsbe Demissew is another co-author who had given technical advisee for the improvement of the paper.

Reviewer #1

Concern: (1) You noted that the data were not normally distributed which is probably correct. Most of the input data are in fact categorical and should not be transformed. The data were then transformed before being analyzed using non-parametric methods. The transformation is inappropriate and may have affected your results. The data must be analyzed using methods designed for such data

Answer: The data now analyzed using methods designed for data analysis before transformation

Concern (2): You only mention the SPSS package but not the actual routines/tools/methods used to do the analysis. It is essential that you are as explicit as possible in describing what you did because I need to know that you used an appropriate tool/method. The results and the discussion sections are very lengthy and loaded with detail which would be of little interest to most of the prospective readers (and is generally evident in the figures). Try to reduce them to the essentials and try to focus on exploring the reasons why people may have given the responses they did and why there were differences between the districts that you sampled. The more succinct you can be the more likely it is that people will read and cite your paper.

Answer

Now we tried to mention the appropriate methods used for the analysis

The length section of results and discussions are reduced

Reviewer #2

Concerns

1. It has to be acknowledged that the method used in this study need some clarification;

Answer: now it is clear

2. The writing style in all sections of the paper need to be revised;

Revised

3. The introduction must be restructured to clearly show and demonstrate the relevance and importance of your study as well as its added value to the wealth of knowledge on the same subject;

Answer: Improved

4. The data analysis is largely descriptive;

Yes the nature of the title

5. The section “results” is so long and not straightforward;

Answer: reduced

Specific comments are well taken and the document is improved

Submitted filename: Response to reviewers.docx

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13 Dec 2021

Community perceptions towards invasion of Prosopis juliflora, utilization , and its control options in Afar region, Northeast Ethiopia

PONE-D-21-18433R1

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The paper has been thoroughly edited, with the authors taking into account the reviewers' suggestions as well as their remarks in order to improve the manuscript. I believe the work is scientifically appropriate for publication in the journal, and I recommend that it be accepted for publication.

Reviewers' comments:

17 Jan 2022

PONE-D-21-18433R1

Community perceptions towards invasion of Prosopis juliflora, utilization, and its control options in Afar region, Northeast Ethiopia

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