Environmental and anthropogenic drivers of coniferous species distribution in Mediterranean drylands from North West Algeria

Abstract

Understanding the influence of environmental and anthropogenic factors on the distribution of species is essential for developing management in endangered ecosystems. We studied the current abundance and distribution patterns of vegetation along environmental and anthropogenic gradients by shaping their distribution in North West Algeria. We put special emphasis in the four dominant coniferous species (Pinus halepensis, Tetraclinis articulata, Juniperus oxycedrus and Juniperus phoenicea). We compiled inventories of species composition, together with 12 environmental variables in 177 sampling plots throughout the study area. Multivariate and univariate analyses were applied to predict presence of coniferous species and to explore speciesenvironment relationships along ecological and anthropogenic variables. We found that species segregated along environmental gradients, mainly altitude and related climatic variables (temperatures). Anthropogenic variables, like fire frequency and overgrazing, were secondary, but also significant. J. phoenicea was located exclusively in coastal areas. T. articulata had a wide distribution and was linked to coastal and inland areas, but did not arrive at more continental areas (colder and drier), where it was replaced with J. oxycedrus. P. halepensis displayed the widest distribution and was practically present throughout the study area, but its maximum distribution was in continental areas. These results indicate a possible shift of species' potential distribution in future climatic change. Species like J. oxycedrus would be seriously threatened by niche narrowing, while P. halepensis and T. articulata could expand to a certain extent. Our results provide important inputs for optimising the management plans of coniferous species by considering environmental factors key modulators of vegetation distribution.

Past, present, and future geographic range of the relict Mediterranean and Macaronesian Juniperus phoenicea complex

“…Juniperus turbinata most frequently occurs between sea level and about 400 m, indicating its association with thermo‐Mediterranean climatic conditions and subarid to humid climate ombrotypes (Mazur et al., 2016; Rivas‐Martínez et al., 2004, 2017). The Mediterranean zone where J. turbinata grows has average temperatures ranging from 5 to 15°C during winter and 25 to 30°C during summer (Ayache et al., 2020; Calò et al., 2012; Lionello, 2012; Sánchez‐Salguero & Camarero, 2020; Ünal et al., 2003). The absolute minimum winter temperatures rarely fall below 0°C, and the maximum summer temperatures frequently reach 38–40°C (Walter & Lieth, 1964).…”

“…The absolute minimum winter temperatures rarely fall below 0°C, and the maximum summer temperatures frequently reach 38–40°C (Walter & Lieth, 1964). The annual average precipitation in this belt varies between 400 and 800 mm (Ayache et al., 2020; Elmahdy & Mohamed, 2016; Lionello et al., 2012; Walter & Lieth, 1964), the latter values being recorded in the Mediterranean and Atlantic coastal regions exposed to the west or north, with the direct influence of winds carrying humidity (Lionello et al., 2012). The current potential niche of the species receives an annual average precipitation of more than 600 mm, ranging from 100 to more than 1,250 mm (Table ).…”

“…Juniperus turbinata occurs in the Mediterranean region, mainly on the coast and at low elevations up to about 400 m; in the southernmost localities it can be found in the mountains, up to 2,400 m in the High Atlas, and 1,800-2,000 m in southwest Asia (Boratyński et al, 1992;Browicz & Zieliński, 1982;Charco, 2001;El Bana et al, 2010;Kerfoot & Lavranos, 1984;Lebreton & Rivera, 1989;Quézel & Barbero, 1981;Quézel et al, 1994). At coastal sites, J. turbinata colonizes maritime dunes and/or rocks, growing on either siliceous or calcium substrata (Ayache et al, 2020;Eliçin 1977;Loidi, 2017;Martinis et al, 2018). It forms populations that can be locally extensive.…”

Predicting suitable habitats of the major forest trees in the Saïda region (Algeria): A reliable reforestation tool

“…DEMs and their derived topographic indices (e.g., slope, aspect, and topographic wetness index) are routinely calculated using geographic information systems (GIS) and are widely used as surrogates for a variety of environmental variables measured in the field such as temperature, incoming solar radiation, and soil moisture (Hengl, Reuter, 2008), and have long been used for a wide range of studies in ecology (Leempoel et al, 2015;Lecours et al, 2016;Zhang et al, 2016). This is becoming a common practice in SDM ecological modeling (Lassueur et al, 2006;Mod et al, 2016;Zhanget al, 2016), as it is strongly correlated with temperature, precipitation, moisture, soil nutrients, and geomorphological processes (Agnew, Palutikof, 2000;Das et al, 2015;Leempoel et al, 2015;Ayache et al, 2020).…”

Checklist of the native tree flora of Algeria: diversity, distribution, and conservation

“…Khelifi (2002) and Harfouche et al (2005) briefly listed the native tree species present in the Algerian territory, counting 70-71 main and secondary species. There are also partial studies like the recent analysis of the influence of environmental vs anthropic factors for explaining the distribution of the four major coniferous species in North West Algeria (Ayache et al 2020). For the Sahara region, Sahki & Sahki (2004), Benchelah et al (2006), Kaabeche et al (2011), andSahki et al (2017) mention the existence of 35 to 40 native tree species growing in the whole Algerian Sahara (Great South).…”