Learn Swedish: Vi måste skydda den av klimatförändringen svårt drabbade arten. - We must protect the species severely affected by climate change.

This is a complex pre-modifying participial attribute, which is common in formal written Swedish. Instead of putting a descriptive clause after the noun (like 'the species that is severely affected by...'), Swedish often packs the entire phrase between the independent definite article (den) and the noun (arten). Think of it as treating the whole phrase as one giant adjective.

Why does the past participle drabbade end in an '-e' here instead of being drabbad?

Because it is acting as an adjective inside a definite noun phrase. When a noun phrase starts with a freestanding definite article like den, the adjectives or participles following it must take their definite form. The definite form of the past participle drabbad is drabbade.

A quick refresher: why do we use both den and the definite ending on arten?

This is the Swedish double definite rule. When a definite noun is modified by an adjective or a participial phrase, you must use both the independent article before the adjective (den for en-words) and the definite suffix on the noun itself (-en in arten). It literally builds 'the [modifier] species-the'.

In English we say 'by climate change', but the Swedish uses the definite form klimatförändringen. Why?