Authors: Mauricio Almeida-Gomes and Carlos F.D. Rocha
Journal: Biotropica:
The Journal of Tropical Biology and Conservation
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Habitat fragmentation and
modification are only a couple of the multiple impacts that human society has
had on the surrounding ecosystem that cause environmental risks to the resident
fauna, especially amphibians and reptiles. Habitat fragmentation significantly
affects the ones that have aquatic larvae, especially, due to the terrestrial
portion of the environment being physically separated by the aquatic one by a
road or bridge, along with other human-produced barriers. In Southern Brazil,
research has been done to analyze the effect of fragmentation and habitat loss
specifically on local anuran reproductive modes that are found in the area.
The research centered on sampling
various anuran species from continuous forested, fragments of different sizes,
and pasture areas in order to observe the wide range of reproductive modes that
are mainly used in the different site types. The sampling occurred through several visual encounter surveys (VES) over three years in each sampling area. The smaller fragments of land and
matrix areas had fewer reproductive modes found in comparison to the continuous
forested areas. Also, the larger fragmented areas tended to have a greater
number of reproductive sites in comparison to smaller ones, correlating with
the idea that larger fragments would likely have a wider variety of habitats,
which would allow more reproductive modes to be seen as it provides the means
for various species to reproduce. The fact that was an overall loss of
reproductive modes in comparison to the continuous forested areas shows how the
fragmentation of the land had affected the local anuran fauna. There are a
variety of species that have reproductive modes that require certain
environmental constraints, such as those that need both terrestrial for adults
and aquatic for larvae. Once the land fragmented, it is likely that the aquatic
area became separated from the terrestrial one by a border, or disappeared
completely, causing a loss of reproductive and species variety in a single area
as the species that require an aquatic area nearby were not able to reproduce
as effectively as before.
While the article only focuses on
anurans, it still shows how greatly habitat fragmentation or modification can
affect a single group of animals in an area. Amphibians and reptiles, along
with other orders, have evolved behavioral and survival attributes that require
certain landscapes to remain static, but the growth of the human population has
caused physical barriers that are negatively affecting the variety of local
species. It can be detrimental to an ecosystem if multiple species become
extinct in an area, even one as small as a local habitat. Luckily, there are
many societies around the world that have tried to accommodate the needs of
animals by providing tunnels or overpasses that connect the separated areas
again, or create warning signs for the local human population so that they are
aware that animals will cross a barrier (road, pathway, etc) in order to reach
the other side for their survival and reproductive purposes. Fragmentation and modification of a habitat do
not just affect fauna on a large scale, but also a smaller one as it decreases
the species variety through reproductive hindrance which in turn affects
survival of the population.
Almeida-Gomes,
M., Rocha, C. F. D. 2015. Habitat Loss Reduces Diversity of Frog Reproductive
Modes in an Atlantic Forest Fragmented Landscape. Biotropica. 47(1): 113-118.
Additional links to supporting or separate information can
be found as well.
1 comment:
This article is fascinating. It's interesting (and unfortunate) that entire reproductive modes are lost in the altered habitats, especially more derived modes like terrestrial breeding. A loss of life history diversity as well as species diversity.
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