22.1 Introduction
IUCN defines invasive species as “alien species which become established in
natural or semi-natural ecosystems or habitats, are an agent of change and threaten
native biological diversity” (McNeely et al. 2001). The invasive alien plants are
those which produce descendants, sometimes in large amounts, at considerable
distance from the parental plants and cover large stretches (Richardson et al. 2000).
A general pattern is that the spread of invasive plant species leads to the replacement of native species, because most invasive plants grow vigorously and form
extensive patches that tolerate only very few native species (Weber 2005).
The introduction of invasive species has increased with the modern trade and
travel, so that biological invasions have become a consequence of globalization that
facilitates the spread of invasive non-native species. The spread of invasive alien
species poses a serious threat to the conservation of natural and semi-natural
habitats (Weber 2005). They change the character, form or nature of ecosystems
and have a tremendous impact on the native floral communities. In the competition
between invasive plants and native plants, the invaders have a superior competitive
ability (Weber 2005).
Early detection and rapid assessment of invasive plants can limit the damage and
this allows an efficient control of the most dangerous species. Therefore, monitoring
programs are required in high risk areas or along transfer routes (Lodge et al. 2006).
The coastline has a higher proportion of alien plants compared with the inland
areas (Anastasiu et al. 2011). More than 80% of all alien species reported for
Dobrogea (140 taxa, according with Anastasiu and Negrean 2009) have been
noticed along the coastline, especially around the Constanta and Midia harbors.
Commercial navigation is one of the biggest sources of invasive plants. The
intense economic activities in the area of some maritime harbors (Constanta, Midia
and Mangalia) have increased the risk of accidental introduction into Romania of
some non-native invasive plants, especially south of Cape Midia, on the southern
Romanian Black Sea coast. Alien species subsequently spread along the seacoast,
through the transportation of goods and due to the mobility of humans and their
pets. Tourists, on their clothes and shoes, as well as pets on their fur, have
introduced seeds, fruits or fragments of alien species in the coastal area.
In the natural habitats of the littoral zone, invasive plants can cause the local
extinction of some native species (Fa ˘ga ˘raș and Niculescu 2015), for instance
through competition for limited resources (food, light, space). The impact of
some invasive species may sometimes be so profound that they can alter the
structure and functioning of the coastal ecosystems (Weber 2005).
Field surveys carried out in the coastal area of Romania in the past years, have
led to the identification of some alien plants which have a typical behavior for
invasive species. Such a species is Cenchrus longispinus (longspine sandbur), an
aggressive alien plant which has already become abundant on different beaches of
Mamaia resort and is an element of discomfort for the tourists who walk barefoot on
the beach.
384
M. Fa ˘ga ˘raș
IUCN defines invasive species as “alien species which become established in
natural or semi-natural ecosystems or habitats, are an agent of change and threaten
native biological diversity” (McNeely et al. 2001). The invasive alien plants are
those which produce descendants, sometimes in large amounts, at considerable
distance from the parental plants and cover large stretches (Richardson et al. 2000).
A general pattern is that the spread of invasive plant species leads to the replacement of native species, because most invasive plants grow vigorously and form
extensive patches that tolerate only very few native species (Weber 2005).
The introduction of invasive species has increased with the modern trade and
travel, so that biological invasions have become a consequence of globalization that
facilitates the spread of invasive non-native species. The spread of invasive alien
species poses a serious threat to the conservation of natural and semi-natural
habitats (Weber 2005). They change the character, form or nature of ecosystems
and have a tremendous impact on the native floral communities. In the competition
between invasive plants and native plants, the invaders have a superior competitive
ability (Weber 2005).
Early detection and rapid assessment of invasive plants can limit the damage and
this allows an efficient control of the most dangerous species. Therefore, monitoring
programs are required in high risk areas or along transfer routes (Lodge et al. 2006).
The coastline has a higher proportion of alien plants compared with the inland
areas (Anastasiu et al. 2011). More than 80% of all alien species reported for
Dobrogea (140 taxa, according with Anastasiu and Negrean 2009) have been
noticed along the coastline, especially around the Constanta and Midia harbors.
Commercial navigation is one of the biggest sources of invasive plants. The
intense economic activities in the area of some maritime harbors (Constanta, Midia
and Mangalia) have increased the risk of accidental introduction into Romania of
some non-native invasive plants, especially south of Cape Midia, on the southern
Romanian Black Sea coast. Alien species subsequently spread along the seacoast,
through the transportation of goods and due to the mobility of humans and their
pets. Tourists, on their clothes and shoes, as well as pets on their fur, have
introduced seeds, fruits or fragments of alien species in the coastal area.
In the natural habitats of the littoral zone, invasive plants can cause the local
extinction of some native species (Fa ˘ga ˘raș and Niculescu 2015), for instance
through competition for limited resources (food, light, space). The impact of
some invasive species may sometimes be so profound that they can alter the
structure and functioning of the coastal ecosystems (Weber 2005).
Field surveys carried out in the coastal area of Romania in the past years, have
led to the identification of some alien plants which have a typical behavior for
invasive species. Such a species is Cenchrus longispinus (longspine sandbur), an
aggressive alien plant which has already become abundant on different beaches of
Mamaia resort and is an element of discomfort for the tourists who walk barefoot on
the beach.
384
M. Fa ˘ga ˘raș